Design Manual

M 22-01.18
December 2019

Division 1 – General Information

Division 2 – Hearings, Environmental, and Permits
Division 3 – Project Documentation
Division 4 – Surveying
Division 5 – Right of Way and Access Control
Division 6 – Soils and Paving
Division 7 – Structures
Division 8 – Hydraulics
Division 9 – Roadside Development
Division 10 – Traffic Safety Elements
Division 11 – Practical Design
Division 12 – Geometrics
Division 13 – Intersections and Interchanges
Division 14 – HOV and Transit
Division 15 – Pedestrian and Bicycle Facilities
Division 16 – Roadside Safety Elements
Division 17 – Roadside Facilities

Engineering and Regional Operations

Development Division, Design Office
Americans with Disabilities Act (ADA) Information
Materials can be made available in an alternative format by emailing the WSDOT Diversity/ADA
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who are deaf or hard of hearing may contact that number via the Washington Relay Service at
7-1-1.

Title VI Notice to Public

It is Washington State Department of Transportation (WSDOT) policy to ensure no person
shall, on the grounds of race, color, national origin, or sex, as provided by Title VI of the Civil
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 Foreword
The Design Manual is for use by Washington State Department of Transportation personnel,
consultants and contractors engaged in transportation design. It provides policies, procedures,
and methods for developing and documenting the design of improvements to the
transportation network in Washington. It has been developed for state facilities and may not
be appropriate for all county roads or city streets that are not state highways.

The Federal Highway Administration has agreed to approve designs that follow the guidance in
the Design Manual; therefore, following the guidance is mandatory for state highway projects.
When proposed designs meet the requirements contained in the Design Manual, little
additional documentation is required.

The Design Manual supplements the engineering analyses and judgment inherent with
practical design and provides uniform procedures for documenting and implementing design
decisions. The Design Manual emphasizes practical design as a means to produce
environmentally conscious, sustainable, context-based designs that achieve the purpose and
need for the lowest cost. Practical design considers the needs of all users, fostering livable
communities and modally integrated transportation systems used safely by all, including
motorists, freight haulers, transit, pedestrians, and bicyclists.

The complexity of transportation design requires designers to make fundamental trade-off

decisions and sometimes incremental approaches to balance competing spatial considerations
with available resources. Although this adds to the complexity of design, it acknowledges the
unique needs of specific projects and the relative priorities of various projects and programs.

Updating the Design Manual is an ongoing process and revisions are issued regularly. The
addition of new or modified design criteria to the Design Manual through the revision process
does not imply that existing features are deficient in any way, nor does it suggest or mandate
immediate engineering review or initiation of new projects. Comments, questions, and
improvement ideas are welcomed. Use the comment form on the next page or the contact
information on the Design Policy Internet Page:  www.wsdot.wa.gov/design/policy

/s/ Steve Roark

Steve Roark, P.E.
Director & State Design Engineer,
Development Division

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Foreword

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 Comment Form

From: ___________________________________________ Date: ___________________

___________________________________________ Phone: ___________________

___________________________________________

To: WSDOT Headquarters

Development Division, Design Office

Attn: Policy, Standards, and Research Section

PO Box 47329

Olympia, WA 98504-7329

Subject: Design Manual Comment

Comment:

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Comment Form

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 Contents
Division 1 – General Information
Chapter 100 Manual Description
100.01 Purpose
100.02 Presentation and Revisions
100.03 Practical Solutions
100.04 Manual Applications
100.05 Manual Use
100.06 Manual Organization
Chapter 110 Design-Build Projects
110.01 General
110.02 Terminology and Language Used
110.03 Design and Documentation Responsibility
110.04 References

Division 2 – Hearings, Environmental, and Permits

Chapter 210 Public Involvement and Hearings
210.01 General
210.02 References
210.03 Definitions
210.04 Public Involvement
210.05 Public Hearings
210.06 Environmental Hearing
210.07 Corridor Hearing
210.08 Design Hearing
210.09 Limited Access Hearing
210.10 Combined Hearings
210.11 Administrative Appeal Hearing
210.12 Follow-Up Hearing
210.13 Documentation
Chapter 225 Environmental Coordination
225.01 General
225.02 References
225.03 Determining the Environmental Documentation
225.04 Identifying the Project Classification
225.05 Environmental Commitment File
225.06 Environmental Permits and Approvals
225.07 Documentation

Division 3 – Project Documentation

Chapter 300 Design Documentation, Approval, and Process Review
300.01 General
300.02 WSDOT Project Delivery
300.03 Design Documentation and Records Retention Policy
300.04 Project Design Approvals
300.05 FHWA Oversight and Approvals
300.06 Project Documents and Approvals
300.07 Process Review
300.08 References

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Chapter 301 Design and Maintenance Coordination

301.01 Introduction
301.02 Communication
301.03 Incorporating Maintenance Considerations in Design
301.04 Documentation
301.05 References
Chapter 305 Project Management
305.01 Introduction
305.02 Project Management
305.03 Project Management Tools
305.04 Cost and Risk Management
305.05 References
Chapter 310 Value Engineering
310.01 General
310.02 Statewide VE Program
310.03 VE Procedure
310.04 Value Engineering Job Plan
310.05 Project Management Accountability
310.06 Documentation
310.07 References
Chapter 320 Traffic Analysis
320.01 General
320.02 Design Year and Forecasting Considerations
320.03 Traffic Analysis Software
320.04 Travel Demand Forecasting
320.05 Traffic Impact Analysis (TIA)
320.06 TIA Scope
320.07 TIA Methods and Assumptions Document
320.08 TIA Methodologies
320.09 TIA Mitigation Measures
320.10 TIA Report
320.11 References
Chapter 321 Sustainable Safety Analysis
321.01 Sustainable Safety Related Policy
321.02 HQ Safety Technical Group
321.03 Project Related Safety Analysis
321.04 Stand Alone Safety Analysis
321.05 Reports and Documentation
321.06 References

Division 4 – Surveying
Chapter 400 Surveying and Mapping
400.01 General
400.02 References
400.03 Procedures
400.04 Datums
400.05 Global Positioning System
400.06 WSDOT Survey Monument Database
400.07 Geographic Information System
400.08 Photogrammetric Surveys
400.09 Documentation

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Chapter 410 Monumentation

410.01 General
410.02 References
410.03 Control Monuments
410.04 Alignment Monuments
410.05 Property Corners
410.06 Other Monuments
410.07 Filing Requirements
410.08 Documentation

Division 5 – Right of Way and Access Control

Chapter 510 Right of Way Considerations
510.01 General
510.02 Special Features
510.03 Easements and Permits
510.04 Programming for Funds
510.05 Appraisal and Acquisition
510.06 Transactions
510.07 Documentation
510.08 References
Chapter 520 Access Control
520.01 General
520.02 References
520.03 Definitions
520.04 Vocabulary
Chapter 530 Limited Access Control
530.01 General
530.02 Achieving Limited Access
530.03 Full Control (Most Restrictive)
530.04 Partial Control
530.05 Modified Control (Least Restrictive)
530.06 Access Approaches
530.07 Frontage Roads
530.08 Turnbacks
530.09 Adjacent Railroads
530.10 Access Breaks and Inner Corridor Access
530.11 Documentation
Chapter 540 Managed Access Control
540.01 General
540.02 Design Considerations
540.03 Managed Access Highway Classes
540.04 Corner Clearance Criteria
540.05 Access Connection Categories
540.06 Access Connection Permit
540.07 Permitting and Design Documentation
540.08 Other Considerations
540.09 Preconstruction Conference
540.10 Adjudicative Proceedings
540.11 Documentation
540.12 References

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Chapter 550 Freeway Access Revision

550.01 Overview
550.02 Freeway Access Policy
550.03 Access Revision Analysis Process
550.04 Support Teams
550.05 Non-Access Feasibility Study
550.06 Access Revision Report Process
550.07 Documentation
550.08 References
Chapter 560 Fencing
560.01 General
560.02 Design Criteria
560.03 Fencing Types
560.04 Gates
560.05 Procedure
560.06 Documentation
560.07 References

Division 6 – Soils and Paving

Chapter 610 Investigation of Soils, Rock, and Surfacing Materials
610.01 General
610.02 References
610.03 Materials Sources
610.04 Geotechnical Investigation, Design, and Reporting
610.05 Use of Geotechnical Consultants
610.06 Geotechnical Work by Others
610.07 Surfacing Report
610.08 Documentation
Chapter 620 Design of Pavement Structure
620.01 General
620.02 Estimating Tables
Chapter 630 Geosynthetics
630.01 General
630.02 References
630.03 Geosynthetic Types and Characteristics
630.04 Geosynthetic Function Definitions and Applications
630.05 Design Approach for Geosynthetics
630.06 Design Responsibility
630.07 Documentation

Division 7 – Structures
Chapter 700 Project Development Roles and Responsibilities for Projects
With Structures
700.01 General
700.02 Procedures
Chapter 710 Site Data for Structures
710.01 General
710.02 Required Data for All Structures
710.03 Additional Data for Waterway Crossings (Bridges and
Buried Structures)
710.04 Additional Data for Grade Separations

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710.05 Additional Data for Widenings

710.06 Documentation
710.07 References
Chapter 720 Bridges
720.01 General
720.02 Bridge Locations
720.03 Bridge Site Design Elements
720.04 Documentation
720.05 References
Chapter 730 Retaining Walls and Steep Reinforced Slopes
730.01 General
730.02 References
730.03 Design Principles
730.04 Design Requirements
730.05 Guidelines for Wall/Slope Selection
730.06 Design Responsibility and Process
730.07 Documentation
Chapter 740 Noise Barriers
740.01 General
740.02 Design
740.03 Procedures
740.04 Documentation
740.05 References

Division 8 – Hydraulics
Chapter 800 Hydraulic Design
800.01 General
800.02 References
800.03 Hydraulic Considerations
800.04 Safety Considerations
800.05 Design Responsibility
800.06 Documentation

Division 9 – Roadside Development

Chapter 900 Roadsides
900.01 General
900.02 References
900.03 Project Development
900.04 Documentation
Chapter 950 Public Art
950.01 General
950.02 References
950.03 Standard Architectural Design
950.04 Criteria for Public Art
950.05 Process and Project Delivery Timing
950.06 Approvals
950.07 Documentation

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Division 10 – Traffic Safety Elements

Chapter 1010 Work Zone Safety and Mobility
1010.01 General
1010.02 Definitions
1010.03 Work Zone Safety and Mobility
1010.04 Transportation Management Plans and Significant Projects
1010.05 Developing TMP Strategies
1010.06 Work Zone Capacity Analysis
1010.07 Work Zone Design
1010.08 Temporary Traffic Control Devices
1010.09 Positive Protection Devices
1010.10 Other Traffic Control Devices or Features
1010.11 Traffic Control Plan Development and PS&E
1010.12 Training and Resources
1010.13 Documentation
1010.04 References
Chapter 1020 Signing
1020.01 General
1020.02 Design Components
1020.03 Overhead Installation
1020.04 State Highway Route Numbers
1020.05 Mileposts
1020.06 Guide Sign Plan
1020.07 Documentation
1020.08 References
Chapter 1030 Delineation
1030.01 General
1030.02 Definitions
1030.03 Pavement Markings
1030.04 Guideposts
1030.05 Barrier Delineation
1030.06 Object Markers
1030.07 Documentation
1030.08 References
Chapter 1040 Illumination
1040.01 General
1040.02 Definitions
1040.03 Design Considerations
1040.04 Required Illumination
1040.05 Additional Illumination
1040.06 Design Criteria
1040.07 Documentation
1040.08 References
Chapter 1050 Intelligent Transportation Systems
1050.01 General
1050.02 References
1050.03 Systems Engineering
1050.04 FHWA Washington Division ITS Project Contracting Guidance
1050.05 Documentation

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Division 11 – Practical Design

Chapter 1100 Practical Design
1100.01 General
1100.02 Practical Design Procedure
1100.03 Community Engagement
1100.04 Advisory Team
1100.05 Need and Performance Identification
1100.06 Context Identification
1100.07 Design Control Selection
1100.08 Alternative Formulation and Evaluation
1100.09 Design Element Selection and Dimensions
1100.10 Documentation Tools
1100.11 References
Chapter 1101 Need Identification
1101.01 General
1101.02 Baseline Needs
1101.03 Contextual Needs
1101.04 Contributing Factors Analysis
1101.05 Project Need Statement
1101.06 Documentation
1101.07 References
Chapter 1102 Context Determination
1102.01 General Overview
1102.02 Land Use Context
1102.03 Transportation Context
1102.04 Documentation
1102.05 References
Chapter 1103 Design Control Selection
1103.01 General Overview
1103.02 Control: Design Year
1103.03 Control: Modal Priority
1103.04 Control: Access Control
1103.05 Control: Design Speed
1103.06 Control: Terrain Classification
1103.07 Documentation
1103.08 References
Chapter 1104 Alternatives Analysis
1104.01 General
1104.02 Alternative Solution Formulation
1104.03 Alternative Solution Evaluation
1104.04 Documentation
1104.05 References
Chapter 1105 Design Element Selection
1105.01 General
1105.02 Selecting Design Elements
1105.03 Related Elements
1105.04 Documentation
1105.05 References

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Chapter 1106 Design Element Dimensions

1106.01 General
1106.02 Choosing Dimensions
1106.03 The Mode/Function/Performance Approach
1106.04 Design Up Method
1106.05 Quantitative Analysis Methods and Tools
1106.06 Documenting Dimensions
1106.07 Design Analysis
1106.08 References
Chapter 1120 Preservation Projects
1120.01 General
1120.02 Structures Preservation (P2) and Other Facilities (P3)
1120.03 Roadway Preservation (P1)
1120.04 Documentation

Division 12 – Geometrics
Chapter 1210 Geometric Plan Elements
1210.01 General
1210.02 Horizontal Alignment
1210.03 Distribution Facilities
1210.04 Number of Lanes and Arrangement
1210.05 Pavement Transitions
1210.06 Procedures
1210.07 Documentation
1210.08 References
Chapter 1220 Geometric Profile Elements
1220.01 General
1220.02 Vertical Alignment
1220.03 Coordination of Vertical and Horizontal Alignments
1220.04 Airport Clearance
1220.05 Railroad Crossings
1220.06 Procedures
1220.07 Documentation
1220.08 References
Chapter 1230 Geometric Cross Section Basics
1230.01 General
1230.02 Guidance for Specific Facility Types
1230.03 Common Elements
1230.04 Jurisdiction for Design and Maintenance
1230.05 References
Chapter 1231 Geometric Cross Section – Highways
1231.01 General
1231.02 Design Up
1231.03 Common Elements
1231.04 Vehicle Lanes
1231.05 Modally Integrated Cross Sections
1231.06 Road Diets and Retrofit Options
1231.07 References
Chapter 1232 Geometric Cross Section – Freeways
1232.01 General

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1232.02 Lane Width

1232.03 Shoulder Width
1232.04 Other Elements
1232.05 Design Flexibility
1232.06 References
Chapter 1238 Geometric Cross Section – Streetside and Parking
1238.01 General
1238.02 Parking
1238.03 Streetside
1238.04 Retrofit Options
1238.05 References
Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs,
and Medians
1239.01 Introduction
1239.02 Shoulders
1239.03 Side Slopes and Ditches
1239.04 Roadway Sections in Rock Cuts
1239.05 Curbs
1239.06 Lateral Clearance to Curb and Barrier
1239.07 Medians & Outer Separations
Chapter 1240 Turning Roadways
1240.01 General
1240.02 Turning Roadway Widths
1240.03 Documentation
1240.04 References
Chapter 1250 Cross slope and Superelevation
1250.01 General
1250.02 Roadway Cross Slope
1250.03 Superelevation Rate Selection
1250.04 Existing Curves
1250.05 Turning Movements at Intersections
1250.06 Runoff for Highway Curves
1250.07 Runoff for Ramp Curves
1250.08 Documentation
1250.09 References
Chapter 1260 Sight Distance
1260.01 General
1260.02 References
1260.03 Stopping Sight Distance
1260.04 Passing Sight Distance
1260.05 Decision Sight Distance
1260.06 Documentation
Chapter 1270 Auxiliary Lanes
1270.01 General
1270.02 Climbing Lanes
1270.03 Passing Lanes
1270.04 Slow-Moving Vehicle Turnouts
1270.05 Shoulder Driving for Slow Vehicles
1270.06 Emergency Escape Ramps
1270.07 Chain-Up and Chain-Off Areas
1270.08 Documentation

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1270.09 References

Division 13 – Intersections and Interchanges

Chapter 1300 Intersection Control Type
1300.01 General
1300.02 Intersection Control Objectives
1300.03 Common Types of Intersection Control
1300.04 Modal Considerations
1300.05 Procedures
1300.06 Documentation
1300.07 References
Chapter 1310 Intersections
1310.01 General
1310.02 Design Considerations
1310.03 Design Elements
1310.04 U-Turns
1310.05 Intersection Sight Distance
1310.06 Signing and Delineation
1310.07 Procedures
1310.08 Documentation
1310.09 References
Chapter 1320 Roundabouts
1320.01 General
1320.02 Roundabout Types
1320.03 Capacity Analysis
1320.04 Geometric Design
1320.05 Pedestrians
1320.06 Bicycles
1320.07 Signing
1320.08 Pavement Marking
1320.09 Illumination
1320.10 Road Approach, Parking, and Transit Facilities
1320.11 Geometric Design Peer Review
1320.12 Documentation and Approvals
1320.13 References
Chapter 1330 Traffic Control Signals
1330.01 General
1330.02 Procedures
1330.03 Intersection Design Considerations
1330.04 Conventional Traffic Signal Design
1330.05 Preliminary Signal Plan
1330.06 Operational Considerations for Design
1330.07 Documentation
1330.08 References
Chapter 1340 Driveways
1340.01 General
1340.02 References
1340.03 Design Considerations
1340.04 Driveway Design Templates
1340.05 Sidewalks
1340.06 Driveway Sight Distance
1340.07 Stormwater and Drainage

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1340.08 Mailboxes
1340.09 Documentation
Chapter 1350 Railroad Grade Crossings
1350.01 General
1350.02 References
1350.03 Plans
1350.04 Traffic Control Systems
1350.05 Nearby Roadway Intersections
1350.06 Pullout Lanes
1350.07 Crossing Surfaces
1350.08 Crossing Closure
1350.09 Traffic Control During Construction and Maintenance
1350.10 Railroad Grade Crossing Petitions and WUTC Orders
1350.11 Grade Crossing Improvement Projects
1350.12 Light Rail
1350.13 Documentation
Chapter 1360 Interchanges
1360.01 General
1360.02 Interchange Design
1360.03 Ramps
1360.04 Interchange Connections
1360.05 Ramp Terminal Intersections at Crossroads
1360.06 Interchanges on Two-Lane Highways
1360.07 Interchange Plans for Approval
1360.08 Documentation
1360.09 References
Chapter 1370 Median Crossovers
1370.01 General
1370.02 Analysis
1370.03 Design
1370.04 Plan Updates and Approvals
1370.05 Documentation

Division 14 – HOV and Transit

Chapter 1410 High-Occupancy Vehicle Facilities
1410.01 General
1410.02 Preliminary Design and Planning
1410.03 Operations
1410.04 Design Criteria
1410.05 Documentation
1410.06 References
Chapter 1420 HOV Direct Access
1420.01 General
1420.02 HOV Access Types and Locations
1420.03 Direct Access Geometrics
1420.04 Passenger Access
1420.05 Traffic Design Elements
1420.06 Documentation
1420.07 References
Chapter 1430 Transit Facilities
1430.01 General

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1430.02 Bus Stops and Pullouts

1430.03 Passenger Amenities
1430.04 Park and Ride Lots
1430.05 Transfer/Transit Centers
1430.06 Roadway and Intersection Design
1430.07 Documentation
1430.08 References

Division 15 – Pedestrian and Bicycle Facilities

Chapter 1510 Pedestrian Facilities
1510.01 General
1510.02 References
1510.03 Definitions
1510.04 Policy
1510.05 ADA Requirements by Project Type
1510.06 Pedestrian Circulation Paths
1510.07 Pedestrian Access Routes (PARs)
1510.08 Sidewalks
1510.09 Curb Ramps
1510.10 Crosswalks
1510.11 Raised Medians/Traffic Islands
1510.12 Pedestrian Pushbuttons
1510.13 At-Grade Railroad Crossings
1510.14 Pedestrian Grade Separations (Structures)
1510.15 Other Pedestrian Facilities
1510.16 Illumination and Signing
1510.17 Work Zone Pedestrian Accommodation
1510.18 Documentation
Chapter 1515 Shared-Use Paths
1515.01 General
1515.02 References
1515.03 Definitions
1515.04 Shared-Use Path Design – The Basics
1515.05 Intersections and Crossings Design
1515.06 Grade Separation Structures
1515.07 Signing, Pavement Markings, and Illumination
1515.08 Restricted Use Controls
1515.09 Documentation
Chapter 1520 Roadway Bicycle Facilities
1520.01 General
1520.02 Roadway Bicycle Facility Types
1520.03 Bicycle Facility Selection
1520.04 Intersection Design Treatments
1520.05 Additional Bicycle Design Requirements and Considerations
1520.06 Documentation
1520.07 References

Division 16 – Roadside Safety Elements

Chapter 1600 Roadside Safety
1600.01 General
1600.02 Clear Zone
1600.03 Mitigation Guidance

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1600.04 Medians
1600.05 Other Roadside Safety Features
1600.06 Documentation
1600.07 References
Chapter 1610 Traffic Barriers
1610.01 Introduction
1610.02 Barrier Impacts
1610.03 General Barrier Design Considerations
1610.04 Beam Guardrail
1610.05 High-Tension Cable Barrier
1610.06 Concrete Barrier
1610.07 Bridge Traffic Barriers
1610.08 Other Barriers
1610.09 References
Chapter 1620 Impact Attenuator Systems
1620.01 General
1620.02 Design Criteria
1620.03 Selection Considerations
1620.04 Transportable Attenuators (Truck-Mounted and Trailer-Mounted)
1620.05 Older Systems
1620.06 Inertial Barrier Systems (Sand Barrels)

Division 17 – Roadside Facilities

Chapter 1710 Safety Rest Areas and Traveler Services
1710.01 General
1710.02 References
1710.03 Definitions
1710.04 Safety Rest Area Project Team
1710.05 Location, Access, and Site Design
1710.06 Buildings
1710.07 Utilities
1710.08 Documentation
Chapter 1720 Weigh Sites
1720.01 General
1720.02 Definitions
1720.03 Planning, Development, and Responsibilities
1720.04 Permanent Facilities
1720.05 Portable Facilities
1720.06 Shoulder Sites
1720.07 Federal Participation
1720.08 Procedures
1720.09 Documentation

Glossary

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 Exhibits

110-1 Design Documentation Sequence for a Typical Design-Build Project

210-1 Types of Public Hearings
210-2 Public Hearing Formats
210-3 Prehearing Packet Checklist
210-4 Sequence for Corridor, Design, and Environmental Hearings
210-5 Sequence for Limited Access Hearing
210-6 Hearing Summary Approvals
300-1 Approval Authorities
300-2 Approvals
300-3 PS&E Process Approvals NHS (Including Interstate) and Non-NHS
300-4 Design to Construction Transition Project Turnover Checklist Example
300-5 Local Agency and Developer Approvals
301-1 General Input Form with Listed Performance Objectives
301-2 Design Option Worksheet Showing Example of Life Cycle Cost Assessment
301-3 Excerpts from Olympic Region Review Checklist
305-1 WSDOT Project Management Process
310-1 Seven-Phase Job Plan for VE Studies
310-2 VE Analysis Team Tools
310-3 Value Engineering Job Plan
400-1 Interagency Agreement
400-2 Report of Survey Mark Example
410-1 Monument Documentation Summary
410-2 DNR Permit Application
410-3 DNR Completion Report Form
410-4 Land Corner Record
510-1 Appraisal and Acquisition
520-1 Access Control Vocabulary
530-1a Full Access Control Limits: Interchange
530-1b Full Access Control Limits: Interchange
530-1c Full Access Control Limits: Interchange With Roundabouts
530-1d Full Access Control Limits: Ramp Terminal With Transition Taper
530-1e Full Access Control Limits: Single Point Urban Interchange
530-1f Full Access Control Limits: Diverging Diamond Interchange
530-2a Partial Access Control Limits: At-Grade Intersections
530-2b Partial Access Control Limits: Roundabout Intersections
530-3a Modified Access Control Limits: Roundabout Intersections

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 Exhibits

530-3b Modified Access Control Limits: Intersections

540-1 Managed Access Highway Class Description
540-2 Minimum Corner Clearance: Distance From Access Connection to Public Road or Street
550-1 Non-Access Feasibility Study Process
550-2 Access Revision Report Process
550-3 Access Revision Report: Stamped Cover Sheet Example
550-4 Access Revision Documentation and Review/Approval Levels
610-1 Materials Source Development
620-1 Estimating: Miscellaneous Tables
620-2 Estimating: Hot Mix Asphalt Pavement and Asphalt Distribution Tables
620-3 Estimating: Bituminous Surface Treatment
620-4 Estimating: Base and Surfacing Typical Section Formulae and Example
620-5a Estimating: Base and Surfacing Quantities
620-5b Estimating: Base and Surfacing Quantities
620-5c Estimating: Base and Surfacing Quantities
620-5d Estimating: Base and Surfacing Quantities
620-5e Estimating: Base and Surfacing Quantities
620-5f Estimating: Base and Surfacing Quantities
620-5g Estimating: Base and Surfacing Quantities
620-5h Estimating: Base and Surfacing Quantities
630-1 Selection Criteria for Geotextile Class
630-2 Maximum Sheet Flow Lengths for Silt Fences
630-3 Maximum Contributing Area for Ditch and Swale Applications
630-4 Design Process for Drainage and Erosion Control: Geotextiles and Nonstandard
Applications
630-5 Design Process for Separation, Soil Stabilization, and Silt Fence
630-6 Examples of Various Geosynthetics
630-7 Geotextile Application Examples
630-8 Definition of Slope Length
630-9 Definition of Ditch or Swale Storage Length and Width
630-10 Silt Fences for Large Contributing Area
630-11 Silt Fence End Treatment
630-12 Gravel Check Dams for Silt Fences
700-1 Determination of the Roles and Responsibilities for Projects With Structures: Project
Development Phase
710-1 Structure Site Data Checklist
710-2 Conceptual Plan Structure Site Data Checklist
720-1 Phased Development of Multilane Divided Highways
720-2 Highway Structure Over Railroad
720-3 Bridge Vertical Clearances

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Exhibits

720-4 Embankment Slope at Bridge Ends

730-1 Summary of Mechanically Stabilized Earth (MSE) Gravity Wall/Slope Options Available
730-2 Summary of Prefabricated Modular Gravity Wall Options Available
730-3 Summary of Rigid Gravity and Semigravity Wall Options Available
730-4 Summary of Nongravity Wall Options Available
730-5 Summary of Anchored Wall Options Available
730-6 Other Wall/Slope Options Available
730-7 Typical Mechanically Stabilized Earth Gravity Walls
730-8 Typical Prefabricated Modular Gravity Walls
730-9 Typical Rigid Gravity, Semigravity Cantilever, Nongravity Cantilever, and Anchored Walls
730-10 Typical Rockery and Reinforced Slopes
730-11 MSE Wall Drainage Detail
730-12 Retaining Walls With Traffic Barriers
730-13a Retaining Wall Design Process
730-13b Retaining Wall Design Process: Proprietary
740-1 Standard Noise Wall Types
1010-1 General Lane Closure Work Zone Capacity
1010-2 Minimum Work Zone Clear Zone Distance
1010-3 Transportation Management Plan Components Checklist
1020-1 Reflective Sheeting Requirements for Overhead Signs
1020-2 Timber Posts
1020-3 Wide Flange Steel Posts
1020-4 Laminated Wood Box Posts
1030-1 Pavement Marking Material Guide – Consult Region Striping Policy
1030-2 Guidepost Placement
1040-1a Freeway Lighting Applications
1040-1b Freeway Lighting Applications
1040-1c Freeway Lighting Applications
1040-2 Freeway Ramp Terminals
1040-3 Ramp With Meter
1040-4a HOT (High-Occupancy Toll) Lane Enter/Exit Zone
1040-4b HOT (High-Occupancy Toll) Lane Access Weave Lane
1040-5 Lane Reduction
1040-6a Intersection With Left-Turn Channelization: Divided Highway
1040-6b Intersections With Left-Turn Channelization
1040-6c Intersections With Raised Left-Turn Channelization
1040-7 Intersections With Traffic Signals
1040-8 Intersection Without Channelization
1040-9 Roundabout

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 Exhibits

1040-10 Railroad Crossing With Gates or Signals

1040-11 Midblock Pedestrian Crossing
1040-12 Transit Flyer Stop
1040-13 Major Parking Lot
1040-14 Minor Parking Lot
1040-15 Truck Weigh Site
1040-16 Safety Rest Area
1040-17 Chain-Up/Chain-Off Parking Area
1040-18 Bridge Inspection Lighting System
1040-19 Traffic Split Around an Obstruction
1040-20 Construction Work Zone and Detour
1040-21 Diverging Diamond Interchange
1040-22 Light Levels and Uniformity Ratios
1050-1 Systems Engineering Process (“V” Diagram)
1050-2 Intelligent Transportation Systems (ITS) Systems Engineering Analysis Worksheet
1050-3 FHWA Washington Division – ITS Project Contracting Guidance
1100-1 Basis of Design Flowchart
1102-1 Factors for Determining Initial Land Use Context
1103-1 WSDOT Design Controls
1103-2 Initial Modal Accommodation Level
1103-3 Example Characteristics Related to Modal Accomodation
1103-4 Target Speed Based on Land Use Context and Roadway Type
1103-5 Speed Transition Segment Example
1103-6 Geometric Traffic Calming Treatments and Considerations
1103-7 Roadside, Streetside, and Pavement-Oriented Traffic Calming Treatments
1105-1 Required Design Elements
1106-1 Dimensioning Guidance Variations
1106-2 Mode/Function/Performance Approach
1210-1 Maximum Angle Without Curve
1210-2a Alignment Examples
1210-2b Alignment Examples
1210-2c Alignment Examples
1220-1 Grade Length
1220-2a Coordination of Horizontal and Vertical Alignments
1220-2b Coordination of Horizontal and Vertical Alignments
1220-2c Coordination of Horizontal and Vertical Alignments
1220-3 Grading at Railroad Crossings
1230-1 Geometric Cross Section - Guide to Chapters
1230-2 State and City Jurisdictional Responsibilities

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Exhibits

1231-1 Lane Widths for Highways

1231-2 Lane Width Considerations
1231-3 Motor Vehicle Oriented Cross Sections
1231-4 Cross Sections Featuring Bicycle Facilities
1231-5 Cross Sections Featuring Pedestrian Facilities
1231-6 Cross Sections Featuring Transit Facilities
1231-7 Complete Street Cross Sections
1232-1 Geometric Cross Section - Interstate (4 lanes shown, can vary)
1232-2 Geometric Cross Section – Non-Interstate (4 lanes shown, can vary)
1232-3 Median Section without Median Barrier
1238-1 Zones within the Streetside
1239-1 Shoulder Widths for Highways
1239-2 Shoulder Function & Modal Accommodation Width Considerations
1239-3 Shoulder Details
1239-3 Shoulder Details (continued)
1239-4 Drainage Ditch Details
1239-5a Bridge End Slopes
1239-5b Bridge End Slope Details
1239-6 Roadway Sections in Rock Cuts: Design A
1239-7 Roadway Sections in Rock Cuts: Design B
1239-8 Stepped Slope Design
1239-9 Minimum Lateral Clearance to Barrier and Curb
1239-10 Median Functions and Guidance: High and Intermediate Speeds
1239-11 Median Functions and Guidance: Low and Intermediate Speeds
1239-12a Divided Highway Median Sections
1239-12b Divided Highway Median Sections
1239-12c Divided Highway Median Sections
1240-1a Traveled Way Width for Two-Lane Two-Way Turning Roadways
1240-1b Traveled Way Width for Two-Lane Two-Way Turning Roadways: Based on the
Delta Angle
1240-2a Traveled Way Width for Two-Lane One-Way Turning Roadways
1240-2b Traveled Way Width for Two-Lane One-Way Turning Roadways: Based on the
Delta Angle
1240-3a Traveled Way Width for One-Lane Turning Roadways
Traveled Way Width for One-Lane Turning Roadways: Based on the Delta Angle,
1240-3b
Radius on Outside Edge of Traveled Way
1240-3c Traveled Way Width for One-Lane Turning Roadways: Based on the Delta Angle,
Radius on Inside Edge of Traveled Way
1250-1 Minimum Radius for Normal Crown Section
1250-2 Minimum Radius for Existing Curves

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 Exhibits

1250-3 Side Friction Factor

1250-4a Superelevation Rates (10% Max)
1250-4b Superelevation Rates (8% Max)
1250-4c Superelevation Rates (6% Max)
1250-5 Superelevation Rates for Intersections and Low-Speed Urban Roadways
1250-6a Superelevation Transitions for Highway Curves
1250-6b Superelevation Transitions for Highway Curves
1250-6c Superelevation Transitions for Highway Curves
1250-6d Superelevation Transitions for Highway Curves
1250-6e Superelevation Transitions for Highway Curves
1250-7a Superelevation Transitions for Ramp Curves
1250-7b Superelevation Transitions for Ramp Curves
1260-1 Design Stopping Sight Distance
1260-2 Design Stopping Sight Distance on Grades
1260-3 Stopping Sight Distance on Grades
1260-4 Stopping Sight Distance: Crest Vertical Curves
1260-5 Sight Distance: Crest Vertical Curve
1260-6 Stopping Sight Distance for Sag Vertical Curves
1260-7 Sight Distance: Sag Vertical Curve
1260-8 Horizontal Stopping Sight Distance
1260-9 Sight Distance: Horizontal Curves
1260-10 Sight Distance: Overlapping Horizontal and Crest Vertical Curves
1260-11 Existing Stopping Sight Distance
1260-12 Passing Sight Distance
1260-13 Passing Sight Distance: Crest Vertical Curve Calculations
1260-14 Passing Sight Distance: Crest Vertical Curves
1260-15 Decision Sight Distance
1270-1 Climbing Lane Example
1270-2a Speed Reduction Warrant: Performance for Trucks
1270-2b Speed Reduction Warrant Example
1270-3 Auxiliary Climbing Lane
1270-4 Passing Lane Example
1270-5 Length of Passing Lanes
1270-6 Passing Lane Configurations
1270-7 Buffer Between Opposing Passing Lanes
1270-8 Auxiliary Passing Lane
1270-9 Emergency Escape Ramp Example
1270-10 Emergency Escape Ramp Length
1270-11 Rolling Resistance (R)

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Exhibits

1270-12 Typical Emergency Escape Ramp

1270-13 Chain Up/Chain Off Area
1300-1 Intersection Design Considerations
1300-2 Median U-Turn Intersection Example
1300-3 Restricted Crossing U-Turn Intersection Example with Stop-control
1300-4 Displaced Left Turn Intersection Example
1310-1 Lane Alignment Taper Rate
1310-2 Ramp Terminal Intersection Details
1310-3 Median at Two-Way Ramp Terminal
1310-4 Intersection Balance Example
1310-5 Diamond Interchange With Advance Storage
1310-6 Initial Ranges for Right-Turn Corner (Simple Curve-Taper)
1310-7a Left-Turn Storage Guidelines: Two-Lane, Unsignalized
1310-7b Left-Turn Storage Guidelines: Four-Lane, Unsignalized
1310-8a Left-Turn Storage Length: Two-Lane, Unsignalized (40 mph)
1310-8b Left-Turn Storage Length: Two-Lane, Unsignalized (50 mph)
1310-8c Left-Turn Storage Length: Two-Lane, Unsignalized (60 mph)
1310-9 Left-Turn Storage With Trucks (ft)
1310-10a Median Channelization: Widening
1310-10b Median Channelization: Median Width 11 ft or More
1310-10c Median Channelization: Median Width 23 ft to 26 ft
1310-10d Median Channelization: Median Width of More Than 26 ft
1310-10e Median Channelization: Minimum Protected Storage
1310-10f Median Channelization: Two-Way Left-Turn Lane
1310-11 Right-Turn Lane Guidelines
1310-12 Right-Turn Pocket and Right-Turn Taper
1310-13 Right-Turn Lane
1310-14 Acceleration Lane
1310-15a Traffic Island Designs
1310-15b Traffic Island Designs: Compound Curve
1310-15c Traffic Island Designs
1310-16 U-Turn Spacing
1310-17 U-Turn Roadway
1310-18 U-Turn Median Openings
1310-19a Sight Distance at Intersections
1310-19b Sight Distance at Intersections
1320-1 Suggested Initial Design Ranges
1320-2 Radii-Speed Relationship on Approach Legs and R Value Relationships
1320-3 Intersection Sight Distance

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 Exhibits

1330-1 Responsibility for Facilities

1330-2 Example Continuous Green “T” (CGT) Intersection Layout
1330-3 Left-Turn Lane Configuration Examples
1330-4 Recommended Features for Intersections Near Rail Crossings
1330-5 Standard Intersection Movements, Head Numbers, and Phase Operation
1330-6 Detector Numbering Examples
1330-7a Signal Display Placements – Key to Diagrams
1330-7b Signal Displays for Single Lane Approach
1330-7c Signal Display Mounting Locations for Multi-Lane Approaches
1330-7d Signal Displays for Dedicated Left Turn Lanes
1330-7e Signal Displays for Shared Through-Left Lanes – Multiple Through Lanes
1330-7f Signal Displays for Shared Through-Right Lanes
1330-7g Signal Displays for Dedicated Right Turn Lanes
1330-7h Signal Displays for Multiple Turn Lanes
1330-8 Example Signal Display Placement for Skew Intersection
1330-9 Signal Display Maximum Heights
1330-10 Pedestrian Display Placement Requirements
1330-11 PPB Placement Requirements
1330-12a PPB Placement on Vertical Shaft Poles
1330-12b PPB Placement on Large Signal Standards
1330-13 Signal Display Surface Areas
1330-14 Timber Strain Pole Classes
1330-15 Fixed Vehicle Detection Placement
1330-16 Decision Zone Detection Placement
1330-17 Video Detector Placement
1330-18 Signal Display Layout for Rail Crossings
1330-19 Conduit and Conductor Sizes
1330-20 Phase Diagrams: Four-Way Intersections
1330-21 Phase Diagrams: Three-Way Intersections
1330-22 Phasing at Railroad Crossings
1340-1 Driveway Design Template SU-30 and Smaller
1340-2 Driveway Design Template SU-30 and Larger
1340-3 Driveway Sight Distance
1350-1 Sight Distance at Railroad Crossing
1350-2 Typical Pullout Lane at Railroad Crossing
1360-1 Basic Interchange Patterns
1360-2 Interchange Spacing
1360-3 Minimum Ramp Connection Spacing
1360-4 Ramp Design Speed

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Exhibits

1360-5 Maximum Ramp Grade

1360-6 Ramp Widths
1360-7a Lane Balance
1360-7b Lane Balance
1360-8 Main Line Lane Reduction Alternatives
1360-9 Acceleration Lane Length
1360-10 Deceleration Lane Length
1360-11a Gore Area Characteristics
1360-11b Gore Area Characteristics
1360-12 Length of Weaving Sections
1360-13a On-Connection: Single-Lane, Tapered
1360-13b On-Connection: Single-Lane, Parallel
1360-13c On-Connection: Two-Lane, Parallel
1360-13d On-Connection: Two-Lane, Tapered
1360-14a Off-Connection: Single-Lane, Tapered
1360-14b Off-Connection: Single-Lane, Parallel
1360-14c Off-Connection: Single-Lane, One-Lane Reduction
1360-14d Off-Connection: Two-Lane, Tapered
1360-14e Off-Connection: Two-Lane, Parallel
1360-15a Collector-Distributor: Outer Separations
1360-15b Collector Distributor: Off-Connections
1360-15c Collector Distributor: On-Connections
1360-16 Loop Ramp Connections
1360-17 Temporary Ramps
1360-18 Interchange Plan
1410-1 Minimum Traveled Way Widths for Articulated Buses
1410-2 Typical HOV Lane Sections
1410-3 Roadway Widths for Two-Lane Ramps With an HOV Lane
1410-4a Single-Lane Ramp Meter With HOV Bypass
1410-4b Two-Lane Ramp Meter With HOV Bypass
1410-5a Enforcement Area: One Direction Only
1410-5b Enforcement Area: Median
1430-1 Bus Zone Dimensions
1430-2 Pullout for Bus Stop along a Road
1430-3 Bus Stop Pullouts: Arterial Streets
1430-4 Bus Zone and Pullout After Right Turn
1430-5 Bus Stop Accessibility Features
1430-6 Bus Berth Design
1430-7 Design Alternative for a Combination of Bus Berths at a Platform

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 Exhibits

1510-1 Pedestrian Circulation Paths

1510-2 Relationship Between Pedestrian Circulation Paths and Pedestrian Access Routes
1510-3 Obstructed Pedestrian Access Route
1510-4 Beveling Options
1510-5 Surface Discontinuities (Noncompliant)
1510-6 Sidewalks With Buffers
1510-7 Typical Sidewalk Designs
1510-8 Typical Driveways
1510-9 Perpendicular Curb Ramp
1510-10 Perpendicular Curb Ramp Common Elements
1510-11 Parallel Curb Ramp
1510-12 Parallel Curb Ramp Common Elements
1510-13 Combination Curb Ramp
1510-14 Typical Curb Ramp Drainage
1510-15 Unmarked Crosswalks
1510-16 Marked Pedestrian Crossing
1510-17 Vacant
1510-18 Midblock Pedestrian Crossing
1510-19 Obstructed Line of Sight at Intersection
1510-20 Improved Line of Sight at Intersection
1510-21 Curb Extension Examples
1510-22 Raised Islands With Curb Ramps and Pedestrian Cut-Throughs
1510-23 Clear Space for Pedestrian Pushbutton
1510-24a Perpendicular Ramp Concurrent Clear Space Examples
1510-24b Parallel Ramp Concurrent Clear Space Examples
1510-25 Reach Range for Pedestrian Pushbutton
1510-26 Pedestrian Railroad Crossings
1510-27 Pedestrian Railroad Warning Device
1510-28 Pedestrian Bridges
1510-29 Pedestrian Tunnel
1510-30 Access Ramp With Accessible Handrails
1510-31 Work Zones and Pedestrian Facilities
1515-1 Shared-Use Path
1515-2 Bicycle Design Speeds
1515-3 Two-Way Shared-Use Path: Independent Alignment
1515-4a Two-Way Shared-Use Path: Adjacent to Roadway (≤ 35 mph)
1515-4b Two-Way Shared-Use Path: Adjacent to Roadway (> 35 mph)
1515-5 Shared-Use Path Side Slopes and Railing
1515-6 Shared-Use Path Landing Profile

WSDOT Design Manual M 22-01.18 Page 23

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Exhibits

1515-7 Shared-Use Path Landing and Rest Area

1515-8 Typical Redesign of a Diagonal Midblock Crossing
1515-9 Adjacent Shared-Use Path Intersection
1515-10 Roadway Crossing Refuge Area
1515-11 Shared-Use Path Bridge and Approach Walls
1515-12 Bridge and Pedestrian Rail
1515-13 Shared-Use Path in Limited Access Corridor
1515-14a Stopping Sight Distance for Downgrades
1515-14b Stopping Sight Distance for Upgrades
1515-15 Minimum Lengths for Crest Vertical Curves
1515-16 Lateral Clearance for Horizontal Curves
1520-1 Raised and Curb-Separated Bike Facility
1520-2 Separated Buffered Bike Lane
1520-3 Buffered Bike Lane
1520-4 Bike Lane
1520-5 Shared Lane Markings
1520-6a Bicycle Facility Selection Chart – Interested, but Concerned Cyclists
1520-6b Bicycle Facility Selection Chart – Confident Cyclists
1520-7 Approach Through Lanes
1520-8 Bike Box and Intersection Crossing Markings
1520-9 Two-Stage Left-Turn Queue Box
1520-10 Median Refuge Island for Cyclists
1520-11 Length of Solid Green Pavement Marking Preceding Conflict Area
1520-12 At-Grade Railroad Crossings
1520-13 Barrier Adjacent to Bicycle Facilities
1520-14a Bike Facility Crossing On and Off Ramps
1520-14b Bicycle Facility Crossing Single Lane On Ramp
1520-14c Bicycle Facility Crossing Option for Dual Lane On-Ramp Configuration
1520-14d Bicycle Facility Crossing Option for Dual Off-Ramp
1600-1 City and State Responsibilities and Jurisdictions
1600-2 Design Clear Zone Distance Table
1600-3 Design Clear Zone Inventory Form Link to Website for the form
1600-4 Recovery Area
1600-5 Design Clear Zone for Ditch Sections
1600-6 Guidelines for Embankment Barrier
1600-7 Mailbox Location and Turnout Design
1600-8 Glare Screens
1610-1 Concrete Barrier Placement Guidance: Assessing Impacts to Wildlife
1610-2 Traffic Barrier Locations on Slopes

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 Exhibits

1610-3 Longitudinal Barrier Deflection

1610-4 Longitudinal Barrier Flare Rates
1610-5 Barrier Length of Need on Tangent Sections
1610-6 Barrier Length of Need
1610-7 Barrier Length of Need on Curves
1610-8 W-Beam Guardrail Trailing End Placement for Divided Highways
1610-9 Beam Guardrail Post Installation
1610-10 Guardrail Connections
1610-11 Transitions and Connections
1610-12 Median Cable Barrier Placement
1610-13a Roadside Cable Barrier Placement
1610-13b Cable Barrier Placement for Divided Highways
1610-14 Concrete Barrier Shapes
1610-15 Type 7 Bridge Rail Upgrade Criteria
1610-16 Thrie Beam Rail Retrofit Criteria
1620-1 Impact Attenuator Distance Beyond Length of Need
1710-1 WSDOT Safety Rest Area
1710-2 WSDOT’s SRA Project and Programming Roles
1710-3 Additional Safety Rest Area Resources
1710-4 Roadside Facilities Level of Development
1710-5 Typical Truck Storage
1710-6 WSDOT Safety Rest Area Building – Adaptive Reuse Historic Preservation
1720-1 Truck Weigh Site: Multilane Highways
1720-2 Truck Weigh Site: Two-Lane Highways
1720-3 Vehicle Inspection Installation
1720-4 Minor Portable Scale Site
1720-5 Major Portable Scale Site
1720-6 Small Shoulder Site
1720-7 Large Shoulder Site
1720-8 MOU Related to Vehicle Weighing and Equipment: Inspection Facilities on
State Highways

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Chapter 100 Manual Description
100.01 Purpose
100.02 Presentation and Revisions
100.03 Practical Solutions
100.04 Manual Applications
100.05 Manual Use
100.06 Manual Organization

100.01 Purpose
WSDOT has developed the Design Manual to reflect policy, outline a uniformity of methods and
procedures, and communicate vital information to its employees and others who develop
projects on state highways. When properly used, the manual will facilitate the development of a
highway system consistent with the needs of the multimodal traveling public.

WSDOT designers are required to comply with the Design Manual. The Federal Highway
Administration (FHWA) has agreed to approve designs that follow guidance in the Design
Manual; therefore, adherence to the guidance presented is not optional for state highway
projects.

The information, guidance, and references contained herein are not intended as a substitute
for sound engineering judgment. The Design Manual is not a comprehensive textbook on
highway engineering, nor does it attempt to cover all the possible scenarios Washington’s
highways present. It is recognized that some situations encountered are beyond the scope
of this presentation.

If you have design questions not answered by the Design Manual, contact the Headquarters
(HQ) Design Office.

100.02 Presentation and Revisions

The Design Manual is available on the Internet. It can be accessed through the:
• WSDOT Home Page:
 www.wsdot.wa.gov/
• Design Policy Web Page:
 www.wsdot.wa.gov/design/policy/
• Active Design Manual Revisions Web Page:
 www.wsdot.wa.gov/design/manual/activerevisions.htm
• Publications Services Web Page:
 www.wsdot.wa.gov/publications/manuals/index.htm

The online version of the manual enables you to conduct a word search of the entire manual.
Opening an individual chapter is faster, but a word search is limited to that chapter.

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Manual Description Chapter 100

The Design Manual is continually revised to reflect changing processes, procedures, regulations,
policies, and organizations. Feedback from users is encouraged to improve the manual for
everyone. Comments may be submitted by any method that is convenient for you. There is
a comment form in the front of the manual, or comments may be made via the contact names
on the Design Policy Internet page (see link above). Note that the Design Policy Internet page
includes a link to an errata page, which provides a list of known technical errors in the manual.
Manual users are encouraged to view this page on a regular basis.

A contents section lists all chapters and the major headings of the sections/pages. The exhibits
section lists all the exhibits in the manual.

Most chapters include a list of references, including laws, administrative codes, manuals, and
other publications, which are the basis for the information in the chapter. The definitions for
terms used in the Design Manual are found in the Glossary.

100.03 Practical Solutions

WSDOT deploys Practical Solutions to enable more flexible and sustainable transportation
investment decisions. It encourages this by: (1) increasing the focus on addressing identified
performance gaps (needs) throughout all phases of development, and (2) engaging local
stakeholders at the earliest stages of scope definition to ensure their input is included at the
right stage of the solution development process. Practical Solutions includes one or a
combination of strategies, including, but not limited to, operational improvements, off-system
solutions, transportation demand management, and incremental strategic capital solutions. (See
Chapter 1100 for more information.)

100.04 Manual Applications

Design Manual guidance is provided to encourage the statewide uniform application of design
details under normal conditions. It also guides designers through the project development
process used by WSDOT. The Design Manual is used by the department to:
• Interpret current design principles, including American Association of State Highway
and Transportation Officials (AASHTO) and other appropriate policy sources, findings,
and federal and state laws.
• Develop projects that address modal and community performance needs.
• Balance the competing performance needs of highway construction projects.
• Design for low-cost solutions.

The Design Manual is designed to allow for flexibility in design for specific and unusual
situations. For unusual circumstances, the manual provides mechanisms for documenting
the reasons for the choices made.

The Design Manual is developed for use on Interstate and state highways and may not
be suitable for projects on county roads or city streets.

100.05 Manual Use

The WSDOT Design Manual is intended to be used for design of department-owned facilities,
especially the transportation facilities associated with state highways as designated by RCW
47.17.

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Chapter 100 Manual Description

For state highway routes, projects are designed using the Design Manual practical design
approach (see Chapter 1100 and Division 11). If WSDOT guidance is not used on a project,
appropriate documentation and approvals are required (see Chapters 300 and 1100).

When WSDOT designs facilities that will be turned over to local jurisdictions, those facilities
are to be designed using appropriate local geometric design criteria.

When local jurisdictions design any element of state highway facilities, the Design Manual must
be used. Local jurisdictions are free to adopt this manual for their local criteria or to develop
their own specialized guidance for facilities not on state highway routes.

100.06 Manual Organization

The Design Manual is divided into a series of divisions that address a portion of the project
development and design processes. The divisions are composed of chapters that address
the general topic in detail and are, in some cases, specific to a particular discipline.

Division 1 – General Information: Presents an overview of the Design Manual, its contents and
application, as well as a chapter on Design-Build projects.
• Chapter 100 – Manual Description: Chapter content/resources within the Design
Manual.
• Chapter 110 – Design-Build Projects: How the Design Manual applies to design-build
projects: includes terminology and reference to design-build contract documents.

Division 2 – Hearings, Environmental, and Permits: Provides the designer with information
about the public involvement and hearings process, the environmental documentation process,
and the permit process.
• Chapter 210 – Public Involvement and Hearings: Developing a project-specific public
involvement plan; the ingredients of an effective public involvement plan; and methods
for public involvement.
• Chapter 225 – Environmental Coordination: Provides a summary of the relevant
provisions in the Environmental Manual. Gives designers a brief overview and direction
to environmental resources.

Division 3 – Project Documentation: Provides designers with information on project

management, value engineering, traffic and safety analysis, design documentation, and
approvals.
• Chapter 300 – Design Documentation, Approval, and Process Review: Building the
Project File (PF) and the Design Documentation Package (DDP) and recording the
recommendations and decisions that lead to a project by preserving the documents
from the planning, scoping, programming, and design phases (includes permits,
approvals, contracts, utility relocation, right of way, advertisement and award, and
construction). Links to websites to download documentation templates.

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Manual Description Chapter 100

• Chapter 301 – Design and Maintenance Coordination – Best Practices: Means and
methods for coordinating design with maintenance concerns and needs.
• Chapter 305 – Project Management: Brief description and links to WSDOT project
management resources.
• Chapter 310 – Value Engineering: A systematic, multidisciplinary process study early in
the project design stage to provide recommendations to improve scope, functional
design, constructability, environmental impacts, or project cost—required by federal
law for high-cost, complex projects.
• Chapter 320 – Traffic Analysis: Procedural guidance and general requirements for
conducting traffic analyses.
• Chapter 321 – Sustainable Safety Analysis: Informational and procedural guidance for
conducting safety analyses, within the current extent of the applications.
Division 4 – Surveying: Includes criteria for surveying, mapping, and monumentation
requirements.
• Chapter 400 – Surveying and Mapping: The procedures within WSDOT for project
surveying.
• Chapter 410 – Monumentation: The requirements and procedures for Monumentation.

Division 5 – Right of Way and Access Control: Provides guidance on right of way considerations;
access revision report; limited/managed access; and fencing.
• Chapter 510 – Right of Way Considerations: The right of way and easement acquisition
process.
• Chapter 520 – Access Control: WSDOT Access Control program information.
• Chapter 530 – Limited Access Control: Clarification on full, partial, and modified limited
access control.
• Chapter 540 – Managed Access Control: The classes of managed access highways and
the access connection permitting process.
• Chapter 550 – Freeway Access Revision: The process for interchange access revisions on
freeways and the steps for producing an access revision report.
• Chapter 560 – Fencing: The purpose of fencing, types of fencing, and fencing design
criteria.

Division 6 – Soils and Paving: Presents guidance for investigating soils, rock, and surfacing
materials; estimating tables; and guidance and criteria for the use of geosynthetics.
• Chapter 610 – Investigation of Soils, Rock, and Surfacing Materials: The requirements
for qualifying a materials source, geotechnical investigations, and the documentation
to be included in the Project File.
• Chapter 620 – Design of Pavement Structures: Estimating tables for the design of
pavement structures.
• Chapter 630 – Geosynthetics: The types/applications of geosynthetic drainage,
earthwork, erosion control, and soil reinforcement materials.

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Chapter 100 Manual Description

Division 7 – Structures: Provides guidance for the design of structures for highway projects,
including site data for structures, bridges, retaining walls, and noise walls.
• Chapter 700 – Project Development Roles and Responsibilities for Projects With
Structures: WSDOT’s project development process: roles and responsibilities for
projects with structures during the project development phase of a project.
• Chapter 710 – Site Data for Structures: Information required by the HQ Bridge and
Structures Office to provide structural design services.
• Chapter 720 – Bridges: Basic design considerations for developing preliminary bridge
plans and guidelines on basic bridge geometric features.
• Chapter 730 – Retaining Walls and Steep Reinforced Slopes: Design principles,
requirements, and guidelines for retaining walls and steep reinforced slopes.
• Chapter 740 – Noise Barriers: Factors considered when designing a noise barrier.

Division 8 – Hydraulics: Addresses the issue of hydraulics and serves as a guide to highway
designers to identify and consider hydraulic-related factors that may impact the design.
• Chapter 800 – Hydraulic Design: Hydraulic considerations for highway projects involving
flood plains, stream crossings, channel changes, and groundwater.

Division 9 – Roadside Development: Provides guidance on the portion of state highways

between the traveled way and the right of way boundary.
• Chapter 900 – Roadside Development: Managing the roadside environment, including
the area between the traveled way and the right of way boundary, unpaved median
strips, and auxiliary facilities such as rest areas, wetlands, and stormwater treatment
facilities.
• Chapter 950 – Public Art: Policies and procedures for including public art in state
transportation corridors.

Division 10 – Traffic Safety Elements: Introduces the designer to traffic safety elements such as
work zone traffic control, signing, delineation, illumination, traffic control signals, and Intelligent
Transportation Systems (ITS).
• Chapter 1010 – Work Zone Safety and Mobility: Planning, design, and preparation
of highway project plans that address work zone safety and mobility requirements.
• Chapter 1020 – Signing: The use of signing to regulate, warn, and guide motorists.
• Chapter 1030 – Delineation: The use of pavement markings to designate safe traffic
movement.
• Chapter 1040 – Illumination: Illumination design on state highway construction
projects.
• Chapter 1050 – Intelligent Transportation Systems (ITS): Applying computer and
communication technology to optimize the safety and efficiency of the highway system.

Division 11 – Practical Design: Provides practical design guidance for WSDOT projects.
• Chapter 1100 – Practical Design: Includes an overview and description of the WSDOT
Practical Solutions initiative, the practical design process, and the relevant chapter
information necessary to complete each process step.

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Manual Description Chapter 100

• Chapter 1101 – Need Identification: Includes guidance on accurate and concise

identification of project needs for practical design.
• Chapter 1102 – Context Identification: Guidance provided to help determine the
highway’s land use context and transportation context.
• Chapter 1103 – Design Control Selection: Provides guidance on design controls used in
WSDOT projects.
• Chapter 1104 – Alternatives Analysis: Discusses how information determined from
planning phases and Design Manual chapters is utilized in alternative solution
formation, and how to evaluate the alternative solutions developed.
• Chapter 1105 – Design Element Selection: Provides guidance on selecting design
elements for projects.
• Chapter 1106 – Design Element Dimensions: Discusses the practical design approach
to selecting design element dimensions.
• Chapter 1120 – Preservation Projects: Provides scoping links and elements and features
to be evaluated in preservation projects.

Division 12 – Geometrics: Covers geometric plan elements; horizontal alignment; lane

configurations and pavement transitions; geometric profile elements; vertical alignment;
geometric cross sections; and sight distance.
• Chapter 1210 – Geometric Plan Elements: The design of horizontal alignment, lane
configuration, and pavement transitions.
• Chapter 1220 – Geometric Profile Elements: The design of vertical alignment.
• Chapter 1230 – Geometric Cross Section – Basics: Roadway cross section introductory
chapter; guide to other cross section chapters; provides jurisdictional guidance.
• Chapter 1231 – Geometric Cross Section – Highways: Geometric cross section guidance
for all highways except freeways.
• Chapter 1232 – Geometric Cross Section – Freeways: cross section guidance for
freeways and Interstates.
• Chapter 1238 – Geometric Cross Section – Streetside and Parking: provides information
on parking and streetside elements.
• Chapter 1239 – Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians:
Provides information on geometric cross section components common to many facility
types. Cross section elements include: shoulders, medians and outer separations, side
slopes, and curbing
• Chapter 1240 – Turning Roadways: Widening curves to make the operating conditions
comparable to those on tangent sections.
• Chapter 1250 – Cross Slope and Superelevation: Cross slope design information is
provided as well as superelevating curves and ramps so design speeds
can be maintained.
• Chapter 1260 – Sight Distance: Stopping, passing, and decision sight distance design
elements.

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Chapter 100 Manual Description

• Chapter 1270 – Auxiliary Lanes: Auxiliary facilities such as climbing lanes, passing lanes,
slow-vehicle turnouts, shoulder driving for slow vehicles, emergency escape ramps, and
chain-up areas.

Division 13 – Intersections and Interchanges: Addresses the design considerations of at-grade

intersections, roundabouts, road approaches, railroad grade crossings, and traffic interchanges.
• Chapter 1300 – Intersection Control Type: Guidance on preliminary intersection
evaluation and selection of control type.
• Chapter 1310 – Intersections: Designing intersections at grade, including at-grade
ramp terminals.
• Chapter 1320 – Roundabouts: Guidance on the design of roundabouts.
• Chapter 1330 – Traffic Control Signals: The use of power-operated traffic control
devices that warn or direct traffic.
• Chapter 1340 – Driveways: The application and design of road approaches on state
highways.
• Chapter 1350 – Railroad Grade Crossings: The requirements for highways that cross
railroads.
• Chapter 1360 – Traffic Interchanges: The design of interchanges on interstate highways,
freeways, and other multilane divided routes.
• Chapter 1370 – Median Crossovers: Guidance on locating and designing median
crossovers for use by maintenance, traffic service, emergency, and law enforcement
vehicles.

Division 14 – HOV and Transit: Provides design guidance on HOV lanes and transit facilities.
• Chapter 1410 – High-Occupancy Vehicle Facilities: Evaluating and designing high-
occupancy vehicle (HOV) facilities.
• Chapter 1420 – HOV Direct Access: Design guidance on left-side direct access to HOV
lanes and transit facilities.
• Chapter 1430 – Transit Facilities: Operational guidance and information for designing
transit facilities such as park & ride lots, transfer/ transit centers, and bus stops and
pullouts.

Division 15 – Pedestrian and Bicycle Facilities: Provides guidance on pedestrian and bicycle
facility design.
• Chapter 1510 – Pedestrian Facilities: Designing facilities that encourage efficient
pedestrian access that meets ADA.
• Chapter 1515 – Shared-Use Paths: Guidance that emphasizes pedestrians are users
of shared-use paths and accessibility requirements apply in their design.
• Chapter 1520 – Roadway Bicycle Facilities: Selecting and designing useful and cost-
effective bicycle facilities.

Division 16 – Roadside Safety Elements: Addresses design considerations for the area outside
the roadway, and includes clear zone, roadside, safety mitigation, traffic barriers, and impact
attenuator systems.

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Manual Description Chapter 100

• Chapter 1600 – Roadside Safety: Clear zone and roadside design, mitigation guidance,
and roadside safety features, including Rumble Strips.
• Chapter 1610 – Traffic Barriers: Design of traffic barriers.
• Chapter 1620 – Impact Attenuator Systems: Permanent and work zone impact
attenuator systems.

Division 17 – Roadside Facilities: Provides design guidance for the area outside the roadway,
including rest areas and truck weigh sites.
• Chapter 1710 – Safety Rest Areas and Traveler Services: Typical layouts for safety rest
areas.
• Chapter 1720 – Weigh Sites: Guidance on designing permanent, portable, and shoulder-
sited weigh sites.

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Chapter 110 Design-Build Projects
110.01 General
110.02 Terminology and Language Used
110.03 Design and Documentation Responsibility
110.04 References

110.01 General
This chapter emphasizes that the Design Manual applies to the delivery methods of all
Washington State Department of Transportation (WSDOT) capital projects, including design-
build projects. Certain terms are defined to coincide with WSDOT design-build project delivery;
however, it is beyond the scope of this manual to extensively define design-build projects.
Design-build projects are based on their own contractual documents (such as a Request for
Proposal), which present directive language intended to legally define the project and identify
requirements and controls, roles and responsibilities, and procedures and outcomes.

Design-build is a method of project delivery in which WSDOT executes a single contract with one
entity (the design-builder) for design and construction services to provide a finished product. In
a traditional WSDOT design-bid-build contract, the design process is completed independent of
the construction contract. Under WSDOT policy, the Basis of Design (see Chapters 1100 and 300)
is approved prior to issuing an RFP.

Delivering a project using design-build contracting eliminates very few steps when compared to
the typical WSDOT design-bid-build process. The same project work tasks and products are
normally required whether performed by WSDOT or the design-builder. The timing, order, and
level of task detail performed are what make design-build contracting different than design-bid-
build. The design-build process may shift many tasks and responsibilities from WSDOT to the
design-builder depending on the project’s scope/risk analysis. The shift changes the order and
development detail of the tasks and thus must be reflected in the process through contractual
documents.

According to state law, to be considered for design-build designation in Washington State, a

project must be greater than $2 million and provide the opportunity for one of the following:
 Highly specialized construction activities requiring significant input into the design.
 Greater innovation and efficiencies between the designer and the builder.
 Significant savings in project delivery time.

110.02 Terminology and Language Used

110.02(1) Application of Terminology

Several terms are encountered throughout the Design Manual that are not normally applicable
to design-build project delivery. They are expanded in this chapter to provide appropriate
meaning for design-build projects and design-build personnel. It is intended that design-build
personnel acknowledge these expanded meanings and apply them throughout the manual,
which will eliminate the need to restate them each time they are encountered.

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Design-Build Projects Chapter 110

design-builder The firm, partnership, joint venture, or organization that contracts with WSDOT
to perform the work.

designer This term applies to WSDOT design personnel. Wherever “designer” appears in
this manual, design-build personnel shall deem it to mean: Engineer of Record, Design Quality
Assurance Manager, design-builder, or any other term used in the design-build contract to
indicate design-build personnel responsible for the design elements of a design-build project,
depending on the context of information being conveyed.

Project Engineer This term applies to WSDOT personnel. Wherever “Project Engineer” appears
in this manual, the design-builder shall deem it to mean “Engineer of Record.”

Request for Proposal (RFP) The document package issued by WSDOT requesting submittal of
proposals for the project and providing information relevant to the preparation and submittal of
proposals, including the instructions to proposers, contract documents, bidding procedures, and
reference documents.

Additional terms are presented in the Design Manual Glossary.

110.02(2) Language Used for Design Flexibility

The Design Manual is primarily written for WSDOT engineering personnel; however, design-
builders, local agencies, and developers also use it for state and local agency projects. Under
WSDOT practical design, flexibility is encouraged to develop independent designs tailored to
context and identified performance need. (See chapters in the 1100 series for more information
about practical design policy and guidance.)

With the exclusion of this chapter, the Design Manual is intentionally written to avoid or
minimize the use of directive words like “shall” and “should” in order to retain this important
flexibility for the larger set of users.

In the case of design-build projects, design flexibility applies to the extent allowed by the
contract. The design-builder shall refer to the project-specific RFP for design guidance. The RFP
will identify design decisions and provide technical specifications relating to the project’s design.

110.03 Design and Documentation Responsibility

In the traditional design-bid-build format, WSDOT bears the entire responsibility and risk for any
design-related issues. As the owner, all responsibility for design decisions and conformance to
standards rests with WSDOT.

For design-build projects, many design responsibilities shift to the design-builder once the
Notice to Proceed is issued. WSDOT is still responsible for establishing the scope, performance
measurements, and existing conditions of the site as part of preliminary design. Any preliminary
design done by WSDOT would be filed and documented in the Design Documentation Package
(DDP) and/or the Project File (PF), which are provided to the selected design-builder to maintain
throughout the design-build project design phase and then returned to WSDOT for retention.

It is important to note that the design content presented in this manual has valid application
based not on delivery method, but on practical design procedures and specified needs such as
roadway and land use context, traffic volumes, and identified performance needs, as presented
in Chapter 1100 (and other chapters).

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Chapter 110 Design-Build Projects

It is also important to specify that design documentation is a requirement for WSDOT projects,
regardless of delivery method. WSDOT still holds the valid requirement to have an organized
design documentation file and as-constructed plans for future reference after the project is
built.

Plan accuracy, conformance with established design guidelines, and constructability of the
project rests with the design-builder.

The DDP and the PF include all the elements identified in the project RFP. The RFP specifies
various DDP and PF submittals to WSDOT, identifying how each item will be submitted (report,
plan sheet element, Basis of Design and design parameter element, and so on) and who is
responsible for the development status (such as complete, in progress, or not started) of each
item. The RFP also indicates that some of the DDP and PF items have components that were
started by WSDOT and that the design-builder shall complete or update those item(s). It is the
design-builder’s responsibility to obtain copies of the information from WSDOT for use in
completing the DDP and PF items.

The DDP and the PF require retention of original, signed documents—not copies.

The RFP typically specifies that the design-builder shall provide WSDOT with updates to the DDP
and PF items throughout construction of the project.

For further guidance on design documentation and WSDOT acceptance thereof, see Chapter
300, the project RFP, and the Design Documentation Checklist.

110.04 References

110.04(1) Design-Build Guidance

The Design-Build Guidance Statements listed below are available at:
 www.wsdot.wa.gov/projects/delivery/designbuild/
 Design Quality Control, Quality Assurance, and Quality Verification on Design-Build
Projects
 Project Basic Configuration Development
 Use of Reference Documents on Design-Build Projects

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Design-Build Projects Chapter 110

Exhibit 110-1 Design Documentation Sequence for a Typical Design-Build Project

Design-Builder Delivers
WSDOT Begins Project Completed Documentation
Design Documentation
Documentation Package to WSDOT
Handoff to Design-Builder

Design Documentation Package

Project
Development
Project Ad
Project Award Approval

RFP Development Ad Period Design-Build Project Design

Package 1
Preliminary Design Submittal
Design Approval Final Design Submittal
Design Submittals are released in packages
Released for Construction Submittal by the Design-Builder to WSDOT
Project Scoping
Package 2
Preliminary Design Submittal
Final Design Submittal
Released for Construction Submittal

Package n
Preliminary Design Submittal
Final Design Submittal
Released for Construction Submittal
Project
Completion

Construction

Notes:
• The Design Documentation Package (DDP) is started by WSDOT during scoping/pre-RFP design. The design-builder completes the DDP as the
project proceeds.
• The design-builder shall refer to the RFP for specific review and approval processes. The RFP will specify procedures for design submittals,
including notifications to WSDOT and the time allowed for reviews.
• WSDOT will review design submittals for conformance with requirements of the contract.

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Chapter 210 Public Involvement and Hearings
210.01 General
210.02 References
210.03 Definitions
210.04 Public Involvement
210.05 Public Hearings
210.06 Environmental Hearing
210.07 Corridor Hearing
210.08 Design Hearing
210.09 Limited Access Hearing
210.10 Combined Hearings
210.11 Administrative Appeal Hearing
210.12 Follow-Up Hearing
210.13 Documentation

210.01 General
The Washington State Department of Transportation (WSDOT) strives to keep
the public informed about transportation issues, involve the public in transportation
decision making, and make transportation decisions based on the public’s
best interests.
One of the best ways to achieve WSDOT’s goals is to collaborate with the public,
community groups, and various agencies. These participants often have differing,
and sometimes conflicting, perspectives and interests. In addition, many participants
and organizations are not able to spend the time and effort required to fully engage
in transportation decision making. Despite these challenges, active collaboration:
• Gives WSDOT access to important information and new ideas.
• Puts us in a position to help solve problems and resolve conflicts.
• Creates a sense of community.
• Fosters greater acceptance of projects.
• Helps us build and sustain a credible and trusting relationship with the public.
• Ultimately leads to transportation improvements that better meet the public’s
needs and desires.
When collaborating with the public about transportation projects or issues, WSDOT
uses more formal techniques like public hearings, direct mail, and presentations to
city councils and legislators; as well as less formal but equally important techniques,
like telephone and e-mail discussions, meetings with community groups, media
relations, and project Internet pages.
Law requires that many types of capital transportation projects go through a formal
public hearing process; thus, the legal procedures necessary for public hearings is
the primary focus of this chapter. Public involvement plans are briefly discussed, and
referrals to WSDOT’s communications resources are included to further guide their
development and implementation.

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Public Involvement and Hearings Chapter 210

210.02 References
(1) Federal/State Laws and Codes
United States Code (USC) Title 23, Highways, Sec. 128, Public hearings
USC Title 23, Highways, Sec. 771.111, Early coordination, public involvement,
and project development
23 Code of Federal Regulations (CFR) 200.7, FHWA Title VI Policy
23 CFR 200.9(b)(4), Develop procedures for the collection of statistical data of
participants and beneficiaries of state highway programs
23 CFR 200.9(b)(12), Develop Title VI information for dissemination to the general
public
23 CFR 450.212, Public involvement
28 CFR Part 35, Nondiscrimination on the basis of disability in state and local
government services
49 CFR Part 27, Nondiscrimination on the basis of disability in programs or activities
receiving federal financial assistance
Americans with Disabilities Act of 1990 (ADA) (28 CFR Part 36, Appendix A)
Civil Rights Restoration Act of 1987
Executive Order 12898, Federal Actions to Address Environmental Justice in
Minority Populations and Low-Income Populations
Executive Order 13166, Improving Access to Services for Persons with Limited
English Proficiency
Revised Code of Washington (RCW) 47.50, Highway Access Management
RCW 47.52, Limited Access Facilities
Section 504 of the Rehabilitation Act of 1973, as amended
Title VI of the Civil Rights Act of 1964

(2) Design Guidance

Design Manual, Chapter 225, for environmental references, and Division 5 chapters
for access control and right of way references
Environmental Manual, M 31-11
 www.wsdot.wa.gov/publications/manuals/m31-11.htm
WSDOT Headquarters (HQ) Access and Hearings Section Manager, (360) 705-7266
home page:
 www.wsdot.wa.gov/design/accessandhearings

(3) Supporting Information

Improving the Effectiveness of Public Meetings and Hearings, Federal Highway
Administration (FHWA) Guidebook

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Chapter 210 Public Involvement and Hearings

Public Involvement Techniques for Transportation Decision-Making, FHWA

September 1996; provides tools and techniques for effective public involvement:
 www.fhwa.dot.gov/reports/pittd/cover.htm
Relocation brochures:  www.wsdot.wa.gov/realestate
WSDOT Communications Manual for public involvement:
 www.wsdot.wa.gov/communications/
WSDOT Context Sensitive Solutions Internet site and national context sensitive site:
 http://www.wsdot.wa.gov/design/policy/csdesign
 www.contextsensitivesolutions.org/

210.03 Definitions
affidavit of publication A notarized written declaration stating that a notice of
hearing (or notice of opportunity for a hearing) was published in the legally
prescribed manner.
affidavit of service by mailing A notarized written declaration stating that the
limited access hearing packet was mailed at least 15 days prior to the hearing and
entered into the record at the hearing.
auxiliary aids and services (1) Qualified interpreters, notetakers, transcription
services, written materials, telephone handset amplifiers, assistive listening devices,
assistive listening systems, telephones compatible with hearing aids, open and
closed captioning, telecommunications devices for deaf persons (TDDs), videotext
displays, or other effective methods for making aurally delivered materials available
to individuals with hearing limitations; (2) Qualified readers, taped texts, audio
recordings, Brailled materials, large print materials, or other effective methods for
making visually delivered materials available to individuals with visual impairments;
(3) Acquisition or modification of equipment or devices; (4) Other similar services
and actions; and (5) Providing and disseminating information, written materials,
and notices in languages other than English, where appropriate.
context sensitive solutions (CSS) A collaborative, interdisciplinary approach that
involves all stakeholders to develop a transportation facility that fits its physical *From “Understanding
Flexibility in
setting and preserves scenic, aesthetic, historic, and environmental resources while Transportation Design –
maintaining safety and mobility. CSS is an approach that considers the total context Washington,” WSDOT,
April 2005
within which a transportation improvement project will exist.* (See 210.02 and
210.04(2) for more information.)
court reporter A person with a license to write and issue official accounts of
judicial or legislative proceedings.
findings and order A document containing the findings and conclusions of a limited
access hearing approved by the Assistant Secretary, Engineering & Regional
Operations (see 210.09(12) and (13)).
hearing An assembly to which the public is invited and at which participation is
encouraged. Types of hearings include:
• administrative appeal hearing A formal process whereby a property owner
may appeal WSDOT’s implementation of access management legislation. The
appeal is heard by an administrative law judge (ALJ), who renders a decision.
(See Chapter 540 for administrative appeal hearing procedures.)

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Public Involvement and Hearings Chapter 210

• combined hearing A hearing held when there are public benefits to be gained
by combining environmental, corridor, design, and/or limited access subjects.
• corridor hearing A formal or informal hearing that presents the corridor
alternatives to the public for review and comment before a commitment is
made to any one route or location. This type of hearing is beneficial for existing
corridors with multiple Improvement projects programmed over a long duration.
• design hearing A formal or informal hearing that presents the design
alternatives to the public for review and comment before the selection of a
preferred alternative.
• environmental hearing A formal or informal hearing documenting that social,
economic, and environmental impacts have been considered and that public
opinion has been solicited.
• limited access hearing A formal hearing that gives local public officials,
owners of abutting properties, and other interested persons an opportunity to be
heard about the limitation of access to the highway system.
• formal hearing format A hearing conducted by a moderator using a formal
agenda, overseen by a hearing examiner, and recorded by a court reporter, as
required by law. Limited access hearings require the use of the formal hearing
format (see 210.05(3)).
• informal hearing format A hearing where oral comments are recorded by
a court reporter, as required by law. An informal hearing often uses the “open
house” format (see 210.04(1)(a)). A formal agenda and participation by a hearing
examiner are optional.
hearing agenda An outline of the actual public hearing elements, used with formal
hearings. (See 210.05(9)(a) for contents.)
Hearing Coordinator The HQ Access and Hearings Section Manager,
(360) 705-7266.
hearing examiner An administrative law judge from the Office of Administrative
Hearings, or a WSDOT designee, appointed to moderate a hearing.
hearing script A written document of text to be presented orally by department
representatives at a hearing.
hearing summary Documentation prepared by the region and approved by
Headquarters that summarizes environmental, corridor, and design hearings.
(See 210.05(10) for content requirements.)
hearing transcript A document prepared by the court reporter that transcribes
verbatim all oral statements made during the hearing, including public comments.
This document becomes part of the official hearing record.
NEPA National Environmental Policy Act.
notice of appearance A form provided by WSDOT for anyone wanting
to receive a copy of the findings and order and the adopted limited access plan
(see 210.09(3) and (8)).
notice of hearing (or hearing notice) A published advertisement that a public
hearing will be held.
notice of opportunity for a hearing An advertised offer to hold a public hearing.

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order of hearing The official establishment of a hearing date by the Director &
State Design Engineer, Development Division.
prehearing packet A concise, organized collection of all necessary prehearing data,
prepared by the region and approved by the HQ Access and Hearings Section
Manager prior to the hearing (see 210.05(4) and Exhibit 210-3).
project management plan A formal, approved document that defines how the project
is executed, monitored, and controlled. It may be in summary or detailed form and
may be composed of one or more subsidiary management plans and other planning
documents. For further information, see the Project Management Online Guide:
 http://www.wsdot.wa.gov/projects/projectmgmt/pmog.htm
public involvement plan A plan to collaboratively involve the public in decision
making, tailored to the specific needs and conditions of a project and the people and
communities it serves. It is often part of a broader communications plan.
relocation assistance program A program that establishes uniform procedures for
relocation assistance that will ensure legal entitlements and provide fair, equitable,
and consistent treatment to persons displaced by WSDOT-administered projects,
as defined in the Right of Way Manual.
résumé An official notification of action taken by WSDOT following adoption
of a findings and order (see 210.09(14)).
SEPA State Environmental Policy Act.
study plan A term associated with environmental procedures, this plan proposes
an outline or “road map” of the environmental process to be followed during the
development of a project that requires complex NEPA documentation. (See 210.06
and the Environmental Manual.)

210.04 Public Involvement

Developing and implementing an effective plan for collaboration with the public:
 Is critical to the success of WSDOT’s project delivery effort.
 Provides an opportunity to understand and achieve diverse community and
transportation goals.
Effective public involvement must begin with clearly defined, project-related goals
that focus on specific issues, specific kinds of input needed, and specific people or
groups that need to be involved. The more detailed a public involvement plan, the
greater its chances of obtaining information WSDOT can use in decision making.
Transportation projects with high visibility or community issues or effects often
attract the attention of a broad range of interested people. These types of projects
will best benefit from early public involvement, which can influence the project’s
success and community acceptance.
Developing a profile (through demographic analysis) of the affected community
is critical to achieving successful public involvement and should be the first order
of business when developing a public involvement plan. The profile will enable
the department to tailor its outreach efforts toward the abilities and needs of
the community.

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Public Involvement and Hearings Chapter 210

Individuals from minority and ethnic groups and low-income households, who are
traditionally underserved by transportation, often find participation difficult. While
these groups form a growing portion of the population, particularly in urban areas,
historically they have experienced barriers to participation in the public decision-
making process and are therefore underrepresented. These barriers arise from both
the historical nature of the public involvement process and from cultural, linguistic,
and economic differences. For example, a community made up of largely senior
citizens (with limited mobility/automobile usage) may mean:
• Meetings/open houses are planned in locations easily accessible to them, such
as senior centers and neighborhood community centers.
• Meetings are scheduled in the mornings or midday to accommodate individuals
who prefer not to leave home after dark.
• Meetings are scheduled in the evenings to accommodate persons who work
during the day.
A project’s affected area might consist of a population with limitations in speaking
or understanding English. This may entail:
• Developing/disseminating materials in other languages, as appropriate.
• Having a certified translator on hand at the meetings.
Extra effort may be needed to elicit involvement from people unaccustomed to
participating in the public involvement process. They often have different needs
and perspectives than those who traditionally participate in transportation decision
making, and they may have important, unspoken issues that should be heard. They
not only may have greater difficulty getting to jobs, schools, recreation, and shopping
than the population at large, but also they are often unaware of transportation
proposals that could dramatically change their lives.
NEPA and SEPA environmental policies and procedures are intended to provide
relevant environmental information to public officials, agencies, and citizens, and
allow public input to be considered before decisions are made. There are also various
other laws, regulations, and policies that emphasize public involvement, including
23 CFR, Title VI of the Civil Rights Act, the Americans with Disabilities Act, and
Executive Orders 12898 and 13166.
WSDOT’s collaborative process with the public should be open, honest, strategic,
consistent, inclusive, and continual. Initiating a project in an atmosphere of
collaboration and partnership can go a long way toward providing equal opportunities
for all parties (local, state, tribal, private, nonprofit, or federal) to participate in a
project vision. This collaboration requires an intensive communications effort that
is initiated during project visioning and extends through construction and eventual
operation of the facility.
Department specialists in public communications, environmental procedures,
traffic engineering, real estate services, and limited access control are routinely
involved with public outreach efforts and project hearings. Depending on the scale
and complexity of a project, the region is encouraged to engage the participation
of interdisciplinary experts when developing a public involvement plan and
communicating project details.

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Chapter 210 Public Involvement and Hearings

(1) Public Involvement Plan

The region develops a public involvement plan for its own use and guidance. To
engage the public, share the decision-making process, identify issues, and resolve
concerns, the region communicates with the affected community through group
presentations, open house meetings, newspaper articles, fliers, and other methods.
The public involvement plan includes methods that will elicit the best participation
from the community, including traditionally underrepresented groups.
Developing an effective public involvement plan is a strategic effort. WSDOT must
identify audiences, messages, strategies, and techniques that will meet the unique
needs of a proposed transportation project, as well as the needs of the public.
The ultimate goal of the public involvement plan is to allow members of the public
opportunities throughout the process to:
 Learn about the project.
 Provide information and options.
 Collaborate.
 Provide input intended to influence WSDOT decisions.

The plan will outline ways to identify and involve the communities affected by the
project; provide them with accessible information through reader-friendly documents,
graphics, plans, and summaries; and involve them in decision making.
An effective public involvement plan:
• Is tailored to the project.
• Encourages interactive communication.
• Demonstrates to residents that their input is valued and utilized.
• Includes all affected communities.
• Identifies and resolves issues early in the project development process.
• Ensures public access to relevant and comprehensible information.
• Informs the public of the purpose, need for, and benefits of the proposed action.
• Informs the public about the process that will be used to make decisions.
• Gains public support.
• Provides equal opportunity, regardless of disability, race, national origin, color,
gender, or income.
The region Communications and Environmental offices can provide expertise in
developing a public involvement plan tailored to a specific project. The HQ Access
and Hearings Section specializes in procedures for public hearings. Real Estate
Services personnel can provide expertise regarding acquisition, relocation assistance,
and other related programs. Enlisting the support of these groups is essential to the
success of WSDOT projects.
WSDOT recognizes local, state, federal, and tribal staff and elected officials as active
sponsors of proposed projects. Those officials might help develop and implement the
public involvement plan. Early and continued contact with these resources is key to
the success of a project.

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The public involvement plan might include:

• Objectives.
• Strategies.
• Tactics (or a list of proposed activities).
• Proposed time schedule to accomplish each project.
• Methods to track public comments.
• Methods used to consider comments during the decision-making process,
including follow-up procedures.
• Personnel, time, and funds needed to carry out the plan.
• Identification of the project partners and stakeholders.
Early use of demographics can help identify the public to be involved. After
identification, a variety of methods can be chosen to encourage the most effective
public involvement. This might include (directly or indirectly) any or all of the
following:
• Adjacent property owners and tenants
• Indian tribes
• Low-income groups
• Minority groups
• Cooperating and participating agencies
• Local, state, and federal government staff and elected officials
• Community groups such as clubs, civic groups, business groups, environmental
groups, labor unions, disability advocacy groups, and churches
• Commuters and the traveling public
• Emergency and utility service providers
• Adjacent billboard owners and clients
• The general public and others known to be affected
• Others expressing interest
The following are examples of common outreach methods:
• Public and open house meetings
• Drop-in information centers or booths
• Advisory committee meetings
• Design workshops
• Meetings with public officials
• Individual (one-on-one) meetings
• Meetings with community groups
• Project Internet pages
• WSDOT project e-mail alert lists
• Surveys
• Questionnaires
• Telephone hot lines
• Using established media relations and contacts
• Internet blogs
• Direct mail

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• Individual e-mails and letters

• Advisory committees and groups
• Public hearings
(a) Public Meetings and Open Houses
Public meetings range from large informational workshops to small groups using
one-on-one meetings with individuals. They are less formal than hearings. The
region evaluates the desired outcome from a meeting, decides how the input will
be tracked, and then plans accordingly.
• Open house meetings can be effective for introducing a project to the public
and stimulating an exchange of ideas.
• Small meetings are useful for gaining information from community groups,
underrepresented groups, neighborhood groups, and advisory committees.
• Workshop formats, where large groups are organized into small discussion
groups, serve to maximize the participation of all attendees while
discouraging domination by a few groups or individuals.
(b) Follow-Up Procedures
Effective public involvement is an ongoing collaborative exchange, and it is
necessary to provide follow-up information several times during a large project
to maintain a continuing exchange of information.
At significant stages, the region provides information about the project. Follow-
up information conveys, as accurately as possible, how public input was
considered during development of the project.
It may become necessary to revise the public involvement plan as the project
evolves, conditions change, oppositional groups emerge, or new issues arise.
Sometimes innovative methods must be used to ensure the inclusion of affected
community members. This is especially important for underrepresented groups,
such as minority and low-income groups, and in communities where a
significant percentage of the affected population does not speak English.
Consider the need for translators, interpreters, and providing written information
in languages other than English. Reference information on limited English
proficiency is provided in 210.04(2)(d). A resident advisory committee can
often help identify community issues and concerns as well as recommend
effective methods for public involvement.

(2) Public Involvement References

Following are a number of recommended publications, references, and training
courses available to assist regions in developing public involvement plans for
their projects.
(a) WSDOT Project Management Online Guide
A project’s public involvement plan is an essential element of the overall project
management plan. The WSDOT Project Management Online Guide is an Internet
resource intended to support delivery of transportation projects through effective
project management and task planning. The guide includes best practices, tools,
templates, and examples to enhance the internal and external communication
processes:  www.wsdot.wa.gov/projects/projectmgmt/onlineguide/preconstruction.htm

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(b) WSDOT Communications Intranet Page

The WSDOT Communications Intranet page provides guidance for effective
communications. This resource includes a Communications Manual, key
messaging, and WSDOT’s communications philosophy, and is an excellent
resource for developing a public involvement plan:
 http://wwwi.wsdot.wa.gov/communications/
(c) Context Sensitive Solutions and Community Involvement
A proposed transportation project must consider both its physical aspects as a
facility serving specific transportation objectives and its effects on the aesthetic,
social, economic, and environmental values within a larger community setting.
context sensitive solutions is a collaborative, interdisciplinary approach that
involves the community in the development of a project. WSDOT’s philosophy
encourages collaboration and consensus-building as highly advantageous to all
parties to help avoid delays and other costly obstacles to project implementation.
WSDOT endorses the context sensitive solutions approach for all projects, large
and small, from early planning through construction and eventual operation of
the facility. For further information, see WSDOT Executive Order E 1028
on context sensitive solutions:
 http://wwwi.wsdot.wa.gov/publications/policies/fulltext/1028.pdf
 http://www.wsdot.wa.gov/design/policy/csdesign.htm
 http://www.wsdot.wa.gov/design/policy/csdesignresources.htm
Additionally, the following HQ Design, Highways and Local Programs, and
Environment Internet pages offer an excellent array of publications, training,
and resources for public involvement:
 www.wsdot.wa.gov/environment/ej/
(d) Federal Highway Administration References
Improving the Effectiveness of Public Meetings and Hearings, FHWA
Guidebook, provides a variety of techniques and processes based on the practical
community involvement experience of its authors:
 www.ntl.bts.gov/docs/nhi.html
Public Involvement Techniques for Transportation Decision-Making, FHWA
September 1996, provides tools and techniques for effective public involvement:
 www.fhwa.dot.gov/reports/pittd/cover.htm
How to Engage Low-Literacy and Limited-English-Proficiency Populations in
Transportation Decisionmaking, FHWA 2006, provides tools and techniques for
identifying and including these populations:
 www.fhwa.dot.gov/hep/lowlim/index.htm
23 CFR 630, Subpart J, Final Rule on Work Zone Safety and Mobility, Work
Zone Public Information and Outreach Strategies. This Internet guide is designed
to help transportation agencies plan and implement effective public information
and outreach campaigns to mitigate the effects of road construction work zones:
 www.ops.fhwa.dot.gov/wz/info_and_outreach/index.htm

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(3) Legal Compliance Statements

All public announcements shall include the required statements relative to the
Americans with Disabilities Act of 1990 (ADA) and Title VI legislation. The region
Communications Office and the HQ Communications Office Intranet page can
provide the current version of both of these statements for legal compliance.
(a) ADA Compliance
The ADA and Section 504 of the Rehabilitation Act require WSDOT to inform
the general public of its obligation to ensure programs and activities are
accessible to and usable by persons with disabilities. For publications, the notice
must provide a way to obtain the materials in alternative formats (such as Braille
or taped). For public meetings and hearings, the notice must inform the public
that reasonable accommodations can be made for a variety of needs.
The public meeting/hearing facility must always meet minimum ADA
accessibility standards (such as ramps for wheelchair access, wide corridors,
and accessible rest rooms). Additionally, WSDOT must provide, upon request,
reasonable accommodations to afford equal access for persons with disabilities
to information, meetings, and so on. Reasonable accommodations can
include services and auxiliary aids such as qualified interpreters, transcription
services, assistive listening devices for persons who are deaf or hard of
hearing, or additional lighting for persons with visual impairments. The
WSDOT Office of Equal Opportunity can provide assistance for reasonable
accommodation provisions.
(b) Title VI of the Civil Rights Act
Title VI of the Civil Rights Act of 1964 requires that WSDOT inform the general
public of its obligation to ensure that no person shall, on the grounds of race,
color, national origin and/or sex, be excluded from participation in, be denied
the benefits of, or be otherwise discriminated against under any of its federally
funded programs and activities.

210.05 Public Hearings

By state and federal law, certain capital transportation projects propose actions that
require a public hearing. The remainder of this chapter provides guidance on public
hearing procedures.
The common types of public hearings associated with WSDOT projects include
environmental, design, corridor, and limited access hearings, which are discussed in
subsequent sections. The guidance in this chapter covers project actions that trigger a
hearing and the procedures for effectively planning, conducting, and completing the
hearing process.
The different types of public hearings follow similar steps for planning and
preparation of project materials and information. These steps facilitate efficient
reviews and approvals required for the hearing to proceed as planned. Special
attention to the scheduling of deliverables and notifications leading up to the hearing
help the process progress smoothly.

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Public hearing formats are either formal or informal. Limited access hearings are
always conducted as formal hearings. An informal process can be used for most other
hearings.
Hearings are often conducted in accordance with NEPA/SEPA procedures for
public involvement during the environmental documentation phase of the project.
The region reviews the requirements for hearings during the early stages of project
development and before completion of the draft environmental documents.

(1) Coordinating the Hearing

Preparing for and conducting a successful public hearing requires considerable
coordination and effort. The best way to do this is by establishing a support team
to identify and carry out the tasks and arrangements. It is crucial to identify and
schedule tasks and deliverables well in advance of a public hearing. A project team
might enlist the support of region specialists from Communications, Environmental,
Government Relations, Right of Way, Real Estate, and Traffic offices, as well as the
HQ Hearing Coordinator, HQ NEPA Policy staff, Office of Equal Opportunity, and
others involved with the project. The following exhibits and narrative help identify
whether a public hearing is required and how to prepare.

(2) Selecting the Hearing Type

By law, certain project actions or proposed conditions require that specific types of
public hearings are conducted. Exhibit 210-1 identifies project conditions and their
associated hearing requirements. If one or more of the conditions in Exhibit 210-1
occurs, a notice of opportunity for a hearing is required by federal and state law (USC
Title 23 §771.111 and RCW 47.52) and by WSDOT policy. Consult the Hearing
Coordinator in the HQ Access and Hearings Section, as well as project environmental
specialists, for hearing requirements.

(3) Selecting the Hearing Format

The types of public hearing formats used by WSDOT are known as formal and
informal. Hearing formats are different than hearing types. In some cases, the
hearing type will dictate the required format, such as with limited access hearings.
The following text and Exhibit 210-2 provide guidance on formats.
(a) Formal Hearings
A formal hearing is conducted by a moderator using a formal agenda, overseen
by a hearing examiner, and recorded by a court reporter, as required by law.
Limited access hearings and administrative appeal hearings require the use of
the formal hearing format. For projects that require a formal public hearing, it
is common for WSDOT to hold a public open house preceding the hearing.
The following are required for all formal hearings:
• Hearing notice with a fixed time and date (see 210.05(5) and (6))
• Fixed agenda and script
• Hearing examiner
• Hearing moderator (may be the hearing examiner)
• Court reporter

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• Specified comment period

• Hearing summary (see 210.05(10))
In addition to providing oral comments, people can write opinions on the
comment forms available at or after the hearing and submit them before the
announced deadline.
(b) Informal Hearings
An informal hearing is also known as an open format hearing. Individual oral
comments are recorded by a court reporter. The presence of a hearing examiner
and a formal agenda are optional.
These events are typically scheduled for substantial portions of an afternoon
or evening so people can drop by at their convenience and fully participate.
Activities usually include attending a presentation, viewing exhibits, talking to
project staff, and submitting written or oral comments.
The following items are features of an open format (or informal) hearing:
• They can be scheduled to accommodate people’s work schedules.
• Brief presentations about the project and hearing process are advertised at
preset times in the hearing notice. Presentations can be live, videotaped, or
computerized.
• Agency or technical staff is present to answer questions and provide details
of the project.
• Information is presented buffet-style, allowing participants access to specific
information.
• Graphics, maps, photos, models, videos, and related documents are
frequently used.
• People have the opportunity to clarify their comments by reviewing materials
and asking questions before commenting.
• People can comment formally before a court reporter, or they can write
opinions on comment forms and submit them before the announced deadline.

(4) Hearing Preparation

When region staff have determined that a formal or informal public hearing will
be held, they should contact the HQ Hearing Coordinator to discuss preliminary
details. The HQ Hearing Coordinator specializes in assisting with preparations for the
hearing and will usually attend. Other WSDOT groups involved with the project and
tasked with developing and implementing the public involvement plan can assist with
hearing preparations and provide assistance at the hearing.
The exhibits in this chapter can be used as checklists to identify important milestones
and work products needed. Important elements include setting an initial target date
for the hearing and agreeing on staff roles and responsibilities at the hearing.
(a) Setting the Hearing Date and Other Arrangements.
The Director & State Design Engineer, Development Division, sets the hearing
date at the recommendation of the HQ Hearing Coordinator. This is known as the
order of hearing. Final arrangements for the hearing date can be handled by
telephone or brief check-in meetings between the HQ Hearing Coordinator and
the region.

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The region proposes a hearing date based on the following considerations:

• Convenient for community participation. Contact local community and
government representatives to avoid possible conflict with local activities.
Consider times and locations that are most appropriate for the community.
• For corridor and design hearings, at least 30 days after circulation of the
draft environmental impact statement (DEIS) or the published notice of
availability of any other environmental document.
• In most cases, more than 45 days after submittal of the prehearing packet.
The region makes other arrangements as follows:
• Reviews the location of the hearing hall to ensure it is easily accessed
by public transportation (whenever possible), convenient for community
participation, and ADA accessible.
• Arranges for a court reporter.
• Requests that the HQ Hearing Coordinator provide a hearing examiner for all
limited access hearings and for other hearings, if desired.
• Develops a hearing agenda for all limited access hearings and for other types
of hearings, if desired.
• If requested in response to the hearing notice, provides communication
auxiliary aids and other reasonable accommodations required for persons
with disabilities. Examples include interpreters for persons who are deaf;
audio equipment for persons who are hard of hearing; language interpreters;
and the use of guide animals and Braille or taped information for persons
with visual impairments.
• All public hearings and meetings require the development of procedures for
the collection of statistical data (race, color, sex, and national origin) on state
highway program participants and beneficiaries such as relocatees, impacted
citizens, and affected communities. Public Involvement Forms should be
available for meeting attendees to complete. This form requests attendees to
provide information on their race, ethnicity, national origin, and gender. It
is available in English, Spanish, Korean, Russian, Vietnamese, Tagalog, and
Traditional and Simplified Chinese at:
 www.wsdot.wa.gov/equalopportunity/PoliciesRegs/titlevi.htm
• If demographics indicate that 5% or 1000 persons or more in the affected
project area speak a language other than English, vital documents,
advertisements, notices, newspapers, mailing notices, and other written and
verbal media and informational materials may need to be translated into other
languages to ensure social impacts to communities and people are recognized
and considered throughout the transportation planning and decision-making
process. In addition, language interpreters may need to be present during the
hearings or public meetings to ensure individuals and minority communities
are included throughout the process.

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(b) Developing the Prehearing Packet

The region prepares a prehearing packet, which contains an organized grouping
of project information to be used at the hearing. The project team members and
specialists enlisted to support the public involvement and hearing processes
typically coordinate to produce the prehearing packet elements. Much of the
information needed in the prehearing packet will come from the project’s public
involvement plan.
The following information is included in the prehearing packet:
1. Project Background Information and Exhibits
A project vicinity map and pertinent plans and exhibits for the hearing.
The prehearing packet also contains a brief written narrative of the project.
Usually, this narrative is already prepared and available in Project File
documents, public involvement plans, or on a project Internet page.
2. Proposed Hearing Type, Format, and Logistics
The prehearing packet identifies the type of hearing required. A hearing
support team provides various planning details and helps with arrangements
(date, time, place, and announcements). A public open house is often
scheduled on the same day, preceding a formal hearing, to provide
opportunity for community involvement.
3. News Release
The region Communications Office can assist in preparing announcements
for the hearing and other public events.
4. Legal Hearing Notice
Notices must contain certain legal statements provided by the HQ Access and
Hearings Section. (See 210.05(5) and (6) for guidance on notices.)
5. List of Newspapers and Other Media Sources
These are the media sources used to announce the hearing. The region
Communications Office has developed relations with reporters and media
outlets, including minority publications and media, and is accustomed to
working these issues. Enlist the office’s support for hearing preparations.
6. List of Legislators and Government Agencies Involved
Special notice is sent to local officials and legislators announcing public
hearings. At formal hearings, the moderator and agenda typically identify
those officials so they can interact with the public. The HQ Government
Relations Office can assist with identifying and notifying legislators and key
legislative staff within the project area.
7. The Hearing Agenda and Script
These are required for formal hearings and are prepared by the region.
The HQ Access and Hearings Section can provide sample agendas and
scripts to support the region in its hearing preparations.
Exhibit 210-3 provides a checklist of prehearing packet contents, including
additional items needed for limited access hearings.

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(c) Preparing and Sending a Prehearing Packet

You should prepare a prehearing packet at least 45 days in advance of the public
hearing and send it to the HQ Access and Hearings Section. The HQ Hearing
Coordinator reviews and concurs with the region’s plans and recommends the
Director & State Design Engineer, Development Division’s approval of the
hearing date. Headquarters concurrence with the prehearing packet typically
requires two weeks after receipt of the information.

(5) Public Hearing Notices: Purpose and Content

There are two types of public notices for hearings: notice of hearing and notice of
opportunity for a hearing. Consult the HQ Hearing Coordinator for specific project
hearing requirements and implementation strategies.
(a) Notice of Hearing
A notice of hearing is prepared and published when a hearing is required by law
and cannot be waived.
(b) Notice of Opportunity for a Hearing
In select cases, a notice of opportunity for a hearing is prepared and published
in order to gauge the public’s interest in having a particular hearing. This kind
of notice is only used if the requirements for a hearing can be legally waived.
In these cases, documentation is required as set forth in 210.05(7).
(c) Content Requirements
The HQ Access and Hearings Section provides sample notices to the region upon
request. Public notices include statements that are required by state and federal
statutes. Some important elements of a notice include the following:
• A map or graphic identifying project location and limits.
• For a notice of opportunity for a hearing, include the procedures for
requesting a hearing and the deadline, and note the existence of the relocation
assistance program for persons or businesses displaced by the project.
• For an environmental, corridor, design, or combined corridor-design hearing,
or for a notice of opportunity for a hearing, announce the availability of the
environmental document and accessible locations.
• Project impacts to wetlands; flood plains; prime and unique farmlands;
Section 4(f), 6(f), or 106 properties; endangered species or related habitats;
or affected communities.
• Information on any associated prehearing presentation(s).
• Americans with Disabilities Act and Title VI legislation statements.

(6) Publishing Hearing Notices: Procedure

To advertise a legal notice of hearing or a notice of opportunity for a hearing, use the
following procedure for appropriate media coverage and timing requirements:
(a) Headquarters Concurrence
As part of the prehearing packet, the region transmits the proposed notice and
a list of the newspapers in which the notice will appear to the HQ Hearing
Coordinator for concurrence prior to advertisement.

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(b) Region Distribution of Hearing Notice

Upon receiving Headquarters concurrence, the region distributes copies of the
hearing notice and news release as follows:
• Send a copy of the hearing notice and a summary project description to
appropriate legislators and local officials one week before the first publication
of a hearing notice. Provide the HQ Government Relations Office with a copy
of all materials that will be distributed to legislators, along with a
list of legislative recipients.
• Advertise the hearing notice in the appropriate newspapers within one week
following the mailing to legislators. The advertisement must be published in
a newspaper with general circulation in the vicinity of the proposed project or
with a substantial circulation in the area concerned, such as foreign language
and local newspapers. If affected limited-English-proficient populations
have been identified, other foreign language newspapers may be appropriate
as well. The legal notices section may be used or, preferably, a paid display
advertisement in a prominent section of the newspaper, such as the local
news section. With either type of advertisement, request that the newspaper
provide an affidavit of publication.
• Distribute the project news release to all appropriate news media about
three days before the first publication of a hearing notice, using newspapers
publishing the formal advertisement of the notice.
• Additional methods may also be used to better reach interested or affected
groups or individuals, including notifications distributed via project e-mail
lists, ads in local community news media, direct mail, fliers, posters, and
telephone calls.
• For corridor and design hearings, the first notice publication must occur at
least 30 days before the date of the hearing. The second publication must
be 5 to 12 days before the date of the hearing (see Exhibit 210-4). The first
notice for a corridor or design hearing shall not be advertised prior to public
availability of the draft environmental document.
• For limited access and environmental hearings, the notice must be published
at least 15 days prior to the hearing. The timing of additional publications is
optional (see Exhibit 210-5).
• For a notice of opportunity for a hearing, the notice must be published once
each week for two consecutive weeks. The deadline for requesting a hearing
must be at least 21 days after the first date of publication and at least 14 days
after the second date of publication.
• A copy of the published hearing notice is sent to the HQ Hearing Coordinator
at the time of publication.
(c) Headquarters Distribution of Hearing Notice
The HQ Hearing Coordinator sends a copy of the notice of hearing to the
Transportation Commission, Attorney General’s Office, HQ Communications
Office, and FHWA (if applicable).
For a summary of the procedure and timing requirements, see Exhibit 210-4
(for environmental, corridor, and design hearings) or Exhibit 210-5 (for limited
access hearings).

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(7) No Hearing Interest: Procedure and Documentation

As described in 210.05(5), in select cases the region can satisfy certain project
hearing requirements by advertising a notice of opportunity for a hearing. This
procedure can be beneficial, particularly with limited access hearings in cases where
very few abutting property owners are affected. If no hearing requests are received
after issuing the notice of opportunity, the following procedures and documentation
are required to waive a hearing.
(a) Corridor or Design Hearing
If no requests are received for a corridor or design hearing, the region transmits
a package, which includes the notice of opportunity for a hearing, the affidavit
of publication of the notice, and a letter stating that there were no requests for a
hearing, to the HQ Access and Hearings Section.
(b) Limited Access Hearing
When a notice of opportunity for a hearing is used to fulfill the requirements for a
limited access hearing and there are no requests for a hearing, the following steps
are taken:
• The region must secure signed hearing waivers from every abutting property
owner whose access rights will be affected by the project, as well as the
affected local agency. The HQ Access and Hearings Section can supply a
sample waiver to the region.
• The Project Engineer must contact every affected property owner of record
(not tenant) and the local agency to explain the proposed project. This
explanation must include information on access features, right of way
acquisition (if any), and the right to a hearing. Property owners must also be
advised that signing the waiver will not affect their right to fair compensation
for their property, nor will it affect their access rights or relocation benefits.
• The region transmits the original signed waivers to the HQ Access and
Hearings Section, along with the affidavit of publication of the notice of
opportunity for a limited access hearing and a recommendation for approval
of the right of way plan. Once the completed package is received by the HQ
Access and Hearings Section, it is submitted to the Director & State Design
Engineer, Development Division, for review and approval.
(c) Environmental Hearing
Environmental hearings cannot use the process of waivers to satisfy project
hearing requirements.

(8) Prehearing Briefs and Readiness

After publication of a hearing notice, the region should expect to receive public
requests for information and project briefings, including requests for information
in languages other than English.
(a) Presentation of Material for Inspection and Copying
The information outlined in the hearing notice and other engineering and
environmental studies, as well as information intended to be presented at the
hearing, must be made available for public review and copying throughout

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the period between the first advertisement and the approval of the hearing
summary or findings and order. The information may also need to be available
in languages other than English if indicated by demographics. The information
need not be in final form, but it must include every item currently included in the
hearing presentation. The environmental documents must also be available for
public review.
These materials are made available in the general locality of the project. The
region reviews the variables (the locations of the Project Office and project site;
the interested individuals; and the probability of requests for review) and selects
a mutually convenient site for the presentation of the information. In accordance
with RCW 42.56, a record should be kept for future evidence, stating who came
in, when, and what data they reviewed and copied.
(b) Hearing Briefing
On controversial projects, the HQ Hearing Coordinator arranges for a briefing
(held before the hearing) for those interested in the project. Attendants typically
include appropriate Headquarters, region, and FHWA personnel, with special
notice to the Secretary of Transportation. Region personnel present the briefing.
(c) Prehearing Presentation
The region is encouraged to give an informal presentation to the public for
discussion of the project prior to the hearing. A prehearing presentation is
informal, with ample opportunity for exchange of information between WSDOT
and the public. Providing community members with opportunities to talk about
their concerns in advance of the hearing promotes positive public relationships,
and can make the actual hearing proceed more smoothly. Prehearing
presentations can be open house meetings, drop-in centers, workshops, or other
formats identified in the public involvement plan.
The prehearing presentation is usually held about one week before the hearing for
more controversial projects, modified as needed.
Include the date, time, and place in the hearing notice and ensure it is mailed in
time to give adequate notice of the prehearing presentation.

(9) Conducting the Hearing

The hearing is facilitated by the Regional Administrator or a designee. Normally,
a hearing examiner is used when significant controversy or considerable
public involvement is anticipated. A hearing examiner is required for limited
access hearings.
A verbatim transcript of the proceedings is made by a court reporter.
Hearings are generally more informative and gain more public participation
when an informal format is used, where people’s views and opinions are openly
sought in a casual and personal way. The informal hearing format may be used
for all hearings except limited access hearings. At least one court reporter is
required to take individual testimony. Use displays, exhibits, maps, and tables,
and have knowledgeable staff available to answer specific questions about the
proposed project.

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It is the responsibility of the hearing moderator and other department representatives

to be responsive to all reasonable and appropriate questions. If a question or proposal
is presented at the limited access hearing that can only be answered at a later date, the
region shall reserve an exhibit to respond to the comment in the findings and order.
The hearing moderator must not allow any person to be harassed or subjected to
unreasonable cross-examination.
(a) Hearing Agenda Items
For all limited access hearings, and for other formal hearings, the region prepares
a hearing agenda to ensure all significant items are addressed. A hearing agenda
includes the following:
1. Opening Statement
• Highway and project name.
• Purpose of hearing.
• Description of how the hearing will be conducted.
• Introduction of elected officials.
• Federal/State/County/City relationship.
• Statutory requirements being fulfilled by the hearing.
• Status of the project with regard to NEPA/SEPA documents.
• Description of information available for review and copying.
• For environmental, corridor, or design hearings, notice that written
statements and other exhibits can be submitted during the open record
period following the hearing.
• Statement that all who want to receive written notification of WSDOT’s
action as a result of the hearing may add their names to the interest list or
file a notice of appearance for limited access hearings.
2. Project History
Present a brief project history, including purpose and need for the project,
public involvement program, future hearing opportunities, and hearings held.
3. Presentation of Plans
Develop alternatives that include comparable levels of detail, and present
them equally. Include the no-action alternative. Refer to any supporting
studies that are available to the public.
Identify a preliminary preferred alternative, if selected by WSDOT, for
more detailed development. When a preliminary preferred alternative has
been identified, stress that it is subject to revision and reevaluation based on
public comments, additional studies, and other information that may become
available.
4. Environmental, Social, and Economic Discussion
Discuss all positive and negative environmental, social, and economic
effects (or summarize the major effects), and refer to the environmental
documentation.

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5. Statements, Plans, or Counterproposals From the Public

Accept public views or statements regarding the proposal presented, the
alternatives, and the social, economic, and environmental effects identified.
Avoid evaluating the views presented while conducting the hearing.
6. Relocation Assistance Program
Explain the relocation assistance program and relocation assistance
payments available. At all hearings, the relocation assistance brochure must
be available for free distribution, including (if appropriate) brochures in
languages other than English. Real Estate Services personnel should be
available.
If the project does not require any relocations, the relocation assistance
discussion may be omitted. Make a simple statement to the effect that
relocation assistance is provided, but currently no relocations have been
identified for the project. The relocation brochure and personnel should still
be available to the public at the hearing.
7. Acquisition
Discuss right of way acquisition, estimated cost, and currently proposed
construction schedules and critical activities that may involve or affect
the public.
8. Closing
Summarize the hearing and announce proposed future actions.
9. Adjournment
Adjourn the hearing with sincere gratitude for the public’s valuable
participation.

(10) Hearing Summary and Adoption

Upon completion of a public hearing, a documentation and approval procedure leads
to official adoption of the hearing proceedings. After the hearing, a summary is
prepared by the region. There are two types of summary documents used, depending
on the type of hearing. For environmental, corridor, and design hearings, a hearing
summary is produced. Following a limited access hearing, a findings and order
document is prepared. Each of these packages is comprised of documentation
assembled by the region and approved by Headquarters.
(a) Hearing Summary Contents
The hearing summary includes the following elements:
1. Hearing transcript.
2. Copy of the affidavit of publication of the hearing notice.
3. Hearing material:
• Copies of the letters received before and after the hearing.
• Copies or photographs of, or references to, every exhibit used in
the hearing.

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4. Summary and analyses of all oral and written comments. Include

consideration of the positive and negative social, economic, and
environmental aspects of these comments.
(b) Limited Access Hearing Findings and Order
Following a limited access hearing, the “summary” document is labeled the
findings and order. Refer to 210.09(12) for the process description and required
documentation for findings and order documents.
(c) Adoption and Approval
For specific hearing types, see subsequent sections in this chapter related to
adoption procedures.
Exhibit 210-6 identifies the Headquarters approval authority for hearing summary
and findings and order documents.

210.06 Environmental Hearing

Early coordination with appropriate agencies and the public may help to determine
the appropriate level of environmental documentation, the scope of the document,
the level of analysis, and related environmental disciplines to be analyzed.
Environmental documents address the positive and negative social, economic, and
environmental project effects, as described in Chapter 225 and the Environmental
Manual. The project environmental documentation is the first step in the
environmental hearing procedure. Each step of the hearing procedure is dovetailed
into the environmental process and is important in achieving the appropriate
project documentation. Corridor and design hearings are not normally required for
Environmental Assessments, SEPA Checklists, and categorically excluded projects.
However, the opportunity for an environmental hearing might be required or
advisable for controversial proposals. When an environmental hearing is not required,
an informational meeting may serve as a useful forum for public involvement in the
environmental process. Consult with region environmental staff and the HQ Hearing
Coordinator for specific project requirements.
Projects requiring an Environmental Impact Statement (EIS) must use an evaluation
process called scoping in the NEPA and SEPA requirements. This process helps the
project proponents identify the significant issues and possible alternatives analyzed
and documented in the Draft EIS, and it must follow the public involvement plan
included in the environmental study plan for the project.
After the project has been thoroughly analyzed through the environmental evaluation
process and discussed within the community using informal public involvement
methods, a hearing is held to present and gather testimony. The hearing is timed
to fall within the comment period for the Draft EIS.
For an environmental hearing, the hearing notice must be published at least
15 days prior to the hearing. The timing of additional publications is optional
(see Exhibit 210-4).
Responses to comments on the Draft EIS must be addressed in the Final EIS.

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(1) Environmental Hearing Summary

The environmental hearing summary includes the items outlined in 210.05(10).

(2) Adoption of Environmental Hearing

Chapter 225 and the Environmental Manual provide guidance on NEPA and SEPA
procedures, documentation requirements, and approvals.

210.07 Corridor Hearing

A corridor hearing is a public hearing that:
• Is held before WSDOT is committed to a preferred alternative establishing
the final route corridor.
• Is held to ensure opportunity is afforded for effective participation by
interested persons in the process of determining the need for and location
of a state highway.
• Provides the public an opportunity to present views on the social, economic,
and environmental effects of the proposed alternative highway corridors.
A corridor hearing is required if any of the following project actions would occur:
• Proposed route on new location.
• Substantial social, economic, or environmental impacts.
• Significant change in layout or function of connecting roads or streets.
When a corridor hearing is held, the region must provide enough design detail
on the proposed alignment(s) within the corridor(s) that an informed presentation
can be made at the hearing. Justification to abandon an existing corridor must also
be presented.
For general procedures and notification requirements, see 210.05 and Exhibit 210-4.

(1) Corridor Hearing Summary

After the hearing, the region:
• Reviews the hearing transcript.
• Responds to all questions or proposals submitted at or subsequent to the hearing.
• Compiles a corridor hearing summary.
• Transmits three copies (four copies for Interstate projects) to the HQ Access and
Hearings Section.
When appropriate, the hearing summary may be included in the FEIS. If not
included, submit the complete corridor hearing summary to the HQ Access and
Hearings Section within approximately two months following the hearing.
The corridor hearing summary includes the items outlined in 210.05(10).

(2) Adoption of Corridor Hearing Summary

The HQ Access and Hearings Section prepares a package that contains the corridor
hearing summary and a formal description of the project and forwards it to the
Assistant Secretary, Engineering & Regional Operations, for adoption. The HQ
Hearing Coordinator notifies the region when adoption has occurred and returns
an approved copy to the region.

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210.08 Design Hearing

A design hearing is a public hearing that:
• Is held after a route corridor is established and approved, but before final design
of a highway is engineered.
• Is held to ensure an opportunity is afforded for the public to present its views
on each proposed design alternative, including the social, economic, and
environmental effects of those designs.
A design hearing is required if any of the following project actions will occur:
• Substantial social, economic, or environmental impacts.
• Significant change in layout or function of connecting roads or streets.
• Acquisition of a significant amount of right of way results in relocation of
individuals, groups, or institutions.
For general procedures and notification requirements, see 210.05 and Exhibit 210-4.

(1) Design Hearing Summary

The design hearing summary includes the elements outlined in 210.05(10).
Submit the complete hearing summary to the HQ Access and Hearings Section within
approximately two months following the hearing.
If new studies or additional data are required subsequent to the hearing, the region
compiles the information in coordination with the HQ Design Office.

(2) Adoption of Design Hearing Summary

After the hearing, the region reviews the hearing transcript, responds to all questions
or proposals submitted at or subsequent to the hearing, compiles a hearing summary,
and transmits three copies (four copies for Interstate projects) to the HQ Access and
Hearings Section. When appropriate, the design hearing summary may be included
in the final environmental document. The HQ Access and Hearings Section prepares
a formal document that identifies and describes the project and submits it to the
Director & State Design Engineer, Development Division, for approval. One
approved copy is returned to the region. The HQ Hearing Coordinator notifies the
region that adoption has occurred.
On Interstate projects, the Director & State Design Engineer, Development Division,
(or designee) submits the approved design hearing summary to the FHWA for federal
approval. If possible, this submittal is timed to coincide with the submittal of the
Design Decision Summary to the FHWA.

(3) Public Notification of Action Taken

The region prepares a formal response to individuals who had unresolved questions at
the hearing. The region keeps the public advised regarding the result(s) of the hearing
process, such as project adoption or revision to the plan. A project newsletter sent to
those on the interest list is an effective method of notification. Project news items can
be sent via e-mail or by more traditional methods.

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210.09 Limited Access Hearing

Limited access hearings are required by law (per RCW 47.52) whenever limited
access is established or revised on new or existing highways. Decisions concerning
limited access hearings are made on a project-by-project basis by the Director &
State Design Engineer, Development Division, based on information that includes the
recommendations submitted by the region (see Chapters 510, 520, 530, and 540).
Limited access hearing procedures generally follow those identified in 210.05;
however, several unique products and notifications are also prepared. These include
limited access hearing plans and notifications sent to abutting property owners and
local jurisdictions. (See 210.09(4) and Exhibit 210-3 for a listing of these products.)
Exhibit 210-5 presents a summary of the limited access hearing procedures.
Prior to the limited access hearing (RCW 47.52.131), discussions with the local
jurisdictions shall be held on the merits of the limited access report and the limited
access hearing plan(s). These are required exhibits for the limited access hearing.
(See Chapter 530 for guidance on limited access reports.)
The following information applies only to limited access hearings and procedures
for approval of the findings and order.

(1) Hearing Examiner

The HQ Access and Hearings Section hires an administrative law judge from the
Office of Administrative Hearings to conduct the limited access hearing.

(2) Order of Hearing

The order of hearing officially establishes the hearing date. The Director & State
Design Engineer, Development Division, approves the order of hearing. The HQ
Hearing Coordinator then notifies the region, the Attorney General’s Office, and the
hearing examiner of the official hearing date.

(3) Limited Access Hearing Plan

The region prepares a limited access hearing plan to be used as an exhibit at the
formal hearing and forwards it to the HQ Plans Engineer for review and approval
approximately 45 days before the hearing. This is a Phase 2 Plan (see Chapter 510).
The HQ Plans Engineer schedules the approval of the limited access hearing plan on
the Director & State Design Engineer, Development Division’s calendar.

(4) Limited Access Hearing Information to Abutters

The region prepares an information packet that must be mailed to abutters, and other
entities as specified below, at least 15 days prior to the hearing and concurrent with
advertisement of the hearing notice. These items are elements of the prehearing
packet as described in 210.05(4)(b) and in Exhibit 210-3. If some of the limited
access hearing packets are returned as undeliverable, the region must make every
effort to communicate with the property owners.
The limited access hearing packet for abutters contains the following:
• Limited access hearing plan
• Limited access hearing notice
• Notice of appearance

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The region also sends the limited access hearing packet to:
• The county and/or city.
• The owners of property listed on the county tax rolls as abutting the section
of highway, road, or street being considered at the hearing as a limited access
facility.
• Local agencies and public officials who have requested a notice of hearing or
who, by the nature of their functions, objectives, or responsibilities, are interested
in or affected by the proposal.
• Every agency, organization, official, or individual on the interest list.
The limited access hearing packet is also sent, when applicable, to:
• State resource, recreation, and planning agencies.
• Tribal governments.
• Appropriate representatives of the Department of the Interior and the Department
of Housing and Urban Development.
• Other federal agencies.
• Public advisory groups.

(5) Affidavit of Service by Mailing

The region prepares an affidavit of service by mailing. This affidavit states that the
limited access hearing packet was mailed at least 15 days prior to the hearing and that
it will be entered into the record at the hearing.

(6) Limited Access Hearing Plan Revisions

The limited access hearing plan cannot be revised after the Director & State Design
Engineer, Development Division (or designee), approves the plan without
rescheduling the hearing. If significant revisions to the plan become necessary during
the period between the approval and the hearing, the revisions can be made and must
be entered into the record as a revised (red and green) plan at the hearing.

(7) Limited Access Hearing Notice

The limited access hearing notice must be published at least 15 calendar days before
the hearing. This is a legal requirement and the hearing must be rescheduled if the
advertising deadline is not met. Publication and notice requirements are the same
as those required in 210.05, except that the statutory abutter mailing must be mailed
after notification to the appropriate legislators.

(8) Notice of Appearance

The HQ Hearing Coordinator transmits the notice of appearance form to the region.
Anyone wanting to receive a copy of the findings and order and the adopted right of
way and limited access plan must complete a notice of appearance form and return it
to WSDOT either at the hearing or by mail.

(9) Reproduction of Plans

The HQ Hearing Coordinator submits the hearing plans for reproduction at least
24 days prior to the hearing. The reproduced plans are sent to the region at least
17 days before the hearing, for mailing to the abutters at least 15 days before
the hearing.

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(10) Limited Access Hearing Exhibits

The region retains the limited access hearing exhibits until preparation of the draft
findings and order is complete. The region then submits all the original hearing
exhibits and three copies to the HQ Access and Hearings Section as part of the
findings and order package. Any exhibits submitted directly to Headquarters are sent
to the region for inclusion with the region’s submittal.

(11) Limited Access Hearing Transcript

The court reporter furnishes the original limited access hearing transcript to the
region. The region forwards the transcript to the hearing examiner, or presiding
authority, for signature certifying that the transcript is complete. The signed
original and three copies are returned to the region for inclusion in the findings and
order package.

(12) Findings and Order

The findings and order is a document containing the findings and conclusions of a
limited access hearing, based entirely on the evidence in the hearing record. The
region reviews a copy of the transcript from the court reporter and prepares a findings
and order package. The package is sent to the HQ Access and Hearings Section.
The findings and order package contains:
• The draft findings and order.
• Draft responses to comments (reserved exhibits).
• A draft findings and order Plan as modified from the hearing plan.
• All limited access hearing exhibits: originals and three copies.
• The limited access hearing transcript: original and three copies.
• The notice of appearance forms.
• Estimate of the number of copies of the final findings and order plan and text the
region will need for the mailing.

(13) Adoption of Findings and Order

The Assistant Secretary, Engineering & Regional Operations, adopts the findings and
order based on the evidence introduced at the hearing and any supplemental exhibits.
Following adoption of the findings and order, the HQ Plans Section makes the
necessary revisions to the limited access hearing plan, which then becomes the
findings and order plan.
The HQ Access and Hearings Section arranges for reproduction of the findings and
order plan and the findings and order text and transmits them to the region.
The region mails a copy of the findings and order plan and the findings and order text
to all parties that filed a notice of appearance and to all local governmental agencies
involved. Subsequent to this mailing, the region prepares an affidavit of service by
mailing and transmits it to the HQ Access and Hearings Section.
At the time of mailing, but before publication of the résumé, the region notifies
the appropriate legislators of WSDOT’s action.

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(14) Résumé
The résumé is an official notification of action taken by WSDOT following adoption
of a findings and order. The HQ Access and Hearings Section provides the résumé to
the region. The region must publish the résumé once each week for two consecutive
weeks, not to begin until at least ten days after the mailing of the findings and order.

(15) Final Establishment of Access Control

When the findings and order is adopted, the findings and order plan becomes a Phase
4 Plan (see Chapter 510). The establishment of access control becomes final 30 days
from the date the findings and order is mailed by the region, as documented by the
affidavit of service by mailing.

(16) Appeal Process

An appeal from the county or city must be in the form of a written disapproval,
submitted to the Secretary of Transportation, requesting a hearing before a board
of review.
An appeal from abutting property owners must be filed in the Superior Court of
the state of Washington, in the county where the limited access facility is to be
located, and shall affect only those specific ownerships. The plan is final for all
other ownerships.

210.10 Combined Hearings

A combined hearing often alleviates the need to schedule separate hearings to
discuss similar information. A combined hearing is desirable when the timing for
circulation of the draft environmental document is simultaneous with the timing for
corridor and design hearings and when all alternative designs are available for each
alternative corridor.
When deciding whether to combine hearings, consider:
• Whether there is controversy.
• Whether alternative corridors are proposed.
• The nature of the environmental concerns.
• The benefits to the public of a combined hearing.

210.11 Administrative Appeal Hearing

Administrative appeal hearings apply only to managed access highways, are
conducted as formal hearings, and are initiated by a property owner seeking to appeal
a decision made to restrict or remove an access connection. This is also known as an
adjudicative proceeding, and the procedure is presented in Chapter 540.

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210.12 Follow-Up Hearing

A new hearing or the opportunity for a hearing is required for any previously held
hearing when any one of the following occurs (USC 23, §771.111):
• Major actions (such as adoption of findings and order and approval of hearing
summaries) did not occur within three years following the date the last hearing
was held or the opportunity for a hearing was afforded.
• A substantial change occurs in the area affected by the proposal (due to
unanticipated development, for example).
• A substantial change occurs in a proposal for which an opportunity for a hearing
was previously advertised or a hearing was held.
• A significant social, economic, or environmental effect is identified that was not
considered at earlier hearings.

210.13 Documentation
For the list of documents required to be preserved in the Design Documentation
Package and the Project File, see the Design Documentation Checklist:
 www.wsdot.wa.gov/design/projectdev/

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Types of Hearings[1]

Limited Access
Environmental
Proposed Project Actions or Conditions

Combined

Follow-Up
Corridor
Design
Proposed route on new location X X

Substantial social, economic, or environmental impacts X X X X

Significant change in layout or function of connecting roads or streets X X X

Acquisition of significant amount of right of way results in relocation of

X X
individuals, groups, or institutions

Significant adverse impact on abutting real property X

An EIS is required or a hearing is requested for an EA X

Significant public interest or controversy X

Regulatory agencies have hearing requirements that could be

X
consolidated into one hearing process

Limited access control is established or revised X

If several hearings are required, consider efficiency of combining X

Major actions not taken within 3 years after date last hearing was held X[2]

An unusually long time has elapsed since the last hearing or the
X
opportunity for a hearing

Substantial change in proposal since prior hearing X

Significant social, economic, or environmental effect is identified and was

X
not considered at prior hearing

Notes:
[1] This table presents a list of project actions that correspond to required public hearings. The list is intended
as a guide and is not all-inclusive. In cases where several types of hearings are anticipated for a project,
a combined hearing may be an effective method. Consult with region and Headquarters environmental
staff, the designated Assistant State Design Engineer, and the HQ Access and Hearings Section to identify
specific hearing requirements and strategies.
[2] Posthearing major actions include: FHWA approvals (for Interstate projects); adoption of hearing summaries
and findings and order; and public notification of action taken, such as publishing a résumé.

Types of Public Hearings

Exhibit 210-1

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Hearing Format
Hearing Type
Formal Informal

Limited Access Required Not allowed

Environmental Either format acceptable

Design Either format acceptable

Corridor Either format acceptable

Combined Format depends on type*

Follow-Up Format depends on type*

Notes:
Check with the HQ Hearing Coordinator to identify specific hearing type and
appropriate hearing format.
* If a combined or follow-up hearing includes a limited access hearing, then
that portion of the hearing must adhere to the formal format.

Public Hearing Formats

Exhibit 210-2

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Additional Items for

All
Prehearing Packet Items Limited Access
Hearings
Hearings

Brief project description; purpose and public benefit; history; known

X
public perceptions; and support or opposition

Proposed hearing type X

Hearing arrangements: proposed date, time, and place X

Proposed hearing format: formal or informal [1]

X

Notice of whether an open house event will precede the hearing X

Vicinity map X

Plans for corridor and design alternatives with descriptions X

News release X

Legal notice of hearing X X[2]

List of newspapers and other media sources that will cover the news
X
release and hearing notice

List of legislators and government agencies involved X

Hearing agenda [3]

X[3]

Hearing script [3]

X[3]

Limited access report (see Chapter 530) X

Limited access hearing plan(s) (see Chapter 530) X

List of abutting property owners X

Notice of appearance form X

Notes:
The prehearing packet is prepared by the region and transmitted to the HQ Access and Hearings Section for
review, concurrence, and processing. This information is assembled in advance of the hearing to facilitate timely
announcements and a smooth-flowing event. The HQ Hearing Coordinator requires the prehearing packet 45 days
(or sooner) in advance of the proposed hearing date.
[1] Limited access hearings are required by law to be formal.
[2] For a limited access hearing, each abutting property owner affected by the project must receive the hearing
notice, along with the notice of appearance form and specific limited access hearing plan(s) showing their
parcel(s). Indicate in the prehearing packet the number of affected property owners to whom the packets will
be mailed.
[3] A hearing agenda and hearing script are required for a limited access hearing. Any formal hearing requires a
fixed agenda and a script. It is recognized that the script may be in draft format at the time of submittal of the
prehearing packet. The HQ Hearing Coordinator can assist in its completion and can provide sample scripts
and agendas.

Prehearing Packet Checklist

Exhibit 210-3

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Sequence for Corridor, Design, and Environmental Hearings

Preparatory Work
Consult with HQ Hearing Coordinator and environmental specialists to determine [see 210.05 &
specific requirements for a hearing or a notice of opportunity for a hearing. Exhibit 210-1]
Assemble support team; identify and schedule tasks and deliverables. [see 210.05(4)]
Prepare prehearing packet (news releases, legal notices, exhibits). [see 210.05(4)(b) &
Exhibit 210-3]
♦ Minimum 45 Days Prior to Hearing: Transmit Prehearing Packet to HQ [see 210.05(4)(b)]
HQ Hearing Coordinator reviews and concurs; schedules hearing.
Public Notifications and News Releases [see 210.05(5) & (6)]
♦ 35–40 Days Prior to Hearing (1 week prior to first public ad)
Send notice to legislators and local officials.
♦ 33–35 Days Prior to Hearing (about 3 days before advertisement)
Send letter with news release to media.
♦ 30 Days Prior to Hearing
Draft EIS becomes available and its open comment period begins.
Corridor and Design Hearings
♦ 30 Days Prior to Hearing: Publish First Notice*
Advertise at least 30 days in advance of hearing, but not prior to public availability of draft
environmental document.
♦ 5–12 Days Prior to Hearing: Publish Second Notice
Environmental Hearings
♦ 15 Days Prior to Hearing: Publish First Notice
Advertise at least 15 days in advance; timing of additional notices optional.
(If done in combination with design or corridor hearing, use 30-day advance notice.)
Prehearing Briefings [see 210.05(8)]
♦ 5–12 Days Prior to Hearing
Region confers with local jurisdictions; conducts hearing briefings and presentations;
and makes hearing materials and information available for public inspection and copying.
Conduct the Hearing [see 210.05(9)]
Conduct environmental, corridor, or design hearing.
Posthearing Actions
Court reporter provides hearing transcript to region (usually within 2 weeks).
♦ 2 Months After Hearing: Prepare Hearing Summary and Send to HQ [see 210.05(10)]
Region addresses public comments from hearing and throughout comment
period; prepares hearing summary and transmits to HQ Hearing Coordinator
for processing.
HQ Hearing Coordinator transmits hearing summary package to HQ approval [see Exhibit 210-6]
authority for approval.
HQ Hearing Coordinator notifies region of adoption and returns a copy of approved hearing summary
to region.
Notes:
Important timing requirements are marked ♦
* If the advertisement is a notice of opportunity for a hearing, requests must be received within 21 days after the
first advertisement. If there are no requests, see 210.05(7).

Sequence for Corridor, Design, and Environmental Hearings

Exhibit 210-4

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Sequence for Limited Access Hearing

Preparatory Work
Consult with HQ Access and Hearings Section. Determine requirements [see 210.05 &
for a limited access hearing or a notice of opportunity for a hearing. Exhibit 210-1]
Assemble support team; identify and schedule tasks and deliverables. [see 210.05(4)]
Prepare limited access report and limited access hearing plan(s). [see Chapters 510 & 530]
Prepare prehearing packet (legal notice, exhibits, information packets [see 210.05(4)(b) &
for abutting property owners). Exhibit 210-3]
♦ Minimum 45 Days Prior to Hearing: Transmit Prehearing Packet to HQ – [see
Transmit Limited Access Report and Hearing Plans for Approval 210.05(4)(b) &
HQ Hearing Coordinator reviews and concurs; schedules hearing; transmits 210.09]
limited access report and limited access hearing plan.
♦ 45 Days Prior to Hearing [see 210.09(2)&(3)]
HQ actions: Calendar order of hearing & limited access hearing plan
approved
♦ 24 Days Prior to Hearing: HQ Reproduction of Plans [see 210.09(9)]
HQ action: Approved limited access hearing plan(s) are reproduced in number
sufficient for mailing to abutters and other handout needs; one set to be used
as hearing exhibit.
Notifications, News Releases, Confer With Local Agencies
♦ 35–40 Days Prior to Hearing [see 210.05(6)]
Send notice to legislators and local officials (1 week prior to first public ad).
♦ 33–35 Days Prior to Hearing [see 210.05(6)]
Send letter with news release to media (about 3 days before advertisement).
♦ 15 Days Prior to Hearing: Publish First Notice* [see 210.05(6)]
Advertise at least 15 days in advance; timing of additional notices optional.
♦ 15 Days Prior to Hearing: Send Hearing Packets to Abutters [see 210.05(4)]
(Hearing notice, limited access hearing plan, notice of appearance form).
♦ 15 Days Prior to Hearing: Confer With Local Jurisdictions [see 210.05(8)]
Conduct the Hearing [see 210.05(6)]
Using agenda and script, conduct formal limited access hearing.
Posthearing Actions
Court reporter provides limited access hearing transcript to region. [see 210.09(11)]
Region prepares findings and order document and transmits to HQ [see 210.09(12)]
Hearing Coordinator.
Assistant Secretary, Engineering & Regional Operations, adopts findings and [see 210.09(13)]
order.
Limited access hearing plan becomes findings and order plan. [see 210.09(15)]
Findings and order reproduced and mailed to abutters and local jurisdictions. [see 210.09(13)]
HQ provides résumé to region and region publishes. [see 210.09(14)]
Notes:
Important timing requirements are marked ♦
* If the advertisement is a notice of opportunity for a hearing, requests must be received within 21 days after
the first advertisement. If there are no requests, see 210.05(7).

Sequence for Limited Access Hearing

Exhibit 210-5

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Hearing Summary Document WSDOT HQ Approval Authority

Limited access hearing findings and order Assistant Secretary, Engineering & Regional Operations

Corridor hearing summary Assistant Secretary, Engineering & Regional Operations

Environmental hearing summary Director, Environmental Services

Design hearing summary Director & State Design Engineer, Development Division

Hearing Summary Approvals

Exhibit 210-6

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July 2012
Public Involvement and Hearings Chapter 210

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Chapter 225 Environmental Coordination
225.01 General
225.02 Determining the Environmental Documentation
225.03 Identifying the Project Classification
225.04 Environmental Commitment File
225.05 Environmental Permits and Approvals
225.06 Documentation
225.07 References

225.01 General
The term “environmental documentation” refers to the documents produced for a project to
satisfy the requirements contained in the National Environmental Policy Act (NEPA) and the
State Environmental Policy Act (SEPA). The Environmental Manual and supporting web pages
provide detailed instructions on how to determine what level of documentation is required and
how to prepare the documents. This chapter provides a summary of the relevant provisions in
the Environmental Manual.

The purpose of the environmental document is to provide decision makers, agencies, and the
public with information on a project’s environmental impacts, alternatives to the proposed
action, and mitigation measures to reduce unavoidable impacts. Final environmental documents
identify and evaluate the project to be constructed. Because projects vary in their level of
environmental impacts, the rules on environmental documentation allow for different levels of
documentation. As a project’s impacts increase, so does the level of documentation.

The region Environmental Office and the NEPA/SEPA Compliance Section of the Headquarters
Environmental Services Office routinely provide environmental documentation assistance to
designers and project engineers.

225.02 Determining the Environmental Documentation

The Environmental Review Summary (ERS) provides the first indication of what form the
environmental documentation will take. The ERS is developed as part of the Project Summary,
which is prepared during the scoping phase of all projects in the construction program. The
Project Summary (see Chapter 300 for additional information) includes two components:
 Project Definition
 Environmental Review Summary

The ERS is part of the Project Summary database. The ERS describes the potential environ-
mental impacts, proposed mitigation, and necessary permits for a project. It establishes the
initial environmental classification and identifies the key environmental elements addressed in
the NEPA/SEPA process. The ERS database includes fully integrated “Help” screens. Contact your
region Environmental Office or Program Management Office to get set up to work in the
database.

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The typical process for classifying projects and determining the level of environmental
documentation is as follows:
 Once the project has been sufficiently developed to assess any environmental impacts,
the region completes the ERS based on the best information available at the scoping
phase of development.
 The region Environmental Manager then concurs with the classification by approving
the ERS, which enables the completed form to be included in the Project Summary
package.
 For NEPA, if a project has been determined to be a Categorical Exclusion (CE), the
Environmental Classification Summary/SEPA Checklist (ECS/SEPA Checklist) is
completed. The NEPA environmental review process is considered complete when the
region Environmental Manager approves the ECS package (guidance is provided in the
online Help in the ECS/SEPA Checklist database). If it is determined that a Categorical
Exclusion (CE), an Environmental Assessment (EA), or Environmental Impact Statement
(EIS) is required, the region evaluates the project schedule and arranges for
preparation of the appropriate document.
 For SEPA, the signing and submittal of the ECS/SEPA Checklist completes the
environmental classification process. On projects that are categorized as exempt from
SEPA, the environmental process is complete unless the project requires consultation
under the Endangered Species Act. On projects that do not meet the criteria for a SEPA
Categorical Exemption (WACs 197-11-800 and 468-12) and require a SEPA checklist
(WAC 197-11-960) or an EIS, those documents are prepared as necessary prior to
Project Development Approval.

At this early stage, the ERS allows environmental staff to consider potential impacts and
mitigations and required permits. For many projects, the WSDOT Geographic Information
System (GIS) Workbench coupled with a site visit provides sufficient information to fill out the
ERS (see the GIS Workbench online Help).

For most WSDOT projects, the Federal Highway Administration (FHWA) is the lead agency for
NEPA. Other federal lead agencies on WSDOT projects are the U.S. Army Corps of Engineers,
Federal Aviation Administration, Federal Railroad Administration, and Federal Transit
Administration.

225.03 Identifying the Project Classification

Based on the environmental considerations identified during preparation of the ERS, WSDOT
projects are classified for NEPA/SEPA purposes to determine the type of environmental
documentation required. Projects with a federal nexus (using federal funds, involving federal
lands, or requiring federal approvals or permits) are subject to NEPA and SEPA. Projects that are
state funded only, with no federal nexus, follow SEPA guidelines. Since many WSDOT projects
are prepared with the intent of obtaining federal funding, NEPA guidelines are usually followed.
(See Chapter 300 of the Environmental Manual for more information.)

225.04 Environmental Commitment File

As an initial part of project development, the region establishes a project commitment file.
Establishment of this file generally coincides with preparation of the environmental

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documentation. The file consists of proposed mitigation measures; commitments made to

regulatory agencies, tribes, and other stakeholders; and other documented commitments made
on the project. Further commitment types (right of way, maintenance, and so on) may be added
at the region’s discretion.

The region Environmental Office is responsible for creating and maintaining the commitment file
as a project progresses through its development process. Whenever commitments are made,
they are incorporated into project documents and added to the environmental commitment file
once they are finalized. Commitments are typically included within, but not limited to, the
following documents or approvals and any of their supplements or amendments:
 Memoranda, Agreements, Letters, Electronic Communications
 No-Effect Letters
 Biological Assessments
 Biological Opinions
 Concurrence Letters
 SEPA Checklists
 NEPA Categorical Exclusions
 NEPA Environmental Assessments
 NEPA/SEPA Environmental Impact Statements
 Finding of No Significant Impact (FONSI)
 Record of Decision (ROD)
 Section 106 Concurrence Letter from Tribes and Department of Archaeology & Historic
Preservation
 Mitigation Plans
 Environmental Permits and Applications, and Associated Drawings and Plans

Additional information (see Procedure 490-a) for establishing a commitment file is available
online at WSDOT’s Tracking Commitments webpage. WSDOT has a Commitment Tracking
System to organize and track commitments from the commitment file. Refer to the
Environmental Manual (Chapter 490) for policies associated with tracking commitments.

225.05 Environmental Permits and Approvals

WSDOT projects are subject to a variety of federal, state, and local environmental permits and
approvals. Performing field work in support of the project design may also require
environmental permits or approvals. Understanding and anticipating what permits and
approvals may be required for a particular project type will assist the designer in project
delivery. The Environmental Permits and Approval website provides guidance on the
applicability of permits and approvals. Because the facts of each project vary and the
environmental regulations are complex, reliance on either the Design Manual or the
Environmental Manual is insufficient. Consult region environmental staff.

The Environmental Review Summary, which is prepared as part of the Project Summary,
identifies some of the most common environmental permits that might be required based on
the information known at that stage. As the project design develops, additional permits and
approvals can be identified. Conducting project site visits for engineering and environmental

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Environmental Coordination Chapter 225

features may reduce project delays caused by late discoveries. Coordinate with and
communicate any project changes to region environmental staff.

The permit process begins well in advance of the actual permit application. For some permits,
WSDOT has already negotiated permit conditions through the use of programmatic and general
permits. These permits typically apply to repetitive, relatively simple projects, and the permit
conditions apply regardless of the actual facts of the project type. For complex projects, the
negotiations with permit agencies often begin during the environmental documentation phase
for compliance with the National Environmental Policy Act (NEPA) and the State Environmental
Policy Act (SEPA). The mitigation measures developed for the NEPA/SEPA documents are
captured as permit conditions on the subsequent permits.

Environmental permits require information prepared during the design phase to demonstrate
compliance with environmental rules, regulations, and policies. To avoid delays in project
delivery, it is necessary for the designer to understand and anticipate this exchange of
information. The timing of this exchange often affects design schedules, while the permit
requirements can affect the design itself. In complex cases, the negotiations over permit
conditions can result in iterative designs as issues are raised and resolved.

The Project Engineer is encouraged to meet with and discuss expectations with support groups
so that preliminary field investigations are conducted in compliance with environmental
permits, agreements, laws, or regulations. At a minimum, the support groups should know how
to access the environmental commitments for the project and determine which ones apply to
their work. If a non-compliance event occurs, coordinate with support groups so that they know
to initiate the Environmental Compliance Assurance Procedure (see 225.06(1) for details).

225.05(1) Environmental Compliance During Design Phase

The purpose of the Environmental Compliance Assurance Procedure (ECAP) is to recognize and
rectify environmental non-compliance events during all phases of the project development
process including the Design phase. The ECAP provides prompt notification to WSDOT
management and regulatory agencies. For purposes of ECAP, non-compliance events are
defined as actions that violate environmental permits, agreements, laws, or regulations.

Responsibilities for field work during design phase.

1. PE or designee:
Step A - Takes the necessary actions so that appropriate environmental documentation and
permits are obtained for field work during the PE phase
Step B - Provides permits and communicates permit conditions to support groups
performing field work (Geotechnical, Utilities, Environmental, etc.)

2. The Environmental Manager or designee will help generate or make accessible the
appropriate environmental documentation and permits.

3. Support Group / Field Crew is responsible for permit compliance, including the following:
 Confirming they have all the permits, and understanding of the permit conditions prior
to beginning work

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Chapter 225 Environmental Coordination

 Evaluating field operations, including access to specific locations, and developing work
plans so that permit conditions are met (Temporary Erosion and Sediment Control
(TESC), etc.)
 Recognizing and identifying non-compliance issues.
 Notifying the PE and Environmental Manager when non-compliance issues/events happen.
When non-compliance is suspected or known, it is the Project Engineer’s (PE) responsibility to
initiate the Notification and Resolution Process below. The Regional Environmental Manager will
serve as a resource to the PE and give priority to addressing the non-compliance event. The PE
and Environmental Manager shall work together on an appropriate response to avoid or
minimize environmental damage.

225.05(1)(a) Notification and Resolution Process

When non-compliance occurs or is suspected, the following steps are taken:

1. The person/support group who discovers an event shall immediately notify the PE.
2. The PE or designee shall:
Step A – Inform the field crew to suspend all work that is causing non-compliance.
Step B – Immediately contact the Environmental Manager or designee to help determine if
it is or is not a non-compliance event. (Note: if event is compliant; stop the notification
process and resume work activity).
Step C - If non-compliant, collaborate with the Environmental Manager to determine the
regulatory agencies with jurisdiction. Notify all regulatory agencies with jurisdiction.
Step D – Consult with the Environmental Manager regarding response actions taken so far
and any additional remediation actions that may be necessary.
Step E– Notify the appropriate Assistant Region Administrator or Engineering Manager for
Design and the Assistant State Design Engineer assigned to that Region or Project.
Step F – Additional notifications (see F.1 and F.2 below) from the PE are necessary when
the non-compliance event:
 Results in a formal written/verbal enforcement action from a regulatory agency or
 Presents significant risk to public health or
 Presents significant risk to the environment or
 Creates a public controversy. (The Region decides what “public controversy”
means.)
Step F.1 – Region Highway Projects: Notify the Region Administrator (give a courtesy
notification to the Assistant State Design Engineer assigned to the project).
Step F.2 – Mega Projects Highway Projects: Notify the Mega Project’s Program
Administrator (give a courtesy notification to the Assistant State Design Engineer
assigned to the project).
3. The Region Administrator, Assistant State Design Engineer, and/or Mega Projects
Program Administrator shall notify the appropriate agency executives as warranted by the
situation.

4. The Environmental Manager or designee shall:

Step A – Notify the Director of the Environmental Services Office (ESO) when the non-
compliance event:
 results in a formal written/verbal enforcement action from a regulatory agency;
 presents significant risk to public health or

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Environmental Coordination Chapter 225

 presents significant risk to the environment or

 creates a public controversy. (The Region decides what “public controversy” means)
Step B - Assist the PE in determining and recognizing the underlying root cause(s) that
resulted in the non-compliant event, and determining how to prevent a reoccurrence of
the event.
Step C - In consultation with the PE, identify and obtain new or modified permits,
approvals, or agreements as needed to rectify the non-compliance event.

5. The Director of the ESO shall notify the ESO Compliance Solutions Branch Manager.

225.05(1)(b) Documentation

1. The PE and the Environmental Manager shall coordinate and prepare the appropriate
responses to all regulatory agencies with jurisdiction. The responses shall include
documentation about the non-compliance event and how it was recognized and rectified.
2. The Environmental Manager, with assistance from the PE, shall record the details of the
non-compliance event in the WSDOT Commitment Tracking System (per RCW 47.85.040),
including but not limited to:
 Project Name and location, plus the name of the PE.
 Date of event.
 Location(s) on the project where the non-compliance event occurred.
 The type of work and the underlying root cause that resulted in the non-compliance
event.
 The environmental, permit, agreement, law, or regulation violated.
 Description of how the non-compliance event was recognized, rectified, and the
lessons learned.
 Which regulatory agencies and staff were notified, including dates of notification and
any tracking numbers provided.
 Whether or not regulatory agency staff conducted a site review in response to the
notification.

The ESO shall produce a yearly report of all written notifications or violations to the Washington
State Legislature (per RCW 47.85.040).

225.06 Documentation
Refer to Chapter 300 for design documentation requirements.

225.07 References

225.07(1) Federal/State Laws and Codes

42 United States Code (USC) 4321, National Environmental Policy Act of 1969 (NEPA)

23 Code of Federal Regulations (CFR) Part 771, Environmental Impact and Related Procedures

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Chapter 225 Environmental Coordination

23 CFR Part 774; 49 USC Section 303, Policy on Lands, Parks, Recreation Areas, Wildlife and
Waterfowl Refuges, and Historic Sites

36 CFR Part 800, Protection of Historic and Cultural Properties

40 CFR Parts 1500-1508, Council for Environmental Quality Regulations for Implementing NEPA

Chapter 43.21C Revised Code of Washington (RCW), State Environmental Policy Act (SEPA)

Chapter 47.85 Revised Code of Washington (RCW), Transportation Project Delivery and Review

Chapter 197-11 Washington Administrative Code (WAC), SEPA Rules

Chapter 468-12 WAC, WSDOT SEPA Rules

225.07(2) WSDOT Environmental Resources

WSDOT region environmental staff

Environmental Permits and Approval webpage:

 https://www.wsdot.wa.gov/environment/technical/permits-approvals

Environmental Manual, M 31-11, WSDOT

 www.wsdot.wa.gov/publications/manuals/m31-11.htm

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 Design Documentation,
Chapter 300 Approval, and Process Review
300.01 General
300.02 WSDOT Project Delivery
300.03 Design Documentation and Records Retention Policy
300.04 Project Design Approvals
300.05 FHWA Oversight and Approvals
300.06 Project Documents and Approvals
300.07 Process Review
300.08 References

300.01 General
This chapter provides the WSDOT design procedures, documentation and approvals necessary
to deliver successful projects on the transportation network in Washington, including projects
involving the Federal Highways Administration.

This chapter presents critical information for design teams, including:

 WSDOT’s Project Development process.
 Design documentation tools, procedures, and records retention policy.
 Major Project approvals including Design Approval, Project Development Approval,
Basis of Design, Design Analysis, and other specific project documents for design-bid-
build and for design-build delivery methods.
 FHWA oversight and approvals on Projects of Division Interest (PoDI).
 WSDOT and FHWA approvals for non-PoDI projects including Interstate new and
reconstruction and other specific documents as shown in the approvals exhibits.
 Information about conducting project process reviews.
 Additional references and resources.

For local agency and developer projects on state highways, design documentation is also
needed. It is retained by the region office responsible for the project oversight, in accordance
with the WSDOT records retention policy. All participants in the design process are to provide
the appropriate documentation for their decisions. See 300‐04(3) for information about the
approval process and authority. For more information about these types of projects, see the
Local Agency Guidelines and Development Services Manual available at the Publications Services
Index website:
 www.wsdot.wa.gov/Publications/Manuals/index.htm

For operational changes identified by the Traffic Office Low Cost Enhancement or Field
Assessment Program that are included in a project, design documentation is also needed. It is
retained by the region office responsible for the project oversight, in accordance with the
WSDOT records retention policy. This documentation will be developed by the region Traffic

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Design Documentation, Approval, and Process Review Chapter 300

Office in accordance with HQ Traffic Office direction and included in the design documentation
for the project.

For emergency projects, also refer to the Emergency Funding Manual. It provides the legal and
procedural guidelines for WSDOT employees to prepare all necessary documentation to respond
to, and recover from, emergencies and disasters that affect the operations of the department.

300.02 WSDOT Project Delivery

A project, and its delivery method, is developed in accordance with all applicable procedures,
Executive Orders, Directives, Instructional Letters, Supplements, and manuals; the Washington
State Highway System Plan; approved corridor sketches and planning studies; the
FHWA/WSDOT Stewardship and Oversight Agreement; scoping phase documentation, and the
Basis of Design.

Preservation projects with an overall project cost of $10 million and over—and all other projects
with an overall project cost of $2 million and over—are required to go through the Project
Delivery Method Selection process. The overall project cost is the total of the Preliminary
Engineering, Right of Way, and Construction Costs.

For all projects, the delivery method is determined using WSDOT Project Delivery Method
Selection Guidance (PDMSG), with the following exceptions:

 Projects under $2 million are programmatically exempt from PDMSG, do not require a
Project Delivery Method Selection Checklist, and will be Design Bid Build.
 Preservation Paving projects under $10 million are programmatically exempt from PDMSG,
do not require a Project Delivery Method Selection Checklist, and will be Design Bid Build.

Design Build’s most likely application would be for improvement projects in the mobility,
economic initiatives, or environmental subprograms where there are opportunities for
innovation, greater efficiencies, or significant savings in project delivery time.

The delivery method is determined using the WSDOT Project Delivery Method Selection
Guidance Memorandum found here:
 www.wsdot.wa.gov/Projects/delivery/designbuild/PDMSG.htm

The region develops and maintains documentation for each project using this chapter and the
Project File / Design Documentation Package checklists (see 300.03(3))

Refer to the Plans Preparation Manual for PS&E documentation. Exhibit 300-4 is an example
checklist of recommended items to be turned over to the construction office at the time of
project transition. An expanded version is available here:
 www.wsdot.wa.gov/design/projectdev/

300.02(1) Environmental Requirements

All projects involving a federal action require National Environmental Policy Act (NEPA)
documentation. WSDOT uses the Environmental Review Summary (ERS) portion of Project
Summary to scope environmental impacts associated with the proposed project and document
the anticipated environmental class of action (EIS/EA/CE). The environmental approval levels are
shown in Exhibit 300-2.

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Upon receipt of the ERS approval for projects requiring an EA or EIS under NEPA, the region
proceeds with environmental documentation, including public involvement, appropriate for the
magnitude and type of the project (see Chapter 210 and WSDOT Community Engagement Plan).

300.02(2) Real Estate Acquisition

Design Approval and approval of right of way plans are required prior to acquiring property. A
temporary construction easement may be acquired prior to Design Approval for State funded
projects and with completion of NEPA for Federally funded projects. For early acquisition of
right of way, consult the Real Estate Services Office, the April 2, 2013 memorandum on early
acquisition policy, and Right of Way Manual Chapter 6-3.

300.03 Design Documentation and Records Retention Policy

300.03(1) Purpose
Design documentation records the evaluations and decisions by the various disciplines that
result in design recommendations. Design assumptions and decisions made prior to and during
the scoping phase are included. Changes that occur throughout project development are
documented. Required justifications and approvals are also included.

300.03(2) Certification of Documents by Licensed Professionals

All original technical documents must bear the certification of the responsible licensee as listed
in Executive Order E 1010.

300.03(3) Project File and Design Documentation Package

The Project File and Design Documentation Package include documentation of project work,
including planning; scoping; community engagement; environmental action; the Basis of Design;
right of way acquisition; Plans, Specifications, and Estimates (PS&E) development; project
advertisement; and construction.

The Project File (PF) contains the documentation for planning, scoping, programming, design,
approvals, contract assembly, utility relocation, needed right of way, advertisement, award,
construction, and maintenance review comments for a project. A Project File is completed for all
projects and is retained by the region office responsible for the project. Responsibility for the
project may pass from one office to another during the life of a project, and the Project File
follows the project as it moves from office to office. With the exception of the DDP, the Project
File may be purged when retention of the construction records is no longer necessary.

See the Project File checklist for documents to be preserved in the Project File:
 www.wsdot.wa.gov/Design/Support.htm

The Design Documentation Package (DDP) is a part of the Project File and preserves the
decision documents generated during the design process. In each package, a summary (list) of
the documents included is recommended. The DDP documents and explains design decisions,
design criteria, and the design process that was followed. The DDP is retained in a permanent
retrievable file for a period of 75 years, in accordance with WSDOT records retention policy.

The Basis of Design, Design Parameters, Alternatives Comparison Table, and Design Analyses are
tools developed to document WSDOT practical design and decisions. Retain these in the DDP.

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Design Documentation, Approval, and Process Review Chapter 300

Refer to the remainder of this chapter and DDP checklist for documents to be preserved in the
DDP. See Design Documentation Package Checklist here:
 www.wsdot.wa.gov/Design/Support.htm

300.04 Project Design Approvals

This section describes WSDOT’s project design milestones known as Design Approval and Project
Development Approval. They are required approvals regardless of delivery method chosen by
WSDOT. Many of the documents listed under these milestones are described further in 300.06.
Information pertaining to FHWA approvals and oversight is provided in 300.05 which describes
Projects of Division Interest (PoDI) which are governed by a separate plan that specifies FHWA
and State responsibilities for the project. Documents for projects requiring FHWA review, Design
Approval, and Project Development Approval are submitted through the HQ Design Office.

300.04(1) Design Approval

When the Project Summary (see 300.06) documents are approved, and the region is confident
that the proposed design adequately addresses the purpose and need for the project, a Design
Approval should be pursued and granted at this early stage. Early approval is beneficial at this
point in the design phase and is most relevant to larger projects with longer PE phases Design
Approval establishes the policy for three years. This is a benefit for longer PE phases in that it
avoids design changes due to policy updates during that time and provides consistency when
purchasing right of way or producing environmental documentation.
The items below are included in the combined Design Approval/Project Development Approval
Package. Design Approval may occur prior to NEPA approval. Generally, Design Approval will not
be provided prior to an Access Revision Report being approved on an Interstate project.
Approval levels for design and PS&E documents are presented in Exhibits 300-1 through 300-3.
The following items are to be provided for Design Approval. See 300.06 for additional
information.
 Stamped cover sheet *
 A reader-friendly Design Approval memorandum that describes the project
 Project Vicinity Map
 Project Summary documents
 Basis of Design (BOD) *
 Alternatives Comparison Table
 Design Parameter Sheets
 Safety Analysis or Crash Analysis Report (CAR) *
 Current Project Design Analysis(s) *
 List of known Design Analysis documents (contact your ASDE)
 List of known Maximum Extent Feasible (MEF) documents (contact your ASDE)
 Channelization plans, intersection plans, or interchange plans (if applicable)
 Alignment plans and profiles (if project significantly modifies either the existing vertical
or horizontal alignment)
 Current cost estimate
* Include the original approved documents

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Design Approval is entered into the Design Documentation Package and remains valid for three
years or as approved by the HQ Design Office.
 If the project is over this three-year period and has not advanced to Project
Development Approval, evaluate policy changes or revised design criteria that are
adopted by the department during this time to determine whether these changes
would have a significant impact on the scope or schedule of the project.
 If it is determined that these changes will not be incorporated into the project,
document this decision with a memo from the region Project Development Engineer
that is included in the DDP.
 For an overview of design policy changes, consult the Detailed Chronology of Design
Manual revisions:  www.wsdot.wa.gov/design/policy/default.htm

300.04(1)(a) Design-Build Projects

Design Approval applies to design-build projects and is required prior to issuing a design-build
request for proposal (RFP).
Environmental documentation completion is recommended prior to issuing RFP, but is required
prior to contract execution.

300.04(2) Project Development Approval

When all project development documents are completed and approved, Project Development
Approval is granted by the approval authority designated in Exhibit 300-1. The Project
Development Approval becomes part of the DDP.
Refer to this chapter and the DDP checklist for design documents that may lead to Project
Development Approval. Exhibits 300-1 through 300-3 provide approval levels for project design
and PS&E documents.
The following items must be approved prior to Project Development Approval:
 Stamped cover sheet
 A reader friendly Project Development Approval (PDA) Memorandum that describes
the project
 Project Vicinity Map
 Design Approval documents (and any supplements)
Updated Basis of Design (BOD) *
Updated list of Project Design analysis(s) *
Updated cost estimate
 NEPA Approvals
 SEPA Approvals
* Include the original approved documents
Project Development Approval remains valid for three years.
 Evaluate policy changes or revised design criteria that are adopted by the department
during this time to determine whether these changes would have a significant impact
on the scope or schedule of the project.
 If it is determined that these changes will not be incorporated into the project,
document this decision with a memo from the region Project Development Engineer
that is included in the DDP.

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 For an overview of design policy changes, consult the Detailed Chronology of Design
Manual revisions:  www.wsdot.wa.gov/design/policy/default.htm

300.04(2)(a) Design-Build Projects

For design-build projects, the design-builder shall refer to the project Request for Proposal (RFP)
for specification on final and intermediate deliverables and final records for the project. Project
Development Approval is required prior to project completion.

It is a prudent practice to start the compilation of design documentation early in a project and to
acquire Project Development Approval before the completion of the project. At the start of a
project, it is critical that WSDOT project administration staff recognize the importance of all
required documentation and how it will be used in the design-build project delivery process.

300.04(3) Local Agency and Developer Services Approvals

Local agencies or developers proposing projects for construction on state highways, or within
WSDOT jurisdiction on city streets that serve as part of state highways per RCW 47.24, are
required to document design decisions using the WSDOT design documentation policy (see
300.03) and as follows. The local agency or developer is required to document all decisions that
change one or more design elements (see 1105.02) using the Basis of Design. Documentation is
submitted to WSDOT for review and approval according to Exhibit 300-5. Where FHWA approval
is indicated, WSDOT will forward submitted information to FHWA for their approval and
transmit FHWA’s approval, comments, and/or questions back to the submitter.

In cases where design decisions are imposed on the local agency or developer by WSDOT or
FHWA, in order to secure their approval, those specific decisions are to be documented by
WSDOT. Note that the requirement to submit a Basis of Design for approval may be waived by
the approving authority designated in Exhibit 300-5, based on the criterion in 1100.10(1)(a).
When a Region is the approval authority for the BOD and is considering an exemption, the
Region approving authority can assume the role of the Assistant State Design Engineer to
determine if an exemption is appropriate. For more information about the Basis of Design, see
Chapters 1100 through 1106.

300.05 FHWA Oversight and Approvals

The March 2015 Stewardship & Oversight (S&O) Agreement between WSDOT and FHWA
Washington Division created new procedures and terminology associated with FHWA oversight
and approvals. One such term, and new relevant procedure, is “Projects of Division Interest”
(PoDI) described below.

For all projects, on the National Highway System (NHS), the level of FHWA oversight and
approvals can vary for numerous reasons such as type of project, the agency doing the work,
PoDI/non-PoDI designation, and funding sources. Oversight and funding do not affect the level
of design documentation required for a project.

Documents for projects requiring FHWA review, Design Approval, and Project Development
Approval are submitted through the HQ Design Office.

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300.05(1) FHWA Projects of Division Interest (PoDI)

Projects of Division Interest (PoDI) are a primary set of projects for which FHWA determines the
need to exercise oversight and approval authority. These are projects that have an elevated risk,
contain elements of higher risk, or present a meaningful opportunity for FHWA involvement to
enhance meeting program or project objectives. Collaborative identification of these projects
allows FHWA Washington Division to concentrate resources on project stages or areas of
interest. It also allows WSDOT to identify which projects are PoDIs and plan for the expected
level of engagement with FHWA.

The Stewardship & Oversight Agreement generally defines Projects of Division Interest as:
 Major Projects (A federal aid project with total cost >$500M)
 TIGER Discretionary Grant Projects
 NHS Projects that may require FHWA Project or Program Approvals
 Projects Selected by FHWA based on Risk or Opportunity

The S&O Agreement also states: Regardless of retained project approval actions, any Federal-
aid Highway Project either on or off the NHS that the Division identifies as having an elevated
level of risk can be selected for risk-based stewardship and oversight and would then be
identified as a PoDI.

For each project designated as a PoDI, FHWA and WSDOT prepare a Project-Specific PoDI
Stewardship & Oversight Agreement which identifies project approvals and related
responsibilities specific to the project.

300.05(2) FHWA Approvals on Non-PoDI Projects

On projects that are not identified as PoDI, FHWA approvals are still required for various items
as shown in Exhibit 300-1. For example, FHWA approval is still required for any new or revised
access point (including interchanges, temporary access breaks, and locked gate access points) on
the Interstate System, regardless of funding source or PoDI designation (see Chapter 550).

The Exhibit 300-1 approval table refers to New/Reconstruction projects on the Interstate.
New/Reconstruction projects include the following types of work:
 Capacity changes: add a through lane, convert a general-purpose (GP) lane to a special-
purpose lane (such as an HOV or HOT lane), or convert a high-occupancy vehicle (HOV)
lane to GP.
 Other lane changes: add or eliminate a collector-distributor or auxiliary lane. (A rural
truck climbing lane that, for its entire length, meets the warrants in Chapter 1270 is not
considered new/reconstruction.)
 New interchange.
 Changes in interchange type such as diamond to directional or adding a ramp.
 New or replacement bridge (on or over, main line, or interchange ramp).
 New Safety Rest Areas Interstate.

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Design Documentation, Approval, and Process Review Chapter 300

Documents for projects requiring FHWA review, Design Approval, and Project Development
Approval are submitted through the HQ Design Office.

300.06 Project Documents and Approvals

This section lists several major design documents generated for a project and they all are
retained in the Design Documentation Package. The Basis of Design, Alternatives Comparison
Table, Design Parameters, and Design Analyses are tools used to document practical design
decisions.

See the Project File and Design Documentation Package checklists described in 300.03(3) for
complete list of documents.

For approval levels see Exhibits 300-1 through 300-3 or a project-specific S&O Agreement for
PoDI projects.

300.06(1) Project Summary

The Project Summary provides information on the results of the scoping phase; links the project
to the Washington State Highway System Plan and the Capital Improvement and Preservation
Program (CIPP); and documents the design decisions, the environmental classification, and
agency coordination. The Project Summary is developed and approved before the project is
funded for design and construction, and it consists of the ERS, and PD documents. The Project
Summary database contains specific online instructions for completing the documents.
300.06(1)(a) Project Definition (PD)

The PD identifies the various disciplines and design elements that are anticipated to be
encountered in project development. It also states the purpose and need for the project, the
program categories, and the recommendations for project phasing. The PD is initiated early in
the scoping phase to provide a basis for full development of the ERS, schedule, estimate, Basis
of Estimate, and Basis of Design (where indicated in scoping instructions). If circumstances
necessitate a change to an approved PD, the project manager and the regional program
manager will document the change according to the CPDM Change Management process. For
more information, see the Program Management Manual, Chapter 9 Managing Change.

300.06(1)(b) Environmental Review Summary (ERS)

The ERS lists the potentially required environmental permits and approvals, environmental
classifications, and environmental considerations. The ERS is prepared during the scoping phase
and is approved by the region. If there is a change in the PD, the information in the ERS must be
reviewed and revised to match the rest of the Project Summary. For actions classified as a CE
under NEPA, the approved ERS becomes the ECS when the project is funded and moves to
design. The region may revise the ECS as appropriate (usually during final design) as the project
advances. The ECS serves as the NEPA environmental documentation for CE projects. The region
Environmental Manager approves the ECS and may send it to FHWA for their approval. The
ERS/ECS database includes fully integrated help screens that provide detailed guidance. Contact
your region Environmental Office for access.

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300.06(2) Basis of Design (BOD)

The BOD captures important decisions that control the outcome of a project, including identified
performance needs, context, design controls and design elements necessary to design the
practical alternative. When applicable attach supporting documents, such as the Alternatives
Comparison Table and Design Parameters to the BOD. (See Chapter 1100 for further discussion
on these documents). The Basis of Design (BOD) is part of the DDP.

300.06(3) Basis of Estimate (BOE)

The BOE contains the assumptions, risks, and information used to develop an estimate. The BOE
is reviewed and updated during each phase of a project. The confidence of the estimate, either
overall or for particular items, is also identified within the BOE. Generally, the BOE is started
during the scoping phase because it is required for Project Summary approval; however, in more
complex situations the BOE may have begun during the planning phase. For more information,
see the Cost Estimating Manual for WSDOT Projects.

300.06(4) Design Analysis

A Design Analysis is a process and tool used to document important design decisions,
summarizing information needed for an approving authority to understand and support the
decision.

A Design Analysis is required where a dimension chosen for a design element that will be
changed by the project is outside the range of values provided for that element in the Design
Manual. A Design Analysis is also required where the need for one is specifically referenced in
the Design Manual.

A region approved Design Analysis is required if a dimension or design element meets current
AASHTO guidance adopted by the Federal Highway Administration (FHWA), such as A Policy on
Geometric Design of Highways and Streets, but is outside the corresponding Design Manual
criteria. See Exhibit 300-1 for Design Analysis approval authorities.

In the case of a shoulder width reduction at an existing bridge pier or abutment, sign structure
or luminaire base in a run of median barrier, the Design Parameter Sheet may be used instead of
a Design Analysis to document the dimensioning decision for the shoulder at that location.

A template is available to guide the development of the Design Analysis document here:
 www.wsdot.wa.gov/design/support.htm.

Email a PDF copy of all Region approved Design Analyses to the ASDE supporting your region.

300.07 Process Review

The Assistant State Design Engineers work with the regions on project development and
conduct process reviews on projects. The process review is done to provide reasonable
assurance that projects are prepared in compliance with established policies and procedures
and that adequate records exist to show compliance with state and federal requirements.
Process reviews are conducted by WSDOT, FHWA, or a combination of both.

The design and PS&E process review is performed at least once each year by the HQ Design
Office. The documents used in the review process are the Design Documentation Package

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Design Documentation, Approval, and Process Review Chapter 300

Checklist(s), Basis of Design, Basis of Estimate, the PS&E Review Checklist, and the PS&E Review
Summary. These are generic forms used for all project reviews. Copies of these working
documents are available for reference when assembling project documentation. The HQ Design
Office maintains current copies at:  www.wsdot.wa.gov/design/support.htm.

Each project selected for review is examined completely and systematically beginning with the
scoping phase (including planning documents) and continuing through contract plans and, when
available, construction records and change orders. Projects are normally selected after contract
award. For projects having major traffic design elements, the HQ Traffic Operations Office is
involved in the review. The WSDOT process reviews may be held in conjunction with FHWA
process reviews.

The HQ Design Office schedules the process review and coordinates it with the region and
FHWA.

300.07(1) Process Review Agenda

When conducting joint process review with FHWA, the Process Review Report will outline
specific agenda items.

A WSDOT process review follows this general agenda:

1. Review team meets with region personnel to discuss the objective of the review.
2. Review team reviews the design and PS&E documents, construction documents, and change
orders (if available) using the checklists.
3. Review team meets with region personnel to ask questions and clarify issues of concern.
4. Review team meets with region personnel to discuss findings.
5. Review team submits a draft report to the region for comments and input.
6. If the review of a project shows a serious discrepancy, the region design authority is asked
to report the steps that will be taken to correct the deficiency.
7. Process review summary forms are completed.
8. Summary forms and checklists are evaluated by the Director & State Design Engineer,
Development Division.
9. Findings and recommendations of the Director & State Design Engineer, Development
Division, are forwarded to the region design authority for action and/or information within
30 days of the review.

300.08 References

300.08(1) Federal/State Laws and Codes

23 Code of Federal Regulations (CFR) 635.111, Tied bids

23 CFR 635.411, Material or product selection

Revised Code of Washington (RCW) 47.28.030, Contracts – State forces – Monetary limits –
Small businesses, minority, and women contractors – Rules

RCW 47.28.035, Cost of project, defined

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Chapter 300 Design Documentation, Approval, and Process Review

“Washington Federal-Aid Stewardship Agreement,”

 www.wsdot.wa.gov/publications/fulltext/design/ASDE/2015_Stewardship.pdf

300.08(2) Design Guidance

WSDOT Directional Documents Index, including the one listed below:
 http://wwwi.wsdot.wa.gov/publications/policies
Executive Order E 1010, “Certification of Documents by Licensed Professionals,” WSDOT

WSDOT technical manuals, including those listed below:

 www.wsdot.wa.gov/publications/manuals/index.htm
 Advertisement and Award Manual, M 27-02, WSDOT
 Cost Estimating Manual for WSDOT Projects, M 3034, WSDOT
 Design Manual, M 22-01, WSDOT
 Emergency Relief Procedures Manual, M 3014, WSDOT
 Environmental Manual, M 31-11, WSDOT
 Hydraulics Manual, M 23-03, WSDOT
 Highway Runoff Manual, M 31-16, WSDOT
 Plans Preparation Manual, M 22-31, WSDOT
 Roadside Manual, M 25-30, WSDOT
 Roadside Policy Manual, M 3110, WSDOT
 Temporary Erosion and Sediment Control Manual, M 3109, WSDOT

Limited Access and Managed Access Master Plan, WSDOT

 www.wsdot.wa.gov/design/accessandhearings/

Program Management Manual, M 3005, WSDOT

http://wwwi.wsdot.wa.gov/publications/manuals/fulltext/M3005/PMM.pdf

Washington State Highway System Plan, WSDOT

 www.wsdot.wa.gov/planning/

300.08(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, 2011

Mitigation Strategies for Design Exceptions, FHWA, July 2007. This publication provides detailed
information on design exceptions and mitigating the potential adverse impacts to highway
safety and traffic operations.

Highway Capacity Manual (HCM), latest edition, Transportation Research Board, National
Research Council

Highway Safety Manual (HSM), AASHTO

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Design Documentation, Approval, and Process Review Chapter 300

Exhibit 300-1 Approval Authorities

Design
Basis of Design Design Analysis Approval and
Project Type (BOD) Approval Project
Approval [1] [2] [11] Development
Approval
Project of Division Interest (PoDI) [10] [10] [10]

Interstate

New/Reconstruction Regardless of funding source [3] FHWA FHWA FHWA [4]

Intelligent Transportation Systems (ITS) Improvement

Project over $1 million HQ Design HQ Design HQ Design
Preservation project HQ Design HQ Design Region
All Other Regardless of funding source [12] HQ Design HQ Design Region

National Highway System (NHS)

Projects on all limited access highways, or on managed

HQ Design HQ Design [5] Region
access highways outside of incorporated cities and towns
Projects on managed access highways within incorporated
cities and towns
Inside curb or EPS [6][7] HQ Design HQ Design Region
Outside curb or EPS City/Town HQ LP City/Town
Non-National Highway System (Non-NHS)
Improvement projects on all limited access highways, or
on managed access highways outside of incorporated HQ Design HQ Design Region
cities and towns

Improvement projects on managed access highways

within incorporated cities and towns [9]
Inside curb or EPS [6][7] HQ Design HQ Design Region
Outside curb or EPS City/Town HQ LP City/Town
Preservation projects on limited access highway, or on
managed access highways outside of incorporated cities Region Region Region
and towns, or within unincorporated cities and towns [8]
Preservation projects on managed access highways within
incorporated cities and towns [8]
Inside curb or EPS [6][7] Region Region Region
Outside curb or EPS City/Town HQ LP City/Town

FHWA = Federal Highway Administration

HQ = WSDOT Headquarters
HQ LP = WSDOT Headquarters Local Programs Office
EPS = Edge of paved shoulder where curbs do not exist
NHS = National Highway System
 www.wsdot.wa.gov/mapsdata/travel/hpms/NHSRoutes.htm

For table notes, see the following page.

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Chapter 300 Design Documentation, Approval, and Process Review

Exhibit 300-1 Approval Authorities (continued)

Notes:
[1] These approval levels also apply to Design Analysis processing for local agency and
developer work on a state highway.
[2] See 300.06(4).
[3] For definition of New/Reconstruction, see 300.05(2).
[4] FHWA will provide Design Approval prior to NEPA Approval, but will not provide Project
Development Approval until NEPA is complete.
 http://www.wsdot.wa.gov/publications/fulltext/design/ASDE/2015_Stewardship.pdf

[5] For guidance on the need for Design Analyses related to access management, see Chapters
530 and 540.
[6] Includes raised medians (see Chapter 1600).
[7] Curb ramps are still included (see Chapter 1510).
[8] For Bridge Replacement projects in the Preservation program, follow the approval level
specified for Improvement projects.
[9] Refer to RCW 47.24.020 for more specific information about jurisdiction and
responsibilities that can affect approvals.
[10] Projects of Division Interest (PoDI) must receive FHWA approvals per the PoDI Agreement
regardless of funding source or project type.
[11] A region approved Design Analysis is required if a dimension or design element meets
current AASHTO guidance adopted by the Federal Highway Administration (FHWA), such as
A Policy on Geometric Design of Highways and Streets, but is outside the range of
corresponding Design Manual criteria. Email a PDF copy of all Region approved Design
Analyses to the ASDE supporting your region.
[12] Reduction of through lane or shoulder widths (regardless of project type) requires FHWA
review and approval, except shoulder reductions for existing bridge pier or abutment, sign
structure or luminaire base in a run of median barrier as allowed by 300.06(4).

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Design Documentation, Approval, and Process Review Chapter 300

Exhibit 300-2 Approvals

Approval Authority
Item
Region HQ FHWA
Program Development
Work Order Authorization X X [1]
Public Hearings
Corridor Hearing Summary X [2]
Design Hearing Summary X [3] X [8]
Limited Access Hearing Plan X [4]
Limited Access Findings and Order X [5]
Environmental Document
Class l NEPA (EIS) [7] X
SEPA (EIS) X
Class II NEPA – Categorical Exclusion (CE) Documented in ECS form X
SEPA – Categorical Exemption (CE) X
Class lll NEPA – Environmental Assessment (EA) [7] X
SEPA Environmental Checklist & Determination of Non-Significance
X
(DNS)
Design
Basis of Design (BOD) [9] [9] [9]
Intersection Control Type X [20] X [22]
Experimental Features X X
Environmental Review Summary X
Final Project Definition X [10]
Interstate Access Revision Report [7] X
Any Break in Interstate Limited Access [7] X
Non-Interstate Access Revision Report X
Break in Partial or Modified Limited Access X
Intersection or Channelization Plans X
Right of Way Plans [11] X
Monumentation Map X
Materials Source Report X [12]
Pavement Determination Report X [12]
Roundabout Geometric Design (see Chapter 1320 for guidance) X
Resurfacing Report X [12]
Signal Permits X [13]
Geotechnical Report X [12]
Tied Bids X [14]

Table continued on the following page, which also contains the notes.

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Chapter 300 Design Documentation, Approval, and Process Review

Exhibit 300-2 Approvals (continued)

Approval Authority
Item
Region HQ FHWA
Bridge Design Plans (Bridge Layout) X X
Preliminary Bridge Plans for Unusual/Complex Bridges on the Interstate [7] X
Structures Requiring TS&Ls X
Hydraulic Report X [15] [15]
Preliminary Signalization Plans X [6][18]
Signalization Plans X [20]
Illumination Plans X [20]
Intelligent Transportation System (ITS) Plans X [20]
ITS Systems Engineering Analysis Worksheet (Exhibit 1050-2) X [20]
Rest Area Plans X
Roadside Restoration Plans X [16] X [17]
Planting Plans X [16] X [17]
Grading Plans X
Continuous Illumination – Main Line X [18]
Tunnel Illumination X [18]
High Mast Illumination X [18]
Work Zone Transportation Management Plan/Traffic Control Plan X [20]
Public Art Plan – Interstate (see Chapter 950) X [16] X [17][21] X
Public Art Plan – Non-Interstate (see Chapter 950) X [16] X [17][21]
Crash Analysis Report X [20] X
ADA Maximum Extent Feasible Document (see Chapter 1510) X X
Notes: [10] Approved by HQ Capital Program Development
[1] Federal-aid projects only. and Management (CPDM).
[2] Approved by Assistant Secretary, Engineering & [11] Certified by the responsible professional
Regional Operations. licensee.
[3] Approved by Director & State Design Engineer, [12] Submit to HQ Mats Lab for review and approval.
Development Division. [13] Approved by Regional Administrator or designee.
[4] Approved by Right of Way Plans Manager. [14] Per 23 CFR 635.111.
[5] Refer to Chapter 210 for approval requirements. [15] See the Hydraulics Manual for approvals levels.
[6] Final review & concurrence required at the region [16] Applies to regions with a Landscape Architect.
level prior to submittal to approving authority. [17] Applies to regions without a Landscape Architect.
[7] Final review & concurrence required at HQ prior to [18] Approved by State Traffic Engineer.
submittal to approving authority.
[19] Vacant.
[8] On Interstate projects, the Director & State Design
[20] Region Traffic Engineer or designee.
Engineer, Development Division, (or designee)
submits the approved design hearing summary to [21] The State Bridge and Structures Architect reviews
the FHWA for federal approval. (See Chapter 210.) and approves the public art plan (see Chapter
950 for further details on approvals).
[9] See Exhibit 300-1 for BOD Approvals.
[22] State Traffic Engineer or designee.

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Design Documentation, Approval, and Process Review Chapter 300

Exhibit 300-3 PS&E Process Approvals NHS (including Interstate) and Non-NHS

Headquarters or Region Approval

Item
Authority
DBE/training goals * ** Office of Equal Opportunity
Region; HQ Real Estate Services Office or HQ
Right of way certification for federal-aid projects***
Local Programs Right of Way Manager [7]
Region; HQ Real Estate Services Office or HQ
Right of way certification for state or local funded projects***
Local Programs Right of Way Manager
Railroad agreements HQ Design Office
Work performed for public or private entities * Region [1][2]
State force work * Region [3][4]
Use of state-furnished materials * Region [3][4]
Capital Program Development and
Work order authorization
Management [5]
Ultimate reclamation plan approval through DNR Region
Proprietary item use * [4][6] HQ Design Office
Mandatory material sources and/or waste sites * Region [4]
Nonstandard bid item use * Region
Incentive provisions HQ Construction Office
Nonstandard time for completion liquidated damages * HQ Construction Office
Interim liquidated damages * Transportation Data, GIS & Modeling Office

Notes:
FHWA PS&E Approval has been delegated to WSDOT unless otherwise stated differently in a Project
Specific PoDI S&O Agreement.
[1] This work requires a written agreement.
[2] Region approval subject to $250,000 limitation.
[3] Use of state forces is subject to $60,000 limitation and $100,000 in an emergency situation, as stipulated
in RCWs 47.28.030 and 47.28.035. Region justifies use of state force work and state-furnished materials
and determines if the work is maintenance or not. HQ CPDM reviews to ensure process has been
followed.
[4] Applies only to federal-aid projects; however, document for all projects.
[5] Prior FHWA funding approval required for federal-aid projects.
[6] The HQ Design Office is required to certify that the proprietary product is either: (a) necessary for
synchronization with existing facilities, or (b) a unique product for which there is no equally suitable
alternative.
[7] For any federal aid project FHWA only approves Right of Way Certification 3s (All R/W Not Acquired),
WSDOT approves Right of Way Certification 1s and 2s for all other federal aid projects.
References:
* Plans Preparation Manual
** Advertisement and Award Manual
*** Right of Way Manual

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Chapter 300 Design Documentation, Approval, and Process Review

Exhibit 300-4 Design to Construction Transition Project Turnover Checklist Example

This checklist is recommended for use when coordinating project transition from design to construction.
1. Survey
 End areas (cut & fill)
 Staking data
 Horizontal/Vertical control
 Monumentation/Control information
2. Design Backup
 Index for all backup material
 Backup calculations for quantities
 Geotech shrink/swell assumptions
 Basis of Design, Design decisions and constraints
 Approved Design Analyses
 Hydraulics/Drainage information
 Clarify work zone traffic control/workforce estimates
 Geotechnical information (report)
 Package of as-builts used (which were verified) and right of way files
 Detailed assumptions for construction CPM schedule (working days)
 Graphics and design visualization information (aerials)
 Specific work item information for inspectors (details not covered in plans)
 Traffic counts
 Management of utility relocation
3. Concise Electronic Information With Indices
 Detailed survey information (see Survey above)
 Archived InRoads data
 Only one set of electronic information
 “Storybook” on electronic files (what’s what)
 CADD files
4. Agreements, Commitments, and Issues
 Agreements and commitments by WSDOT
 RES commitments
 Summary of environmental permit conditions/commitments
 Other permit conditions/commitments
 Internal contact list
 Construction permits
 Utility status/contact
 Identification of the work elements included in the Turnback Agreement
(recommend highlighted plan sheets)
5. Construction Support
 Assign a Design Technical Advisor (Design Lead) for construction support

An expanded version of this checklist is available at:  www.wsdot.wa.gov/design/projectdev

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Design Documentation, Approval, and Process Review Chapter 300

Exhibit 300-5 Local Agency and Developer Approvals

Design
Design
Basis of Design Approval and
Analysis
Project Type (BOD) Project
Approval
Approval Development
Approval
Interstate
All projects FHWA FHWA FHWA
Highways (NHS) & (Non‐NHS)
Projects on limited access highways HQ Design HQ Design Region
Projects on managed access highways Region HQ Design Region

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Chapter 301 Design and Maintenance Coordination
301.01 Introduction
301.02 Communication
301.03 Incorporating Maintenance Considerations in Design
301.04 Documentation
301.05 References

301.01 Introduction
Maintenance plays an important role in the Washington State Department of Transportation’s
(WSDOT’s) asset management program by meeting the daily requirements of maintaining and
operating over 18,000 lane miles, approximately 2,000 miles of ramps and special-use lanes, and
over 3,700 bridge and culvert structures, as well as hundreds of other special-use sites vital to
the state’s transportation system. Activities in the highway maintenance program protect the
public infrastructure as well as provide services necessary for daily operation of the highway
system. Typical maintenance activities include patching potholes, cleaning ditches, painting
stripes on the roadway, repairing damage to guardrail, and controlling noxious weeds. In
addition to maintaining assets, operational services are also provided. They include plowing
snow, cleaning rest areas, responding to incidents, operating structures like draw bridges, and
operating traffic signals, lighting, and Intelligent Transportation Systems (ITS). This limited list
of maintenance and operational activities highlights the significant undertaking of maintaining
and operating the State Highway System as designed.

Highway maintenance and operations staff are unique stakeholders, because they utilize,
maintain, and operate the facilities’ engineering designs and constructs. Given the nature and
cost of maintenance work, as well as the exposure inherent in maintenance and operational
activities, it is important for designers to consider maintenance and operations staff as major
stakeholders in every project. It is also important for maintenance and operations staff to
understand the purpose of the project and to participate in determining the best method(s) to
keep it functioning as designed while maintaining their responsibilities outside of the specific
project limits.

This chapter provides multiple options to help improve coordination with maintenance and
operations staff during project design. These “best practices” are a culmination of responses
from Design Manual user surveys, interviews with maintenance and operations superintendents,
and various regional practices that have demonstrated potential improvement related to the
coordination of design and maintenance efforts and personnel. Note: The concepts and methods
presented herein do not replace any approved communication or documentation processes that
may be currently required by a WSDOT region during the project development process.

301.02 Communication
Communication is the most fundamental component of coordination. Executing communication
is often oversimplified by the phrase “communicate early and often.” In reality, effective
communication is significantly more complex. For example: Who are you communicating with,
what methods of communication are being used, what is being communicated, how are you
responding to communication, where is the communication taking place, and when does the
communication need to occur to maximize effectiveness?

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Design and Maintenance Coordination Chapter 301

The following sections highlight areas that may increase the necessary communication between
design and maintenance staff.

301.02(1) Maintenance Organizational Roles

The most important component of communication is knowing who you are communicating with
and what their role is within the organization. Just as engineering has multiple disciplines that
cover specific areas within engineering, WSDOT’s maintenance organization is also divided into
multiple discipline areas, each with focused expertise and specific needs that may be relevant
to a particular project.

When asking for maintenance input, it is not

sufficient to contact just the Area Maintenance
Office that covers that physical geographic area.
Depending on the scope of the project,
engineering must consult with the appropriate
maintenance discipline area. It is a project
management responsibility to properly identify
and communicate with the appropriate project
stakeholders (see EO 1032 – Project
Management). It should not be assumed that the
Area Maintenance Office will coordinate with all Access to maintain luminaire is provided through
use of full shoulder
other maintenance disciplines, unless agreed to
organizationally or identified within a particular Project Management Plan (PMP). The PMP
is the documentation mechanism for identifying the various contacts and their roles within
the project. Each region maintenance organization is different, but in general, the following
discipline areas are present:
• Area Maintenance
o Pavement
o Roadside vegetation control
o Rest area management
o Seasonal and emergent maintenance
needs
• Signal, Illumination, and ITS Maintenance
• Bridge
• Traffic Operational Maintenance
o Pavement markings
o Sign management
Striping crew restriping after patching pavement
o Incident response

To access a list of superintendents, go to:

 http://wwwi.wsdot.wa.gov/maintops/pdf/maintenanceofficephonelist.pdf

To access a list of maintenance performance measures, go to:

 http://www.wsdot.wa.gov/maintenance/accountability/default.htm

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301.02(2) Communicating Expectations

Project design is heavily influenced by the subprogram and scope of a particular project. While
this becomes a learned experience within engineering design, maintenance staff does not
routinely work within these types of funding and project constraints. It is important to identify
the type of project and elements that can be addressed under the particular subprogram, in
order to effectively manage expectations for
maintenance stakeholders participating in the
project. It is also important to redirect issues
presented by maintenance staff that may not
be appropriate for your project, but may meet
a future need. The project team should work
together with maintenance to redirect
identified issues to region Program
Management to evaluate their relevance for
other subprograms or future identified
projects, or determine if there are funding
mechanisms to include the requested Traffic control needs to maintain the roadside
feature(s) on the project in question.

301.02(3) Communication Timing

There are multiple constraints to consider when establishing the timing of maintenance
stakeholder input. What is the project timeline, when will maintenance involvement be most
effective, and which work season(s) are maintenance and operations staff involved with when
you need to communicate with them? Each one of these questions needs to be understood to
yield the most effective communication result.

This procession of snow plows clearing the roadway demonstrates the urgency of labor and equipment
necessary to maintain operations on the highway during certain seasons

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Maintenance staff has identified scoping through the 30% design phase as a critical period for
their input. The scoping phase presents opportunities to identify maintenance concerns and
adequately address them within the project scope and budget. The period between scoping
and 30% design presents opportunities to evaluate and refine options, as well as gain more
understanding of project constraints that may impact a previously identified or requested
maintenance feature. As the constraints and design trade-offs become evident, it is necessary
to review the impacts to maintenance needs and requests that were originally captured in the
project scope and ensure they are not impacted by constraints or the options under evaluation.

Maintenance staff are obligated to respond to immediate incidents and weather conditions.
They are not often able to delay their work functions and activities to make time for a design
project review. It is essential that designers understand this issue and plan for reviews through
scheduling techniques (see 301.03(1)(a)). In general, the best time to involve maintenance staff
is during their slower work seasons.

Maintenance responds to emergencies, which are more likely to occur during certain seasons

301.02(4) Communication Methods

Maintenance has identified field reviews as the primary and most effective method of
communication for their staff. Designers are strongly encouraged to perform multiple field
reviews with the appropriate maintenance disciplines. Depending on the size, scope, and
location of the project, it may be appropriate to first meet in the office and review the project
scope and plans, confirm and endorse the Pre-Activity Safety Plan, then proceed with the field
review. Field reviews are recommended at the following periods:

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• Scoping phase
• Prior to the 30% design milestone (may need multiple meetings to evaluate design
options)
• Each time a previously agreed-to maintenance feature is impacted through design
iterations, as appropriate
• Prior to other major design review milestones

Maintenance clearing highway from rockfall overburdening catchment area

A primary purpose for performing field reviews with maintenance is to assist with visualizing the
project and to understand existing conditions. When performing the field review, it is important
to emphasize the following:
• Reiterate the purpose of the project and subprogram, and discuss maintenance
expectations.
• Determine the deficiency being corrected and the understood contributing factors. It is
important to gain an understanding from maintenance staff on any other contributing
factors or physical conditions that engineers may not be aware of.
• Visualize the project with maintenance:
o What will be new?
o What will be removed?
o What will be replaced, and what is the replacement?
o Where will new features be located?
o How will project changes affect neighbors?

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• Determine whether the project can be operated and maintained with existing
equipment.
o It is necessary for design and maintenance staff to fully understand the impacts to
both the maintenance and project budgets to analyze and balance the obligations
for the investments as assets are identified on a project. For example, new lighting
means maintenance will be billed for the utility costs. Generally, this increased
cost has not resulted in increased funding.
- Will proprietary item requests be needed so maintenance can maintain
the project items with the tools and equipment they currently have?
- Will new equipment be needed, and who will fund that equipment
acquisition?
o What is the maintenance frequency for affected assets? Will this change?
o What are the environmental and permit restrictions related to the asset or
feature?
o How might maintenance physically maintain features to understand safety and
access needs for the asset or feature?
• Identify explicit action items for design and maintenance staff to follow up on as design
iterations continue.
• Document the outcomes of the field meeting, and follow up to ensure maintenance
needs are addressed, or provide specific explanations.

In order for maintenance to assist in brainstorming alternative options, engineering design

must explain the reasons and constraints behind the previous design options considered and
abandoned through the design iteration process.
• Provide maintenance stakeholders the reasons and justification behind design
decisions.
• Allow for the time and discussions necessary to brainstorm other options to provide
the desired accommodations and features, given the constraints and conflicting
performance outcomes identified.
• Before removing any previously discussed maintenance features, always discuss and
work on the issue with maintenance staff first.

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Cleaning bridge drains requires special equipment and traffic control

While independent reviews of plan sheets are meaningful for engineers, it may be an
inappropriate expectation that maintenance staff will see the same value. The repeated
familiarity of reviewing plan sheets is not necessarily present within the maintenance staff,
and plan review training may or may not be feasible for a given regional maintenance
organization based on staffing, workloads, and skill retention.

In some larger regional maintenance organizations, a liaison position has been designated for
designers to coordinate plan reviews. This approach has seen some success. However, this
liaison cannot possibly be aware of all comments/concerns for every maintenance discipline.
Don’t assume that coordinating plan reviews through the liaison meets the expectation for
maintenance stakeholder input. Always check with the various maintenance disciplines for
their preferred contacts and include those contacts within the PMP.

301.03 Incorporating Maintenance Considerations in Design

The intent of this section is to provide some project management options and potential
strategies or products to help manage the incorporation of maintenance considerations
into a design project.

301.03(1) Project Management and Review Strategies

Design iterations are necessary as information is gained throughout the design process.
Designers are constantly forced to balance competing stakeholder needs, regulatory
requirements, design criteria, performance outcomes, and physical and political constraints.
The following subsections include some recommended strategies for designers throughout
the course of a design project.

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301.03(1)(a) Project Management and Schedules

1. Include maintenance discipline representatives within the PMP, and identify their specific
roles and responsibilities within the design project.
• This is important for team members, to ensure their inclusion on interdisciplinary
decision making and brainstorming options for specific features that may affect
only a single or all maintenance disciplines.

2. Schedule the appropriate duration and timing within the project schedule to complete the
necessary field reviews with maintenance staff.
• There are multiple scheduling techniques that may assist you, ensuring this will be
well planned based on maintenance staff availability and changing work priorities.
Contingency activities, providing more activities detailing the effort, or expanding
the duration for single activities may all be appropriate. If uncertain how to best
represent the needed time within the schedule, consult the Region Project
Management and Reporting System (PMRS) Coordinator for options.

3. As the project works toward constructability reviews, be sure to include appropriate

durations for procuring materials.
• There have been reported instances where maintenance and operations staff has
been contacted to temporarily provide equipment while awaiting procurement and
acceptance. This creates additional work efforts for maintenance staff to install and
remove their equipment to keep a project operational, because inadequate
procurement timelines were identified during the design phase.
Note: Some regions have an internal policy that prohibits use of maintenance
equipment on a temporary basis due to poor execution and management of
procurement timelines. Designers should verify what options exist if procurement
timelines appear problematic in construction staging exercises.

Whenever possible, design should avoid creating environments that might be desirable to the
homeless, both for their safety and the safety of maintenance staff

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301.03(1)(b) Project Reviews

The skill sets of individuals throughout the department vary with experience and training.
Strictly utilizing independent plan reviews to gain maintenance stakeholder input may be
inappropriate. While field reviews are an optimal means of communicating and visualizing the
project with maintenance, it is not prudent to meet in the field for every change or design
iteration of a specific feature. However, design engineers frequently engage multiple
stakeholders on a project, and those stakeholders are generally provided visual aids and
descriptions in addition to a set of plans.

The same effort can be applied to the maintenance

stakeholders. Use pictures of completed products, or
generate 3D PDFs and/or working drawings, to better
illustrate and visualize the features under discussion.
Take the time to understand what matters regarding
a particular feature and how it will be maintained, and
ensure the illustrations provided depict the worst case
for their concerns, not the average. For example, if the
steepness of side slopes matters regarding how the
feature will be accessed or maintained, be sure to
depict how the slope will vary, including the steepest
portion, not the typical slope. Every effort should be
made to ensure stakeholders understand the
balancing act design is working through and how it
Vactor truck cleaning a catch basin placed
affects the various maintenance features or assets. directly under guardrail run

Maintenance staff should never be in a position to review project details from a plan sheet
without a meeting/discussion, examples, or other means of communicating what feature or
issues they are reviewing on the plan sheet. This effort will help ensure there are “no surprises”
for maintenance and operations staff when the planned project enters construction.

301.03(2) Maintenance Design Considerations –Tips, Tools, and End Products

There are multiple potential products that design teams should consider to effectively
document maintenance considerations. Note that some options presented in the following
subsections may be more effective if implemented on a regionwide basis. However, all options
can be described as project procedures and should be identified and explained within the PMP.

301.03(2)(a) Establish Maintenance Performance Measures

For a given corridor or project location, it may be advantageous to identify desired performance
measures and their established goal(s). Providing a performance-based outcome provides
something tangible for designers to evaluate when exploring options. These performance
objectives should be specific and state the actual needed outcome, not necessarily a proposed
solution (see annotated example in Exhibit 301-1).

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Exhibit 301-1 General Input Form with Listed Performance Objectives

301.03(2)(b) Evaluate Maintenance Lifecycle Cost

Designers should work with maintenance to understand the full life cycle cost for maintaining
a certain feature. Maintenance will need to provide and explain to design:
• The frequency of maintaining the asset
• Labor costs
• Material costs
• Traffic control costs
• Utility costs
• Additional equipment costs (cost to repair if equipment owned, rental costs, or
purchase cost of new equipment needed)
• Cost of procuring replacement parts for the asset

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Additionally, maintenance and operations staff should identify some qualitative risks and
opportunities associated with certain assets. Some opportunities, like the one presented in
Exhibit 301-2, may not be possible depending on material availability or funding restrictions.

It is important for designers to understand that some products may have a short shelf-life.
Procuring new replacement parts in the future may not be possible, which may result in a search
for used parts or the total replacement of the particular asset. These are future risks that need
to be identified so design engineers will understand what options or special provisions may be
required to help address the potential risks. Maintenance staff can help design understand the
history of different assets and
determine options that have been
successful for a given maintenance
location. Design engineers also need
to communicate the requirements
and disadvantages of proprietary
items specifically requested by
maintenance. While it may be the
desired product that maintenance is
familiar with, it may not be the best
product for what is being designed.

It is necessary to both determine

the life span for a particular asset
and utilize discounted cash flow
techniques to understand the Replacing a guardrail is not a simple activity
present worth of the future expenditures. The discounting process can be complex; however,
for the purposes of evaluating maintenance life cycle cost, it is acceptable to use a flat discount
rate applied to the sum of all future maintenance expenditures. In Exhibit 301-2, the asset life
span is 20 years, and the discount rate is approximately 80% (based on a 4% interest rate per
year). If the asset life span is different, then the discount rate will also change. To determine the
life span of a particular asset type and the approximate discount rate for that life span, contact
the Asset Management Group within the Capital Program Development and Management
Office.

After analyzing the life cycle cost to maintain a particular asset, and demonstrating an
understanding of the associated risks, design and maintenance staff can justify the best return
on the construction investment. While the primary intent of this process is to document
justification for an asset decision, it is important that region Maintenance is supplied with
the information as well. Providing this information during the design process can inform
maintenance budgetary scenarios. Allow sufficient time for maintenance to capture budget
impacts and apply for the necessary funding in the bi-annual maintenance budgeting process.

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Exhibit 301-2 Design Option Worksheet Showing Example of Life Cycle Cost Assessment

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Exhibit 301-2 Design Option Worksheet Showing Example of Life Cycle Cost Assessment (continued)

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Exhibit 301-2 Design Option Worksheet Showing Example of Life Cycle Cost Assessment (continued)

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Exhibit 301-2 Design Option Worksheet Showing Example of Life Cycle Cost Assessment (continued)

301.03(2)(c) CAE Design Tools

Projects create assets that need to be
maintained. The various CADD and
modeling programs used for
engineering design allow for significant
flexibility to show maintenance
considerations related to the project.
This is true even if a feature won’t be
physically built by the project, but we
want to ensure its visibility throughout
the design. Indicate maintenance work
zones and access routes within the
working files. Refer to the Electronic
Engineering Data Standards Manual for
symbology requirements and standards.
Ideal utility vault and Variable Message Sign access

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301.03(2)(d) Maintenance Review and Quality Control Products

There are a number of different ways to support design reviews and quality control for
maintenance features associated with a project. Some regions use maintenance review
checklists to remind designers and reviewers of common maintenance needs on projects
(see example in Exhibit 301-3).

Worksheets for each asset are another means to document the discussion, options considered,
and the decided outcome for a particular asset placed or retained within the project limits (see
example in Exhibit 301-2).

Even if these review and documentation

options are not specifically required by
region documentation and approval
processes, a decision to utilize these tools
can be made at the project level.

The established quality control and quality

assurance (QA/QC) procedure within each
region provides an additional process for
ensuring maintenance comments and
concerns have been addressed and the
agreed-on features are in place. This
procedure becomes increasingly important
at the 60%, 90%, and constructability review
milestones, where design iterations may
have neglected to account for impacts to
previously agreed-on features or treatments
specific to maintenance and operational
needs. Discuss increasing the visibility of
maintenance-related quality control within
the project or region QA/QC plan and
identify the assigned staff responsible for
quality control and quality assurance.
Poor utility vault access

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Exhibit 301-3 Excerpts from Olympic Region Review Checklist

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301.03(2)(e) Asset Management and Maintenance Owner’s Manual

Maintenance and operations staff will need to maintain the assets placed or retained within
a project location. It is important to be aware of the various asset management systems:
• Highway Activity Tracking System (HATS)
• Roadside Features Inventory Program (RFIP)
• Signal Maintenance Management System (SIMMS)
• Maintenance Productivity Enhancement Tool (MPET)
• Traffic Sign Management System (TSMS)

The asset management system reviews are necessary to confirm the assets present on a project,
as well as any identification numbers associated with the assets to track and list those that will
be removed, replaced, or remain. Work with the appropriate maintenance staff and confirm the
assets identified during field reviews with maintenance staff. Post-construction, any new assets
placed will need to be logged into the appropriate asset management system(s) by maintenance
or construction staff, depending on region procedures.

Maintenance and operations personnel have

experience maintaining a variety of products and
features on state highways. However, not every
asset is strictly typical for the maintenance
discipline or area responsible for maintaining or
operating it. Review the assets planned for
placement within a project and understand what
information maintenance crews may need to
adequately maintain the asset or feature. This
should include the following:
• Recommended equipment
• Frequency of maintenance activities
• Limits or boundaries (particularly for
stormwater BMPs)
• Access location and route Well-designed access for luminaire maintenance

• Any other relevant information discussed

with maintenance or supplied by the product provider, including information on brand,
make, and model of the asset

Information about these assets should be compiled into an Owner’s Manual for maintenance
to reference.
• The Owner’s Manual will be provided in hard copy, an editable electronic copy, and
static electronic versions.
• Electronic versions of the Owner’s Manual must be titled in the following format:
[YYYYMMDD]_Owner’s Manual_[route]_[MP Limits]_[Contract Number].
• Hard copies will be bound in a binder and labeled on the cover and binding with the
same information provided in the required PDF title.

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The Owner’s Manual versions will be supplied to both maintenance and the construction office,
upon contract advertisement. Note: This may not be necessary if needed content is captured
within the area’s Integrated Vegetation Management (IVM) Plan.

If changes occur during post advertisement for a particular asset or feature listed in the Owner’s
Manual, it is the responsibility of the construction office and maintenance to coordinate an
update of the Owner’s Manual, as appropriate. As the construction phase ends, after punch
list items are resolved, Maintenance staff should undergo a final review to ensure the Owner’s
Manual is complete and accurate.

301.03(2)(f) Maintenance Agreements

Some project locations may have multiple maintenance jurisdictions, at both the state and local
levels. In these circumstances, involve all maintenance jurisdictions throughout the planning
and design process. They can help you understand their capabilities and the reasonable
accommodations necessary for frequent maintenance operations. To understand the likely split
between local and state jurisdictions, refer to Chapter 1230 and the Conformed Agreement… for
the Construction, Operations and Maintenance Responsibilities…
 www.wsdot.wa.gov/localprograms/lag/construction.htm

Some maintenance and operations agreements between state and local agencies exist for
streets that are also state highways, and are important to the success of these projects. These
agreements may need to be created, updated, or replaced due to the nature of the project.
The potential agreements need to identify the maintenance, operational, and jurisdictional
boundaries, roles, and responsibilities of the parties entering into the agreement, including
liability, indemnification, and insurance. The Conformed Agreement (above) lists the likely split
of jurisdictional responsibilities. However, maintenance jurisdiction(s) may want to create an
operational plan or agreement for the infrequent maintenance functions that designs may not
be able to accommodate. It is also possible that one maintenance jurisdiction will be better
equipped to handle certain maintenance elements than another. It will be necessary to
document the split of maintenance responsibilities even if responsibilities remain the same
as those listed within the Conformed Agreement.

Agreements require a level of detail that will not be known early in project development, so
it is important to document trade-offs, benefits, and impacts with the affected maintenance
jurisdictions while early decisions are being made.

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Maintenance patching pavement at an intersection requires significant planning, night work, and traffic control

301.04 Documentation
Refer to Chapter 300 for design documentation requirements. Examples of documentation and
checklists can be found at:  www.wsdot.wa.gov/design/policy/default.htm

301.05 References
301.05(1) Federal/State Laws, Codes and Agreements
City Streets as Part of State Highways Guidelines Reached by the Washington State Department
of Transportation and the Association of Washington Cities on Interpretation of Selected Topics
of RCW 47.24 and Figures of WAC 468-18-050 for the Construction, Operations and Maintenance
Responsibilities of WSDOT and Cities for such Streets, 4-30-1997, amended 4-2-2013
 www.wsdot.wa.gov/localprograms/lag/construction.htm

301.05(2) Design Guidance and Supporting Information

A Policy on Geometric Design of Highways and Streets, AASHTO, current edition
Cost Estimating Manual for WSDOT Projects, M 3034, WSDOT
Electronic Engineering Data Standards, M 3028, WSDOT
Highway Runoff Manual, M 31-16, WSDOT
Maintenance Manual, M 51-01, WSDOT
Roadside Design Guide, AASHTO, current edition
Roadside Policy Manual, M 3110, WSDOT
Secretary’s Executive Order 1032, Project Management

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Chapter 305 Project Management
305.01 Introduction
305.02 Project Management
305.03 Project Management Tools
305.04 Cost and Risk Management
305.05 References

305.01 Introduction
The Washington State Department of Transportation (WSDOT) utilizes best practices to develop
project management plans to successfully deliver projects on schedule and within budget.
WSDOT’s project management process provides an organized approach to building collaborative
teams. Resources including methods, processes, tools, templates, and examples offer the
opportunity to enhance project management.

This chapter serves as a reference and gives a brief overview of project management resources
and links for your use. This chapter outlines the steps of project management. Project
management includes strategies to manage:
 Teams – identify roles and responsibilities; align team project goal
 Collaboration – engage internal and external stakeholders and participants
 Deliverables – identify what must be produced
 Tasks – plan and organize sequence and levels of effort work to provide the
deliverables
 Schedules – determine duration and task linkages
 Costs – plan and control project budget
 Risks – determine project exposure to threats and opportunities
 Integration and coordination of processes – eliminate waste
 Change – describe decision making, approving and reporting change
 Quality – assure, control and verify quality
 Communication – based on project needs, project team and external parties.

Effective project management must include a strong commitment to communication about the
project within and external to the design team. Following are descriptions and links to project
management resources.

Executive Orders 1032, 1038, and 1053 ensure a consistent process for practical design, project
management, and risk management statewide.

305.02 Project Management

Project management processes provide the framework for project managers and team
members to deliver projects on time and within scope and budget. Project management

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resources are consistent with a practical design approach and offer structure for organizing
collaborative teams to engage stakeholders and the community.

Exhibit 305-1 shows the project management process used to deliver projects. Each of the five
parts shown is briefly described in the sections that follow.

Exhibit 305-1 WSDOT Project Management Process

Monitoring
Initiating Planning Executing and Closing
Controlling

develop project take action - direct and monitor deliverables, prepare organized
organize team for
management plan and manage work and due dates, costs, and cessation activities;
success
work plan communications quality transition work or staff

305.02(1) Initiate and Align

Teams deliver projects; hence one of the first orders of business in project management is to
initiate and align the team. Our projects are successful based on the effectiveness of the team
delivering them. To that end initiating and aligning the team is an important early
accomplishment. Aligning the team establishes communications and responsibilities of the
project manager and team. The Initiate and Align worksheet is a tool that can be helpful in this
phase.

305.02(2) Planning the Work

Plan the Work is the portion of the project management process that produces the Project
Management Plan.

The Project Management Plan defines the project performance baseline – including
deliverables, schedule and budget plans – and the management methods used to deliver the
project. As we plan the work for our projects we integrate and coordinate processes in a manner
that optimizes resources and reduces waste. For example if your project requires an interchange
justification report (IJR), national environmental policy act (NEPA) documentation, or a value
engineering study (VE) coordinate and align these efforts in a manner that makes use of
common information and subject matter experts and in a way that ensures the need statements
and function work together for the project.

The performance baseline documents the team goals for project performance. Performance
baseline includes:
 Scope – the deliverables to be produced by the project team.
 Schedule – the logical sequence of work and related milestones.
 Budget – the allocation for the project.
 Risk – uncertainty that affects project objectives.

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The Project Management Plan includes management plans for Risk, Change, Communication,
Quality, Transition and Closure. These plans align the team toward uniform goals. A complete
project management plan considers how the project will start, how it will be executed,
monitored, and controlled, and how the project will close.

305.02(3) Executing the Work

The executing process is where we actually perform the planned work. During execution, we
coordinate our team, subject matter experts and others as necessary to produce the
deliverables. During execution, we ensure the integration of various project development and
design processes that are optimal for completing the required work and meeting the
performance objectives.

305.02(4) Monitoring and Controlling

As the work is being executed we track and report progress. If changes or course corrections are
required, we want to identify those and take appropriate action in a timely manner. As we
monitor progress and control variance we may need to take actions that include: developing and
implementing recovery strategies, updating the project management plan, implementing risk
response strategies and updating the risk assessment. Obtain change request approvals as
necessary and ensure the quality plan is being implemented. Report on the performance of the
team and provide early and meaningful communication to management, staff and team.

305.02(5) Closing the Project

As a project comes to an end it will either close or transition to a new phase. We want to
perform the closure and transition in an orderly and appropriate manner. This involves
demobilizing and reassigning staff and transferring resources or facilities.

Address the closure and transition phase of the project management process during creation of
the project management plan and the work plan.

At the end of the project it is helpful to review lessons learned and to reward and recognize the
team for successes. Capturing lessons learned and recognize people occurs throughout the
project however, the closure phase provides an opportunity to finalize this and bring it to
conclusion.

Project transitions can be aided by using the Deliverable Expectation Matrix which provides a
range of project development deliverables and the general order in which they will occur.

A project is complete after transition and closure is accomplished and the project manager is
released from responsibility for the project.

305.03 Project Management Tools

For an overview of project management, with links to the WSDOT project management process
and tools for delivering the WSDOT Capital Construction Program, see the following website:
 www.wsdot.wa.gov/projects/projectmgmt

The three more common tools are described below.

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305.03(1) WSDOT’s Master Deliverables List (MDL)

The Master Deliverables List (MDL) is a comprehensive listing of project elements. This list
serves as a starting point for creating the project Work Breakdown Structure (WBS) and ensures:
 Appropriate project deliverables are included in the project management plan and
schedule.
 A common vocabulary across project teams, region and Headquarters (HQ), and
specialty/support groups.

For additional information, see the MDL:

 www.wsdot.wa.gov/projects/projectmgmt/masterdeliverables.htm

305.03(2) Deliverables Expectation Matrix

The Deliverables Expectation Matrix (DEM) is another tool used to identify design project
deliverables. The DEM is a simpler presentation than the MDL and shows recommended
deliverables at project phases like 30% design. The DEM is here:
 www.wsdot.wa.gov/publications/fulltext/design/demintro.pdf

305.03(3) Project Management and Reporting System (PMRS)

The PMRS is a tool for effective and efficient management of design project schedules,
resources, and costs. The following website provides tools for project planning, work breakdown
structure (WBS) development, scheduling, and resource and cost management:
 http://wwwi.wsdot.wa.gov/planning/cpdmo/pmrs.htm

305.04 Cost and Risk Management

There are several WSDOT sources for cost estimating guidance, including:
 Strategic Analysis and Estimating:
 http://www.wsdot.wa.gov/Design/SAEO/
 Estimating Information
 http://www.wsdot.wa.gov/Projects/ProjectMgmt/RiskAssessment/Information.htm
 Cost Estimating Manual
 http://www.wsdot.wa.gov/publications/manuals/m3034.htm

Risk management, as an integral part of project management, occurs regularly.

With proactive risk management, projects are monitored to assess and document risks and
uncertainty. For more information on risk planning and risk management, see:
 www.wsdot.wa.gov/publications/fulltext/cevp/projectriskmanagement.pdf

For more information on risk assessment, see:

 www.wsdot.wa.gov/projects/projectmgmt/riskassessment/

Document each estimate review in the Project File, and clearly show any changes made to the
estimate as a result of the review.

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Chapter 305 Project Management

305.05 References

305.05(1) Federal/State Laws and Codes

23 United States Code (USC) 106, Project approval and oversight

305.05(2) WSDOT Policies

Directives, Executive Orders, Instructional Letters, Manuals, and Policy Statements
 http://wwwi.wsdot.wa.gov/publications/policies/default.htm

Executive Order E 1032, Project Management

 http://wwwi.wsdot.wa.gov/publications/policies/fulltext/1032.pdf

Executive Order E 1038, Enterprise Risk Management

 http://wwwi.wsdot.wa.gov/publications/policies/fulltext/1038.pdf

Executive Order E 1053, Project Risk Management and Risk Based Estimating
 www.wsdot.wa.gov/publications/fulltext/cevp/1053policy.pdf

Executive Order E 1090, Moving Washington Forward: Practical Solutions

 http://wwwi.wsdot.wa.gov/publications/policies/fulltext/1090.pdf

Executive Order E 1096, WSDOT 2015–17: Agency Emphasis and Expectations

 http://wwwi.wsdot.wa.gov/publications/policies/fulltext/1096.pdf

Executive Order E 1082, Business Practices for Moving Washington

 http://wwwi.wsdot.wa.gov/publications/policies/fulltext/1082.pdf

Policy Statement P 2047.00 "Estimating Project Budget and Uncertainty"

 http://wwwi.wsdot.wa.gov/publications/policies/fulltext/2047.pdf

Project Delivery Memos

 www.wsdot.wa.gov/design/projectdev/memos.htm

305.05(3) WSDOT Project Management References

Project Management Guide:
 http://www.wsdot.wa.gov/Projects/ProjectMgmt/OnlineGuide/ProjectManagementOnlineGuide.htm

Project Management Glossary:

 www.wsdot.wa.gov/publications/fulltext/projectmgmt/pmog/pm_glossary.pdf

Glossary for Cost Risk Estimating Management:

http://www.wsdot.wa.gov/publications/fulltext/CEVP/Glossary.pdf

Cost Estimating Manual for Projects:

 http://www.wsdot.wa.gov/publications/manuals/fulltext/M3034/EstimatingGuidelines.pdf

Project Risk Management Guide:

 www.wsdot.wa.gov/projects/projectmgmt/riskassessment/default.htm

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Chapter 310 Value Engineering
310.01 General
310.02 Statewide VE Program
310.03 VE Procedure
310.04 Value Engineering Job Plan
310.05 Project Management Accountability
310.06 Documentation
310.07 References

310.01 General
Value engineering (VE) is a systematic review of a project by a multidisciplinary team not directly
involved in the planning and development phases of the project. The VE process includes
consideration of design; construction; maintenance; contractor; state, local, and federal
approval agencies; other stakeholders; and the public.

Properly timing a Value analysis influences its benefits. Value analyses are typically conducted
fairly early in project development to identify ideas to reduce cost and; refine scope. Section
310.02(3) VE Analysis Timing, of this chapter offers additional information about timing.

A VE analysis 1 may be applied as a quick-response study to address a problem or as an integral

part of an overall organizational effort to stimulate innovation and improve performance
characteristics.

Project managers are accountable for ensuring their projects meet all applicable value
engineering requirements. In addition, local programs projects are accountable for ensuring
they comply with Local Agency Guidelines requirements. In all cases, when a VE study is
completed, the project manager is accountable for completing, signing, and submitting the VE
Recommendations Approval Form.

310.02 Statewide VE Program

310.02(1) Annual VE Plan

The State VE Manager coordinates annually with the Capital Program Development and Region
VE Coordinators to prepare an annual VE Plan, with specific projects scheduled quarterly. The VE
Plan is the basis for determining the projected VE program needs, including team members,
team leaders, consultants, and training. The Statewide VE Plan is a working document that
reflects coordination between Headquarters (HQ) and the regions to keep it updated and
projects on schedule.

1
The terms “value management”, “value engineering”, “value study” and “value analysis” are used
interchangeably.

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310.02(2) Selecting Projects for VE Analysis

310.02(2)(a) Requirements

WSDOT projects for VE studies may be selected from any of the categories identified in the
Highway Construction Program, including Preservation and Improvement projects, depending
on the size and/or complexity of the project. In addition to cost, other issues adding to the
complexity of the project design or construction are considered in the selection process. These
include projects that have critical constraints, difficult technical issues, expensive solutions,
external influences, and complicated functional requirements, regardless of the estimated
project cost.

WSDOT may conduct VE analyses on any projects the project manager determines will benefit
from the exercise. In addition, WSDOT conducts VE analyses for all projects as required by the
criteria set forth in Federal Highway Administration (FHWA) Value Engineering Policy Order.
1. WSDOT policy requires a value engineering analysis for:
 Any project with an estimated cost (which includes project development, design,
right of way, and construction costs) of $25 million or more, regardless of funding;
 Each bridge project located on or off of the federal-aid system with an estimated
total cost of $20 million or more (WSDOT policy is to conduct a VE analysis
regardless of funding source); and
 Any other projects the Secretary or FHWA determines to be appropriate.
2. In addition to the projects described above, WSDOT strongly encourages a VE analysis on
other projects where there is a high potential for cost savings or improved project
performance or quality. Projects involving complex technical issues, challenging project
constraints, unique requirements, and competing community and stakeholder objectives
offer opportunities for improved value by conducting VE analyses.
3. Any use of Federal-Aid Highway Program (FAHP) funding on a Major Project2 requires that a
VE analysis be conducted. In some cases, regardless of the amount of FAHP funding, a
project team may be required to perform more than one VE analysis for a Major Project.
4. After completing the required VE analysis, if the project is subsequently split into smaller
projects in final design or is programmed to be completed by the advertisement of multiple
construction contracts, an additional VE analysis is not required. However, splitting a project
into smaller projects or multiple construction contracts is not an accepted method to avoid
the requirements to conduct a VE analysis.
5. WSDOT may require a VE analysis to be conducted if a region or public authority encounters
instances when the design of a project has been completed but the project does not
immediately proceed to construction.
a. If a project meeting the above criteria encounters a three-year or longer delay prior to
advertisement for construction, and a substantial change to the project’s scope or

2
Based on the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU), signed into law on
August 10, 2005, a Major Project is defined as "a project with a total estimated cost of $500 million or more that is receiving financial
assistance." FHWA also has the discretion to designate a project with a total cost of less than $500 million as a Major Project.

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Chapter 310 Value Engineering

design is identified, WSDOT may require a new VE analysis or an update to the previous
VE analysis; or
b. If a project’s estimated cost was below the criteria identified above but the project
advances to construction advertisement, and a substantial change occurs to the
project’s scope or design, causing an increase in the project cost so that it meets the
criteria identified above and results in a required re-evaluation of the environmental
document, WSDOT requires that a VE analysis be conducted.
6. When the design of a project has been completed but the project does not immediately
proceed to construction, the requirement to conduct a VE analysis is considered to be
satisfied, or not necessary, if:
a. A project met the criteria identified above and had a VE analysis conducted, and the
project advances to advertisement for construction without any substantial changes in
its scope or its design; or
b. A project’s estimated cost initially fell below the criteria identified above, but when
advancing to advertisement for construction, falls above the criteria due to inflation,
standard escalation of costs, or minor modifications to the project’s design or contract.

Other projects that should be considered for value engineering have a total estimated cost
exceeding $5 million and include one or more of the following:
 Alternative solutions that vary the scope and cost
 New alignment or bypass sections
 Capacity improvements that widen the existing highway
 Major structures
 Interchanges
 Extensive or expensive environmental or geotechnical requirements
 Materials that are difficult to acquire or that require special efforts
 Inferior materials sources
 New/Reconstruction projects
 Major traffic control requirements or multiple construction stages

310.02(3) VE Analysis Timing

310.02(3)(a) When to Conduct the VE Analysis

Timing is very important to the success of the VE analysis. A VE analysis should be coordinated
with other project development activities. For example, a project requiring an Access Revision
Report (ARR), NEPA and a VE should consider how to best integrate the processes with
development of project need statements.

Optimizing the timing of a VE analysis minimizes impacts of approved recommendations on

previous commitments (agency, community, or environmental) and project’s scope. VE analyses
can also be coordinated with project risk assessments.
See  www.wsdot.wa.gov/design/saeo/

Benefits can be realized by performing a VE analysis at any time during project development;
however, the WSDOT VE program identifies the following three windows of opportunity for
performing a VE analysis.

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1. Scoping Phase

Early in preliminary engineering is a good time for value analysis consideration. This is a time to
consider alternatives or design solutions with a high potential for implementing VE
recommendations. At the conclusion of the VE study, the project scope, preliminary costs, and
major design decisions are informed by the recommendations.

When conducting value engineering during the scoping phase of a project, the VE analysis
focuses on project drivers. This stage often provides an opportunity for community engagement
and building consent with stakeholders.
2. Start of Design

At the start of design, the project scope and preliminary costs have been established and major
design decisions have been made. Some Plans, Specifications, and Estimates (PS&E) activities
may have begun, and coordination with support groups and subject matter experts is underway.
At this stage, the project scope, costs, and schedule define the limits of the VE analysis. There is
opportunity to focus on the technical issues of the design elements.
3. Design Approval

After Design Approval, most of the important project decisions have been made and the
opportunity to affect the design is limited. Provided there is time to incorporate VE
recommendations, the VE analysis may likely focus on constructability, construction sequencing,
staging, traffic control, and significant design issues.

An additional VE analysis may be beneficial late in the development stage when the estimated
cost of the project exceeds the project budget. The value engineering process can be applied to
the project to lower the cost while maintaining the value and quality of the design.

310.02(4) VE Program Roles and Responsibilities

310.02(4)(a) Region VE Coordinator
 Identifies region projects for VE analyses (from Project Summaries and available
planning documents).
 Makes recommendations for timing of the VE analysis for each project.
 Presents a list of the identified projects to region management to prioritize into a
regional annual VE Plan.
 Identifies potential team facilitators and members for participation statewide.

310.02(4)(b) State VE Manager

 Reviews regional VE Plans regarding content and schedule.

310.02(4)(c) State VE Coordinator

 Incorporates the regional annual VE Plans and the Headquarters Plan to create the
Statewide VE Plan.
 Prepares annual VE Report.
 Maintains policy documents for the department.
 Coordinates studies.

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Chapter 310 Value Engineering

 Arranges training for future VE team leaders and members.

310.02(4)(d) VE Team Leader

The quality of the VE analysis largely depends on the skills of the VE team leader. This individual
guides the team’s efforts and is responsible for its actions during the analysis. The VE team
leader should be knowledgeable and proficient in transportation design and construction and in
the VE analysis process for transportation projects.

The VE team leader’s responsibilities include the following:

 Plans, leads, and facilitates the VE study.
 Ensures proper application of a value methodology.
 Follows the Job Plan.
 Guides the team through the activities needed to complete the pre-study, the VE
study, and the post-study stages of a VE study.
 Schedules a pre-workshop meeting with the project team and prepares the agenda for
the VE study.

Team leaders from within WSDOT are encouraged, but not required, to be certified by the
Society of American Value Engineers (SAVE) as an Associate Value Specialist, Certified Value
Specialist (CVS) or as a Value Methodology Practitioner (VMP). Team leadership can be supplied
from within the region, from another region, or from Headquarters. A statewide pool of
qualified team leaders is maintained by the State VE Coordinator, who works with the Region VE
Coordinator to select the team leader.

Consultants who lead VE teams are required to be SAVE certified.

310.02(4)(e) VE Team Members

The VE teams are usually composed of six to ten people with diverse expertise relevant to the
project under study. The team members may come from regions; Headquarters; other local,
state, or federal agencies; or the private sector.

Team members are not directly involved in the planning and development phases of the project.
They are selected based on the expertise needed to address major functional areas and critical
high-cost issues of the study. All team members must be committed to the time required for the
study. It is desirable for team members to have attended Value Engineering Module 1 training
before participating in a VE study.

310.03 VE Procedure
The WSDOT VE analysis uses the Seven-Phase Job Plan shown in Exhibit 310-1. A detailed
discussion of how each phase is supposed to be conducted can be found in the document, Value
Methodology Standard and Body of Knowledge, developed by SAVE International, The Value
Society. This document can be downloaded at the SAVE website:  www.value-eng.org/

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310.03(1) Pre-Study Preparation

To initiate a VE study, the project manager submits a Request for Value Engineering Study form
to the Region VE Coordinator at least two months before the proposed study date. The form is
located on the WSDOT value engineering website:
 www.wsdot.wa.gov/design/valueengineering/tools/
The Region VE Coordinator then works with the State VE Coordinator to determine the team
leader and team members for the VE study. Contacts are listed on the WSDOT value engineering
website:  www.wsdot.wa.gov/design/valueengineering
The design team prepares a study package of project information for each of the team
members. (A list of potential items is shown in Exhibit 310-2). Work with the State VE
Coordinator for the best/most concise list of materials to send to the team members. If the
package is provided via a network drive or FTP site, make sure the materials are well titled and
sorted in a well-titled file structure. The VE team members should receive this information or a
link to this information at least one week prior to the study so they have time to review the
material.
The region provides a facility and the equipment for the study (see Exhibit 310-2).

310.03(2) VE Analysis Requirements

The time required to conduct a VE analysis varies with the complexity and size of the project,
but typically ranges from three to five days. The VE team leader working with the project
manager will determine the best length of time for the study.
The VE analysis Final Report includes an executive summary; a narrative description of project
information; the background, history, constraints, and controlling decisions; the VE team’s focus
areas; a discussion of the team’s speculation and evaluation processes; and the team’s final
recommendations. All of the team’s evaluation documentation, including sketches, calculations,
analyses, and rationale for recommendations, is included in the Final Report. A copy of the Final
Report is to be included in the Project File. A copy of the report is also provided to FHWA for
projects on the National Highway System or federal-aid system.

Post-VE analysis activities include:

 The Project Manager and Project team are responsible for:
Implementation and evaluation of the approved recommendations.
Documentation of reasons recommendations were not implemented.

310.03(3) Implementation (Phase 7 of VE)

As soon as possible, preferably no more than two weeks following the VE analysis, the project
manager reviews and evaluates the VE team’s recommendation(s). The project manager
completes the VE Recommendation Approval form included in the Final Report and returns it to
the Statewide VE Manager.
Recommendations not approved or modified by the project manager require a brief justification
in the VE Recommendation Approval form.
The project manager sends the completed VE Recommendation Approval form to the State VE
Manager following receipt of the Final Report and not later than September 1 of each year,
whichever comes first, so the results can be included in WSDOT’s annual VE Report to FHWA.

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Chapter 310 Value Engineering

Exhibit 310-1 Seven-Phase Job Plan for VE Studies

VE Study Phase Job Plan

1. Information Gather project information, including project commitments and

constraints.
 Investigate technical reports and field data
 Develop team focus and objectives

2. Function Analysis Analyze the project to understand the required functions.

 Define project functions using active verb/measurable
noun context
 Review and analyze these functions to determine which
need improvement, elimination, or creation to meet
project goals

3. Creative Generate ideas on ways to accomplish the required functions that

improve project performance, enhance quality, and lower project
costs.
 Be creative
 Brainstorm alternative proposals and solutions to lower
project costs, improve project performance, and enhance
quality

4. Evaluation Evaluate and select feasible ideas for development.

 Analyze design alternatives, technical processes, and life
cycle costs

5. Development Develop the selected alternatives into fully supported

recommendations.
 Develop technical and economic supporting data to prove
the benefits and feasibility of the desirable concepts
 Develop team recommendations (long-term as well as
interim solutions)

6. Presentation Present the VE recommendation to the project stakeholders.

 Present the VE recommendation to the project team and
region management in an oral presentation
 Provide a written report

7. Implementation The decision to implement or not implement recommendations is

documented in the signed VE Recommendation Approval form.
The Project Manager implements approved recommendations.

Note: Phases 1–6 are performed during the study; see Value Standard and Body of Knowledge for
procedures during these steps.

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Exhibit 310-2 VE Analysis Team Tools

Project-Related Input* and Design Resources (Study Package)

Project Management Plan
Vicinity map
Aerial photos
Large-scale aerial photographs
Pertinent maps - Land use, contours, quadrant, etc.
Crash data with collision analysis
Existing as-built plans
Design file
Cross sections and profiles
Environmental documents Environmental constraints, and commitments
Estimates (and associated Basis Of Estimate)
Geotechnical reports
Hydraulic Report
Plan sheets
Quantities
Right of way plans
Bridge List/Bridge condition report
Design Manual
Field Formulas and Field Tables
Standard Plans
Standard Specifications
State Highway Log
Other manuals as needed

Study-Related Facilities and Equipment

AASHTO Green Book
Calculators
Computer (with network if available) / projector
Easel(s) and easel paper pads
Marking pens
Masking and clear tape
Power strip(s) and extension cords
Room with a large table and adequate space for the team
Scales, straight edges, and curves
Telephone
Vehicle or vehicles with adequate seating to transport the VE team for a site visit**

*Not all information listed may be available to the team, depending on the project
stage. Work with your Region VE Coordinator or the State VE Coordinator to verify that
all needed information is available.

**If a site visit is not possible, perform a “virtual” tour of the project.

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310.04 Value Engineering Job Plan

The VE process is comprised of a 6-step Job Plan. FHWA adds a “7th” step known as
implementation. Exhibit 310-3 depicts the process for Value Engineering. An interactive version
of this exhibit is available at:

 http://www.wsdot.wa.gov/publications/fulltext/CEVP/VE_JobPlan.pdf
Exhibit 310-3 Value Engineering Job Plan

310.05 Project Management Accountability

Project Managers are required to make a determination for each VE recommendation. To that
end, project managers, in consultation with their project teams, support staff, other
management support, and subject matter experts, decide the action to be taken for each
recommendation.

310.06 Documentation
Refer to Chapter 300 for design documentation requirements.

The following value engineering documentation is required:

 Project File – Value Engineering Final Report
 Design Approval – Design Documentation Package for Approval – the Value
Engineering Recommendation Approval Form
 Project File – Value Engineering Recommendation Approval Form

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310.07 References

310.07(1) Federal Laws and Codes

Title 23 U.S.C. Section 106(e) – Value Engineering Analysis

Title 23 CFR Part 627 – Value Engineering

MAP-21 (Moving Ahead for Progress in the 21st Century), Section 1503

Circular A-131, Office of Management and Budget (OMB)

 http://www.whitehouse.gov/omb/circulars_a131

FHWA Value Engineering Policy

 https://www.fhwa.dot.gov/legsregs/directives/orders/13111b.cfm

310.07(2) Design Guidance

Value Engineering for Highways, Study Workbook, U.S. Department of Transportation, FHWA
Value Standard and Body of Knowledge, SAVE International, The Value Society:
 http://www.value-eng.org/

WSDOT Value Engineering website:

 www.wsdot.wa.gov/design/valueengineering/

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Chapter 320 Traffic Analysis
320.01 General
320.02 Design Year and Forecasting Considerations
320.03 Traffic Analysis Software
320.04 Travel Demand Forecasting
320.05 Traffic Impact Analysis (TIA)
320.06 TIA Scope
320.07 TIA Methods and Assumptions Document
320.08 TIA Methodologies
320.09 TIA Mitigation Measures
320.10 TIA Report
320.11 References

320.01 General
This chapter is intended to address policy-related issues associated with WSDOT multimodal
traffic analysis. It is not intended to address the specifics of demand forecasting; mesoscopic,
analytical/deterministic, stochastic microsimulation; or safety performance analyses. For those
items, see the latest versions of the Highway Capacity Manual, Traffic Analysis Procedures
Manual (TAPM), and Highway Safety Manual (HSM).

Traffic analysis is intended to produce information for decision makers; it is not intended as a
stand-alone tool for making decisions. Consideration of empirical data, similar traffic situations,
studies, local knowledge, and seasoned traffic engineering and planning experience can also add
to a pool of traffic information that is provided to decision makers.

Traffic analysis is either “operational” or “planning” in nature. Operational analysis is associated

with engineering concepts focusing on near-term or existing/opening year, while planning
analyses are generally focused on a horizon year or interim phase years. Planning-level analyses
are also used to determine impacts for environmental documentation phases of Environmental
Assessment (EA) or Environmental Impact Statement (EIS) work. Much caution should be used
when operational tools are used with planning-level future year projection data.

Be aware that operational models were not primarily intended for use with planning-level future
year projected volumes, but there is a need to understand the difference between proposed
future scenarios. Therefore, operational models need to use data from forecasting models, but
analysts need to do so with an understanding of the imperfections.

Forecasting demand volumes 20 years into the future can be difficult to do well, so there should
be little expectation that intersection turning movement projection-related traffic analyses by
themselves will be sufficient to produce actionable designs. Consequently, some future year
Measures of Effectiveness (MOEs) such as turn lane queue length should not be considered
accurate, but they may be useful when comparing various scenarios if the reported differences
are substantial.

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With the aforementioned limitations, project-specific traffic volumes, forecasts, and system
capacities are used to establish the extent of improvements needed for facilities to operate
acceptably from year of opening or through interim phases and, eventually, through to the
horizon year; for example: Number of general purpose/HOV/HOT lanes
• Length and number of ramp or auxiliary lanes
• Intersection or interchange spacing
• Channelization
• Signal timing
• Right of way needs
• Roundabout design parameters
• Width of sidewalks
• Extent of bike lanes
• Ferry holding lanes

Traffic analysis should examine multimodal access, mobility, and safety objectives; project
benefits and costs; development impacts; and mitigation needs.

Not all projects will require the same level of effort. The specific depth and complexity of
a traffic analysis will depend on a variety of factors, including:
• Project proponents (federal, tribal, state, local, and private sector)
• Legal requirements (laws, regulations, procedures, and contractual obligations)
• Lead agency
• Purpose or scope of the traffic analysis
• Data availability
• Time of day (am/pm peak hour or other)
• Funding
• ROW availability

For projects that fall under FHWA approval, coordinate with the Headquarters (HQ) Traffic
Office for concurrence on traffic analysis details. Other projects can be coordinated through
region Traffic offices. (See Chapter 300 for FHWA oversight and approval policy.)

320.02 Design Year and Forecasting Considerations

Project evaluation requirements can be (1) focused on near-term functionality, (2) contain
interim phases, and/or (3) require a long-term focus. The project proponent can be the state
(WSDOT or other state agencies) or developers (other public agencies or private concerns).

For Access Revision Reports (AARs), the design year and multimodal travel demand forecasting
methodologies are to be documented by the project stakeholders in the Methods and
Assumptions (M&A) Documents.

Guidance on the horizon year and interim design year(s) for projects is given in Chapter 1103,
Design Controls. When selecting horizon year and interim design year phases, stakeholders need
to consider the regional significance of a proposed project, how it functions within the existing
system, and the expected lifespan. The traffic analysis for developer-related projects will
typically focus on existing conditions and the build-out year of the proposed project. Some

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larger developer projects will need to be evaluated in multiple phases, as they have the
potential to significantly impact the transportation system and will thus require a longer-term
focus. Mitigation measures may also be phased with these projects.

Project teams are encouraged to consider the strategic importance, economic potential,
network constraints, and investment scale when determining the analysis methodologies for
project phasing, design year, and forecasts. With acceptance/concurrence by the Traffic Office
of purview,1 the following are possible approaches to be used individually or in concert to
develop future year demand volumes:
• Travel demand models
• Trend line projections
• Cumulative impacts
• Limitations of the surrounding network

320.03 Traffic Analysis Software

With acceptance by the Traffic Office of purview, use the least complex and data-intensive
software deemed reasonable for any given project. Agreement for software and versions must
be documented in the study’s M&A. Use the latest version sanctioned by WSDOT HQ Traffic.
• For near-term analysis of locations that do not require an understanding of interactions
between various transportation systems, Sidra, Rodel, Synchro, and HCS are the
primary analytical tools.
• For systemwide multimodal complex forecasting, EMME3, TransCad, and Visum are the
primary tools.
• For choosing between scenarios involving multimodal traffic and/or where various
transportation system elements interact, CORSIM, Vissim, or Dynameq are the primary
tools.

The software mentioned above may have version limitations due to WSDOT purchased rights
and contract limitations. For details about these and other traffic analysis software used by
WSDOT, see the Traffic Analysis Procedures Manual or contact the region or HQ Traffic Office.

320.04 Travel Demand Forecasting

Designers, planners, and analysts need to be aware of the practical limitations of the selected
method of multimodal traffic demand forecasting and should consider the impact of demand
uncertainty when conducting analyses and drawing conclusions from those analyses. Special
attention should be given to any post-processing efforts. For guidance in the selection of
analysis methodology, refer to the Traffic Analysis Procedures Manual. Following are brief
descriptions of the four main methods for demand forecasting.

320.04(1) Travel Demand Models

For the vast majority of projects, this will be the proper approach for developing future year
demand volumes. However, caution should be taken when using this approach to draw

1
See Chapter 300 and the Federal-Aid Highway Program Stewardship and Oversight Agreement: Generally, region
for non-Highways of Statewide Significance (HSS) or non-National Highway System (NHS), and Headquarters for
HSS and NHS.

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conclusions from operational model Measures of Effectiveness (MOEs) that are based on such
forecasts, because specific and accurate turning movement volumes are needed to produce
credible MOEs. Forecast models are most commonly used to produce general volumes that
can help traffic planners evaluate and compare the relative merits of potential solutions
against each other.

320.04(2) Trend Line Projections

Where travel demand models are not established or are otherwise considered inadequate,
trend data can be used but must be constrained by system flow limitations. Trend line growth
cannot account for peak spreading when traffic demand exceeds system supply. Use with
caution and consult the HQ Transportation Data & GIS Office (TDGO) for further details
about this method and any inherent limitations.

320.04(3) Cumulative Impacts

This method is typically used to forecast volumes in areas that demonstrate uniform growth and
exhibit only minor changes and marginal impacts to the region. It is also useful for analyzing
growth in suburban areas that are experiencing rapid development, as other methods may
not be as reliable. The basic concept is to add volumes for developments to the trending
background traffic growth. The comprehensive plan for such areas should be consistent with
the expected growth predicted by a project (and include other anticipated projects) in order to
result in a reasonable estimate of cumulative impacts. Use with caution due to an inability to
fully account for secondary impacts like future environmental issues, local network connectivity,
public services, and multimodal demands.

320.04(4) Limitations of the Surrounding Network

For projects that contain infrastructure of particular importance, extraordinary expense, life span
expectancy beyond 20 years, or where travel demand will likely always exceed transportation
system capacity constraints, give consideration to the concept of facility capacity balancing
within the context of the larger transportation system.

This approach needs to demonstrate that the maximum amount of upstream traffic flowing into
a project, as well as all project-area traffic flowing into downstream sections, can be handled
acceptably. This does not require traditional travel demand forecasting, which has a limitation of
about 20 years. Instead, it requires a sensitivity approach where maximum up- and downstream
flows are used to right-size the project area’s proposed improvements. The simplest example is
the SR 520 Floating Bridge: constraints on either end of the bridge limit the usefulness of adding
more lanes on the bridge.

TIAs and ARRs (see Chapter 550) shall clearly describe the methodology and process used to
develop forecasts in support of a proposed project’s analysis. For example, include only those
projects that:
• Are on the six-year Transportation Improvement Plan.
• Are fully funded.
• Have entered the environmental review process.

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320.05 Traffic Impact Analysis (TIA)

TIA is a term used for all analyses that are not structured ARRs (see Chapter 550) or planning-
level efforts like corridor studies. The quality and level of service2 for state-owned and state-
interest facilities shall be based upon MOEs that support the project purpose and need. They
shall also be developed and presented in accordance with the latest versions of the Highway
Capacity Manual (HCM), FHWA Traffic Analysis Toolbox, Traffic Analysis Procedures Manual, and
WSDOT Vissim Protocol.

For some example MOEs, see the FHWA MOE List, which describes measures typically used for
analyzing state and local agency facilities such as freeway segments, signalized intersections,
ramp terminals/junctions, sidewalks, and transit services.

Depending on the facility and when HCM Level of Service MOE is used, WSDOT thresholds are
“C” for rural and “D” for urban non-NHS facilities, unless a WSDOT region specifies otherwise
for specific route segments. (See each WSDOT region for details.) Refer to the WSDOT State
Highway Log for a determination of existing route segment definitions for urban or rural status.

Depending on the project type and purpose, multimodal MOEs may be employed.

320.05(1) Updating an Existing TIA

TIAs require either updating or a sensitivity analysis if they become more than 3 years old;
however, a TIA will require updating sooner in rapidly developing areas. TIAs can avoid such
update efforts in slowly developing areas. To determine if an update is required, an assessment
of critical infrastructure functionality must be documented.

If the amount or character of traffic in the study area is significantly different from an earlier
analysis, an update will be required. The definition of significant is 10% (volume, flow rate, travel
time, delay, density, or other key MOEs) where existing operations are currently acceptable. If
they are not currently acceptable, the threshold is reduced to 5%. In cases where greater than
10% change or failed MOEs have been found, consultation and concurrence with WSDOT Traffic
Office of purview is required to avoid a full ARRs or TIA update.

Developer-initiated TIAs are typically valid for 5 or 6 years, as that is the window provided under
the Growth Management Act for concurrency. The Development Services Office should be
consulted regarding the need for updates to TIAs for developer, tribal, and local agency projects.

320.06 TIA Scope

To establish the appropriate scope, consultation between the lead agency, WSDOT, and those
preparing the TIA is encouraged before beginning work. TIA-required elements can be found
in the Traffic Analysis Procedures Manual (an abbreviated list is provided below). Note: For
developer-initiated TIAs, the local agency may prescribe the scope of the TIA per the local
agency’s adopted standards.

2
WSDOT sets level of service (LOS) standards for state highways and ferry routes of statewide significance (HSS)
based on RCW 47.06.140(2). Regional transportation planning organizations (RTPOs) and WSDOT jointly develop
and RTPOs establish LOS standards for regionally significant state highways and ferry routes (non-HSS) based on
RCW 47.80.030(1)(c).

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320.06(1) TIA Boundaries

The traffic impacts of local streets and roads can impact intersections on state highway facilities.
In these cases, include in the TIA an analysis of adjacent local facilities (driveways, intersections,
main lines, and interchanges) upstream and downstream of the intersection with the state
highway. A “lesser analysis” may include obtaining traffic counts, preparing signal warrants, or
a focused TIA. For developer projects, the boundaries of the analysis (such as the city limits) may
be determined in consultation with local agencies and WSDOT. For further guidance, consult the
Traffic Analysis Procedures Manual and Development Services Manual.

320.06(2) Traffic Analysis Scenarios

WSDOT must understand the effects of plan updates and amendments, as well as the effects
of specific project elements (including site plans, conditional use permits, subdivisions, and
rezoning) that have the potential to impact state facilities. Consultation between the lead
agency, WSDOT, and those preparing the TIA is essential early in the process to help determine
appropriate scenario analyses and goals. For further guidance, consult the Traffic Analysis
Procedures Manual and Development Services Manual.

Depending on the type of work being analyzed, required TIA scenarios can range from simple
“existing conditions with and without project,” to more complex analyses where TIA scenarios
could include: existing; opening year with and without project; interim years with and without
project; and design year with and without project. If developed with WSDOT, and if following
ARR guidance, pre-ARR work such as Area Study TIAs can be used in future ARRs.

The appropriate and necessary scenarios shall be agreed upon by the TIA study team and
documented in the TIA Methods and Assumptions (M&A) Document.

For existing networks, calibrate models to existing conditions.

If a near-term baseline network is required, only funding-secured projects should be added

to the existing network. This is typical of opening year models that are a few years beyond
existing year.

For interim scenario networks, include only projects or developments within the forecasting
process that have the highest probability within the 10-year horizon. For example, include
projects that are fully funded or have a construction phase in the six-year Transportation
Improvement Plan.

For scenarios with phases beyond 10 years, TIA or ARR teams should discuss and document
the merits of including other potential projects. For example:
• Projects on current long-range regional transportation plans (or the locally-adopted
transportation plan, if the TIA is not on a regionally-significant facility)
• Projects on the HSP or MTP

All other potential influences with lower probability should not be allowed to affect travel or
trip demand forecast results—with one exception: TIAs and ARRs may include multiple scenarios
for the design year. For example, if a major assumption for unfunded additional lanes “feeding
traffic into” or “allowing traffic from” the project is desired for the design year to allow for a
better understanding of expensive infrastructure sizing (such as ultimate bridge widths), ensure

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a constrained design year scenario is included so that proper funding-based phasing solutions
are communicated.

320.07 TIA Methods and Assumptions Document

The TIA M&A is similar to an ARR M&A in that it documents the “who, what, where, when, how,
and why” items associated with the traffic analysis portion of a project.

Prior to any substantial fieldwork or traffic/facility data collection, consultation between the
lead agency, WSDOT, and those preparing the TIA is encouraged to help reach and document
consensus on study data needs and assumptions. These and other items should be documented
and the M&A signed by all lead staff that conduct work in association with the TIA M&A
document. For further guidance, consult the Traffic Analysis Procedures Manual and
Development Services Manual.

320.08 TIA Methodologies

The FHWA Traffic Analysis Toolbox, Volume 2, provides a methodology for selecting traffic
analysis tools. However, in general, traffic analysis methodologies for those facility types
indicated below are used by WSDOT and will be accepted if agreed upon by those who
sign TIA or ARR M&A Documents.
• Freeway Segments: Highway Capacity Manual/Software (HCM/S); operational and
design analysis; macroscopic, mesoscopic, and microsimulation
• Weaving Areas: Design Manual (DM); HCM/S; operational and design analysis;
microsimulation
• Ramps and Ramp Terminals: HCM/S; operational and design analysis; DM;
microsimulation
• Multilane Highways: HCM/S; operational and design analysis; macroscopic,
mesoscopic, and microsimulation
• Two-Lane Highways: HCM/S; operational and design analysis
• Intersection, Signalized: Sidra; Synchro; SimTraffic; HCM/S; Vissim,
• Intersection, Roundabout: Sidra; Rodel; HCM; Vissim
• Corridors: Sidra; Synchro; SimTraffic; HCM; Vissim
• Stop-Controlled Intersections: HCM/S for capacity; DM Chapter 1330 and
the MUTCD for signal warrants (if a signal is being considered)
• Transit: HCM/S; operational and design analysis; Traffic Manual
• Pedestrians: HCM/S
• Bicycles: HCM/S
• WSDOT Criteria/Warrants: MUTCD (signals, stop signs); Traffic Manual (school
crossings); DM Chapter 1040 (freeway lighting, conventional highway lighting)
• Channelization: DM

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The procedures in the Highway Capacity Manual do not explicitly address operations of
closely spaced signalized intersections, nor does WSDOT currently endorse microsimulation
or roundabout guidance as noted in the HCM/S. Under such conditions, several unique
characteristics must be considered, including spill-back potential from the downstream
intersection to the upstream intersection; effects of downstream queues on upstream
saturation flow rates; and unusual platoon dispersion or compression between intersections.
An example of such closely spaced operations is signalized ramp terminals at urban
interchanges. Queue interactions between closely spaced intersections can seriously
distort the results of analyses that follow the procedures in the HCM.

Other analysis methods may be accepted; however, consultation between the lead agency,
region or HQ Traffic, and those preparing the TIA is encouraged to reach consensus on the
data necessary for the analysis if meso- or microsimulation is employed. When a state highway
has saturated flows, the use of a meso- or microsimulation models can provide additional
understanding. Note, however, that the simulation model must be calibrated and validated
for reliable results and is intended for near-term operational analyses (see the Traffic Analysis
Procedures Manual for guidance on calibration and validation).

Operational MOEs for simulation models based on long-term forecasts should be used primarily
to determine which scenarios are better than others. The models can only do so if the resultant
MOEs demonstrate significant differentiation between scenarios. TIA or ARR teams will
determine what is considered significant and will document those findings in the study. However,
at a minimum, significant must be greater than the expected error band of the models used. For
example, if Vissim is considered to be calibrated to a given MOE within 15% of existing conditions
(a very wide band), the scenarios need to show greater than 15% differentiation between each
other to be significant.

320.09 TIA Mitigation Measures

Consultation between the lead agency, WSDOT, and the responsible parties preparing the TIA
is recommended in order to reach consensus on the project mitigation measures. Mitigation
measures, if applicable, need to be included in the TIA to determine whether a project’s impacts
can be eliminated or reduced to a level of insignificance. Eliminating or reducing impacts to a
level of insignificance is the standard pursuant to the State Environmental Policy Act (SEPA) and
National Environmental Policy Act (NEPA). The lead agency is responsible for administering the
SEPA and/or NEPA review process. WSDOT is responsible for reviewing the TIA for impacts that
pertain to state highway facilities. However, the authority vested in the lead agency under SEPA/
NEPA does not take precedence over other authorities in law.

Development work in the state highway right of way requires a WSDOT permit or agreement.
Normally, this work is coordinated by the region Development Services Office.

Mitigation measures may take the following forms:

• Channelization such as turn lanes or raised islands
• Installation of a roundabout or, if necessary, a traffic signal (signal warrant
analysis per MUTCD is required)
• Frontage improvements
• Donation of right of way

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• Addressing any design or operational deficiencies created by the proposal

• Possible restrictions of turning movements
• Sight distance enhancements
• Traffic mitigation payment (pro rata share contribution) to a programmed
WSDOT project (see Chapter 4 of the Development Services Manual)
• Satisfaction of local agency guidelines and interlocal agreements

320.10 TIA Report

320.10(1) TIA Minimum Contents
The minimum contents of a TIA report are listed in the Traffic Analysis Procedures Manual and
Development Services Manual. Listed below is a summary; however, the depth and detail of
content under each element varies in relation to the scale and complexity of the project.

(a) Executive Summary

(b) Table of Contents

1. List of Exhibits (Maps)

2. List of Tables

(c) Introduction

1. Description of the proposed project with purpose and need.

2. Traffic Impact Analysis Methods and Assumptions summary.
3. Map of project location.
4. Site plan, including all access to state highways (site plan, map).
5. Circulation network, including all access to state highways (vicinity map).
6. Land use and zoning.
7. Phasing plan, including proposed dates of project (phase) completion.
8. Project sponsor and contact person(s).
9. References to other traffic impact studies.
10. Other mitigation measures considered

(d) Traffic Analysis

1. TIA M&A (see the Traffic Analysis Procedures Manual for a template or the Development
Services Manual).
2. Existing and projected conditions of the site: posted speed; traffic counts (to include
turning movements); sight distance; channelization; design analyses; pedestrian and
bicycle facilities; design vehicle; and traffic controls, including signal phasing and multi-
signal progression where appropriate (exhibit(s)).

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3. DHV and ADT; project trip generation and distribution map, including references and a
detailed description of the process involved in forecasting the projected trips, including
tables.
4. Project-related transportation mode split, with a detailed description of the process
involved in determining transportation mode split.
5. Project-generated trip distribution and assignment with a detailed description of the
process involved in distributing and assigning the generated traffic, including exhibit(s).
6. If intersection control additions are employed and traffic signals are assumed, include
functionality and warrant analyses. With roundabouts or signals, include existing
conditions, cumulative conditions, and full-build of plan conditions with and without
project.
7. Safety performance analysis (see Chapter 321 and the Traffic Analysis Procedures
Manual).

(e) Conclusions and Recommendations

1. Quantified or qualified LOS, QOS, and other appropriate MOEs of impacted facilities
with and without mitigation measures.
2. Predicted safety performance with and without mitigation measures.
3. Mitigation phasing plan with dates of proposed mitigation measures.
4. Defined responsibilities for implementing mitigation measures.
5. Cost estimates for mitigation measures and financing plan.

(f) Appendices

1. Description of traffic data and how data was collected and manipulated.
2. Description of methodologies and assumptions used in analyses.
3. Worksheets used in analyses; for example, signal warrants, LOS, QOS, and traffic
count information.
4. If microsimulation is used, provide a copy of the Confidence and Calibration Report.

320.11 References
320.11(1) Federal/State Laws and Codes
42 United States Code 4321, National Environmental Policy Act (NEPA) of 1969

Revised Code of Washington (RCW) 43.21C, State environmental policy (Chapter 197-11
WAC and Chapter 468-12 WAC)

RCW 36.70a, Growth Management Act

RCW 36.70A.070, Comprehensive plans – Mandatory elements

RCW 47.06.140, Transportation facilities and services of statewide significance – Level

of service standards

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Washington Administrative Code (WAC) 365-196-430, Transportation elements of

comprehensive plans

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as
adopted and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices
for streets and highways” (MUTCD)

320.11(2) Design Guidance

Design Manual, Chapter 321, for sustainable safety

Design Manual, Chapter 550, for Access Revision Report guidelines

Design Manual, Chapter 1300, for selecting intersection control type

Design Manual, Chapter 1310, for intersection guidelines

Design Manual, Chapter 1320, for roundabout guidelines

Federal-Aid Highway Program Stewardship and Oversight Agreement:

 https://www.fhwa.dot.gov/federalaid/stewardship/agreements/wa.pdf

Highway Capacity Manual (HCM), latest edition, Transportation Research Board, National
Research Council

Level of Service Standards for Washington State Highways

Roadside Design Guide and A Policy on Geometric Design of Highways and Streets, latest
editions, American Association of State Highway and Transportation Officials (AASHTO)

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01,
WSDOT

Traffic Analysis Procedures Manual (TAPM)

WSDOT Traffic Analysis web page:

 http://www.wsdot.wa.gov/design/traffic/analysis/

320.11(3) Supporting Information

Development Services Manual, M 3007.00, WSDOT

FHWA Traffic Analysis Toolbox:

 http://www.ops.fhwa.dot.gov/trafficanalysistools/index.htm

Traffic Manual, M 51-02, WSDOT

“Trip Generation,” Institute of Transportation Engineers (ITE)

WSDOT’s Highway Segment Analysis Program

WSDOT’s Planning Level Cost Estimation (PLCE) Tool

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Chapter 321 Sustainable Safety Analysis
321.01 Sustainable Safety Related Policy
321.02 HQ Safety Technical Group
321.03 Project Related Safety Analysis
321.04 Stand Alone Safety Analysis
321.05 Reports and Documentation
321.06 References

321.01 Sustainable Safety Related Policy

The Washington State Strategic Highway Safety Plan, “Target Zero” has a vision to reduce traffic
fatalities and serious injuries to zero by 2030. WSDOT is pursuing this goal along with partners
such as Washington State Patrol (WSP) and Washington Traffic Safety Commission (WTSC).
WSDOT recognizes that risk exists in all modes of transportation. The universal objective is to
reduce the number of fatal and serious injury crashes within the limits of available resources,
science, technology, and legislatively mandated priorities.

The Secretary’s Executive Order E 1085, Sustainable Highway Safety Program, sets the policy for
the Washington State Department of Transportation (WSDOT) to embark on a targeted and
scientifically-based Engineering approach for identifying and addressing crash risks that is
multimodal and coordinated with the other three “E”s, Education, Enforcement, and Emergency
Services. Sustainable Safety employs a “5th E”, Evaluation, this is the analysis and diagnosis of
crashes and to target their contributing factors in addressing highway safety performance.
Evaluation relies on quantifying safety performance using scientific tools and assessment
techniques to determine appropriate safety countermeasures.

Sustainable Safety is the approach to transportation safety at WSDOT through the use of
“…tools and procedures based on accepted science, data, and proven practice” in accordance
with Secretary’s Executive Order E 1096, Agency Emphasis and Expectations, to target safety
needs, and “deliver the right solutions at the right time and at the right location.”

Practical Solutions is an approach to making project decisions that focus on resolving the project
need for the least cost without adversely impacting safety performance. Sustainable Safety is
the approach for resolving safety performance within WSDOT’s Practical Solutions as directed in
both E 1096 and Secretary’s Executive Order E 1090, Moving Washington Forward: Practical
Solutions.

E 1085 directs engineers to base project-level decisions on safety analysis of specific locations
and corridors and focus on proven lower-cost targeted countermeasures at specific locations
that optimize the return on investment of safety dollars. These lower-cost investments allow for
additional identified locations to be addressed. Sustainable Safety is therefore an essential part
of successful Practical Design implementation. It provides the process and methods to
incorporate safety performance assessment and peer-review into Performance-Based Practical
Design. Sustainable Safety allows the planner, engineer, and decision maker, to identify and
quantify the safety performance of alternatives during project development.

Implementing Sustainable Safety improves WSDOT’s effectiveness in reducing the risk of fatal
and serious injury crashes statewide. It focuses on the contributing factors and types of crashes
through the use of state-of-the-art principles and analytical methods to diagnose, quantify, and

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Sustainable Safety Analysis Chapter 321

predict safety performance. The Sustainable Highway Safety Policy directs WSDOT to use
effective and efficient resources, like the AASHTO Highway Safety Manual (HSM) to achieve the
goals of the Washington State Strategic Highway Safety Plan: Target Zero. This approach:
1. Optimizes the reduction in fatal and serious injury crash potential on Washington’s
highways.
2. Provides quantifiable assessment of crash potential.
3. Identifies locations that have a higher potential for crash reduction.
4. Provides reliable and accurate assessment of potential crash reduction benefits.
5. Identifies and deploys solutions with optimal benefit/cost within the WSDOT safety priority
programming process or through low cost operational improvements.
6. Reduces waste by focusing on design elements that provide a reduction in crash potential.
7. Addresses locations that will result in a higher crash risk reduction potential for a given
investment level.
8. Provides an accurate assessment of project and program performance.
9. Provides scientific and engineering tools to continually improve and refine safety analyses.

Sustainable Safety is a critical, integral part of Practical Solutions that supports Washington in
reaching its Target Zero goal.

321.02 HQ Safety Technical Group

The HQ Safety Technical Group is comprised of experts in safety analysis. The team has several
duties including maintaining the Safety Analysis Guide, safety analysis training, review of
complex safety analysis, review of Crash Analysis Reports, and approve the use of crash
modification factors. The team can also provide assistance to a project office as they conduct
safety analysis.

321.03 Project Related Safety Analysis

All projects are required to have a safety analysis for Design Approval (see Chapter 300). The
safety analysis is intended to be scalable. The Safety Analysis Guide provides direction on the
scope and scale of safety analysis for each funding subprogram (i.e. I-1, I-2, P-3) and each
document needing a safety analysis (i.e. Design Analyses, Access Revision Reports (ARRs),
Intersection Control Evaluations (ICEs)). Contact the HQ Safety Technical Group if your project is
not covered by the Safety Analysis Guide or if you have questions regarding how to use the
guide.

321.04 Safety Analysis

The Safety Analysis Guide contains guidance on the content of stand-alone safety analyses for
Design Analyses, Crash Analysis Reports (CAR), ICE, Transportation Management Plans, Road
Safety Audits, Environmental Impact Statements, and ARRs. Use the procedures described in the
WSDOT Safety Analysis Guide when performing a safety analysis. Contact the HQ Safety
Technical Group if you have any questions or need to develop a stand-alone safety analysis that
is not covered in the Safety Analysis Guide.

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321.05 Reports and Documentation

The CAR, ICE, and Basis of Design (BOD) utilize safety analysis. They are described in the
following subsections. For approval requirements, refer to Chapter 300.

321.05(1) Crash Analysis Report (CAR)

A CAR is developed during the scoping phase for I-2 Crash Reduction projects and is required for
funding to be released. A template of the Crash Analysis Report with instructions is available
here: http://wwwi.wsdot.wa.gov/Planning/CPDMO/PlanningProgrammingSafety_I-2.htm

If a CAR was developed using the template for the 2019-21 biennium or newer, the project does
not need a BOD.

321.05(2) Intersection Control Evaluation (ICE)

Projects that require an ICE need to do a safety analysis on the alternatives. If a project has a
completed CAR, the ICE may reference this CAR. If not, the safety analysis for the ICE should
have a scale and scope associated with its funding source as noted in the Safety Analysis Guide.

321.05(3) Basis of Design (BOD)

The BOD utilizes metrics and targets in the baseline and contextual needs. If the chosen metric
is safety related utilize a safety analysis to determine the potential for crash reduction for
various alternatives. The safety analysis may also be used as a component in the Alternative
Comparison Table (ACT) to allow easier comparison across alternatives. The scale and scope of a
safety analysis for a BOD is associated with its program type and is explained in the Safety
Analysis Guide.

321.06 References

321.06(1) Federal/State Directives, Laws, and Codes

23 United States Code (USC) 148 – Federal requirements for the Highway Safety Improvement
Program (HSIP)

Revised Code of Washington (RCW) 47.05.010 – The statement of purpose for priority
programming of transportation projects

Secretary’s Executive Order 1085 – Sustainable Highway Safety Program

Secretary’s Executive Order 1090 – Moving Washington Forward: Practical Solutions

Secretary’s Executive Order 1096 – WSDOT 2015-17: Agency Emphasis and Expectations

321.06(2) Design Guidance

Safety Analysis Guide, WSDOT; See Sustainable Highway Safety Tools here:
 http://www.wsdot.wa.gov/Design/Support.htm

Highway Safety Manual (HSM), AASHTO, 2010

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, 2011

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321.06(3) Supporting Information

Strategic Highway Safety Plan: Target Zero – Washington State´s strategic traffic safety plan
developed by the Washington Traffic Safety Commission:  http://www.targetzero.com/

Sustainable Highway Safety Internal Web Page – Contains all of the procedures and tools to
implement highway safety:  http://wwwi.wsdot.wa.gov/HighwaySafety/

Washington Transportation Plan – Washington State Transportation Commission´s

recommended strategic transportation plan; includes a highway safety element:
 http://www.wstc.wa.gov/wtp/documents/wtp2030_201012.pdf

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Chapter 400 Surveying and Mapping
400.01 General
400.02 References
400.03 Procedures
400.04 Datums
400.05 Global Positioning System
400.06 WSDOT Survey Monument Database
400.07 Geographic Information System
400.08 Photogrammetric Surveys
400.09 Documentation

400.01 General
The Washington State Department of Transportation (WSDOT) is permitted, by an agreement
with the Board of Registration for Professional Engineers and Land Surveyors, to practice land
surveying “under the direct supervision of a licensed professional land surveyor OR a licensed
professional engineer” (see Exhibit 400-1, Interagency Agreement).

400.02 References
400.02(1) Federal/State Laws and Codes
Revised Code of Washington (RCW) 58.09, Surveys – Recording

RCW 58.20.120, System designation – Permitted uses

RCW 58.24.040(8), “ . . . temporary removal of boundary marks or monuments”

Washington Administrative Code (WAC) 332-120, Survey monuments – Removal or destruction

WAC 332-130, Minimum standards for land boundary surveys and geodetic control surveys and
guidelines for the preparation of land descriptions

Interagency Agreement Between the Washington State Department of Transportation and the
Board of Registration for Professional Engineers and Land Surveyors (1990)

400.02(2) Design Guidance

Construction Manual, M 41-01, WSDOT

Highway Surveying Manual, M 22-97, WSDOT

Plans Preparation Manual, M 22-31, WSDOT

WSDOT Survey Monument Database

 www.wsdot.wa.gov/monument/

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400.03 Procedures
For WSDOT projects, it is recommended that surveying activities include (if appropriate) but not
be limited to the following items.

400.03(1) Project Definition Phase

During the Project Definition phase, perform the following:

(a) Record any pertinent surveying information as detailed in the Design Documentation
Checklist:  www.wsdot.wa.gov/design/projectdev/
(b) Conduct research to find recorded survey monuments existing within the project area.
(c) Determine and prioritize project survey needs and tasks to be completed. Needs and tasks
may include the following issues:
• Cadastral
• Right of way
• Geodetic
• Photogrammetry
• Other issues as needed

(d) Contact city, county, state, and federal agencies, the Region Survey Office, and the
GeoMetrix Geodetic Survey section for potential impact to existing monuments.

400.03(2) Design and Development of the Plans, Specifications, and Estimates

During the design and development of the Plans, Specifications, and Estimates (PS&E), perform
the following:

(a) The project manager and project surveyor hold a preliminary survey meeting, regarding:
• Project schedule.
• Anticipated survey requests.

For preliminary survey meeting specifics and roles and responsibilities of the project
manager and project surveyor, see the Highway Surveying Manual.
(b) Perform field reconnaissance, mark existing recorded survey monuments, and determine
the location of possible new survey monuments. Also, mark found unrecorded monuments
for preservation if practical.
(c) Contact the GeoMetrix Geodetic Survey section by email, memo, or other written
notification for assistance in determining the impact to state and federal geodetic
monuments.
(d) Refer to the Highway Surveying Manual to:
• Convert Washington State Plane Coordinates to project datum.
• Document the procedure and combined factor used for converting between
datums.
• Determine survey collection methods.
• Collect primary, secondary, and tertiary survey data.
• Process and import secondary, tertiary, or other survey data into design software
for use by designers.

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(e) Apply to the Department of Natural Resources (DNR) for permits for monuments that will
be disturbed or removed (see Chapter 410).
(f) The GeoMetrix Geodetic Survey section will archive new primary survey control data in
the WSDOT Monument Database for future retrieval.
(g) Ensure that all survey monuments within the project right of way are shown on the
contract plans in order to avoid accidental damage.
(h) Develop a Record of Survey (RCW 58.09) or a Monumentation Map as required (see
Chapter 410).

400.03(3) After Construction is Completed

(a) Complete a post construction survey as described in the Highway Surveying Manual.
(b) Have the DNR Completion Report signed and stamped by the appropriate professional
in direct charge of the surveying work, then file with DNR as described in Chapter 410.

400.04 Datums
A datum is a geometrical quantity (or set of quantities) that serves as a reference, forming the
basis for computation of horizontal and vertical control surveys in which the curvature of the
earth is considered. Adjusted positions of the datum, described in terms of latitude and
longitude, may be transformed into State Plane Coordinates.

All engineering work (mapping, planning, design, right of way, and construction) for WSDOT
projects is based on a common datum.

400.04(1) Horizontal
WAC 332-130-060 states, “The datum for the horizontal control network in Washington shall be
NAD83 (1991) [the North American Datum of 1983] as officially adjusted and published by the
National Geodetic Survey of the United States Department of Commerce and as established in
accordance with Chapter 58.20 RCW. The datum adjustment shall be identified on all documents
prepared; i.e., NAD83 (1991).” (See the Highway Surveying Manual for further information.)

400.04(2) Vertical
The North American Vertical Datum of 1988 (NAVD88) as defined by the National Geodetic
Survey (NGS) is the official civilian datum for surveying and mapping activities in the United
States. WSDOT has adopted this datum. (See the Highway Surveying Manual for further
information.)

400.05 Global Positioning System

A Global Positioning System (GPS) uses a constellation of satellites and earth stationed receivers
to determine geodetic positions (latitude and longitude) on the surface of the earth. WSDOT
personnel use this survey technology. (See the Highway Surveying Manual for more detailed
discussions.)

GPS technology is changing rapidly. The key point is for the designer and surveyor to select
the best tool (GPS or conventional applications) for doing the survey fieldwork. Often, a
combination of GPS and conventional (Total Station) surveying is appropriate.

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400.06 WSDOT Survey Monument Database

The WSDOT Survey Monument Database provides storage and retrieval capabilities for data
associated with survey control monuments set by WSDOT. This database supports and tracks
the Report of Survey Mark and aids in fulfilling WSDOT’s obligation to contribute to the body
of public record, thereby minimizing the duplication of survey work. The Report of Survey Mark
provides data on specific GPS stations. (See Exhibit 400-2 for an example of a Report of Survey
Mark.)

To access the WSDOT Survey Monument Database, see the following website:
 www.wsdot.wa.gov/monument/

400.07 Geographic Information System

The Geographic Information System (GIS) is a compilation of information from many sources.
Its purpose is to assemble data into a central database for the common good. The data is stored
on many levels so the desired information can be selected and combined to achieve the desired
product. Surveying and photogrammetric data are vital elements of this system.

400.08 Photogrammetric Surveys

Photogrammetric surveys are performed to furnish topographic or planimetric maps and cross
sections for use in the reconnaissance, location, and preliminary design phases of highway work.
To use photogrammetric surveys for final design and construction requires that the ground be
nearly bare to obtain the necessary accuracy. By using well-planned aerial photography in
stereoscopic plotters, contours and other physical features are delineated on map sheets to
a scale consistent with the accuracies or detail required.

The usefulness of aerial photography is not limited to mapping. Taking the form of
enlargements, mosaics, and digital images, it can be used as a visual communication tool
(displays and exhibits) for planning, design, property acquisition, engineering, construction,
litigation, and public relations.

To obtain information on preparation, procedure, and programming of aerial photography and

photogrammetric mapping and applications, contact the HQ GeoMetrix Office. When requesting
a photogrammetric survey, specify the desired units and check the units of the product. Allow
for the time required to communicate the complex and detailed work request, develop the
service, and accomplish the product.

400.09 Documentation
For documentation related to monuments, see Chapter 410.

Primary and secondary survey control data are archived in the WSDOT Survey Monument
Database and GIS when available.

For the list of documents required to be preserved in the Design Documentation Package
and the Project File, see the Design Documentation Checklist:
 www.wsdot.wa.gov/design/projectdev/

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Exhibit 400-1 Interagency Agreement

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Exhibit 400-1 Interagency Agreement (continued)

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Exhibit 400-2 Report of Survey Mark Example

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410.01 General
410.02 References
410.03 Control Monuments
410.04 Alignment Monuments
410.05 Property Corners
410.06 Other Monuments
410.07 Filing Requirements
410.08 Documentation

410.01 General
Proper monumentation is important in referencing a highway’s alignment, which is used
to define its right of way. The Washington State Department of Transportation (WSDOT)
can contribute to the body of public records and minimize duplication of survey work by
establishing and recording monuments that are tied to a state plane coordinate system and
to a standard vertical datum. WSDOT is required by law to perpetuate existing recorded
monuments (Chapter 58.09 RCW). The department provides monuments for realignments
and new highway alignments and perpetuates existing monuments impacted by a project.
The Department of Natural Resources (DNR) is designated as the official agency for surveys
and maps. New monuments set to establish property corners, highway alignment, and so on,
shall be recorded on a Record of Survey or Monumentation Map and filed with the DNR Public
Land Survey Office and the appropriate county auditor or county engineer. Records of Survey
and Monumentation Maps are retained at DNR. Geodetic monuments are established and the
Headquarters (HQ) GeoMetrix Office retains their placement records. Geodetic monuments
are recorded on a Report of Survey Mark. These records are made available to the public on
the following website:  www.wsdot.wa.gov/monument/
Existing monuments are not to be disturbed without first obtaining the DNR permits required
by state law. DNR allows the temporary covering of a string of monuments under a single permit.
State law requires replacement of land boundary monuments after temporary removal according
to permit procedures. WSDOT control and alignment monuments may not be removed without
replacement unless the location of the original position is perpetuated by reference and the
appropriate document(s) prepared and filed with the county and the HQ Right of Way Plans
Section. Other requirements pertaining to specific monuments are discussed below.
Exhibit 410-1 summarizes the documentation requirements for new and existing monuments.
The region is responsible for identifying and locating existing monuments, obtaining required
permits before any existing monument is disturbed, and conducting the research to locate
existing monuments as required by WAC 332-120-030, as follows:
Any person, corporation, association, department, or subdivision of the state, county
or municipality responsible for an activity that may cause a survey monument to be
removed or destroyed shall be responsible for ensuring that the original survey point
is perpetuated. It shall be the responsibility of the governmental agency or others
performing construction work or other activity (including road or street resurfacing
projects) to adequately search the records and the physical area of the proposed
construction work or other activity for the purpose of locating and referencing
any known or existing survey monuments.

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410.02 References
410.02(1) Federal/State Laws and Codes
Chapter 18.43 Revised Code of Washington (RCW), Engineers and land surveyors
Chapter 58.09 RCW, Surveys – Recording
Chapter 58.24 RCW, State agency for surveys and maps – Fees
Chapter 332-120 Washington Administrative Code (WAC), Survey monuments – Removal
or destruction
Chapter 332-130 WAC, Minimum standards for land boundary surveys and geodetic control
surveys and guidelines for the preparation of land descriptions

410.02(2) Design Guidance

Electronic Engineering Data Standards
 www.wsdot.wa.gov/publications/manuals/m3028.htm
Highway Surveying Manual
 www.wsdot.wa.gov/publications/manuals/m22-97.htm
Manual of Instructions for the Survey of the Public Lands of the United States, BLM, U.S.
Department of the Interior, 1973
Plans Preparation Manual
 www.wsdot.wa.gov/publications/manuals/m22-31.htm

410.03 Control Monuments

Horizontal and vertical control monuments are permanent references required for the
establishment of project coordinates tied to the Washington State plane system and elevations
tied to a standard vertical datum. By establishing and recording permanent control monuments,
WSDOT eliminates duplication of survey work and contributes to the body of public records.
Provide the horizontal and vertical control monuments for highway projects that require the
location of existing or proposed alignment or right of way limits. Monuments set by other
agencies may be used if within 1 mile of the project and where the required datum and
accuracy were used.
When control monuments are required for a given project, show the existing and proposed
control monuments on the contract plans.
For horizontal control:
• Use North American Datum 1983, revised 1991 (NAD83/91).
• Use a minimum of second order, Class II procedures as defined in the Highway Surveying
Manual.
• Provide two monuments near the beginning of the project. Where possible, when setting
horizontal control, set points to act as azimuth points. Place points so that line of sight is
preserved between them and in an area that will not be disturbed by construction.
• Provide two monuments near the end of the project.
• Provide a pair of monuments at about 3-mile intervals throughout the length of the project.

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For vertical control:

• Use North American Vertical Datum 1988 (NAVD88). (See the Highway Surveying Manual
for orders of accuracy required.)
• Use at least second order procedures for primary vertical control within project limits as
defined in the Highway Surveying Manual. Use third order for secondary control throughout
the project.
• Provide vertical control throughout the length of the project. Desirable spacing is at or near
each milepost. Maximum spacing is 3 miles apart.
All control monuments that are established, reestablished, or reset must be filed with the county
engineer and the Department of Natural Resources (DNR). Submit a Record of Survey or a
Monumentation Map that has been signed by the supervising, licensed, professional engineer or
licensed, professional land survey. If the monument is not used to reference right of way or land
corners, submit a Report of Survey Mark. (See the Highway Surveying Manual for more detailed
guidance on Control Monuments.)

410.04 Alignment Monuments

Alignment monuments are permanent references required for the establishment or
reestablishment of the highway and its right of way. Placing monuments at random points,
in safe locations and tied to the Washington State plane coordinate system is recommended
(see the Highway Surveying Manual).
Establishment, reestablishment, or resetting of alignment monuments is required on the following
highway projects:
• New highway alignment projects.
• Highway realignment projects involving new right of way (monuments are only required
for the realigned highway section).
• Highway projects where alignment monuments already exist.
Before an existing alignment monument is reestablished or reset, a DNR permit is required.
All alignment monuments that are established, reestablished, or reset must be filed with the
appropriate county auditor or county engineer. The Record of Survey is filed with the county
auditor in the county in which the monument is located, and a recorded copy is sent to the HQ
Right of Way Plans Section. The original Monumentation Map is filed with the county engineer
of the county in which the monument is located, and a recorded copy, with the filing signatures,
is sent to the HQ Right of Way Plans Section. The HQ Right of Way Plans Section will forward
a copy to DNR for its records.

410.05 Property Corners

A new property corner monument will be provided where an existing recorded monument,
or an unrecorded monument set by a professional land surveyor (PLS) prior to the Recording
Act of 1973 (RCW 58.09), has been invalidated as a direct result of a right of way purchase by
the department. The property corner monument will be set on the new right of way line or at
a point in reference thereto. Property corner monuments may also be set at the location of new
acquisitions such as wetlands or stormwater mitigation sites or properties shown on Sundry
Site Plans. The new property corner monument shall be set by or under the direct supervision
of a licensed PLS.

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When any property corner monument is set, the licensed land surveyor shall file a Record
of Survey with the county auditor. A copy of the recorded Record of Survey is sent to the
HQ Right of Way Plans Section and HQ Real Estate Services.

410.06 Other Monuments

A DNR permit is required before any monument may be removed or destroyed.
Existing section corners and BLM or GLO monuments impacted by a project shall be reset to
perpetuate their existence. After completing the work, a DNR Land Corner Record is required.
Other permanent monuments established by any other governmental agency must not be
disturbed until the agency has been contacted to determine specific requirements for the
monument. If assistance is needed to identify a monument, contact the HQ GeoMetrix Office.
Resetting monuments must be done by or under the direct supervision of a licensed professional
engineer or a licensed professional land surveyor. If a Record of Survey is prepared, it will be
filed with the county auditor in the county in which the monument is located. If a Monumentation
Map is prepared, it is filed with the county engineer in the county in which the monument is
located, and a recorded copy is sent to the HQ Right of Way Plans Section. The HQ Right of
Way Plans Section will forward a copy to DNR for its records.

410.07 Filing Requirements

410.07(1) DNR Permit
When a DNR permit is required, use the application form shown in Exhibit 410-2. The completed
application must be signed by a licensed professional engineer or a licensed professional land
surveyor and submitted to DNR. The DNR permit applications can be downloaded in TIFF,
PDF, or Word format at the following website:
 www.dnr.wa.gov/businesspermits/howto/landownersindustrycontractors/pages/eng_plso_forms.aspx
Monumentation work cannot be done until DNR has approved the permit. In extraordinary
circumstances, verbal authorization may be granted by DNR pending the issuance of a written
permit.
After resetting the monument, the survey method used must be filed with DNR using the
completion report form shown in Exhibit 410-3. The form is to be signed by a licensed
professional engineer or a licensed professional land surveyor.

410.07(2) Monumentation Map

When a Monumentation Map is required, a plan sheet is prepared. Generally, the plan
sheet is based on a right of way plan obtained from the HQ Right of Way Plans Section.
A Monumentation Map contains a description of all new and existing monuments indicating
their kind, size, and location. In addition, it must contain the seal and signature of a licensed
professional engineer or a licensed professional land surveyor (see the Plans Preparation
Manual).
A copy of a Monumentation Map is filed with the county engineer in the county in which the
monument is located, and a recorded copy is sent to the HQ Right of Way Plans Section. The
HQ Right of Way Plans Section will forward a copy to DNR for its records.

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410.07(3) Land Corner Record

When a Land Corner Record is required, use the forms shown in Exhibit 410-4. The completed
forms are to be signed and stamped by a licensed professional engineer or a licensed professional
land surveyor and submitted to the county auditor for the county in which the monument is
located.

410.08 Documentation
Refer to Chapter 300 for design documentation requirements.

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SET NEW

WSDOT Control Monument

Before: No permit required.
After: File a copy of the Monumentation Map with the county engineer.
Send the original to the HQ Right of Way Plans Section.
Alignment Monument
Before: No permit required.
After: File a Record of Survey with the county auditor or a Monumentation
Map with the county engineer. Send a copy to the HQ Right of Way
Plans Section.
Property Corner Monument*
Before: Engage a licensed professional land surveyor.
After: Licensed professional land surveyor files Record of Survey with county
auditor, or a licensed professional engineer files a Monumentation Map
with the county engineer and sends a copy to the HQ Right of Way
Plans Section.
DISTURB EXISTING*

Control Monument
Before: Obtain DNR permit.
After: File a copy of the Monumentation Map with the county engineer.
Send the original to the HQ Right of Way Plans Section.
Alignment Monument
Before: Obtain DNR permit.
After: File a copy of the Monumentation Map with the county engineer.
Send the original to the HQ Right of Way Plans Section.
Section Corner, BLM, or GLO Monument
Before: Obtain DNR permit.
After: File Land Corner Record with the county engineer. Send a copy to the
HQ Right of Way Plans Section.
All Other Monuments
Before: Obtain DNR permit. Contact governmental agency.
After: File a copy of the Monumentation Map with the county engineer.
Send the original to the HQ Right of Way Plans Section.
* Property corner monuments must be filed within 90 days of establishment, re-establishment,
or restoration.

Monument Documentation Summary

Exhibit 410-1

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DNR Permit Application

Exhibit 410-2

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DNR Completion Report Form

Exhibit 410-3

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Land Corner Record

Exhibit 410-4

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Land Corner Record

Exhibit 410- 4 (continued)

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Chapter 510 Right of Way Considerations
510.01 General
510.02 Special Features
510.03 Easements and Permits
510.04 Programming for Funds
510.05 Appraisal and Acquisition
510.06 Transactions
510.07 Documentation
510.08 References

510.01 General
Washington State Department of Transportation (WSDOT) Real Estate Services personnel
participate in the project definition phase of a project to assist in minimizing right of way costs,
defining route locations and acquisition areas, and determining potential problems and possible
solutions.

Due to the variables in land acquisition, the categories of right of way costs considered in the
project definition phase are:
• Purchase costs (acquisition compensation).
• Relocation assistance benefits payments.
• Other Real Estate Services staff expenses (acquisition services, relocation services, and
interim property management services).

Right of way cost estimates are made by Real Estate Services specialists. When the parcels from
which additional right of way will be acquired are known, title reports (including assessors’ land
areas) can be requested.

Real Estate Services personnel also make project field inspections at appropriate times
throughout the development of a project to ensure adequate consideration is given to
significant right of way elements involved (including possible social, economic, and
environmental effects) in accordance with the Right of Way Manual.

During plan development:

• Title reports are examined for easements or other encumbrances that would reveal
the existence and location of water lines, conduits, drainage or irrigation lines, and
so on, that must be provided for in construction.
• Easements that indicate other affected ownerships are added to the right of way
and limited access plan.
• Arrangements are made to obtain utility, railroad, haul road, detour routes, or other
essential agreements, as instructed in the Utilities Manual and the Agreements
Manual.
• Right of way acquisition, disposal, and maintenance are planned.
• Easements and permits are planned (to accommodate activities outside of the right
of way).

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Engineering considerations for right of way are contained in many chapters in this manual.
Examples include chapters in the 700 series related to bridges and walls and in Chapter 1230,
Geometric Cross Section. (See Chapter 1102, Context Identification, as a recommended first
read for discussion of right of way.) Preliminary right of way widths are developed and may be
modified based on Real Estate Services’ input, but cannot be moved to coincide with property
boundaries in anticipation of a total take. Jogs in the final widths of the right of way are held to
a minimum. (See Right of Way Manual, Chapter 6, for discussion of remainders.)

All acquisition documents are processed through Headquarters (HQ) Real Estate Services except
temporary permits that are not shown on right of way plans and are not needed for the project
(such as for driveway connections).

510.02 Special Features

510.02(1) Road Approaches
On managed access highways, the department will reconstruct legally existing road approaches
that are removed or destroyed as part of the highway construction. New approaches required
by new highway construction are negotiated by the region with the approval of the Regional
Administrator. The negotiator coordinates with the region’s design section to ensure new
approaches conform to the requirements of Chapter 1340 for road approaches. All new
approaches will be by permit through the appropriate region office.

On limited access highways, road approaches of any type must be approved by the Director &
State Design Engineer, Development Division, before there is legal basis for negotiation by Real
Estate Services. When approved, approaches will be specifically reserved in the right of way
transaction and will contain the identical limitations set by the Director & State Design Engineer,
Development Division, and as shown on the approved right of way and limited access plan.

510.02(2) Cattle Passes

The desirability of or need for a cattle pass will be considered during the appraisal or negotiation
process. A cattle pass will be approved only after complete studies of location, utilization, cost,
and safety elements have proved its necessity. Upon approval, such an improvement and
appurtenant rights will be established. Future right of access for maintenance is negotiated
during acquisition.

On limited access highways, approval by the Director & State Design Engineer, Development
Division, and the addition of a traffic movement note on the right of way and limited access
plan (see the Plans Preparation Manual) are required.

510.02(3) Pit, Stockpile, and Waste Sites

These sites are investigated and planned as outlined in the Plans Preparation Manual. Detour
and haul road agreements, approved by the Regional Administrator, are necessary when the
state proposes to use city streets or county roads for the purpose of detouring traffic or hauling
certain materials. (See the Utilities Manual for detour and haul road agreement guidelines.)

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510.02(4) International Boundaries

Construction proposed “within a 20-foot strip, 10 feet on each side of the international
boundary,” must be coordinated between the department and the British Columbia Ministry
of Highways and Public Works.

Permission of the International Boundary Commission is required to work “within 10 feet of an

international boundary.” Their primary concern is monumentation of the boundary line and the
line of sight between monuments. The Commission requires a written request stating what,
when, and why construction will be done, sent to:

International Boundary Commission

United States and Canada
2000 L Street NW, Suite 615
Washington, DC 20036
( www.internationalboundarycommission.org)

510.03 Easements and Permits

510.03(1) General
If others request rights within existing WSDOT ownership, they are to contact the region Real
Estate Services Office.

Easements and permits to accommodate WSDOT activities outside the right of way usually fall
into one of the categories defined below.

Easements and permits are processed in accordance with the requirements of the Right of Way
Manual. The region Real Estate Services Office drafts the legal descriptions for all easements
and permits for acquisition of property and property rights. HQ Real Estate Services drafts the
legal description for all easements and permits for disposition of property or property rights.
The region Real Estate Services Office either obtains or assists in obtaining easements and
permits. The region is responsible for compliance with and appropriate retention of the final
documents. Records of permanent property rights acquired are maintained by HQ Real Estate
Services. Easements and permits are to be shown on the contract plans in accordance with the
Plans Preparation Manual.

510.03(2) Perpetual Easements

Perpetual easements are shown on the right of way plans in accordance with the Plans
Preparation Manual.

510.03(2)(a) State Maintenance Easement

Used when the state is to construct a facility and provide all maintenance. Examples are slope
and drainage easements.

510.03(2)(b) Dual Maintenance Easement

Used when the state is to construct and maintain a facility and the owner is to maintain the
remainder. Examples include the surface area above a tunnel and the area behind a retaining
wall or noise wall.

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510.03(2)(c) Transfer Easement

On occasion an easement must be acquired for transfer to another party. In these cases, contact
the region Real Estate Services Office for early involvement. The right of way and limited access
plan is modified to identify the party to whom the easement will be transferred. The department
cannot obtain easements for transfer across lands under the jurisdiction of the Department of
Natural Resources, and WSDOT cannot condemn for a transfer easement.

510.03(3) Temporary Easements

Temporary easements are used when the state requires a temporary property right that
involves either more than minor work or construction activities on privately owned property.
In the cases where the rights required or the work to be performed is not beneficial to the
property owner, just compensation must be paid.

When WSDOT is paying for the rights or when the encroachment is significant, temporary
easements are shown on the right of way plans, in accordance with the Plans Preparation
Manual. Consult the region Plans and Real Estate Services personnel for exceptions. If the
easement is not mapped, mark and submit plans according to the following information.

(a) The region provides a right of way plan with the required temporary easement(s) delineated
in red to the region Real Estate Services Office. These plan sheets provide:
• Ownership boundaries. Confirmation of ownership and parcel boundaries may be
completed by a search of county records and mapping; a formal title report is
required for temporary easements.
• A parcel number assigned to each ownership.
• Sufficient engineering detail to write legal descriptions.
• A statement of the intended use of each temporary easement area.

(b) In limited access areas, contact the HQ Access and Hearings Office.

510.03(4) Construction Permits

Construction permits are used for temporary rights during construction. They are not used when
WSDOT needs a perpetual right. A construction permit is only valid with the current owner and
must be renegotiated if property ownership changes before construction begins. For private
ownerships, a temporary construction easement is recommended. A construction permit is
recommended for rights of entry to publicly owned property. Local agencies might require the
use of specific forms when applying for these rights of entry. Regardless of the form or its name,
the region is responsible for appropriate central storage of the original document.

When there is a benefit to the property owner (for example, driveway or parking lot approach
improvements) the construction permit is usually obtained without the payment of
compensation (for example, donation or mutual benefits). Consult the region Plans and Real
Estate Services offices for exceptions.

510.04 Programming for Funds

For plan development, the phases in Exhibit 510-1 apply to the authorization of stage
programming.

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Chapter 510 Right of Way Considerations

When federal funds are involved, special attention must be given to Federal Highway
Administration (FHWA) requirements. When federal participation in right of way costs is
anticipated, specific authorization must be obtained from the FHWA. The rules and procedures
provided in RCW 8.26, WAC 468-100, and the Right of Way Manual must be followed to ensure
federal and state participation. In many cases, federal funds are contingent upon the department
setting up a relocation advisory procedure for any owner or tenant who is displaced by a project
and desires such assistance. Relocation advisory assistance is a function of HQ Real Estate
Services.

510.05 Appraisal and Acquisition

510.05(1) All Highways
Exhibit 510-1 shows plan development phases for both limited access highways and managed
access highways; thus, it applies to the authorization of right of way acquisition for all state
highways.

510.05(2) Exceptions
Exceptions can be made to the requirements in Exhibit 510-1 if unusual hardships result for
the individual or the state. The approval of right of way hardship action will be based on the
individual parcel merit and is processed in accordance with hardship acquisition policy (see
the Right of Way Manual).

510.06 Transactions
510.06(1) Private Ownerships
Right of way is ordinarily acquired from private property owners by region-level negotiation
between the owner and the right of way agent.

510.06(2) Utilities
The region determines the ownership of all utilities and makes arrangements for necessary
adjustment, including relocation of portions of the utility, if necessary. Provisions for relocation
or adjustment are included in the Plans, Specifications, and Estimates (PS&E) when:
• The items are normal construction items and the department is obligated for the
moving expense.
• The utility requests that relocation be performed by the department and the
department has approved the request.

Readjustment may require WSDOT to purchase substitute rights of way or easements for
eventual transfer to the utility. Such rights of way or easements must be shown on the right
of way plans with the same engineering detail as highway right of way. On limited access
highways, if an approach is required for maintenance of a utility, the approach will be shown
on the approach schedule. (See the Utilities Accommodation Policy regarding location of and
access to utilities.)

Negotiations with the utilities are often done by HQ Real Estate Services. Because of the
considerable time required to obtain approvals, processing of utility relocation agreements
must begin as soon as possible.

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510.06(3) Railways
Right of way is generally not acquired in fee from a railroad company. Instead, the state
acquires a perpetual easement for encroachment or crossing. A construction and maintenance
agreement may also be required. The easement must be shown on the right of way plan and
identified by both highway and railroad stationing.

The HQ Design Office coordinates with the railroad design staff to determine a mutually
agreeable location before the proposed easement is sent to Real Estate Services. The
negotiations with the railroads are generally done by HQ Real Estate Services. Because
of the considerable time required to obtain approvals, processing of railroad agreements
must begin as soon as possible.

The perpetual easement document is executed by the Real Estate Services Director.

510.06(4) Federal Agencies

Acquisition of right of way from most federal agencies must be negotiated and processed
through several federal offices. Allow at least one year for efficient and economical right of way
acquisition. Depending upon the particular federal agency involved, special exhibit maps and
other documentation may be required, and the right of way may be acquired as an easement
rather than in fee. The negotiations with the federal agencies are generally done by HQ Real
Estate Services.

510.06(5) Other State Agencies

Acquisition from other state agencies must be negotiated and processed through the individual
agencies or designees. Negotiations with other state agencies are generally handled by HQ Real
Estate Services. As in the case of federal agencies, substantial time must be allowed for
compliance with applicable statutes and regulations peculiar to the agency before right of way
will be granted.

510.06(6) Condemnations
Condemnation can result from a disagreement between the department and the owner
regarding a fair settlement or a faulty title. Since several months might elapse between the
filing of a condemnation case and a court decision, the region Real Estate Services Office can be
requested to investigate the possibility of obtaining a negotiated possession and use agreement
as in the case of an emergency project or when a sundry site is required immediately.

510.07 Documentation
Refer to Chapter 300 for design documentation requirements.

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Chapter 510 Right of Way Considerations

510.08 References
510.08(1) Federal/State Laws and Codes
23 Code of Federal Regulations (CFR) Part 710
49 CFR Part 24, Uniform Relocation Assistance and Real Property Acquisition for Federal and
Federally Assisted Programs
Revised Code of Washington (RCW) 8.26, Relocation assistance – Real property acquisition
policy
Washington Administrative Code (WAC) 468-100, Uniform relocation assistance and real
property acquisition

510.08(2) Design Guidance

Agreements Manual, M 22-99, WSDOT
Plans Preparation Manual, M 22-31, WSDOT
Right of Way Manual, M 26-01, WSDOT
Utilities Manual, M 22-87, WSDOT

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Right of Way Considerations Chapter 510

Exhibit 510-1 Appraisal and Acquisition

Programming of Funds for

Plan Approval Plan Approval
Appraisal and Acquisition

Limited Access Highways

Director & State Design Engineer, Development Program appraisals of total takes.
Division,* approves access report plan for (No acquisition.)
prehearing discussion with county and city officials.

PHASE 1 The access report plan may be used for preparation

Access of federal-aid program data for appraisals if federal
Report Plan funds are to be used for right of way acquisition. It
may be used for requesting advance appraisal funds
through the Planning and Capital Program
Management for all projects with either state or
federal funds.

Director & State Design Engineer, Development Program all appraisals and
Division,* approves access hearing plan for use at a acquisitions.
public access hearing. R/W information is complete.
PHASE 2 Note: Do not appraise or purchase
Access The access hearing plan may be used for the partial takes in areas subject to
Hearing Plan preparation of federal-aid program data for controversy. Appraise or purchase
negotiations on federally funded projects and for total takes only if federal design
the preparation of true cost estimates and fund hearing requirements are met.
requests.

No signature required. Program appraisals of partial takes

PHASE 3 where data is available
Findings and Results of findings and order access hearing are
to appraisers.
Order Plan marked in red and green on access hearing plan
and sent to HQ R/W Plans Section. Acquisition of total takes.

Director & State Design Engineer, Development Program all remaining appraisals
Division,* approves final R/W and L/A plans or and all remaining acquisitions.
PHASE 4 approves revisions to established R/W and L/A
Final R/W Note: If appeal period is not
plans.
and L/A Plan complete, delay action in areas
subject to controversy and possible
appeal.

Managed Access Highways

R/W plan submitted to HQ R/W Plans Section for Program appraisals.

approval.
PHASE 5
Final R/W Plan Director & State Design Engineer, Development Program all appraisals and
Division,* approves new R/W plans or approves acquisitions.
revisions to established R/W plans.

*Or a designee.

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Chapter 520 Access Control
520.01 General
520.02 References
520.03 Definitions
520.04 Vocabulary

520.01 General
The Washington State Department of Transportation (WSDOT) controls access to the state’s
highways (with a few exceptions) in order to preserve the safety and efficiency of these
highways as well as the public investment. All Washington State highways are distinguished as
being either limited access or managed access highways. Control of access is accomplished by
either acquiring rights of access from abutting property owners (limited access control) or by
regulating access connections to the highway (managed access control). Until limited access
rights have been acquired from abutting property owners, the route is a managed access
highway. Managed access permits are issued either by a local authority (city or town) or by
WSDOT.

Numerous studies have shown that controlling and limiting access to highways is a cost-effective
way to help maintain the safety, capacity, and functional integrity of a highway. Adding more
lanes to an existing highway is expensive and frequently not possible. Controlling access to our
state highways by promoting the use of frontage roads or other existing county or city roads,
and advocating the internal shared circulation within adjacent developments, is a proactive
and cost-effective way to accomplish this objective.

WSDOT has been purchasing access rights and implementing limited access control since 1951
(RCW 47.52). While this has been effective, it is an expensive way to control access to the state
highway system. Adequate funding to accomplish the purchasing of access rights has not kept
up with the state’s continual population growth and land use development over the years.
As a result, state lawmakers introduced a bill in the early 1990s recognizing that controlling
access to the state highway system by regulation was a cost-effective means to preserve the
safety and capacity of our state highway system.

In 1991, the Legislature passed and the Governor approved RCW 47.50, titled “Highway access
management.” This new law directed WSDOT to develop new rules to be included in the
Washington Administrative Code for those state highways not already limited access highways.
The result was a new class of access control called managed access.

Chapter 530 describes limited access highways in greater detail. Chapter 540 describes managed
access highways in greater detail.

The following references and definitions apply to Washington’s access control as presented in
Chapters 530 and 540.

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520.02 References
520.02(1) Federal/State Laws and Codes
Revised Code of Washington (RCW) 18.43, Engineers and land surveyors
RCW 35.78, Streets – Classification and design standards
RCW 46.61, Rules of the road
RCW 47.17, State highway routes
RCW 47.24, City streets as part of state highways
RCW 47.32, Obstructions on right-of-way
RCW 47.50, Highway access management
RCW 47.52, Limited access facilities
Washington Administrative Code (WAC) 468-51, Highway access management access permits –
Administrative process
WAC 468-52, Highway access management – Access control classification system and standards
WAC 468-54, Limited access hearings
WAC 468-58, Limited access highways

520.02(2) Design Guidance

Agreements Manual, M 22-99, WSDOT
Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on Uniform Traffic Control Devices for Streets
and Highways” (MUTCD)
Plans Preparation Manual, M 22-31, WSDOT
Right of Way Manual, M 26-01, WSDOT
Utilities Accommodation Policy, M 22-86, WSDOT
WSDOT Headquarters (HQ) Access and Hearings Section’s Internet page:
 www.wsdot.wa.gov/design/accessandhearings

520.02(3) Supporting Information

Access Management Manual, Transportation Research Board (TRB), Washington DC, 2003
Highways Over National Forest Lands, MOU between WSDOT and USFS, M 22-50, 2002:
 www.wsdot.wa.gov/publications/manuals/m22-50.htm

520.03 Definitions
access A means of entering or leaving a public road, street, or highway with respect to
abutting property or another public road, street, or highway.

access control The limiting and regulating of public and private access to Washington State’s
highways, as required by state law.

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Access Control Tracking System Limited Access and Managed Access Master Plan A database
list, related to highway route numbers and mileposts, that identifies either the level of limited
access or the class of managed access:  www.wsdot.wa.gov/design/accessandhearings

access connection See approach and access connection.

access connection permit A written authorization issued by the permitting authority for a
specifically designed access connection to a managed access highway at a specific location; for
a specific type and intensity of property use; and for a specific volume of traffic for the access
connection based on the final stage of the development of the applicant’s property. The actual
form used for this authorization is determined by the permitting authority.

access design analysis A design analysis (see Chapter 300) that authorizes deferring or staging
acquisition of limited access control, falling short of a 300-foot requirement, or allowing an
existing access point to stay within 130 feet of an intersection on a limited access highway.
Approval by the Director & State Design Engineer, Development Division, is required (see
Chapter 530).

access hearing plan A limited access plan prepared for presentation at an access hearing.

access point Any point that allows private or public entrance to or exit from the traveled way
of a state highway, including “locked gate” access and maintenance access points.

access point spacing On a managed access highway, the distance between two adjacent
access points on one side of the highway, measured along the edge of the traveled way from
one access point to the next (see also corner clearance).

access report plan A limited access plan prepared for presentation to local governmental
officials at preliminary meetings before preparation of the access hearing plan.

access rights Property rights that allow an abutting property owner to enter and leave the
public roadway system.

allowed Authorized.

application for an access connection An application provided by the permitting authority

to be completed by the applicant for access to a managed access highway.

approach and access connection These terms are listed under the specific access section
to which they apply. The first section below is for limited access highways and uses the term
approach. The second section below is for managed access highways and uses the term access
connection. Approaches and access connections include any ability to leave or enter a highway
right of way other than at an intersection with another road or street.

(a) limited access highways: approach An access point, other than a public road/street, that
allows access to or from a limited access highway on the state highway system. There are
five types of approaches to limited access highways that are allowed:
• Type A An off and on approach in a legal manner, not to exceed 30 feet in width,
for the sole purpose of serving a single-family residence. It may be reserved by the
abutting owner for specified use at a point satisfactory to the state at or between
designated highway stations. This approach type is allowed on partial and modified
control limited access highways.

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• Type B An off and on approach in a legal manner, not to exceed 50 feet in width,
for use necessary to the normal operation of a farm, but not for retail marketing. It
may be reserved by the abutting owner for specified use at a point satisfactory to
the state at or between designated highway stations. This approach type is allowed
on partial and modified control limited access highways. This approach type may
be used for wind farms when use of the approach is limited to those vehicles
necessary to construct and maintain the farm for use in harvesting wind energy.
• Type C An off and on approach in a legal manner, for a special purpose and width
to be agreed upon. It may be specified at a point satisfactory to the state at or
between designated highway stations. This approach type is allowed on partial
and modified control limited access highways and on full control limited access
highways where no other reasonable means of access exists, as solely determined
by the department.
• Type D An off and on approach in a legal manner, not to exceed 50 feet in width,
for use necessary to the normal operation of a commercial establishment. It may
be specified at a point satisfactory to the state at or between designated highway
stations. This approach type is allowed only on modified control limited access
highways.
• Type E This type is no longer allowed to be constructed because of the
requirements that there be only one access point per parcel on a limited access
state highway.
• Type F An off and on approach in a legal manner, not to exceed 30 feet in width,
for the sole purpose of serving a wireless communication site. It may be specified
at a point satisfactory to the state at or between designated highway stations. This
approach type is allowed only on partial control limited access highways. (See
WAC 468-58-080(vi) for further restrictions.)

(b) managed access highways: access connection An access point, other than a public road/
street, that permits access to or from a managed access highway on the state highway
system. There are five types of access connection permits:
• conforming access connection A connection to a managed access highway that
meets current WAC and WSDOT location, spacing, and design criteria.
• grandfathered access connection Any connection to the state highway system
that was in existence and in active use on July 1, 1990, and has not had a significant
change in use.
• joint-use access connection A single connection to a managed access highway
that serves two or more properties.
• nonconforming access connection A connection to a managed access highway
that does not meet current WSDOT location, spacing, or design criteria, pending
availability of a future conforming access connection.
• variance access connection A connection to a managed access highway at
a location not normally allowed by current WSDOT criteria.

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(c) managed access connection category There are four access connection permit categories
for managed access connections to state highways: Category I, Category II, Category III, and
Category IV (see Chapter 540).

annual daily traffic (ADT) The volume of traffic passing a point or segment of a highway,
in both directions, during a period of time, divided by the number of days in the period, and
factored to represent an estimate of traffic volume for an average day of the year.

average annual daily traffic (AADT) The average volume of traffic passing a point or segment
of a highway, in both directions, during a year.

average weekday vehicle trip ends (AWDVTE) The estimated total of all trips entering plus all
trips leaving the applicant’s site based on the final stage of proposed development.

connection See approach and access connection.

contiguous parcels Two or more pieces of real property, under the same ownership, with one
or more boundaries that touch and have similarity of use.

corner clearance On a managed access highway, the distance from an intersection of a

public road or street to the nearest access connection along the same side of the highway.
The minimum corner clearance distance (see Chapter 540, Exhibit 540-2 ) is measured from
the closest edge of the intersecting road or street to the closest edge of the traveled way of
the access connection, measured along one side of the traveled way (through lanes) (see also
access point spacing).

DHV Design hourly volume.

E&EP WSDOT’s Environmental and Engineering Programs Division.

easement A documented right, as a right of way, to use the property of another for designated
purposes.

findings and order (F&O) A legal package containing information based on the hearing record
from a limited access hearing (see Chapters 210 and 530).

findings and order (F&O) plan A limited access plan, prepared after a limited access hearing,
which is based on the hearing record.

HQ WSDOT’s Headquarters in Olympia.

intersection An at-grade access point connecting a state highway with a road or street duly
established as a public road or public street by the local governmental entity.

limited access Full, partial, or modified access control is planned and established for each
corridor and then acquired as the right to limit access to each individual parcel.
• planned limited access control Limited access control is planned for some time in the
future; however, no access hearing has been held.
• established limited access control An access hearing has been held and the Assistant
Secretary, Environmental and Engineering & Regional Operations Programs Director,
has adopted the findings and order, which establishes the limits and level of control.
• acquired limited access control Access rights have been purchased.

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Access Control Chapter 520

limited access highway All highways listed as “Established L/A” on the Limited Access and
Managed Access Master Plan (see below) and where the rights of direct access to or from
abutting lands have been acquired from the abutting landowners.
• full access control This most restrictive level of limited access provides access, using
interchanges, for selected public roads/streets only, and prohibits highway
intersections at grade.
• partial access control The second most restrictive level of limited access. At grade
intersections with selected public roads are allowed, and there may be some crossings
and some driveway approaches at grade. Direct commercial access is not allowed.
• modified access control The least restrictive level of limited access. Characteristics
are the same as for partial access control except that direct commercial access is
allowed.

Limited Access and Managed Access Master Plan A map of Washington State that shows
established and planned limited access highways:
 www.wsdot.wa.gov/design/accessandhearings

managed access highway Any highway not listed as “Established L/A” on the Limited Access
and Managed Access Master Plan and any highway or portion of a highway designated on
the plan as “Established L/A” until such time as the limited access rights are acquired. Under
managed access legislation, the property owner’s access rights are regulated through an
access connection permitting process.

median The portion of a divided highway separating vehicular traffic traveling in opposite
directions.

median opening An opening in a continuous median for the specific purpose of allowing
vehicle movement.

MOU Memorandum of Understanding. There is one MOU (Highways Over National Forest
Lands) between the United States Forest Service (USFS) and WSDOT that requires the USFS to
obtain a road approach permit for new access to a state highway that is crossing Forest Service
land.

permit holder The abutting property owner or other legally authorized person to whom an
access connection permit is issued by the permitting authority.

permitted access connection A connection for which an access connection permit has been
issued by a permitting authority.

permitting authority The agency that has legal authority to issue managed access connection
permits. For access connections in unincorporated areas, the permitting authority is WSDOT;
for access connections within corporate limits, the permitting authority is a city or town.

right of way (R/W) A general term denoting land or interest therein, acquired for or
designated for transportation purposes. More specifically, lands that have been dedicated for
public transportation purposes or land in which WSDOT, a county, or a municipality owns the
fee simple title, has an easement devoted to or required for use as a public road/street and
appurtenant facilities, or has established ownership by prescriptive right.

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right of way and limited access plan (R/W and L/A plan) A right of way plan that also shows
limited access control details.

road approach A road or driveway built to provide private access to or from the state highway
system.

shoulder The portion of the highway contiguous with the traveled lanes for the
accommodation of stopped vehicles for emergency use and, where allowed, for bicycles
(see Chapter 530).

state highway system All roads, streets, and highways designated as state routes in
compliance with RCW 47.17.

520.04 Vocabulary
The entries shown in Exhibit 520-1 are examples of suitable wording for the distinctly different
types of access control in Chapters 530 and 540.

These entries demonstrate the difference in terminology between limited access and managed
access in the applicable WACs. For instance, there is nothing about permit, connection, category,
or class in the limited access vocabulary and, likewise, nothing about approach or type in the
managed access vocabulary.

Also note that Chapter 1340 uses road approach, access, and driveway in a generic way,
unrelated to WAC legal terminology, and makes no distinction related to access control.

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Access Control Chapter 520

Exhibit 520-1 Access Control Vocabulary

Access Control Vocabulary

intersections at grade, geometrics Chapter 1310
roundabout geometrics Chapter 1320
road approach geometrics Chapter 1340
interchange geometrics Chapter 1360
freeway access point Chapter 550
functional classification of highways WSDOT Functional Classification web site:
 http://www.wsdot.wa.gov/mapsdata/travel/hpms/
functionalclass.htm
Limited Access Highway (Chapter 530) Managed Access Highway (Chapter 540)

Access point (freeway ramp or other access break) Access point (public or not)
Approach (street, road, driveway) • Public access point
• Road approach (street, road, driveway) • Access connection (not public)
• Driveway approach (not street or road)
(Level of) limited access (highway) Managed access highway class
• Full/partial/modified control limited • Class (1-5) managed access highway
access highway

Type (A, B, C, D, F) approach Category (I-IV) access connection

Type A approach = Type A road approach

Allowed (policy) Permitted (a document) or allowed (policy)

Conforming access connection permit

(among others)

Terms Not Used in Chapter 530 Terms Not Used in Chapter 540

class classification (except functional)

category type

connection approach

permit or permitted

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Chapter 530 Limited Access Control
530.01 General
530.02 Achieving Limited Access
530.03 Full Control (Most Restrictive)
530.04 Partial Control
530.05 Modified Control (Least Restrictive)
530.06 Access Approaches
530.07 Frontage Roads
530.08 Turnbacks
530.09 Adjacent Railroads
530.10 Access Breaks and Inner Corridor Access
530.11 Documentation

530.01 General
Limited access control is established to preserve the safety performance and efficiency of
specific highways for all modes and to preserve the public investment. Limited access control is
achieved by acquiring access rights from abutting property owners and by selectively limiting
approaches to a highway, considering all modes in the control and treatment of access. (For an
overview of access control and the references list and definitions of terminology for this
chapter, see Chapter 520, Access Control.)

Requirements for the establishment of limited access highways are set forth in the Revised Code
of Washington (RCW) 47.52. The type of access control applied to a location is considered a
design control (see Chapter 1103), and is determined during planning, scoping, or the early
stages of design in conformance with this chapter.

Highways controlled by acquiring abutting property owners’ access rights are termed limited
access highways and are further distinguished as having full, partial, or modified control. The
number of access points per mile, the spacing of interchanges or intersections, and the location
of frontage roads or local road/street/trail approaches are determined by the:
 Functional classification and importance of the highway
 Context-based modal priorities and relevant considerations
 Character of the traffic
 Current adjacent land use and future planned changes to land use
 Environment and aesthetics
 Highway design, operation, safety and connectivity for all modes
 Economic considerations involved

The Federal Highway Administration (FHWA) has jurisdiction on the Interstate System. The
Washington State Department of Transportation (WSDOT) has full jurisdiction on all other
limited access highways, whether they are inside or outside incorporated city limits.

WSDOT maintains a record of the status of limited access control, by state route number and
milepost, in the Access Control Tracking System Limited Access and Managed Access Master
Plan database (Access Master Plan). See the Access and Hearings website:
http://www.wsdot.wa.gov/Design/accessandhearings/

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Limited Access Control Chapter 530

530.02 Achieving Limited Access

530.02(1) Evaluation
The benefits of maintaining or acquiring full, partial, or modified control are to be evaluated
during project development if the route is shown in the Access Control Tracking System Limited
Access and Managed Access Master Plan database as either “established” or “planned” for
limited access. It is generally known that full limited access control applies to interstates and
freeways. However, state highways that do not fall under full access control may have more
flexibility in the type of control applied (whether limited or managed control). These highways
can benefit by having access control evaluations conducted early in planning and project
development.

The cost of acquiring limited access is evaluated to determine whether those costs will be
included in the project. The evaluation includes the societal costs of crashes, current and future
land use development, and the improved level of service for motor vehicle traffic of limited
access highways. Use the Basis of Design documentation tool to summarize key results of the
evaluation process, considering connectivity, mobility, safety and accessibility for all modes.
(See chapters in the 1100 series for more information on using the Basis of Design tool.)

530.02(2) Process
All Washington State highways are managed access highways (see Chapter 540), except where
limited access rights have been acquired. The right of way and limited access plans for routes
show the acquired limited access boundaries. This is further represented in the Access Control
Tracking System, a database that identifies the status and type of access control for all state
highways. The database lists the specific types of limited access control (full, partial, or
modified) and identifies whether the control is planned, established, or acquired for a specific
route segment. If limited access has not been acquired, the database reports the type of
managed access classification that currently applies.

The existing access classification is periodically updated to reflect changes on a corridor

segment. The planned limited access reflects the vision for access on a corridor by resolution
from the Washington Transportation Commission in the 1960s and 1970s. Conditions may have
changed since the plan for limited access was envisioned. It is important to re-evaluate this plan
and determine the access design control most appropriate for the agreed context. (See
Chapters 1102 and 1103 for context and design control guidance, respectively.) For help
determining the status of limited access control for any state highway, consult the Headquarters
(HQ) Access and Hearings Section.

The Access Master Plan database is available at:

www.wsdot.wa.gov/design/accessandhearings

530.02(2)(a) Procedure for Limited Access Control

Use the following procedure to achieve limited access control:

1. The Secretary of Transportation (or a designee) first identifies a highway as “Planned for
Limited Access.”
2. To establish or revise limited access on a new or existing highway, either a limited access
hearing is held or waivers are obtained. (See Chapter 210, Public Involvement and Hearings,

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regarding hearings, and Chapter 510, Right of Way, for the phases of appraisal and
acquisition.)

a. Phase 1
The region develops a limited access report and a limited access report plan for department
approval and presentation to local officials. The plan notes the level of limited access
proposed to be established.

b. Phase 2
The region develops a limited access hearing plan for Director & State Design Engineer,
Development Division (or designee), approval and for presentation at the hearing.

c. Phase 3
After the hearing, the region develops the findings and order and revises the limited access
hearing plan to become the findings and order plan (see Chapter 210). The findings and
order is processed and sent to the HQ Access and Hearings Section for review and approval.
The Assistant Secretary, Regions and Mega Programs/Chief Engineer, adopts the findings
and order and thus establishes the limits and level of limited access control to be acquired.

d. Phase 4
The findings and order plan is now revised by the HQ Right of Way Plans Section for
approval by the Director & State Design Engineer, Development Division (or designee), as a
Phase 4 final right of way and limited access plan.
3. Real Estate Services acquires limited access rights from individual property owners based on
final design decisions and updates the right of way and limited access plans and the
property deed.
4. These highways or portions thereof are now limited access highways and no longer fall
under the managed access program.

530.02(3) Access Report (RCW 47.52.131)

The Access Report is developed by the region to legally inform local governmental officials of
the proposed limited access highway and the principal access features involved, and to secure
their approval. This report is not furnished to abutting property owners. Submit the report to
the HQ Access and Hearings Section for review and approval prior to submission to local
authorities. Including local agencies as stakeholders from the onset of the project helps establish
project expectations and positive working relationships, making reviews and approvals run as
smoothly as possible.

530.02(3)(a) Access Report Content

The Access Report consists of the following:

1. A description of the existing and proposed highways, including data on the history of the
existing highway, which may include references to safety analyses and also locations
identified in WSDOT’s priority programming process.
2. Traffic analyses pertaining to the proposed highway, including available information about
current and potential future motor vehicle, pedestrian, bicyclist, transit, and freight traffic
volumes on county roads and city streets crossing or severed by the proposed highway and
reference sources such as origin-destination surveys.

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Limited Access Control Chapter 530

Traffic data, together with counts of existing traffic available from state or local records, is
normally adequate for motor vehicle analysis. Special counts of existing traffic are obtained
only if circumstances indicate that the available data is inadequate or outdated. Data for
pedestrian and bicyclist traffic may rely on demographics, land-use context, and an analysis
of the active transportation network where volume information is not available.

3. A discussion of factors affecting the design of the subject highway, including:

 Functional classification
www.wsdot.wa.gov/mapsdata/travel/hpms/functionalclass.htm
 Level and limits of limited access control.
 Roadway section.
 Interchange, grade separation, and intersection spacing.
 Modal Priority determinations or Final Modal Accommodation Level and Land Use
Context assessment (documented on the Context and Modal Accommodation
Report)
 Travel markets and demographics, including special needs and vulnerable
populations.
 Existing and future planned pedestrian and bicycle trails or shared-use paths.
 Existing and future planned transit service on or adjacent to the section.
 Motor vehicle operational controls with emphasis on proposed fencing, the general
concept of illumination, signing, and other traffic control devices, and an indication of
how the operational controls will maintain or enhance connectivity for pedestrians
and bicyclists.
 Location of utilities and how they are affected.
 Proposed plan for landscaping and beautification, including an artist’s graphic
rendition or design visualization.
4. Governmental responsibility, and comprehensive planning, land use, and community service
relative to the new highway.
5. The disposition of frontage roads, city street and county road intersections, and excess right
of way.
6. An appendix containing:
 A glossary of engineering terms.
 A traffic volume diagram(s) for all modes.
 Pages showing diagrammatically or graphically the roadway section(s), operational
controls, and rest areas (if rest areas are included in the project covered by the
report) for all modes.
 A vicinity map.
 An access report plan and profiles for the project.
 Basis of Design

The limited access report plan shows the effects of the proposed highway on the street and
road system, transit service and pedestrian/bicyclist network by delineating the points of
public access. (See the Plans Preparation Manual for a list of the minimum details to be
shown on the plan and for a sample plan.)

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7. Notifications and reviews. Upon receipt of the Phase 1 approval (see Exhibit 510-1) from the
Director & State Design Engineer, Development Division, the region publishes the necessary
copies, submits the limited access report to the county or city officials for review and
approval, and meets with all involved local governmental agencies to discuss the report.
Providing a form letter with a signature block for the local agency to use to indicate its
approval of the limited access report can help expedite the review and approval process.

The region reviews any requests for modification and submits recommendations, with copies
of any correspondence or related minutes, to the HQ Access and Hearings Section.

530.02(4) Limited Access Hearing Plan

The region prepares a limited access hearing plan to be used as an exhibit at the public hearing
(see Chapter 210 for hearings) and forwards it to the HQ Right of Way Plans Section for review.
(See the Plans Preparation Manual for a list of data to be shown on the access hearing plan in
addition to the access report plan data.)

When the plan review is completed by Headquarters, the access hearing plan is placed before
the Director & State Design Engineer, Development Division, for approval of Phase 2 authority
(see Exhibit 510-1).

530.02(5) Documentation
Documentation for the establishment of limited access control is in Chapter 210.

530.03 Full Control (Most Restrictive)

530.03(1) Introduction
Full control limited access highways allow access only through interchanges at selected public
roads/streets, rest areas, viewpoints, or weigh stations, and by prohibiting at-grade crossings
and approaches.

At times, on state highways (except interstate) where full access control has been established,
staged acquisition of limited access may be used, subject to the approval of an access design
analysis, with initial acquisition as partial or modified control and with ultimate acquisition of
full control planned on the highway. When there is no feasible alternative within a reasonable
cost, the decision to defer acquisition of limited access control must be documented and is
subject to the approval of an access design analysis.

530.03(2) Application
Terminate full control limited access sections at apparent logical points of design change. The
following guidelines are to be used for the application of full control on limited access highways.

530.03(2)(a) Interstate

Full control is required on interstate highways.

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530.03(2)(b) Principal Arterial

Documentation assessing the evaluation of full control is required for principal arterial highways
requiring four or more through traffic lanes within a 20-year design period unless approved for
partial or modified control on existing highways.
530.03(2)(c) Minor Arterial and Collector

Minor arterial and collector highways will not normally be considered for development to full
control. However, short sections of full control to preserve the operational and safety
performance of all modes may be appropriate in some situations.

530.03(3) Crossroads at Interchange Ramps

At interchanges where ramps terminate with crossroads, limited access control will extend along
crossroads, and in certain cases along local service or frontage roads (as shown in Exhibits
530-1a through 530-1f). This establishes the Interchange Functional Area, for the preservation
of operational and safety performance of the interchange asset. For guidance on interchange
spacing, see Chapter 1360.

530.03(3)(a) Ramps

At-grade intersections and approaches are prohibited within the full length of any interchange
ramp. The ramp is considered to terminate at its intersection with the local road or street.
530.03(3)(b) Frontage Roads

Direct access from the highway to a local service or frontage road is allowed only via the
interchange crossroad (see Exhibits 530-1a, 1b, 1c, and 1f).
530.03(3)(c) Interchange Crossroads

In both urban and rural areas, full control limited access must be established and then acquired
along the crossroad at an interchange for a minimum distance of 300 feet. This distance is
measured from the centerline of the intersection of the crossroad and ramp terminal unless
noted otherwise in the conditions below. Control designs in all crossroad contexts should
address and incorporate connectivity for shared-use paths, trails and sidewalks in and beyond
the control area.

If a frontage road or local road is located at or within 350 feet of a ramp terminal, limited access
will be established and then acquired up to the intersection, then along the crossroad and for an
additional minimum distance of 130 feet in all directions from the centerline of the intersection
of the crossroad and the frontage or local road, or measured from the outside edge of the
outermost circulating roadway for roundabouts (see Exhibits 530-1a, 1b, 1c, and 1f).

For interchanges incorporating partial cloverleaf or buttonhook ramps (see Exhibit 530-1b),
limited access is required for all portions of the crossroad and frontage roads between the ramp
terminals and for a distance of 300 feet beyond the ramp terminals. If an at-grade intersection
for a local road or street is served directly opposite the ramp terminals, limited access will be
extended for a minimum of 300 feet along that leg of the intersection.

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When the intersection in question is a roundabout, see Exhibit 530-1c. This shows extension of
full control along the crossroad to be 300 feet, measured from the center of the roundabout for
an intersection with a ramp terminal.

Exhibit 530-1d shows the terminus of transition taper and that full control limited access is
extended a minimum distance of 300 feet beyond the end of the farthest taper.

For a single point urban interchange (SPUI) with a right- or left-turn “ramp branch” separated by
islands, limited access control is established and acquired for a minimum distance of 300 feet
from the intersection of the centerline of the ramp branch with the centerline of the nearest
directional roadway (see Exhibit 530-1e.)

For a diverging diamond interchange, limited access control is established and acquired for a
minimum distance of 300 feet from the end of the splitter island nose (see Exhibit 530-1f).

Not all interchange configurations match with the basic illustrations in this chapter. Consult with
the HQ Access and Hearings Section for confirmation of limited access boundary requirements
for non-traditional interchange configurations.

530.03(3)(d) Levels of Limited Access: Location of Approaches

Provide full control for a minimum of 300 feet from the centerline of the ramp or terminus of a
transition taper (see Exhibits 530-1a through 530-1f). The intent is to ensure approaches are far
enough away from a frontage road intersection to provide efficient intersection operation.

If the economic considerations to implement full control for the entire 300 feet are excessive,
then provide full control for at least the first 130 feet; partial or modified control may be
provided for the remainder, for a total minimum distance of 300 feet of limited access. Full
limited access should be extended as far as possible before any partial or modified access is
implemented. Contact the HQ Access and Hearings Section when considering this option.

An approved access design analysis is required if the limited access control falls short of 300 feet
or for any approach that has been allowed to remain within the first 130 feet.

530.03(4) Location of Utilities, Bus Stops, and Mailboxes

530.03(4)(a) Utilities

Connecting utility lines are allowed along the outer right of way line between intermittent
frontage roads. (See the Utilities Accommodation Policy regarding the location of and access to
utilities.)
530.03(4)(b) Bus Stops

Common carrier or school bus stops are not allowed, except at:
 Railroad crossings (see Chapter 1350).
 Locations provided by the state on the interchanges (such as flyer stops).
 In exceptional cases, along the main roadway where pedestrian separation is available.

530.03(4)(c) Mailboxes

Mailboxes are not allowed on full control limited access highways. Mail delivery will be from
frontage roads or other adjacent local roads.

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530.03(5) Pedestrian and Bicyclist Crossings and Paths

All pedestrian and bicyclist traffic is managed as follows:
 At-grade pedestrian and bicyclist crossings are allowed only at the at-grade
intersections of ramp terminals.
 Pedestrian and bicyclist separations or other facilities are provided specifically for
pedestrian and bicyclist use.
 Shared-use paths serving bicyclists, pedestrians, and other forms of active
transportation. See Chapter 1515.
 Bicyclists use the right-hand shoulders or other facilities as shown in Chapter 1520,
except where such use has been specifically prohibited. Information pertaining to such
prohibition is available from the WSDOT website:
http://wsdot.wa.gov/bike/closed.htm

Paths and trails, and access to and from, within a limited access highway are best planned and
designed with the local agency’s participation. Pedestrians and bicyclists are allowed, consistent
with “Rules of the Road” (RCW 46.61), within the limits of full control limited access highways.
Where existing or future planned paths are allowed they must be documented on the right of
way and limited access plan. The plan shows the location of the existing or proposed path and
where the path crosses limited access and provides movement notes (see 530.10(1)). See
Chapter 1515 for shared-use path design guidance.

530.04 Partial Control

530.04(1) Introduction
Partial control may be established, when justified, on any highway except interstate. Partial
control provides a considerable level of protection from motor vehicle traffic interference and
protects the highway from future strip-type development while maintaining and improving
appropriate active transportation network connections.

Upon acquisition of partial control limited access rights, the number, type, and use of access
approaches of abutting property are frozen. The abutting property access rights and type of use
are recorded on the property deed. The rights and use may not be altered by the abutting
property owner, the local jurisdiction, or the region. This authority resides with the Director &
State Design Engineer, Development Division (see 530.10).

530.04(2) Application
Partial control will not normally be used in urban areas, urbanizing area, suburban area, rural
town centers or inside corporate limits on existing principal arterial highways where motor
vehicle traffic volumes are less than 700 design hourly volume (DHV).

Terminate limited access sections at apparent logical points of design change.

530.04(2)(a) Principal Arterial

Partial control is considered when the estimated motor vehicle traffic volumes exceed 3,000
average daily traffic (ADT) within a 20-year design period on principal arterial highways requiring

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two through motor vehicle traffic lanes. For multilane principal arterial highways, see
530.03(2)(b).
530.04(2)(b) Minor Arterial

The minimum route length is: urban, 2 miles; rural, 5 miles; and combination urban and rural, 3
miles.

Partial control is required on:

 Rural minor arterial highways at both new and existing locations.
 Urban minor arterial highways at new locations requiring four or more through motor
vehicle traffic lanes within a 20-year design period or requiring only two through motor
vehicle traffic lanes where the estimated motor vehicle traffic volumes exceed 3,000
ADT within a 20-year design period.

Other rural minor arterial highways with only two motor vehicle lanes may be considered for
partial control if any of the following conditions applies:
 The partial control can be acquired at a reasonable cost.
 The route connects two highways of a higher functional classification.
 The highway traverses publicly owned lands where partial control is desirable.
530.04(2)(c) Collector: New Alignment

Partial control is considered on collector highways in new locations requiring four or more
through motor vehicle traffic lanes in a 20-year design period

530.04(2)(d) Collector: Existing

Existing collector highways will normally be considered for partial control limited access only
when all of the following conditions apply:
 The highway serves an area that is not directly served by a higher functional
classification of highway.
 Existing or planned development will result in motor vehicle traffic volumes
significantly higher than what is required for partial control on minor arterials.
 Partial control can be established without a major impact on development of abutting
properties within the constraints of established zoning at the time the partial control is
proposed.

530.04(3) Interchanges and Intersections

530.04(3)(a) Interchanges

Where an interchange occurs on a partial control limited access highway, full control applies at
the interchange and interchange ramps. Refer to 530.03(3) and see Exhibits 530-1a, 1b, 1c, and
1f for required minimum lengths of access control along the crossroad. For these and other
interchange configurations not shown, consult with the HQ Access and Hearings Section for
support developing limits of access control. (See Chapter 1360 for guidance on interchange

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spacing.) Where appropriate, address and incorporate connectivity for shared-use paths, trails
and sidewalks in and beyond the control area.
530.04(3)(b) Intersections

At an at-grade intersection on a partial control limited access highway, control will be

established and acquired along the crossroad for a minimum distance of 300 feet from the
centerline of the highway (see Exhibit 530-2a). Where appropriate, address and incorporate
connectivity for shared-use paths, trails and sidewalks in and beyond the control area.

If another frontage or local road is located at or within 350 feet of the at-grade intersection,
limited access will be established and then acquired along the crossroad, between the
intersections, and:
 For an additional minimum distance of 130 feet in all directions from the centerline of
the intersection of the frontage or local road (see Exhibit 530-2a).
 In the case of a roundabout, for an additional minimum distance of 300 feet along the
crossroad, measured from the center of the roundabout (as shown in Exhibit 530-2b).

On multilane highways, measurements will be made from the centerline of the nearest
directional roadway (see Exhibit 530-2a).

An approved access design analysis is required if the limited access control falls short of 300 feet
or for any access that has been allowed to remain within the first 130 feet.

At-grade intersections with public roads are limited to the number allowed for the functional
classification of highway involved, as follows:
530.04(3)(b)(1) Principal Arterial

If the ADT of the crossroad is less than 2,000, 1-mile spacing (minimum), centerline to
centerline. If over 2,000 ADT within 20 years, plan for grade separation.

530.04(3)(b)(2) Minor Arterial

If the ADT of the crossroad is less than 2,000, ½-mile spacing (minimum), centerline to
centerline. If over 2,000 ADT within 20 years, plan for grade separation.

530.04(3)(b)(3) Collector

Road (or street) plus property approaches, not more than six per side per mile.

With approval from the Director & State Design Engineer, Development Division, shorter
intervals may be used where topography or other conditions (such as parcel sizes in some
cases) restrict the design. Where intersecting roads are spaced farther apart than one per
mile, median crossings may be considered for U-turns, in accordance with Chapter 1310.
Keep U-turns to a minimum, consistent with requirements for operation and maintenance
of the highway.

To discourage movement in the wrong direction on multilane highways, locate private

approaches 300 feet or more from an at-grade intersection. At a tee intersection, a private
approach may be located directly opposite the intersection or a minimum of 300 feet away

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from the intersection. Ensure a private approach directly opposite a tee intersection cannot
be mistaken for a continuation or part of the public traveled way.

530.04(4) Access Approach

Partial control is exercised to the level that, in addition to intersections with selected public
roads, some crossings and private driveways may be allowed.

530.04(4)(a) Approach Types

Partial control limited access highways allow at-grade intersections with selected public roads,
trails/shared-use paths, and private approaches using Type A, B, C, and F approaches. (See
Chapter 520 for the definitions of approach types.)

Type D, commercial approaches, are not allowed direct access to partial control limited access
highways. Commercial access is allowed only by way of other public roads.

The type of approach provided for each parcel is based on current and potential land use and on
an evaluation that assesses connectivity for all modes. (See 530.05(4) for a list of evaluation
criteria.)
530.04(4)(b) Design Considerations

The following considerations are used to determine the number and location of access
approaches on partial control limited access highways.
1. Access approaches must be held to a minimum. The number is limited as follows:
 Principal arterial: two per side per mile
 Minor arterial: four per side per mile
 Collector: six per side per mile, including at-grade intersections
2. Approaches in excess of the number listed above may be allowed as staged construction
(until full buildout is complete) if approved by the Director & State Design Engineer,
Development Division.

3. Approaches are not allowed for parcels that have reasonable access to other public roads
unless a parcel has extensive highway frontage.

4. Relocate or close approaches in areas where sight limitations create undue hazards.

5. Allow only one approach for each parcel, except for very large ownerships, or where
terrain features do not allow the property to be served by a single approach. This includes
contiguous parcels under a single ownership.

6. Where possible, locate a single approach to serve two or more parcels.

7. The approved design is to provide for future development of frontage roads that will
eliminate an excessive number of approaches.

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530.04(5) Location of Utilities, Bus Stops, and Mailboxes

530.04(5)(a) Utilities

Connecting utility lines are allowed along the outer right of way line between intermittent
frontage roads. (See the Utilities Accommodation Policy regarding the location of and access to
utilities.)

530.04(5)(b) Bus Stops

Bus stops for both common carriers and school buses are not allowed on either two-lane or
four-lane highways except:
 At railroad crossings (see Chapter 1350).
 At locations of intersections with necessary pullouts to be constructed by the state.
 Where shoulder widening has been provided for mail delivery service.
 For a designated school bus loading zone on or adjacent to the traveled lane, that has
been approved by WSDOT.

Buses are not allowed to stop in the traveled lanes blocking at-grade intersections or private
approaches to load or unload passengers.

School bus loading zones on partial control limited access highways must be posted with school
bus loading zone signs, in accordance with the latest edition of the Manual on Uniform Traffic
Control Devices (MUTCD).

530.04(5)(c) Mailboxes

Locate mailboxes on frontage roads or at intersections, with the following exceptions for
properties that are served by Type A or B approaches:
 Locate mailboxes on a four-lane highway only on the side of the highway on which the
deeded approach is provided.
 Locate mailboxes on a two-lane highway on the side of the highway that is on the right
in the direction of the mail delivery.

Wherever mailboxes are allowed on a partial control limited access highway, provide mailbox
turnouts to allow mail delivery vehicles to stop clear of the through traffic lanes.
(See Chapter 1600 for additional information concerning mailbox locations and turnouts.)

530.04(6) Pedestrian and Bicyclist Crossings and Paths

Pedestrian and bicyclist crossings are allowed on partial control limited access highways when
they are grade-separated.

At-grade pedestrian and bicyclist crossings are allowed:

 Only at intersections where an at-grade crossing is provided in accordance with
Chapter 1510.
 On two-lane highways at mailbox locations.

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 On two-lane highways not less than 100 feet from a school bus loading zone (pullout)
adjacent to the traveled lane, if school district and WSDOT personnel determine that
the bus stopping in the traveled lane is hazardous.
 On two-lane highways where the school bus is stopped on the traveled lane to load or
unload passengers and the required sign and signal lights are displayed.

On partial control limited access highways, pedestrian and bicyclist traffic is allowed, consistent
with “Rules of the Road” (RCW 46.61), except where unusual safety conditions support
prohibition. Information pertaining to such prohibitions is available from the WSDOT website:
http://wsdot.wa.gov/bike/closed.htm

Paths and trails, and access to and from, within a partial control limited access highway are best
planned and designed with the local agency’s participation. Where existing and future planned
paths are allowed, they must be documented on the right of way and limited access plan. The
plan shows the location of the existing or proposed path and where the path crosses limited
access, and it provides movement notes (see 530.10(1)), with the intention of maintaining and
improving active transportation connectivity.

530.05 Modified Control (Least Restrictive)

530.05(1) Introduction
Modified control is intended to prevent further deterioration in the safety and motor vehicle
operational characteristics of existing highways by limiting the number and location of access
points.

Upon acquisition of modified control limited access, the number, type, and use of access
approaches of abutting property are frozen. The abutting property access rights and type of use
are recorded on the property deed. The rights and use may not be altered by the abutting
property owner, the local jurisdiction, or the region. This authority resides with the Director &
State Design Engineer, Development Division (see 530.10).

530.05(2) Application
In general, modified control is applied where some level of control is desired, but existing and
potential commercial development precludes the implementation of full or partial control.

530.05(2)(a) Existing Highways

Modified control may be established and acquired on existing highways other than main line
interstate. Priority is given to highway segments where one or more of the following conditions
applies:
 Commercial development potential is high, but most of the adjoining property remains
undeveloped.
 There is a reasonable expectation that the adjoining property will be redeveloped to a
more intensive land use, resulting in greater motor vehicle traffic congestion and
increased presence of people walking, bicycling, and/or accessing transit service.
 At interchange areas if full or partial access cannot be provided as described in
530.03(3)(d).

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530.05(2)(b) Modified Control Evaluation

Selection of highways on which modified control may be applied is based on an evaluation that
includes the following contextual factors for all modes:
 The current form of managed access control
 Traffic volumes
 Level of service, or other selected mobility performance metric
 Selected safety performance
 Functional class
 Route continuity
 Mix of residential, destination and employment densities
 Operational considerations related to achieving the selected motor vehicle target
speed
 Operational considerations related to transportation efficiency for people utilizing
active transportation
 Local land use planning
 Current and potential land use
 Predicted growth rate
 Economic analysis

530.05(2)(c) Exceptions

Where modified control is to be established, developed commercial areas may be excepted

from control when all or most of the abutting property has been developed to the extent that
few, if any, additional commercial approaches will be needed with full development of the area.
Contact the HQ Access and Hearings Section when considering this option. If this exception is
within the limits of access control, an approved access design analysis is required.

530.05(3) Intersections
At an intersection on a modified control limited access highway, access control will be
established and acquired along the crossroad for a minimum distance of 130 feet:
 Measured from the centerline of a two-lane highway (see Exhibit 530-3b).
 Measured from the centerline of the nearest directional roadway of a four-lane
highway (see Exhibit 530-3b).
 Measured from the outside edge of the circulating roadway of a roundabout (see
Exhibit 530-3a).

Approaches are allowed within this area only when there is no reasonable alternative. An
approved access design analysis is required for any access that has been allowed to remain
within the first 130 feet. Where appropriate, address and incorporate connectivity for shared-
use paths, trails and sidewalks in and beyond the control area.

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530.05(4) Access Approach

The number and location of approaches on a highway with modified control must be carefully
planned and monitored to provide a safe and efficient highway compatible with present and
potential land use.

530.05(4)(a) Approach Types

Modified control limited access highways allow at-grade intersections with selected public
roads, shared-use paths/trails, and with private approaches using Type A, B, C, and D
approaches. (See Chapter 520 for definitions of the approach types.)

The type of approach provided for each parcel is based on present and potential land use and an
evaluation of the following criteria:
 Local comprehensive plans, zoning, and land use ordinances
 Property covenants and agreements
 City or county ordinances
 The highest and best use of the property
 The highest and best use of adjoining lands
 A change in use by merger of adjoining ownerships
 All other factors bearing upon proper land use of the parcel

530.05(4)(b) Design Considerations

The following items are used to determine the number and location of approaches:
1. Parcels that have access to another public road or street are not normally allowed direct
access to the highway.
2. Meets sight distance criteria (see Chapter 1340).
3. Hold the number of access approaches to a minimum. Access approaches are limited to one
approach for each parcel of land or where adjoining parcels are under one contiguous
ownership.
4. Encourage joint use of access approaches where similar use of land and topography allows.
5. Additional approaches may be allowed for future development consistent with local zoning.
Once limited access has been acquired, this will require a value determination process (see
530.10).

Close existing access approaches not meeting the above.

530.05(5) Location of Utilities, Bus Stops, and Mailboxes

530.05(5)(a) Utilities

Connecting utility lines are allowed along the outer right of way line between intermittent
frontage roads. (See the Utilities Accommodation Policy regarding location of and access to
utilities.)

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530.05(5)(b) Bus Stops

Bus stops are allowed as follows:

 In rural areas, bus stops are subject to the same restrictions as in 530.04(5) and (6).
 In urban areas, bus stops for both commercial carriers and school buses are allowed.
(See Chapter 1430 for transit stop considerations and pullout designs.)

530.05(5)(c) Mailboxes

Locate mailboxes adjacent to or opposite all authorized approaches as follows:

 On a four-lane highway only on the side of the highway on which the deeded approach
is provided.
 On a two-lane highway on the side of the highway that is on the right in the direction
of the mail delivery.

Where mailboxes are allowed, a mailbox turnout is recommended to allow mail delivery vehicles
to stop clear of the through traffic lanes. (See Chapter 1600 for additional information
concerning mailbox locations and turnouts.)

530.05(6) Pedestrian and Bicyclist Crossings and Paths Pedestrian and

Bicycle Traffic and Paths
Pedestrian and bicyclist crossings are allowed as follows.

Pedestrians and bicyclists are allowed, consistent with “Rules of the Road” (RCW 46.61), on
modified control limited access highways except where unusual safety considerations support
prohibition. Information pertaining to such prohibitions is available from the WSDOT website:
http://wsdot.wa.gov/bike/closed.htm

Paths and trails, and access to and from, within a modified control limited access highway are
best planned and designed with the local agency’s participation. Where existing or future
planned paths are allowed, they must be documented in the right of way and limited access
plan. The plan shows the location of the existing or proposed path and where the path crosses
limited access, and it provides movement notes (see 530.10(1)) with the intention of
maintaining and improving active transportation connectivity.

530.06 Access Approaches

530.06(1) General
Access approaches may be allowed on limited access highways, consistent with the
requirements outlined in 530.03, 530.04, and 530.05.

For additional information pertaining to approaches, refer to Chapters 1320 (roundabouts),

1340 (approach design templates), and 510 (right of way), and the Plans Preparation Manual.

The widths for the approach types are negotiated, and only the negotiated widths are shown on
the right of way and limited access plan. (See Chapter 520 for definitions of the approach types.)

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530.07 Frontage Roads

Local agency approval is required for any planned frontage roads, county roads, city streets,
cul-de-sacs, or shared-use paths/trails. The local agency must also agree in writing to accept and
maintain the new section as a county road or city street.

530.07(1) General
Frontage roads are provided in conjunction with limited access highways to:
 Limit access to the main line.
 Provide access to abutting land ownerships.
 Restore the continuity of the local street or roadway system and active transportation
network.

Refer to Chapter 1210 for frontage road general policy and Chapter 300 for required
documentation.

By agreement under which the state is reimbursed for all costs involved, frontage roads that are
not the responsibility of the state may be built by the state upon the request of a local political
subdivision, a private agency, or an individual.

530.07(2) County Road and City Street

To connect roads or streets or walk/bike connections that have been closed off by the highway,
short sections of county roads, city streets, or shared-use paths/trails that are not adjacent to
the highway may be constructed if they will serve the same purpose as, and cost less than, a
frontage road.

530.07(3) Cul-de-sacs
For a frontage road or local street bearing substantial traffic that is terminated or closed at one
end, provide a cul-de-sac or other street or roadway consistent with local policy or practice, that
is sufficient to allow vehicles to turn around without encroachment on private property.
Consider and address continued connectivity and provision of alternate routes for pedestrians
and bicyclists.

530.08 Turnbacks
When WSDOT transfers jurisdiction of operating right of way to a city, town, or county, a
turnback agreement is required. (See the Agreements Manual for turnback procedures.)

Locate the turnback limits at points of logical termination. This will allow WSDOT to retain an
adequate amount of right of way for maintenance of the highway and for other operational
functions.

In areas where limited access rights have been acquired from the abutting property owners, the
limited access rights will continue to be required for highway purposes; therefore, the limited
access rights will not be included as part of a turnback agreement.

When a signalized intersection is in the area of a turnback, locate the turnback limit outside the
detector loops if WSDOT is continuing the ownership, operation, and maintenance of the signal

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system. For a roundabout, locate the turnback limit at the back of the raised approach splitter
island if WSDOT is continuing the ownership, operation, and maintenance of the roundabout.

530.09 Adjacent Railroads

530.09(1) General
A limited access highway and a railroad are considered adjacent when they have a common
right of way border with no other property separating them. The allowed approaches apply only
to adjacent railroad property that is directly used for current railroad operation.

530.09(2) Requirements
It is in the public’s interest to provide access to the railroad right of way, from limited access
highways, for maintenance of the railroad and the utilities located on the railroad right of way
where other access is not feasible. This applies to both new highways and to existing highways
where limited access has been acquired.

Direct access is allowed where local roads are infrequent or there are few highway-railroad
crossings from which trail-type access for maintenance purposes is feasible, and where unique
topography or other unusual conditions lead to its use.

To provide direct approaches for access to railroad right of way, all of the following conditions
must be met:
 A maximum of one approach is allowed for every 2 miles of highway.
 The approach must not adversely affect the design, construction, stability, traffic
safety, or operation of the highway.
 Except where the railroad is located in the median area, the approach is to be
accomplished in a legal manner by right turns only, to and from the roadway nearest
the railroad. Median crossing is not allowed.
 The approach is secured by a locked gate under arrangements satisfactory to the
department. (See the Definitions section in Chapter 520 for Approach Type C, and
Chapter 550.)
 The parking of any vehicles or railroad equipment is prohibited within limited access
highway right of way.
 A special emergency maintenance permit must be obtained for periods of intensive
railroad maintenance.
 The approach must be closed if the railroad operation ceases.
 Approaches are limited to use by the railroad company unless specific provisions for
other use are shown on the right of way and limited access plan and included in the
right of way negotiations.

530.09(3) Restrictions
Direct access to a railroad from the highway is considered unnecessary and is not allowed
where:

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 There are local roads adjacent to or crossing the railroad.

 A trail-type road can be provided by the railroad between crossroads.
 The limited access highway is paralleled by a frontage road adjacent to the railroad.
 No highway previously existed adjacent to the railroad.

530.10 Access Breaks and Inner Corridor Access

This section addresses three topics:
 530.10(1) applies to access breaks and inner corridor access of limited access rights of
way on full, partial and modified highways.
 530.10(2) provides specific detail on changes for private approaches.
 530.10(3) provides specific guidance on changes for public approaches.

530.10(1) General
When non-highway purpose activities are proposed that involve either crossing limited access
boundaries or entering into roadside areas from within limited access facilities, a formal request
shall be approved prior to the activity or use. The request will be either an access break or an
inner corridor access.

An access break is needed when the limited access boundary is to be crossed. This refers to any
point from inside or outside the state limited access right of way limited access hachures that
crosses over, under, or physically through the plane of the limited access.

An inner corridor access is needed when entry into roadside areas inside of the limited access
corridor is to be made from within the limited access boundary. Inner corridor access may be
from a mainline, a ramp, or from a local road or street that is also within limited access.

Evaluate the following factors concerning a potential access break or inner corridor access:
 Crash potential for all modes, including how crash types and contributing factors and
how operational considerations related to the access break would change
 Level of access control (full, partial, or modified)
 Existing and planned land use changes
 Functional classification
 Land use and zoning
 Environment impacts/mitigation
 Determination from a Corridor Sketch, Basis of Design and/or CMAR

Regional staff or Program staff work with the requesting party to compile and submit access
break and inner corridor access requests to the HQ Access and Hearings Section. The request
package will contain the completed access request checklist and all supporting documents and
will be submitted electronically using instructions located on the Access and Hearings Section
website: www.wsdot.wa.gov/design/accessandhearings

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530.10(1)(a) Approvals

Access breaks (either temporary or permanent) and inner corridor access for all limited access
state highways require approval prior to implementation.

For permanent access breaks or inner corridor access approvals involving existing property
rights, the right of way and limited access plan must be revised and deeds may need to be
rewritten.

On non-interstate limited access routes, WSDOT HQ approves access breaks and inner corridor
access.

On interstate routes, 23 CFR 710.403 requires prior approval from FHWA. Note that any changes
proposed on Interstate limited access facilities must include environmental documentation in
the request, as required by FHWA. Contact the HQ Access and Hearings Section for assistance.

530.10(2) Changes for Private Access Approaches (Modified/Partial

Control Only)
Private accesses are allowed within modified control and sometimes allowed within partial
control (WAC 468-58-010).

530.10(2)(a) Requirements

Examples of access modifications requested by abutting property owners include additional

road approaches, changes in the allowed use, or additional users of existing road approaches.

Plan revisions that provide for additional access to abutting properties after WSDOT has
purchased the access rights are discouraged. However, these revisions may be considered if the
following can be established:
 There are no other reasonable alternatives.
 The efficiency and safety of the highway will not be adversely impacted.
 The existing situation causes extreme hardship on the owner(s).
 The revision is consistent with the limited access highway requirements.

530.10(2)(b) Procedures

The region initiates a preliminary engineering review of the requested modification to or break
in limited access and contacts the HQ Access and Hearings Section to determine whether
conceptual approval can be granted for the request. If conceptual approval can be granted,
then:
 The region initiates an engineering review of the requested modification.
 The region prepares and submits to the HQ Right of Way Plans Section a preliminary
right of way and limited access plan revision, together with a recommendation for
Headquarters approval. When federal-aid funds are involved in any phase of the
project, the proposed modification will be sent to FHWA for review and approval.
 The recommendation will include an item-by-item analysis of the factors listed in
530.10(1) and 530.10(2)(a).

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530.10(2)(c) Valuation Determination

Upon preliminary approval, region Real Estate Services prepares an appraisal for the value of the
access change using a before and after appraisal.
 The appraisal follows the requirements set forth in the Right of Way Manual.
 The appraisal package is sent to HQ Real Estate Services for review and approval.
 If federal-aid funds were involved in purchasing access control, HQ Real Estate Services
will send a copy of the appraisal package to FHWA for review and approval.
530.10(2)(d) Final Processing
 Region Real Estate Services informs the requester of the approved appraised value for
the change.
 If the requester is still interested, the region prepares a “Surplus Disposal Package” for
HQ Real Estate Services’ review and approval.
 At the same time, the preliminary right of way and limited access plan revision
previously transmitted is processed for approval.
 After the department collects the payment from the requester, the region issues a
permit for the construction, if required.
 If an existing approach is being surrendered, region Real Estate Services obtains a
conveyance from the property owner.
 HQ Real Estate Services prepares and processes a deed granting the change to the
access rights.

530.10(3) Changes for Public At-Grade Intersections (Modified/Partial

Control Only)
530.10(3)(a) Requirements
 Public at-grade intersections on partial or modified control limited access highways
serve local arterials that form part of the local transportation network for all modes.
 Requests for new intersections on limited access highways must be made by or
through the local governmental agency to WSDOT. The region will forward this
request, including the data referenced in 530.10(1) and 530.10(2)(a) to the HQ Access
and Hearings Section.
 WSDOT must comply with the hearing, or waiver, process as outlined in Chapter 210
and discussed in Section 530.02(2)a. The access acquisition and conveyance must be
completed prior to beginning construction of the new intersection. The new
intersection is to meet WSDOT design and spacing requirements, unless otherwise
approved through design analysis document.
530.10(3)(b) Procedures
 The region evaluates the request for modification and contacts the HQ Access and
Hearings Section for conceptual approval.

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 The region submits an intersection plan for approval (see Chapter 1310) and a right of
way and limited access plan revision request (see the Plans Preparation Manual). This
plan includes the limited access design requirements for all modes along the proposed
public at-grade intersection.
 The Director & State Design Engineer, Development Division, approves the intersection
plan.
 The Assistant Secretary, Regions and Mega Programs/Chief Engineer (or designee),
approves the access revision.
 The region submits the construction agreement to the Director & State Design
Engineer, Development Division (see the Agreements Manual).
 The Assistant Secretary, Regions and Mega Programs/Chief Engineer (or designee),
approves the construction agreement.

530.10(3)(c) Valuation Determination

 When a requested public at-grade intersection will serve a local arterial that
immediately connects to the local transportation network, compensation will not be
required.
 When a requested public at-grade intersection will serve only a limited area, does not
immediately connect to the local transportation network, or is primarily for the benefit
of a limited number of developers, compensation for the access change will be
addressed in the plan revision request. In these situations, compensation is appropriate
and a value will be determined as outlined in 530.10(2)(c).

530.11 Documentation
Refer to Chapters 210, 300, and 550 for design documentation requirements.

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Exhibit 530-1a Full Access Control Limits: Interchange

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Exhibit 530-1b Full Access Control Limits: Interchange

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Exhibit 530-1c Full Access Control Limits: Interchange with Roundabouts

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Exhibit 530-1d Full Access Control Limits: Ramp Terminal with Transition Taper

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Exhibit 530-1e Full Access Control Limits: Single Point Urban Interchange

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Exhibit 530-1f Full Access Control Limits: Diverging Diamond Interchange

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Exhibit 530-2a Partial Access Control Limits: At-Grade Intersections

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Exhibit 530-2b Partial Access Control Limits: Roundabout Intersections

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Exhibit 530-3a Modified Access Control Limits: Roundabout Intersections

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Exhibit 530-3b Modified Access Control Limits: Intersections

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540.01 General 540.07 Permitting and Design Documentation
540.02 Design Considerations 540.08 Other Considerations
540.03 Managed Access Highway Classes 540.09 Preconstruction Conference
540.04 Corner Clearance Criteria 540.10 Adjudicative Proceedings
540.05 Access Connection Categories 540.11 Documentation
540.06 Access Connection Permit 540.12 References

540.01 General
Access management is the systematic regulation of the location, spacing, design, and operation
of driveway, city street, and county road connections to state highways. This chapter describes
the access management process for granting permission to connect to managed access
highways within cities and unincorporated areas. For an overview of access control, references
to related state laws and codes, and definitions of terminology for this chapter, see Chapter 520,
Access Control.

In Washington State, managed access highways include all state highways that are not limited
access highways. State highways that are planned for or established as limited access, are
treated as managed access highways until the limited access rights are acquired.

The Access Control Tracking System Limited Access and Managed Access Master Plan (Access
Master Plan) identifies not only the limits of limited access control, but also managed access
control segments. The current managed access classification is based on access connection
densities, distance between access connections, spacing of intersections, and context (see
Washington Administrative Code (WAC) 468-52-040). The existing access classification is
periodically updated by Headquarters (HQ) with region input to reflect changes on a corridor
segment. Conditions may have changed since the Access Master Plan was envisioned or the last
managed access classification update. On non-freeways it is important to consider the current
classification and any classifications previously planned, and determine the access design
control most appropriate for the agreed context (see Chapters 1102 and 1103 for context and
design control guidance, respectively). The Access Master Plan database is available at:
 www.wsdot.wa.gov/design/accessandhearings

Access to managed access highways is regulated by the governmental entity with jurisdiction
over a highway’s roadsides. Access connection permits are issued on managed access highways.
The Washington State Department of Transportation (WSDOT) has access connection permitting
authority over all state highways outside incorporated towns and cities. Incorporated towns and
cities have access connection permitting authority for city streets that are part of state
highways, as specified in Revised Code of Washington (RCW) 47.24.020. When any project is
developed on a state highway outside an incorporated city or town, state law requires that
existing access connections be evaluated to determine whether they are consistent with all
current department spacing, location, and design standards (see 540.03).

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540.02 Design Considerations

Evaluate access connections by using the Access Master Plan database to identify the route
classification and determine access connection requirements in conformance with this chapter
or Chapter 530 as appropriate. See also Chapter 1100, Practical Design, and chapters in that
series for guidance on how access control is used as a design control.

Review all connections and verify whether they are in the Roadway Access Management Permit
System (RAMPS) database. Contact the region Development Services Office or the HQ Access
and Hearings Section for permission to log on to the link through this page:
 www.wsdot.wa.gov/design/accessandhearings

If a nonconforming connection is identified, consider relocating, modifying, or eliminating the

connection. It is not the intent of the managed access program that modifications to the
connection will change the general functionality of the property.

Where current department standards cannot be met while providing the same general
functionality, classify the connection as nonconforming and process the appropriate
documentation as discussed below. This documentation is part of the permit process.

540.03 Managed Access Highway Classes

The principal objective of the managed access classification system is to maintain the safety and
capacity of existing highways. This is accomplished by establishing access management criteria,
which are to be adhered to in the planning and regional approval of access connections to the
state highway system.

The classification system for state managed access highways consists of five classes. The classes
are arranged from the most restrictive, Class 1, to the least restrictive, Class 5. In general, most
state highways outside the incorporated limits of a city or town have been designated as Class 1
or Class 2, with only the most urban and lowest-speed state highways within an incorporated
town or city designated as Class 5. Exhibit 540-1 shows the five classes of highways, with a brief
description of each class. WSDOT keeps a record of the assigned managed access classifications,
by state route and milepost, in the Access Control Tracking System database:
 www.wsdot.wa.gov/design/accessandhearings

One of the goals of state law is to restrict or keep access connections to a minimum in order to
help preserve the safety, operation, and functional integrity of the state highway. On Class 1
highways, mobility is the primary function, while on Class 5 highways, access needs have priority
over mobility needs. Class 2 highways also favor mobility, while Class 3 and Class 4 highways
generally achieve a balance between mobility and access.

The most notable distinction between the five highway classes is the minimum spacing
requirements of access connections. Exhibit 540-1 shows the minimum distances between
access points on the same side of the highway. Exhibit 540-2 applies to the minimum clearance
from a public road or street.

In all five highway classes, access connections are to be located and designed to minimize
interference with transit facilities and high-occupancy vehicle (HOV) facilities on state highways
where such facilities exist or are proposed in state, regional, metropolitan, or local
transportation plans. In these cases, if reasonable access is available to the local road/street

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system, access is to be provided to the local road/street system rather than directly to the state
highway. Following are the functional characteristics and the legal requirements for each class.

540.03(1) Class 1
540.03(1)(a) Functional Characteristics

Class 1 highways provide for high-speed and/or high-volume traffic movements for interstate,
interregional, and intercity (and some intracity) travel needs. Service to abutting land is
subordinate to providing service to major traffic movements.

Highways in Class 1 are typically distinguished by a highly-controlled, limited number of (public

and private) access points, restrictive medians with limited median openings on multilane
facilities, and infrequent intersections.
540.03(1)(b) Legal Requirements

1. It is the intent that Class 1 highways be designed to have a posted speed limit of 50 to
65 mph. Intersecting streets, roads, and highways are planned with a minimum spacing
of 1 mile. Spacing of ½ mile may be allowed, but only when no reasonable alternative access
exists.

2. Private access connections to the state highway are not allowed except where the property
has no other reasonable access to the local road/street system. When a private access
connection must be provided, the following conditions apply:
 The access connection continues until such time other reasonable access to a
highway with a less restrictive access control class or access to the local road/street
system becomes available and is allowed.

 The minimum distance to another (public or private) access point is 1,320 feet
along the same side of the highway. Nonconforming access connection permits
may be issued to provide access connections to parcels whose highway frontage,
topography, or location otherwise precludes issuance of a conforming access
connection permit; however, variance permits are not allowed.
 No more than one access connection may be provided to an individual parcel or to
contiguous parcels under the same ownership.

 All private access connections are for right turns only on multilane facilities. Where
special conditions apply, justify the exception in a traffic analysis in the access
connection permit application that is signed and sealed by a qualified professional
engineer who is registered in accordance with RCW 18.43.
 Additional access connections to the state highway are not allowed for newly
created parcels resulting from property divisions. All access for these parcels must
be provided by an internal road/street network. Access to the state highway will be
at existing permitted locations or revised locations.

3. Restrictive medians are provided on multilane facilities to separate opposing traffic

movements and to prevent unauthorized turning movements.

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540.03(2) Class 2
540.03(2)(a) Functional Characteristics

Class 2 highways provide for medium-to-high-speed and medium-to-high-volume traffic

movements over medium and long distances for interregional, intercity, and intracity travel
needs. Direct access service to abutting land is subordinate to providing service to traffic
movements.

Highways in Class 2 are typically distinguished by existing or planned restrictive medians on

multilane facilities and by large minimum distances between (public and private) access points.
540.03(2)(b) Legal Requirements

1. It is the intent that Class 2 highways be designed to have a posted speed limit of 35 to
50 mph in urbanized areas and 45 to 55 mph in rural areas. Intersecting streets, roads,
and highways are planned with a minimum spacing of ½ mile. Intersection spacing of less
than ½-mile may be allowed, but only when no reasonable alternative access exists.

In urban areas and developing areas where higher volumes are present or growth that will
require a change to intersection control is expected in the foreseeable future, it is
imperative that the location of any public access point be planned carefully to ensure
adequate traffic progression. The addition of all new public or private access points that
might require signalization or other form of intersection control will require an engineering
analysis that is signed and sealed by a qualified professional engineer who is registered in
accordance with RCW 18.43.

2. Private access connections to the state highway system are allowed only where the property
has no other reasonable access to the local road/street system or where access to the local
road/street system will cause unacceptable traffic operational conditions or safety concerns
on that system. When a private access connection must be provided, the following
conditions apply:
 The access connection continues until such time other reasonable access to a
highway with a less restrictive access control class or acceptable access to the local
road/street system becomes available and is allowed.
 The minimum distance to another (public or private) access point is 660 feet on the
same side of the highway. Nonconforming access connection permits may be
issued to provide access to parcels whose highway frontage, topography, or
location precludes issuance of a conforming access connection permit.

 Only one access connection is allowed for an individual parcel or to contiguous

parcels under the same ownership. This applies unless the highway frontage
exceeds 1,320 feet and it can be shown that the additional access connection will
not adversely affect the desired function of the state highway in accordance with
the assigned managed access Class 2 or the safety or operation of the state
highway.

 Variance permits may be allowed if there are special conditions and the exception
can be justified to the satisfaction of the department by a traffic analysis in the

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access connection permit application that is signed and sealed by a qualified

professional engineer who is registered in accordance with RCW 18.43.
 All private access connections are for right turns only on multilane facilities. This
applies unless there are special conditions and the exception can be justified to the
satisfaction of the department by a traffic analysis in the access connection permit
application that is signed and sealed by a qualified professional engineer who is
registered in accordance with RCW 18.43 and only if left-turn channelization is
provided.
 Additional access connections to the state highway are not allowed for newly
created parcels that result from property divisions. All access for these parcels
must be provided by an internal road/street network. Access to the state highway
will be at existing permitted locations or at revised locations.

3. On multilane facilities, restrictive medians are provided to separate opposing traffic

movements and to prevent unauthorized turning movements. However, a nonrestrictive
median or a two-way left-turn lane may be used where special conditions exist and main
line volumes are below 20,000 average daily traffic (ADT).

540.03(3) Class 3
540.03(3)(a) Functional Characteristics

Class 3 highways provide for moderate travel speeds depending on context, and moderate
traffic volumes for medium and short travel distances for intercity, intracity, and
intercommunity travel needs. There is a reasonable balance between access and mobility needs
for highways in this class. This class is to be used primarily where the existing level of
development of the adjoining land is less intensive than maximum buildout and where the
probability of significant land use change and increased traffic demand is high.

Highways in Class 3 are typically distinguished by planned restrictive medians on multilane

facilities and by meeting minimum distances between (public and private) access points. Two
way left-turn lanes may be used where justified and main line traffic volumes are below 25,000
ADT. Development of properties with internal road/street networks and joint access
connections is encouraged.

540.03(3)(b) Legal Requirements

1. It is the intent that Class 3 highways be designed to have a posted speed limit of 30 to 40
mph in urbanized areas and 45 to 55 mph in rural areas. In rural areas, intersecting streets,
roads, and highways are planned with a minimum spacing of ½ mile. Intersection spacing of
less than ½-mile may be allowed, but only when no reasonable alternative access exists.

In urban areas and developing areas where higher volumes are present or growth that will
require a change to intersection control is expected in the foreseeable future, it is
imperative that the location of any public access point be planned carefully to ensure
adequate traffic progression. Where feasible, major intersecting roadways that might
ultimately require signalization or other intersection control type are planned with a
minimum of ½-mile spacing. The addition of all new public or private access points that may
require signalization or other intersection control type, will require an engineering analysis

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that is signed and sealed by a qualified professional engineer who is registered in

accordance with RCW 18.43.

2. Private Access Connections

 No more than one access connection may be provided to an individual parcel or to
contiguous parcels under the same ownership. This applies unless it can be shown
that additional access connections will not adversely affect the desired function of
the state highway in accordance with the assigned managed access Class 3 and will
not adversely affect the safety or operation of the state highway.

 The minimum distance to another (public or private) access point is 330 feet on the
same side of the highway. Nonconforming access connection permits may be
issued to provide access to parcels whose highway frontage, topography, or
location precludes issuance of a conforming access connection permit.

 Variance permits may be allowed if there are special conditions and the exception
can be justified to the satisfaction of the department by a traffic analysis in the
access connection permit application that is signed and sealed by a qualified
professional engineer who is registered in accordance with RCW 18.43.

540.03(4) Class 4
540.03(4)(a) Functional Characteristics

Class 4 highways provide for moderate travel speeds and moderate traffic volumes for medium
and short travel distances for intercity, intracity, and intercommunity travel needs. There is a
reasonable balance between direct access and mobility needs for highways in this class. This
class is to be used primarily where the existing level of development of the adjoining land is
more intensive and where the probability of major land use changes is less than on Class 3
highway segments.

Highways in Class 4 are typically distinguished by existing or planned nonrestrictive medians.

Restrictive medians may be used to mitigate unfavorable operational conditions such as turning,
weaving, and crossing conflicts. Minimum access connection spacing requirements apply if
adjoining properties are redeveloped.

540.03(4)(b) Legal Requirements

1. It is the intent that Class 4 highways be designed to have a posted speed limit of 30 to 35
mph in urbanized areas and 35 to 45 mph in rural areas. In rural areas, intersecting streets,
roads, and highways are planned with a minimum spacing of ½ mile. Intersection spacing of
less than ½ mile may be allowed, but only when no reasonable alternative access exists.

In urban areas and developing areas where higher volumes are present or growth that will
require a change in intersection control is expected in the foreseeable future, it is
imperative that the location of any public access point be planned carefully to ensure
adequate traffic progression. Where feasible, major intersecting roadways that might
ultimately require intersection control changes are planned with a minimum of ½-mile
spacing. The addition of all new public or private access points that may require
signalization, or other intersection control type, will require an engineering analysis that is

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signed and sealed by a qualified professional engineer who is registered in accordance with
RCW 18.43.

2. Private Access Connections

 No more than one access connection may be provided to an individual parcel or to
contiguous parcels under the same ownership. This applies unless it can be shown
that additional access connections will not adversely affect the desired function of
the state highway in accordance with the assigned managed access Class 4 and will
not adversely affect the safety or operation of the state highway.

 The minimum distance to another (public or private) access point is 250 feet on the
same side of the highway. Nonconforming access connection permits may be
issued to provide access connections to parcels whose highway frontage,
topography, or location precludes issuance of a conforming access connection
permit.
 Variance permits may be allowed if there are special conditions and the exception
can be justified to the satisfaction of the department by a traffic analysis in the
access connection permit application that is signed and sealed by a qualified
professional engineer who is registered in accordance with RCW 18.43.

540.03(5) Class 5
540.03(5)(a) Functional Characteristics

Class 5 highways provide for moderate travel speeds and moderate traffic volumes for primarily
short travel distances for intracity and intracommunity trips and for access to state highways of
a higher class. Access needs generally may be higher than the need for through-traffic mobility
without compromising the public’s health, welfare, or safety. These highways will normally have
nonrestrictive medians.

540.03(5)(b) Legal Requirements

1. It is the intent that Class 5 highways be designed to have a posted speed limit of 25 to 35
mph. In rural areas, intersecting streets, roads, and highways are planned with a minimum
spacing of ¼ mile. Spacing of less than ¼ mile may be allowed where no reasonable
alternative exists. In urban areas and developing areas where higher volumes are present or
growth that will require changes to intersection control is expected in the foreseeable
future, it is imperative that the location of any public access point be planned carefully to
ensure adequate traffic progression. Where feasible, major intersecting roadways that
might ultimately require changes to intersection control are planned with a minimum of ¼
mile spacing. The addition of all new public or private access points that might require
signalization, or other control type, will require an engineering analysis that is signed and
sealed by a qualified professional engineer who is registered in accordance with RCW 18.43.

2. Private Access Connections

 No more than one access connection may be provided to an individual parcel or to
contiguous parcels under the same ownership. This applies unless it can be shown
that additional access connections will not adversely affect the desired function of

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the state highway in accordance with the assigned managed access Class 5 and will
not adversely affect the safety or operation of the state highway.
 The minimum distance to another (public or private) access point is 125 feet on the
same side of the highway. Nonconforming access connection permits may be
issued to provide access to parcels whose highway frontage, topography, or
location precludes issuance of a conforming access connection permit.

 Variance permits may be allowed if there are special conditions and the exception
can be justified to the satisfaction of the department by a traffic analysis in the
access connection permit application that is signed and sealed by a qualified
professional engineer who is registered in accordance with RCW 18.43.

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Exhibit 540-1 Managed Access Highway Class Description

Conforming[1]

Conforming[3]

Access Point
Variance[2]

Spacing**
Class Limitations[4]

Non-
Class 1 • One access only to contiguous
Mobility is the parcels under same ownership
primary function Yes* No No 1,320 ft • Private access connection is not
allowed unless no other reasonable
access exists (must use local road/
street system if possible)
Class 2 • One access connection only to
Mobility is favored contiguous parcels under same
over access ownership unless frontage > 1,320 ft
Yes* Yes* No 660 ft • Private access connection not
allowed unless no other reasonable
access exists; must use local
road/street system if possible
Class 3 • One access connection only
Balance between to contiguous parcels under
mobility and access same ownership
Yes Yes Yes 330 ft
in areas with less • Joint access connection for
than maximum subdivisions preferred; private
buildout connection allowed, with justification
Class 4 One access connection only
Balance between to contiguous parcels under same
mobility and access ownership, except with justification
Yes Yes Yes 250 ft
in areas with less
than maximum
buildout
Class 5 More than one access connection
Access needs may per ownership, with justification
Yes Yes Yes 125 ft
have priority over
mobility
*The access connection continues only until such time other reasonable access to a highway with a less restrictive
class or acceptable access to the local road/street system becomes available and is allowed.

**Minimum, on the same side of the highway.

[1] See 540.07(2).

[2] See 540.07(3).
[3] See 540.07(1).
[4] Unless grandfathered (see 540.06).

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540.03(6) Changes in Managed Access Classification

WSDOT, RTPOs, MPOs, or other entities such as cities, towns, or counties may initiate a review
of managed access classifications per the process identified by WAC 468-52. In all cases, WSDOT
consults with the RTPOs, MPOs, and local agencies and takes into consideration comments
received during the review process. For city streets that are designated as state highways, the
department will obtain concurrence in the final classification assignment from the city or town.

The modified highway classification list shall be submitted to Headquarters for approval by the
Director & State Design Engineer, Development Division, or a designee. WSDOT regions shall
notify the RTPOs, MPOs, and local governmental entities in writing of the final determination of
the reclassification.

540.04 Corner Clearance Criteria

In addition to the five access control classes, there are also corner clearance criteria that must
be used for access connections near intersections (see Exhibit 540-2).

Corner clearance spacing must meet or exceed the minimum access point spacing requirements
of the applicable managed access highway class. A single access connection may be placed
closer to the intersection, in compliance with the permit application process specified in WAC
468-51 and in accordance with the following criteria:
 The minimum corner clearance criteria in Exhibit 540-2 may be used where access
point spacing cannot be obtained due to property size and where a joint-use access
connection cannot be secured or where it is determined by WSDOT not to be feasible
because of conflicting land use or conflicting traffic volumes or operational
characteristics.
 Some local agencies have adopted corner clearance as a design element in their design
standards; these standards are to meet or exceed WSDOT standards. Coordinate with
the local agency regarding corner clearance of an access connection on or near an
intersecting local road or street.
 When a joint-use access connection or an alternate road/street system access—
meeting or exceeding the minimum corner clearance requirements—becomes
available, the permit holder must close the permitted access connection unless the
permit holder shows to WSDOT's satisfaction that such closure is not feasible.

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Exhibit 540-2 Minimum Corner Clearance: Distance From Access Connection to Public
Road or Street

minimum corner
clearance

State Hwy.

public road/street
access connection

With Restrictive Median

Position Access Allowed Minimum (ft)
Approaching Intersection Right In/Right Out 115
Approaching Intersection Right In Only 75
Departing Intersection Right In/Right Out 230*
Departing Intersection Right Out Only 100
Without Restrictive Median
Position Access Allowed Minimum (ft)
Approaching Intersection Full Access** 230*
Approaching Intersection Right In Only 100
Departing Intersection Full Access** 230*
Departing Intersection Right Out Only 100
*125 ft may be used for Class 5 facilities with a posted speed of 35 mph or less.
**Full Access = All four movements (Right in/Right out; Left in/Left out)

540.05 Access Connection Categories

Whenever an access connection permit is issued on a managed access state highway, the permit
must also specify one of four access connection categories: Category I to Category IV. Categories
I through III are based on the maximum vehicular usage of the access connection. Category IV
specifies temporary use, usually for less than a year. Access connection permits must specify the
category and the maximum vehicular usage of the access connection in the permit.

All access connections are determined by WSDOT to be in one of the following categories
(WAC 468-51-040):

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540.05(1) Category I
“Category I – minimum connection” provides connection to the state highway system for up to
ten single-family residences, a duplex, or a small multifamily complex of up to ten dwelling units
that use a common access connection. This category also applies to permanent access
connections to agricultural and forestlands, including field entrances; access connections for the
operation, maintenance, and repair of utilities; and access connections serving other low-
volume traffic generators expected to have average weekday vehicle trip ends (AWDVTE) of 100
or less.

540.05(2) Category II
“Category II – minor connection” provides connection to the state highway system for medium-
volume traffic generators expected to have an AWDVTE of 1,500 or less, but not included in
Category I.

540.05(3) Category III

“Category III – major connection” provides connection to the state highway system for high-
volume traffic generators expected to have an AWDVTE exceeding 1,500.

540.05(4) Category IV
“Category IV – temporary connection” provides a temporary, time-limited connection to the
state highway system for a specific property for a specific use with a specific traffic volume. Such
uses include, but are not limited to, logging, forestland clearing, temporary agricultural uses,
temporary construction, and temporary emergency access. The department reserves the right
to remove any temporary access connection at its sole discretion and at the expense of the
property owner after the expiration of the permit. Further, a temporary access connection
permit does not bind the department, in any way, to the future issuance of a permanent access
connection permit at the temporary access connection location.

540.06 Access Connection Permit

RCW 47.50 requires all access connections to be permitted. This can be accomplished by the
permitting process (see 540.07) or by the connection being “grandfathered” (in place prior to
July 1, 1990).

All new access connections to state highways, as well as alterations and improvements to
existing access connections, require an access connection permit. Every owner of property that
abuts a managed access state highway has the right to reasonable access, but not a particular
means of access. This right may be restricted with respect to the highway if reasonable access
can be provided by way of another local road/street.

When a new private road or street is to be constructed, approval by the permitting authority is
required for intersection design, spacing, and construction work on the right of way. However, if
an access connection permit is issued, it will be rendered null and void if and when the road or
street is duly established as a local road or street by the local governmental entity.

It is the responsibility of the applicant or permit holder to obtain all necessary local, state, and
federal approvals and permits (which includes all environmental permits and documentation).

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The access connection permit only allows the applicant permission to connect to the state
highway. It is also the responsibility of the applicant to acquire any and all property rights
necessary to provide continuity from the applicant’s property to the state highway.

The alteration or closure of any existing access connection caused by changes to the character,
intensity of development, or use of the property served by the access connection or the
construction of any new access connection must not begin before an approved access
connection permit is obtained.

If a property owner or permit holder with a valid access connection permit wishes to change the
character, use, or intensity of the property or development served by the access connection, the
permitting authority must be contacted to determine whether an upgraded access connection
permit will be required.

540.07 Permitting and Design Documentation

An access connection permit is obtained from the department by submitting the appropriate
application form, including the fee, plans, traffic data, and access connection information, to the
department for review. All access connection and roadway design documents for Category II and
III permits must bear the seal and signature of a professional engineer registered in Washington
State.

The permitting process begins with the application. Upon submittal of the application with all
the attached requirements, it is reviewed and either denied or accepted. If denied, the
department must notify the applicant in writing stating the reasons, and the applicant will have
thirty (30) days to submit a revised application. Once the application is approved and the permit
is issued, the applicant may begin construction.

The Access Manager in each region keeps a record of all access points, including those that are
permitted and those that are grandfathered (see 540.08). A permit for a grandfathered access
point is not required but may be issued for recordkeeping reasons.

540.07(1) Conforming Access Connection Permit

Conforming access connection permits may be issued for access connections that conform to
the functional characteristics and all legal requirements for the designated class of the highway.

540.07(2) Nonconforming Access Connection Permit

Nonconforming access connection permits may be issued:
 For short-term access connections pending the availability of a future joint-use access
connection or local road/street system access.
 For location and spacing not meeting requirements.
 For Category I through IV permits.
 After an analysis and determination by the department that a conforming access
connection cannot be made at the time of permit application submittal.
 After a finding that the denial of an access connection will leave the property without a
reasonable means of access to the local road/street system.

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In such instances, the permit is to be noted as being a nonconforming access connection permit
and may contain the following specific restrictions and provisions:
 Limits on the maximum vehicular use of the access connection.
 The future availability of alternate means of reasonable access for which a conforming
access connection permit can be obtained.
 The removal of the nonconforming access connection at the time the conforming
access is available.
 The properties to be served by the access connection.
 Other conditions as necessary to carry out the provisions of RCW 47.50.

540.07(3) Variance Access Connection Permit

Variance access connection is a special nonconforming or additional access connection permit
issued for long-term use where future local road/street system access is not foreseeable:
 For location and spacing not meeting requirements or for an access connection that
exceeds the number allowed for the class.
 After an engineering study demonstrates, to the satisfaction of the department, that
the access connection will not adversely affect the safety, maintenance, or operation of
the highway in accordance with its assigned managed access class.

In such instances, the permit is to be noted as being a variance access connection permit and
may contain the following specific restrictions and provisions:
 Limits on the maximum vehicular use of the access connection
 The properties to be served by the access connection
 Other conditions as necessary to carry out the provisions of RCW 47.50

This permit will remain valid until modified or revoked by the permitting authority unless an
upgraded permit is required due to changes in property site use (see 540.08(1)).

A variance access connection permit must not be issued for an access connection that does not
conform to minimum corner clearance requirements (see 540.04).

540.07(4) Corner Clearance Design Analysis

540.07(4)(a) Outside Incorporated City Limits

A design analysis request will be required for nonconforming access connections if corner
clearance criteria are not met. The ASDE should be involved early in the process. Such an access
will be outside the corner radius and as close as feasible to the property line farthest away from
the intersection.

An exception to the above may be allowed for a single-family residence, serving a single
residence, not meeting the minimum corner clearance criteria and having no feasible
connection to the local cross street. One single family home generates a very low volume of
traffic and will pose a low conflict potential for traffic on the State Highway System. A single-
family access connection exception is to comply with the following criteria:

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 Serves a single residence

 Access is to be outside the corner radius
 Access is to be located as close as feasible to the property line farthest away from the
intersection
 The denial of an access connection would leave the property without a reasonable
means of access.
 The connection is to be relocated to a local road/street system, if one becomes
available.

Document the above criteria in the access connection permit.

540.07(4)(b) Within Incorporated Cities

In accordance with RCW 35.78.030 and RCW 47.50, incorporated cities and towns have
jurisdiction over access permitting on streets designated as state highways and, therefore, no
design analysis by WSDOT will be required. On WSDOT projects, document decisions made on
these accesses in the DDP.

540.08 Other Considerations

540.08(1) Changes in Property Site Use With Permitted Access

Connection
The access connection permit is issued to the permit holder for a particular type of land use
generating specific projected traffic volumes at the final stage of proposed development. Any
changes made in the use, intensity of development, type of traffic, or traffic flow require the
permit holder, an assignee, or the property owner to contact the department to determine
whether further analysis is needed because the change is significant and will require a new
permit and modifications to the access connection (WAC 468-51-110).

A significant change is one that will cause a change in the category of the access connection
permit or one that causes an operational, safety, or maintenance problem on the state highway
system based on objective engineering criteria or available collision data. Such data will be
provided to the property owner and/or permit holder and tenant upon written request (WAC
468-51-110).

540.08(2) Existing Access Connections

540.08(2)(a) Closure of Grandfathered Access Connections

Any access connections that were in existence and in active use on July 1, 1990, are
grandfathered.

The grandfathered access connection may continue unless:

 There are changes from the 1990 AWDVTE.
 There are changes from the 1990 established use.
 The department determines that the access connection does not provide minimum
acceptable levels of highway safety and mobility based on collision and/or traffic data

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or accepted traffic engineering criteria, a copy of which must be provided to the

property owner, permit holder, and/or tenant upon written request (WAC 468-51-130).
540.08(2)(b) Department Construction Projects

540.08(2)(b)(1) Notification

The department must notify affected property owners, permit holders, business owners,
and emergency services in writing, when appropriate, whenever the department’s work
program requires the modification, relocation, or replacement of its access connections. In
addition to written notification, the department will facilitate, when appropriate, a process
that may include, but is not limited to, public notices, meetings, or hearings, as well as
individual meetings.

540.08(2)(b)(2) Modification Considerations

When the number, location, or design of existing access connections to the state highway is
being modified by a department construction project, the resulting modified access
connections must provide the same general functionality for the existing property use as
they did before the modification, taking into consideration the existing site design, normal
vehicle types, and traffic circulation requirements. These are evaluated on an individual
basis.

It is important to remember that the intent is not to damage the property owner by
removing nonconforming access connections, but to eliminate access connections that are
both nonconforming and not needed.

The permitting authority evaluates each property individually to make a determination

about which category of access connection (see 540.05) and which design template (see
Chapter 1340) will be reasonable. If it is a commercial parcel, determine whether the
business can function with one access connection. Each parcel, or contiguous parcels under
the same ownership being used for the same purpose, is allowed only one access
connection. If the business cannot function properly with only one access connection, a
variance permit may be issued for additional access connections. If the property is
residential, only one access connection is allowed; however, certain circumstances might
require an additional access connection (see 540.07(4)(a)).

540.08(2)(b)(3) Costs: Replacement of/Modifications to Existing Access Connections

The costs of modifying or replacing the access points are borne by the department if the
department construction project caused the replacement or modification. Modification of
the connection may require a change to the existing permit.

540.08(3) Work by Permit Holder’s Contractor

The department requires that work by the owner’s contractor be accomplished at the
completion of the department’s contract or be scheduled so as not to interfere with the
department’s contractor. The department may require a surety bond prior to construction of
the access connection in accordance with WAC 468-51-070.

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540.09 Preconstruction Conference

All new access connections, including alterations and improvements to existing access
connections to the highway, require an access connection permit. The permitting authority may
require a preconstruction conference prior to any work being performed on the access. The
preconstruction conference must be attended by those necessary to ensure compliance with
the terms and provisions of the permit. Details regarding the individual access connections will
be included in the construction permit. This may include access connection widths, drainage
requirements, surfacing requirements, mailbox locations, and other information
(WAC 468-51-090).

540.10 Adjudicative Proceedings

Any person who can challenge any of the following departmental actions may request an
adjudicative proceeding (an appeal to an Administrative Law Judge) within thirty (30) days of the
department’s written decision (WAC 468-51-150):
 Denial of an access connection permit application pursuant to WAC 468-51-080
 Permit conditions pursuant to WAC 468-51-150
 Permit modifications pursuant to WAC 468-51-120
 Permit revocation pursuant to WAC 468-51-120
 Closure of permitted access connection pursuant to WAC 468-51-120
 Closure of grandfathered access connection pursuant to WAC 468-51-130

An appeal of a decision by the department can be requested only if the administrative fee has
been paid. If the fee has not been paid, the permit application is considered incomplete and an
adjudicative proceeding cannot be requested.

540.10(1)(a) Adjudicative Proceedings Process

Following is a brief summary of the adjudicative proceeding process. For the purpose of this
summary, the responsibilities of the department are separated into those actions required of
the region and those actions required of Headquarters. The summary is written as if the
appealable condition was a denial of an access connection request.

1. The region receives an access connection permit application, with fee.

2. The region processes the application and makes a determination that the access connection
request will be denied.

3. The region sends the applicant a written letter denying the access connection. Included in
this letter is notification that the applicant has thirty (30) days to request an adjudicative
proceeding if the applicant disagrees with the region’s denial decision. The region must
notify affected property owners, permit holders, business owners, tenants, lessees, and
emergency services, as appropriate.

4. The applicant requests, within thirty (30) days, an adjudicative proceeding.

5. The region reviews its initial denial decision and determines whether there is any additional
information presented that justifies reversing the original decision.

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6. If the region determines that the original denial decision will stand, the region then forwards
copies of all applicable permit documentation to the HQ Development Services & Access
Manager for review and processing.

7. The HQ Development Services & Access Manager reviews the permit application and sends
the permit documentation and appeal request to the Office of the Attorney General (AG).

8. If the initial findings of the AG agree with the region’s denial decision, the AG’s Office sends
the applicant a written letter, with the AG’s signature, informing the applicant that a hearing
will be scheduled for the applicant to appeal in person the department’s decision to deny
access.

9. The region reserves a location and obtains a court reporter, and Headquarters obtains an
Administrative Law Judge (ALJ) to conduct the proceeding. The AG, by written letter, notifies
the applicant of the time and place for the hearing. The AG’s Office has ninety (90) days
from receipt of the applicant’s appeal to approve or deny the appeal application, schedule a
hearing, or decide not to conduct a hearing. The actual hearing date can be set beyond this
ninety-day (90-day) review period.

10. The AG’s Office leads the department’s presentation and works with the region regarding
who will testify and what displays and other information will be presented to the ALJ. The
HQ Development Services & Access Manager will typically not attend these proceedings.

11. After hearing all the facts, the ALJ issues a decision, usually within a few weeks after the
proceedings. However, the ALJ has ninety (90) days in which to serve a written Initial Order
stating the decision.

12. The ALJ’s decision is final unless the applicant, or the department through the HQ
Development Services & Access Manager, decides to appeal the ALJ’s decision to the
Director & State Design Engineer, Development Division. This second appeal must occur
within twenty (20) days of the ALJ’s written decision.

13. If appealed to the Director & State Design Engineer, Development Division, the Director &
State Design Engineer has ninety (90) days to review the Initial Order and all the facts and
supporting documentation and issue a Final Order. The review by the Director & State
Design Engineer does not require the applicable parties to be present and may involve only
a review of the material submitted at the adjudicative proceeding.

14. The Director & State Design Engineer’s decision is final unless appealed within thirty (30)
days to the Washington State Superior Court.

The above represents a general timeline if all appeals are pursued. Based on the noted
timelines, it can take nearly a year before a Final Order is issued. If appealed to Superior Court,
up to an additional 18 months can be added to the process. In any case, contact the region
Development Services Engineer for further guidance and direction if an appeal might be
forthcoming.

540.11 Documentation
Refer to Chapter 300 for design documentation requirements.

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540.12 References

540.12(1) State Laws and Codes

Chapter 520, Access Control, provides reference to laws and codes

540.12(2) Design Guidance

Chapter 520, Access Control

Chapters in the 1100 series for guidance on practical design, context, and design controls

Chapter 1230, Geometric Cross Section

Chapters 1300 and 1310, for intersection design policy and guidance

Chapter 1340, Driveways

Chapter 1600, Roadside Safety

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Chapter 550 Freeway Access Revision
550.01 Overview
550.02 Freeway Access Policy
550.03 Access Revision Analysis Process
550.04 Support Teams
550.05 Non-Access Feasibility Study
550.06 Access Revision Report Process
550.07 Documentation
550.08 References

550.01 Overview
It is in the national and state interest to preserve and enhance the Interstate and non-Interstate
freeway system in Washington providing an appropriate level of service in terms of safety and
mobility performance for the movement of people and goods. Full control of access along the
freeway mainline and ramps, along with control of access on the local roadway network within
the interchange functional area, is critical to providing such service. Therefore, decisions to
approve new or revised interchange access points on Washington’s freeways depend on
consistent application of procedures, analysis, and supporting documentation.

In May 2017, the Federal Highway Administration (FHWA) significantly revised its access policy.
In the memorandum transmitting the new policy to the FHWA Division Administrators, FHWA
states:

“The FHWA has identified several areas where the current Policy may be streamlined to
eliminate duplication with other project reviews. The new Policy will now focus on the
technical feasibility of any proposed change in access in support of FHWA's
determination of safety, operational, and engineering acceptability. Consideration of
the social, economic, and environmental impacts and planning considerations will be
addressed through the National Environmental Policy Act (NEPA) review of the project.
This change will eliminate the potential for duplicative analysis of those issues in the
State DOT's Interstate Access report and the NEPA documentation. The change will
allow State DOTs to submit only a single technical report describing the types and
results of technical analyses conducted to show that the change in access will not have
significant negative impact on the safety and operations of the Interstate System.”

The federal policy change points to a clear link between the NEPA and access revision processes.
The NEPA process will account for the social, economic, and environmental impacts and a
technical report herein called the Access Revision Report (ARR) will account for the safety and
operational impacts.

550.02 Freeway Access Policy

Federal law requires FHWA approval of all access revisions to the Interstate system. Both FHWA
and WSDOT policy require the formal submission of a request to either add, revise, or abandon
access to freeways. FHWA and WSDOT freeway access policies also require proposed access
changes be consistent with the vision, goals, and long-range transportation plans of a
metropolitan area, region, and state.

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Interstate freeways: New or revised access to Interstate freeways requires collaboration with
and approval from FHWA. WSDOT and local partners need to include FHWA from the beginning
of the planning process throughout the development of the proposal. WSDOT is the only entity
recognized by FHWA Washington Division that is allowed to submit requests for Interstate
access revisions for review and approval.

Non-Interstate freeways: New or revised access to non-Interstate freeways requires

engagement with and approval from WSDOT.

For consistency in analysis and reporting, the policy to revise freeway access is the same for
both Interstate and non-Interstate freeways. The only major difference is in the approving
authorities, described above. Exhibit 550-4 helps clarify what is considered an access revision
and presents approval authorities for both Interstate and non-Interstate access revisions.

The contents of this chapter provides the requirements and expectations to fulfill this policy.

Note: For breaks in freeway limited access that do not involve new, revised, or abandoned
traffic interchanges, follow procedures given in Chapter 530 Limited Access Control. Examples
include locked gates, pedestrian structures, and access to fire hydrants within the full control
limited access. Contact the HQ Design Office, Access and Hearings Section for support.

550.03 Access Revision Process

The access revision process begins when an entity considers the potential of revising access to a
freeway (Interstate or non-Interstate). There are two distinct steps in the access revision
process: a non-access feasibility study and an Access Revision Report. Both steps focus on safety
performance and operations for all modes. The feasibility study is the beginning of the process
and the conclusion of the feasibility study defines the purpose and verifies the need for a
potential access revision. If the feasibility study concludes that an access revision is not
necessary, the process is finished. If the feasibility study concludes that an access revision is
necessary, then an Access Revision Report is written and the conclusion of the ARR determines
the preferred access revision alternative. These two steps are detailed in the subsequent
sections of this chapter. Exhibit 550-1 presents a flow chart detailing the Non-Access Feasibility
Study process; Exhibit 550-2 provides the ARR process.

For the process to be successful, there needs to be a clear link to the planning and
environmental processes. The planning linkage should be addressed at the beginning of the
process to make sure the access revision decision aligns with local, regional, and state planning
efforts. This planning linkage is discussed in more detail in Section 550.05(2)(a). The
environmental linkage exists throughout the process as the Federal policy promotes a more
direct link between this access revision process and the environmental process. This chapter
includes callouts to the environmental process at key points to highlight this linkage and to help
align the processes and reduce duplication between the two processes.

The access revision and practical design processes correlate through the use of the Context and
Modal Accommodation Report (CMAR) and the Basis of Design (BOD). The CMAR can help
determine modal priority and accommodation on non-freeway segments, such as the crossroad
proposed for the freeway access connection. The CMAR may be completed during the feasibility
study. The BOD can help document baseline and contextual needs and set the direction for a
future project. Sections 1 through 3 of the BOD (Project Need, Context, and Design Controls)
may be completed at the end of the Non-Access Feasibility Study. Sections 4 and 5 (Alternatives

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Analysis and Design Element Selection) of the BOD should be completed in conjunction with the
ARR. The BOD completed with the ARR may be considered the scoping BOD.

Use the Design Support website to download the CMAR, the CMAR learners Guide, the Basis of
Design and Alternatives Comparison Table. http://www.wsdot.wa.gov/Design/Support.htm

550.03(1) Scalability
The access revision process varies greatly due to the complexities of the transportation system
and context environment planned for the horizon year (see Chapter 1103). Not all access
revision cases require a full-scale ARR. Exhibit 550-4 reflects the access revision documentation
levels for select project types. For variation from Exhibit 550-4 or clarification on scalability,
discuss with the Assistant State Design Engineer (ASDE). Document the scalability in the method
and assumptions documents.

550.03(2) Environmental Documentation Linkage

Implement Planning and Environmental Linkage (PEL) principles during the access revision
process to minimize rework in the environmental review/NEPA stage of the project. Using the
PEL approach is most valuable where an Environmental Assessment (EA) or Environmental
Impact Statement (EIS) is required. Chapter 200 of the Environmental Manual details this
beneficial link between planning and environmental processes.

The new FHWA policy states clearly that the environmental documentation and access revision
processes be linked and aligned to reduce duplication of effort. Throughout this access revision
analysis process, key points correlate with the environmental process. For best results, make
sure the environmental staff is fully engaged and involved in the process. Region Environmental
staff will help determine the best NEPA / SEPA compliance strategy. The team, including FHWA,
determines the type of environmental document required during
the feasibility phase of access review. Since FHWA approval of
Interstate access revisions entails a federal action, National Best Practice: Engage
Environmental Policy Act (NEPA) requirements apply to Interstate
access reviews. If NEPA does not apply to a freeway access WSDOT Environmental
revision, environmental documentation through the State experts to determine
Environmental Policy Act (SEPA) does apply. In either case, the NEPA / SEPA strategy.
team, comprised of experts and agents from WSDOT and FHWA,
is authorized to determine the type of environmental
documentation required.

If the team determines the project can be documented as a Categorical Exclusion/ Exemption
(CE), involvement from environmental staff at key decision points will help ensure the project is
appropriately scoped and environmental considerations are integrated into the ARR as
appropriate. For a CE, information from the Non-Access Feasibility Study can be useful, but is
typically much more detailed than the information required for the CE checklist.

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550.04 Support Teams

550.04(1) Executive Support Team

Establish an executive support team before beginning the feasibility study. The executive
support team is active throughout the access revision process. Their primary duty is to interpret
policy and set direction for their representatives involved in the technical support team. The
representatives will be signees on the deliverables that are required throughout this chapter.
The executive support team meets to monitor the progress of the deliverables and prepares
records of meeting minutes and decisions.

Due to the scalability of the process, the executive support team can vary with each access
revision case but will typically have a core of the following individuals:
 FHWA Safety and Geometric Design Engineer
 Region Representatives (Assistant Regional Administer, Traffic Engineer, Local
Programs Engineer, Environmental Manager, and/or Planning Manager)
 Assistant State Design Engineer
 HQ Traffic
 Local agency representatives (city, county, port, transit and/or tribal government)

550.04(2) Technical Support Team

The technical support team conducts a majority of the detailed analyses required throughout
the access revision process. This team meets regularly to ensure deliverables and project details
are coordinated across disciplines. A subgroup of the technical team may also conduct separate
meetings to coordinate specific details. The technical team delivers results and conclusions of
their work back to the executive support team for review and approval. The technical group
records and tracks meeting minutes and action items.

Due to the scalability of the process, the technical support team can vary with each access
revision case. Work with the executive support team to make sure the right personnel are on
the team. The team members may include representation from the following groups:
 Planning organization (Metropolitan Planning Organization (MPO) and/or Regional
Transportation Planning Organization (RTPO))
 FHWA (Area Engineer, Environmental Program Manager, and/or ITS Engineer)
 WSDOT Region (planning, design, environmental, maintenance, and/or traffic)
 WSDOT HQ Multimodal Development & Delivery
 Local agency specialist (planning, developer services, public works, and/or engineering)
 Project proponents specialists (developer and/or consultant)
 Multimodal specialist (transit, bike, and/or pedestrian)
 Other identified stakeholders/partners

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550.05 Non-Access Feasibility Study Process

The goal of this first step in the access revision process is to look at the non-access
transportation network to determine if improvements can be made that address performance
gaps for all modes. Non-access improvements are solutions that do not impact the gore points
to/from the mainline of the freeway. Examples are changes to the local street network, travel
demand management, traffic operations enhancements, crossroads, ramp meters, minor
geometric ramp modifications, transit, and minor ramp terminal
modifications.
Performance Gap – The
The Non-Access Feasibility Study is a multistep process and begins
(see Exhibit 550-1) with assembling an executive support team. The difference between the
WSDOT Region assembles the executive support team. The measured and targeted
executive support team convenes and the local, regional, tribal, or performance unit for a
state entity that is the proponent of the access revision presents
performance metric. See
the performance gaps that represent the probable baseline needs
for an access revision. If the executive support team agrees there is 1100 Series Chapters.
a probable performance gap that needs further study, then the
technical support team is formed. The technical support team
develops the draft purpose and need and the process of conducting a non-access feasibility
study begins and a method and assumptions (M&A) document is prepared.

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Freeway Access Revision Chapter 550

Exhibit 550-1 Non-Access Feasibility Study Process

Feasibility Study Trigger:

New or revised freeway access is
under consideration [see 550.03]

Establish Support Teams

[see 550.04]

Executive Team
Agrees There Is a
Identify transportation performance gaps and Gap No
develop draft purpose and need [see 550.05]

Yes
Stop Study
Plannaing and Environmental Linkages (PEL) [see 550.03(2)]

ü Signature Page
ü Establish study purpose
Prepare Feasibility Study ü Establish Team roles and
NEPA/SEPA Process [see 550.03(2); 550.05(1); 550.05(2)(f)

Methods and Assumptions responsibilities

Document [see 550.05] ü Establish study area
ü Establish tools to be used
ü Establish measures of effectiveness
ü Etc.
Evaluate local system
improvements [see 550.05(2)]

Solution found that

Prepare Feasibility Report does not revise
freeway access?

Yes

Conclude Feasibility Study: Stop the Study:

No No revised or added
Define Project Need
access to state system
allowed [see
550.05(2)(e)

Proceed with non-freeway

solution

Note: Some alternatives

See Exhibit 550-2 for Access identified in the Feasibility Study
Revision Process may be carried forward into the
ARR for further consideration

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Linking to the state and local planning representatives is

essential. It is possible that a local planning study has been
conducted that meets the requirements of the non-access Planning Linkage – The
feasibility study. If this is the case, the executive support team best projects consider
can make the determination that the planning study is and complement local,
sufficient and move on to the ARR. It is necessary to also regional, and state
coordinate with the region’s environmental representative to
help ensure the local planning study is sufficient in developing transportation plans for
the purpose and need necessary for the environmental all modes.
process.

550.05(1) Non-Access Feasibility Study Methods and Assumptions

Document
The next step in a Non-Access Feasibility Study is to create a methods and assumptions (M&A)
document that establishes the methods followed while the study is being conducted and the
assumptions made during the study. Cover the following points in the M&A document:
 Team Participants
Executive team members, roles, and responsibilities
Technical team members, roles, and responsibilities
 Scalability (if applicable, see Section 550.03(1) and Exhibit 550-4)
 Planning Linkage
Pertinent planning documents
Prior community engagement
 Environmental Linkage
Probable environmental documentation: EIS, EA, or CE
NEPA/SEPA compliance strategy
 Community Engagement
See Community Engagement Plan
• Alternatives Selection
Process for determining non-access reasonable alternatives including alternative
development and screening
Traffic Operational Analysis Scope and Scale
Determine the study area for operational analysis. For efficiency and uniformity
of data, it may be beneficial to assume a freeway access revision will be
necessary when determining the study area. Discuss the study area in detail,
reach agreement on its scope and scale, and record in the M&A document.
Typical analysis study areas include:
 Particularly in urbanized areas, at least the first adjacent existing or proposed
interchange on either side of where an access revision is being considered and the
entire freeway components within this area.
 The crossroads to at least the first major intersection on either side of where the
access revision is being considered. The local street network should be extended as
necessary to fully evaluate the impacts of the proposed change in access.

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Freeway Access Revision Chapter 550

 Incorporate connections to the transit network inside the study area as

modifications to the transit service may impact travel demand.
 Incorporate regional trails/pathways inside the study area as improving multimodal
connectivity may impact travel demand.
Study period: AM/PM Peak, midday, weekends
Study years: Current, opening, design/horizon
Methodology: Highway Capacity Manual or other tool
Multimodal priorities and accommodation
 Transit operations and considerations: Transit must be given consideration in
locations where freeways are at capacity in the peak hours.
 Bicyclist networks connectivity, needs, considerations.
 Pedestrian access and network connectivity, needs, considerations.
Tools: Software versions and default software settings
Traffic forecasting methodology:
Measures of effectiveness
 Safety Performance Analysis Scope and Scale (See Chapter 321)
Study area
Study period
Study years: Current, opening, design/horizon
Methodology
Tools
Measures of effectiveness
 Identify and Record Assumptions
Base Improvements – Transportation projects that will be built by developers,
local agencies, and the state and what year they will be built.
Items that are uncertain and may have an impact on the analysis. For example
funding, tolling, context changes, modal shift, or travel demand management.
 Change Management
How will your study address changes in assumptions, scope, or deliverables?

The above list is not all-encompassing nor is everything in the list covered in every study. The
technical support team refines the above list as necessary and submits the outline of the
feasibility study to the executive support team for concurrence.

The Non-Access Feasibility Study M&A document contains a signature page for concurrence by
the executive support team. A template for the M&A document is here:
http://www.wsdot.wa.gov/design/accessandhearings

The Non-Access Feasibility Study may begin upon concurrence of the M&A document.

550.05(2) Non-Access Feasibility Study

Conduct and document the non-access feasibility study following the assumptions and guidance
set forth in the M&A document. This determines whether non-access improvements can
address the performance gaps agreed upon by the executive support team. The Non-Access
Feasibility Study contains the following items:
 Signature Page

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Chapter 550 Freeway Access Revision

 Project Background
 Vicinity Map
Study Area
 Planning Linkage (see Chapter 550.05(2)(a))
Multimodal Needs
 Traffic Volumes (see Chapter 550.05(2)(b))
 Traffic Operational Analysis (see Chapter 550.05(2)(c))
 Safety Performance Analysis (see Chapter 550.05(2)(d))
 Reasonable Non-Access Alternatives (see Chapter 550.05(2)(e))
 Conclusion (see Chapter 550.05(2)(f))
Purpose and Need for Access Revision

Non-Access Feasibility Study is compiled and reviewed first by the technical support team prior
to being sent to the executive support team for signature. If the process does not go into the
ARR phase, then send a final copy of the Non-Access Feasibility Report to your ASDE for filing. If
the process continues into the ARR phase, then attach the Non-Access Feasibility Report to the
ARR as an appendix.
550.05(2)(a) Planning Linkage

It is essential to create the linkage to the transportation planning processes and outputs by the
WSDOT and other agencies in the non-access feasibility study. Any transportation improvement
considered in the access revision process should align with these planning processes. Describe
how the improvements are consistent with local land use plans, and local, regional, and state
transportation plans including possible future interchanges, bicyclist/pedestrian networks,
transit service, and possible development.

While the need for freeway access is motor vehicle based, it is also
important to address the needs of all modes that will access and use Consistent and
the local networks and freeway crossroad(s). An important aspect of
purposeful
the planning linkage is to address multimodal connectivity on the
crossroad. While interchange crossroads may provide vehicle access planning linkages
to and from the freeway mainline, they also provide critical between agency
multimodal connectivity between land uses on either side of the partners helps the
freeway. Consult comprehensive land use and transportation plans for
process.
multimodal elements. Document multimodal needs, priority, and
accommodation in the Non-Access Feasibility Study.

A non-access feasibility study may be performed in conjunction with

another planning process. When a non-access feasibility study is performed in conjunction with
another planning process, then that process must address the requirements for a non-access
feasibility study in addition to requirements of other planning processes. Include WSDOT
Planning and local agency staff (land use and transportation planning specialties) in the technical
support team to determine if this linkage is possible or beneficial.

If another planning process or study appears to meet the requirements of the Non-Access
Feasibility Study, have the technical support team review it and determine if it is applicable. If
the technical team finds the process or study meets the requirements of the feasibility study,
then present it to the executive support team and request an exemption from the feasibility

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study process. Clearly document this exemption and receive written approval from the
members of the executive support team.
550.05(2)(b) Traffic Volumes

Traffic volumes for the existing, opening, design, and horizon year are determined and reported
in the feasibility study. It is important to consider pedestrian, bicyclist, and transit volumes
where applicable. The existing year is the year the traffic data is collected. Consult Chapter 1103
for definitions and details of opening, design, and horizon years.

The data for the future years may come from a regional transportation model or linear
projections unique to the study. Exponential growth projections are not recommended.

Regional transportation models may also be used for the opening and design year volumes.
Transportation models are commonly maintained by a Metropolitan Planning Organization.
These models predict traffic volumes by dividing the area into zones, populating these zones
with the appropriate type of land use, and predicting travel demand on the road network based
upon the trip demand and travel time between destinations. The process to develop these
models is extensive; therefore, the models are not continuously updated. Opening/design years
that do not correlate with the years of the regional transportation model may be adjusted by a
linear growth rate to the opening/design year of the traffic study. The technical support team
determines how to best use an available model. Document the model used, how the model was
calibrated and validated.

Traffic models used for the ARR process should incorporate transit, bicyclists, and pedestrians.
If the model does not have the ability to incorporate these other modes, investigate the viability
of modifying link and intra-zone trips with the technical support team to reflect the multimodal
trips. Consider how changing access to these other modes may impact travel demand within
and through the study area.

If linear projections are used, be careful to not base projection on a valley or peak in historic
traffic volumes. Record any assumptions applied to linear projections in the feasibility study.

550.05(2)(c) Operational Analysis

Conduct the operational analysis over the study area, using the tools and methodology in
accordance with the M&A document. Conduct the operational analysis on the opening and
design year. The technical support team determines if it is necessary to have existing year
analysis or if the no-build at opening year is sufficient. For these years:
 Conduct the Existing operational analysis over the study area (if required by the
technical support team)
No change in the existing roadway network.
Use the existing traffic volumes and calibrate to existing conditions to determine
if the analysis reflects existing conditions and the model is validated.
 Conduct Base Improvements operational analysis over the study area
The existing roadway network with the addition of local or non-access
transportation projects and services that are funded for construction/delivery or
have a high likelihood of being constructed/delivered, as identified as base
network improvements in the M&A document. Incorporate base network
improvements into the analysis.

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The result of this base improvements operational analysis is a list of the locations
where the transportation system has potential performance gaps. Compare this
list of locations to the performance gaps identified in the beginning of the access
revision process. The analysis helps clarify whether or not performance gaps
exist. Identify these gaps in the report. These identified gaps will be where the
technical support team focuses in the operational analysis done for the
reasonable non-access alternatives. This leads to identification of performance
targets by mode.
 Conduct the Build operational analysis over the study area
Incorporate the base improvements as the starting point, then evaluate
reasonable non-access alternatives as discussed in 550.05(2)(e)
The build operational analysis assess whether the non-access alternatives
address the identified performance gaps.
550.05(2)(d) Safety Analysis

Conduct a safety analysis per Chapter 321.04 and Section 8.1 of the Safety Analysis Guide. In
this section of the feasibility study, discuss the safety performance of the existing transportation
network. For the non-access Feasibility Study, the safety analysis needs to focus on the non-
access network; safety analysis of the freeway mainline is not required.
550.05(2)(e) Reasonable Non-Access Alternatives

The Non-Access Feasibility Study must look at reasonable alternatives that can address the
performance gaps noted in the operational analysis and/or safety performance analysis. The
determination of reasonable alternatives follows the process as noted in Chapter 400.07(1)4 of
the WSDOT Environmental Manual. Each reasonable alternative must consider the change in
safety performance per the Safety Analysis Guide.

The goal of the alternatives is to identify non-access improvements and performance targets
that address operation gaps and safety performance
characteristics for all modes. Alternatives should first
consider non-access, operational and/or demand Performance target – an
management improvements. Coordinate these outcome or desired state
improvements with local and state planning staff. The intended for a part of the
technical support team initiates alternatives for
consideration and presents them to the executive support system.
team for approval. Include alternatives comprised of See Chapter 1101.
varying types such as intersection solutions, corridor
solutions, land use modifications, transit improvements,
mode shift, travel demand management or other systematic network-based Practical Solutions
approaches. Use the measures of effectiveness discussed in the methods and assumptions
document to compare alternatives.

Provide a list of non-access improvements needed to address the performance gaps. If an

improvement will be within the state’s jurisdiction, then complete a scoping Basis of Design for
this improvement and include as an appendix to the feasibility study. If the non-access
improvements can address the performance gaps within the criteria defined in the M&A, then
state such in this section and conclude the access revision process.

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If the non-access improvements do not completely address the performance gaps, but do show
value, then they should be carried forward into the access revision analysis for further inclusion
in the project.
550.05(2)(f) Non-Access Conclusion

If the non-access improvements can address the performance gaps within the criteria defined in
the M&A, then state such in this section and conclude the access revision process.

If the feasibility study indicates that addressing performance gaps cannot be reasonably
achieved without revising freeway access, then write a purpose and need for access revision in
this section of the feasibility study. This purpose and need statement should be written in close
coordination with the Environmental Office as this is a key linkage point between the
NEPA/SEPA process and the access revision process. The goal of this section is to provide a
purpose and need statement that can be used for the Access Revision Report, a Basis of Design
for an access revision, and the NEPA/SEPA process.

In addition to the purpose and needs statement, summarize the non-access alternatives that are
needed and carried this list forward into the ARR.

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550.06 Access Revision Report Process

In order to approve or reject a proposed revision to freeway access, specific analyses are to be
completed and then documented in a technical report. This report is the Access Revision Report
(ARR), previously known as an Interchange Justification Report (IJR). The proponents, with the
help of the support team, prepares the ARR. One of the first steps should be the formation of
the Executive Support Team. See section 550.04. Next develop a methods and assumptions
document as outlined in section 550.05(2). The M&A document will be used to analyze the
access revision and assist in developing the Access Revision Report.

Exhibit 550-2 Access Revision Report Process

From Exhibit 550-1

Established Teams continue

[See 550.04]

Develop Methods and Assumptions Note: Feasibility Study M&A

document for ARR [see 550.06(1)] modified as necessary for the
ARR
NEPA / SEPA Process Continues to completion

Conduct ARR [see 550.06(2)]

Access Process Ends with

revision No
acceptable? no access revision

Yes
Finding of Engineering
and Operational
Acceptability
granted while NEPA /
NEPA / SEPA SEPA
is being completed. No
complete?
Interstates: FHWA
Non-interstates:
WSDOT
[see 550.06(3)]

NEPA / Yes
SEPA
completed
[550.06(3)]

Combine NEPA / SEPA

Return ARR to Document and ARR
[550.06(3)]
FHWA for final
acceptance

Access Revision Approved

[550.06.(3)]

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550.06(1) Access Revision Report Method and Assumptions Document

Begin by reevaluating the Non-Access Feasibility Study M&A to determine if it is applicable to
the ARR. Pay attention to the sections on alternatives selection and assumptions. These two
sections will likely change between the feasibility and the ARR phases. If there is no change, the
Non-Access Feasibility M&A may be adopted by the executive committee. If a modification of
the M&A is necessary, the executive committee has the ability to require a full rewrite or to
agree to a scaled down effort for the ARR. If a full rewrite is necessary, follow the same outline
as presented in Section 550.05(1) with the addition of allowing on-system improvements.

550.06(2) Access Revision Report

The Access Revision Report addresses:
1. Reasonable Alternatives; see 550.06(2)(a)
2. Operational Analysis; see 550.06(2)(b)
3. Safety Performance Analysis; see 550.06(2)(c)
4. Conceptual Signing Plan; see 550.06(2)(d)

The following provides details for completing the Access Revision Report.

550.06(2)(a) ARR Reasonable Alternatives

Consider alternatives in the Non-Access Feasibility Study that are carried forward into the ARR
process and any new alternatives that may be developed for on-system alternatives. Then
narrow the alternatives down to a few reasonable alternatives that will go through the
evaluation process. Determine the reasonable alternatives for the ARR phase near the beginning
of the process. This is necessary because the alternatives will set the course for the operational
and safety analysis and determine exactly what must be analyzed.

The technical team evaluates each reasonable alternative with respect to operations and safety
performance for all modes (see Section 550.06(2)(b) and (c)). Alternatives are refined based
upon the results of the analysis and then presented to the executive support team for
acceptance.

Conduct the alternatives selection and analysis process within the ARR with full consideration of
the environmental process and environmental documentation that will be required. The ARR
must be fully compatible with the corresponding environmental process. Include Region
environmental staff in the alternatives selection process.

In the ARR document, include a description of the reasonable alternatives identified for
consideration. At this point, you should have a few reasonable alternatives that will be carried
forward through the whole ARR process and will have detailed operations and safety analysis
conducted (see Section 550.06(2)(b) and (c)). The results of this analysis will be used to
compare the alternatives and ultimately reach a preferred alternative. To document the
evaluation criteria and the results of the analysis, use the Alternatives Comparison Table (ACT)
or a similar tool.

Public Road Connection

The ARR must show that the proposed access will connect to a public road network.

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Less than “full interchanges” may be considered on a case-by-case basis for applications
requiring special access, such as managed lanes (e.g., transit or high occupancy vehicle and high
occupancy toll lanes) or park and ride lots.

In other cases where all basic movements are not provided by the proposed design, the ARR
typically includes a full interchange option with a comparison of the operational and safety
performance analyses to the partial-interchange option. The ARR should also include the
mitigation proposed to compensate for the missing movements, including wayfinding signage,
impacts on local intersections, mitigation of driver expectation leading to wrong-way
movements on ramps, etc. The ARR should demonstrate that the future provision of a full
interchange is not precluded by the proposal or describe how that future decision will be
accommodated.

The crossroad must address the needs of all modes that are supported by the land use and
demographics of the area. While the needs and priority of multimodal users are identified in the
feasibility study, the ARR helps ensure multimodal needs are incorporated in the design.

Design Standards and Criteria

FHWA policy requires that AASHTO Interstate standards (A Policy on Design Standards –
Interstate System, AASHTO, latest edition) are used. This Design Manual provides criteria to
meet FHWA and WSDOT policy on geometric standards. To achieve design standards
requirements, apply the criteria in these key Design Manual Chapters:
 Chapters 1100 – 1106 for an overview of practical design procedures, development of
need statements, procedures for selecting appropriate multimodal design controls and
design element dimensions. Assume the crossroad design will have implications and
effects on all travel modes legally allowed. Provide obvious traffic control for all modes.
 Chapters in the 1200 series provide geometrics including plan and profile elements and
freeway and other roadway type cross section criteria. Chapter 1232 provides
geometric cross section dimensions for Interstate and non-Interstate freeways. Other
chapters in this series provide cross section criteria for roadway types which could
apply to multimodal crossroads and local street or roadway contexts.
 Chapters in the 1300 series provide design criteria for Interchange spacing and design,
and procedures for evaluating intersection control types. Chapters 1300 - Intersection
Control Type and 1360 - Interchanges
 For special interchanges for HOV or Transit, see chapters in the 1400 series.
 Chapters in the 1500 series provide design guidance for pedestrian and bicyclist
facilities.
 See other chapters as applicable for various aspects of design and approvals.

550.06(2)(b) ARR Operational Analysis

The operational analysis for the ARR builds upon the operational analysis from the feasibility
study. If demonstrated in the feasibility study that local solutions will not completely satisfy the
Purpose and Need, the scope of the ARR operational analysis includes reasonable alternatives
that consider revisions in freeway access as well as non-access improvements that are carried
forward from the Non-Access Feasibility Study. This analysis must conclude that the proposed
change in access does not have a significant adverse impact on the safety and operation of the

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freeway facility or on the local street network for all modes, based on both current and planned
future traffic projections. The freeway facility includes the main line lanes, collector-distributor
lanes, existing, new, or modified ramps, and ramp intersections with crossroad.

The following are typical requirements for the analysis. The technical support team makes the
ultimate decisions on transportation operational and safety performance analysis requirements.
However, FHWA policy suggests the following expectations.
 The analysis includes, particularly in urbanized areas, a minimum of the first adjacent
existing or proposed interchange on either side of the proposed change in access.
 The crossroads and the local street network, to a minimum of the first major
intersection on either side of the proposed change in access, should be included in this
analysis to the extent necessary to fully evaluate the safety performance and
operational impacts that the proposed change in access and other transportation
improvements may have on the local street network.
 The requested proposed change in access should include a description and assessment
of the impacts and ability of the proposed changes to collect, distribute, and
accommodate traffic on the Interstate facility, ramps, intersection of ramps with
crossroad, and local street network.

Intersection Control Evaluation

The Access Revision Report also includes fulfilling the requirements of the Intersection Control
Evaluation (ICE) to verify the chosen intersection(s) control at the interchange are adequate for
all modes. An ICE will not be required if the ARR documents the criteria required for an ICE. See
Chapter 1300 for ICE instruction.

550.06(2)(c) ARR Safety Analysis

Conduct a safety performance analysis per Chapter 321 and Section 8.1 of the Safety Analysis
Guide. For the ARR, discuss the safety performance of the reasonable alternatives. Use the
results of the safety performance analysis to compare alternatives.

550.06(2)(d) ARR Signing Plan

Include a conceptual plan of the type and location of the signs proposed for the preferred
alternative to support the Access Revision Report. The conceptual plan is typically limited to
guide signage, but regulatory or warning signs may be required if the interchange configuration
is unusual.

550.06(3) Access Revision Report Review and Approval

Exhibit 550-3 provides a template for approvals and concurrence signatures.

Draft ARR review: The draft ARR is first reviewed by the executive and technical support teams.
After their review, the Region submits an electronic copy (in PDF format), including appendices,
to the ASDE along with a cover memo requesting review. The ASDE responds in writing either
with needed revisions or to request the final draft.

Final ARR Submittal: For final submittal, send the final ARR in PDF format to the ASDE. Contact
the ASDE for the necessary number of hard copies. The Region submits a memo to the

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appropriate ASDE, requesting final approval of the ARR. After ASDE concurrence, the ASDE
submits Interstate ARRs to FHWA for approval.

ARR Approvals can be a two-step process:

 If environmental documentation is not complete, teams can request a finding of
engineering and operational acceptability. FHWA grants this for Interstate access
revisions and WSDOT grants for non-interstate.
 If the environmental documentation is complete, teams request final ARR approval.

Interstate Approval Notes:

 Interstate Access Revision Reports are most often reviewed and approved by the
Washington FHWA Division Office. A 30-day review period must be allowed for the
FHWA Division Office. Occasionally they are sent to FHWA Headquarters Office in
Washington, DC (see Exhibit 550-4). If this is the case, additional review time is
necessary.

FHWA provides final approval of the Interstate ARR when the appropriate final environmental
document is complete: CE, FONSI, or ROD. The intent of the federal policy is to create a clear
link between the ARR and NEPA processes. The ARR may be used as the transportation discipline
report for an EIS/EA or included as an attachment to a CE. Coordinate with the Region
Environmental Staff to integrate the ARR with the environmental documentation.

WSDOT provides final approval of the non-Interstate ARR when the appropriate final
environmental document is complete.

550.06(4) Updating the Access Revision Report

The period between the approval of the Access Revision Report, completion of the
environmental documentation, and the construction contract commonly spans several years. If
the period exceeds three years, the approved ARR must be reviewed to identify changes that
may have occurred during this period. If there have been little or no changes, an extension of
the period may be granted. In this case, write a summary assessment for approval by the Region
Traffic Engineer, ASDE, and FHWA.

If no work has begun within three years of completion of the environmental documentation, a
re-evaluation of the CE/EA/EIS may be required (see Environmental Manual 400.06(1)). Contact
the Region Environmental Office to determine if the environmental documentation must be re-
evaluated.

550.07 Documentation
This chapter discusses in detail the requirements for the following documents:
 Non-Access Feasibility Study Method and Assumptions
 Non-Access Feasibility Study
 Access Revision Report Method and Assumptions
 Access Revision Report

For levels of approval for each of these documents, refer to Exhibit 550-4 and Chapter 300.

The final Access Revision Report is archived by the HQ Access and Hearings Section.

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Freeway Access Revision Chapter 550

550.08 References

550.08(1) Federal/State Laws and Codes

23 Code of Federal Regulations (CFR) Part 450 (implementing 23 United States Code [USC]
Section 135)

40 CFR Parts 51 and 93 (regarding federal conformity with state and federal air quality
implementation plans)

23 USC Sections 111 (requires the U.S. Secretary of Transportation to approve access revisions
to the Interstate System), 134 (metropolitan transportation planning), and 135 (statewide
transportation planning)

FHWA Interstate Access Policy, update May 22, 2017.

https://www.fhwa.dot.gov/programadmin/fraccess.cfm

550.08(2) Design Criteria and Supporting Information

Design Manual, Chapter 320, Traffic Analysis

Design Manual, Chapter 321, Sustainable Safety

Environmental Manual, Chapter 200, Planning

Environmental Manual, Chapter 400, NEPA/SEPA

WSDOT, NEPA/SEPA Guidance:

http://www.wsdot.wa.gov/Environment/Compliance/default.htm

Safety Analysis Guide, WSDOT; See Sustainable Highway Safety Tools here:
http://www.wsdot.wa.gov/Design/Support.htm

WSDOT Design support http://www.wsdot.wa.gov/Design/Support.htm

Use the Design Support website to download the Context and Modal Accommodation report,
Basis of Design, and Alternatives Comparison Table.

WSDOT Planning: find resources including Corridor Sketch Initiative, Corridor Planning Studies,
links to the Highway System Plan, and other supporting information.
http://www.wsdot.wa.gov/planning/default.htm

WSDOT Transportation Corridor Planning Studies

https://www.wsdot.wa.gov/publications/manuals/fulltext/M3033/PSGC.pdf

WSDOT HQ Access and Hearings (including Freeway Access Revisions Resource Document)
www.wsdot.wa.gov/design/accessandhearings

FHWA Traffic Analysis Toolbox (tools used in support of traffic operations analyses)
www.ops.fhwa.dot.gov/trafficanalysistools/index.htm

FHWA Environmental Review Toolkit

https://www.environment.fhwa.dot.gov/default.aspx

Highway Capacity Manual, (HCM) 2010, Transportation Research Council

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Chapter 550 Freeway Access Revision

Highway Safety Manual (HSM), AASHTO, 2010

Local Agency Guidelines (LAG), M 36-63, WSDOT

NEPA Categorical Exclusions A Guidebook for Local Agencies, WSDOT

WSDOT Design Manual M 22-01.15 Page 550-19

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Freeway Access Revision Chapter 550

Exhibit 550-3 Access Revision Report: Stamped Cover Sheet Example

Access Revision Report “Title”

“MP to MP”
This Access Revision Report has been prepared under my direct supervision, in accordance with Chapter 18.43
RCW and appropriate Washington State Department of Transportation manuals.

ARR Engineer of Record

By:__________________________________________ P.E.

Date:________________________________________

Traffic Analysis Engineer

By:________________________________________ P.E.

Date:______________________________________

By:________________________________________ P.E.
WSDOT Approval –
Assistant State Design Engineer
Date:______________________________________

FHWA Approval –
FHWA Safety and Design Engineer
By:________________________________________
Date:______________________________________

Concurrence –
Region Traffic Engineer
By:________________________________________ P.E.

Date:______________________________________

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 Chapter 550 Freeway Access Revision

Exhibit 550-4 Access Revision Documentation and Review/Approval Levels

Required Non-
Support Interstate
Project Type Documentation Interstate
Team
NAFS* ARR* Concurrence Approval HQ
FHWA and
New freeway-to-freeway interchange Yes ü ü FHWA DC Approval
HQ
Revision to freeway-to-freeway interchange FHWA and
Yes ü ü FHWA DC Approval
in a Transportation Management Area[1][2] HQ
FHWA and
New partial interchange Yes ü ü FHWA DC Approval
HQ
New freeway-to-crossroad interchange Yes ü ü HQ FHWA Approval
Revision to freeway-to-freeway interchange
not in a Transportation Management Yes ü ü HQ FHWA Approval
Area[2]
Revision to freeway-to-crossroad
interchange, including but not limited to:[2]
1. Adding entrance or exit ramps that
complete basic movements
2. Changing I/C configuration (e.g. Yes ü ü [4] HQ FHWA Approval
diamond to SPUI, DDI, etc.)
3. Adding loop ramp to existing diamond
4. Adding on-ramp lanes that increase
mainline entry point(s)
Revision to freeway-to-crossroad
interchange, including but not limited to: [3]
HQ and
1. Intersection control at ramp terminal(s) No [5]
ü [4] Approval
FHWA
2. Adding lanes to on-ramps/off-ramps
without revising the entry/exit points
New HOV direct access Yes ü ü HQ FHWA Approval

HQ and
Transit flyer stop on main line No [5] ü [4] Concurrence
FHWA
HQ and
Transit flyer stop on a ramp No [5] ü [4] Concurrence
FHWA
Abandonment of a ramp No [5] ü [4] HQ FHWA Concurrence
Locked gate
Access breaks that do not allow any type of
access to main line or ramps (i.e. access
doors in noise walls, gates to storm water
retention/detention facilities from outside See Chapter 530
limited access, etc.)
Structure over or under with no ramps
(including pedestrian, bike, or trail)
Construction/emergency access break
* NAFS = Non-Access Feasibility Study, ARR = Access Revision Report. For notes, see next page.

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Freeway Access Revision Chapter 550

Exhibit 550-4 (cont.) Access Revision Documentation and Review/Approval Levels

Notes:

[1] Washington Transportation Management Areas include Southwest Washington Regional

Transportation Council (RTC) (Clark County), Puget Sound Regional Council (PSRC) (King, Kitsap,
Pierce, and Snohomish Counties), and Spokane Regional Transportation Council (SRTC) (Spokane
County).

[2] “Revision” includes changes in interchange configuration even if the number of access points does
not change. Changing from a cloverleaf to a directional interchange is an example of a “revision.”

[3] “Revision” includes changes that might adversely affect the level of service of the through lanes.
Examples include: doubling lanes for an on-ramp with double entry to the freeway; adding a loop
ramp to an existing diamond interchange; and replacing a diamond ramp with a loop ramp.
Revisions to the ramp terminal intersections may not require an ARR unless the traffic analysis
shows an impact to the main line traffic.

[4] The scale and scope of the access revision dictate the level of effort needed. Consult the Assistant
State Design Engineer (ASDE), Region Traffic, and the FHWA Area Engineer, if applicable, for
direction.

[5] Consult the Region Planning Manager for the status of planning at this location.

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Chapter 560 Fencing
560.01 General
560.02 Design Criteria
560.03 Fencing Types
560.04 Gates
560.05 Procedure
560.06 Documentation
560.07 References

560.01 General
Fencing is provided primarily to discourage encroachment onto Washington State Department
of Transportation (WSDOT) highway right of way from adjacent property, to delineate the right
of way, and to replace fencing that has been disrupted by construction.

Encroachment onto the right of way is discouraged to limit the presence of people and animals
that might disrupt the efficient flow of traffic on the facility. Although not the primary intent,
fencing does provide some separation between people, animals, traffic flow, and other features.

560.02 Design Criteria

560.02(1) General
Fencing on a continuous alignment usually has a pleasing appearance and is the most
economical to construct and maintain. The recommended practice is to locate fencing on or,
depending on the terrain, 12 inches inside the right of way line.

Where the anticipated or existing right of way line has abrupt irregularities over short distances,
coordinate with Maintenance and Real Estate Services personnel to dispose of the irregularities
as excess property (where possible) and fence the final property line in a manner acceptable to
Maintenance.

Whenever possible, preserve the natural assets of the surrounding area and minimize the
number of fence types on any particular project.

560.02(2) Limited Access Highways

On highways with full and partial limited access control, fencing is mandatory unless it has been
established that such fencing may be deferred. Fencing is not required for modified limited
access control areas, but may be installed where appropriate. Fencing is required between
frontage roads and adjacent parking or pedestrian areas (such as rest areas and flyer stops) and
highway lanes or ramps unless other barriers are used to discourage access violations.

On new alignment, fencing is not provided between the frontage road and abutting property
unless the abutting property was enclosed prior to highway construction. Such fencing is
normally part of the right of way negotiation.

Unless there is a possibility of access control violation, fencing installation may be deferred until
needed at the following locations:

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Fencing Chapter 560

 In areas where rough topography or dense vegetation provides a natural barrier.

 Along rivers or other natural bodies of water.
 In sagebrush country that is sparsely settled.
 In areas with high snowfall levels and sparse population.
 On long sections of undeveloped public or private lands not previously fenced.

When in doubt about fencing installation, consult the Headquarters (HQ) Access and Hearings
Manager.

560.02(3) Managed Access Highways

Fencing is not required for managed access highways. When highway construction will destroy
the fence of an abutting property owner (which was originally constructed on private property),
the cost of replacement fencing may be included in the right of way payment. When the fences
of several property owners will be impacted, it may be cost-effective to replace the fences as
part of the project.

If fencing is essential to the safe operation of the highway, it will be constructed and maintained
by the state. An example is the separation of traveled highway lanes from adjacent facilities with
parking or pedestrian areas (such as rest areas and flyer stops).

560.02(4) Special Sites

Fencing may be needed at special sites such as pit sites, stockpiles, borrow areas, and
stormwater detention facilities.

Fencing is not normally installed around stormwater detention ponds. Evaluate the need to
provide fencing around stormwater detention facilities when pedestrians or bicyclists are
frequently present. Document your decision in the Design Documentation Package.

The following conditions suggest a need to evaluate fencing:

 Children or persons with mobility impairments are frequently present in significant
numbers in locations adjacent to the facility, such as routes identified in school walk
route plans or nearby residential areas or parks.
 Water depth reaches or exceeds 12 inches for several days.
 Sideslopes into the facility are steeper than 3H:1V.

Fencing proposed at sites that will be outside WSDOT right of way requires that local ordinances
be followed if they are more stringent than WSDOT’s.

Wetland mitigation sites are not normally fenced. When evaluating fencing for wetland
mitigation sites, balance the need to restrict human access for safety considerations (such as the
presence of children) with the need to provide animal habitat.

Other special sites where fencing may be required are addressed in the following chapters:
 Chapter 720, Bridges (refers to protective screening)
 Chapter 1510, Pedestrian Design Considerations

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Chapter 560 Fencing

 Chapter 1520, Bicycle Facilities

The fencing types and designs for special sites are determined by the requirements of each
situation.

560.03 Fencing Types

560.03(1) Chain Link

Installation of chain link fence is appropriate for maximum protection against right of way
encroachment on sections of high-volume highways in the following locations:
 Along existing business districts adjacent to a freeway.
 Between freeways and adjacent parallel city streets.
 Where existing streets have been cut off by freeway construction.
 In industrial areas.
 At large residential developments.
 On military reservations.
 At schools and colleges.
 In recreational and athletic areas.
 In developed areas at the intersection of two limited access highways.
 At any other location where a barrier is needed to protect against pedestrian, bicyclist,
or livestock encroachment in limited access areas.

For roadway sections in rock cuts, see Chapter 1239.

The Standard Plans contains details for the approved types of chain link fence. The
recommended uses for each type of fence are as follows:
560.03(1)(a) Type 3

This is a high fence for areas of intensified use, such as industrial areas or school playgrounds.
Use this fence for new installations of high fencing. It may be used within the Design Clear Zone.

560.03(1)(b) Type 4

This is a lower fence for special use, such as between the traveled highway lanes and a rest area
or flyer stop or as a rest area boundary fence if required by the development of the surrounding
area. This fence may be used along a bike path or hiking trail to separate it from an adjacent
roadway.

Justify why corrective action is not taken when existing fencing with a rigid top rail will be left in
place within the limits of a proposed project. For cases where a more rigid fence is needed,
contact the HQ Design Office.

Coated galvanized chain link fence is available in various colors and may be considered in areas
where aesthetic considerations are important. Coated ungalvanized chain link fence is not
recommended.

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Fencing Chapter 560

560.03(2) Wire Fencing

The Standard Plans and the Standard Specifications contain details for the two approved types
of wire fence. The recommended uses for each type of fence are as follows:

560.03(2)(a) Type 1

This fence is used in urban and suburban areas where improvements along the right of way are
infrequent and future development is not anticipated. It may also be used adjacent to livestock
grazing areas. The lower portion of this fence is wire mesh and provides a barrier to children and
small animals.
560.03(2)(b) Type 2

This fence is used in farming areas to limit highway crossings by farm vehicles to designated
approaches. These areas include irrigation districts to prevent ditch riders, maintenance
personnel, and farmers from making unauthorized highway crossings, and where new alignment
crosses parcels previously enclosed by barbed wire.

560.03(3) Other Considerations

Extremely tall fences (7 to 10 feet high) may be used in areas where there are exceptional
conditions such as large concentrations of deer or elk. (See the region Environmental Services
Office and the Roadside Manual concerning wildlife management.)

Metal fencing can interfere with airport traffic control radar. When locating fencing in the
vicinity of an airport, contact the Federal Aviation Administration to determine whether metal
fence will create radar interference at the airport. If so, use nonmetallic fencing.

Do not straddle or obstruct surveying monuments with any type of fencing.

560.04 Gates
Keep the number of fence gates along limited access highways to a minimum. On limited access
highways, all new gates must be approved as described in Chapter 550.

Usually such gates are necessary only to allow highway maintenance personnel and operating
equipment to reach the state right of way without using the highway or freeway main line.
Gates may be needed to provide access to utility supports, manholes, and so on, located within
the right of way.

Use gates of the same type as each fence, and provide locks to deter unauthorized use.

In highly developed and landscaped areas where maintenance equipment is parked outside the
fence, provide the double gate shown in the Standard Plans.

Where continuous fencing is not provided on limited access highways (see Chapter 530),
approaches are normally gated and locked, with a short section of fence on both sides of the
gate.

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Chapter 560 Fencing

560.05 Procedure
Fencing is addressed in the access report (see Chapter 530) and the Plans, Specifications, and
Estimates, in accordance with the Plans Preparation Manual.

560.06 Documentation
Refer to Chapter 300 for design documentation requirements.

560.07 References

560.07(1) Design Guidance

Plans Preparation Manual, M 22-31, WSDOT

Roadside Manual, M 25-30, WSDOT

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications),
M 41-10, WSDOT

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Fencing Chapter 560

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 Investigation of Soils,
Chapter 610 Rock, and Surfacing Materials
610.01 General
610.02 References
610.03 Materials Sources
610.04 Geotechnical Investigation, Design, and Reporting
610.05 Use of Geotechnical Consultants
610.06 Geotechnical Work by Others
610.07 Surfacing Report
610.08 Documentation

610.01 General
It is the Washington State Department of Transportation’s (WSDOT’s) responsibility to
understand the characteristics of the soil and rock materials that support or are adjacent to
a transportation facility so that, when designed, constructed, and maintained, the facility will
be adequate to safely carry the estimated traffic. It is also the responsibility of WSDOT to
ensure the quality and quantity of all borrow, soils, rock, and surfacing materials used in the
construction of transportation facilities. Specific requirements for geotechnical investigation,
design, construction, and maintenance support are set forth in the WSDOT Geotechnical Design
Manual.
The following information serves as guidance in the above areas. When a project consists of
a surface overlay on an existing highway, the WSDOT Pavement Policy is used.
Before making project budget and schedule commitments to the Legislature, other agencies,
and the public, it is necessary to identify the extent and estimated cost for a project. Contact
the Region Materials Engineer (RME) and the Headquarters (HQ) Geotechnical Office as early
as possible to obtain conceptual-level recommendations regarding how the project soil, rock,
and groundwater conditions may affect the design of the project elements. The project soil, rock,
and groundwater conditions, and the availability, quantity, and quality of borrow and surfacing
materials, can affect the project scope, schedule, and budget.
The RME and the HQ Geotechnical Office will use existing subsurface information and their
Coordinate early
in your project knowledge of the project area to assess the subsurface conditions within the project limits. If there
for geotechnical is little information available or the information is poor, and the subsurface conditions have the
reporting and potential to significantly affect the project budget or schedule, it may be necessary to obtain
design. a limited number of geotechnical borings or test pits during Project Definition to assess soil,
rock, and groundwater conditions within the project limits. Once the Project Definition
has been developed and project funding secured, a more detailed geotechnical investigation
follows during the design and Plans, Specifications, and Estimates (PS&E) phases.
It is essential to involve the RME and the HQ Geotechnical Office in the design as soon as
possible once the need for geotechnical work is identified. (See 610.04(3) for time-estimate
information.) If major changes occur as the project is developed, inform the RME and the HQ
Geotechnical Office as soon as possible so that the geotechnical design can be adapted to the
changes without significant delay to the project.

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Investigation of Soils, Rock, and Surfacing Materials Chapter 610

610.02 References
610.02(1) Design Guidance
Construction Manual, M 41-01, WSDOT
Geotechnical Design Manual, M 46-03, WSDOT
Hydraulics Manual, M 23-03, WSDOT
Plans Preparation Manual, M 22-31, WSDOT
Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01,
WSDOT
Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications),
M 41-10, WSDOT
WSDOT Pavement Policy – See Pavements website:
 www.wsdot.wa.gov/business/materialslab/pavements/default.htm

610.03 Materials Sources

610.03(1) General
The region Project Development Engineer determines when a materials source is needed. The
RME determines the best materials source for the project (see Exhibit 610-1). It is preferred that
existing approved materials source sites be used when there are suitable sites available. When
there are no approved sites available, the RME determines the locations for new materials
sources. The RME contacts the HQ Geotechnical Office to provide a geotechnical investigation
for the proposed site. The HQ Geotechnical Office provides geologic mapping of the site;
develops a subsurface exploration plan and cost estimate; conducts the subsurface investigation;
develops a subsurface geologic model including groundwater; evaluates slope stability issues;
and makes recommendations. The HQ Geotechnical Office develops and provides a geotechnical
report with materials source development recommendations to the RME. The RME uses this
report and materials source recommendations to develop the Materials Source Report and to
identify the quantity and quality of material that are intended for the life of the materials source.
Specific requirements for materials source investigations are set forth in the Geotechnical Design
Manual.

610.03(2) Materials Source Approval

The HQ Geotechnical Office must review and approve the Materials Source Report produced by
the RME to ensure consistency with the geotechnical report produced by the HQ Geotechnical
Office.
The HQ Materials Office and the HQ Design Office must approve each pit or quarry site before
it is purchased, leased, or acquired on a royalty basis. Until the approval process is complete, the
project cannot be advertised for bids. Local and state permits are required for materials sources.
To avoid delay in advertising the project, begin the site investigations and permitting process in
the early stages of the Project Definition phase.

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Chapter 610 Investigation of Soils, Rock, and Surfacing Materials

610.04 Geotechnical Investigation, Design, and Reporting

610.04(1) General
A geotechnical investigation is conducted on all projects that involve significant grading
quantities (including state-owned materials source development), unstable ground, foundations
for structures, and groundwater impacts (including infiltration). The goal of the geotechnical
investigation is to preserve the safety of those who use the facility, as well as to preserve the
economic investment by the state of Washington. Additional requirements regarding geotechnical
investigations and who conducts these investigations are set forth in the Geotechnical Design
Manual.

610.04(2) Key Contacts for Initiating Geotechnical Work

For regions, the RME is the first person to contact for geotechnical work. Projects with
structures designed by the HQ Bridge and Structures Office, Washington State Ferries
(WSF) projects, and Urban Corridors projects generally require the involvement of the HQ
Geotechnical Office. These particular WSDOT offices should contact the HQ Geotechnical
Office directly for their geotechnical project needs. The specific roles and responsibilities of
the RME and HQ Geotechnical Office, including application to the Project Management
Process (PMP), are set forth in the Geotechnical Design Manual.
For information on retaining walls and noise walls, see Design Manual Chapters 730 and 740,
respectively. For geosynthetic design, see Chapter 630.

610.04(3) Scheduling Considerations for Geotechnical Work

The region Project Office, the HQ Bridge and Structures Office, the WSF, and the HQ Facilities
Office are responsible for identifying the potential need for geotechnical work and requesting
time and budget estimates from the RME or the HQ Geotechnical Office as early as possible
to prevent delays to the project.
Once the geotechnical design request and the site data are received by the RME or the HQ
Geotechnical Office, it can take from two to six months or more to complete the geotechnical
design. Design completion depends on the complexity of the project, whether or not test holes
are needed, current workload, the need to give the work to consultants, and how long it takes
to obtain environmental permits and rights of entry.
If a consultant must be used, the minimum time required to complete a design (for even a simple
project) is typically two and a half months.
In true emergency situations (such as a highway blocked by a landslide or a collapsed bridge), it
is possible to get geotechnical design work completed (in-house or by consultants) more rapidly
to at least provide a design for temporary mitigation.
Consider all of these factors when deciding how soon (in general, as early as possible) to initiate
the geotechnical work for a project.
To incorporate geotechnical scheduling considerations into the overall project schedule, see
the Geotechnical Design Manual, which provides a description and discussion of the Master
Deliverables List (MDL) as it applies to geotechnical work.

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Investigation of Soils, Rock, and Surfacing Materials Chapter 610

610.04(4) Site Data and Permits Needed to Initiate Geotechnical Work

610.04(4)(a) Geotechnical Work During Project Definition Phase
To initiate geotechnical work on a project during the Project Definition phase, provide the
following information:
1. Project description.
2. Plan view or description showing the proposed alignment or alignment alternative(s).
3. Description of project scope as it relates to geotechnical features such as major cuts and
fills, walls, structures, and potential stormwater facilities.
610.04(4)(b) Geotechnical Work During Design and PS&E Phases
To initiate geotechnical work on a project during the design and PS&E phases, provide the
following information:
1. Project description.
2. Plan sheets showing:
• Station and location of cuts, fills, walls, bridges, retention/detention ponds, and other
geotechnical features to be designed.
• Existing utilities; as-built plans are acceptable.
• Right of way limits.
• Wetlands.
• Drainage features.
• Existing structures.
• Other features or constraints that could affect the geotechnical design or investigation.
3. Electronic files, or cross sections every 50 feet or as appropriate, to define existing and new
ground line above and below walls, cuts, fills, and other pertinent information.
• Show stationing.
• Show locations of existing utilities, right of way lines, wetlands, and other constraints.
• Show locations of existing structures that might contribute load to the cut, fill, wall, or
other structure.
4. Right of entry agreements and permits required for geotechnical investigation.
5. Due date and work order number.
6. Contact person.
When the alignment and any constraints (as noted above) are staked, the stationing on the plans
and in the field must be in the same units. Physical surveys are preferred to photogrammetric
surveys to ensure adequate accuracy of the site data.
Permits and agreements to be supplied by the region might include the following:
• HPA
• Shoreline permits
• Tribal lands and waters
• Railroad easement and right of way
• City, county, or local agency use permits
• Sensitive area ordinance permits

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Chapter 610 Investigation of Soils, Rock, and Surfacing Materials

The region Project Office is also responsible for providing survey locations of test holes once
the test holes have been drilled. The survey information includes the station, offset, elevation,
and test hole coordinates. Coordinates are the latitude and longitude or state plane coordinates
(north or south as appropriate), but not project coordinates.

610.04(5) Overview of Geotechnical Design Objectives for the Various Project

Stages
Geotechnical design objectives for the various design phases are described in the Geotechnical
Design Manual.

610.04(6) Earthwork
610.04(6)(a) Project Definition
The designer contacts and meets with the RME (and the HQ Geotechnical Office as needed) at
the project site to conduct a field review to help identify the geotechnical issues for the project.
In general, if soil/rock conditions are poor and/or large cuts or fills are anticipated, the RME
requests that the HQ Geotechnical Office participate in the field review and reporting efforts.
The designer provides a description and location of the proposed earthwork to the RME as
follows:
• For widening of existing facilities, the anticipated width, length, and location of the
widening, relative to the current facility, are provided.
• For realignments, the approximate new location proposed for the facility is provided.
• Locations in terms of length can be by milepost or stations.
A brief conceptual-level report that summarizes the results of the investigation is provided
to the designer.
610.04(6)(b) Project Design
Geotechnical data necessary to allow completion of the PS&E-level design is compiled during
the design phase. This includes soil borings, testing, and geotechnical design based on final
geometric data. Detailed design of cut and fill slopes can be done once the roadway geometry
is established and geotechnical data are available. The purpose of this design effort is to
determine the maximum stable cut or fill slope and, for fills, the potential for short- and long-
term settlement. Also, the usability of the cut materials and the type of borrow needed for the
project (if any) are evaluated. Evaluate the use of soil bioengineering as an option for building
steeper slopes or to prevent surface erosion. (See Roadside Manual Chapter 740, Soil
Bioengineering, for more information.)
The designer requests a geotechnical report from the RME. The site data given in 610.04(4),
as applicable, is provided. It is important that the request for the geotechnical report be made
as early as possible in the design phase. Cost and schedule requirements to generate the report
are project-specific and can vary widely. The time required to obtain permits and rights of entry
must be considered when establishing schedule requirements.
The Geotechnical Design Manual, Chapter 24, summarizes the type of information and
recommendations that are typically included in the geotechnical report for earthwork. The
recommendations should include the background regarding analysis approach and any
agreements with the region or other customers regarding the definition of acceptable
level of risk.

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Investigation of Soils, Rock, and Surfacing Materials Chapter 610

The region Project Office uses the report to finalize design decisions for the project. To meet
slope stability requirements, additional right of way might be required or a wall might be needed.
Wall design is covered in Chapter 730. Construction timing might require importing material
rather than using cut materials. The report is used to address this and other constructibility issues.
The report is also used to proceed with completion of the PS&E.
610.04(6)(c) PS&E Development
Adequate geotechnical design information to complete the PS&E is typically received during
the design phase. Additional geotechnical work might be needed when right of way cannot be
acquired, restrictions are included in permits, or other requirements are added that result in
changes to the design.
Special provisions and plan details, if not received as part of the report provided during design,
are developed with the assistance of the RME or the HQ Geotechnical Office. The designer uses
this information, as well as the design phase report, to complete the PS&E documents. Both the
region Materials Laboratory and the HQ Geotechnical Office can review (if requested) the
contract plans before the PS&E review process begins. Otherwise, they will review the
contract plans during the normal PS&E review process.

610.04(7) Hydraulic Structures, Ponds, and Environmental Mitigation

610.04(7)(a) Project Definition
The designer provides a description and location of the proposed hydraulic/ environmental
improvements and other pertinent site information and discusses the extent of the improvements
with both the RME and the HQ Hydraulics Section to identify the geotechnical issues to be
investigated. At this stage, only the identification and feasibility of the proposed hydraulic
structures or environmental mitigation are investigated. The cost and schedule requirements
for the geotechnical investigation are also determined at this time.
Examples of hydraulic structures include, but are not limited to, large culverts, pipe arches,
underground detention vaults, and fish passage structures. Examples of environmental mitigation
include, but are not limited to, detention/retention ponds, wetland creation, and environmental
mitigation measures on fill slopes.
It is especially important to identify the potential to encounter high groundwater at the proposed
hydraulic structure or pond location. In general, avoid high groundwater locations (see the
Highway Runoff Manual) as groundwater can greatly affect design, constructibility, operations,
performance, and maintenance.
610.04(7)(b) Project Design
The designer requests a geotechnical report from the RME. The site data given in 610.04(4),
as applicable, is provided along with the following information:
• Pertinent field observations (such as unstable slopes, existing soft soils or boulders, evidence
of high groundwater, or erosion around and damage to existing culverts or other drainage
structures).
• Jurisdictional requirements for geotechnical design of berms/dams.
It is important that the request for the geotechnical report be made as early as possible in the
design phase. Cost and schedule requirements to generate the report are project-specific and
can vary widely. The time required to obtain permits and rights of entry must be considered
when establishing schedule requirements. Furthermore, since the depth to groundwater can be
critical to the feasibility of these types of facilities, and since seasonal variation of groundwater

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is typically important to know, it is essential to have adequate time to determine the effect of
seasonal variations on groundwater.
The RME, with support from the HQ Geotechnical Office as needed, provides the following
information in addition to the overall requirements specified in the Geotechnical Design Manual,
when requested and where applicable, as part of the project geotechnical report:
• Soil boring logs.
• Soil pH and resistivity.
• Water table elevation.
• Soil infiltration rates (the highest rate for assessing spill containment/aquifer protection
and the long-term rate for determining pond capacity).
• Bearing capacity and settlement for hydraulic structure foundations.
• Slope stability for ponds.
• Retention berm/dam design.
• Potential for and amount of differential settlement along culverts and pipe arches and the
estimated time required for settlement to occur.
• Soil pressures and properties (primarily for underground detention vaults).
• Erosion potential.
• Geosynthetic design in accordance with Chapter 630.
• Recommendations for mitigation of the effects of soft or unstable soil on the hydraulic
structures.
• Recommendations for construction.
Note that retaining walls that are part of a pond, fish passage, and so on, are designed in
accordance with Chapter 730 and the Geotechnical Design Manual.
The designer uses the geotechnical information to:
• Finalize design decisions.
• Evaluate and mitigate environmental issues.
• Proceed with completion of the PS&E design. This includes determining the most cost-
effective hydraulic structure/pond to meet the desired objectives; locating and sizing ponds
and foundations for hydraulic structures; structural design; mitigating the effects of
settlement; and satisfying local jurisdictional requirements for design.
610.04(7)(c) PS&E Development
During PS&E development, the designer uses the information provided in the geotechnical report
to:
• Select pipe materials in accordance with corrosion, resistivity, and abrasion guidelines in the
Hydraulics Manual.
• Consider and include construction recommendations.
Additional design and specification guidance and support from the RME or the HQ Geotechnical
Office are sought as needed. Both sections provide careful review of the contract plans before the
PS&E review process begins, if requested. Otherwise, they will review the contract plans during
the normal PS&E review process.

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610.04(8) Signals, Sign Bridges, Cantilever Signs, and Luminaire Foundations

610.04(8)(a) Project Definition and Design
Geotechnical information is usually not required for signals, sign bridges, cantilever signs, and
luminaires during Project Definition.
The region Traffic Design Office contacts the RME for conceptual foundation recommendations.
The conceptual recommendations are based on existing information in the area and identify
whether Standard Plan foundations are feasible or whether special-design foundations are
required. If good soils are anticipated or the foundations will be placed in fill, Standard Plan
foundations can be assumed. If special-design foundations are required, additional time and
money can be included in the project to accommodate increased field exploration for foundation
design, HQ Geotechnical Office involvement, and structural design by the HQ Bridge and
Structures Office.
610.04(8)(b) PS&E Development
Foundation recommendations are made by either the RME or the HQ Geotechnical Office. The
recommendations provide all necessary geotechnical information to complete the PS&E.
The region Traffic Design Office (or region Project Engineer in some cases) is responsible for
delivering the following project information to the RME:
• Plan sheet showing the location of the structures (station and offset) and the planned structure
type.
• Applicable values for: XYZ coordinates, strain pole class, sign bridge span length, luminaire
height, variable message sign weight, wind load, CCTV pole height, and known utility
information in the area.
The RME provides the following information to the requester if Standard Plans foundation types
can be used:
• Allowable lateral bearing capacity of the soil
• Results of all field explorations
• Groundwater elevation
• Foundation constructibility
The region uses this information to complete the plan sheets and prepare any special provisions.
If utilities are identified during the field investigation that could conflict with the foundations,
the region pursues moving or accommodating the utility. Accommodation could require special
foundation designs.
If special designs are required, the RME notifies the requester that special designs are required
and forwards the information received from the region to the HQ Geotechnical Office. The
HQ Geotechnical Office provides the HQ Bridge and Structures Office with the necessary
geotechnical recommendations to complete the foundation designs. The region coordinates
with the HQ Bridge and Structures Office to ensure they have all the information necessary
to complete the design. Depending on the structure type and complexity, the HQ Bridge and
Structures Office might produce the plan sheets and special provisions for the foundations, or
they might provide the region with information so they can complete the plan sheets and special
provisions.
Additional guidelines and requirements for design of foundations for these types of structures are
contained in the Geotechnical Design Manual.

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610.04(9) Buildings, Park & Ride Lots, Communication Towers, and Rest Areas
In general, the RME functions as the clearinghouse for the geotechnical work to be conducted
in each of the phases, for technical review of the work if it is performed by consultants, or for
getting the work done in-house. For sites and designs that are more geotechnically complex, the
RME contacts the HQ Geotechnical Office for assistance. (See the Geotechnical Design Manual
for geotechnical investigation and design requirements for these types of facilities.)

610.04(9)(a) Site Selection

Conceptual geotechnical investigation (based on historical data and minimal subsurface
investigation) of several alternative sites is performed in which the geotechnical feasibility
of each site for its intended use is evaluated, allowing the sites to be ranked. In this phase,
geological hazards (such as landslides, rockfall, compressible soils, and liquefaction) are
identified, and geotechnical data adequate to determine a preliminary cost to develop and
build on the site is gathered.
610.04(9)(b) Schematic Design
For the selected site, the best locations for structures, utilities, and other elements of the project
are determined based on site constraints and ground conditions. In this phase, the site is
characterized more thoroughly than in the site selection phase, but subsurface exploration
is not structure specific.
610.04(9)(c) Design and PS&E Development
The final locations of each of the project structures, utilities, and other project elements
determined from the schematic design phase are identified. Once these final locations are
available, a geotechnical investigation is conducted that is adequate to complete the final design
of each of the project elements, such as structure foundations, detention/retention facilities,
utilities, parking lots, roadways, and site grading. From this investigation and design, the
final PS&E is developed.

610.04(10) Retaining Walls, Reinforced Slopes, and Noise Walls

610.04(10)(a) Project Definition
The designer provides the RME with a description and location of the proposed walls or
reinforced slopes, including the potential size of the proposed structures and other pertinent
site information. At this stage, only the identification and feasibility of the proposed walls
or reinforced slopes are investigated. A field review may also be conducted as part of the
investigation effort. In general, if soil/rock conditions are poor and/or large walls or reinforced
slopes are anticipated, the RME requests that the HQ Geotechnical Office participate in the
field review and reporting efforts. The cost and schedule requirements for the geotechnical
investigation are also determined at this time.
A brief conceptual-level report that summarizes the results of the investigation may be provided
to the designer at this time, depending on the complexity of the geotechnical issues.

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610.04(10)(b) Project Design and PS&E Development

Geotechnical data necessary to allow completion of the PS&E-level design for walls and
reinforced slopes are compiled during the design and PS&E development phases. These include
soils borings, testing, and final geometric data. Detailed designs of walls and reinforced slopes
can be done once the roadway geometry is established and geotechnical data are available. The
purpose of this design effort is to determine the wall and slope geometry needed for stability;
noise wall and retaining wall foundation requirements; and the potential for short- and long-
term settlement.
The designer requests a geotechnical report from the RME for retaining walls, noise walls, and
reinforced slopes that are not part of the bridge preliminary plan. For walls that are part of the
bridge preliminary plan, the HQ Bridge and Structures Office requests the geotechnical report for
the walls from the HQ Geotechnical Office. (See Chapter 730 for the detailed design process for
retaining walls and reinforced slopes, Chapter 740 for the detailed design process for noise walls,
and the Geotechnical Design Manual for design requirements for all walls.) It is important that
requests for a geotechnical report be made as early as possible in the design phase. The time
required to obtain permits and rights of entry must be considered when establishing schedule
requirements.
For retaining walls and reinforced slopes, the site data to be provided with the request for a
geotechnical report are as given in Chapter 730. Supply right of entry agreements and permits
required for the geotechnical investigation. The site data given in 610.04(4), as applicable, are
provided for noise walls.
The RME or the HQ Geotechnical Office provides the information (see Chapter 730 or 740 for
specific responsibilities for design) specified in the Geotechnical Design Manual as part of the
project geotechnical report.
The recommendations may also include the background regarding the analysis approach and any
agreements with the region or other customers regarding the definition of acceptable level of risk.
Additional details and design issues to be considered in the geotechnical report are as provided
in Chapter 730 for retaining walls and reinforced slopes and in Chapter 740 for noise walls. The
designer uses this information for final wall/reinforced slope selection and to complete the PS&E.
For final PS&E preparation, special provisions and plan details (if not received as part of
the report provided during design) are developed with the assistance of the region Materials
Laboratory or the HQ Geotechnical Office. Both the region Materials Laboratory and the HQ
Geotechnical Office can review the contract plans before the PS&E review process begins,
if requested. Otherwise, they will review the contract plans during the normal PS&E
review process.

610.04(11) Unstable Slopes

Unstable slope mitigation includes the stabilization of known landslides and rockfall that occur
on slopes adjacent to the WSDOT transportation system and that have been programmed under
the P3 Unstable Slope Program.
610.04(11)(a) Project Definition
The region Project Office provides the RME with a description and location of the proposed
unstable slope mitigation work. Location of the proposed work can be milepost limits or
stationing. The designer meets at the project site with the RME and HQ Geotechnical Office to
conduct a field review, discuss project requirements, and identify geotechnical issues associated
with the unstable slope project. The RME requests that the HQ Geotechnical Office participate
in the field review and Project Definition reporting.

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The level of work in the Project Definition phase for unstable slopes is conceptual in nature, not
a final design. The geotechnical investigation generally consists of a field review, a more detailed
assessment of the unstable slope, review of the conceptual mitigation developed during the
programming phase of the project, and proposed modification (if any) to the original conceptual-
level unstable slope mitigation. The design phase geotechnical services cost and schedule,
including any required permits, are determined at this time. A brief conceptual-level report is
provided to the designer that summarizes the results of the Project Definition investigation.
610.04(11)(b) Project Design
Geotechnical information and field data necessary to complete the unstable slope mitigation
design is compiled during this design phase. This work includes, depending on the nature of the
unstable slope problem, test borings, rock structure mapping, geotechnical field instrumentation,
laboratory testing, and slope stability analysis. The purpose of this design effort is to provide
design-level geotechnical recommendations to stabilize the known unstable slope.
The designer requests a geotechnical report from the HQ Geotechnical Office through the RME.
The site data given in 610.04(4), as applicable, is provided along with the following information:
• A plan sheet showing the station and location of the proposed unstable slope mitigation
project.
• If requested, the Digital Terrain Model (DTM) files necessary to define the on-ground
topography of the project site (the limits of the DTM will have been defined during the
Project Definition phase).
It is important that the request for the geotechnical report be made as early as possible in the
design phase. Cost and schedule requirements to generate the report are project-specific and
can vary widely. Unstable slope design investigations might require geotechnical monitoring
of ground movement and groundwater over an extended period of time to develop the required
field information for the unstable slope mitigation design. The time required to obtain rights of
entry and other permits, as well as the long-term monitoring data, must be considered when
establishing schedule requirements for the geotechnical report.
In addition to the geotechnical report requirements specified in the Geotechnical Design Manual,
the HQ Geotechnical Office provides the following information as part of the project
geotechnical report (as applicable):
• Unstable slope design analysis and mitigation recommendations.
• Constructibility issues associated with the unstable slope mitigation.
• Appropriate special provisions for inclusion in the contact plans.
The region Project Office uses the geotechnical report to finalize the design decisions for the
project and the completion of the PS&E design.
610.04(11)(c) PS&E Development
Adequate geotechnical design information to complete the PS&E is typically obtained during the
project design phase. Additional geotechnical work might be needed when right of way cannot
be acquired, restrictions are included in permits, or other requirements are added that result in
changes to the design.

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Special provisions, special project elements, and design details, if not received as part of the
design phase geotechnical report, are developed with the assistance of the RME and the HQ
Geotechnical Office. The designer uses this information in conjunction with the design phase
geotechnical report to complete the PS&E document. The RME and the HQ Geotechnical Office
can review the contract plans before the PS&E review begins, if requested. Otherwise, they will
review the contract plans during the normal PS&E review process.

610.04(12) Rockslope Design

610.04(12)(a) Project Definition
The region Project Office provides the RME with a description and location of the proposed
rock excavation work. For widening of existing rock cuts, the anticipated width and length of the
proposed cut in relationship to the existing cut are provided. For new alignments, the approximate
location and depth of the cut are provided. Location of the proposed cut(s) can be milepost limits
or stationing. The designer meets at the project site with the RME and the HQ Geotechnical
Office to conduct a field review, discuss project requirements, and identify any geotechnical
issues associated with the proposed rock cuts. The RME requests that the HQ Geotechnical
Office participate in the field review and Project Definition reporting.
The level of rockslope design work for the Project Definition phase is conceptual in nature.
The geotechnical investigation generally consists of the field review, review of existing records,
an assessment of existing rockslope stability, and preliminary geologic structure mapping. The
focus of this investigation is to assess the feasibility of the rock cuts for the proposed widening
or realignment, not final design. A brief conceptual-level report that summarizes the result of the
Project Definition investigation is provided to the designer.
610.04(12)(b) Project Design
Detailed rockslope design is done once the roadway geometrics have been established.
The rockslope design cannot be finalized until the roadway geometrics have been finalized.
Geotechnical information and field data necessary to complete the rockslope design are
compiled during this design phase. This work includes rock structure mapping, test borings,
laboratory testing, and slope stability analysis. The purpose of this design effort is to determine
the maximum stable cut slope angle and any additional rockslope stabilization measures that
could be required.
The designer requests a geotechnical report from the HQ Geotechnical Office through the RME.
The site data given in 610.04(4), as applicable, is provided.
It is important that the request for the geotechnical report be made as early as possible in the
design phase. Cost and schedule requirements to generate the report are project-specific and can
vary widely. The time required to obtain permits and rights of entry must be considered when
establishing schedule requirements.
In addition to the geotechnical report requirements specified in the Geotechnical Design Manual,
the HQ Geotechnical Office provides the following information as part of the project
geotechnical report pertaining to rockslope design analysis and recommendations:
• Type of rockslope design analysis conducted and limitation of the analysis. Also included
will be any agreements with the region and other customers regarding the definition of
“acceptable risk.”
• The slope(s) required for stability.
• Additional slope stabilization requirements (such as rock bolts or rock dowels).
• Rockslope ditch criteria (see Chapter 1239).
• Assessment of rippability.
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• Blasting requirements, including limitations on peak ground vibrations and air blast over-
pressure if required.
• Usability of the excavated material, including estimates of shrink and swell.
• Constructibility issues associated with the rock excavation.
The region Project Office uses the geotechnical report to finalize the design decisions for the
project and the completion of the PS&E design for the rockslope elements of the project.
610.04(12)(c) PS&E Development
Adequate geotechnical design information to complete the PS&E is typically obtained during
the design phase. Additional geotechnical work might be needed when right of way cannot
be acquired, restrictions are included in permits, or other requirements are added that result
in change to the design.
Special provisions, special blasting requirements, and plan details, if not received as part of
the design phase geotechnical report, are developed with the assistance of the RME or the HQ
Geotechnical Office. The designer uses this information in conjunction with the design phase
geotechnical report to complete the PS&E documents. The RME and the HQ Geotechnical Office
can review (if requested) the contract plans before the PS&E review begins. Otherwise, they will
review the contract plans during the normal PS&E review process.

610.04(13) Bridge Foundations

610.04(13)(a) Project Definition
The HQ Geotechnical Office supports the development of reasonably accurate estimates of bridge
substructure costs beginning with the Project Definition phase. A field review is recommended
for major projects and projects that are located in areas with little or no existing geotechnical
information. The region office responsible for Project Definition coordinates field reviews.
Subsurface exploration (drilling) is usually not required at this time, but might be needed if cost
estimates cannot be prepared within an acceptable range of certainty.
Once it has received the necessary site data from the region Project Office, the HQ Bridge and
Structures Office is responsible for delivering the following project information to the HQ
Geotechnical Office:
• Alternative alignments and/or locations of bridge structures.
• A preliminary estimate of channelization (structure width).
• Known environmental constraints.
The HQ Geotechnical Office provides the following to the HQ Bridge and Structures and region
offices:
• Summary of existing geotechnical information.
• Identification of geotechnical hazards (such as slides, liquefiable soils, and soft-soil deposits).
• Identification of permits that might be required for subsurface exploration (drilling).
• Conceptual foundation types and depths.
• If requested, an estimated cost and time to complete a geotechnical foundation report.
The HQ Bridge and Structures Office uses this information to refine preliminary bridge costs.
The region Project Office uses the estimated cost and time to complete a geotechnical foundation
report to develop the project delivery cost and schedule.

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610.04(13)(b) Project Design

The HQ Geotechnical Office assists the HQ Bridge and Structures Office with preparation of the
bridge preliminary plan. Geotechnical information gathered for Project Definition will normally
be adequate for this phase, as test holes for the final bridge design cannot be drilled until accurate
pier location information is available. For selected major projects, a type, size, and location
(TS&L) report might be prepared, which usually requires some subsurface exploration to provide
a more detailed, though not final, estimate of foundation requirements.
The HQ Bridge and Structures Office is responsible for delivering the following project
information, based on bridge site data received from the region Project Office, to the HQ
Geotechnical Office:
• Anticipated pier locations.
• Approach fill heights.
• For TS&L, alternate locations/alignments/structure types.
The HQ Bridge and Structures Office can expect to receive the following:
• Conceptual foundation types, depths, and capacities.
• Permissible slopes for bridge approaches.
• For TS&L, a summary of site geology and subsurface conditions, and more detailed
preliminary foundation design parameters and needs.
• If applicable or requested, the potential impact of erosion or scour potential (determined
by the HQ Hydraulics Section) on foundation requirements.
The HQ Bridge and Structures Office uses this information to complete the bridge preliminary
plan. The region Project Office confirms right of way needs for approach embankments. For
TS&L, the geotechnical information provided is used for cost estimating and preferred alternate
selection. The preliminary plans are used by the HQ Geotechnical Office to develop the site
subsurface exploration plan.
610.04(13)(c) PS&E Development
During this phase, or as soon as a 95% preliminary plan is available, subsurface exploration
(drilling) is performed and a geotechnical foundation report is prepared to provide all necessary
geotechnical recommendations needed to complete the bridge PS&E.
The HQ Bridge and Structures Office is responsible for delivering the following project
information to the HQ Geotechnical Office:
• 95% preliminary plans, concurrent with distribution for region approval.
• Estimated foundation loads and allowable settlement criteria for the structure when requested.
The HQ Bridge and Structures Office can expect to receive:
• The bridge geotechnical foundation report.
The HQ Bridge and Structures Office uses this information to complete the bridge PS&E. The
region Project Office reviews the geotechnical foundation report for construction considerations
and recommendations that might affect region items, estimates, staging, construction schedule,
or other items.
Upon receipt of the structure PS&E review set, the HQ Geotechnical Office provides the HQ
Bridge and Structures Office with a Summary of Geotechnical Conditions for inclusion in
Appendix B of the contract.

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610.04(14) Geosynthetics
For design guidance on geosynthetics, refer to Chapter 630.

610.04(15) Washington State Ferries Projects

610.04(15)(a) Project Design
The HQ Geotechnical Office assists the Washington State Ferries (WSF) with determining the
geotechnical feasibility of all offshore facilities, terminal facility foundations, and bulkhead walls.
For upland retaining walls and grading, utility trenches, and pavement design, the RME assists
WSF with determining geotechnical feasibility.
In addition to the site data provided in Section 610.04(4), as applicable, the following information
is supplied by WSF to the HQ Geotechnical Office or the RME, as appropriate, with the request
for the project geotechnical report:
• A plan showing anticipated structure locations as well as existing structures.
• Relevant historical data for the site.
• A plan showing utility trench locations.
• Anticipated utility trench depths.
• Proposed roadway profiles.
WSF can expect to receive the following:
• Results of any borings or laboratory tests conducted.
• A description of geotechnical site conditions.
• Conceptual foundation types, depths, and capacities.
• Conceptual wall types.
• Assessment of constructibility issues that affect feasibility.
• Surfacing depths and/or pavement repair and drainage schemes.
• If applicable or requested, potential impact of erosion or scour potential (determined by the
HQ Hydraulics Section) on foundation requirements.
WSF uses this information to complete the design report, design decisions, and estimated budget
and schedule.
WSF is responsible for obtaining any necessary permits or right of entry agreements needed to
access structure locations for the purpose of subsurface exploration (such as test hole drilling).
The time required for obtaining permits and rights of entry must be considered when developing
project schedules. Possible permits and agreements might include, but are not limited to:
• City, county, or local agency use permits.
• Sensitive area ordinance permits.
610.04(15)(b) PS&E Development
Subsurface exploration (drilling) is performed and a geotechnical foundation report is prepared
to provide all necessary geotechnical recommendations needed to complete the PS&E.
The designer requests a geotechnical report from the HQ Geotechnical Office or the RME, as
appropriate. The site data given in 610.04(4), as applicable, is provided along with the following
information:
• A plan showing final structure locations as well as existing structures.
• Proposed structure loadings.

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WSF can expect to receive the following:

• Results of any borings or laboratory tests conducted.
• A description of geotechnical site conditions.
• Final foundation types, depths, and capacities.
• Final wall types and geotechnical designs/parameters for each wall.
• Assessment of constructibility issues to be considered in foundation selection and
when assembling the PS&E.
• Pile driving information: driving resistance and estimated overdrive.
• Surfacing depths and/or pavement repair and drainage schemes.
WSF uses this information to complete the PS&E.
Upon receipt of the WSF PS&E review set, the HQ Geotechnical Office provides WSF with
a Summary of Geotechnical Conditions for inclusion in Appendix B of the Contract. A Final
Geotechnical Project Documentation package is assembled by the HQ Geotechnical Office and
sent to WSF or the Plans Branch, as appropriate, for reproduction and sale to prospective bidders.

610.05 Use of Geotechnical Consultants

Prior to authorizing a consultant to conduct the geotechnical investigation for a project, the region
Project Office, the HQ Geotechnical Office, and the RME determine the scope of work and
schedule for the project and whether or not the project will go to a geotechnical consultant.
Once the decision has been made to have a consultant conduct the geotechnical investigation for
a project, the HQ Geotechnical Office or the RME assists in developing the geotechnical scope
and estimate for the project (WSDOT Consultant Services assists in this process). A team
meeting between the consultant team, the region or Washington State Ferries (depending on
whose project it is), and the HQ Geotechnical Office/RME is conducted early in the project
to develop technical communication lines and relationships. Good proactive communication
between all members of the project team is crucial to the success of the project due to the
complex supplier-client relationships.
Additional guidelines on the use of geotechnical consultants and the development of a scope
of work for the consultant are provided in the Geotechnical Design Manual.

610.06 Geotechnical Work by Others

Geotechnical design work conducted for the design of structures, or other engineering works by
other agencies or private developers within the right of way, is subject to the same geotechnical
engineering requirements as for engineering works performed by WSDOT. Therefore, the
provisions contained within this chapter also apply in principle to such work. All geotechnical
work conducted for engineering works within the WSDOT right of way or that otherwise directly
impacts WSDOT facilities must be reviewed and approved by the HQ Geotechnical Office or the
RME, depending on the nature of the work.
Additional requirements for geotechnical work by others that impacts WSDOT facilities and land
within the WSDOT right of way are set forth in the Geotechnical Design Manual.

610.07 Surfacing Report

Detailed criteria and methods that govern pavement rehabilitation can be found in the WSDOT
Pavement Policy. The RME provides the surfacing report to the region Project Office. This report
provides recommended pavement types, surfacing depths, pavement drainage recommendations,
and pavement repair recommendations.

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610.08 Documentation
610.08(1) Design Documentation
Refer to Chapter 300 for design documentation requirements.

610.08(2) Final Geotechnical Project Documentation and Geotechnical

Information for the Construction Contract
Once a project PS&E is near completion, all of the geotechnical design memorandums and
reports are compiled together to form the Final Geotechnical Project Documentation, to be
published for the use of prospective bidders. The detailed process for this is located in the Plans
Preparation Manual.
Geotechnical information included in the contract consists of the final project boring logs and,
as appropriate for the project, a Summary of Geotechnical Conditions. The boring logs from the
geotechnical reports are incorporated into the contract by the region, WSF, or Urban Corridors
Office (UCO) staff. The Summary of Geotechnical Conditions is provided to the region, WSF,
or UCO by the HQ Geotechnical Office and/or RME.
Additional geotechnical project documentation requirements are set forth in the Geotechnical
Design Manual.

WSDOT Design Manual M 22-01.10 Page 610-17

July 2013
Investigation of Soils, Rock, and Surfacing Materials Chapter 610

Design Project
Identified

Region Determines
Source Required

RME Determines
Materials Source

RME Determines
Source Approved Source Not Approved
Source Status

RME Materials RME Evaluates

Reviews Existing Data

HQ Materials Lab Data Does Not

Data Supports Use No Data
Reviews Support Use

HQ Materials Lab RME Requests

Concurs Geotechnical
Investigation

Materials Source in Geotechnical

Contract Investigation
Performed by HQ
Geotechnical Office

RME Rejects
Geotechnical Report
Materials Site

RME Develops RME Source

Mining Plan Reclamation Plan

RME Prepares
Materials Source Approval by Others
Report

HQ Materials Lab
Reviews Report

Materials Source Materials Source

Materials Source
Rejected by HQ Available for Future
Approved
Materials Lab Contracts

Materials Source in
Contract

Materials Source Development

Exhibit 610-1

Page 610-18 WSDOT Design Manual M 22-01.10

July 2013
Chapter 620 Design of Pavement Structure
620.01 General
620.02 Estimating Tables

620.01 General
Detailed criteria and methods that govern pavement design are in the Washington State
Department of Transportation (WSDOT) Pavement Policy, which is available from the Pavements
website:  www.wsdot.wa.gov/business/materialslab/pavements/default.htm

The pavement design for all Design-Build project Request For Proposals (RFPs) will be conducted
by the State Materials Lab, Pavement Division.

620.02 Estimating Tables

The tables in Exhibits 620-1 through 620-5h are for developing estimates of quantities for
pavement sections, shoulder sections, stockpiles, asphalt distribution, and fog seal.

Exhibit 620-1 Estimating: Miscellaneous Tables

Unit Dry Weight – Gravel Base and Surfacing

Truck Measure Compacted on Roadway
Type of Material
lb/cy T/cy lb/cy T/cy
Ballast 3,100 1.55 3,900 1.95
Crushed Surfacing Top Course 2,850 1.43 3,700 1.85
Crushed Surfacing Base Course 2,950 1.48 3,700 1.85
Screened Gravel Surfacing 3,700 1.85
*Gravel Base 3,400 – 3,800 1.70 – 1.90
Permeable Ballast 2,800 1.40
*3,700 lb/cy (1.85 tons/cy) is recommended as the most suitable factor; however, if the
grading approaches the coarseness of ballast, the factor would approach 3,800 lb/cy (1.90
tons/cy), and if the grading contains more than 45% sand, the factor would decrease,
approaching 3,400 lb/cy (1.70 tons/cy) for material that is essentially all sand.

Notes:
 Weights shown are dry weights and corrections are required for water contents.
 The tabulated weights for the materials are reasonably close; however, apply corrections in
the following order:

For specific gravity: Wt. = tabular wt. x specific gravity on surface report
2.65
For water content: Wt. = tabular wt. x (1 + free water % in decimals)

 If material is to be stockpiled, increase required quantities by 10% to allow for waste.

 Consider the inclusion of crushed surfacing top course material for keystone when estimating
quantities for projects having ballast course.

WSDOT Design Manual M 22-01.12 Page 620-1

November 2015
Design of Pavement Structure Chapter 620

Exhibit 620-2 Estimating: Hot Mix Asphalt Pavement and Asphalt Distribution Tables

Fog Seal
Asphalt
Type of Tons/Mile Width (ft)
Application Tons* per
Application Emulsified
gal* per sy sy 10 11 12
Asphalt
Fog Seal CSS-1/CSS-1h 0.07 0.000292 1.7 1.9 2.1
*Quantities shown are retained (residual) asphalt.

Specific Data[1][2]
Hot Mix Asphalt Paving Quantities (tons/mile)*
Width Depth of Pavement (ft)
(ft) 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75
4 161 241 321 402 482 563 643 723 804 884 964 1045 1125 1206
6 241 362 482 603 723 844 964 1085 1206 1326 1447 1567 1688 1808
8 321 482 643 804 964 1125 1286 1447 1607 1768 1929 2090 2250 2411
10 402 603 804 1005 1206 1407 1607 1808 2009 2210 2411 2612 2813 3014
11 442 663 884 1105 1326 1547 1768 1989 2210 2431 2652 2873 3094 3315
12 482 723 964 1206 1447 1688 1929 2170 2411 2652 2893 3135 3376 3617
22 884 1326 1768 2210 2652 3094 3536 3978 4421 4863 5305 5747 6189 6631
24 964 1447 1929 2411 2893 3376 3858 4340 4822 5305 5787 6269 6751 7234
*Based on 137 lbs/sy (0.0685 tons/sy) of 0.10 ft compacted depth = 2.05 tons/cy

Notes:
[1] The specific gravity of the aggregate will affect the weight of aggregate in the completed mix.
[2] Quantities shown do not provide for widening, waste from stockpile, or thickened edges.

Page 620-2 WSDOT Design Manual M 22-01.12

November 2015
Chapter 620 Design of Pavement Structure

Exhibit 620-3 Estimating: Bituminous Surface Treatment

Bituminous Surface Treatment[1]

Average Mineral Aggregate Average Asphalt[2][4]
Basic[3]
Type of Application Application 10 ft 11 ft 12 ft Spread 10 ft 11 ft 12 ft Asphalt
Used
lb/sy cy/sy T/mi cy/mi T/mi cy/mi T/mi cy/mi gal/sy gal/mi T/mi gal/mi T/mi gal/mi T/mi
New Construction 3/4 inch – 1/2 inch

First Application 0.50 2933 11.8 3227 13.0 3520 14.1 CRS-2P
Crushed Screenings 3/4 inch – 1/2 inch 35 0.0146 103 86 113 94 123 103
Second Application 0.48 2787 11.2 3065 12.3 3344 13.4 CRS-2P
Crushed Screenings 1/2 inch – No. 4 32 0.0121 93 71 103 78 113 85
Choke Stone No. 4 – 0 5 0.0017 15 10 16 11 18 12
Totals 72 0.0284 211 167 232 183 254 200 0.98 5720 23.0 6292 25.3 6864 27.5

New Construction 1/2 inch – No. 4

First Application 0.50 2933 11.8 3227 13.0 3520 14.1 CRS-2P
Crushed Screenings 1/2 inch – No. 4 35 0.0132 102 77 113 85 123 93
Second Application 0.48 2787 11.2 3065 12.3 3344 13.4 CRS-2P
Crushed Screenings 1/2 inch – No. 4 32 0.0121 93 71 103 78 113 85
Choke Stone No. 4 – 0 5 0.0017 15 10 16 11 18 12
Totals 72 0.0270 210 158 232 174 254 190 0.98 5720 23.0 6292 25.3 6864 27.5
Seal Coats 5/8 inch – No. 4

Seal Coat 0.53 3109 12.5 3420 13.7 3731 15.0 CRS-2P
Crushed Screenings 5/8 inch – No. 4 35 0.0130 102 76 113 84 124 92

Choke Stone No. 4 – 0 5 0.0017 15 10 16 11 18 12

Totals 40 0.0147 117 86 129 95 142 104 0.53 3109 12.5 3420 13.7 3731 15.0

Table and notes continued on the next page.

WSDOT Design Manual M 22-01.12 Page 620-3

November 2015
Design of Pavement Structure Chapter 620

Exhibit 620-3 Estimating: Bituminous Surface Treatment (continued)

Bituminous Surface Treatment[1]

Average Mineral Aggregate Average Asphalt[2][4]
Basic[3]
Type of Application Application 10 ft 11 ft 12 ft Spread 10 ft 11 ft 12 ft Asphalt
Used
lb/sy cy/sy T/mi cy/mi T/mi cy/mi T/mi cy/mi gal/sy gal/mi T/mi gal/mi T/mi gal/mi T/mi
Seal Coats 1/2 inch – No. 4
Seal Coat 0.45 2640 10.6 2904 11.7 3168 12.7 CRS-2P
Crushed Screenings 1/2 inch – No. 4 28 0.0106 81 62 89 68 97 74
Choke Stone No. 4 – 0 5 0.0017 15 10 16 11 18 12
Totals 33 0.0123 96 72 105 79 115 86 0.45 2640 10.6 2904 11.7 3168 12.7
Seal Coats 3/8 inch – No. 4
Seal Coat 0.45 2640 10.6 2904 11.7 3168 12.7 CRS-2P
Crushed Screenings 3/8 inch - No. 4 30 0.0106 88 62 96 68 106 75
Choke Stone No. 4 – 0 5 0.0017 15 10 16 11 18 12
Totals 35 0.0123 103 72 112 79 124 74 0.45 2640 10.6 2904 11.7 3168 12.7

Notes:
[1] Quantities shown do not provide for widening, waste from stockpile, or thickened edges.
[2] Quantities of asphalt shown are based on 60°F temperature. Recompute to the application temperature for the particular grade.
[3] The column “Basic Asphalt Used” is shown for the purpose of conversion to proper weights for the asphalt being used and does not imply that
the particular grade shown is required for the respective treatment.
[4] For stress-absorbing membrane (rubberized asphalt), increase asphalt by 25%.

Page 620-4 WSDOT Design Manual M 22-01.12

November 2015
Chapter 620 Design of Pavement Structure

Exhibit 620-4 Estimating: Base and Surfacing Typical Section Formulae and Example

WS

S1
d S

S2
Pavement Section Shoulder Section

WS = Shoulder Width (Varies 4 ft, 6 ft, 8 ft, 10 ft, 12 ft)

d = Depth of Section (Varies 0.05 ft to 2 ft)
S = Side Slope (H:V) (Varies 2:1, 3:1, 4:1, and 6:1)
S1 = Top Shoulder Slope (Varies -0.02 ft/ft or -0.05 ft/ft)
S2 = Bottom Shoulder Slope (Varies -0.02 ft/ft or -0.05 ft/ft)

Formula for Shoulder Section

Tons/mile = (A)(K) K=(5280/27)(1.85 tons/cy)

A
d  WS 1 / S  S1 2 S  WS2 1 / S  S 
21  SS 2 
1
2

Case 1 S1 = S = -0.02 ft/ft A

d  WS 1 / S  0.022 S  WS2 1 / S  0.02
21  0.02S 
2
2

Case 2 S1 = -0.02 ft/ft, S = -0.05 ft/ft A

 d  WS 1 / S  0.02 S WS2
2

 1 / S  0.02
21  0.05S 
2
2

Case 3 S1 = -0.05 ft/ft, S2 = -0.02 ft/ft A

d  WS 1 / S  0.052 S  WS2 1 / S  0.05 *

21  0.02S  2

Case 4 S1 = S2 = -0.05 ft/ft A

d  WS 1 / S  0.05 S  WS2 1 / S  0.05
2

21  0.05S  2
*Limit: Positive Values of A only when d = WS(0.03)

EXAMPLE: Shoulder Section

Given: Shoulder Width (WS) = 8 ft
Top Course = 0.25 ft
Base Course = 0.80 ft
Total Depth (d) = 1.05 ft
Side Slope (S) = 3:1
Shoulder Slope (S1) = -0.05
Subgrade Slope (S2) = -0.02
Depth 1.05 ft (Case 3) = 3,070 tons/mile
Top Course 0.25 ft (Case 4) = - 763 tons/mile
Base Course = 2,307 tons/mile
Top Course = 763 tons/mile
Base Course = 2,307 tons/mile

WSDOT Design Manual M 22-01.12 Page 620-5

November 2015
Design of Pavement Structure Chapter 620

Exhibit 620-5a Estimating: Base and Surfacing Quantities

Shoulder Section
Shldr. Side Quantity in Tons Per Mile*
Width Slope Case Surfacing Depth (ft)
Ws (ft) S:1 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50
1 73 148 226 304 385 468 553 639 728 818
2 171 251 333 417 504 592 682 774 869 965
2
3 N/A N/A 131 205 281 360 440 522 605 691
4 73 149 226 306 387 470 556 643 733 824
1 74 150 230 313 398 486 577 671 768 868
2 178 262 350 442 536 634 734 838 945 1056
3
3 N/A N/A 131 206 285 366 450 537 627 720
4 74 151 231 315 402 492 585 681 780 883
4
1 74 153 235 321 411 505 603 705 810 920
2 185 275 370 469 572 681 793 910 1032 1158
4
3 N/A N/A 131 208 288 373 461 554 650 750
4 75 154 237 326 418 516 617 724 834 950
1 75 157 245 339 439 545 658 776 901 1032
2 204 307 417 535 661 794 936 1085 1242 1406
6
3 N/A N/A 131 210 296 387 485 589 699 815
4 76 160 252 351 459 574 696 827 965 1111
1 109 221 334 449 566 685 806 929 1053 1180
2 325 444 565 688 812 939 1068 1199 1332 1467
2
3 N/A N/A N/A 239 349 461 575 691 809 929
4 110 221 335 450 568 687 809 933 1058 1186
1 110 223 339 457 579 703 830 961 1094 1230
2 338 462 590 722 856 994 1134 1278 1426 1576
3
3 N/A N/A N/A 239 350 464 581 701 824 949
4 110 223 340 460 583 709 838 970 1106 1245
6
1 110 225 343 466 592 722 856 994 1136 1282
2 352 483 619 760 905 1055 1209 1368 1531 1699
4
3 N/A N/A N/A 239 351 467 587 711 839 971
4 111 226 346 470 599 733 871 1013 1160 1311
1 112 229 353 483 620 762 911 1066 1227 1394
2 386 534 690 853 1025 1204 1391 1585 1788 1998
6
3 N/A N/A N/A 239 353 474 600 733 871 1016
4 112 233 360 496 640 791 950 1116 1291 1473
1 146 293 443 594 747 902 1059 1218 1379 1541
2 526 683 843 1004 1167 1333 1500 1670 1841 2015
2
3 N/A N/A N/A N/A 376 522 670 820 972 1125
4 146 293 443 595 749 904 1062 1222 1384 1548
1 146 295 447 602 760 920 1084 1250 1419 1591
2 546 711 879 1050 1224 1402 1583 1766 1954 2144
3
3 N/A N/A N/A N/A 376 523 673 825 981 1139
4 146 296 448 604 763 926 1091 1260 1432 1607
8
1 147 297 452 610 773 939 1109 1284 1462 1644
2 568 741 919 1101 1288 1479 1675 1875 2080 2290
4
3 N/A N/A N/A N/A 376 524 675 831 990 1153
4 147 298 454 615 780 950 1124 1302 1486 1673
1 148 302 462 628 801 979 1164 1355 1552 1755
2 622 816 1017 1226 1443 1668 1900 2140 2388 2643
6
3 N/A N/A N/A N/A 376 525 681 842 1009 1183
4 149 305 469 641 820 1008 1203 1406 1616 1835
*Tabulated quantities are based on compacted weight of 1.85 tons/yd 3

Page 620-6 WSDOT Design Manual M 22-01.12

November 2015
Chapter 620 Design of Pavement Structure

Exhibit 620-5b Estimating: Base and Surfacing Quantities

Shoulder Section
Shldr. Side Quantity in Tons Per Mile*
Width Slope Case Surfacing Depth (ft)
Ws (ft) S:1 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00
1 910 1004 1100 1198 1297 1399 1502 1608 1715 1824
2 1063 1163 1266 1370 1476 1585 1695 1807 1922 2038
2
3 779 868 960 1053 1148 1245 1344 1445 1548 1652
4 918 1013 1110 1210 1311 1415 1520 1628 1738 1849
1 971 1076 1185 1296 1410 1527 1647 1770 1896 2024
2 1169 1286 1406 1529 1655 1785 1918 2053 2193 2335
3
3 816 914 1016 1120 1228 1338 1451 1567 1686 1807
4 989 1098 1210 1326 1444 1566 1691 1820 1951 2086
4
1 1034 1151 1273 1398 1528 1661 1798 1939 2085 2234
2 1289 1424 1564 1708 1857 2010 2168 2330 2497 2668
4
3 855 963 1075 1191 1311 1435 1562 1694 1830 1969
4 1070 1194 1323 1456 1594 1737 1884 2035 2191 2352
1 1169 1312 1462 1617 1779 1947 2121 2301 2488 2680
2 1579 1759 1947 2142 2346 2557 2776 3002 3237 3479
6
3 937 1066 1200 1341 1488 1641 1800 1966 2138 2315
4 1265 1426 1596 1773 1957 2150 2350 2558 2774 2998
1 1308 1438 1570 1704 1840 1978 2117 2259 2402 2548
2 1603 1742 1883 2026 2171 2318 2467 2618 2771 2926
2
3 1050 1174 1299 1426 1555 1686 1819 1954 2090 2229
4 1315 1447 1581 1716 1854 1994 2135 2279 2425 2573
1 1369 1510 1655 1802 1953 2106 2262 2421 2583 2748
2 1729 1886 2046 2209 2376 2545 2718 2894 3073 3255
3
3 1078 1209 1343 1480 1620 1763 1909 2058 2209 2363
4 1387 1532 1681 1832 1987 2145 2306 2471 2638 2809
6
1 1432 1586 1743 1905 2070 2240 2413 2591 2772 2957
2 1871 2048 2229 2415 2606 2801 3000 3204 3412 3625
4
3 1106 1246 1389 1537 1688 1843 2003 2166 2333 2504
4 1467 1628 1793 1963 2137 2315 2499 2686 2878 3075
1 1567 1746 1932 2124 2322 2526 2736 2953 3175 3404
2 2215 2441 2674 2916 3164 3421 3685 3957 4237 4525
6
3 1167 1325 1488 1658 1833 2015 2203 2398 2598 2805
4 1663 1861 2066 2279 2500 2729 2965 3209 3461 3721
1 1706 1872 2040 2211 2383 2557 2732 2910 3090 3271
2 2190 2367 2547 2728 2912 3097 3285 3475 3666 3860
2
3 1281 1438 1597 1758 1921 2086 2253 2422 2592 2765
4 1713 1881 2051 2223 2397 2573 2751 2930 3112 3296
1 1766 1944 2125 2309 2495 2685 2877 3072 3271 3472
2 2338 2534 2734 2937 3144 3353 3566 3782 4001 4223
3
3 1300 1464 1631 1801 1974 2149 2328 2509 2693 2880
4 1785 1966 2151 2339 2530 2724 2921 3122 3326 3533
8
1 1830 2020 2214 2411 2613 2819 3028 3242 3459 3681
2 2504 2722 2945 3172 3404 3641 3882 4128 4378 4632
4
3 1320 1491 1666 1845 2028 2215 2405 2600 2799 3001
4 1865 2062 2263 2469 2679 2894 3114 3337 3566 3799
1 1965 2181 2402 2630 2864 3105 3351 3604 3863 4128
2 2907 3178 3457 3743 4038 4340 4650 4967 5292 5626
6
3 1363 1549 1741 1940 2144 2355 2572 2795 3024 3259
4 2061 2295 2536 2786 3043 3308 3580 3861 4149 4445
*Tabulated quantities are based on compacted weight of 1.85 tons/yd 3

WSDOT Design Manual M 22-01.12 Page 620-7

November 2015
Design of Pavement Structure Chapter 620

Exhibit 620-5c Estimating: Base and Surfacing Quantities

Shoulder Section

Shldr. Side Quantity in Tons Per Mile*

Width Slope Case Surfacing Depth (ft)
Ws (ft) S:1 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50
1 182 366 551 739 928 1119 1312 1507 1704 1903
2 773 969 1167 1367 1569 1773 1979 2187 2397 2609
2
3 N/A N/A N/A N/A N/A 543 724 908 1094 1281
4 182 366 552 740 930 1122 1315 1511 1709 1909
1 182 368 556 747 941 1137 1337 1539 1745 1953
2 802 1007 1215 1426 1640 1858 2079 2303 2530 2760
3
3 N/A N/A N/A N/A N/A 543 725 910 1098 1289
4 182 368 557 749 944 1143 1344 1549 1757 1968
10
1 183 370 560 755 954 1156 1363 1573 1787 2006
2 834 1049 1268 1492 1721 1954 2191 2433 2679 2930
4
3 N/A N/A N/A N/A N/A 543 726 912 1103 1298
4 183 371 563 760 961 1167 1377 1592 1811 2035
1 184 374 570 773 982 1196 1417 1644 1878 2117
2 913 1153 1399 1654 1916 2186 2464 2750 3043 3344
6
3 N/A N/A N/A N/A N/A 543 727 917 1113 1316
4 185 377 578 786 1001 1225 1456 1695 1942 2197
1 218 438 660 883 1109 1336 1566 1797 2030 2265
2 1066 1301 1537 1776 2016 2259 2504 2750 2999 3249
2
3 N/A N/A N/A N/A N/A N/A N/A 956 1175 1397
4 218 438 660 884 1110 1339 1569 1801 2035 2271
1 219 440 664 891 1121 1354 1590 1829 2071 2315
2 1106 1351 1599 1850 2104 2362 2623 2887 3154 3424
3
3 N/A N/A N/A N/A N/A N/A N/A 956 1177 1401
4 219 441 666 894 1125 1360 1598 1839 2083 2330
12
1 219 442 669 900 1134 1373 1616 1862 2113 2367
2 1151 1407 1668 1933 2203 2478 2757 3040 3328 3621
4
3 N/A N/A N/A N/A N/A N/A N/A 956 1179 1405
4 219 443 672 904 1142 1384 1630 1881 2137 2397
1 220 446 679 918 1162 1413 1671 1934 2203 2479
2 1259 1544 1836 2136 2444 2759 3083 3414 3752 4099
6
3 N/A N/A N/A N/A N/A N/A N/A 957 1182 1413
4 221 450 686 930 1182 1442 1709 1985 2268 2558
Pavement Section
Width WP (ft) 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50
11 199 398 597 796 995 1194 1393 1592 1791 1990
12 217 434 651 868 1085 1302 1519 1737 1954 2171
22 398 796 1194 1592 1990 2388 2786 3184 3582 3980
24 434 868 1302 1737 2171 2605 3039 3473 3907 4341
*Tabulated quantities are based on compacted weight of 1.85 tons/yd3

Page 620-8 WSDOT Design Manual M 22-01.12

November 2015
Chapter 620 Design of Pavement Structure

Exhibit 620-5d Estimating: Base and Surfacing Quantities

Shoulder Section

Shldr. Side Quantity in Tons Per Mile*

Width Slope Case Surfacing Depth (ft)
Ws (ft) S:1 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00
1 2104 2306 2511 2717 2925 3135 3347 3561 3777 3995
2 2823 3039 3257 3477 3699 3923 4149 4378 4608 4840
2
3 1471 1662 1855 2050 2247 2446 2646 2849 3053 3260
4 2111 2315 2521 2729 2939 3151 3366 3582 3800 4020
1 2164 2378 2595 2815 3038 3264 3492 3724 3958 4195
2 2994 3230 3470 3714 3960 4209 4462 4718 4977 5239
3
3 1483 1680 1880 2082 2288 2496 2707 2921 3138 3358
4 2183 2401 2621 2845 3072 3303 3536 3773 4013 4256
10
1 2228 2454 2684 2918 3156 3398 3643 3893 4147 4404
2 3186 3446 3710 3980 4253 4531 4814 5101 5393 5689
4
3 1496 1699 1905 2116 2330 2548 2770 2996 3227 3460
4 2263 2496 2734 2976 3222 3473 3729 3989 4253 4522
1 2363 2615 2873 3137 3407 3684 3966 4255 4550 4851
2 3653 3969 4294 4626 4965 5313 5668 6031 6402 6781
6
3 1524 1739 1960 2187 2420 2660 2906 3157 3415 3679
4 2459 2729 3007 3292 3585 3887 4195 4512 4836 5168
1 2502 2740 2981 3224 3468 3714 3962 4212 4464 4718
2 3502 3757 4013 4272 4533 4795 5060 5327 5596 5866
2
3 1620 1845 2072 2301 2532 2765 2999 3236 3474 3714
4 2509 2750 2992 3236 3482 3730 3981 4233 4487 4743
1 2562 2813 3066 3322 3581 3843 4107 4375 4645 4919
2 3698 3975 4255 4538 4824 5114 5406 5702 6001 6304
3
3 1627 1857 2089 2324 2562 2803 3047 3294 3544 3796
4 2581 2835 3092 3352 3615 3882 4151 4424 4700 4980
12
1 2626 2888 3154 3424 3698 3976 4258 4544 4834 5128
2 3918 4220 4526 4837 5152 5472 5796 6125 6458 6796
4
3 1635 1869 2107 2348 2594 2844 3098 3355 3617 3882
4 2661 2930 3204 3482 3765 4052 4344 4640 4941 5246
1 2761 3049 3343 3643 3950 4262 4581 4906 5237 5575
2 4453 4815 5185 5562 5948 6341 6742 7150 7566 7991
6
3 1651 1894 2144 2400 2662 2930 3205 3485 3772 4065
4 2857 3163 3477 3799 4128 4465 4810 5163 5524 5892
Pavement Section
Width WP (ft) 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00
11 2189 2388 2587 2786 2985 3184 3383 3582 3781 3980
12 2388 2605 2822 3039 3256 3473 3690 3907 4124 4341
22 4378 4775 5173 5571 5969 6367 6765 7163 7561 7959
24 4775 5210 5644 6078 6512 6946 7380 7814 8249 8683
*Tabulated quantities are based on compacted weight of 1.85 tons/yd 3

WSDOT Design Manual M 22-01.12 Page 620-9

November 2015
Design of Pavement Structure Chapter 620

Exhibit 620-5e Estimating: Base and Surfacing Quantities

Shoulder Section
Quantity in Tons Per Mile*
Shldr. Side
Width Slope Case Surfacing Depth (ft)
Ws (ft) S:1
1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50
1 1935 2048 2163 2279 2398 2518 2640 2765 2891 3019
2 2157 2277 2399 2524 2650 2779 2909 3042 3176 3312
2
3 1759 1867 1977 2089 2203 2319 2437 2557 2678 2802
4 1963 2078 2196 2315 2437 2561 2686 2814 2943 3075
1 2156 2290 2428 2568 2711 2857 3006 3157 3312 3470
2 2480 2629 2781 2936 3094 3255 3420 3588 3759 3933
3
3 1932 2059 2190 2323 2459 2598 2740 2885 3033 3183
4 2223 2364 2509 2656 2806 2960 3117 3277 3441 3607
4
1 2387 2543 2704 2869 3038 3210 3387 3567 3752 3940
2 2844 3025 3210 3399 3593 3792 3995 4202 4415 4631
4
3 2113 2260 2412 2567 2726 2890 3057 3228 3403 3582
4 2517 2686 2860 3039 3222 3410 3602 3799 4000 4206
1 2879 3084 3295 3513 3736 3966 4201 4443 4691 4946
2 3729 3986 4252 4525 4806 5094 5391 5695 6007 6327
6
3 2499 2689 2886 3088 3297 3512 3733 3960 4193 4433
4 3229 3468 3715 3969 4232 4502 4779 5065 5358 5659
1 2695 2844 2995 3147 3302 3459 3617 3778 3940 4104
2 3083 3242 3403 3566 3731 3898 4067 4238 4411 4586
2
3 2369 2511 2655 2802 2949 3099 3251 3404 3560 3717
4 2722 2874 3028 3184 3341 3501 3663 3827 3993 4160
1 2916 3086 3260 3436 3615 3798 3983 4170 4361 4555
2 3440 3629 3821 4016 4214 4416 4620 4828 5039 5253
3
3 2521 2681 2844 3010 3179 3351 3525 3703 3883 4067
4 2983 3160 3341 3524 3711 3901 4094 4290 4490 4692
6
1 3146 3339 3536 3737 3942 4151 4364 4580 4801 5026
2 3843 4065 4291 4523 4758 4998 5243 5492 5746 6004
4
3 2679 2858 3041 3228 3418 3613 3812 4014 4221 4431
4 3276 3482 3692 3907 4127 4350 4579 4812 5049 5291
1 3639 3880 4127 4381 4640 4906 5178 5456 5741 6031
2 4820 5123 5434 5753 6079 6413 6755 7105 7462 7827
6
3 3017 3236 3461 3693 3930 4174 4423 4679 4941 5210
4 3989 4264 4547 4837 5136 5442 5756 6078 6407 6745
1 3454 3640 3827 4016 4207 4399 4594 4791 4989 5189
2 4055 4253 4452 4654 4858 5063 5271 5480 5692 5906
2
3 2939 3115 3293 3473 3655 3839 4024 4212 4401 4592
4 3482 3670 3860 4052 4246 4442 4640 4840 5042 5246
1 3675 3882 4092 4304 4520 4738 4959 5183 5410 5640
2 4449 4677 4909 5144 5382 5624 5869 6116 6367 6622
3
3 3070 3263 3459 3658 3859 4064 4271 4481 4695 4911
4 3743 3956 4173 4392 4615 4841 5071 5303 5539 5778
8
1 3906 4135 4368 4606 4847 5092 5341 5593 5850 6111
2 4891 5155 5423 5696 5973 6255 6541 6832 7127 7427
4
3 3208 3418 3632 3851 4073 4299 4529 4763 5001 5243
4 4036 4278 4524 4775 5031 5291 5556 5825 6098 6376
1 4399 4676 4959 5249 5545 5847 6155 6469 6790 7116
2 5966 6315 6671 7035 7407 7787 8174 8569 8972 9383
6
3 3501 3749 4002 4262 4529 4801 5079 5364 5655 5952
4 4748 5060 5379 5706 6040 6383 6733 7091 7456 7830
*Tabulated quantities are based on compacted weight of 1.85 tons/yd3

Page 620-10 WSDOT Design Manual M 22-01.12

November 2015
Chapter 620 Design of Pavement Structure

Exhibit 620-5f Estimating: Base and Surfacing Quantities

Shoulder Section
Shldr. Side Quantity in Tons Per Mile*
Width Slope Case Surfacing Depth (ft)
Ws (ft) S:1 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 2.00
1 3148 3280 3414 3549 3687 3826 3967 4110 4255 4402
2 3451 3591 3734 3878 4025 4173 4324 4477 4631 4788
2
3 2927 3054 3183 3314 3447 3582 3718 3857 3997 4139
4 3209 3344 3482 3622 3763 3907 4053 4201 4350 4502
1 3630 3793 3959 4129 4300 4475 4653 4834 5017 5203
2 4110 4291 4475 4662 4852 5045 5242 5441 5644 5850
3
3 3337 3493 3652 3814 3979 4147 4318 4492 4668 4848
4 3777 3950 4126 4305 4488 4673 4862 5054 5250 5448
4
1 4133 4329 4529 4733 4941 5153 5369 5589 5812 6040
2 4852 5078 5308 5543 5782 6026 6274 6527 6784 7046
4
3 3764 3951 4142 4337 4535 4738 4944 5155 5369 5587
4 4416 4631 4850 5074 5302 5535 5773 6015 6261 6512
1 5206 5473 5745 6024 6310 6601 6898 7202 7512 7828
2 6654 6989 7332 7683 8041 8407 8781 9163 9552 9950
6
3 4678 4930 5188 5452 5722 5999 6282 6570 6865 7166
4 5968 6285 6609 6941 7281 7628 7984 8347 8718 9096
1 4270 4438 4608 4779 4953 5128 5306 5485 5666 5849
2 4763 4942 5123 5306 5491 5678 5868 6059 6252 6447
2
3 3876 4038 4201 4365 4532 4701 4871 5044 5218 5394
4 4330 4502 4676 4852 5030 5210 5391 5575 5761 5949
1 4752 4951 5153 5359 5567 5778 5992 6208 6428 6651
2 5471 5691 5915 6142 6372 6605 6842 7082 7325 7571
3
3 4253 4442 4634 4829 5026 5227 5430 5637 5846 6058
4 4898 5107 5320 5535 5754 5976 6201 6429 6660 6895
6
1 5254 5486 5723 5963 6207 6455 6707 6963 7223 7487
2 6267 6534 6806 7082 7363 7648 7938 8233 8532 8835
4
3 4645 4864 5086 5312 5542 5776 6014 6256 6501 6751
4 5537 5788 6044 6304 6569 6838 7111 7389 7672 7959
1 6328 6630 6939 7254 7576 7903 8237 8577 8923 9275
2 8200 8581 8969 9365 9769 10181 10600 11028 11463 11905
6
3 5484 5765 6051 6344 6643 6949 7260 7578 7901 8231
4 7090 7442 7803 8171 8547 8931 9322 9721 10128 10543
1 5391 5595 5801 6009 6219 6431 6644 6859 7077 7296
2 6121 6339 6559 6780 7004 7230 7457 7687 7919 8153
2
3 4785 4980 5177 5376 5577 5779 5984 6190 6398 6608
4 5452 5660 5870 6082 6296 6512 6730 6950 7172 7396
1 5873 6109 6347 6589 6833 7080 7330 7583 7839 8098
2 6879 7140 7403 7670 7940 8214 8490 8770 9053 9339
3
3 5129 5351 5576 5803 6034 6267 6503 6743 6985 7229
4 6020 6265 6514 6765 7020 7278 7539 7804 8071 8342
8
1 6376 6644 6917 7193 7473 7758 8046 8338 8634 8934
2 7731 8040 8354 8671 8994 9321 9652 9988 10329 10674
4
3 5488 5738 5992 6249 6511 6776 7046 7319 7596 7877
4 6659 6946 7238 7534 7835 8140 8450 8764 9083 9406
1 7449 7788 8133 8485 8842 9206 9575 9951 10333 10722
2 9801 10227 10661 11103 11552 12009 12474 12947 13427 13915
6
3 6255 6565 6880 7202 7530 7864 8204 8550 8903 9262
4 8211 8600 8997 9401 9813 10233 10661 11096 11539 11990
*Tabulated quantities are based on compacted weight of 1.85 tons/yd3

WSDOT Design Manual M 22-01.12 Page 620-11

November 2015
Design of Pavement Structure Chapter 620

Exhibit 620-5g Estimating: Base and Surfacing Quantities

Shoulder Section

Shldr. Side Quantity in Tons Per Mile*

Width Slope Case Surfacing Depth (ft)
Ws (ft) S:1 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50
1 4214 4436 4659 4884 5111 5340 5571 5804 6038 6275
2 5074 5310 5548 5788 6031 6275 6521 6769 7019 7272
2
3 3468 3678 3890 4104 4320 4537 4757 4978 5201 5427
4 4242 4466 4692 4920 5150 5382 5617 5853 6091 6331
1 4435 4678 4924 5173 5424 5679 5936 6196 6460 6726
2 5505 5774 6045 6320 6599 6880 7165 7453 7744 8038
3
3 3581 3806 4035 4266 4501 4738 4978 5221 5467 5715
4 4503 4752 5005 5261 5520 5782 6048 6316 6588 6863
10
1 4666 4931 5201 5474 5751 6032 6317 6606 6899 7196
2 5990 6295 6605 6919 7238 7561 7889 8221 8558 8900
4
3 3698 3940 4186 4436 4689 4947 5208 5474 5743 6017
4 4796 5074 5357 5644 5935 6232 6532 6838 7147 7462
1 5158 5472 5792 6117 6449 6787 7132 7482 7839 8202
2 7167 7561 7963 8373 8790 9215 9648 10088 10537 10993
6
3 3950 4226 4509 4798 5093 5394 5701 6015 6334 6660
4 5508 5856 6211 6574 6945 7323 7710 8104 8506 8915
1 4974 5231 5491 5752 6015 6281 6548 6816 7087 7360
2 6139 6414 6691 6969 7250 7533 7818 8104 8393 8684
2
3 3956 4200 4446 4694 4944 5195 5449 5704 5961 6220
4 5002 5262 5524 5788 6055 6323 6593 6866 7140 7416
1 5195 5474 5756 6041 6329 6619 6913 7209 7509 7811
2 6609 6918 7230 7545 7863 8184 8509 8837 9168 9502
3
3 4052 4310 4571 4836 5103 5372 5645 5921 6199 6481
4 5262 5548 5837 6129 6424 6723 7024 7329 7637 7948
12
1 5425 5727 6033 6342 6656 6973 7294 7619 7948 8282
2 7138 7485 7836 8192 8553 8917 9287 9661 10039 10422
4
3 4151 4425 4702 4983 5268 5557 5850 6147 6448 6753
4 5556 5870 6189 6512 6840 7172 7509 7851 8197 8547
1 5918 6268 6624 6986 7354 7728 8109 8495 8888 9287
2 8422 8862 9309 9764 10227 10698 11176 11662 12156 12657
6
3 4364 4669 4981 5298 5622 5952 6288 6630 6979 7333
4 6268 6652 7043 7442 7849 8264 8687 9117 9555 10001
Pavement Section
Width WP (ft) 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50
11 4179 4378 4576 4775 4974 5173 5372 5571 5770 5969
12 4558 4775 4993 5210 5427 5644 5861 6078 6295 6512
22 8357 8755 9153 9551 9949 10347 10745 11143 11541 11939
24 9117 9551 9985 10419 10853 11287 11722 12156 12590 13024
*Tabulated quantities are based on compacted weight of 1.85 tons/yd 3

Page 620-12 WSDOT Design Manual M 22-01.12

November 2015
Chapter 620 Design of Pavement Structure

Exhibit 620-5h Estimating: Base and Surfacing Quantities

Shoulder Section

Shldr. Side Quantity in Tons Per Mile*

Width Slope Case Surfacing Depth (ft)
Ws (ft) S:1 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 2.00
1 6513 6753 6995 7239 7485 7733 7983 8234 8488 8743
2 7526 7782 8041 8301 8563 8827 9094 9362 9632 9905
2
3 5654 5883 6113 6346 6581 6817 7056 7296 7538 7782
4 6573 6818 7064 7312 7562 7814 8069 8325 8583 8843
1 6995 7266 7541 7819 8099 8382 8669 8958 9250 9545
2 8335 8636 8940 9247 9557 9870 10187 10506 10829 11156
3
3 5967 6221 6479 6739 7002 7268 7537 7809 8084 8361
4 7141 7423 7707 7995 8286 8581 8878 9179 9482 9789
10
1 7497 7802 8111 8423 8740 9060 9385 9713 10045 10381
2 9246 9596 9951 10311 10675 11043 11416 11794 12176 12563
4
3 6294 6575 6860 7149 7442 7739 8040 8344 8653 8966
4 7780 8104 8432 8764 9101 9442 9788 10139 10494 10853
1 8571 8946 9327 9715 10108 10508 10914 11326 11744 12169
2 11457 11928 12408 12895 13390 13892 14403 14921 15447 15980
6
3 6992 7330 7674 8025 8382 8744 9113 9488 9870 10257
4 9333 9758 10191 10631 11079 11536 11999 12471 12950 13437
1 7634 7911 8189 8469 8751 9035 9321 9609 9899 10190
2 8977 9272 9569 9868 10168 10471 10776 11083 11392 11703
2
3 6481 6744 7009 7276 7544 7814 8087 8361 8637 8915
4 7695 7975 8258 8542 8828 9117 9407 9700 9994 10291
1 8116 8424 8735 9049 9365 9685 10007 10333 10661 10992
2 9840 10180 10524 10871 11221 11575 11931 12291 12654 13020
3
3 6765 7052 7342 7635 7931 8230 8532 8836 9144 9454
4 8263 8581 8901 9225 9553 9883 10216 10553 10893 11236
12
1 8619 8960 9304 9653 10006 10363 10723 11088 11456 11829
2 10810 11202 11599 12000 12405 12816 13230 13650 14073 14502
4
3 7061 7374 7691 8011 8335 8664 8996 9332 9672 10017
4 8902 9262 9626 9994 10367 10745 11127 11514 11905 12300
1 9692 10103 10521 10945 11374 11810 12253 12701 13155 13616
2 13167 13684 14209 14741 15282 15830 16386 16949 17521 18100
6
3 7694 8061 8434 8813 9199 9590 9988 10392 10802 11218
4 10454 10915 11384 11861 12346 12838 13338 13846 14361 14885
Pavement Section
Width WP (ft) 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 2.00
11 6168 6367 6566 6765 6964 7163 7362 7561 7760 7959
12 6729 6946 7163 7380 7597 7814 8031 8249 8466 8683
22 12337 12735 13133 13530 13928 14326 1472 14122 15520 15918
24 13458 13892 14326 14761 15195 15629 16063 16497 16931 17365
*Tabulated quantities are based on compacted weight of 1.85 tons/yd 3

WSDOT Design Manual M 22-01.12 Page 620-13

November 2015
Design of Pavement Structure Chapter 620

Page 620-14 WSDOT Design Manual M 22-01.12

November 2015
Chapter 630 Geosynthetics
630.01 General
630.02 References
630.03 Geosynthetic Types and Characteristics
630.04 Geosynthetic Function Definitions and Applications
630.05 Design Approach for Geosynthetics
630.06 Design Responsibility
630.07 Documentation

630.01 General
Geosynthetics include a variety of manufactured products that are used by the
Washington State Department of Transportation (WSDOT) in drainage, earthwork,
erosion control, and soil reinforcement applications.
The following geosynthetic applications are addressed in the Standard Specifications
for Road, Bridge, and Municipal Construction (Standard Specifications):
• Low survivability underground drainage
• Moderate survivability underground drainage
• Separation
• Soil stabilization
• Moderate survivability permanent erosion control
• High survivability permanent erosion control
• Ditch lining
• Temporary silt fence
The Standard Specifications addresses geosynthetic properties as well as installation
requirements and are not site-specific. The geosynthetic properties provided are
based on the range of soil conditions likely to be encountered in Washington for the
applications defined. Other applications, such as prefabricated edge drains, pond
liners, and geotextile retaining walls, are currently handled by special provision.
Design responsibilities are discussed in 630.05 and illustrated in Exhibits 630-4
and 630-5.
This chapter does not address applications where geosynthetics are used to help
establish vegetation through temporary prevention of erosion (vegetation mats).

630.02 References
(1) Design Guidance
Highway Runoff Manual, M 31-15, WSDOT
Hydraulics Manual, M 23-03, WSDOT
Plans Preparation Manual, M 22-31, WSDOT
Standard Specifications for Road, Bridge, and Municipal Construction (Standard
Specifications), M 41-10, WSDOT
WSDOT Pavement Policy, available at the Pavements website:
 www.wsdot.wa.gov/business/materialslab/pavements/default.htm

WSDOT Design Manual M 22-01.10 Page 630-1

July 2013
Geosynthetics Chapter 630

630.03 Geosynthetic Types and Characteristics

Geosynthetics include woven and nonwoven geotextiles, geogrids, geonets,
geomembranes, and geocomposites. (Examples of the various types of geosynthetics
are provided in Exhibit 630-6.) Terms used in the past for these construction materials
include fabrics, filter fabric, or filter cloth, which are for the most part synonymous
with the newer term geotextile.
(1) Definitions
Definitions of the geosynthetic types are as follows:
(a) Woven Geotextiles
Slit polymer tapes, monofilament fibers, fibrillated yarns, or multifilament yarns
simply woven into a mat. Woven geotextiles generally have relatively high
strength and stiffness and, except for the monofilament wovens, relatively poor
drainage characteristics.
(b) Nonwoven Geotextiles
A sheet of continuous or staple fibers entangled randomly into a felt for needle-
punched nonwovens and pressed and melted together at the fiber contact points
for heat-bonded nonwovens. Nonwoven geotextiles tend to have low-to-medium
strength and stiffness with high elongation at failure and relatively good drainage
characteristics. The high elongation characteristic gives them superior ability to
deform around stones and sticks.
(c) Geogrids
A polymer grid mat constructed either of coated yarns or a punched and stretched
polymer sheet. Geogrids usually have high strength and stiffness and are used
primarily for soil reinforcement.
(d) Geonets
Similar to geogrids, but typically lighter weight and weaker, with smaller mesh
openings. Geonets are used in light reinforcement applications or are combined
with drainage geotextiles to form a drainage structure.
(e) Geomembranes
Impervious polymer sheets that are typically used to line ponds or landfills.
In some cases, geomembranes are placed over moisture-sensitive swelling
clays to control moisture.
(f) Geocomposites
Prefabricated edge drains, wall drains, and sheet drains that typically consist of
a cuspated or dimpled polyethylene drainage core wrapped in a geotextile. The
geotextile wrap keeps the core clean so that water can freely flow through the
drainage core, which acts as a conduit. Prefabricated edge drains are used in
place of shallow geotextile-wrapped trench drains at the edges of the roadway
to provide subgrade and base drainage. Wall drains and sheet drains are typically
placed between the back of the wall and the soil to drain the soil retained by
the wall.

Page 630-2 WSDOT Design Manual M 22-01.05

June 2009
Chapter 630 Geosynthetics

630.04 Geosynthetic Function Definitions and Applications

The function of the geosynthetic varies with the application. (See Exhibit 630-7 for
examples of the various applications.) The geosynthetic must be designed with its
application function(s) in mind. Typical geosynthetic functions include filtration,
drainage, separation, reinforcement, and erosion control.
(1) Definitions
Definitions of these functions and examples of their dominant applications are
as follows:
(a) Geosynthetic Filtration
The passage of water through the geosynthetic relatively unimpeded
(permeability or permittivity) without allowing passage of soil through
the geosynthetic (retention). This is the primary function of geotextiles in
underground drainage applications.
(b) Drainage
The carrying of water in the plane of the geosynthetic as a conduit
(transmissivity) is a primary function of geocomposite drains. In some cases,
the function includes thick, nonwoven needle-punched geotextiles placed in
underground drainage applications where water must be transported away from
a given location by the geosynthetic itself.
(c) Separation
The prevention of the mixing of two dissimilar materials. This is a primary
function of geotextiles placed between a fine-grained subgrade and a granular
base course beneath a roadway.
(d) Reinforcement
The strengthening of a soil mass by the inclusion of elements (geosynthetics)
that have tensile strength. This is the primary function of high-strength
geotextiles and geogrids in geosynthetic reinforced wall or slope applications,
or in roadways placed over very soft subgrade soils that are inadequate to support
the weight of the construction equipment or even the embankment itself.
(e) Geosynthetic Erosion Control
The minimizing of surficial soil particle movement due to the flow of water over
the surface of bare soil or due to the disturbance of soil caused by construction
activities under or near bodies of water. This is the primary function of
geotextiles used as silt fences or placed beneath riprap or other stones on soil
slopes. Silt fences keep eroded soil particles on the construction site, whereas
geotextiles placed beneath riprap or other stones on soil slopes prevent erosion
from taking place at all. In general, the permanent erosion control methods
described in this chapter are only used where more natural means (like the use
of biodegradable vegetation mats to establish vegetation to prevent erosion)
are not feasible.
These functions control some of the geosynthetic properties, such as
apparent opening size (AOS) and permittivity, and in some cases load-
strain characteristics.

WSDOT Design Manual M 22-01.05 Page 630-3

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Geosynthetics Chapter 630

The application will also affect the geosynthetic installation conditions. These
installation conditions influence the remaining geosynthetic properties needed,
based on the survivability level required.
(f) Geosynthetic Survivability
The ability of the geosynthetic to resist installation conditions without significant
damage, such that the geosynthetic can function as intended. Survivability affects
the strength properties of the geosynthetic required.

630.05 Design Approach for Geosynthetics

The following questions must be answered to complete a geosynthetic design:
• Is a geosynthetic really needed?
• What geosynthetic properties will ensure the geosynthetic functions as intended?
• Where should the geosynthetic be located?
• Will maintenance of the geosynthetic, or the structure of which it is a part,
be needed? If so, how will it be maintained?
The site conditions and purpose for the geotextile are reviewed to determine whether
or not a geotextile is needed.
• For most drainage, separation, soil stabilization, permanent erosion control, and
silt fence applications, if a geotextile is needed, the geotextile properties in the
Standard Specifications can be used.
• In some situations where soil conditions are especially troublesome or in critical
or high-risk applications, a project-specific design may be needed.
• The location of the geosynthetic will depend on how it is intended to function.
(See Exhibit 630-7 for examples.)
• Consider the flow path of any groundwater or surface water when locating and
selecting the geotextile to be used. For example, in permanent erosion control
applications, water may flow to the geotextile from the existing ground as well
as from the surface through wave action, stream flow, or overland sheet flow.
For saturated fine sandy or silty subgrades, water must be able to flow from the
subgrade through the geotextile soil stabilization layer during the pumping action
caused by traffic loads.
Background information and the answers to each of these questions, or at least
guidance to obtaining the answers to these questions, are provided for each of the
following Standard Specifications applications:

(1) Underground Drainage: Low and Moderate Survivability

Geotextiles used for underground drainage must provide filtration to allow water to
reach the drain aggregate without allowing the aggregate to be contaminated by finer
soil particles.
Geotextile filtration properties are a function of the soil type. For underground
drainage applications, if the subgrade soil is relatively clean gravel or coarse sand,
a geotextile is probably not required. At issue is whether or not there are enough fines
in the surrounding soil to eventually clog the drain rock or drain pipe if unrestricted
flow toward the drain is allowed.

Page 630-4 WSDOT Design Manual M 22-01.05

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Chapter 630 Geosynthetics

To approximately match the geotextile filtration properties to various soil types,

specifications for three classes of Construction Geotextile for Underground Drainage
are available in the Standard Specifications. For underground drainage applications,
use the gradation of the soil, specifically the percent by weight passing the #200
sieve, to select the drainage geotextile class required. Base your selection of the
appropriate class of geotextile on Exhibit 630-1.
Percent Passing
Geotextile Class
the #200 Sieve
Less than 15% A
15% to 50% B
Greater than 50% C

Selection Criteria for Geotextile Class

Exhibit 630-1

Obtain soil samples for geotextile underdrain design every 300 feet along the
roadway alignment, using hand holes, and at major soil type transitions. This may
be spread to every 1000 feet if the soil conditions appear to be uniform. Use existing
soil data where feasible instead of taking new soil samples.
If soil conditions vary widely along the alignment where underground drainage
geotextile is anticipated, different classes of drainage geotextile may be required for
specific sections of a continuous system.
Strength properties for the underground drainage geotextile depend on the
survivability level required to resist installation stresses.
Low survivability designates that the installation stresses placed on the geotextile
will be relatively low, requiring only moderate geotextile strength to resist potentially
damaging installation conditions. Examples of low survivability level underground
drainage applications include:
• Trench drains.
• Drains placed behind walls or other structures to drain the backfill.
• A geotextile filter sheet placed behind a gabion wall to prevent fines from
being washed through the gabion wall face. Trench depths, or the height of the
geotextile filter sheet behind gabion walls, must be less than or equal to 6 feet for
the low survivability level.
In moderate survivability applications, significant installation stresses may occur,
requiring higher geotextile strength. Examples of the moderate survivability
application include:
• Trench drains with a depth of greater than 6 feet.
• A geotextile filter sheet behind a gabion wall with a height greater than 6 feet.
• Any area drain.
An area drain is defined as a geotextile placed over or under a horizontal-to-
moderately sloping (1.5H:1V or flatter slope) layer of drainage aggregate. Examples
of area drains include:
• Drainage layers over cut-and-cover tunnels.
• Rock buttress drainage.

WSDOT Design Manual M 22-01.05 Page 630-5

June 2009
Geosynthetics Chapter 630

• Permeable base beneath highway pavement (see the WSDOT Pavement Policy
for additional information on permeable bases).
• A parking lot drainage layer.
Note that pipe wrapping (the geotextile is wrapped around the surface of the pipe)
is not included as an underground drainage application.
Locate the geotextile such that it will function as intended. For example, if the
objective is to keep the drainage aggregate surrounding a drain pipe clean, locate
the geotextile so that it completely separates the drainage aggregate from more silty
surrounding soils, which may include native soils as well as relatively silty roadway
base or fill materials.
Consider the flow path of any groundwater or surface water when locating
the geotextile.
The flow path from the geotextile, as part of the groundwater drainage, is typically
directed to a surface water conveyance system. Design of surface water conveyance
is guided by the Hydraulics Manual. The surface water conveyance must be low
enough to prevent backflow and charging of the groundwater drainage—typically,
by matching inverts of groundwater drainage to crowns of surface water conveyance
pipes. A 1-foot allowance is usually applied when connecting to open water
or ditches.

(2) Separation
Geotextile used for separation must prevent penetration of relatively fine grained
subgrade soil into the ballast or other roadway or parking lot surfacing material
to prevent contamination of the surfacing material (the separation function). This
application may also apply to situations other than beneath roadway or parking
lot surfacing where it is not necessary for water to drain through the geotextile
unimpeded (filtration), but where separation of two dissimilar materials is required.
Separation geotextile should only be used in roadway applications where
the subgrade is can be prepared and compacted as required in the Standard
Specifications, but without removal and replacement of the subgrade soil with
granular material. Such removal and replacement defeats the purpose of the
geotextile separator.
Separation geotextile placed beneath roadway surfacing is feasible if the subgrade
resilient modulus is greater than 5,800 psi and if a saturated fine sandy, silty, or
clayey subgrade is not likely to be present. Note that the feasibility of separation
geotextile may be dependent on the time of year and weather conditions expected
when the geotextile is to be installed.
For separation applications, a geotextile is not needed if the subgrade is dense
and granular (silty sands and gravels), but is not saturated fine sands. In general,
a separation geotextile is not needed if the subgrade resilient modulus is greater
than 15,000 psi.

(3) Soil Stabilization

Geotextile used for soil stabilization must function as a separator, a filtration layer,
and (to a minor extent) a reinforcement layer. This application is similar to the
separation application, except the subgrade is anticipated to be softer and wetter than
in the separation application.

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Chapter 630 Geosynthetics

Soil stabilization geotextile is used in roadway applications if the subgrade is too soft
and wet to be prepared and compacted as required in the Standard Specifications. Soil
stabilization geotextile is placed directly on the soft subgrade material, even if some
overexcavation of the subgrade is performed. Backfill to replace the overexcavated
subgrade is not placed below the geotextile soil stabilization layer, as this would
defeat the purpose of the geotextile.
Anticipate the need for soil stabilization geotextile if the subgrade resilient modulus
is less than or equal to 5,800 psi, or if a saturated fine sandy, silty, or clayey subgrade
is likely to be present.
Consider the flow path of any groundwater or surface water when locating the soil
stabilization geotextile and when selecting the geotextile to be used. For saturated
fine sandy or silty subgrades, water must be able to flow from the subgrade
through the geotextile soil stabilization layer during the pumping action caused
by traffic loads.
Even if the subgrade is not anticipated to be saturated based on available data, if the
subgrade is silty or clayey and it is anticipated that the geotextile will be installed
during prolonged wet weather, a soil stabilization geotextile may still be needed.
Soil stabilization geotextile should not be used for roadway fills greater than 5 feet
high or when extremely soft and wet silt, clay, or peat is anticipated at the subgrade
level (for example, the deposits encountered in wetlands). In such cases, the
reinforcement function becomes more dominant, requiring a site-specific design.

(4) Permanent Erosion Control: Moderate and High Survivability

The primary function of geotextile used for permanent erosion control is to protect
the soil beneath it from erosion due to water flowing over the protected soil.
The need for a permanent erosion control geotextile depends on the type and
magnitude of water flow over the soil being considered for protection, the soil type in
terms of its erodability, and the type and amount of vegetative cover present (see the
Highway Runoff Manual).
The source of flowing water could be streams, constructed channels, wave action,
or runoff. Water may also flow from the soil behind the geotextile depending on the
groundwater level.
If groundwater cannot escape through the geotextile, an erosion control system
failure termed ballooning (resulting from water pressure buildup behind the
geotextile) or soil piping could occur. Therefore, the geotextile must have good
filtration characteristics.
Three classes of permanent erosion control geotextile are available to approximately
match geotextile filtration characteristics to the soil. In order to select the drainage
geotextile class, determine the gradation of the soil, specifically the percent by weight
passing the #200 sieve. Base selection of the appropriate class of geotextile on
Exhibit 630-1.
A minimal amount of soil sampling and testing is needed to determine the geotextile
class required. Permanent erosion control geotextile generally does not extend
along the roadway alignment for significant distances as does underground drainage
geotextile. One soil sample per permanent erosion control location is sufficient. If
multiple erosion control locations are anticipated along a roadway alignment, soil
sampling requirements for underground drainage can be applied.

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Geosynthetics Chapter 630

If soil conditions vary widely along the alignment where permanent erosion control
geotextile is anticipated, different classes of erosion control geotextile may be
required for specific sections of a continuous system.
Examples of the permanent erosion control application are the placement of
geotextile beneath riprap or gabions along drainage channels, shorelines, and
waterways; around bridge piers; and under slope protection for highway cut or
fill slopes.
If a moderate survivability geotextile is to be used, the geotextile must be protected
by a 12-inch aggregate cushion and be placed on slopes of 2H:1V or flatter to keep
installation stresses to a relatively low level. Large stones can cause significant
damage to a moderate survivability geotextile if the geotextile is not protected in
this manner. If these conditions are not met, then a high survivability erosion control
geotextile must be used.

(5) Ditch Lining

The primary function of the geotextile in a ditch lining application is to protect the
soil beneath it from erosion. This ditch lining application is limited to constructed
ditches less than 16 feet wide at the top with side slopes of 2H:1V or flatter. If
the ditch does not meet these requirements, then permanent erosion control, with
moderate or high survivability geotextile, must be used. It is assumed that only
quarry spall-sized stones or smaller will be placed on the geotextile, so only a
moderate survivability geotextile will be required.
Filtration is not a significant function in this application. Since the ditch is relatively
shallow, it is expected that the main water source will be the water carried by the
ditch, and little water will pass through the geotextile.
Another application with a similar geotextile function is the placement of geotextile
below culvert outlets to prevent erosion at the outlet.

(6) Temporary Silt Fence

The primary function of geotextile used in a temporary silt fence is to prevent eroded
material from being transported away from the construction site by runoff water. The
silt fence acts primarily as a temporary dam and secondarily as a filter.
In some cases, depending on the topography, the silt fence may also function as a
barrier to direct flow to low areas at the bottom of swales where the water can be
collected and temporarily ponded. It is desirable to avoid the barrier function as much
as possible, as silt fences are best suited to intercepting sheet flow rather than the
concentrated flows that would occur in swales or intermittent drainage channels.
To function as intended, the silt fence should have a low enough permeability to
allow the water to be temporarily retained behind the fence, allowing suspended soil
particles in the water to settle to the ground. If the retention time is too long, or if
the flow rate of water is too high, the silt fence could be overtopped, thus allowing
silt-laden water to escape. Therefore, a minimal amount of water must be able to flow
through the fence at all times.
Temporary water ponding is considered the primary method of silt removal and the
filtration capabilities of the fence are the second line of defense. However, removal
of silt-sized particles from the water directly by the geotextile creates severe filtration
conditions for the geotextile, forcing the geotextile to either blind or allow the fines to

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Chapter 630 Geosynthetics

pipe through the geotextile. (Blinding is the coating of the geotextile surface with soil
particles such that the openings are effectively plugged.) If the geotextile openings
(AOS) are designed to be small enough to capture most of the suspended soil
particles, the geotextile will likely blind, reducing the permeability enough to allow
water to overtop the fence. Therefore, it is best to allow some geotextile openings
that are large enough to allow the silt-sized particles to easily pass through. Even if
some silt particles pass through the fence, the water flow rate below the fence will be
decreased and the volume of silt-laden water passing through the geotextile is likely
to be relatively small and the water is partially filtered.
The geotextile apparent opening size (AOS) and permittivity are typically used
to specify the filtration performance of geotextiles. The geotextile function in silt
fence applications is more complex than this and AOS and permittivity do not relate
directly to how well a silt fence will perform. However, nominal values of AOS and
permittivity can be specified such that the types of geotextile products known to
perform satisfactorily in this application are selected. These values are provided in
the Standard Specifications.
The source of load on the geotextile is from silt buildup at the fence and water
ponding. The amount of strength required to resist this load depends on whether or
not the geotextile is supported with a wire or polymer grid mesh between the fence
posts. Obviously, unsupported geotextile must have greater strength than supported
geotextile. If the strength of the geotextile or its support system is inadequate, the
silt fence could fail. Furthermore, unsupported geotextile must have enough stiffness
that it does not deform excessively and allow silt-laden water to go over the top of
the fence.
(a) Need for Silt Fence
The need for a silt fence can be anticipated where construction activities
disturb and expose soil that could erode. The ground surface is considered
disturbed if vegetative cover is at least partially removed over a significant
area by construction activities. Consider whether or not silt-laden runoff
water from the disturbed area can reach an environmentally sensitive area or a
constructed stormwater system. If the exposed soil is a clean sand or gravel or
if a significant zone of heavy vegetative cover separates the exposed soil from
the environmentally sensitive area, a silt fence may not even be needed. Contact
the Headquarters (HQ) Hydraulics Section for help in determining whether or not
a silt fence is needed in such situations.
(b) Feasibility of Silt Fence
The feasibility of a geotextile silt fence depends on the magnitude of water flow
to the fence, the steepness of the slope behind the fence ,and whether or not flow
is concentrated at the fence. If the silt fence is not feasible, alternative erosion
control methods may be needed (see the Highway Runoff Manual).
Consider all feasible erosion control options in terms of potential effectiveness
and economy before making the final decision to use a silt fence. Select the best
option for the site conditions, including site geometry and contours, soil type, and
rainfall potential. Consider silt fences for temporary erosion control in disturbed
areas in the following circumstances:
• Fully covering disturbed areas temporarily with polyethylene sheeting or
other temporary covering is not feasible or practical.

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Geosynthetics Chapter 630

• Permanent ground cover for disturbed areas is not yet established.

• Runoff water reaches the silt fence primarily as sheet flow rather than as
concentrated flows, with the exception of some ditch and swale applications.
• Slopes above the silt fence are not steeper than 1.5H:1V.
• The sheet flow length (length of slope contributing runoff water to the silt
fence) is not too long.
(c) Sheet Flow Length
Maximum sheet flow lengths allowed for silt fences are provided in Exhibit
630-2, which is based on the typical 2-year, 24-hour design storm for
Washington, resulting in a 24-hour rainfall of 3 inches.
Slope Sheet Flow Length
1.5H:1V 100 ft
2H:1V 115 ft
4H:1V 150 ft
6H:1V 200 ft

Maximum Sheet Flow Lengths for Silt Fences

Exhibit 630-2

The sheet flow length represents the area contributing runoff water from
precipitation. The sheet flow length is defined in Exhibit 630-8. The sheet
flow lengths provided in Exhibit 630-2 were determined assuming a bare soil
condition, with the soil classified as a silt. These are worst-case assumptions
because less runoff would be expected for sand or gravel soils or when some
vegetation is present.
The sheet flow length is usually equal to or greater than the disturbed soil slope
length. However, undisturbed sloping ground above the disturbed slope area may
also contribute runoff to the silt fence area. The length of undisturbed sloping
ground above the disturbed slope to be included in the total contributing slope
length depends on the amount and type of vegetation present, the slope steepness,
and the degree of development above the slope.
If unsure whether the proposed silt fence meets the requirements in
Exhibit 630-2, contact the HQ Hydraulics Section for assistance.
Allowable Contributing Area
Average or Ditch Ditch or Swale
per Foot of Ditch or Swale
Swale Grade Storage Length
Storage Width
16% 13 ft 200 ft2
10% 20 ft 250 ft2
5% 40 ft 300 ft2
4% 50 ft 400 ft2
3% 65 ft 500 ft2
2% 100 ft 600 ft2
1% 200 ft 1000 ft2

Maximum Contributing Area for Ditch and Swale Applications

Exhibit 630-3

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Chapter 630 Geosynthetics

(d) Temporary Silt Fence

Temporary silt fences may also be used in ditch or swale applications. If the
area contributing runoff to the fence exceeds the value determined from Exhibit
630-3, hydraulic overload will occur. The ditch or swale storage length and width
are defined in Exhibit 630-9. The assumptions used in the development of Exhibit
630-3 are the same as those used for Exhibit 630-2 in terms of the design storm
and ground conditions.
As an example, if a site has a 13-foot-wide ditch with an average slope of 2%,
the fence can be located such that 7800 ft2 of area drain to it. If it appears that
the area draining to the fence will be larger than the allowable, it may be possible
to divide the contributing area into smaller areas and add a silt fence for each
smaller area as shown in Exhibit 630-10.
The minimum storage length for the ditch behind each silt fence must be
maintained. If this is not possible, it may be necessary to use an alternate erosion
control structure, as described in the Highway Runoff Manual, or develop a
special silt fence design.
Exhibit 630-3 was developed with the assumption that water will be able to pond
to a depth of at least 2 feet behind the fence. If this is not the case (the ditch or
swale depth is less than 2 feet), the table cannot be used. Furthermore, the ditch
depth must be greater than the height of the silt fence at its lowest point within
the ditch. Otherwise, there will not be enough storage available behind the fence
and water will circumvent the fence by flowing around it.
(e) Locating a Silt Fence
Locate silt fences on contour as much as possible. At the ends of the fence, turn
it up hill such that it captures the runoff water and prevents water from flowing
around the end of the fence. This is illustrated in Exhibit 630-11.
Silt fences are designed to capture up to a 2-foot depth of water behind the fence.
Therefore, the ground line at the ends of the fence must be at least 2 feet above
the ground line at the lowest part of the fence. This 2-foot requirement applies
to ditches as well as to general slope erosion control.
If the fence must cross contours (except for the ends of the fence), use gravel
check dams placed perpendicular to the back of the fence to minimize
concentrated flow and erosion along the back of the fence (see Exhibit 630-12).
• The gravel check dams are approximately 1 foot high at the back of the
fence and are continued perpendicular to the fence at the same elevation
until the top of the dam intercepts the ground surface behind the fence.
• Locate the gravel check dams every 10 feet along the fence.
• In general, the slope of the fence line is not to be steeper than 3H:1V.
• For the gravel check dams, use Crushed Surfacing Base Course, Gravel
Backfill for Walls, or Permeable Ballast (see the Standard Specifications).
If the silt fence application is considered critical (such as when the fence is
placed immediately adjacent to environmentally sensitive areas like streams,
lakes, or wetlands), place a second silt fence below the first silt fence to capture
any silt that passes through the first fence and/or place straw bales behind the silt
fence. Locate silt fences at least 7 feet from an environmentally sensitive area.

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December 2009
Geosynthetics Chapter 630

Where this is impossible, and a silt fence must be used, a special design may
be necessary.
Temporary silt fences are sometimes used to completely encircle underground
drainage inlets or other similar features to prevent silt from entering the drainage
system. This is acceptable, but the silt fence functions primarily as a barrier, and
not as a ponding or filtering mechanism, unless the drainage inlet is in a
depression that is large enough to allow water to pond behind the silt fence.
• If the drainage inlet and silt fence are not in a large enough depression, silt-
laden water will simply be directed around the fence and must be captured
by another fence or sedimentation pond downslope.
• If the depression is deep, locate the silt fence no more than 2 feet below the
top of the depression to prevent overtopping. A site-specific design may be
needed if the silt fence is located deeper than 2 feet within the depression.
It may be necessary to relocate silt fences during the course of a construction
project as cuts and fills are built or as disturbed areas change. An erosion
control/silt fence plan that accounts for the anticipated construction stages
(and eventual removal) should be developed. Do not assume that one silt fence
location can routinely be used for the entire life of the contract. Periodically
check the locations in the field during the construction project, and field-adjust
the silt fence locations as necessary to ensure the silt fences function as intended.

(7) Standard Specification Geotextile Application Identification in the

Contract Plans
Identify the geotextile in the contract plan detail in a way that ties it to the
appropriate application in the Standard Specifications. For example:
• If a geotextile is to be used to line an underground trench drain 3 feet deep and
the native soil has less than 15% passing the #200 sieve, identify the geotextile
on the plan sheet as “Construction Geotextile for Underground Drainage, Low
Survivability, Class A.”
• If the geotextile is to be placed beneath riprap on a slope without a cushion layer
between the geotextile and the riprap, and the native soil contains 35% passing
the #200 sieve, identify the geotextile on the plan sheet as “Construction
Geotextile for Permanent Erosion Control, High Survivability, Class B.”
• If the geotextile is to be placed between the roadway base course and a moist silt
subgrade with a resilient modulus of 6,500 psi, and the roadway is planned to be
constructed during the dry summer and early fall months, identify the geotextile
on the plan sheet as “Construction Geotextile for Separation.”

(8) Site-Specific Designs (All Applications)

A site-specific design is required:
• For all reinforcement applications.
• For applications not covered by the Standard Specifications.
Consider a site-specific design for:
• High-risk applications.
• Exceptionally large geotextile projects: if the geotextile quantity in a single
application is over 35,000 yd2 or over 85,000 yd2 for the separation application.
• Severe or unusual soil or groundwater conditions.

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Chapter 630 Geosynthetics

• Soil in the vicinity of the proposed geotextile location that consists of alternate
thin layers of silt or clay with potentially water-bearing sand layers on the order
of 1 to 3 inches thick or less.
• Soil known through past experience to be problematic for geosynthetic drains.
• Drains in native soil behind structures except drains contained within granular
backfill.
• Drains designed to stabilize unstable slopes.
• Drains designed to mitigate frost heave.
In such cases, obtain assistance from the HQ Materials Laboratory, Geotechnical
Services DivisionOffice. To initiate the special design, provide a plan and cross
section showing:
• The geosynthetic structure to be designed.
• The structure’s relative location to other adjacent structures that it could
potentially affect.
• The structure’s intended purpose.
• Any soil data in the vicinity.
Consider a site-specific design for temporary silt fences:
• If silt fence must be used in intermittent streams or where a significant portion
of the silt fence functions as a barrier that directs flow to the lower portions of
the silt fence.
• If the fence must be located on steep slopes.
• In situations not meeting the requirements in Exhibits 630-2 and 630-3.
• If the 2-year, 24-hour design storm for the site is greater than the 3 inches
assumed for the development of Exhibits 630-2 and 630-3.
• Where concentrated flow is anticipated.
• If closer than 7 feet from an environmentally sensitive area.
• If more than 2 feet of storage depth is needed.
For a site-specific temporary silt fence design, obtain assistance from the HQ
Hydraulics Section. To initiate the design, send the following information to
the HQ Hydraulics Section and a copy to the HQ Materials Laboratory,
Geotechnical Services DivisionOffice:
• Plan sheets showing proposed silt fence locations and grading contours.
• Estimate of the area contributing runoff to each silt fence, including percentage
and general type of vegetative cover within the contributing area.
• Any available site soil information.
For all site-specific designs of applications not covered by the Standard
Specifications, complete plans and special provisions are needed. In general, for site-
specific designs of Standard Specifications applications, only a minor modification
of the appropriate geotextile property table will be needed.

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July 2013
Geosynthetics Chapter 630

630.06 Design Responsibility

The design responsibility and process for geotextile design are illustrated in Exhibits
630-4 and 630-5. The region Project Development Office, in particular the region
Project Manager, is responsible to initiate and develop all geotextile designs for
the Standard Specifications, except for roadway separation and soil stabilization
applications, which are initiated and developed by the region Materials Laboratory.
The region Materials Laboratory assists the region Project Manager with Standard
Specifications underground drainage and permanent erosion control designs.
The region Environmental Design Office assists with Standard Specifications,
permanent erosion control, and temporary silt fence designs.
Once the region Project Manager or Materials Laboratory has determined that
a geotextile is appropriate, development of a geotextile design for the Standard
Specifications includes the development of plan details showing the plan location
and cross section of the geotextile installation. Standard details for geotextiles as
provided in the Plans Preparation Manual may be used or modified to adapt to
the specific project situation. Note that only minimum dimensions for drains are
provided in these standard details.
Site-specific geosynthetic designs and applications not addressed by the Standard
Specifications are designed by the region with the assistance of the HQ Materials
Laboratory, Geotechnical Services DivisionOffice, or the HQ Hydraulics Section as
described in 630.05.
Design assistance by the HQ Geotechnical Services DivisionOffice or HQ Hydraulics
Section for site-specific design of Standard Specifications applications includes
determination of geosynthetic properties and other advice as needed to complete
the geosynthetic plans and any special provisions required.
The HQ Geotechnical Services DivisionOffice is fully responsible to develop and
complete the following:
 Geosynthetic design, plan details that can be used to develop the contract
plan sheets, and special provisions for geosynthetic reinforced walls, slopes,
and embankments.
 Deep trench drains for landslide stabilization.
 Other applications that are an integral part of a Headquarters geotechnical design.

The region Project Manager incorporates the plan details and special provisions into
the PS&E.

630.07 Documentation
For the list of documents required to be preserved in the Design Documentation Package and
the Project File, see the Design Documentation Checklist:
 www.wsdot.wa.gov/design/projectdev/ Refer to Chapter 300 for design documentation
requirements.

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Chapter 630 Geosynthetics

Design Process for Drainage and Erosion Control:

Geotextiles and Nonstandard Applications
Exhibit 630-4

WSDOT Design Manual M 22-01.05 Page 630-15

July 2013
Geosynthetics Chapter 630

Region Project Manager (RPM) defines application

Separation/soil Temporary silt fence

stabilization (sediment control)

RML assesses site conditions, RPM assesses need for geotextile

obtains soil samples as needed, silt fence (see the Highway Runoff
assesses need for geotextile, and Manual for additional information) –
determines whether the Standard This is generally addressed as part
Specifications applies of the permitting process

Geotextile needed Not needed Silt fence needed Not needed

Is site-specific RPM assesses Apply other

design required? whether Standard erosion control
End Specification designs measures as
apply required

Yes No, use Standard Specs.

No, do site- Yes, use End

HQGSD RML arranges for any
testing needed and uses specific Standard
assists with
resilient modulus, design Specs.
geotextile
property considering site
selection conditions, to select
geotextile properties
RPM submits site data to
HQ Hydraulics Section –
HQ Hydraulics Section RPM
completes silt fence completes
design and submits standard silt
design to RPM fence design
RML includes
geotextile design
requirements in
geotechnical or
resurfacing report

RPM selects/modifies
RPM = Region Project Manager appropriate details from the
RML = Region Materials Laboratory Standard Plans and
HQGSD = HQ Geotechnical Services Division completes silt fence plans

Design Process for Separation, Soil Stabilization, and Silt Fence

Exhibit 630-5

Page 630-16 WSDOT Design Manual M 22-01.05

June 2009
Chapter 630 Geosynthetics

Slit Film Woven Geotextile

Monofilament Woven Geotextile

Multifilament Woven Geotextile

Examples of Various Geosynthetics

Exhibit 630-6

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June 2009
Geosynthetics Chapter 630

Needle-Punched Nonwoven Geotextile Heat-Bonded Nonwoven Geotextile

Geocomposite Drains (Geotextile With Core)

Extruded and Woven Geogrids

Examples of Various Geosynthetics

Exhibit 630-6 (continued)

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June 2009
Chapter 630 Geosynthetics

Surfacing
Gravel Buttress

Base Course

Subgrade < 6 ft

Geotextile
Geotextile

A. Underground Drainage: B. Underground Drainage:

Low Survivability Moderate Survivability
(Roadway Trench Drain) (Area Drain Beneath Buttress)

Surfacing

> 6 ft

Geotextile Drainable Base Course

Gabion Wall Geotextile

C. Underground Drainage: D. Underground Drainage:

Moderate Survivability Moderate Survivability
(Geotextile Sheet Drain) (Area Drain Under Parking Lot or Roadway)

Wall Backfill

Geotextile > 6 ft

Geotextile

E. Underground Drainage: F. Underground Drainage:

Low Survivability Moderate Survivability
(Wrapped Drain Behind Foundation) (Deep Trench Drain for Slope Stabilization)

Geotextile Application Examples

Exhibit 630-7

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June 2009
Geosynthetics Chapter 630

Surfacing

Base Course
Subgrade
Geotextile

G. Separation or Soil Stabilization for New Roadway

(Depends on Subgrade Condition)

Surfacing

New Pavement
Base Course

Subgrade Geotextile
Existing Pavement

H. Separation or Soil Stabilization for Widened Roadway

(Depends on Subgrade Condition)

Riprap

Aggregate Cushion

Geotextile

I. Permanent Erosion Control:

Moderate Survivability

Riprap

Geotextile

J. Permanent Erosion Control:

High Survivability

Geotextile Application Examples

Exhibit 630-7 (continued)

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June 2009
Chapter 630 Geosynthetics

< 16 ft

Quarry Spalls
1
2 min.
Geotextile

K. Ditch Lining

Fence
Geotextile

Runoff

L. Silt Fence Not Immediately Adjacent to Environmentally Sensitive Area

Geotextile
Fence
Geotextile off
Run
Fence

M. Silt Fence Immediately Adjacent to Environmentally Sensitive Area

Geotextile Application Examples

Exhibit 630-7 (continued)

WSDOT Design Manual M 22-01.05 Page 630-21

June 2009
Geosynthetics Chapter 630

Wall Top
Surfacing
Base Course

Subgrade
Soil Nail
Sand Backfill
Wall Base
Prefabricated Geotextile
Wrapped Drain Prefabricated Geotextile
Wrapped Drain Strip

N. Prefabricated Edge Drain for Roadway O. Prefabricated Drain Strip Behind

Wall Face

Geosynthetic
Geosynthetic
Layers Layers

P. Geosynthetic Wall Q. Geosynthetic Reinforced Slope

Fill
Base Course

Very Soft Subsoil Geosynthetic Layers Very Soft

Subgrade Geosynthetic

S. Geosynthetic Subgrade Reinforcement for Temporary

R. Geosynthetic Reinforced Embankment
Roads

Geotextile Application Examples

Exhibit 630-7 (continued)

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June 2009
Chapter 630 Geosynthetics

gth*
lo p e Len
nal S
A dditio

)
(L
h
n gt
Le
o pe e
Sl n of
Sl o p
rti o d
Po isturb
e
Not D
to
u e es
ti
o il D tivi
S Ac
b e d io n
r ct
i stu stru
D n
Co

* May need to be included as part of slope length

depending on vegetative cover, slope steepness,
and degree of development above slope

Definition of Slope Length

Exhibit 630-8

WSDOT Design Manual M 22-01.05 Page 630-23

June 2009
Geosynthetics Chapter 630

Ditch or Swale Storage Length (LS)

Lowest Point
at top of
d
Geotextile

Bottom of Ditch or Swale

Silt Fence

Storage Length

Ditch or Swale Storage Width (WS)

d
Cross Section
of Ditch or Swale
Bottom of Ditch or Swale

Storage Width

Definition of Ditch or Swale Storage Length and Width

Exhibit 630-9

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June 2009
Chapter 630 Geosynthetics

Top of Slope

Area 1 Area 2 Area 3

Silt Fence 1 Silt Fence 2 Silt Fence 3

Bottom of Ditch or Swale Downhill

Slope

LS1 (Min) LS2 (Min) LS3 (Min)

Area 1 Area 2 Area 3

Top of Slope

Method to keep contributing area to ditch or swale within allowable limits if

contributing area is too large based on Exhibit 630-3.

Silt Fences for Large Contributing Area

Exhibit 630-10

WSDOT Design Manual M 22-01.05 Page 630-25

June 2009
Geosynthetics Chapter 630

Bottom of Slope

Silt Fence

Sheet Flow

Top of Slope

Silt Fence Plan

2 ft. min

Silt Fence Profile

Silt fence plan and profile illustrating how silt fence will capture
runoff water and not allow water to run around ends of fence.

Silt fence plan and profile illustrating how

silt fence will capture runoff water and
not allow water to run around ends of fence.

Silt Fence End Treatment

Exhibit 630-11

Page 630-26 WSDOT Design Manual M 22-01.05

June 2009
Chapter 630 Geosynthetics

Silt Fence

1
3 min
Gravel
Check Dam 1 ft

Ground Line A

max.
10 ft

Profile

Geotextile

Gravel Check Dam

Ground Line
1 ft

Cross Section A-A

Gravel Check Dams for Silt Fences

Exhibit 630-12

WSDOT Design Manual M 22-01.05 Page 630-27

June 2009
 Project Development
Roles and Responsibilities
Chapter 700 for Projects With Structures
700.01 General
700.02 Procedures

700.01 General
This chapter presents the project development process used by the Washington State
Department of Transportation (WSDOT) in the regions and the Headquarters (HQ)
Bridge and Structures Office to determine the roles and responsibilities for projects
with structures during the project development phase of a project. This chapter
complements WSDOT’s Project Management Online Guide:
 http://www.wsdot.wa.gov/projects/projectmgmt/pmog.htm
For design procedures, see Division 7 chapters and the Bridge Design Manual.
The primary objective of this process is to provide a consistent means of selecting
a bridge design team to perform the structural design work, whether it is by a
consultant or the HQ Bridge and Structures Office.
If the local agency will be requesting any services from WSDOT, the local agency
will contact WSDOT’s Local Programs Engineer, who will help define the level
of WSDOT’s involvement in design and construction.

700.02 Procedures
The flow diagram (see Exhibit 700-1) begins at the left with the initial approval
and funding of the project and ends at the right with the start of the project
delivery process.
After a project is programmed, WSDOT is tasked with confirming the project scope
and defining the structural team’s level of involvement in design and construction.
If a consultant is not used, the bridge design work will be performed by the HQ
Bridge and Structures Office. If a consultant is used, the region and the HQ Bridge
and Structures Office will determine the level of involvement and responsibility
for the design.
Agreements defining the level of involvement and responsibility will be developed
and executed between the region office responsible for project development and the
HQ Bridge and Structures Office, and the appropriate project delivery process will
be implemented.
More information on this process and the desired outcomes is available on the
HQ Bridge and Structures Office’s home page:
 http://www.wsdot.wa.gov/bridge/structures

WSDOT Design Manual M 22-01.11 Page 700-1

July 2014
Project Development Roles and Responsibilities for Projects With Structures Chapter 700

Considerations:
· On/off state system
· In/out state ROW
· Funding source

Approved & initially

funded projects

No
Potential B&SO level
of involvement:
· Administrator
Confirm Project Delivery · Designer
Process: · Technical review
Obtain structural & other · CN contract (DB, DBB) · Advise
technical assistance & · Phasing · Specific tasks
guidance for project · Schedule · Portions of projects
scoping · Environmental · None

Obtain written letter or

Identify owner, design agreement on B&SO level
lead, & key players: of involvement
Confirm Project Definition
– Prospectus (Negotiation · WSDOT region (responsibility & Consultant to
Yes
Flowchart: Step 1) · Local agency availability) be used?
· Tribal for design & construction
· Private entity (Project Management
Online Guide)

FHWA: Federal Highway Administration

WSDOT: Washington Sate Department of Transportation
DB: Design-Build
DBB: Design-Bid-Build
Provide consultants
B&SO: WSDOT Bridge & Structures Office
an unofficial list
ROW: Right of Way
(prepared by B&SO)
CN: Construction
of programmed projects
on WSDOT website

Determination of the Roles and Responsibilities for Projects With Structures:

Project Development Phase
Exhibit 700-1

Page 700-2 WSDOT Design Manual M 22-01.05

June 2009
Chapter 700 Project Development Roles and Responsibilities for Projects With Structures

Work programmed for B&SO

Considerations:
· Total project done by
consultant: Region
administrators, B&SO
technical review and
consultant selection
· Bridge work by
consultant, other work
by region: B&SO
administrators, technical
review and consultant
selections
· Some bridge work by Proceed with Project
consultant Management Online Guide
· Consultant responsibilities
during construction

No

Determine consultant level Is written letter or

of project responsibilities agreement on B&SO Consultant to
Yes
(Project Management level of involvement be used?
Online Guide) valid?

Yes

Preliminary list of projects

programmed for the Consultant selection
use of consultants (Negotiation Flowchart:
on WSDOT website Step 2)
(prepared by B&SO)

No

Revisit & revise

written Letter or
Agreement Continue with WSDOT’s
Negotiation Flowchart &
Proceed with Project
Management Online Guide

Determination of the Roles and Responsibilities for Projects With Structures:

Project Development Phase
Exhibit 700-1 (continued)

WSDOT Design Manual M 22-01.05 Page 700-3

June 2009
Project Development Roles and Responsibilities for Projects With Structures Chapter 700

Page 700-4 WSDOT Design Manual M 22-01.05

June 2009
Chapter 710 Site Data for Structures
710.01 General
710.02 Required Data for All Structures
710.03 Additional Data for Waterway Crossings (Bridges and Buried Structures)
710.04 Additional Data for Grade Separations
710.05 Additional Data for Widenings
710.06 Site Data for Design-Build Conceptual Drawings
710.07 Documentation
710.08 References

710.01 General
The Washington State Department of Transportation (WSDOT) Headquarters (HQ) Bridge and
Structures Office provides preliminary site data reviews to determine the applicability of, and
requirements surrounding, proprietary structural solutions, or the need for specific structural
design strategies, as well as structural design services to the regions. This chapter describes the
information required by the HQ Bridge and Structures Office to perform these functions.

710.02 Required Data for All Structures

Structure site data provides information about the type of crossing, topography, type of
structure, and potential future construction. Submit structure site data to the HQ Bridge and
Structures Office for all structures meeting the Chapter 720 definition of a bridge: essentially all
structures with an interior span equal to 20 feet or greater measured along the overcrossing
alignment. This includes all buried structures such as precast concrete arch structures,
reinforced concrete arch structures, precast reinforced concrete three-sided structures, precast
reinforced concrete box culverts, and precast reinforced concrete split box culverts. Site data
shall also provide information on nonstandard retaining walls needing project-specific design by
the HQ Bridge and Structures Office.

Submit the structure site data to the HQ Bridge and Structures Office, Project Support unit, by
email. In the email message, provide a general description of the project and provide a bullet
list itemization of the structure site data forms, files, and data attached or linked in the email.
Submit the structure site data as a CAD file with associated supplemental drawings and a report.
(See Exhibit 710-1 for items to include in a structure site data submittal). Direct any questions
relating to the preparation of structure site data to the HQ Bridge and Structures Office, Project
Support unit. The Bridge Design Manual shows examples of required WSDOT forms.

710.02(1) Scour
At any location where a structure can be in contact with water (such as culvert outfall, lake,
river, or floodplain), there is a risk of scour. This risk is to be analyzed as part of the Hydraulic
Report. Contact the HQ Geotechnical Office and the HQ Hydraulics Office to determine whether
a scour analysis is required.

WSDOT Design Manual M 22-01.17 Page 710-1

September 2019
Site Data for Structures Chapter 710

710.02(2) CAD Files and Supplemental Drawings

CAD files prepared for use as structure site data shall be submitted in DGN (preferred) or DWG
(acceptable) format.

Prepare plan, profile, and section drawings for all structures. Include copies of the CAD site data
and supplemental drawings in the 11 x 17 plan sheet format with the submittal.

Use a complete and separate CAD file for each structure. Create the base map in 2D expanded
level format only at 1:1 scale, with only one model per DGN or DWG file, and all base map levels
in accordance with the Electronic Engineering Data Standards manual. Create a separate base
map in 3D with the alignment and contour lines only—no contour text. Turn on all levels
(existing and proposed) and merge all reference files, leaving the reference file list empty. Put
the new and existing alignments in the same file.

The Bridge Design Manual contains examples of completed bridge preliminary plans. These
plans show examples of the line styles and drawing format for site data in CAD.

Structure site data is used to prepare the layout plan, which is to be used in the contract plans.
Include the following information in the CAD files or in the supplemental drawings.
710.02(2)(a) Plan
 Vertical and horizontal datum control (see Chapters 400 and 410).
 Contours of the existing ground surface (index and intermediate). Use intervals of 2
feet. Show contours beneath an existing or proposed structure and beneath the water
surface of any waterway. Do not partially delete contour lines that cover index contour
text.
 Alignment of the proposed highway and multimodal traffic channelization in the
vicinity.
 Location by section, township, and range.
 Type, size, and location of all existing or proposed sewers, telephone and power lines,
water lines, gas lines, traffic barriers, culverts, bridges, buildings, and walls.
 Location of right of way lines and easement lines.
 Distance and direction to nearest state highway intersections along the main alignment
in each direction.
 Location of all roads, streets, and detours.
 Stage construction plan and alignment.
 Type, size, and location of all existing and proposed sign structures, light standards, and
associated conduits and junction boxes. Provide proposed signing and lighting items
when the information becomes available.
 Location of existing and proposed drainage.
 Horizontal curve data. Provide the Inroads report for each alignment. Include
coordinates for all control points.

Page 710-2 WSDOT Design Manual M 22-01.17

September 2019
Chapter 710 Site Date for Structures

710.02(2)(b) Profile
 Profile view showing the grade line of the proposed or existing alignment and the
existing ground line along the alignment line.
 Vertical curve data. Provide the Inroads report for each alignment along with the CAD
detail.
 Superelevation transition diagram for each alignment as applicable.

710.02(2)(c) Section
 Channelization roadway sections on the structure and at structure approaches.
Indicate the lane and shoulder widths, cross slopes and side slopes, ditch dimensions,
and traffic barrier requirements.
 Stage construction roadway geometrics with the minimum lane and roadway widths
specified.

710.02(3) Report
Submit DOT Form 235-002, Bridge Site Data-General. Supplement the CAD drawings with the
following items:
 Vicinity maps
 Class of highway
 Design speed
 Special requirements for replacing or relocating utility facilities
 ADT and DHV counts
 Truck traffic percentage
 Requirements for road or street maintenance during construction

710.02(4) Video and Photographs

Submit a video of the site. Show all the general features of the site and details of existing
structures. Scan the area slowly, spending extra time showing existing bridge pier details and
end slopes. A “voice over” narrative on the video is necessary for orientation.

Color photographs of the structure site are desirable. Include detailed photographs of existing
abutments, piers, end slopes, and other pertinent details for widenings, bridge replacements, or
sites with existing structures.

710.03 Additional Data for Waterway Crossings (Bridges and Buried

Structures)
Coordinate with the HQ Hydraulics Section and supplement the structure site data for all
waterway crossings with the DOT Form 235-001, Bridge Site Data for Stream Crossings, and the
following:
 Show riprap or other slope protection requirements at the structure site (type, plan
limits, and cross section) as determined by the HQ Hydraulics Section.

WSDOT Design Manual M 22-01.17 Page 710-3

September 2019
Site Data for Structures Chapter 710

 Show a profile of the waterway. The extent will be determined by the HQ Hydraulics
Section.
 Show cross sections of the waterway including new streambed design, defining the
bankfull width and the bank shelf widths and slopes. The extent will be determined by
the HQ Hydraulics Section. The requirements for waterway profile and cross sections
may be less stringent if the HQ Hydraulics Section has sufficient documentation (FEMA
reports, for example) to make a determination. Contact the HQ Hydraulics Section to
verify the extent of the information needed. Coordinate any rechannelization of the
waterway with the HQ Hydraulics Section.
 Many waterway crossings require a permit from the U.S. Coast Guard (see Bridge
Design Manual Chapter 2.2.4 and the Environmental Manual). Generally, ocean tide-
influenced waterways and waterways used for commercial navigation require a Coast
Guard permit. These structures require the following additional information:
Names and addresses of the landowners adjacent to the bridge site.
Quantity of new embankment material within the floodway. This quantity
denotes, in cubic yards, the material below and the material above normal
high water.

For all waterway crossings, where the structure parallel to the centerline of roadway width is
less than 20 feet, the Region’s designer shall contact the US Coast Guard for determination of
waterway jurisdiction and any associated permit requirements. For all waterway crossings,
where the structure parallel to the centerline of roadway width is 20 feet or greater, the Bridge
and Structures Office US Coast Guard Liaison will contact the US Coast Guard for determination
of waterway jurisdiction and any associated permit requirements.

The Region is responsible for coordination with the HQ Bridge and Structures Office, U.S. Army
Corps of Engineers, and U.S. Coast Guard for waterways that may qualify for an exemption to
navigation permit requirements. The HQ Bridge and Structures Office is responsible for
coordination with the U.S. Coast Guard for waterways that require a navigation permit.

710.04 Additional Data for Grade Separations

710.04(1) Highway-Railroad Separation

Supplement structure site data for structures involving railroads with the following:

710.04(1)(a) Plan
 Alignment of all existing and proposed railroad tracks.
 Center-to-center spacing of all tracks.
 Angle, station, and coordinates of all intersections between the highway alignment and
each track.
 Location of railroad right of way lines.
 Horizontal curve data. Include coordinates for all curve control points.

Page 710-4 WSDOT Design Manual M 22-01.17

September 2019
Chapter 710 Site Date for Structures

710.04(1)(b) Profile
 For proposed railroad tracks: profile, vertical curve, and superelevation data for each
track.
 For existing railroad tracks: elevations accurate to 0.1 foot taken at 10-foot intervals
along the top of the highest rail of each track. Provide elevations to 50 feet beyond the
extreme outside limits of the existing or proposed structure. Tabulate elevations in a
format acceptable to the HQ Bridge and Structures Office.

710.04(2) Highway-Highway Separation

Supplement structure site data for structures involving other highways by the following:

710.04(2)(a) Plan
 Alignment of all existing and proposed highways, streets, and roads.
 Angle, station, and coordinates of all intersections between all crossing alignments.
 Horizontal curve data. Include coordinates for all curve control points.
710.04(2)(b) Profile
 For proposed highways: profile, vertical curve, and superelevation data for each.
 For existing highways: elevations accurate to 0.1 foot taken at 10-foot intervals along
the centerline or crown line and each edge of shoulder, for each alignment, to define
the existing roadway cross slopes. Provide elevations to 50 feet beyond the extreme
outside limits of the existing or proposed structure. Tabulate elevations in a format
acceptable to the HQ Bridge and Structures Office.
710.04(2)(c) Section
 Roadway sections of each undercrossing roadway indicating the lane and shoulder
widths, cross slopes and side slopes, ditch dimensions, and traffic barrier requirements.
 Falsework or construction opening requirements. Specify minimum vertical clearances,
lane widths, and lateral clearances.

710.05 Additional Data for Widenings

Bridge rehabilitations and modifications that require new substructure are defined as bridge
widenings.

710.05(1) Bridge Widenings

Submit DOT Form 235-002A, Supplemental Bridge Site Data-Rehabilitation/ Modification.
Supplement structure site data for structures involving bridge widenings by the following:
710.05(1)(a) Plan
 Stations for existing back of pavement seats, expansion joints, and pier centerlines
based on field measurements along the survey line and each curb line.
 Locations of existing bridge drains. Indicate whether these drains are to remain in use
or be plugged.

WSDOT Design Manual M 22-01.17 Page 710-5

September 2019
Site Data for Structures Chapter 710

 Description of existing barriers, railings, expansion joints, and bridge attachments, in

accordance with Form 235-002A.

710.05(1)(b) Profile
 Elevations accurate to 0.1 foot taken at 10-foot intervals along the curb line of the side
of the structure being widened. Pair these elevations with corresponding elevations
(same station) taken along the crown line or an offset distance (10-foot minimum from
the curb line). This information will be used to establish the cross slope of the existing
bridge. Tabulate elevations in a format acceptable to the HQ Bridge and Structures
Office.

Take these elevations at the level of the concrete roadway deck. For bridges with concrete
overlay, elevations at the top of the overlay will be sufficient. For bridges with a
nonstructural overlay, such as an asphalt concrete overlay, take elevations at the level of
the concrete roadway deck. For skewed bridges, take elevations along the crown line or at
an offset distance (10-foot minimum from the curb line) on the approach roadway for a
sufficient distance to enable a cross slope to be established for the skewed corners of the
bridge.

710.06 Site Data for Design-Build Conceptual Drawings

Structure site data content and submittal requirements for development of structure conceptual
drawings associated with Design-Build projects are similar but simplified to those associated
with Design-Bid-Build projects. The simplified content requirements are outlined in Exhibit 710-
2. The submittal of elements identified in Exhibit 710-2 as conceptual plan structure site data
components shall conform to and be as described in Sections 710.02 through 710.05

710.07 Documentation
Refer to Chapter 300 for design documentation requirements.

710.08 References
Bridge Design Manual, M 23-50, WSDOT

Electronic Engineering Data Standards, M 3028

Environmental Manual, M31-11

Hydraulics Manual, M 23-03

Page 710-6 WSDOT Design Manual M 22-01.17

September 2019
Chapter 710 Site Date for Structures

Exhibit 710-1 Structure Site Data Checklist

_____ InRoads reports
PLAN (in CAD file)
_____ Survey Lines and Station Ticks FORMS (information noted on the form or attached
_____ Survey Line Intersection Angles on supplemental sheets or drawings)
_____ Survey Line Intersection Stations Bridge Site Data General
_____ Survey Line Bearings _____ Slope Protection
_____ Roadway and Median Widths _____ Pedestrian Barrier/Pedestrian Rail Height
_____ Lane and Shoulder Widths Requirements
_____ Sidewalk Width _____ Construction/Falsework Openings
_____ Bicycle and Pedestrian Facility and widths _____ Stage Construction Channelization Plans
_____ Connection/Widening for Traffic Barrier _____ Bridge (before/with/after) Approach Fills
_____ Profile Grade and Pivot Point _____ Datum
_____ Roadway Superelevation Rate (if constant) _____ Video of Site
_____ Lane Taper and Channelization Data _____ Photographs of Site
_____ Traffic Arrows _____ Control Section
_____ Mileage to Towns Along Main Line _____ Project Number
_____ Existing Drainage Structures _____ Region Number
_____ Existing Utilities: Type/Size/Location _____ Highway Section
_____ New Utilities: Type/Size/Location
_____ Light Standards, Junction Boxes, Conduits Bridge Site Data for Stream Crossings
_____ Bridge-Mounted Signs and Supports _____ Water Surface Elevations and Flow Data
_____ Contours _____ Riprap Cross Section Detail
_____ Bottom of Ditches _____ Bankfull width
_____ Test Holes (if available) _____ Bank shelf width
_____ Riprap Limits
_____ Stream Flow Arrow Supplemental Bridge Site Data: Rehabilitation/
Modification
_____ R/W Lines and/or Easement Lines
_____ Exist. Bridge No. (to be removed, widened)
BRIDGE, CROSSROAD, AND APPROACH ROADWAY
_____ Section, Township, Range
CROSS SECTIONS (may be in CAD file or on separate
_____ City or Town
drawings)
_____ North Arrow
_____ Bridge Roadway Width
_____ SR Number
_____ Lane and Shoulder Widths
_____ Scale
_____ Profile Grade and Pivot Point
TABLES (in tabular format in CAD file) _____ Superelevation Rate
_____ Curb Line Elevations at Top of Existing _____ Survey Line
Bridge Deck _____ Pedestrian facility width
_____ Undercrossing Roadway Existing Elevations _____ Bicycle facility width
_____ Undercrossing Railroad Existing Elevations _____ PB/Pedestrian Rail Dimensions
_____ Curve Data _____ Stage Construction Lane Orientations
OTHER SITE DATA (may be in CAD file or on _____ Locations of Temporary Barrier
supplemental sheets or drawings) _____ Conduits/Utilities in Bridge
_____ Superelevation Diagrams _____ Location and Depth of Ditches
_____ End Slope Rate _____ Shoulder Widening for Barrier
_____ Profile Grade Vertical Curves _____ Side Slope Rate
_____ Coast Guard Permit Status
_____ Railroad Agreement Status
_____ Highway Classification
_____ Design Speed
_____ ADT, DHV, and % Trucks

WSDOT Design Manual M 22-01.17 Page 710-7

September 2019
Exhibit 710-2 Conceptual Plan Structure Site Data Checklist

PLAN (in CAD file) FORMS (information noted on the form or attached
Survey Lines and Station Ticks on supplemental sheets or drawings)
Survey Line Bearings Bridge Site Data General
Roadway and Median Widths Pedestrian Barrier/Pedestrian Rail Height
Lane and Shoulder Widths Datum
_____Bicycle and Pedestrian Facility and widths Control Section
Bridge Deck Sidewalk Width Project Number
Profile Grade and Pivot Point Region Name
Roadway Superelevation Rate (if constant) Project Name
Traffic Arrows Bridge Site Data for Stream Crossings
Existing utilities Type, Size, and Location Water Surface Elevations and Flow Data
Contours Bankfull Width
Stream Flow Arrow Bank shelf width
R/W Lines and/or Easement Lines BRIDGE, CROSSROAD, & APPROACH ROADWAY
Exist. Bridge No. (to be removed, widened) CROSS SECTIONS (may be in CAD file or on
Section, Township, Range Separate drawings)
County, City or Town Bridge Roadway Width
North Arrow Lane and Shoulder Widths
SR Number _____Bicycle facility width
Scale _____Pedestrian facility width
TABLES (in tabular format in CAD file) Profile Grade and Pivot Point
Curb Line Elevations at Top of Existing Br. Deck Superelevation Rate
Undercrossing Roadway Existing Elevations Survey Line
Undercrossing Railroad Existing Elevations PB/Pedestrian Rail Dimensions
Curve Data
OTHER SITE DATA (may be in CAD file or on
supplemental sheets or drawings)
Superelevation Diagrams
Profile Grade Vertical Curves
Railroad Agreement Status
Highway Classification
Design Speed
ADT, DHV, and % Trucks
In Roads reports

WSDOT Design Manual M 22-01.17 Page 710-8

September 2019
Chapter 720 Bridges
720.01 General
720.02 Bridge Locations
720.03 Bridge Site Design Elements
720.04 Coordination with US Coast Guard for Existing Bridges
720.05 Documentation
720.06 References

720.01 General
The National Bridge Inspection Standards (NBIS), published in the Code of Federal Regulations
(23 CFR 650, Subpart C), defines a bridge as:

A structure including supports erected over a depression or an obstruction, such as

water, highway, or railway, and having a track or passageway for carrying traffic or
other moving loads, and having an opening measured along the center of the roadway
of more than 20 feet between undercopings of abutments or spring lines of arches, or
extreme ends of openings for multiple boxes; it may also include multiple pipes, where
the clear distance between openings is less than half of the smaller contiguous
opening.

The term “bridge” as used in this chapter applies to all structures conforming to the above
definition. This includes all buried structures of a span greater than 20 feet measured along the
overcrossing alignment, such as precast reinforced concrete three-sided structures, precast
reinforced concrete box culverts, and precast reinforced concrete split box culverts.

Bridge design is the responsibility of the Washington State Department of Transportation

(WSDOT) Headquarters (HQ) Bridge and Structures Office, which develops a preliminary bridge
plan for a new or modified structure in collaboration with the region. This chapter provides basic
design considerations for the development of this plan. Unique staging requirements,
constructability issues, and other considerations are addressed during plan development.
Contact the HQ Bridge and Structures Office early in the planning stage regarding issues that
might affect the planned project (see Chapter 700).

720.02 Bridge Locations

Bridge locations are chosen to conform to the alignment of the highway. Conditions that can
simplify design efforts, minimize construction activities, and reduce structure costs are:
 A perpendicular crossing.
 The minimum required horizontal and vertical clearances.
 A constant bridge width (without tapered sections).
 A tangential approach alignment of sufficient length not to require superelevation on
the bridge.
 A crest vertical curve profile that will facilitate drainage.
 An adequate construction staging area.

WSDOT Design Manual M 22-01.17 Page 720-1

September 2019
Bridges Chapter 720

720.03 Bridge Site Design Elements

720.03(1) Structural Capacity

The structural capacity of a bridge is a measure of the structure’s ability to carry vehicle loads.
For new bridges, the bridge designer chooses the design load that determines the structural
capacity. For existing bridges, the structural capacity is calculated to determine the “load rating”
of the bridge. The load rating is used to determine whether or not a bridge is “posted” for legal
weight vehicles or “restricted” for overweight permit vehicles.

720.03(1)(a) New Structures

All new structures that carry vehicular loads are designed to HL-93 notional live load in
accordance with AASHTO’s LRFD Bridge Design Specifications.

720.03(1)(b) Existing Structures

When the structural capacity of a bridge will be affected by the project, the Region requests a
Structural Capacity Report from the Risk Reduction Engineer in the HQ Bridge and Structures
Office. Permanent redistribution of traffic, introduction of median barrier, and widening or deck
rehabilitation are among the triggers for evaluation of a bridge’s structural capacity. The report
will state:
 The structural capacity status of the structures within the project limits.
 What action, if any, is appropriate.

The Region requests the Bridge and Structures Asset Manager to provide status about whether a
bridge is included in the 6-year or 20-year plans for replacement or rehabilitation under the
P2 program and, if so, in which biennium the P2 project is likely to be funded.

The criteria used by the Bridge and Structures office to evaluate the structural capacity of a
bridge are as follows:
1. On National Highway System (NHS) routes (including Interstate routes):
• The operating load rating is at least 36 tons (which is equal to HS-20).
• The bridge is not permanently posted for legal weight vehicles.
• The bridge is not permanently restricted for vehicles requiring overweight
permits.
2. On non-NHS routes:
• The bridge is not permanently posted for legal weight vehicles.
• The bridge is not permanently restricted for vehicles requiring overweight
permits.

Include the Structural Capacity Report in the Project File (see Chapter 300).

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September 2019
Chapter 720 Bridges

720.03(2) Bridge Widths

The Design Manual contains multiple chapters that provide geometric cross section criteria and
procedures relevant to determining design element widths. See Chapter 1230 for a guide to
chapters that provide geometric cross section element widths.

While it is preferred not to alter the continuity of a roadway, there may be situations where
providing a structure width more or less than the roadway approaching the structure is
appropriate.

All structures on city or county routes crossing over a state highway must conform to the Local
Agency Guidelines.

For structures involving railroads, contact the HQ Design Office Railroad Liaison.

720.03(3) Horizontal Clearance

Horizontal clearance for structures is the distance from the edge of the traveled way to bridge
piers and abutments, traffic barrier ends, or bridge end embankment slopes. Minimum
distances for this clearance vary depending on the type of structure. (See Chapters 1239, 1600,
and 1610 and the Bridge Design Manual for guidance on horizontal clearance.)

For structures involving railroads, contact the HQ Design Office Railroad Liaison.

720.03(4) Bridge Medians

Designs for bridges on divided multilane highways often include the decision to join parallel
bridges as one or build them as independent structures. There are several factors in this
decision, such as in new corridor construction, phased construction of corridors, and the general
median width of the divided highway. This section covers some common design considerations
related to bridge medians.

Advances in crash barriers and their applications have resulted in an expanded set of choices for
bridge medians on divided highways.

Modern barrier designs and applications have allowed for longer runs of traffic barrier, different
barrier types, and bullnose guardrail designs for shielding the gap between parallel structures.
These tools have reduced collisions with abrupt bridge ends as well as shielded the opening
between bridges.

Some highway corridors are initially planned as multilane divided highways but may be
developed in logical, affordable phases and individual projects. This could result in an initial
phase where a corridor may open as a two-lane rural highway used by both travel directions. A
later phase could convert the facility to a divided highway, bringing with it the need for median
separation. Consider the long-range plans when determining median widths for bridges. The
photos in Exhibit 720-1 show a completed multilane highway where two separate bridges were
ultimately constructed years apart and a new corridor underway where one bridge is now built.

Joining two structures may not be the most cost-effective or sustainable solution for all projects.
Coordinate with the Bridge and Structures Office and the local Maintenance Office when
discussing options and concerns. For bridges on parallel horizontal and vertical alignments,
practical considerations for joining two structures as one include, but are not limited to:
• Phased development where one structure exists and another is planned.

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• Old and new structure types and compatibility (with phased corridor construction).
• Median width.
• Median barrier treatment options.
• Environmental contexts and regulations.
• Seismic conditions and load ratings.
• Bridge maintenance and inspection techniques: accessibility options and equipment
for terrain in specific contexts. An open area between structures may be needed for
bridge inspection.
• Skew angles and/or curvature of waterways or roadways beneath the structures.
• Economics.
• Historical/aesthetic value of existing bridges to remain in place.

If structures will not be joined, evaluate the median as described here:

When there is a median gap between bridges of 6 inches or more, the Region PEO will evaluate
whether or not the median gap needs to be screened. Address the potential for pedestrians on
the bridge and if closing the median gap to less than 6 inches, or installing fencing, netting, or
other elements to enclose the area between the bridges would be beneficial. Document this
evaluation in the Basis of Design and Alternatives Comparison Table.

Exhibit 720-1 Phased Development of Multilane Divided Highways

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720.03(5) Vertical Clearance

Vertical clearance is the critical height under a structure that will accommodate vehicular and
rail traffic based on its design characteristics. This height is the least height available from the
lower roadway surface (including usable shoulders) or the plane of the top of the rails to the
bottom of the bridge. Usable shoulders are the design shoulders for the roadway and do not
include paved widened areas that may exist under the structure.

In addition to the following vertical clearance guidance, consider whether the corridor
experiences overheight loads. Consider a vertical clearance such that it will not create a new
“low point” in the corridor.

720.03(5)(a) Vertical Falsework Clearance for Bridges Over Highways

Construction of new bridges and the reconstruction or widening of existing structures often
requires the erection of falsework across the traveled way of a highway. The erection of this
falsework can reduce the vertical clearance for vehicles to pass under the work area. The
potential for collisions to occur by hitting this lower construction stage falsework is increased.
1. On all routes that require a 16.5-foot vertical clearance, maintain this same clearance
for falsework vertical clearance.
• On structures that currently have less than a 16.5-foot vertical clearance for the
falsework envelope, maintain existing clearance.
• On new structures, maintain the falsework vertical clearance at least to those of
the minimum vertical clearances referenced below.
2. Any variance from the above must be approved by the Regional Administrator or
designee in writing and made a part of the Project File.
720.03(5)(b) Minimum Clearance for New Structures

For new structures, the minimum vertical clearances are as follows:

720.03(5)(b)(1) Bridge Over a Roadway

The minimum vertical clearance for a bridge over a roadway is 16.5 feet.

720.03(5)(b)(2) Bridge Over a Railroad Track

The minimum vertical clearance for a bridge over a railroad track is 23.5 feet (see Exhibit
720-2). A lesser clearance may be negotiated with the railroad company based on certain
operational characteristics of the rail line; however, any clearance less than 22.5 feet
requires the approval of the Washington State Utilities and Transportation Commission
(WUTC) per WAC 480-60. Vertical clearance is provided for the width of the railroad
clearance envelope. Coordinate railroad clearance issues with the HQ Design Office Railroad
Liaison.

720.03(5)(b)(3) Pedestrian Bridge Over a Roadway

The minimum vertical clearance for a pedestrian bridge over a roadway is 17.5 feet.

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Exhibit 720-2 Highway Structure Over Railroad

Notes:
 Use 22.5-foot vertical clearance for existing structures.
 Lesser vertical clearance may be negotiated (see 720.03(5)).
 Increase horizontal clearance when the track is curved.
 Coordinate railroad clearance issues with the HQ Design Office Railroad Liaison.

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720.03(5)(c) Minimum Clearance for Existing Structures

The criteria used to evaluate the vertical clearance for existing structures depend on the work
being done on or under that structure. When evaluating an existing structure on the Interstate
System, see 720.03(5)(e), Coordination. This guidance applies to bridge clearances over state
highways and under state highways at interchanges. For state highways over local roads and
streets, city or county vertical clearance requirements may be used as minimum design criteria.
(See Exhibit 720-3 for bridge vertical clearances.)
720.03(5)(c)(1) Bridge Over a Roadway

For a project that will widen an existing structure over a highway or where the highway will
be widened under an existing structure, the vertical clearance can be as little as 16.0 feet on
the Interstate System or other freeways or 15.5 feet on nonfreeway routes. An approved
design analysis is required for clearance less than 16.0 feet on Interstate routes or other
freeways and 15.5 feet on nonfreeway routes.

For a planned resurfacing of the highway under an existing bridge, if the clearance will be
less than 16.0 feet on the Interstate System or other freeways and 15.5 feet on nonfreeway
routes, evaluate the following options and include in a design analysis request:
 Pavement removal and replacement
 Roadway excavation and reconstruction to lower the roadway profile
 Providing a new bridge with the required vertical clearance

Reducing roadway paving and surfacing thickness under the bridge to achieve the minimum
vertical clearance can cause accelerated deterioration of the highway and is not
recommended. Elimination of the planned resurfacing in the immediate area of the bridge
might be a short-term solution if recommended by the Region Materials Engineer (RME).
Solutions that include milling the existing surface followed by overlay or inlay must be
approved by the RME to ensure adequate pavement structure is provided.

For other projects that include an existing bridge where no widening is proposed on or
under the bridge, and the project does not affect vertical clearance, the clearance can be as
little as 14.5 feet. For these projects, document the clearance in the Design Documentation
Package. For an existing bridge with less than a 14.5-foot vertical clearance, an approved
design analysis request is required.

720.03(5)(c)(2) Bridge Over a Railroad Track

For an existing structure over a railroad track (see Exhibit 720-2), the vertical clearance can
be as little as 22.5 feet. A lesser clearance can be used with the agreement of the railroad
company and the approval of the Washington State Utilities and Transportation
Commission. Coordinate railroad clearance issues with the HQ Design Office Railroad
Liaison.

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Exhibit 720-3 Bridge Vertical Clearances

Documentation
Vertical
Project Type Requirement
Clearance [8]
(see notes)
Interstate and Other Freeways [1]
New Bridge > 16.5 ft [2]
> 16 ft [2]
Widening Over or Under Existing Bridge
< 16 ft [4]
> 16 ft [2]
Resurfacing Under Existing Bridge
< 16 ft [4]
> 14.5 ft [3]
Other With No Change to Vertical Clearance
< 14.5 ft [4]
Nonfreeway Routes
New Bridge > 16.5 ft [2]
> 15.5 ft [2]
Widening Over or Under Existing Bridge
< 15.5 ft [4]
> 15.5 ft [2]
Resurfacing Under Existing Bridge
< 15.5 ft [4]
> 14.5 ft [3]
Other With No Change to Vertical Clearance
< 14.5 ft [4]
Bridge Over Railroad Tracks [7]
> 23.5 ft [2]
New Bridge
< 23.5 ft [4][5]
> 22.5 ft [2]
Existing Bridge
< 22.5 ft [4][5]
Pedestrian Bridge Over Roadway
New Bridge > 17.5 ft [2]
Existing Bridge 17.5 ft [6]

Notes:
[1] Applies to all bridge vertical clearances over highways and under highways at interchanges.
[2] No documentation required.
[3] Document to Design Documentation Package.
[4] Approved design analysis required.
[5] Requires written agreement between railroad company and WSDOT and approval via
petition from the WUTC.
[6] Maintain 17.5-ft clearance.
[7] Coordinate railroad clearance with the HQ Design Office Railroad Liaison.
[8] See 720.03(5).

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720.03(5)(d) Signing

Low-clearance warning signs are necessary when the vertical clearance of an existing bridge is
less than 15 feet 3 inches. Refer to the Manual on Uniform Traffic Control Devices and the Traffic
Manual for other requirements for low-clearance signing.
720.03(5)(e) Coordination

The Interstate System is used by the Department of Defense (DOD) for the conveyance of
military traffic. The Military Traffic Management Command Transportation Engineering Agency
(MTMCTEA) represents the DOD in public highway matters. The MTMCTEA has an inventory of
vertical clearance deficiencies over the Interstate System in Washington State. Contact the
MTMCTEA, through the Federal Highway Administration (FHWA), if either of the following
changes is proposed to these bridges:
 A project would create a new deficiency of less than a 16.0-foot vertical clearance over
an Interstate highway.
 The vertical clearance over the Interstate is already deficient (less than 16.0 feet) and a
change (increase or decrease) to vertical clearance is proposed.

Coordination with MTMCTEA is required for these changes on all rural Interstate highways and
for one Interstate route through each urban area.

720.03(6) Liquefaction Impact Considerations

To determine the amount of settlement and the potential for the soil to flow laterally during the
design level earthquake due to liquefaction, an analysis performed by the HQ Geotechnical
Office is needed for each bridge project site location. The information collected is used by bridge
engineers to determine the bridge’s capability to withstand the movement and loading in a
seismic event and to explore other foundation mitigation options not necessitating total bridge
replacement.

The HQ Bridge and Structures Office, in collaboration with the HQ Geotechnical Office, evaluates
bridge-widening projects involving liquefiable soils and recommends appropriate liquefaction
mitigation.

See the Bridge Design Manual LRFD for further information.

720.03(7) Pedestrian and Bicycle Facilities

When pedestrians or bicyclists are anticipated on bridges, provide facilities consistent with
guidance in Chapters 1510, 1515, and 1520.

Evolving programs and technologies such as incident response, personal cell phones, and ITS
cameras have further reduced the probability of motorists becoming pedestrians. Investigate
other methods of treatment such as pedestrian scale signing or other low-cost safety
improvement measures. Document decisions in the Basis of Design.

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720.03(8) Bridge Approach Slab

Bridge approach slabs are reinforced concrete pavement installed across the full width of the
bridge ends. They provide a stable transition from normal roadway cross section to the bridge
ends, and they compensate for differential expansion and contraction of the bridge and the
roadway.

Bridge approach slabs are provided on all new bridges. If an existing bridge is being widened and
it has an approach slab, slabs are required on the widenings. The region, with the concurrence
of the State Geotechnical Engineer and the State Bridge Design Engineer, may decide to omit
bridge approach slabs. Document decisions in the DDP.

720.03(9) Traffic Barrier End Treatment

Plans for new bridge construction and bridge traffic barrier modifications include provisions for
the connection of bridge traffic barriers to the longitudinal barrier approaching and departing
the bridge. Indicate the preferred longitudinal barrier type and connection during the review of
the bridge preliminary plan.

720.03(10) Bridge End Embankments

The design of embankment slopes at bridge ends depends on several factors. The width of the
embankment is determined not only by the width of the roadway, but also by the presence of
traffic barriers, curbs, and sidewalks, all of which create the need for additional widening.
Examples of the additional widening required for these conditions are shown in the Standard
Plans.

The end slope is determined by combining the recommendations of several technical experts
within WSDOT. Exhibit 720-4 illustrates the factors taken into consideration and the experts
involved in the process.

720.03(11) Bridge Slope Protection

Slope protection provides a protective and aesthetic surface for exposed slopes under bridges.
Slope protection is normally provided under:
 Structures over state highways.
 Structures within an interchange.
 Structures over other public roads unless requested otherwise by the public agency.
 Railroad overcrossings if requested by the railroad.

Slope protection is usually not provided under pedestrian structures.

The type of slope protection is selected at the bridge preliminary plan stage. Typical slope
protection types are concrete slope protection, and rubble stone.

720.03(12) Slope Protection at Water Crossings

The HQ Hydraulics Section determines the slope protection requirements for structures that
cross waterways. The type, limits, and quantity of slope protection are shown on the bridge
preliminary plan.

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Exhibit 720-4 Embankment Slope at Bridge Ends

Legend
A = Superstructure depth: recommended by HQ Bridge and Structures Office
B = Vertical clearance from bottom of superstructure to embankment: recommended by Bridge
Preservation Engineer
C = Distance from end of retaining wall or wing wall to back of pavement seat: recommended by
HQ Bridge and Structures Office
H & V = Embankment slope: recommended by Geotechnical Engineer

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720.03(13) Screening for Highway Structures

The Washington State Patrol (WSP) classifies the throwing of an object from a highway structure
as an assault, not an accident or collision. Therefore, records of these assaults are not contained
in WSDOT’s crash databases. Contact the Region Traffic Engineer, RME’s office and the WSP for
the history of reported incidents.

Screening might reduce the number of incidents, but will not stop a determined individual at
that location, or deter them from moving to other locations in the area. Enforcement provides
the most effective deterrent and is typically the first approach used.

Installation of screening is analyzed on a case-by-case basis at the following locations:

 On existing structures where there is a history of multiple incidents of objects being
dropped or thrown and where enforcement has not changed the situation.
 On new structures near schools, playgrounds, or areas frequently used by children not
accompanied by adults.
 In urban areas on new structures used by pedestrians where surveillance by local law
enforcement personnel is not likely.
 On new structures with walkways where experience on similar structures within a 1
mile radius indicates a need.
 On private property structures, such as buildings or power stations, subject to damage.

In most cases, the installation of a screen on a new structure can be postponed until there are
indications of need.

Submit all proposals to install screening on structures to the Director & State Design Engineer,
Development Division, for approval. Contact the HQ Bridge and Structures Office for approval to
attach screening to structures and for specific design and mounting details.

720.04 Coordination with US Coast Guard for Existing Bridges

Existing bridges crossing navigable waters occasionally require construction or maintenance
activities that impact navigation channels governed by USCG permits. For fixed span bridges,
this may include construction or maintenance activities that infringe upon the horizontal and
vertical navigation opening defined in the USCG permit. For movable bridges, in addition to the
above, this may also include adjustments to existing bridge opening operating notice and
process as defined in current regulations.

Because these impacts are temporary and are limited to the duration of the construction or
maintenance activity, they do not affect or change the actual USCG bridge permit. However,
such temporary adjustments still require coordination with the US Coast Guard early in the
project design schedule.

The primary responsibility for this contact and coordination lies with the Region Design Project
Office. The scope of such coordination varies depending on the extent of the infringement into
the defined horizontal or vertical navigation clearance opening, the extent of the change to the
bridge operation notice or process as defined in current regulation, and the duration of the
construction or maintenance activity.

This coordination activity may require the Design Project Office to conduct a survey of waterway
users or to perform other background information tasks requested by the US Coast Guard.

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Projects with more extensive impacts may lie outside the approval authority of the local USCG
Commander and may require review and action by US Coast Guard HQ in Washington, DC. In all
cases, the earlier in the design process that the Region Design Project Office initiates these
coordination efforts, the more likely the USCG can complete their regulatory process without
impacting the project schedule.

720.05 Documentation
Refer to Chapter 300 for design documentation requirements.

720.06 References

720.06(1) Federal/State Laws and Codes

23 CFR Part 650, Subpart C – National Bridge Inspection Standards

Washington Administrative Code (WAC) 480-60*, Railroad companies – Clearances

*Note: railroads may have stricter clearances than what is required in law and each railroad
should be consulted as early as possible as to allowable clearances.

720.06(2) Design Guidance

Bridge Design Manual LRFD, M 23-50, WSDOT

Geotechnical Design Manual, M 46-03, WSDOT

Local Agency Guidelines (LAG), M 36-63, WSDOT

LRFD Bridge Design Specifications, AASHTO, Current Edition

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-10, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications),
M 41-10, WSDOT

Traffic Manual, M 51-02, WSDOT

720.06(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition

Manual for Railway Engineering, American Railway Engineering and Maintenance-of-Way

Association (AREMA)

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 Retaining Walls and
Chapter 730 Steep Reinforced Slopes
730.01 General
730.02 References
730.03 Design Principles
730.04 Design Requirements
730.05 Guidelines for Wall/Slope Selection
730.06 Design Responsibility and Process
730.07 Documentation

730.01 General
The function of a retaining wall is to form a nearly vertical face through confinement
and/or strengthening of a mass of earth or other bulk material. Likewise, the function
of a reinforced slope is to strengthen the mass of earth or other bulk material
such that a steep (up to 1H:2V) slope can be formed. In both cases, the purpose
of constructing such structures is to make maximum use of limited right of way.
The difference between the two is that a wall uses a structural facing, whereas a steep
reinforced slope does not require a structural facing. Reinforced slopes typically use
a permanent erosion control matting with low vegetation as a slope cover to prevent
erosion. (See the Roadside Manual for more information.)
To lay out and design a retaining wall or reinforced slope, consider the
following items:
• Functional classification
• Highway geometry
• Design Clear Zone requirements (see Chapter 1600)
• Amount of excavation required
• Traffic characteristics
• Constructability
• Impact to adjacent environmentally sensitive areas
• Impact to adjacent structures
• Potential added lanes
• Length and height of wall
• Material to be retained
• Foundation support and potential for differential settlement
• Groundwater
• Earthquake loads
• Right of way costs
• Need for construction easements
• Risk
• Overall cost
• Visual appearance
If the wall or toe of a reinforced slope is to be located adjacent to the right of way
line, consider the space needed in front of the wall/slope to construct it.

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(1) Retaining Wall Classifications

Retaining walls are generally classified as gravity, semigravity, nongravity cantilever,
or anchored. The various wall types and their classifications are summarized in
Exhibits 730-1 through 730-6.
(a) Gravity Walls
Gravity walls derive their capacity to resist lateral soil loads through
a combination of dead weight and sliding resistance. Gravity walls can be
further subdivided into rigid gravity walls, prefabricated modular gravity walls,
and mechanically stabilized earth (MSE) gravity walls.
Rigid gravity walls consist of a solid mass of concrete or mortared rubble,
and they use the weight of the wall itself to resist lateral loads.
Prefabricated modular gravity walls consist of interlocking soil or rock-filled
concrete, steel, or wire modules or bins (such as gabions). The combined weight
resists the lateral loads from the soil.
MSE gravity walls use strips, bars, or mats of steel or polymeric reinforcement
to reinforce the soil and create a reinforced soil block behind the face. The
reinforced soil block then acts as a unit and resists the lateral soil loads through
the dead weight of the reinforced mass. MSE walls may be constructed as fill
walls, with fill and reinforcement placed in alternate layers to create a reinforced
mass, or reinforcement may be drilled into an existing soil/rock mass using
grouted anchor technology to create a reinforced soil mass (soil nail walls).
(b) Semigravity Walls
Semigravity walls rely more on structural resistance through cantilevering action
of the wall stem. Generally, the backfill for a semigravity wall rests on part of the
wall footing. The backfill, in combination with the weight of the wall and footing,
provides the dead weight for resistance. An example of a semigravity wall is the
reinforced concrete wall provided in the Standard Plans.
(c) Nongravity Cantilever Walls
Nongravity cantilever walls rely strictly on the structural resistance of the wall
in which vertical elements of the wall are partially embedded in the soil or rock
to provide fixity. These vertical elements may consist of piles (such as soldier
piles or sheet piles), caissons, or drilled shafts. The vertical elements may form
the entire wall face or they may be spanned structurally using timber lagging
or other materials to form the wall face.
(d) Anchored Walls
Anchored walls derive their lateral capacity through anchors embedded in stable
soil or rock below or behind all potential soil/rock failure surfaces. Anchored
walls are similar to nongravity cantilevered walls except that anchors embedded
in the soil/rock are attached to the wall facing structure to provide lateral
resistance. Anchors typically consist of deadman or grouted soil/rock anchors.
Reinforced slopes are similar to MSE walls in that they also use fill and
reinforcement placed in alternate layers to create a reinforced soil mass.
However, the face is typically built at a 1.2H:1V to 1H:2V slope.

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Chapter 730 Retaining Walls and Steep Reinforced Slopes

Rockeries (rock walls) behave to some extent like gravity walls. However,
the primary function of a rockery is to prevent erosion of an oversteepened
but technically stable slope. Rockeries consist of large, well-fitted rocks stacked
on top of one another to form a wall.
An example of a rockery and reinforced slope is provided in Exhibit 730-10.

730.02 References
(1) Federal/State Laws and Codes
Washington Administrative Code (WAC) 296-155, Safety standards for
construction work

(2) Design Guidance

Bridge Design Manual, M 23-50, WSDOT
Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans),
M 21-01, WSDOT
Plans Preparation Manual, M 22-31, WSDOT
Roadside Manual, M 25-30, WSDOT

730.03 Design Principles

The design of a retaining wall or reinforced slope consists of the following
principal activities:
• Develop wall/slope geometry
• Provide adequate subsurface investigation
• Evaluate loads and pressures that will act on the structure
• Design the structure to withstand the loads and pressures
• Design the structure to meet aesthetic requirements
• Ensure wall/slope constructibility
• Coordinate with other design elements
The structure and adjacent soil mass also needs to be stable as a system,
and the anticipated wall settlement needs to be within acceptable limits.

730.04 Design Requirements

(1) Wall/Slope Geometry
Wall/slope geometry is developed considering the following:
• Geometry of the transportation facility itself
• Design Clear Zone requirements (see Chapter 1600)
• Flare rate and approach slope when inside the Design Clear Zone
(see Chapter 1610)
• Right of way constraints
• Existing ground contours
• Existing and future utility locations
• Impact to adjacent structures
• Impact to environmentally sensitive areas

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For wall/slope geometry, also consider the foundation embedment and type
anticipated, which requires coordination between the various design groups involved.
Retaining walls are designed to limit the potential for snagging vehicles by removing
protruding objects (such as bridge columns, light fixtures, or sign supports).
Provide a traffic barrier shape at the base of a new retaining wall constructed 12 feet
or less from the edge of the nearest traffic lane. The traffic barrier shape is optional
at the base of the new portion when an existing vertical-faced wall is being extended
(or the existing wall may be retrofitted for continuity). Depending on the application,
precast or cast-in-place Single Slope Concrete Barrier with vertical back or Type 4
Concrete Barrier may be used for both new and existing walls except when the
barrier face can be cast as an integral part of a new wall. Design analyses may be
considered, but they require approval as prescribed in Chapter 300. A design analysis
is not required where sidewalk exists in front of the wall or in other situations where
the wall face is otherwise inaccessible to traffic.

(2) Investigation of Soils

All retaining wall and reinforced slope structures require an investigation of the
underlying soil/rock that supports the structure. Chapter 610 provides guidance
on how to complete this investigation. A soil investigation is an integral part of
the design of any retaining wall or reinforced slope. The stability of the underlying
soils, their potential to settle under the imposed loads, the usability of any existing
excavated soils for wall/reinforced slope backfill, and the location of the groundwater
table are determined through the geotechnical investigation.

(3) Geotechnical and Structural Design

The structural elements of the wall or slope and the soil below, behind, and/or within
the structure are designed together as a system. The wall/slope system is designed
for overall external stability as well as internal stability. Overall external stability
includes stability of the slope the wall/reinforced slope is a part of and the local
external stability (overturning, sliding, and bearing capacity). Internal stability
includes resistance of the structural members to load and, in the case of MSE
walls and reinforced slopes, pullout capacity of the structural members or soil
reinforcement from the soil.
(a) Scour
At any location where a retaining wall or reinforced slope can be in contact
with water (such as a culvert outfall, ditch, wetland, lake, river, or floodplain),
there is a risk of scour at the toe. This risk must be analyzed. Contact the HQ
Geotechnical Office and HQ Hydraulics Office to determine whether a scour
analysis is required.

(4) Drainage Design

One of the principal causes of retaining wall/slope failure is the additional hydrostatic
load imposed by an increase in the water content in the material behind the wall or
slope. This condition results in a substantial increase in the lateral loads behind the
wall/slope since the material undergoes a possible increase in unit weight, water
pressure is exerted on the back of the wall, and the soil shear strength undergoes a
possible reduction. To alleviate this, adequate drainage for the retaining wall/slope

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Chapter 730 Retaining Walls and Steep Reinforced Slopes

needs to be considered in the design stage and reviewed by the region Materials
Engineer during construction. The drainage features shown in the Standard Plans are
the minimum basic requirements. Underdrains behind the wall/slope need to daylight
at some point in order to adequately perform their drainage function. Provide positive
drainage at periodic intervals to prevent entrapment of water.
Native soil may be used for retaining wall and reinforced slope backfill if it meets the
requirements for the particular wall/slope system. In general, use backfill that is free-
draining and granular in nature. Exceptions to this can be made depending on the site
conditions as determined by the Geotechnical Office of the Headquarters (HQ)
Materials Laboratory.
A typical drainage detail for a gravity wall (in particular, an MSE wall) is shown in
Exhibit 730-11. Include drainage details with a wall unless otherwise recommended
to be deleted by the Region Materials Engineer or HQ Geotechnical Office.

(5) Aesthetics
Retaining walls and slopes can have a pleasing appearance that is compatible with the
surrounding terrain and other structures in the vicinity. To the extent possible within
functional requirements and cost-effectiveness criteria, this aesthetic goal is to be met
for all visible retaining walls and reinforced slopes.
Aesthetic requirements include consideration of the wall face material, top profile,
terminals, and surface finish (texture, color, and pattern). Where appropriate, provide
planting areas and irrigation conduits. These will visually soften walls and blend
them with adjacent areas. Avoid short sections of retaining wall or steep slope
where possible.
In higher walls, variations in slope treatment are recommended for a pleasing
appearance. High continuous walls are generally not desirable from an aesthetic
standpoint, because they can be quite imposing. Consider stepping high or long
retaining walls in areas of high visibility. Plantings may be considered between
wall steps.
Approval by the State Bridge and Structures Architect is required on all retaining
wall aesthetics, including finishes, materials, and configuration (see Chapter 950).

(6) Constructability
Consider the potential effect that site constraints might have on the constructability
of the specific wall/slope. Constraints to be considered include but are not limited
to site geometry, access, time required to construct the wall, environmental issues,
and impact on traffic flow and other construction activities.

(7) Coordination With Other Design Elements

(a) Other Design Elements
Retaining wall and slope designs are to be coordinated with other elements of
the project that might interfere with or impact the design or construction of the
wall/slope. Also consider drainage features; utilities; luminaire or sign structures;
adjacent retaining walls or bridges; concrete traffic barriers; and beam guardrails.
Locate these design elements in a manner that will minimize the impacts to the
wall elements. In general, locate obstructions within the wall backfill (such as

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Retaining Walls and Steep Reinforced Slopes Chapter 730

guardrail posts, drainage features, and minor structure foundations) a minimum

of 3 feet from the back of the wall facing units.
Greater offset distances may be required depending on the size and nature
of the interfering design element. If possible, locate these elements to miss
reinforcement layers or other portions of the wall system. Conceptual details
for accommodating concrete traffic barriers and beam guardrails are provided
in Exhibit 730-12.
Where impact to the wall elements is unavoidable, the wall system needs to
be designed to accommodate these impacts. For example, it may be necessary
to place drainage structures or guardrail posts in the reinforced backfill zone of
MSE walls. This may require that holes be cut in the upper soil reinforcement
layers or that discrete reinforcement strips be splayed around the obstruction.
This causes additional load to be carried in the adjacent reinforcement layers due
to the missing soil reinforcement or the distortion in the reinforcement layers.
The need for these other design elements and their impacts on the proposed wall
systems are to be clearly indicated in the submitted wall site data so the walls
can be properly designed. Contact the HQ Bridge and Structures Office (or
the Geotechnical Office for geosynthetic walls/slopes and soil nail walls) for
assistance regarding this issue.
(b) Worker Fall Protection
Department of Labor and Industries regulations require that, when employees
are exposed to the possibility of falling from a location 4 feet or more above
the roadway (or other lower area), the employer is to ensure fall restraint or
fall arrest systems are provided, installed, and implemented.
Design fall protection in accordance with WAC 296-155-24609 for walls that
create a potential for a fall of 4 feet or more. During construction or other
temporary or emergency condition, fall protection will follow WAC 296-155.
Any need for maintenance of the wall’s surface or the area at the top can expose
employees to a possible fall. If the area at the top will be open to the public, see
Chapter 1510, Pedestrian Facilities.
For maintenance of a tall wall’s surface (10 feet or more), consider harness tie-
offs if other protective means are not provided.
For maintenance of the area at the top of a tall wall, a fall restraint system
is required when all of the following conditions will exist:
• A possible fall will be of 4 feet or more.
• Periodic maintenance will be performed on the area at the top.
• The area at the top is not open to the public.
Recommended fall restraint systems are:
• Wire rope railing with top and intermediate rails of ½-inch-diameter
steel wire rope.
• Steel pipe railing with 1½-inch nominal outside diameter pipe as
posts and top and intermediate rails.
• Concrete as an extension of the height of the retaining wall.

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A fall restraint system is to be 42 inches high, plus or minus 3 inches, measured

from the top of the finished grade, and capable of withstanding a 200 lb force
from any direction, at the top, with minimal deflection. An intermediate cable
or rail shall be halfway between the top rail and the platform. A toe board with
a minimum height of 4 inches will be provided. Post spacing is no more than
8 feet on centers. (See the Construction Manual and WAC 296-155 for fall
arrest and protection information.) For wire rope railing, the top railing shall be
flagged at not more than 6-foot intervals with high-visibility material.
The designer is to contact maintenance personnel regarding fall protection and
debris removal considerations.
Contact the HQ Bridge and Structures Office for design details for any retrofit
to an existing retaining wall and for any attachments to a new retaining wall.

730.05 Guidelines for Wall/Slope Selection

Wall/slope selection is dependent on:
• Whether the wall/slope will be located primarily in a cut or fill (how much
excavation/shoring will be required to construct the wall or slope).
• If located in a cut, the type of soil/rock present.
• The need for space between the right of way line and the wall/slope or easement.
• The amount of settlement expected.
• The potential for deep failure surfaces to be present.
• The structural capacity of the wall/slope in terms of maximum allowable height.
• The nature of the wall/slope application.
• Whether or not structures or utilities will be located on or above the wall.
• Architectural requirements.
• Overall economy.

(1) Cut and Fill Considerations

Due to the construction technique and base width required, some wall types are
best suited for cut situations, whereas others are best suited for fill situations. For
example, anchored walls and soil nail walls have soil reinforcements drilled into
the in-situ soil/rock and are therefore generally used in cut situations. Nongravity
cantilevered walls are drilled or cut into the in-situ soil/rock, have narrow base
widths, and are also well suited to cut situations. Both types of walls are constructed
from the top down. Such walls are also used as temporary shoring to allow other
types of walls or other structures to be constructed where considerable excavation
will otherwise be required.
MSE walls and reinforced slopes, however, are constructed by placing soil
reinforcement between layers of fill from the bottom up and are therefore best suited
to fill situations. Furthermore, the base width of MSE walls is typically on the order
of 70% of the wall height, which requires considerable excavation in a cut situation.
Therefore, in a cut situation, base width requirements usually make MSE structures
uneconomical and possibly unconstructible.
Semigravity (cantilever) walls, rigid gravity walls, and prefabricated modular gravity
walls are free-standing structural systems built from the bottom up, but they do not rely
on soil reinforcement techniques (placement of fill layers with soil reinforcement) to
provide stability.

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These types of walls generally have a narrower base width than MSE structures (on
the order of 50% of the wall height). Both of these factors make these types of walls
feasible in fill situations as well as many cut situations.
Reinforced slopes generally require more room overall to construct than a wall
because of the sloping face, but they typically are a feasible alternative to a
combination wall and fill slope to add a new lane. Reinforced slopes can also
be adapted to the existing ground contours to minimize excavation requirements
where fill is placed on an existing slope. Reinforced slopes might also be a feasible
choice to repair slopes damaged by landslide activity or deep erosion.
Rockeries are best suited to cut situations as they require only a narrow base width,
on the order of 30% of the rockery height. Rockeries can be used in fill situations,
but the fill heights they support need to be kept relatively low. It is difficult to get the
cohesive strength needed in granular fill soils to provide minimal stability of the soil
behind the rockery at the steep slope typically used for rockeries in a cut (such as
1H:6V or 1H:4V).
The key considerations in deciding which walls or slopes are feasible are the amount
of excavation or shoring required and the overall height. The site geometric constraints
are defined to determine these elements. Another consideration is whether or not an
easement will be required. For example, a temporary easement might be required for a
wall in a fill situation to allow the contractor to work in front of the wall. For walls in
cut situations, especially anchored walls and soil nail walls, a permanent easement may
be required for the anchors or nails.

(2) Settlement and Deep Foundation Support Considerations

Settlement issues, especially differential settlement, are of primary concern in the
selection of walls. Some wall types are inherently flexible and can tolerate a great
deal of settlement without suffering structurally. Other wall types are inherently
rigid and cannot tolerate much settlement. In general, MSE walls have the greatest
flexibility and tolerance to settlement, followed by prefabricated modular gravity
walls. Reinforced slopes are also inherently very flexible. For MSE walls, the facing
type used can affect the ability of the wall to tolerate settlement. Welded wire and
geosynthetic wall facings are the most flexible and the most tolerant to settlement,
whereas concrete facings are less tolerant to settlement. In some cases, after the wall
settlement is complete, concrete facing can be placed such that the concrete facing
does not limit the wall’s tolerance to settlement. Facing may also be added for
aesthetic reasons.
Semigravity (cantilever) walls and rigid gravity walls have the least tolerance to
settlement. In general, total settlement for these types of walls needs to be limited
to approximately 1 inch or less. Rockeries also cannot tolerate much settlement, as
rocks can shift and fall out. Therefore, semigravity cantilever walls, rigid gravity
walls, and rockeries are not used in settlement prone areas.
If very weak soils are present that will not support the wall and are too deep to be
overexcavated, or if a deep failure surface is present that results in inadequate slope
stability, select a wall type capable of using deep foundation support and/or anchors.
In general, MSE walls, prefabricated modular gravity walls, and some rigid gravity
walls are not appropriate for these situations. Walls that can be pile-supported, such
as concrete semigravity cantilever walls, nongravity cantilever walls, and anchored
walls, are more appropriate for these situations.

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(3) Feasible Wall Heights and Limitations

Feasible wall heights are affected by issues such as the capacity of the wall structural
elements, past experience with a particular wall, current practice, seismic risk, long-
term durability, and aesthetics.
For height limitations, see Exhibits 730-1 through 730-6.

(4) Supporting Structures or Utilities

Not all walls are acceptable to support other structures or utilities. Issues that are
to be considered include the potential for the wall to deform due to the structure
foundation load, interference between the structure foundation and the wall
components, and the potential long-term durability of the wall system. Using
retaining walls to support other structures is considered to be a critical application,
requiring a special design. In general, soil nail walls, semigravity cantilever walls,
nongravity cantilever walls, and anchored walls are appropriate for use in supporting
bridge and building structure foundations. In addition to these walls, MSE and
prefabricated modular gravity walls may be used to support other retaining walls,
noise walls, and minor structure foundations such as those for sign bridges and
signals. On a project-specific basis, MSE walls can be used to support bridge and
building foundations as approved by the HQ Bridge and Structures Office.
Consider the location of any utilities behind the wall or reinforced slope when
making wall/slope selections. This is mainly an issue for walls that use some type
of soil reinforcement and for reinforced slopes. It is best not to place utilities within
a reinforced soil backfill zone because it will be impossible to access the utility from
the ground surface without cutting through the soil reinforcement layers, thereby
compromising the integrity of the wall.
Sometimes utilities, culverts, pipe arches, and so on must penetrate the face of a wall.
Not all walls and facings are compatible with such penetrations. Consider how
the facing can be formed around the penetration so that backfill soil cannot pipe
or erode through the face. Contact the HQ Bridge and Structures Office for assistance
regarding this issue.

(5) Facing Options

Facing selection depends on the aesthetic and structural needs of the wall system.
Wall settlement may also affect the feasibility of the facing options. More than
one wall facing may be available for a given system. Consider the available facing
options when selecting a particular wall.
(a) MSE Walls
For MSE walls, facing options typically include:
• Precast modular panels.
• In some cases, full height precast concrete panels. Full height panels are
generally limited to walls with a maximum height of 20 feet placed in areas
where minimal settlement is expected.
• Welded wire facing.
• Timber facing.
• Shotcrete facing with treatment options that vary from a simple broom finish
to a textured and colored finish.

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• Segmental masonry concrete blocks.

• Cast-in-place concrete facing with various texturing options.
Plantings on welded wire facings can be attempted in certain cases. The difficulty
is in providing a soil at the wall face that is suitable for growing plants and meets
engineering requirements in terms of soil compressibility, strength, and drainage.
If plantings in the wall face are attempted, use only small plants, vines, and
grasses. Small bushes may be considered for plantings between wall steps. Larger
bushes or trees are not considered in these cases due to the loads they can create
on the wall face.
Geosynthetic facings are not acceptable for permanent facings due to potential
facing degradation when exposed to sunlight. For permanent applications, use
some type of timber, welded wire, or concrete face for geosynthetic walls.
Shotcrete, masonry concrete blocks, cast-in-place concrete, welded wire,
or timber are typically used for geosynthetic wall facings.
(b) Soil Nail Walls
Soil nail walls can use either architecturally treated shotcrete or a cast-in-place
facia wall textured as needed to produce the desired appearance.
(c) Prefabricated Modular Gravity Walls
For prefabricated modular gravity walls, the facing generally consists of the
structural bin or crib elements used to construct the walls. For some walls, the
elements can be rearranged to form areas for plantings. In some cases, textured
structural elements might also be feasible. This is also true of rigid gravity walls,
though planting areas on the face of rigid gravity walls are generally not feasible.
The concrete facing for semigravity cantilever walls can be textured as needed
to produce the desired appearance.
(d) Nongravity Cantilevered Walls
For nongravity cantilevered walls and anchored walls, a textured cast-in-place
or precast facia wall is usually installed to produce the desired appearance.

(6) Cost Considerations

Usually, more than one wall type is feasible for a given situation. Consider initial and
future maintenance costs throughout the selection process, as the decisions made may
affect the overall cost. For example, you may have to decide whether to shut down
a lane of traffic to install a low-cost gravity wall system that requires more excavation
room or use a more expensive anchored wall system that will minimize excavation
requirements and impacts to traffic. In this case, determine whether the cost of traffic
impacts and more excavation justifies the cost of the more expensive anchored wall
system. Consider long-term maintenance costs when determining wall type.
Decisions regarding aesthetics can also affect the overall cost of the wall system.
In general, the least expensive aesthetic options use the structural members of the
wall as facing (welded wire or concrete or steel cribbing or bins), whereas the most
expensive aesthetic options use textured cast-in-place concrete facias. In general,
concrete facings increase in cost in the following order: shotcrete, segmental masonry
concrete blocks, precast concrete facing panels, full height precast concrete facing
panels, and cast-in-place concrete facing panels. Special architectural treatments

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usually increase the cost of any of these facing systems. Special wall terracing
to provide locations for plants will also tend to increase costs. Therefore, weigh the
costs against the value of the desired aesthetics.
Other factors that affect the costs of wall/slope systems include wall/slope size and
length; access at the site and distance to the material supplier location; overall size
of the project; and competition between wall suppliers. In general, costs tend to be
higher for walls or slopes that are high, but short in length, due to lack of room for
equipment to work. Sites that are remote or have difficult local access increase wall/
slope costs. Small wall/slope quantities result in high unit costs. Lack of competition
between materials or wall system suppliers can result in higher costs as well.
Some of the factors that increase costs are required parts of a project and are
therefore unavoidable. Always consider such factors when estimating costs because
a requirement may not affect all wall types in the same way. Current cost information
can be obtained by consulting the Bridge Design Manual or by contacting the HQ
Bridge and Structures Office.

(7) Summary
For wall/slope selection, consider factors such as the intended application; the soil/
rock conditions in terms of settlement, need for deep foundations, constructibility,
and impacts to traffic; and the overall geometry in terms of wall/slope height and
length, location of adjacent structures and utilities, aesthetics, and cost. Exhibits
730-1 through 730-6 provide a summary of many of the various wall/slope options
available, including their advantages, disadvantages, and limitations. Note that
specific wall types in the exhibits may represent multiple wall systems, some or all
of which will be proprietary.

730.06 Design Responsibility and Process

(1) General
The retaining walls available for a given project include standard walls, nonstandard
walls, and reinforced slopes.
Standard walls are those walls for which standard designs are provided in the
Washington State Department of Transportation (WSDOT) Standard Plans. These
designs are provided for reinforced concrete cantilever walls up to 35 feet in height.
The internal stability design and the external stability design for overturning and
sliding stability have already been completed for these standard walls. Determine
overall slope stability and allowable soil bearing capacity (including settlement
considerations) for each standard-design wall location.
Nonstandard walls may be either proprietary (patented or trademarked) or
nonproprietary. Proprietary walls are designed by a wall manufacturer for internal
and external stability, except bearing capacity, settlement, and overall slope stability,
which are determined by WSDOT. Nonstandard nonproprietary walls are fully
designed by WSDOT.
The geosynthetic soil reinforcement used in nonstandard nonproprietary geosynthetic
walls is considered to be proprietary. It is likely that more than one manufacturer can
supply proprietary materials for a nonstandard nonproprietary geosynthetic wall.
Reinforced slopes are similar to nonstandard nonproprietary walls in terms of their
design process.

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(a) Preapproved Proprietary Walls

Some proprietary wall systems are preapproved. Preapproved proprietary wall
systems have been extensively reviewed by the HQ Bridge and Structures Office
and the Geotechnical Office. Design procedures and wall details for preapproved
walls have already been agreed upon between WSDOT and the proprietary wall
manufacturers, allowing the manufacturers to competitively bid a particular
project without having a detailed wall design provided in the contract plans.
Note that proprietary wall manufacturers might produce several retaining wall
options, and not all options from a given manufacturer have necessarily been
preapproved. For example, proprietary wall manufacturers often offer more
than one facing alternative. It is possible that some facing alternatives are
preapproved, whereas others are not preapproved. WSDOT does not preapprove
the manufacturer, but specific wall systems by a given manufacturer can
be preapproved.
It is imperative with preapproved systems that the design requirements for
all preapproved wall alternatives for a given project be clearly stated so that
the wall manufacturer can adapt the preapproved system to specific project
conditions. For a given project, coordination of the design of all wall alternatives
with all project elements that impact the wall is critical to avoid costly change
orders or delays during construction. These elements include drainage features,
utilities, luminaires and sign structures, noise walls, traffic barriers, guardrails,
or other walls or bridges.
In general, standard walls are the easiest walls to incorporate into project Plans,
Specifications, and Estimates (PS&E), but they may not be the most cost-
effective option. Preapproved proprietary walls provide more options in terms
of cost-effectiveness and aesthetics and are also relatively easy to incorporate
into a PS&E. Nonstandard state-designed walls and nonpreapproved proprietary
walls generally take more time and effort to incorporate into a PS&E because
a complete wall design needs to be developed. Some nonstandard walls (such
as state-designed geosynthetic walls) can be designed relatively quickly, require
minimal plan preparation effort, and only involve the region and the Geotechnical
Office. Other nonstandard walls such as soil nail and anchored wall systems
require complex designs, involve both the HQ Bridge and Structures Office
and Geotechnical Office, and require a significant number of plan sheets and
considerable design effort.
The HQ Bridge and Structures Office maintains a list of the proprietary retaining
walls that are preapproved. The region consults the HQ Bridge and Structures
Office for the latest list. The region consults the HQ Geotechnical Office for the
latest geosynthetic reinforcement list to determine which geosynthetic products
are acceptable if a critical geosynthetic wall or reinforced slope application is
anticipated.
(b) Experimental Wall Systems
Some proprietary retaining wall systems are classified as experimental by the
Federal Highway Administration (FHWA). The HQ Bridge and Structures Office
maintains a list of walls that are classified as experimental. If the wall intended

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for use is classified as experimental, a work plan is to be prepared by WSDOT

and approved by the FHWA.
An approved public interest finding, signed by the Director & State Design
Engineer, Development Division, is required for the use of a sole source
proprietary wall.
(c) Gabion Walls
Gabion walls are nonstandard walls that are to be designed for overturning,
sliding, overall slope stability, settlement, and bearing capacity. A full design for
gabion walls is not provided in the Standard Plans. Gabion baskets are typically
3 feet high by 3 feet wide, and it is typically safe to build gabions two baskets
high (6 feet) but only one basket deep. This results in a wall base width of 50%
of the wall height, provided soil conditions are reasonably good (medium-dense
to dense granular soils are present below and behind the wall).

(2) Responsibility and Process for Design

A flow chart illustrating the process and responsibility for retaining wall/reinforced
slope design is provided in Exhibit 730-13a. As shown in the exhibit, the region
initiates the process except for walls developed as part of a preliminary bridge plan.
These are initiated by the HQ Bridge and Structures Office. In general, it is the
responsibility of the design office initiating the design process to coordinate with
other groups in the department to identify all wall/slope systems that are appropriate
for the project in question. Coordinate with the region and the HQ Bridge and
Structures Office, Geotechnical Office, and State Bridge and Structures Architect
as early in the process as feasible.
Headquarters or region consultants, if used, are considered an extension of the
Headquarters staff and must follow the process summarized in Exhibit 730-13a.
All consultant designs, from development of the scope of work to the final product,
are to be reviewed and approved by the appropriate Headquarters offices.
(a) Standard Walls
The regions are responsible for detailing retaining walls for which standard
designs are available.
For standard walls greater than 10 feet in height, and for all standard walls
where soft or unstable soil is present beneath or behind the wall, a geotechnical
investigation will be conducted, or reviewed and approved, by the HQ
Geotechnical Office. Through this investigation, provide the foundation design,
including bearing capacity requirements and settlement determination, overall
stability, and the selection of the wall types most feasible for the site.
For standard walls 10 feet in height or less where soft or unstable soils are not
present, it is the responsibility of the region Materials Laboratory to perform the
geotechnical investigation. If it has been verified that soil conditions are adequate
for the proposed standard wall that is less than or equal to 10 feet in height, the
region establishes the wall footing location based on the embedment criteria in
the Bridge Design Manual, or places the bottom of the wall footing below any
surficial loose soils. During this process, the region also evaluates other wall
types that may be feasible for the site in question.

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The Standard Plans provides design charts and details for standard reinforced
concrete cantilever walls. The Standard Plans are used to size the walls and
determine the factored bearing pressure to compare with the factored bearing
resistance determined from the geotechnical investigation. The charts provide
maximum soil pressure for the LRFD service, strength, and extreme event limit
states. Factored bearing resistance for the LRFD service, strength, and extreme
event limit states can be obtained from the HQ Geotechnical Office for standard
walls over 10 feet in height and from the region Materials Laboratory for
standard walls less than or equal to 10 feet in height. The Standard Plans can be
used for the wall design if the factored bearing resistance exceeds the maximum
soil pressure shown in the Standard Plans for the respective LRFD limit states.
Contact the HQ Bridge and Structures Office if the factored bearing resistance
provided by the geotechnical investigation does not exceed the maximum soil
pressure shown in the Standard Plans for one or all of the LRFD limit states.
The wall is considered a nonstandard wall design and the Standard Plans
cannot be used.
If the standard wall must support surcharge loads from bridge or building
foundations, other retaining walls, noise walls, or other types of surcharge
loads, a special wall design is required. The wall is considered to be supporting
the surcharge load and is treated as a nonstandard wall if the surcharge load
is located within a 1H:1V slope projected up from the bottom of the back of
the wall. Contact the HQ Bridge and Structures Office for assistance
The Standard Plans provides eight types of reinforced concrete cantilever walls
(which represent eight loading cases). Reinforced concrete retaining walls
Types 5 through 8 are not designed to withstand western Washington earthquake
forces and are not to be used in western Washington (west of the Cascade crest).
Once the geotechnical and architectural assessments have been completed, the
region completes the PS&E for the standard wall option(s) selected, including
a generalized wall profile and plan, a typical cross section as appropriate,
and details for desired wall appurtenances, drainage details, and other details
as needed.
Metal bin walls, Types 1 and 2, have been deleted from the Standard Plans
and are therefore no longer standard walls. Metal bin walls are seldom used
due to cost and undesirable aesthetics. If this type of wall is proposed, contact
the HQ Bridge and Structures Office for plan details and toe bearing pressures.
The applied toe bearing pressure will then have to be evaluated by the HQ
Geotechnical Office to determine whether the site soil conditions are appropriate
for the applied load and anticipated settlement.
(b) Preapproved Proprietary Walls
Final approval of preapproved proprietary wall design, with the exception
of geosynthetic walls, is the responsibility of the HQ Bridge and Structures
Office. Final approval of the design of preapproved proprietary geosynthetic
walls is the responsibility of the HQ Geotechnical Office. It is the region’s
responsibility to coordinate the design effort for all preapproved wall systems.

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The region Materials Laboratory performs the geotechnical investigation for

preapproved proprietary walls 10 feet in height or less that are not bearing on soft
or unstable soils. In all other cases, it is the responsibility of the HQ Geotechnical
Office to conduct, or review and approve, the geotechnical investigation for the
wall. The region also coordinates with the State Bridge and Structures Architect
to ensure that the wall options selected meet the aesthetic requirements for the
site.
Once the geotechnical and architectural assessments have been completed
and the desired wall alternatives selected, it is the responsibility of the region
to contact the suppliers of the selected preapproved systems to confirm in
writing the adequacy and availability of the systems for the proposed use.
Include a minimum of three different wall systems in the PS&E for any project
with federal participation that includes a proprietary wall system unless specific
justification is provided. Standard walls can be alternatives.
Once confirmation of adequacy and availability has been received, the region
contacts the HQ Bridge and Structures Office for special provisions for the
selected wall systems and proceeds to finalize the contract PS&E in accordance
with the Plans Preparation Manual. Provide the allowable bearing capacity and
foundation embedment criteria for the wall, as well as backfill and foundation
soil properties, in the Special Provisions. In general, assume that gravel borrow
or better-quality backfill material will be used for the walls when assessing
soil parameters.
Complete wall plans and designs for the proprietary wall options will not
be developed until after the contract is awarded, but will be developed by
the proprietary wall supplier as shop drawings after the contract is awarded.
Therefore, include a general wall plan; a profile showing neat line top and
bottom of the wall; a final ground line in front of and in back of the wall; a
typical cross-section; and the generic details for the desired appurtenances and
drainage requirements in the contract PS&E for the proprietary walls. Estimate
the ground line in back of the wall based on a nominal 1.5-foot facing thickness
(and state this on the wall plan sheets). Include load or other design acceptance
requirements for these appurtenances in the PS&E. Contact the HQ Bridge and
Structures Office for assistance.
It is best to locate catch basins, grate inlets, signal foundations, and the like
outside the reinforced backfill zone of MSE walls to avoid interference with
the soil reinforcement. In those cases where conflict with these reinforcement
obstructions cannot be avoided, indicate the location(s) and dimensions of the
reinforcement obstruction(s) relative to the wall on the plans. Contact the HQ
Bridge and Structures Office for preapproved wall details and designs for size
and location of obstructions and to obtain the generic details that are to be
provided in the plans. If the obstruction is too large or too close to the wall face,
a special design may be required to accommodate the obstruction, and the wall
is treated as a nonpreapproved proprietary wall.
A special design is required if the wall will support structure foundations, other
retaining walls, noise walls, signs or sign bridges, luminaires, or other types
of surcharge loads. The wall is considered to be supporting the surcharge load
if the surcharge is located within a 1H:1V slope projected from the bottom of the

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back of the wall. For MSE walls, the back of the wall is considered to be the
back of the soil reinforcement layers. If this situation occurs, the wall is treated
as a nonpreapproved proprietary wall.
For those alternative wall systems that have the same face embedment criteria,
the wall face quantities depicted in the plans for each alternative are to be
identical. To provide an equal basis for competition, the region determines
wall face quantities based on neat lines.
Once the detailed wall plans and designs are available as shop drawings after
contract award, the HQ Bridge and Structures Office will review and approve
the wall shop drawings and calculations, with the exception of geosynthetic
walls. They are reviewed and approved by the HQ Geotechnical Office.
(c) Nonpreapproved Proprietary Walls
Final approval authority for nonpreapproved proprietary wall design is the same
as for preapproved proprietary walls. The region initiates the design effort for
all nonpreapproved wall systems by submitting wall plan, profile, cross section,
and other information for the proposed wall to the HQ Bridge and Structures
Office, with copies to the HQ Geotechnical Office and the State Bridge and
Structures Architect. The HQ Bridge and Structures Office coordinates the
wall design effort.
Once the geotechnical and architectural assessments have been completed and
the desired wall types selected, the HQ Bridge and Structures Office contacts
suppliers of the selected nonpreapproved wall systems to obtain and review
detailed wall designs and plans to be included in the contract PS&E.
To ensure fair competition between all wall alternatives included in the PS&E,
make the wall face quantities identical for those wall systems subject to the
same face embedment requirements.
The HQ Bridge and Structures Office develops the special provisions and
cost estimates for the nonpreapproved proprietary walls and sends the wall
PS&E to the region for inclusion in the final PS&E in accordance with the
Plans Preparation Manual.
(d) Nonstandard Nonproprietary Walls
With the exception of rockeries over 5 feet high, nonproprietary geosynthetic
walls and reinforced slopes, and soil nail walls, the HQ Bridge and Structures
Office coordinates with the HQ Geotechnical Office and the State Bridge and
Structures Architect to carry out the design of all nonstandard, nonproprietary
walls. The HQ Bridge and Structures Office develops the wall preliminary plan
from site data provided by the region, completes the wall design, and develops
the nonstandard nonproprietary wall PS&E package for inclusion in the contract.
For rockeries over 5 feet high, nonproprietary geosynthetic walls and reinforced
slopes, and soil nail walls, the region develops wall/slope profiles, plans, and
cross sections and submits them to the HQ Geotechnical Office to complete
a detailed wall/slope design.
For geosynthetic walls and slopes and for rockeries, the region provides overall
coordination of the wall/slope design effort, including coordination with the
State Bridge and Structures Architect regarding aesthetics and finishes, and
the region or HQ Landscape Architect if the wall uses vegetation on the face.

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Chapter 730 Retaining Walls and Steep Reinforced Slopes

The HQ Geotechnical Office has overall approval authority for the wall design.
Once the wall design has been completed, the HQ Geotechnical Office, and in
some cases the HQ Bridge and Structures Office, provides geotechnical and
structural plan details to be included in the region plan sheets and special
provisions for the PS&E. The region then completes the PS&E package.
For soil nail walls, once the HQ Geotechnical Office has performed the
geotechnical design, the HQ Bridge and Structures Office, in cooperation
with the HQ Geotechnical Office, coordinates the design effort and completes
the PS&E package.

(3) Guidelines for Wall/Slope Data Submission for Design

(a) Standard Walls, Proprietary Walls, Geosynthetic Walls/Slopes, and
Soil Nail Walls
Where Headquarters involvement in retaining wall/slope design is required
(as it is for standard walls and preapproved proprietary walls over 10 feet
in height, gabions over 6 feet in height, rockeries over 5 feet in height, all
nonpreapproved proprietary walls, geosynthetic walls/slopes, and all soil nail
walls), the region submits the following information to the HQ Geotechnical
Office or HQ Bridge and Structures Office as appropriate:
• Wall/slope plans.
• Profiles showing the existing and final grades in front of and behind the
wall.
• Wall/slope cross sections (typically every 50 feet) or InRoads files that
define the existing and new ground line above and below the wall/slope
and show stations and offsets.
• Location of right of way lines and other constraints to wall/slope
construction.
• Location of adjacent existing and/or proposed structures, utilities,
and obstructions.
• Desired aesthetics.
• Date design must be completed.
• Key region contacts for the project.
Note that for the purpose of defining the final wall geometry, it is best to base
existing ground measurements on physical survey data rather than solely
on photogrammetry. In addition, the region is to complete a Retaining Wall/
Reinforced Slope Site Data Check List, DOT Form 351-009 EF, for each wall
or group of walls submitted.
(b) Nonstandard Walls, Except Geosynthetic Walls/Slopes and Soil Nail Walls
In this case, the region is to submit site data in accordance with Chapter 710.
Additionally, the region is to complete a Retaining Wall/Reinforced Slope Site
Data Check List, DOT Form 351-009 EF, for each wall or group of walls.

730.07 Documentation
Refer to Chapter 300 for design documentation requirements.

WSDOT Design Manual M 22-01.11 Page 730-17

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Retaining Walls and Steep Reinforced Slopes Chapter 730

Specific
Advantages Disadvantages Limitations
Wall Type
Steel soil Relatively low Can tolerate little settlement; Applicable primarily to fill
reinforcement with cost. generally requires high- situations; maximum feasible
full height precast quality backfill; wide base height is approximately
concrete panels width required (70% of 20 feet.
wall height).
Steel soil Relatively low Generally requires high-quality Applicable primarily to fill
reinforcement with cost; flexible backfill; wide base width situations; maximum height
modular precast enough to handle required (70% of wall height). of 33 feet; heights over
concrete panels significant 33 feet require a special
settlement. design.
Steel soil Can tolerate Relatively high cost; cannot Applicable primarily to fill
reinforcement large short-term tolerate long-term settlement; situations; maximum height
with welded wire settlements. generally requires high- of 33 feet for routine designs;
and cast-in-place quality wall backfill soil; wide heights over 33 feet require
concrete face base width required (70% a special design.
of wall height); typically
requires a settlement delay
during construction.
Steel soil Can tolerate Aesthetics, unless face Applicable primarily to fill
reinforcement large short-term plantings can be established; situations; maximum height
with welded wire settlements; generally requires high- of 33 feet for routine designs;
face only low cost. quality backfill; wide base heights over 33 feet require
width required (70% of a special design.
wall height).
Segmental Low cost; flexible Internal wall deformations Applicable primarily to fill
masonry concrete enough to handle may be greater for steel situations; in general, limited
block-faced walls, significant reinforced systems, but to a wall height of 20 feet
generally with settlement. are acceptable for most or less; greater wall heights
geosynthetic soil applications; generally may be feasible by special
reinforcement requires high-quality backfill; design in areas of low
wide base required (70% of seismic activity and when
wall height). geosynthetic products are
used in which long-term
product durability is well
defined. (See Qualified
Products List.)
Geosynthetic walls Very low cost, Internal wall deformations Applicable primarily to fill
with a shotcrete especially with may be greater than for situations; in general, limited
or cast-in-place shotcrete face; steel reinforced systems, to wall height of 20 feet
concrete face can tolerate but are still acceptable for or less unless using
large short-term most applications; generally geosynthetic products in
settlements. requires high-quality backfill; which long-term product
wide base width required durability is well defined.
(70% of wall height). (See Qualified Products
List.) For qualified products,
heights of 33 feet or more
are possible.

Summary of Mechanically Stabilized Earth (MSE) Gravity

Wall/Slope Options Available
Exhibit 730-1

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Chapter 730 Retaining Walls and Steep Reinforced Slopes

Specific
Advantages Disadvantages Limitations
Wall Type
Geosynthetic walls Very low cost; can Internal wall deformations Applicable primarily to fill
with a welded tolerate large long- may be greater than for situations; in general,
wire face term settlements. steel reinforced systems, limited to wall height
but are still acceptable for of 20 feet or less unless
most applications; generally using geosynthetic products
requires high-quality wall in which long-term product
backfill soil; wide base durability is well defined.
width required (70% of (See Qualified Products
wall height). List.) For qualified products,
heights of 33 feet or more
are possible.
Geosynthetic walls Lowest cost of all Internal wall deformations Applicable primarily to fill
with a geosynthetic wall options; can may be greater than for situations; use only for
face tolerate large long- steel reinforced systems, temporary applications due
term settlements. but are still acceptable for to durability of facing; can
most applications; generally be designed for wall heights
requires high-quality backfill; of 40 feet or more.
wide base width required
(70% of wall height);
durability of wall facing.
Soil nail walls Relatively low cost; Allow adequate standup Applicable to cut situations
can be used in time for soil/rock to stand in only; not recommended
areas with restricted a vertical cut approximately in clean or water-bearing
overhead or lateral 6 feet high for at least sands and gravels,
clearance. 1 to 2 days; not feasible for in bouldery soils that
bouldery soils; may require can interfere with nail
an easement for the nails. installation, or in landslide
deposits, especially where
deep potential failure
surfaces are present;
maximum wall heights
of 35 feet are feasible,
though greater wall heights
are possible in excellent
soil/rock conditions. A
special design is always
required.

Summary of Mechanically Stabilized Earth (MSE) Gravity

Wall/Slope Options Available
Exhibit 730-1 (continued)

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Retaining Walls and Steep Reinforced Slopes Chapter 730

Specific
Advantages Disadvantages Limitations
Wall Type
Concrete crib walls Relatively low cost; Aesthetics. Applicable to cut and
quantity of high- fill situations; reinforced
quality backfill concrete typically can be
required relatively designed for heights of up
small; relatively to 33 feet and unreinforced
narrow base concrete up to 16 feet; not
width, on the order used to support bridge
of 50 to 60% of the or building foundations.
wall height; can
tolerate moderate
settlements.
Metal crib walls Quantity of high- Relatively high cost; Applicable to cut and fill
quality backfill aesthetics. situations; can be designed
required relatively routinely for heights
small; relatively up to 35 feet; not used
narrow base to support bridge or building
width, on the order foundations.
of 50 to 60% of the
wall height; can
tolerate moderate
settlements.
Timber crib walls Low cost; minimal Design life relatively short; Applicable to cut and fill
high-quality backfill aesthetics. situations; can be designed
required; relatively for heights up to 16 feet; not
narrow base used to support structure
width, on the order foundations.
of 50 to 60% of the
wall height; can
tolerate moderate
settlements.
Concrete bin walls Relatively low cost; Aesthetics. Applicable to cut and fill
narrow base situations; can be designed
width, on the order routinely for heights
of 50 to 60% of the up to 25 feet; not used
wall height; can to support bridge or building
tolerate moderate foundations.
settlements.

Gabion walls Relatively narrow Relatively high cost, Applicable to cut and fill
base width, depending on proximity situations; can be designed
on the order to source of high-quality routinely for heights up
of 50 to 60% of the angular rock to fill baskets. to 15 feet, and by special
wall height; can design up to 21 feet; not
tolerate moderate used to support structure
settlements. foundations.

Summary of Prefabricated Modular Gravity Wall Options Available

Exhibit 730-2

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Chapter 730 Retaining Walls and Steep Reinforced Slopes

Specific
Advantages Disadvantages Limitations
Wall Type
Mortar rubble Quantity of high- High cost; relatively wide Applicable mainly to fill
masonry walls quality backfill base width, on the order situations where foundation
required is relatively of 60 to 70% of the wall conditions consist of very
small. height; cannot tolerate dense soil or rock; due
settlement. to expense, only used in
areas where other mortar
rubble masonry walls are
present and it is desired
to match aesthetics;
typically can be designed for
maximum heights of 25 feet.
Unreinforced Quantity of high- High cost; relatively wide Applicable mainly to fill
concrete gravity quality backfill base width, on the order situations where foundation
walls required is relatively of 60 to 70% of the wall conditions consist of very
small. height; cannot tolerate dense soil or rock; due
settlement. to expense, only used in
areas where other gravity
walls are present and it is
desired to match aesthetics;
typically can be designed for
maximum heights of 25 feet.
Reinforced concrete Relatively narrow High cost; cannot tolerate Applicable to cut and fill
cantilever walls base width on much settlement; relatively situations; can be routinely
the order of 50 to deep embedment might be designed for heights up
60% of the wall required on sloping ground to 35 feet.
height; can be used due to toe in front of face
to support structure wall.
foundations by
special design.
Reinforced concrete Relatively narrow High cost; cannot tolerate Applicable to cut and fill
counterfort walls base width on much settlement; relatively situations; can be routinely
the order of 50 deep embedment might be designed for heights up
to 60% of the wall required on sloping ground to 50 feet; proprietary
height; can be used due to toe in front of wall versions are typically 33 feet
to support structure face. maximum.
foundations by
special design.

Summary of Rigid Gravity and Semigravity Wall Options Available

Exhibit 730-3

WSDOT Design Manual M 22-01.05 Page 730-21

June 2009
Retaining Walls and Steep Reinforced Slopes Chapter 730

Specific
Advantages Disadvantages Limitations
Wall Type
Soldier pile wall Very narrow Relatively high cost. Applicable mainly to cut
base width; deep situations; maximum
embedment to get feasible exposed height
below potential is on the order of 10 feet;
failure surfaces; difficult to install in bouldery
relatively easy soil or soil with water-
to obtain. bearing sands.
Sheet pile wall Low to moderate Difficult to get embedment Applicable mainly to cut
cost; very narrow in dense or bouldery soils; situations in soil; maximum
base width. difficult to protect against feasible exposed height is
corrosion. on the order of 10 feet.
Cylinder pile wall Relatively narrow Very high cost. Applicable mainly to cut
base width; can situations; maximum
produce stable wall feasible exposed height is
even if deep on the order of 20 to 25 feet
potential failure depending on the passive
surfaces present. resistance available; can be
installed in bouldery
conditions, though cost will
increase.
Slurry wall Relatively narrow Very high cost; difficult Applicable mainly to cut
base width; can construction. situations; maximum
produce stable feasible exposed height is
wall even if deep on the order of 20 to 25 feet,
potential failure depending on passive
surfaces present. resistance available.

Summary of Nongravity Wall Options Available

Exhibit 730-4

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Chapter 730 Retaining Walls and Steep Reinforced Slopes

Specific
Advantages Disadvantages Limitations
Wall Type
All nongravity Relatively narrow Very high cost; difficult Applicable only to cut
cantilever walls with base width; can to install in areas where situations; can be designed
tiebacks produce stable vertical or lateral clearance for heights of 50 feet
wall even if deep is limited; easements may or more depending on the
potential failure be necessary; installation specifics of the structure of
surfaces present. activities may impact the wall.
adjacent traffic.
All nongravity Relatively narrow Moderate to high cost; Applicable to partial cut/
cantilever walls with base width; can access required behind wall fill situations; can be
deadman anchors produce stable wall to dig trench for deadman designed for wall heights
even if deep anchor; may impact traffic of approximately 16 feet.
potential failure during deadman installation;
surfaces present. easements may be
necessary.

Summary of Anchored Wall Options Available

Exhibit 730-5

Wall/Slope Specific
Advantages Disadvantages Limitations
Classification Wall Type
Rockeries Only variations Low cost; narrow Slope needs Applicable to both cut and
are in rock sizes base width on to be at least fill situations; maximum
used and overall the order of 30% marginally stable feasible height in a cut,
wall dimensions. of the wall height without rockery even for excellent soil
required. present; cannot conditions, is approx.
tolerate much 16 feet and 8 feet in fill
settlement. situations.
Reinforced Only variations Low cost; can Room required Best suited to sloping fill
slopes are in tolerate large between the right situations; maximum height
geosynthetic settlements; of way line and limited to 30 feet unless
products can adapt well the edge of the geosynthetic products are
used and in to sloping ground shoulder to install used in which long-term
erosion-control conditions a 1H:1V slope. product durability is well
techniques used to minimize defined. Certain products
on slope face. excavation can be used in critical
required; high- applications and for greater
quality fill is not slope heights on the order
a requirement. of 60 feet or more, but
consider need, landscaping
maintenance, and the reach
of available maintenance
equipment.

Other Wall/Slope Options Available

Exhibit 730-6

WSDOT Design Manual M 22-01.05 Page 730-23

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Retaining Walls and Steep Reinforced Slopes Chapter 730

Typical Mechanically Stabilized Earth Gravity Walls

Exhibit 730-7

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Chapter 730 Retaining Walls and Steep Reinforced Slopes

Typical Prefabricated Modular Gravity Walls

Exhibit 730-8

WSDOT Design Manual M 22-01.05 Page 730-25

June 2009
Retaining Walls and Steep Reinforced Slopes Chapter 730

Typical Rigid Gravity, Semigravity Cantilever,

Nongravity Cantilever, and Anchored Walls
Exhibit 730-9

Page 730-26 WSDOT Design Manual M 22-01.05

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Chapter 730 Retaining Walls and Steep Reinforced Slopes

Typical Rockery and Reinforced Slopes

Exhibit 730-10 Remove underline from “reinforcement” above

WSDOT Design Manual M 22-01.05 Page 730-27

June 2009
Retaining Walls and Steep Reinforced Slopes Chapter 730

MSE Wall Drainage Detail

Exhibit 730-11

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Chapter 730 Retaining Walls and Steep Reinforced Slopes

Retaining Walls With Traffic Barriers

Exhibit 730-12

WSDOT Design Manual M 22-01.05 Page 730-29

June 2009
Retaining Walls and Steep Reinforced Slopes Chapter 730

Design Process – Initiated by region, except by HQ Bridge Office for walls included in bridge preliminary plan.

Coordination with State Bridge and Structures Architect, HQ Bridge Office and
HQ Geotech Office to identify wall concepts and constraints (0.5 to 1 month)

See Exhibit
730-13b for
proprietary Region develops and submits wall profile, plan, and cross sections
(site data) with design request to RME
Yes

Standard wall
No (Std. Plan walls, gabions Yes
Proprietary up to 6 ft and rockeries
No up to 5 ft)
> 10 ft
Wall Ht ** 10 ft *
Wall type:
nonstandard
nonproprietary Gabions  6 ft
[2] walls [1] [1] Rockeries  5 ft

Submit wall site data to Submit wall site data

HQ Bridge Office with design request to Submit wall site data
Geotech Office with design request to
HQ Geotech Office

HQ Geotech Office
HQ Geotech Office
performs geotech performs geotech Geotech by region
design and design and Materials Lab [3]
recommends wall recommends wall (1.5 to 3 months)
alternatives as alternatives as
appropriate appropriate
(1.5 to 4.5 months)
(1.5 to 4.5 months)

Soil nail nongravity HQ Geotech Office Region evaluates

HQ Bridge Office cantilever, anchored, or performs geotech potential for alternative
coordinates with HQ other structural walls design and wall systems to be used
Geotech Office, State recommends wall and coordinates with [3]
Bridge and Structures alternatives as State Bridge and
Architect, and region for appropriate Structures Architect for
final wall selection Geosynthetic walls and (1.5 to 3 months) final wall selection ***
slopes, rockeries
(0.0 to 1.5 months)

HQ Bridge Office Region evaluates

develops wall potential alternative wall
systems and
preliminary plan coordinates with the
(1 to 2 months) State Bridge and No Standard
Structures Architect for wall selected
final wall selection ***
Yes
HQ Bridge Office
prepares PS&E [1] Geosynthetic walls, concrete block
walls, soil nail walls, rockeries > 5 ft Region prepares wall
(3 to 6 months) HQ Geotech Office and/ height, reinforced slopes, and other PS&E
or HQ Bridge Office nonstandard nonpreapproved walls if
provides plan details the desired wall type is uncertain.
and specials and region [2] All other nonstandard, nonproprietary
prepares PS&E walls.
(0.5 to 1 month) [3] See notes and legend in Exhibit 730-
13b.

Retaining Wall Design Process

Exhibit 730-4a

Retaining Wall Design Process

Exhibit 730-13a

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July 2013
Chapter 730 Retaining Walls and Steep Reinforced Slopes

Proprietary

Yes

No Yes
Preapproved

>10 ft < 10 ft *
Wall Ht.**
Submit wall site data
with design request to
HQ Bridge Office, with a Geotech by region Materials
Submit wall site data with
copy to the Geotech Office Lab (1.5 to 3 months)
and the State Bridge and design request to
Structures Architect Geotech Office

Region evaluates potential

Geotech Office performs alternative wall systems to be
geotech design and Geotech Office performs used and coordinates with the
recommends wall geotech design and State Bridge and Structures
alternatives Architect for the final wall
as appropriate recommends wall
alternatives as appropriate section ***
(1.5 to 3 months)
(1.5 to 3 months)

HQ Bridge Office evaluates Region contacts proprietary

potential alternative wall wall suppliers to confirm
systems to be used and interest in being included in
coordinates with the State PS&E
Bridge and Structures
Architect and the region
for final wall selection No Preapproved Yes
(0.8 to 1.5 months) *** wall selected
Region prepares wall PS&E
(generalized wall plans,
profiles, and X-sections; other
site-specific details; and
HQ Bridge Office special provisions)
contacts proprietary wall
suppliers to obtain detailed
wall design
(2 to 4 months)
HQ Bridge Office and HQ
Geotech Office review wall
shop plans on contract (1
HQ Bridge Office month)
prepares PS&E
(0.5 to 1 month)

Notes:
“HQ Bridge Office” refers to the WSDOT HQ Bridge and Structures Office.
“Geotech Office” refers to the WSDOT HQ Geotechnical Office.
“State Bridge and Structures Architect” refers to the Architecture Section, HQ Bridge and Structures Office.
Regarding time estimates:
 Assumes no major changes in the wall scope during design.
 Actual times may vary depending on complexity of project.
 Contact appropriate design offices for more accurate estimates of time.
Legend:
Region provides courtesy copy of geotechnical report to HQ Geotechnical Office.
*Assumes soft or unstable soil not present and wall does not support other structures.
**The preapproved maximum wall height is generally 33 feet. Some proprietary walls might be less. (Check with the
HQ Bridge and Structures Office.)
***If the final wall selected is a different type than assumed, go back through the design process to ensure that all the
steps have been taken.

Retaining Wall Design Process: Proprietary

Exhibit 730-13b

WSDOT Design Manual M 22-01.10 Page 730-31

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Retaining Walls and Steep Reinforced Slopes Chapter 730

Page 730-32 WSDOT Design Manual M 22-01.10

July 2013
Chapter 740 Noise Barriers
740.01 General
740.02 Design
740.03 Procedures
740.04 Documentation
740.05 References

740.01 General
The function of a noise barrier is to reduce traffic noise levels in adjoining areas. The noise
abatement decisions are made during the environmental stage of project development, which is
a highly interactive process. Before a noise barrier is designed, the Washington State
Department of Transportation (WSDOT) needs to be confident that there is significant need, a
cost-effective and environmentally acceptable noise barrier, a source of funds, and acceptance
by adjacent property owners, local governmental agencies, and the general public.

Preliminary design information that may be found in the noise report includes:
 Sources of noise.
 Noise receiver locations.
 Predicted level of noise reduction.
 Locations of existing and future noise ¬impacts along the project corridor.
 Barrier location and height recommendations based on what is feasible and
reasonable.

Design of a noise barrier project is the result of a team effort coordinated by the Project
Engineer.

This chapter addresses the factors that are considered when designing a noise barrier and the
associated procedures and documentation requirements.

740.02 Design
The two basic types of noise barriers are the earth berm and the noise wall. An earth berm can
be constructed to the full height required for noise abatement or to partial height in conjunction
with a noise wall to reach the required height. A noise wall can be made of concrete, masonry,
metal, wood, or other approved innovative products, and can be supported by spread, pile,
shaft, or trench footings.

Consideration of the noise report and the visual characteristics of adjacent land forms,
vegetation, and structural elements (such as buildings, bridges, and retaining walls) will
determine whether a proposed noise barrier might be berm, wall, or both.

An earth berm is the primary alternative if the visual and environmental quality of the corridor
will be preserved or enhanced and materials and right of way widths are available. (See the
Roadside Manual for criteria for determining whether a vegetated earth berm is appropriate.)

The region uses the noise report and other environmental documents (see the Environmental
Manual) to help determine the location, exposure conditions, length, and height of the
proposed noise barrier.

WSDOT Design Manual M 22-01.13 Page 740-1

July 2016
Noise Barriers Chapter 740

To design and locate a noise barrier of any kind, consider the following:
 Desired noise abatement
 Future right of way needs
 Cost and constructability
 Neighborhood character
 Visual character and quality of the corridor
 Future maintenance of the noise barrier and the whole right of way
 Wind
 Supporting soil
 Earthquakes
 Groundwater
 Existing drainage systems and water courses
 Exposure to vehicular impacts
 Potential for vandalism
 Existing vegetation and roadside restoration required
 Access for maintenance equipment and enforcement, traffic service, and emergency
vehicles
 Access to fire hydrants from both sides
 Pedestrian and bicycle access
 Available and attainable width of right of way for berms
 Aesthetic and structural characteristics of available wall designs
 Visual compatibility of each wall design with other transportation structures within the
corridor
 Construction limits for footings
 Locations of existing survey monuments
 Access to and maintenance of right of way behind a wall, including drainage structures
 Use of right of way and wall by adjacent property owners
 Drainage and highway runoff
 Drainage from adjacent land
 Existing utilities and objects to relocate or remove
 Water and electricity needs, sources, and access points

Avoid objects such as bridge columns, light fixtures, or sign supports that protrude and may
present a potential for snagging vehicles.

740.02(1) Earth Berm

Berm slopes are a function of the material used, the attainable right of way width, and the
desired visual quality. Slopes steeper than 2H:1V (3H:1V for mowing) are not recommended.
Design the end of the berm with a lead-in slope of 10H:1V and curve it toward the right of way
line.

Refer to the Roadside Manual for guidance regarding vegetation on berms.

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Chapter 740 Noise Barriers

740.02(2) Noise Wall

When feasible, to encourage competitive bidding, include several alternate noise wall designs in
the contract and permit the ¬contractor to submit alternate designs under the value
engineering specification.

There are noise wall designs in the Standard Plans. Additional designs are in various stages of
development to become standard plans. The draft-standard design sheets and other
preapproved plans are available from the Headquarters (HQ) Bridge and Structures Office. The
HQ Bridge and Structures Office also works with the regions to facilitate the use of other designs
as bidding options.

When a noise wall has ground elevations that are independent of the roadway elevations, a
survey of ground breaks (or cross sections at 25 foot intervals) along the entire length of the
wall is needed for evaluation of constructability and to assure accurate determination of panel
heights.

Size of openings (whether lapped, door, or gated) depends on the intended users. Agencies such
as the local fire department can provide the necessary requirements. Unless an appropriate
standard plan is available, such openings are designed and detailed for the project.

When a noise wall is inside the Design Clear Zone, design its horizontal and vertical (ground
elevation) alignment as if it were a rigid concrete traffic barrier. (See Chapter 1610 for maximum
flare rates.)

Provide a concrete traffic barrier shape at the base of a new noise wall constructed 12 feet or
less from the edge of the nearest traffic lane. The traffic barrier shape is optional at the base of
the new portion when an existing vertical-faced wall is being extended (or the existing wall may
be retrofitted for continuity). Standard Concrete Barrier Type 4 is recommended for both new
and existing walls except when the barrier face can be cast as an integral part of a new wall.
Design analyses may be considered, but they require approval as prescribed in Chapter 300.
A design analysis is not required where sidewalk exists in front of the wall or in other situations
where the wall face is otherwise inaccessible to traffic. For flare rates and approach slopes for
concrete barriers, see Chapter 1610, Traffic Barriers.

To designate a standard noise wall, select the appropriate general special provisions (GSPs) and
state the standard plan number, type, and foundation type.

Wall type is a function of exposure and wind speed (see Exhibit 740-1).

A geotechnical report identifying the angle of internal friction “f” and the allowable bearing
pressure is needed for selection of a standard foundation. The standard spread footing designs
require an allowable bearing pressure of 1 Tsf. The standard trench and shaft footing designs
require an “f” of at least 32° for D1 and 38° for D2.

A special design of the substructure is required for noise walls on substandard soil, where winds
exceed 90 mph, and for exposures other than B1 and B2 as defined in Exhibit 740-1.

For maintenance of the surface of a tall wall (10 feet or more), consider harness tie offs for the
fall protection required by the Department of Labor and Industries.

WSDOT Design Manual M 22-01.13 Page 740-3

July 2016
Noise Barriers Chapter 740

Exhibit 740-1 Standard Noise Wall Types

Exposure

B1 B2 C

Wind Speed 80 mph 90 mph 80 mph 90 mph

Wall Type A B C D Special Design *

Wind speed is according to Figure 1-2.1.2.A of the (AASHTO) Guide Specifications for Structural
Design of Sound Barriers. Assume the wind to be perpendicular to the wall on both sides and
design for the most exposed side.

Exposure is determined by the nature of the immediately adjacent ground surface and the
extension of a plane at the adjacent ground surface elevation for 1500 feet to either side of the
noise wall:

Exposure B1 = Urban and suburban areas with numerous closely spaced obstructions having
the size of single-family or larger dwellings that prevail in the upwind direction
from the noise barrier for a distance of at least 1,500 feet.

Exposure B2 = Urban and suburban areas with more open terrain not meeting the
requirements of Exposure B1.

Exposure C = Open terrain with scattered obstructions that includes flat, open country,
grasslands, and elevated terrain.

*For a noise wall with Exposure C, on a bridge or overpass or at the top of a slope, consult the
HQ Bridge and Structures Office, as a special design will probably be necessary.

740.03 Procedures
The noise unit notifies the Project Engineer’s Office when a noise barrier is recommended in the
noise report.

The Project Engineer’s Office is responsible for interdisciplinary teams, consultation, and
coordination with the public, noise specialists, maintenance, construction, region Landscape
Architecture Office (or the HQ Roadside and Site Development Section), right of way personnel,
Materials Laboratory, State Bridge and Structures Architect, HQ Bridge and Structures Office,
CAE Support Team, HQ Development Services & Access Manager, consultants, and many others.

If a noise wall is contemplated, the region evaluates the soils (see Chapters 610 and 710) and
obtains a list of acceptable wall design options. The list is obtained by sending information
pertaining to soils and drainage conditions, alignment, and height of the proposed wall to the
State Bridge and Structures Architect.

If a vegetated earth berm is considered, see the Roadside Manual for procedures.

The State Bridge and Structures Architect coordinates with the HQ Bridge and Structures Office,
HQ Hydraulics Section, HQ Geotechnical Office, and the region to provide a list of acceptable
standard, draft-standard, and preapproved proprietary noise wall designs, materials, and
finishes that are compatible with existing visual elements of the corridor. Only wall designs from

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July 2016
Chapter 740 Noise Barriers

this list may be considered as alternatives. Limit design visualizations of the highway side of
proposed walls (available from the CAE Support Team in Olympia) to options from this list. The
visual elements of the private property side of a wall are the responsibility of the region unless
addressed in the environmental documents.

After the noise report is completed, any changes to the ¬dimensions or location of a noise
barrier must be reviewed by the appropriate noise unit to determine the impacts of the changes
on noise abatement.

On limited access highways, coordinate any opening in a wall or fence (for pedestrians or
vehicles) with the HQ Development Services & Access Manager and obtain approval from the
Director & State Design Engineer, Development Division.

On nonlimited access highways, an access connection permit is required for any opening
(approach) in a wall or fence.

The HQ Bridge and Structures Office provides special substructure designs to the regions upon
request; reviews contract design data related to standard, draft-standard, and preapproved
designs; and reviews plans and calculations that have been prepared by others (see Chapter
710).

Approval by the State Bridge and Structures Architect is required for any attachment or
modification to a noise wall and for the design, appearance, and finish of door and gate-type
openings.

Approval by the State Bridge and Structures Architect is also required for the final selection of
noise wall appearance, finish, materials, and configuration.

740.04 Documentation
Refer to Chapter 300 for design documentation requirements.

740.05 References

740.05(1) Design Guidance

Guide Specifications for Structural Design of Sound Barriers, AASHTO, 2002

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

740.05(2) Supporting Information

Environmental Manual, M 31-11, WSDOT
Roadside Manual, M 25-30, WSDOT

WSDOT Design Manual M 22-01.13 Page 740-5

July 2016
Noise Barriers Chapter 740

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Chapter 800 Hydraulic Design
800.01 General
800.02 References
800.03 Hydraulic Considerations
800.04 Safety Considerations
800.05 Design Responsibility
800.06 Documentation

800.01 General
Hydraulic design factors can significantly influence the corridor, horizontal
alignment, grade, location of interchanges, and necessary appurtenances required
to convey water across, along, away from, or to a highway or highway facility.
An effective hydraulic design conveys water in the most economical, efficient,
and practical manner to ensure reasonable public safety without incurring excessive
maintenance costs or appreciably damaging the highway or highway facility, adjacent
property, or the total environment.
This chapter is intended to serve as a guide to highway designers so they can
identify and consider hydraulic-related factors that impact design. Detailed
criteria and methods that govern highway hydraulic design are in the Washington
State Department of Transportation (WSDOT) Hydraulics Manual and
Highway Runoff Manual.
Some drainage, flood, and water quality problems can be easily recognized and
resolved; others might require extensive investigation before a solution is developed.
Specialists experienced in hydrology and hydraulics can contribute substantially
to the planning and project definition phases of a highway project by recognizing
potentially troublesome locations, making investigations, and recommending
practical solutions. Regions may request that the Headquarters (HQ) Hydraulics
Section provide assistance regarding hydraulic problems.
Since hydraulic factors can affect the design of a proposed highway or highway
facility from its inception, consider these factors at the earliest possible time during
the planning phase.
In the project definition phase, begin coordination with all state and local
governments and Indian tribes that issue or approve permits for the project.

800.02 References
(1) Design Guidance
Highway Runoff Manual, M 31-16, WSDOT
Hydraulics Manual, M 23-03, WSDOT
Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans),
M 21-01, WSDOT
Standard Specifications for Road, Bridge, and Municipal Construction (Standard
Specifications), (Amendments and General Special Provisions), M 41-10, WSDOT
Utilities Manual, M 22-87, WSDOT

WSDOT Design Manual M 22.01.05 Page 800-1

June 2009
Hydraulic Design Chapter 800

(2) Special Criteria

Special criteria for unique projects are available by request from the HQ
Hydraulics Section.

800.03 Hydraulic Considerations

(1) The Flood Plain
Encroachment of a highway or highway facility into a flood plain might present
significant problems. A thorough investigation includes the following:
• The effect of the design flood on the highway or highway facility and the
required protective measures.
• The effect of the highway or highway facility on the upstream and downstream
reaches of the stream and the adjacent property.
• Compliance with hydraulic-related environmental concerns and hydraulic
aspects of permits from other governmental agencies per Chapters 225220 and
230..
Studies and reports published by the Federal Emergency Management Agency
(FEMA) and the U.S. Army Corps of Engineers are very useful for flood plain
analyses. The HQ Hydraulics Section has access to all available reports and can
provide any necessary information to the region.

(2) Stream Crossings

When rivers, streams, or surface waters (wetland) are crossed with bridges or
culverts (including open-bottom arches and three-sided box culverts), consider:
• Locating the crossing where the stream is most stable.
• Effectively conveying the design flow(s) at the crossing.
• Providing for passage of material transported by the stream.
• The effects of backwater on adjacent property.
• Avoiding large skews at the crossing.
• The effects on the channel and embankment stability upstream
and downstream from the crossing.
• Location of confluences with other streams or rivers.
• Fish and wildlife migration.
• Minimizing disturbance to the original streambed.
• Minimizing wetland impact.
For further design details, see the Hydraulics Manual.

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Chapter 800 Hydraulic Design

(3) Channel Changes

It is generally desirable to minimize the use of channel changes because ongoing
liability and negative environmental impacts might result. Channel changes are
permissible when the designer determines that a reasonable, practicable alternative
does not exist. Consult the HQ Hydraulics Section for the best guidance when
channel changes are considered.
When channel changes are used, consider the following:
(a) Restoration of the original stream characteristics as nearly as practicable.
This includes:
• Meandering the channel change to retain its sinuosity.
• Maintaining existing stream slope and geometry (including meanders)
so stream velocity and aesthetics do not change in undisturbed areas.
• Excavation, selection, and placement of bed material to promote formation
of a natural pattern and prevent bed erosion.
• Retention of streambank slopes.
• Retention or replacement of streamside vegetation.
(b) The ability to pass the design flood.

(c) The effects on adjacent property.

(d) The effects on the channel and embankment upstream and downstream from
the channel change.

(e) Erosion protection for the channel change.

(f) Environmental requirements such as wetlands, fish migration, and vegetation
reestablishment.

(g) The drainage pattern. Do not redirect flow from one drainage basin to another;
follow the historical drainage pattern.

(4) Roadway Drainage

Effective collection and conveyance of stormwater is critical. Incorporate the
most efficient collection and conveyance system considering initial highway
costs, maintenance costs, and legal and environmental considerations.
Of particular concern are:
• Combinations of vertical grade and transverse roadway slopes that might
inhibit drainage.
• Plugging of drains on bridges as the result of construction projects. This creates
maintenance problems and might cause ponding on the structure. The use
of drains on structures can be minimized by placing sag vertical curves and
crossovers in superelevation outside the limits of the structure.
For discussion of the relationship of roadway profiles to drainage profiles, see
Chapter 1220.

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June 2009
Hydraulic Design Chapter 800

(5) Subsurface Drainage

Subsurface drainage installations control groundwater encountered at highway
locations. Groundwater, as distinguished from capillary water, is free water occurring
in a zone of saturation below the ground surface. The subsurface discharge depends
on the effective hydraulic head and on the permeability, depth, slope, thickness, and
extent of the aquifer.
The solution of subsurface drainage problems often calls for specialized knowledge
of geology and the application of soil mechanics. The Region Materials Engineer
evaluates the subsurface conditions and includes findings and recommendations
for design in the geotechnical report.
Typical subdrain installations control seepage in cuts or hillsides, control base and
shallow subgrade drainage, or lower the groundwater table (in swampy areas, for
example).
Design a system that will keep the stormwater out of the subsurface system when
stormwater and subsurface drainage systems are combined.

(6) Subsurface Discharge of Highway Drainage

Consider subsurface discharge of highway drainage when it is a requirement of the
local government or when existing ground conditions are favorable for this type of
discharge system. Criteria for the design of drywells or subsurface drainage pipe for
this type of application are described in the Hydraulics Manual. The criteria for the
design of infiltration ponds are described in the Highway Runoff Manual.

(7) Treatment of Runoff

On certain projects, effective quantity control of runoff rates and removal of
pollutants from pavement are intended to address flooding and water quality impacts
downstream. (See the Highway Runoff Manual for specific criteria on quantity and
quality control of runoff.)

800.04 Safety Considerations

Locate culvert ends outside the Design Clear Zone when feasible. (See Chapter 1600
for culvert end treatments when this is infeasible.)
For detention ponds and wetland mitigation sites, see Chapter 560 regarding fencing.

800.05 Design Responsibility

The Hydraulics Manual describes the responsibilities of the regions and the HQ
Hydraulics Section regarding hydraulic design issues.

800.06 Documentation
For the list of documents required to be preserved in the Design Documentation
Package and the Project File, see the Design Documentation Checklist:
 www.wsdot.wa.gov/design/projectdev

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June 2009
Chapter 900 Roadsides
900.01 General
900.02 Project Development
900.03 Documentation
900.04 References

900.01 General
The Washington State Department of Transportation (WSDOT) recognizes roadsides as an asset.
WSDOT is committed to highway designs that meet the transportation needs in a way that
reduces the potential for fatal and injury crashes, is cost-effective, ecologically appropriate,
context appropriate, and maintainable by managing roadsides that balance the natural and
environmental functions within the right of way.

The roadside integrates natural processes and visual continuity into the built (roadway)
environment, preserving and promoting these natural and environmental functions. Highway
projects achieve this integration through introduction and configuration of specific design
elements such as structures, vegetation, signs, pedestrian and bicycle movement, erosion
control, stormwater treatment facilities, etc.

Develop highway designs in accordance with the criteria provided in the current version of
WSDOT Roadside Policy Manual (RPM). Use guidance provided in the WSDOT Roadside Manual
(RM), where appropriate, when implementing the provisions of the RPM. Provide coordination
and engagement with WSDOT partners when designing roadsides. Also refer to the RM when
addressing design issues such as law and policy, soil bioengineering, contour grading,
vegetation, irrigation, etc. These manuals can be found at:
www.wsdot.wa.gov/design/roadside/.

900.02 Project Development

900.02(1) Region Landscape Architect
The region Landscape Architect is responsible for the following:
Designs, supervises, has approval authority over, and stamps plans for wetland
mitigation, roadside restoration, and revegetation.
Coordinates the visual elements within highway corridors, in conjunction with the
State Bridge and Structures Architect.
Designs and supervises other roadside work, such as site design for park & ride lots
or safety rest areas, to ensure roadside restoration is designed and constructed to
WSDOT guidelines and standards.
Provides visual discipline reports for environmental documentation.
Assists the region in completing the plant establishment phase of projects.

The Headquarters (HQ) Roadside and Site Development Section will provide roadside and
mitigation design, visual impact assessment, and construction inspection work for the project
offices in regions without a Landscape Architect. Refer to the Project Management Online Guide
for further descriptions of the roles and responsibilities of project teams.
WSDOT Design Manual M 22-01.17 Page 900-1
September 2019
Roadsides Chapter 900

900.02(2) Roadside Restoration Projects

There are typically two types of roadside restoration projects pertaining to vegetation-related
roadway construction projects: regulatory and restoration.

900.02(2)(a) Regulatory
The first type of project is work related to regulatory or permit requirements. Examples are
wetland mitigation work or Hydraulic Permit Approvals (HPAs). This work typically must occur
by the time the impacting project is complete.

900.02(2)(b) Restoration
The second type of project is the restoration of construction impacts to roadside functions to
meet the WSDOT policy requirements outlined in the Roadside Policy Manual.

900.02(3) Stand-Alone Project or Part of Roadway Construction?

Roadside restoration work should be evaluated by the design team to determine whether it will
be most efficient as part of the roadway construction contract or as a separate stage contract.

900.02(3)(a) Roadway Construction Contract

The benefits of roadside restoration during roadway construction include the following:
All work can be done under one contract.
The restoration can be completed without waiting for a new contract to be let
and administered.
Plant establishment can often begin sooner.

900.02(3)(b) Separate Stage Project

A separate stage contract provides the following opportunities because it would be done when
road construction is completed:
If construction impacts are different than originally anticipated, the restoration
contract can be changed. For example, if disturbance is minimized, fewer plants and
soil amendments may be needed.
The site can be watched to see how the grading and hydrology interact before plants
are planted.
The prime contractor can be someone who specializes in roadside work.

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September 2019
Chapter 900 Roadsides

900.02(4) Plant Establishment

Plant establishment periods are included as part of roadside restoration and on all
environmental mitigation projects.
A minimum of three years of plant establishment work is required for all planted
areas in western Washington, and planted and/or seeded areas in eastern
Washington.
In situations where it is important to provide a full cover of vegetation to achieve
the environmental or operational functions, five years of plant establishment may
be needed.
If the plant establishment period will last longer than three years on a roadside
restoration contract, discussion should occur with Program Management to request
and justify additional funding.
In an environment that uses woody plants, plant establishment may take up to
10 years for the woody vegetation to exclude weeds and reach a condition with
the lowest life cycle cost.
Regulatory aspects of projects can require 10 years of plant establishment to ensure
the standards of success outlined in the permit, although aggressive weed control
and favorable weather can allow sites to close out early.

The goal is to give WSDOT Maintenance a site that is nearly self-sustaining after the plant
establishment period is complete.

900.03 Documentation
Refer to Chapter 300 for design documentation requirements.

900.04 References
Maintenance Manual, M 51-01, WSDOT
Roadside Manual, M 25-30, WSDOT
Roadside Policy Manual, M 3110, WSDOT
Understanding Flexibility in Transportation Design – Washington, WSDOT, 2004
Utilities Accommodation Policy, M 22-86, WSDOT
For utility-related roadside issues, see the Utilities Manual, and for Scenic Classification ratings,
see the Utilities Accommodation Policy
For WSDOT Project Management web resources, start here:
 www.wsdot.wa.gov/projects/projectmgmt/
Roadside Design Guide, AASHTO, 2011
Roadside development concepts covered elsewhere in the Design Manual include the following:
Fencing (Chapter 560)
Jurisdiction (Chapters 300, 1100, 1600)
Noise barriers (Chapter 740)
Pedestrian facilities (Chapter 1510)
WSDOT Design Manual M 22-01.17 Page 900-3
September 2019
Roadsides Chapter 900

Public art (Chapter 950)

Retaining walls (Chapter 730)
Roadside safety, traffic barriers, and energy attenuators (Chapters 1600, 1610, 1620)
Safety rest areas, parks, viewpoints, and historical markers (Chapter 1710)
Signs (Chapter 1020)

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September 2019
Chapter 950 Public Art
950.01 General
950.02 References
950.03 Standard Architectural Design
950.04 Criteria for Public Art
950.05 Process and Project Delivery Timing
950.06 Approvals
950.07 Documentation

950.01 General
There has been a growing interest on the part of communities What is public art?
to use art within the transportation facilities of the Washington
State Department of Transportation (WSDOT). It can be used For the purposes of WSDOT
to provide visual interest along roadsides, make unique policy, public art is an
statements about community character, and create a positive enhancement to a functional
public response that will last over time. element, feature, or place
within a transportation
Proponents for public art might be local agencies or engaged corridor to provide visual
citizens’ groups with interest in the outcome of a WSDOT interest. The enhancement
project. The environmental and public involvement processes could be an addition to a
offer opportunities for community partnership on the visual functional element,
and aesthetic qualities of a corridor. integrated into a design,
or for purely aesthetic
The public art policy in this chapter is intended to: provide
purposes.
guidance for managing public art on WSDOT facilities and
within its rights of way; reinforce the existing policy in the An element is considered
Roadside Policy Manual; designate appropriate locations for “public art” if it is beyond
the incorporation of public art features; and provide for the WSDOT standard practice
consistent use of statewide development, review, and approval for architectural treatment.
processes on new and existing features.

The appropriateness of public art is frequently dependent upon its location and composition.
For example, an art piece or feature chosen for the back side of a noise wall, at a safety rest
area, or along a bike path may not be suitable at the end of a freeway ramp or along the main
line of a highway. In addition to appropriate placement, WSDOT must balance the requests for
proposed public art projects with the need to provide corridor continuity, improve the unity of
highway elements, and provide roadsides that do not divert motorists’ attention from driving.

While some local jurisdictions dedicate a percentage of their project budgets for art, WSDOT
has no such dedicated funding. Section 40 of the State Constitution specifies that gas tax money
must be used for a “highway purpose.” Therefore, public art beyond WSDOT standard design
is typically funded by communities or other entities outside of WSDOT.

When city or community entrance markers are proposed, this policy should be used in
conjunction with the guidance contained in Chapter 1600, Roadside Safety, the Traffic Manual,
and the Roadside Policy Manual.

WSDOT Design Manual M 22-01.11 Page 950-1

July 2014
Public Art Chapter 950

950.02 References
950.02(1) Federal/State Laws and Codes
Chapter 47.42 Revised Code of Washington (RCW), Highway advertising control act –
Scenic vistas act

950.02(2) Design Guidance

Bridge Design Manual, M 23-50, WSDOT
Roadside Policy Manual, M 25-31, WSDOT

950.02(3) Supporting Information

A Guide for Achieving Flexibility in Highway Design, AASHTO, 2004
Flexibility in Highway Design, FHWA, 1997
Roadside Manual, M 25-30, WSDOT
Traffic Manual, M 51-02, WSDOT
Understanding Flexibility in Transportation Design – Washington, WSDOT, 2005
 www.wsdot.wa.gov/research/reports/600/638.1.htm

950.03 Standard Architectural Design

WSDOT’s public art policy does not apply to the standard design of transportation architectural
elements such as simple geometric patterns; combinations of WSDOT standard concrete
formliners; contrasting pavement patterns or colors in crosswalks or roundabouts; or earth-
tone colors on structures or barriers.

To discuss the details of proposed public art projects, contact the State Bridge and Structures
Architect, and the region or Headquarters (HQ) Landscape Architect for regions without a
Landscape Architect. They are key members of the Public Art Specialty Services Team (described
in 950.05) and can answer questions and assist in determining an appropriate course of action.

950.04 Criteria for Public Art

Placement and composition of public art is unique and is to be evaluated on a case-by-case
basis. Prior to approval of public art, a public art plan is to be developed in coordination with
the Public Art Specialty Services Team. The team will review the concept, guide the local agency
or design team through the process, and approve the plan in accordance with 950.06.

The following criteria are to be addressed and documented in the public art plan:
• The public art proponent, the funding source, and those responsible for the installation
and maintenance of the proposed art.
• Safe maintenance access.
• Maintenance Agreement with local agencies for maintenance where appropriate. If
there is a potential for vandalism, address this issue in the associated maintenance
agreement.

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Chapter 950 Public Art

• Whether public art resulted from the specific recommendation(s) of a planning-level

study.
• Subject of the recommended art.
• Visibility:
o Art visible from the main line must contribute to corridor continuity and the
view from the road.
o Art visible to the community or adjacent to the neighborhood side of a structure
may have more flexibility in design than that visible from the main line.
• Safety and security: Public art must not negatively impact safety nor create an
attractive nuisance.
• Potential for traffic distraction: Proposed art must not distract motorists. It must be
appropriate for the speed and angle at which it will be viewed.
• Scale and context: The public art plan should address the scale of the proposed work
and its fit within the surrounding landscape and land use.
• Contribution of the art to community character.
• Impact of the proposed art on social, cultural, and environmental features:
o In general, WSDOT would not approve the addition of art on a historic
structure or within an ecologically sensitive area.
• Compliance with applicable laws, such as the Scenic Vistas Act and 23 CFR 752,
Landscape and Roadside Development.
• Compliance with the Traffic Manual and the Roadside Policy Manual:
o Lettering that can be construed as advertisement is not allowed.
o “Welcome to [insert city name]” lettering is permissible at the end of ramps
if it complies with the Traffic Manual section on Sign Design.
o Locations for community gateway signs are described in the Roadside Policy
Manual.
• Demonstrated responsible use of tax dollars and enhanced public trust in WSDOT
judgment.

For further information on these criteria, see the Roadside Manual.

950.04(1) Acceptable Public Art Features

Public art must be in compliance with WSDOT corridor guidelines, such as the Mountains to
Sound Greenway Implementation Plan or the I-90 Architectural Design Standards, and existing
policies such as the Roadside Policy Manual and the Bridge Design Manual.

WSDOT Design Manual M 22-01.11 Page 950-3

July 2014
Public Art Chapter 950

The following are examples of types and locations of acceptable public art features:
• Concrete surface treatments (beyond WSDOT standard)
• Colored paving/colored pavers/scoring patterns (beyond WSDOT standard)
• Specially designed benches, trash cans, planters, or other street furnishings
• Soft lighting and lighting fixtures
• Small-scale sculptures or art pieces (when not viewed from the main line)
• Attachments to decorative railings, light poles, or fences
• Decorative bus shelters

950.04(2) Unacceptable Public Art Features

The following are examples of unacceptable public art features:
• Kinetic sculptures
• Brightly lit or flashing art
• Art that poses a safety risk or liability
• Large sculptures (the size is relative to its context and location in the landscape)
• Art with highly reflective qualities or adverse colors
• Art that is a distraction to drivers or out of context with the surroundings
• Art with a topic/theme that could cause negative public reaction
• Art that resembles a traffic control device
• Art that contains advertising

950.05 Process and Project Delivery Timing

Begin the development and review of public art early in the design process, and conduct
subsequent reviews during the course of its development. Do not include public art as a change
order or addendum to a project without first having gone through the process described in this
policy. Project Ad and Award dates will not be delayed due to an incomplete public art process.

A public art plan is developed to incorporate public art into projects on state highways. Include
the review of the public art plan by the Public Art Specialty Services Team in project reviews.

950.05(1) Public Art Plan

The public art plan is developed by the Project Engineer’s Office or by the local artist or
community sponsoring the proposal. The plan provides enough detail and description to convey
the intent of the proposed art project. The plan documents how the proposed art meets the
criteria listed in 950.04 and includes the following elements:
• Cover sheet with appropriate approval signatures (see 950.06).
• Project overview.

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Chapter 950 Public Art

• Location of the proposed art.

• Scale drawings of the proposed art, including proposed materials, attachments, and
finishes. Any attachments to fencing or structures, or proposed new structures, will
require structural engineering calculations.
• All criteria from 950.04, Criteria for Public Art, addressed and documented.
• Justification and recommendations for public art.
• Documentation showing support by the local community.

Without an approved public art plan, a Maintenance Agreement (as appropriate), and funding,
the “art” will not be constructed or installed.

950.05(2) Public Art Specialty Services Team

Include the Public Art Specialty Services Team in the development of public art and the public
art plan. The Team includes the following:
• Project Engineer or a designee (if the art is included in a project)
• State Bridge and Structures Architect
• Region or HQ Landscape Architect
• Region Traffic Engineer
• Region Local Programs Engineer (if the proponent is a local community)

For public art proposed within Interstate Limited Access, the following team members are also
required:
• Assistant State Design Engineer
• Federal Highway Administration (FHWA) Safety/Geometric Engineer or a designee

Consider team membership from the following functional areas when their expertise is
applicable:
• Maintenance
• Planning
• Environmental
• Real Estate Services

950.06 Approvals
950.06(1) Intermediate Approvals
The Public Art Specialty Services Team is responsible for approving the public art; therefore,
be sure to involve them in the development of art during the earliest possible phase of project
development. This will ensure approvals happen smoothly and WSDOT and FHWA are aware
of the public art as soon as possible.

WSDOT Design Manual M 22-01.11 Page 950-5

July 2014
Public Art Chapter 950

Project development phases include the following:

• Initial Art Concept review: input and approval.
• Selected Art Concept review: input and approval.
• Final Proposed Art review: input and approval.

950.06(2) Final Approval

Approval of the public art plan is considered approval for the public art. The public art plan
cover letter needs to include the following approval signatures as appropriate.
950.06(2)(a) Within Limited Access

Public art within Limited Access on the Interstate is approved by:

 Project Engineer or a designee (if the art is included in a project)
 State Bridge and Structures Architect
 Region or HQ Landscape Architect
 Region Traffic Engineer
 Region Local Programs Engineer (if the proponent is a local community)
 Assistant State Design Engineer
 Region Administrator or designee
 FHWA Safety/Geometric Design Engineer or designee

950.06(2)(b) All Other Projects

Public art for all other projects is approved by:

 Project Engineer or a designee (if the art is included in a project)
 Region or HQ Landscape Architect
 State Bridge and Structures Architect
 Region Traffic Engineer
 Region Local Programs Engineer (if the proponent is a local community)
 Region Administrator or designee

950.07 Documentation
The public art plan, complete with approval signatures, is retained in the Design Documentation
Package (DDP).

Refer to Chapter 300 for design documentation requirements.

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July 2014
Chapter 1010 Work Zone Safety and Mobility
1010.01 General
1010.02 Definitions
1010.03 Work Zone Safety and Mobility
1010.04 Transportation Management Plans and Significant Projects
1010.05 Developing TMP Strategies
1010.06 Work Zone Capacity Analysis
1010.07 Work Zone Design
1010.08 Temporary Traffic Control Devices
1010.09 Positive Protection Devices
1010.10 Other Traffic Control Devices or Features
1010.11 Traffic Control Plan Development and PS&E
1010.12 Training and Resources
1010.13 Documentation
1010.14 References

1010.01 General
Addressing work zone impacts to all road users is an important component in the design of a
project and needs to be given adequate consideration early in the design process. Most work
zones create some level of traffic impacts and require additional safety features; therefore,
all work areas and operations needed for construction must be identified and addressed
during the project design. Planners, designers, construction engineers, maintenance
personnel, and others all play a role in developing a comprehensive work zone design.
Consider including Rail, Freight, and Ports, Commercial Vehicle Services, and Public
Transportation Divisions for help coordinating with freight and transit industries. See the
WSDOT Project Management website for information on project teams.
This chapter provides the designer with guidance to develop comprehensive work zone
strategies and plans to address a project’s safety and mobility benefits/improvements for all
modes, as well as constructability. A systematic process for addressing work zone impacts is
required by federal regulations and state policy.

1010.02 Definitions
The following terms are defined in the Design Manual Glossary:
 Transportation Management Area (TMA)
 Transportation Management Plan (TMP)
 work zone
 work zone impact
 work zone traffic control
 traveling public

WSDOT Design Manual M 22-01.18 Page 1010-1

December 2019
Work Zone Safety and Mobility Chapter 1010

1010.03 Work Zone Safety and Mobility

Washington State Department of Transportation (WSDOT) policy per Executive Order E 1001,
Work Zone Safety and Mobility, is intended to support systematic consideration and
management of work zone impacts across all stages of project development.
The policy states:

All WSDOT employees are directed to make the safety of workers and the
traveling public our highest priority during roadway design, construction,
maintenance, and related activities.

Designers should be familiar with this document. The policy defines how WSDOT programs
address work zone safety and mobility issues during project planning, design, and
construction.

1010.04 Transportation Management Plans and Significant Projects

1010.04(1) Transportation Management Plan

A transportation management plan is a set of strategies for managing the corridor-wide work
zone impacts of a project. A TMP is required for all projects and is the key element in
addressing all work zone safety and mobility impacts. The TMP development begins in the
scoping phase of a project by assessing impacts known at the time and then selecting
mitigating strategies and design solutions to manage those impacts. It is very important to
continue the development of the TMP throughout the project development process.
Not all work zone impacts have to be addressed with traffic control plans only. Many work
zone impacts can be reduced or eliminated through project design elements like alignment
choice, materials selection, structure types, overbuilding, and phased construction. Work
zone impacts related to work duration may be resolved or reduced through innovative
bidding and contract administration.
The three major components of a TMP are described below.

1010.04(1)(a) Temporary Traffic Control

Temporary Traffic Control (TTC) components are those strategies for directing traffic through
the work zone and minimizing the duration of the impacts. These components are to be
included in the Plans, Specifications, and Estimates (PS&E) as Traffic Control Plans (TCPs) and
contract provisions. The TTC components may include but are not limited to the following
strategies:
• TTC strategies such as lane closures or shifts, one-lane two-way operations (flagging and
or pilot car), staged construction, or full road closures and detours.
• Traffic Control Devices such as temporary signing, channelizing devices (cones, drums),
changeable message signs, arrow boards, temporary signals, and temporary pavement
markings.

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• Corridor Project Coordination, Contracting Strategies, and Innovative Construction

Strategies such as A+B bidding, incentives/disincentives, and precast members or rapid
cure materials.

1010.04(1)(b) Transportation Operations (TO)

The TO components are those strategies for improving traffic flow and safety through the
work zone. Some of these strategies may be included in the PS&E, but could also be WSDOT-
managed elements outside the contract. The TO components may include but are not limited
to the following strategies:
• Demand Management Strategies such as Transit service improvements, transit
incentives, and park & ride promotion.
• Corridor/Network Management (traffic operations) Strategies such as Signal
timing/coordination improvements, temporary signals, bus pullouts, reversible
lanes, and truck/heavy-vehicle restrictions.
• Work Zone Safety Management Strategies such as using positive protective devices,
speed limit reductions, automated flagger assistance devices, radar speed display
signs, and smart work zone systems.
• Traffic/Incident Management and Enforcement Strategies such as Work Zone
Intelligent Transportation Systems (ITS), Washington State Patrol, tow service,
WSDOT Incident Response Team vehicle(s), traffic screens, and emergency pullouts
in long work zones with narrowed shoulders.

1010.04(1)(c) Public Information (PI)

The PI components are those strategies for raising awareness of the upcoming project
impacts or current restrictions. Public awareness strategies may be developed and
implemented by WSDOT through the region or Headquarters (HQ) Communications offices
and implemented before and during construction. Motorist information strategies may be
WSDOT-managed elements with state equipment outside the contract or identified on plans
in the PS&E. The PI components may include, but are not limited to, the following strategies:
• Public Awareness Strategies such as Brochures or mailers, press releases, paid
advertisements, and project website (consider providing information in other languages
if appropriate).
• Motorist Information Strategies such as Highway advisory radio (HAR), changeable
message signs, and transportation management center (TMC).
It is very important to continue the development of the TMP throughout the project
development process. Not all work zone impacts have to be addressed with traffic control
plans only. Many work zone impacts can be reduced or eliminated through project design
elements like alignment choice, materials selection, structure types, overbuilding, and
phased construction. Work zone impacts related to work duration may be resolved or
reduced through innovative bidding and contract administration.

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The TMP Checklist in Exhibit 1010-3 will help identify and organize TMP components. Include
the completed checklist in the Project File. For significant projects, develop this checklist and
the supporting plans, data, impacts assessment, strategies, capacity/delay analysis and
endorsements into a formal TMP document to be included in the Project File. For TMP
examples, see:
 http://www.ops.fhwa.dot.gov/wz/resources/final_rule/tmp_examples/sample_tmps.htm
 http://www.ops.fhwa.dot.gov/wz/resources/publications/trans_mgmt_plans/trans_mgmt
_plans.pdf

1010.04(2) Significant Projects

The FHWA definition of a “significant project” is as follows:
A significant project is one that, alone or in combination with other concurrent
projects nearby, is anticipated to cause sustained work zone impacts that are
greater than what is considered tolerable based on state policy and/or
engineering judgment.
All Interstate system projects within the boundaries of a designated
Transportation Management Area (TMA) that occupy a location for more than
three days with either intermittent or continuous lane closures shall be
considered as significant projects.
Note: Significant projects require a TMP document addressing safety and mobility impacts
with strategies or elements from all three TMP components.
The size and scale of the TMP document will depend on the project’s complexity and
impacts. For examples of WSDOT TMP’s see:
 http://www.wsdot.wa.gov/Safety/WorkZones/resources.htm
For projects not identified as significant, the Temporary Traffic Control components included
in the PS&E will be considered the TMP. Transportation Operations and Public Information
components may also be required to properly address the impacts as many projects can have
significant work zone safety and mobility impacts, but are not necessarily a significant project
as defined under the federal requirements stated above. Consider developing a TMP
document for these types of projects as well.
The Project Summary must include a Work Zone Strategy Statement and indicate whether
the project is significant in regard to work zone impacts.
Significant projects may require a Value Engineering (VE) study (see Chapter 310) and a Cost
Risk Assessment (CRA) or Cost Estimate Validation Process (CEVP) that could help define
strategies or identify risks:  www.wsdot.wa.gov/projects/projectmgmt/riskassessment/

1010.05 Developing TMP Strategies

1010.05(1) Key Considerations

The following list is intended to alert the designer to actions and issues that need to be
addressed as part of a TMP. Addressing these items is required per WSDOT’s work zone

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policy and federal regulations, and they are key to the successful development of a project’s
TMP.
• Determine work zone impacts through an impact assessment process.
• Minimize, mitigate, and manage work zone impacts.
• Integrate work zone impacts strategies early, during planning, programming, and
design.
• Develop an accurate scoping estimate based on the work zone strategies.
• Hold a Work Zone Design Strategy Conference early in the design process. (Include
bridge, construction, traffic, maintenance, freight, transit, local agency, and law
enforcement personnel.)
• Utilize the Work Zone TMP Checklist/TMP document (required for significant projects).
• Emphasize flagger safety.
• Assess work zone mobility through a capacity analysis.
• Integrate project constructability, work efficiency and cost containment into the work
zone strategy.
• Attend work zone training.
• Address Washington State traffic and safety regulations as provided for by state law.
• Use the legally adopted Manual on Uniform Traffic Control Devices (MUTCD), with
Washington State modifications as the minimum standard.
• Provide an appropriate level of traffic control plans (TCPs).
• Consider work zone ITS elements.
• Use established design criteria in work zone roadway and roadside design.
• Accommodate pedestrian access (including ADA requirements) and maintenance of
existing transit stops and bicycle traffic.
• Consider maintenance issues and needs through the duration of the project.
• Consider school, hospital, emergency services, and postal delivery, impacts.
• Consider economic impacts (business access) due to traffic delay or restricted access.
• Consider freight mobility; total roadway widths to less than 16 feet should be avoided if
possible. Truck routes can be found here:
 http://www.wsdot.wa.gov/Freight/EconCorridors.htm
• Address traffic impacts extending beyond the project limits and impacting other roads.
• Identify seasonal or special event impacts that affect recreation or business due to work
zone impacts.
• Consider risk management and tort liability exposure.
• Approach the work zone design from the road user’s perspective.
• Incorporate worker safety needs (positive protection) in your work zone designs.
• Account for all needed work areas, operations and possible staging areas.
• Address work vehicle ingress and egress to each work area.
• Use of law enforcement

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1010.05(2) Impacts Assessment

One of the most important tasks in developing a TMP is assessing all of the project impacts to
mobility and safety. Impacts that are not identified and addressed in the TMP will
undoubtedly become issues during the construction phase of the project. A designer needs
to possess a clear understanding of how project features will be constructed, including work
methods, equipment, materials, and duration, to complete the work. Involve the
construction PE when making decisions on assessing and addressing impacts.

A complete and accurate impacts assessment will allow for the development of an effective
TMP that should only need minor modifications to address construction issues. The Traffic
Manual provides information on how to determine expected work zone congestion along
with mobility management strategies.

An early and ongoing impacts assessment allows time to:

• Develop TTC, TO, and PI (see Section 1010.04(1)) strategies to address identified
impacts as needed to effectively manage the project.
• Resolve potential work zone impacts within the design features of the project.
Decisions that consider work zone impacts during bridge type selection, materials
selection, advertisement dates, and others have the potential to resolve or
minimize work zone impacts.
• Consider innovative mitigation strategies that may involve many stakeholders.
Some impacts may be difficult to completely solve and may ultimately need a management
decision to determine the level of mitigation or impact that is acceptable. These types of
impacts need to be clearly addressed in the TMP with documentation supporting and
explaining the decision.
The following are some examples of impacts that need to be managed during the design of a
project:
1. Bridge construction sequence or falsework opening plans need to match the TTC staging
or channelization plans. Coordination with the HQ Bridge and Structures Office is
essential as the bridge design schedule may differ than the project schedule. Maintain
the legal height of 16 feet 6 inches as the minimum falsework opening whenever
possible; anything less than this must consider overheight vehicle impacts, possible
additional signing needs, and temporary bypass routes. Impacts to shoulder widths due
to barrier or bridge staging may impact bicycle or pedestrian access and must be
addressed in TTC plans. Refer to Chapter 720 for additional requirements and approvals.
Coordination with the Permits Office may be needed.
2. If existing signal and illumination systems are not able to be maintained during the
construction phases, plans for temporary systems or connections need to be included in
the project.
3. Temporary relocation of existing signing (including overhead signing) may be required
and should be detailed in the plans.
4. Permanent traffic loop installation (such as advance loops, turn pockets, and stop bars,
and ITS loops) and pavement marking installations (crosswalks, arrows, and so on) may
require specific TTC plans.

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5. What type of temporary marking is most appropriate for the installation, work duration,
and the pavement surface? Will the final pavement surface have a “ghost stripe”
potential?
6. Lane shifts onto existing shoulders:
• Is the depth of the existing shoulder adequate to carry the extra traffic and are
there rumble stripe that need to be removed?
• Are there any existing catch basins or junction boxes located in the shoulder that
cannot accept traffic loads over them?
• What is the existing side slope rate? If steeper than 4H:1V, does it need mitigation?
Are there existing roadside objects that, when the roadway is shifted, are now
within the clear zone limits?
• Shifting of more than one lane in a direction is only allowed with temporary
pavement markings. Shifting lanes by using channelizing devices is not allowed due
to the high probability that devices used to separate the traffic will be displaced.
• Signal head alignment: When the lane is shifted approaching the intersection, is the
signal head alignment within appropriate limits?
7. Roundabout construction at an existing intersection requires site-specific staging plans.
Roundabouts create many unique construction challenges and each roundabout has very
site-specific design features.

1010.05(3) Work Duration

The duration of work is a major factor in determining a strategy and the amount and types of
devices to use in traffic control work zones. A project may have work operations with
durations that meet several or all of the following conditions:

1010.05(3)(a) Long-Term Stationary Work Zone

This is work that occupies a location continuously for more than three days. Construction
signs should be post-mounted and larger; more stable channelizing devices should be used
for increased visibility. Temporary barriers, pavement markings, illumination, and other
considerations may be required for long-term stationary work. Staged construction or
temporary alignment/channelization plans are required with this type of work.

1010.05(3)(b) Intermediate-Term Stationary Work Zone

This is work that occupies a location for up to three days. Signs may still be post-mounted if
in place continuously. Temporary pavement markings, in addition to channelization devices,
may be required for lane shifts. Barrier and temporary illumination would normally not be
used in this work zone duration.

1010.05(3)(c) Short-Term Stationary Work Zone

This is work that occupies a location for more than one hour within a single day. At these
locations, all devices are placed and removed during the single period.

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1010.05(3)(d) Short-Duration Work Zone

This is work that occupies a location for up to one hour. Because the work time is short, the
impact to motorists is usually not significant. Simplified traffic control set-ups are allowed, to
reduce worker exposure to traffic. The time it may take to set up a full complement of signs
and devices could approach or exceed the amount of time required to perform the work.
Short-duration work zones usually apply to maintenance work and are not used on
construction projects. (See Work Zone Traffic Control Guidelines for more information.)

1010.05(3)(e) Mobile Work Zone

This is work that moves intermittently or continuously. These operations often involve
frequent stops for activities such as sweeping, paint striping, litter cleanup, pothole patching,
or utility operations, and they are similar to short-duration work zones. Truck-mounted
attenuators, warning signs, flashing vehicle lights, flags, and channelizing devices are used,
and they move along with the work. When the operation moves along the road at low
speeds without stopping, the advance warning devices are often attached to mobile units
and move with the operation.
Pavement milling and paving activities are similar to mobile operations in that they can
progress along a roadway several miles in a day. These operations, however, are not
considered mobile work zones, and work zone traffic control consistent with construction
operations is required.

1010.05(4) Transportation Management Plan (TMP) Strategies

With a completed impacts assessment, strategy development can begin. There are often
several strategies to address a work zone impact, and engineering judgment will be needed
in selecting the best option. Constructability, along with addressing safety and mobility, is the
goal. Selecting a strategy is often a compromise and involves many engineering and non-
engineering factors. Work closely with bridge, construction, maintenance and traffic office
personnel when selecting and developing strategies for the TMP and PS&E.

Do not assume that strategies chosen for past projects will adequately address the impacts
for similar current projects. There may be similarities with the type of work, but each project
is unique and is to be approached in that manner. Always look for other options or
innovative approaches; many projects have unique features that can be turned to an
advantage if carefully considered. Even a basic paving project on a rural two-lane highway
may have opportunities for detours, shifting traffic, or other strategies.

The Traffic Manual contains comprehensive information regarding work zone traffic analysis
to determine expected delay and queuing.

For a list of work zone analysis tools, see:

 http://ops.fhwa.dot.gov/wz/traffic_analysis/index.htm#tools

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1010.05(5) Temporary Traffic Control (TTC) Strategies

1010.05(5)(a) Lane Closure

When one or more traffic lanes are closed, a capacity analysis is necessary to determine the
extent of congestion that may result. Night work or peak hour work restrictions may be
required if the analysis shows adverse traffic impacts. On highways with speeds over 40
MPH, traffic safety drums and truck-mounted attenuators should be used in lane closures
and the drums should not encroach on the open lanes. Additional lanes should be closed if
encroachment is necessary. Consider closing additional lanes to increase the lateral buffer
space for worker safety.

1010.05(5)(b) Shoulder Closure

A shoulder closure is used for work areas off the traveled way. On high-volume freeways or
expressways, they should not be allowed during peak traffic hours. Channelization devices
should not encroach on the open lanes of roadways with speeds of 45 mph and above.

1010.05(5)(c) Alternating One-Lane Two-Way Traffic

This strategy involves using one lane for both directions of traffic. Flaggers are used to
alternate the traffic movements.
If flaggers are used at an intersection, a flagger is required for each leg of the intersection.
Only law enforcement personnel are allowed to flag from the center of an intersection. Close
lanes and turn pockets so only one lane of traffic approaches a flagger station. When a signal
is present, it shall be turned off or set to red flash mode when flagging.
Law enforcement personnel may be considered for some flagging operations and can be very
effective where additional driver compliance is desired. The Traffic Manual contains
information on the use of law enforcement personnel at work zones.
Flagger safety is a high emphasis area. Do not include alternating traffic with flaggers as a
traffic control strategy until all other reasonable means of traffic control have been
considered. Flagging stations need to be illuminated at night. Flaggers need escape routes in
case of errant vehicles. Provide a method of alerting them to vehicles approaching from
behind. Two-way radios or cellular phones are required to allow flaggers to communicate
with one another. The flagger’s location, escape route, protection, signing, and any other
safety-related issues all need to be incorporated into the traffic control plan for the flagging
operation. Flaggers are not to be used on freeways or expressways. Using flaggers solely to
instruct motorists to proceed slowly is an unacceptable practice.
Removing flaggers from the roadway during alternating traffic operations can be done with
portable temporary traffic control signals or automated flagging assistance devices (AFAD).
Portable signals work best when the length between signals will be 1,500 feet maximum and
no accesses lie between the temporary signals. Each AFAD unit will need a flagger operating
the device from a safe location off the roadway. A traffic control plan should show the
advance signing and the AFAD or signal locations. Temporary stop bars, and lighting at the

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stop bars is required for signal use. For assistance on using these devices, contact the region
Traffic Office.
Refer to WAC 296-155-305 for flagging requirements.

1010.05(5)(d) Temporary Alignment and Channelization

Temporary alignments and/or channelization may be an option for long-term work zones or
staged traffic control. The following are guiding principles for the design of temporary
alignment and channelization plans:
 Use site-specific base data to develop site-specific traffic control plans.
 Use permanent geometric design criteria.
 Provide beginning and ending station ties and curve data.
 Include lane and shoulder widths.
 Provide temporary roadway sections.
 To avoid confusion, do not show existing conflicting or unnecessary details on the
plan.
 Do not use straight line tapers through curves; use circular alignment.
 Be aware of existing crown points, lane/shoulder cross slope breaks, and super-
elevation transitions that may affect a driver’s ability to maintain control of a vehicle.
 If the project has multiple stages, from one stage to the next, show newly
constructed features as existing elements. For example, if an edge line is removed in
one stage, the following stage would show the change by indicating where the new
edge line is located.
 Consider the time needed for removal of existing markings and placement of the
new markings and possibly placement of barriers and attenuators. In urban areas
where work hours for lane closures are limited, special consideration may be
necessary to allow time to implement the plan, or an interim stage may be
necessary.
 Use shoulder closure signing and channelizing devices to close a shoulder prior to a
temporary impact attenuator and run of temporary concrete barrier.
 Existing signing may need to be covered or revised, and additional construction
warning signs may be needed for the new alignment.
 Temporary pavement marking types and colors should be specified. Long-duration
temporary markings should be installed per the Standard Plans for permanent
markings.
 For better guidance through shifting or taper areas, consider solid lane lines. Return
to broken lane lines between shift areas.
 Provide a list of the approved temporary impact attenuators that may be used for
the plan if applicable.
 The plans must provide all the layout information for all the temporary features just
as a permanent pavement marking plan would.

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1010.05(5)(d)(1) Staged Construction

Staged construction entails combining multiple work areas into a logical order to provide
large protected work areas for long durations, which maximizes work operations and
minimizes daily impacts to traffic. Temporary alignment and channelization plans must
be designed to place traffic in these semi-permanent locations. Minimum geometric
design criteria are to be used when developing these plans. Design strategies such as
overbuilding for future stages or the use of temporary structures are often part of staged
construction on significant impact projects or mega projects. Develop detailed capacity
analysis and traffic modeling for each stage.

1010.05(5)(d)(2) Lane Shift/Reduced Lane Width

Traffic lanes may be shifted and/or width-reduced in order to accommodate a long-

duration work area when it is not practicable, for capacity reasons, to reduce the number
of available lanes. Shifting more than one lane of traffic requires the removal of
conflicting pavement markings and the installation of temporary markings; the use of
channelization devices to delineate multiple lanes of traffic is not allowed. Use advanced
warning signs to show the changed alignment when the lateral shifting distance is
greater than one-half of a lane width, and consider the use of solid lane lines through the
shift areas.

Utilizing the existing shoulder may be necessary to accommodate the shifting movement.
First, determine the structural capacity of the shoulder to ensure its ability to carry the
proposed traffic. Remove and inlay existing shoulder rumble strips prior to routing traffic
onto the shoulder.

1010.05(5)(d)(3) Traffic Split or Island Work Zone

This strategy separates lanes of traffic traveling in one direction around a work area. On
higher-speed roadways, temporary barriers are provided to prevent errant vehicles from
entering the work area. Some drivers have difficulty understanding "lane split"
configurations, which sometimes results in poor driving decisions such as unnecessary or
late lane changes. Braking and erratic lane changes decrease the traffic capacity through
the work zone, which results in an unstable traffic flow approaching the lane split.
Evaluate other strategies, such as overbuilding, to keep traffic on one side of the work
area to avoid a traffic split if possible.

Consider the following guidance for traffic split operations:

 Define the work operation and develop the traffic control strategy around the
specific operation.

 Limit the duration the traffic split can be in place. Consider incentives and
disincentives to encourage the contractor to be as efficient as possible. A higher
level of traffic impacts may be acceptable if offset with fewer impacted days.

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 Advance warning signs advising drivers of the approaching roadway condition

are required. Consider the use of Portable Changeable Message Signs (PCMS),
portable Highway Advisory Radio (HAR), and other dynamic devices. Overhead
signing and in-lane pavement markings also may be necessary to give additional
driver notice of the traffic split.
 Consider how the operation will impact truck traffic. If the truck volumes are
high, additional consideration may be prudent to control in which lane the
trucks drive. If the trucks are controlled, it eliminates much of the potential for
truck/car conflicts and sorts out undesirable truck lane changes through the
work zone. For questions concerning truck operations, contact the HQ Freight
Systems Division.
 To discourage lane changing, consider the use of solid lane line markings to
delineate traffic approaching the split or island. Refer to the MUTCD for
additional details.
 Consider the use of STAY IN LANE (black on white) signs, or set up a "no pass"
zone approaching the lane split and coordinate with the Washington State
Patrol (WSP).

 Supplement the existing roadway lighting with additional temporary lighting to

improve the visibility of the island work area (see exhibit in Chapter 1040).
 Coordinate with the region Traffic Office for signing and pavement marking
details when designing island work zones.

1010.05(5)(d)(4) Temporary Bypass

This strategy involves total closure of one or both directions of travel on the roadway.
Traffic is routed to a temporary bypass usually constructed within the highway right of
way. An example of this is the replacement of an existing bridge by building an adjacent
temporary structure and shifting traffic onto the temporary structure. A temporary
channelization plan will show pavement markings, barrier and attenuators, sign and
device placement.

1010.05(5)(d)(5) Median Crossover

This strategy involves placing all multilane highway traffic on one side of the median.
Lanes are usually reduced in both directions and one direction is routed across the
median. The design for elements of temporary crossovers needs to follow the same
guidance as permanent design for alignment, barriers, delineation, and illumination.
 Design crossovers for operating speeds not less than 10 mph below the posted
speed limit unless unusual site conditions require a lower design speed.
 Median paving may be required to create crossover locations (consider
drainage for the added pavement).

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 Use temporary barrier to separate the two directions of traffic normally

separated by a median barrier,
 Temporary illumination at the crossover locations (see exhibit in Chapter 1040)

 Straight line crossover tapers work best for highways with narrow paved
medians.
 Temporary pavement markings, removal of conflicting existing markings, and
construction signs are also required.
 A good array of channelizing devices and properly placed pavement markings is
essential in providing clear, positive guidance to drivers.

 Provide a clear roadside recovery area adjacent to the crossover. Consider how
the roadway safety hardware (guardrail, crash cushions, and so on) may be
impacted by the traffic using the crossover if the traffic is going against the
normal traffic flow direction. Avoid or mitigate possible snagging potential.
Avoid placing crossover detours near structures.

1010.05(5)(e) Total Closures and Detours

Total closures may be for the project duration or for a critical work operation that has major
constructability or safety issues. The main requirement for total closures is the availability of
a detour route and if the route can accommodate the increased traffic volumes and trucks
turning movements. Local roads may have lower geometric criteria than state facilities.
Placing additional and new types of traffic on a local road may create new safety concerns,
especially when drivers are accustomed to the geometrics associated with state highways.
Pavement integrity and rehabilitation may need to be addressed when traffic is detoured to
specific local roadways.
For the traveling public, closing the road for a short time might be less of an inconvenience
than driving through a work zone for an extended period of time (see the Traffic Manual and
RCW 47.48). Advance notification of the closure is required, and a signed detour route may
be required.
Consider the following road closure issues:
 Communication with all stakeholders, including road users, adjoining property
owners, local agencies, transit agencies, the freight industry, emergency services,
schools, and others, is required when considering a total closure strategy. This helps
determine the level of support for a closure and development of an acceptable
closure. Include Rail, Freight, and Ports; Commercial Vehicle Services; and Public
Transportation Divisions to help coordinate.
 Analyze a closure strategy and compare it to other strategies, such as staged work
zones, to determine which is overall more beneficial. This information helps
stakeholders understand the impacts if a closure is not selected.

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 A closure decision (other than short-term, minor-impact closures) will require

stakeholder acceptance and management approval once impacts and benefits have
been analyzed.
 Closures that reopen to a new, completed roadway or other noticeable
improvements are generally more accepted by the public.
 Route-to-route connections and other strategic access points may have to be
maintained or a reasonable alternative provided.
 Material selection, production rates, and work operation efficiencies have a direct tie
to the feasibility of the closure strategy. A strong emphasis has been placed on this
area and several successful strategies have been implemented, such as weekend-
long closures or extended-duration single-shift closures. These strategies use specific
materials such as quick-curing concrete, accelerated work schedules, prefabricated
structure components, on-site mix plants, and so on, and are based on actual
production rates. The WSDOT Materials Laboratory and the HQ Construction Office
are good resources for more information on constructability as a component of an
effective work zone strategy.
 Interstate or interstate ramp closures (including interstate closures with interchange
ramps as detours) lasting more than 7 days require FHWA 60-day advance notice.
(See the Stewardship and Oversight Agreement for closure notification
requirements.)
 Short-duration closures of ramps or intersecting streets during off-peak hours do not
require extensive approval if advance notice is provided and reasonable alternate
routes are available.
 Detailed, project-specific traffic control plans, traffic operation plans, and public
information plans are required.
 Depending on the duration of the closure/detour and the anticipated amount and
type of traffic that will use the route, consider upgrades to the route such as signal
timing, intersection turning radius for large vehicle, structural pavement
enhancements, or shoulder widening.
 An approved detour agreement with the appropriate local agency is required for
detour routes using local roadways and must be completed prior to project
advertisement.
 Document road closure decisions and agreements in the Project File.

1010.05(5)(f) Intermittent Closure

This involves stopping all traffic for a short time to allow the work to proceed. Traffic
volumes will determine the allowed duration of the closures. Typically, the closure would be
limited to a ten-minute maximum and would occur in the lowest traffic volume hours.
Equipment crossing and material delivery are where this type of closure may work well.
Traffic is reduced to a single lane on a multilane highway, and a flagger or law enforcement is
used to stop traffic.

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1010.05(5)(g) Rolling Slowdown

Rolling slowdowns are commonly practiced by the Washington State Patrol (WSP) for
emergency closures. They are a legitimate form of traffic control for contractors or utility and
highway maintenance crews for very specific short-duration closures (to move large
equipment across the highway, to pull power lines across the roadway, to switch traffic onto
a new alignment, and so on). They are not to be used for routine work that can be addressed
by lane closures or other formal traffic control strategies. Traffic control vehicles, during off-
peak hours, form a moving blockade, which reduces traffic speeds and creates a large gap (or
clear area) in traffic, allowing very short-term work to be accomplished without completely
stopping the traffic.
Consider other forms of traffic control as the primary choice before the rolling slowdown. A
project-specific traffic control plan (TCP) must be developed for this operation. The TCP or
contact provisions should list the work operations in which a rolling slowdown is allowed.
The gap required for the work and the location where the rolling slowdown begins needs to
be addressed on the TCP. Use of the WSP is encouraged whenever possible. Refer to the
Standard Specifications and Work Zone Traffic Control Guidelines for additional information
on rolling slowdown operations.

1010.05(5)(h) Pedestrian and Bike Detour Route

When existing pedestrian access routes and bike routes are disrupted due to construction
activities, address detour routes with a traffic control plan. The plan must show enough
detail and be specific enough to address the conflicts and ensure the temporary route is
reasonably safe and adequate to meet the needs of the user. Also, consider the impacts to
transit stops for pedestrians: Will the bus stops be able to remain in use during construction
or will adjustments be necessary? (See Chapter 1510 for pedestrian work zone design
requirements.)

1010.05(5)(i) Alternative Project Delivery

To reduce construction times and minimize impacts to the traveling public, consider
alternative delivery techniques to accomplish this. For more information, see:
 http://www.wsdot.wa.gov/projects/delivery/alternative/

1010.05(5)(j) Innovative Design/Construction Methods

 Overbuild beyond normal project needs to maintain additional traffic or facilitate
staged construction.
 Replace bridges using new alignments so they can be built with minimal impacts.
 Bring adjacent lifts of hot mix asphalt (HMA) to match the latest lifts (lag up), and
require a tapered wedge joint to eliminate drop-off and abrupt lane edges to
improve motorist safety.

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 Require permanent pavement markings at intervals during multi-season projects to

limit the duration temporary markings are needed and to avoid temporary marking
issues during winter shut-down.

1010.05(6) Transportation Operations (TO) Strategies

The following are operational strategies to consider based on project specific needs:

1010.05(6)(a) Demand Management

 Provide transit service improvements and possible incentives to help reduce
demand.
 For long-term freeway projects, consider ramp metering.
 Provide a shuttle service for pedestrians and bicyclists.
 Provide local road improvements (signals modifications, widening, and so on) to
improve capacity for use as alternate routes.
 Provide traffic screens to reduce driver distraction.

1010.05(6)(b) Corridor/Network Management

 Provide a temporary express lane with no access through the project.
 Consider signal timing or coordination modifications.
 Provide emergency pullouts for disabled vehicles on projects with long stretches of
narrow shoulders and no other access points.
 Use heavy-vehicle restrictions and provide alternate routes or lane use restrictions.

1010.05(6)(c) Work Zone Safety Management

 Provide temporary access road approaches for work zone access.
 Use positive protective devices (barrier) for long-term work zones to improve the
environment for workers and motorists.
 Install intrusion alarms or vehicle arresting devices.
 Use speed limit reductions when temporary conditions create a need for motorist
slow-downs. Refer to the Traffic Manual for additional information, guidance and
approval requirements for speed limit reductions in work zones.
 Use advanced queue warning systems depending on the extent of expected work
zone congestion on high-speed roadways. Refer to the Traffic Manual for additional
information and guidance for Smart Work Zone Systems and other simpler
truck-mounted PCMS versions.

1010.05(6)(d) Traffic/Incident Management and Enforcement

 Provide law enforcement patrols to reduce speeding and aggressive drivers.
 Provide incident response patrols during construction to reduce delays due to
collisions in the work zone.

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 Include work zone ITS elements in the project or coordinate with TMC to use existing
equipment.
 Provide a dedicated tow service to clear incidents.

1010.05(7) Public Information (PI) Strategies

The following are strategies to consider based on project specific needs:

1010.05(7)(a) Public Awareness

One PI strategy is a public awareness campaign using the media, project websites, public
meetings, e-mail updates, and mailed brochures. This gives regular road users advance notice
of impacts they can expect and time to plan for alternate routes or other options to avoid
project impacts. Involve the region or HQ Communications Office in developing and
implementing these strategies. Coordinate transit travel information and restrictions with
the Public Transportation Division.  http://wwwi.wsdot.wa.gov/PubTran/
Coordinate freight travel information and restrictions with the Rail, Freight, and Ports
Division.
 http://www.wsdot.wa.gov/freight/
 http://www.wsdot.wa.gov/Freight/Trucking/default

1010.05(7)(b) Driver Information

In addition to work zone signs, provide driver information using highway advisory radio (HAR)
and changeable message signs (existing or portable). Include a Smart Work Zone System to
provide drivers with real time information on queuing and delays. Involve the region TMC in
the development and implementation of these strategies. Additional information on smart
work zone systems can be found on the Work Zone Safety web page:
 www.wsdot.wa.gov/safety/workzones/
The Freight Alert system should be used to communicate information with freight industry
on work zones. Each region has the capability to send alerts with this system.
 http://www.wsdot.wa.gov/freight/
Work zone strategy development is a fluid process and may be ongoing as project
information and design features are developed during the design process. There may be
many factors involved with strategy development, and it is necessary to be well organized to
make sure all the relative factors are identified and evaluated.

1010.05(7)(c) Pedestrian and Bicycle Information

Include pedestrian and bicycle access information and alternate routes in the public
awareness plans. Pedestrian and bicyclist information signing, including alternate route maps
specifically for these road users, could be considered.

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1010.06 Work Zone Capacity Analysis

Work zone congestion and delay is a significant issue for many highway projects. At high-
volume locations with existing capacity problems, even shoulder closures will increase
congestion.
All work zone traffic restrictions need to be analyzed to determine the level of impacts.
Short-term lane closures may only require work hour restrictions to address delays; long-
term temporary channelization, realignments, lane shifts, and more will require a detailed
capacity analysis to determine the level of impact. Demand management and public
information strategies may be required to address delays. Traffic capacity mitigation
measures are important since many projects cannot effectively design out all the work zone
impacts. Include a Work Zone & Traffic Analysis in the TMP.
Work zone mobility impacts can have the following effects:
 Crashes: Most work zone crashes are congestion-related, usually in the form of rear-
end collisions due to traffic queues. Traffic queues beyond the advance warning signs
increase the risk of crashes.
 Driver Frustration: Drivers expect to travel to their destinations in a timely manner.
If delays occur, driver frustration can lead to aggressive or inappropriate driving
actions.
 Constructability: Constructing a project efficiently relies on the ability to pursue
work operations while maintaining traffic flow. Delays in material delivery, work hour
restrictions, and constant installation and removal of traffic control devices all
detract from constructability.
 Local Road Impacts: Projects with capacity deficiencies can sometimes cause traffic
to divert to local roadways, which may impact the surrounding local roadway system
and community.
 Public Credibility: Work zone congestion and delay can create poor credibility for
WSDOT with drivers and the surrounding community in general.
 Restricted Access: Severe congestion can effectively gridlock a road system,
preventing access to important route connections, businesses, schools, hospitals,
and so on.
 User Cost Impacts: Traffic delays have an economic impact on road users and the
surrounding community. Calculated user costs are part of a work zone capacity
analysis and may be used to determine liquidated damages specifications.
WSDOT has a responsibility to maintain traffic mobility through and around its projects. The
goal is to keep a project’s work zone traffic capacity compatible with existing traffic
demands. Maintaining the optimum carrying capacity of an existing facility during
construction may not be possible, but an effort must be made to maintain existing traffic
mobility through and/or around the work zone.
Maintaining mobility does not rule out innovative strategies such as roadway closures.
Planned closures can accelerate work operations, reducing the duration of impacts to road

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users. These types of traffic control strategies must include demand management and public
information plans to notify road users and mitigate and manage the impacts as much as
possible.
A work zone capacity analysis helps determine whether a work zone strategy is feasible.
Mitigation measures that provide the right combination of good public information, advance
signing and notification, alternate routes, detours, and work hour restrictions, as well as
innovations such as strategic closures, accelerated construction schedules, or parallel
roadway system capacity improvements, can be very effective in reducing mobility impacts.
Some of the impact issues and mitigating measures commonly addressed by traffic analyses
include:
 Work hour time restrictions
 Hourly liquidated damage assessment
 Use of staged construction
 Working day assessment
 Public information campaign
 User cost assessment
 Local roadway impacts
 Special event and holiday time restrictions
 Closure and detour options
 Mitigation cost justification
 Level of service
 Queue lengths
 Delay time
 Running speed
 Coordination with adjoining projects (internal and local agency)
Many projects will have several potential work zone strategies, while other projects may only
have one obvious work zone strategy. It is possible that a significant mobility impact strategy
may be the only option. TMP strategies still need to be considered. An analysis will help show
the results of these mitigating measures.
There is no absolute answer for how much congestion and delay are acceptable on a project;
it may ultimately become a management decision.
Reductions in traffic capacity are to be mitigated and managed as part of the TMP. The traffic
analysis process helps shape the TMP as the work zone strategies are evaluated and refined
into traffic control plans and specifications. Maintain analysis documents in the Project File.

1010.06(1) Collecting Traffic Volume Data

Current volume data in the project vicinity is required for accurate traffic analysis results.
Seasonal adjustment factors may be needed depending on when the data was collected and
when the proposed traffic restrictions may be in place. Assess existing data as early as
possible to determine whether additional data collection may be required. The region Traffic

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Office and the HQ Transportation Data & GIS Office can assist with collecting traffic volume
data. Coordination with local agencies may be needed to obtain data on affected local roads.
Refer to the Traffic Manual for additional information and guidance.

1010.06(2) Short-Term Work Zone Traffic Analysis

Refer to the Traffic Manual for comprehensive work zone capacity information in addition to
work zone queue and delay estimation calculations.
For short-term lane closures on multilane highways or alternating one-way traffic on two-
lane highways, see Exhibit 1010-1. It provides information for a quick analysis when
compared to current hourly volumes on the highway. The basic traffic analysis programs
QUEWZ 98, along with hourly volume input, the number of lanes to be closed, the hours of
closure, and other default information, will output queue length, delay time, user costs, and
running speed.

Exhibit 1010-1 General Lane Closure Work Zone Capacity

Roadway Type Work Zone Capacity

Multilane Freeways/Highways 1300 VPHPL*

Multilane Urban/Suburban 600 VPHPL*

Two-Lane 400 VPHPL/

Rural Highway 800 VPH total*

*These are average capacity values. The actual values would be dependent on several factors, which
include the existing number of lanes, number of lanes closed, traffic speed, truck percentage,
interchanges/intersections, type of work, type of traffic control, and seasonal factors (among others).
For further information, consult the Highway Capacity Manual.

1010.06(3) Long-Term Work Zone Traffic Analysis

For complex strategies that change traffic patterns, a more detailed analysis is required using
advanced traffic modeling software. These strategies could include reducing lane and
shoulder widths for extended lengths, reducing the number of lanes for extended durations,
moving all lanes of traffic onto a temporary alignment, changing access locations to and from
the highway, or closures with detours (including public information and traffic operation
plans with anticipated reduction in demand). Work with the region Traffic Office for
assistance with this level of analysis.

Refer to the Traffic Manual for additional information and guidance.

The following resources are also available to assist with the actual analysis and mitigation
strategy development upon request:
HQ Transportation Data & GIS Office
HQ Traffic Offices

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Region Work Zone Specialist

Region Public Information Office

Training is also available to obtain further knowledge and expertise in traffic analysis (see
1010.12).

1010.07 Work Zone Design

Part 6 of the MUTCD mostly addresses short-duration temporary traffic control standards.
Some long-duration work zones may require temporary alignments and channelization,
including barrier and attenuator use, temporary illumination and signals, and temporary
pedestrian and bicycle routes. Refer to the Design Manual’s chapters for permanent features
for design guidance.

1010.07(1) Lane Widths

Maintain existing lane widths during work zone operations whenever practicable.
For projects that require lane shifts or narrowed lanes due to work area limits and staging,
consider the following before determining the work zone lane configurations to be
implemented:
 Overall roadway width available
 Posted speed limit
 Traffic volumes through the project limits
 Number of lanes
 Existing lane and shoulder widths
 Crown points and shoulder slope breaks
 Treat lane lines and construction joints to provide a smooth flow
 Length and duration of lane width reduction (if in place)
 Roadway geometry (cross slope, vertical and horizontal curves)
 Vertical clearances
 Transit and freight vehicles, including over-sized vehicles
Work zone geometric transitions should be minimized or avoided if possible. When
necessary, such transitions should be made as smoothly as the space available allows.
Maintain approach lane width, if possible, throughout the connection. Design lane width
reductions prior to any lane shifts within the transition area. Do not reduce curve radii and
lane widths simultaneously.
When determining lane widths, the objective is to use lane geometrics that will be clear to
the driver and keep the vehicle in the intended lane. In order to maintain the minimum lane
widths, temporary widening may be needed.

1010.07(2) Buffer Space

Buffer spaces separate road users from the work space or other areas off limits to travel.
Buffer spaces also might provide some recovery space for an errant vehicle.

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 A lateral buffer provides space between the vehicles and adjacent work space, traffic
control device, or a condition such as an abrupt lane edge or drop-off. As a minimum,
a 2-foot lateral buffer space is used. Positive Protective Devices may be required if
workers are within one lane width of traffic. When temporary barriers are used,
place a temporary edge line 2-foot laterally from the barrier.
 When feasible, a longitudinal buffer space is used immediately downstream of a
closed or shifted traffic lane or shoulder. This space provides a recovery area for
errant vehicles as they approach the work space.
Devices used to separate the driver from the work space should not encroach into adjacent
lanes. If encroachment is necessary, it is recommended to close the adjacent lane to
maintain the lateral buffer space.
In order to achieve the minimum lateral buffer, there may be instances where pavement
widening or a revision to a stage may be necessary. In the case of short-term lane closure
operations, the adjacent lane may need to be closed or traffic may need to be temporarily
shifted onto a shoulder to maintain a lateral buffer space. During the design of the traffic
control plan, the lateral buffer needs to be identified on the plan to ensure additional width
is available; use temporary roadway cross sections to show the space in relation to the traffic
and work area.

1010.07(3) Work Zone Clear Zone

The contractor’s operations present opportunities for errant vehicles to impact the clear area
adjacent to the traveled way. A work zone clear zone (WZCZ) is established for each project
to ensure the contractor’s operations provide an appropriate clear area. The WZCZ addresses
items such as storage of the contractor’s equipment and employee’s private vehicles and
storage or stockpiling of project materials. The WZCZ applies during working and nonworking
hours and applies only to roadside objects introduced by the contractor’s operations. It is not
intended to resolve preexisting deficiencies in the Design Clear Zone or clear zone values
established at the completion of the project. Those work operations or objects that are
actively in progress and delineated by approved traffic control measures are not subject to
the WZCZ requirements.
Minimum WZCZ values are presented in Exhibit 1010-2. WZCZ values may be less than Design
Clear Zone values due to the temporary nature of the construction and limitations on
horizontal clearance. To establish an appropriate project-specific WZCZ, it may be necessary
to exceed the minimum values. The following conditions warrant closer scrutiny of the WZCZ
values, with consideration of a wider clear zone:
 Outside of horizontal curves or other locations where the alignment presents an
increased potential for vehicles to leave the traveled way.
 The lower portion of long downgrades or other locations where gradient presents an
increased potential for vehicles to exceed the posted speed.

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 Steep fill slopes and high traffic volumes. (Although it is not presented as absolute
guidance, the Design Clear Zone exhibit in Chapter 1600 may be used as a tool to
assess increases in WZCZ values.)

Exhibit 1010-2 Minimum Work Zone Clear Zone Distance

Posted Speed Distance From Traveled Way (ft)

35 mph or less 10
40 mph 15
45 to 55 mph 20
60 mph or greater 30

1010.07(4) Abrupt Lane Edges and Drop-offs

Minimize, mitigate, or eliminate abrupt lane edges and drop-offs whenever practicable.
When unavoidable, traffic control plans should provide a protection method. Consider
temporary barriers for long duration drop off protection and contract provisions limiting the
duration of edges from daily paving operations consistent with Standard Specification section
1-07.23(1).

When a temporary barrier is used to protect the drop-off, the back side the barrier shall be
placed a minimum of 3-feet from the drop-off and a new edge line is required on the traffic
side of the barrier with a 2-foot lateral buffer space minimum. The space behind the barrier
can be reduced if the barrier is anchored. Barrier end attenuators may be required.

Open trenches within the traveled way or auxiliary lane shall have a steel-plate cover placed
and anchored over them. A wedge of suitable material, if required, shall be placed for a
smooth transition between the pavement and the steel plate. Warning signs shall be used to
alert motorists of the presence of the steel plates.

Abrupt lane edges, and drop-offs and steel plates require additional warning and
considerations for motorcyclists, bicyclists, and pedestrians, including pedestrians with
disabilities. Adequate signing to warn the motorcycle rider, bicyclists and pedestrians,
including pedestrians with disabilities of these conditions is required. (See RCW 47.36.200
and WAC 468-95-305.) See Design Manual Chapter 1510 for work zone pedestrian
accommodation guidance.

See Standard Specifications section 1-07.23(1) for the contract requirements for drop off
protection and address project specific protection if necessary.

1010.07(5) Vertical Clearance

In accordance with Chapter 720, the minimum vertical clearance over new highways is 16.5
feet. Anything less than the minimum must follow the reduced clearance criteria discussed in
Chapter 720 and be included in the temporary traffic control plans. Maintain legal height on
temporary falsework for bridge construction projects. Anything less than this must consider

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over-height vehicle impacts and possible additional signing needs and coordination with
permit offices. Widening of existing structures can prove challenging when the existing
height is at or less than legal height, so extra care is required in the consideration of over-
height vehicles when temporary falsework is necessary. Coordination with the HQ Bridge and
Structures Office is essential to ensure traffic needs have been accommodated. Vertical
clearance requirements associated with local road networks may be different than what is
shown in Chapter 720. Coordinate with the local agency.

1010.07(6) Reduced Speeds in Work Zones

Drivers tend to reduce their speed only if they perceive a need to do so. Reduced speed
limits should only be used to address an altered geometry when not able to meet design
standards for the existing speed, when the roadway will be narrowed with minimal shy
distance to barriers, when roadway conditions warrant a reduction like BST operations, and
when there will be workers on foot within a lane width of high-volume traffic traveling at 45
mph and above without positive protection devices in place. Speed reductions are not
applied as a means for selecting lower work zone design criteria (tapers, temporary
alignment, device spacing, and so on).

Speed limit reductions are categorized as follows:

Continuous Regulatory Speed Limit Reduction: A speed reduction in place 24 hours a
day for the duration of the project, stage, or roadway condition.
Variable Regulatory Speed Limit Reduction: A speed reduction in place only during
active work hours (Class B construction signs may be used). This is a good option
when positive protection devices are not used.
Advisory Speed Reduction: In combination with a warning sign, an advisory speed
plaque may be used to indicate a recommended safe speed through a work zone or
work zone condition. Refer to the MUTCD for additional guidance.

Refer to the Traffic Manual for additional information, guidance and approval requirements
for speed limit reductions in work zones. Include approval documents in the Project File.

1010.07(7) Accommodation for Pedestrians and Bicyclists

Many public highways and streets accommodate pedestrians and bicyclists, predominately in
urban areas. During construction, access must be maintained through or around the work
zones. When existing pedestrian routes that are accessible to pedestrians with disabilities are
closed, the alternate routes must be designed and constructed to meet or exceed the
existing level of accessibility. Temporary pedestrian facilities within the work zone must meet
accessibility criteria to the maximum extent feasible. (See Chapter 1510 for pedestrian
circulation path and pedestrian access route accessibility criteria.) Covered walkways are to
be provided where there is a potential for falling objects.
In work areas where the speeds are low (25 mph), or the ADT is 2,000 or less, bicyclists can
use the same route as motorized vehicles. For work zones on higher-speed facilities,
bicyclists will need a minimum 4-foot shoulder or detour route to provide passage through or

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around a work zone. Bicyclists may be required to dismount and walk their bikes through a
work zone on the route provided for pedestrians.
It may be possible to make other provisions to transport pedestrians and bicyclists through a
work zone or with a walking escort around the active work area. Roadway surfaces are an
important consideration for pedestrian and bicycle use. Unacceptable conditions such as
loose gravel, uneven surfaces, milled pavement, and asphalt tack coats endanger the bicyclist
and restrict access to pedestrians with disabilities.
Information can be gathered on bike issues by contacting local bike clubs. Coordination with
local bike clubs goes a long way to ensuring their members are notified of work zone
impacts, and it helps maintain good public relations. (See Chapter 1520 for more bicycle
design requirements and Chapter 1510 and MUTCD Chapter 6D for pedestrian work zone
design requirements.)

1010.07(8) Warning Signs for Motorcyclists

The roadway surface condition is a far greater concern for motorcycles requiring additional
warning signs to alert the motorcyclist of work zone conditions. Per RCW 47.36.200
paragraph 2, “(2) If the construction, repair, or maintenance work includes or uses grooved
pavement, abrupt lane edges, steel plates, or gravel or earth surfaces, the construction,
repair, or maintenance zone must be posted with signs stating the condition, as required by
current law, and in addition, must warn motorcyclists of the potential hazard only if the
hazard or condition exists on a paved public highway, county road, street, bridge, or other
thoroughfare commonly traveled. For the purposes of this subsection, the department shall
adopt by rule a uniform sign or signs for this purpose, including at least the following
language, "MOTORCYCLES USE EXTREME CAUTION."

1010.07(9) Oversized Vehicles

The region Maintenance offices and the HQ Commercial Vehicle Services Office issue permits
to allow vehicles that exceed the legal width, height, or weight limits to use certain routes. If
a proposed work zone will reduce roadway width or vertical clearance, or have weight
restrictions, adequate warning signs and notification to the HQ Commercial Vehicle Services
Office and the appropriate region Maintenance Office is required as a minimum. When the
total width of a roadway is to be reduced to less than 16 feet for more than three days,
communication with these offices and any other stakeholders is required; include
documentation in the Project File. The contract documents shall include provisions requiring
the contractor to provide a 30-calendar-day notice prior to placing the restriction.
In the permit notification, identify the type of restriction (height, weight, or width) and
specify the maximum size that can be accommodated. On some projects, it may be necessary
to designate a detour route for oversized vehicles. An important safety issue associated with
oversized loads is that they can sometimes be unexpected in work zones, even though
warning and restriction or prohibition signs may be in place. Some oversized loads can
overhang the temporary barrier or channelization devices and endanger workers. Consider
the potential risk to those within the work zone. Routes with high volumes of oversized loads

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or routes that are already strategic oversized load routes may not be able to rely only on
warning or prohibition signs. Protective features or active early warning devices may be
needed. If the risk is so great that one oversized load could potentially cause significant
damage or injury to workers, failsafe protection measures may be needed to protect
structures and workers. The structure design, staging, and falsework openings may need to
be reconsidered to safely accommodate oversized loads.

1010.08 Temporary Traffic Control Devices

FHWA regulations require that temporary traffic control devices be compliant with the 2016
edition of the Manual for Assessing Safety Hardware (MASH) crash test requirements. In
some cases, either the 2009 MASH or the National Cooperative Highway Research Program
(NCHRP) Report 350 compliant devices may be used. See Standard Specification 1-10.2(3) for
more information.

1010.08(1) Channelizing Devices

Channelizing devices are used to alert and guide road users through the work zone. They are
used to channelize traffic away from the work space, pavement drop-offs, or opposing
directions of traffic. Traffic Safety Drums are the preferred devices on freeways and
expressways as they are highly visible and are less likely to be displaced by traffic wind. 28-
inch cones are also used on WSDOT projects. They are a good choice for flagging operations.
Tall channelization devices are 42-inch cone-type devices and should be used in place of
tubular markers to separate opposing traffic. Tubular markers are not a recommended
device unless they are being used to separate traffic on low-volume low-speed roadways.
Longitudinal channelizing devices are interconnected devices that provide channelization
with no gaps. These devices look like a temporary barrier, but are not approved as a positive
protective device. Barricades are a channelization device mostly used to supplement other
channelization devices in traffic control operations involving road, ramp, or sidewalk
closures.

1010.08(2) Construction Signs

Portable and temporary signs (Class B Construction Signs) are generally used in short-term
work zones. They are set up and removed daily or frequently repositioned as the work moves
along the highway. These signs are mounted on crashworthy, collapsible sign supports. The
minimum mount height is 1 foot above the roadway, but there are temporary sign supports
that will provide 5- to 7-foot mounting heights. This may be useful when temporary signs are
mounted behind channelizing device or in urban areas with roadside parking that may
obstruct sign visibility and multilane facilities. Temporary signs need to be placed such that
they do not obstruct pedestrian facilities. Warning signs in place longer than three days at
one location must be post-mounted.
Fixed signing (Class A Construction Signs) are the signs mounted on conventional sign
supports along or over the roadway. This signing is used for long-term stationary work zones.

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Details for their design are in Chapter 1020 and the Standard Plans. Sign messages, color,
configuration, and usage are shown in the MUTCD and the Sign Fabrication Manual. Existing
signs may need to be covered, removed, or modified during construction.

1010.08(3) Warning Lights

Warning lights are either flashing or steady burn and can be mounted on channelizing
devices, barriers, and signs. Secure crashworthy mounting of warning lights is required.
 Type A: Low-intensity flashing warning light used on a sign or barricade to warn road
users during nighttime hours that they are approaching a work zone.
 Type B: High-intensity flashing warning light used on a sign or barricade to warn road
users during both daytime and nighttime hours.
 Type C and Type D 360 degree: Steady-burn warning lights designed to operate 24
hours a day to delineate the edge of the roadway.

1010.08(4) Arrow Board

The arrow board (Sequential Arrow Sign) displays either an arrow or a chevron pointing in
the direction of the intended route of travel. Arrow board displays are required for lane
closures on multilane roadways. When closing more than one lane, use an arrow board
display for each lane reduction. Place the arrow board at the beginning of the transition
taper and out of the traveled way. The caution display (four corner lights) is only used for
shoulder work. Arrow boards are not used on two-lane two-way roadways.

1010.08(5) Portable Changeable Message Signs (PCMS)

PCMS have electronic displays that can be modified and programmed with specific messages
and may be used to supplement other warning signs. These signs are usually trailer mounted
with solar power and batteries to energize the electronic displays. A two-second display of
two messages is the recommended method to ensure motorists have time to read the sign’s
message twice. These devices are not crashworthy and should be removed when not in use,
or placed behind barrier or guardrail. PCMS are best used to provide notice of unexpected
situations like the potential for traffic delays or queuing and to provide a notice of future
closures or restrictions. They should not be used in place of required signs or to provide
redundant information.

1010.08(6) Portable Temporary Traffic Control Signals

These versatile trailer-mounted portable signals are battery powered, with the ability to be
connected to AC power. They can operate on fixed timing or be traffic actuated. They are
typically used on two-lane two-way highways to alternate traffic in a single lane for extended
durations.

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1010.08(7) Portable Highway Advisory Radio (HAR)

HAR can be used to broadcast AM radio messages about work zone traffic and travel-related
information. The system may be a permanently located transmitter or a portable trailer-
mounted system that can be moved from location to location as necessary. Contact the
region Traffic Office for specific guidance and advice on the use of these systems.

1010.08(8) Automated Flagger Assistance Device (AFAD)

An AFAD is a flagging machine that is operated remotely by a flagger located off the roadway
and away from traffic. This device could be used to enhance safety for flaggers on highways
with reduced sight distance or limited escape routes. A traffic control plan is required for use
of the AFAD. A flagger is required to operate each device.
Refer to the MUTCD for additional guidance on temporary traffic control zone devices.

1010.08(9) Radar Speed Display Sign (RSDS)

RSDS are a work zone speed management device that display motorist’s speed in real time
along with a regulatory speed limit sign or advisory speed sign mounted above the speed
display.
RSDS work best when a single lane of traffic remains open but may be used when multiple
lanes are open. When multiple lanes are open in heavy traffic volume conditions, it may be
unclear which vehicle’s speed is actually displayed.
RSDS are not an automated speed enforcement speed, but a passive feedback system to
drivers. Modest speed reductions of 3 to 6 mph have been recorded when used within an
active work zone.

1010.09 Positive Protection Devices

Channelizing devices may not provide adequate worker and road user protection in some
work zones. Positive protective devices listed in the following sub-sections are needed for
the following conditions unless an engineering study determines otherwise:
 To separate opposing traffic traveling 45 mph and above normally separated by a
median or existing median barrier.
 Where existing traffic barriers or bridge railings are to be removed.
 For drop-off protection during widening or excavations (see Standard Specification 1-
07.23(1)).
 When temporary slopes change clear zone requirements.
 For bridge falsework protection.
 When equipment or materials must remain in the work zone clear zone.
 When newly constructed features in the clear zone will not have permanent
protection until later in the project.
 Where temporary signs or light standards are not crashworthy.

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 To separate workers from motorized traffic when work zone offers no means of
escape for the worker, such as tunnels, bridges, and retaining walls, or for long-
duration worker exposure within one lane-width of high-volume traffic with speeds
of 45 mph and above.

1010.09(1) Temporary Barriers

Providing temporary barrier protection may become the key component of the work zone
strategy. Barrier use usually requires long-term stationary work zones with pavement
marking revisions, and will increase the traffic control costs of a project. The safety benefit
versus the cost of using barrier requires careful consideration, and cost should not be the
only or primary factor determining the use of barrier. (See Chapter 1610 for guidance on
barriers.)

1010.09(1)(a) Concrete Barriers

These are the safety-shape barriers (Type F, Type 2) shown in the Standard Plans. Safety-
shape barriers can be unanchored or anchored. See Chapter 1610 for more detailed
information on these barriers and their deflection characteristics.

1010.09(1)(b) Movable Barrier Systems

Movable barriers are specially designed segmental barriers that can be moved laterally one
lane width or more as a unit with specialized equipment. This allows strategies with frequent
or daily relocation of a barrier. The ends of the barrier must be located out of the clear zone
or fitted with an impact attenuator. Storage sites at both ends of the barrier will be needed
for the barrier-moving machine. WSDOT owns this type of barrier and equipment and it may
be available for project use. Pay items are included in the PS&E to deliver the barrier and
equipment from and back to the WSDOT storage location and for operation and
maintenance during the project.

1010.09(1)(c) Portable Steel Barriers

Portable steel barriers have a lightweight stackable design. They have options for gate-type
openings and relocation without heavy equipment. Steel barriers can be unanchored or
anchored per the manufacturer’s specifications. The lateral displacement of unanchored
steel barriers from vehicle impacts typically ranges from 5 to 8 feet depending on
manufacturer. The lateral displacement of anchored steel barriers from vehicle impacts
typically ranges from 1 to 3 feet depending on manufacturer and anchor pinning
arrangement. Steel barriers are proprietary items. See manufacturer website for more
information.

1010.09(2) Impact Attenuators

Within the Design Clear Zone, the approach ends of temporary barriers shall be fitted with
impact attenuators. The information in Chapter 1620 provides all the necessary impact

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attenuator performance and selection information. In addition to the guidance in Chapter

1620, consider the characteristics of the work zone when selecting an attenuator. Selection
should consider site specific conditions and the dynamic nature of work zones throughout
the project.

Contract plans showing temporary impact attenuator placement need to include a list of the
approved attenuators that a contractor may use for that installation. See the Attenuator
Selection Template at:

http://www.wsdot.wa.gov/publications/fulltext/design/ProductFolder/Impact_attenuator_s
election_template.xlsx

1010.09(3) Transportable Attenuators

A transportable attenuator (TA) is a positive protection device that will provide protection for
the work area only a short distance in front of the device. An impact attenuator device is
attached to the rear of a large truck or towed behind trailer. The minimum truck or trailer
weight is specified by the manufacturer to minimize the roll-ahead distance when impacted
by an errant vehicle. Use a TA on all roadway operations with speeds of 45 mph and above.

1010.10 Other Traffic Control Devices or Features

1010.10(1) Delineation
Temporary pavement markings will be required when permanent pavement markings are
obliterated due to construction operations or temporary reconfigurations needed for long-
term work zone strategies. Temporary pavement markings can be made using paint,
preformed tape, or raised pavement markers. Complex projects will most likely require both
long- and short-duration temporary markings. All temporary pavement markings must be
retroreflective and match permanent pavement marking colors. All conflicting pavement
markings must be completely removed. Temporary pavement markings are installed in
accordance with the Standard Plans and Standard Specifications.

Short-duration temporary pavement markings are made with materials intended to last only
until permanent markings can be installed on paving and BST projects, or for short durations
between construction stages. Short-duration broken line patterns typically consist of a 4-foot
line with a 36-foot gap for paint and tape markings but may be increased to a 10-foot line
with a 30-foot gap when specified in the Contract. Short-duration broken line patterns
consist of a grouping of three raised pavement markings at 3-foot spacing with a 34-foot gap.
Flexible raised pavement markers are required for bituminous surface treatments but
typically are not allowed on other pavement types. Temporary edge lines are installed only
when specified in the plans. When specified, temporary edge lines are either solid lines or
raised pavement markers at 5-foot spacing.

Long-duration temporary pavement markings layouts will match permanent pavement

marking standards and should be used on projects spanning multiple seasons and/or
wintering over. To enhance wet-weather visibility, long-duration temporary pavement
markings should be supplemented with reflective Type 2 Raised Pavement Markers. Long-
duration markings need to be detailed in the contract plans for installation and material type.

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Pre-formed tapes should be used on the final pavement surface to avoid leaving scars when
removed.

Lateral clearance markers are used at the angle points of barriers where they encroach on or
otherwise restrict the adjacent shoulder. Barrier delineation is necessary where the barrier is
less than 4 feet from the edge of traveled way.

Guideposts may be considered to aid nighttime driving through temporary alignments or

diversions. (See Chapter 1030 for delineation requirements.)

1010.10(2) Screening
Screening devices can be used to reduce motorists’ distraction due to construction activities
adjacent to the traveled way. Consider screening when a highway operates near capacity
during most of the day. Screening should be positioned behind traffic barriers to prevent
impacts by errant vehicles and should be anchored or braced to resist overturning when
buffeted by wind. Commercially available screening or contractor-built screening can be
used, provided the device meets crashworthy criteria if exposed to traffic and is approved by
the Engineer prior to installation.
Glare screening may be required on concrete barriers separating two-way traffic to reduce
headlight glare from oncoming traffic. Woven wire and vertical blade-type screens are
commonly used in this installation. This screening also reduces the potential for motorist
confusion at nighttime by shielding construction equipment and the headlights of other
vehicles on adjacent roadways. Make sure that motorists’ sight distance is not impaired by
these glare screens. Contact the HQ Design Office and refer to AASHTO’s Roadside Design
Guide for additional information on screening.

1010.10(3) Illumination
Illumination might be justified if construction activities take place on the roadway at night for
an extended period of time. Illumination might also be justified for long-term construction
projects at the following locations:
 Road closures with detours or diversions.
 Median crossovers on freeways.
 Complex or temporary alignment or channelization.
 Haul road crossings (if operational at night).
 Temporary traffic signals.
 Temporary ramp connections.
 Projects with lane shifts and restricted geometrics.
 Projects with existing illumination that needs to be removed as part of the
construction process.
Illumination is required when:
 Traffic flow is split around or near an obstruction.

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 Flaggers are necessary for nighttime construction activities (supplemental lighting of

the flagger stations by use of portable light plants or other approved methods). Refer
to Standard Specification 1-10.3(1)A.
For information on light levels and other electrical design requirements, see Chapter 1040.

1010.10(4) Signals
A permanent signal system can be modified for a temporary configuration such as temporary
pole locations during intersection construction, span wire systems, and adjustment of signal
heads and alternative detection systems to accommodate a construction stage (see Chapter
1330).

1010.10(5) Smart Work Zone Systems (SWZS)

A Smart Work Zone System uses real time information to optimize the safety and efficiency
of traffic through the work zone.
SWZS can provide information such as queue detection for “slowed or stopped traffic ahead”
messaging before motorists see brake lights, merging instructions (zipper merging where
motorists use all open lanes up to the merge point where they take turns merging) to reduce
the queue lengths, or travel time information so drivers can choose alternate routes.
Portable equipment used in SWZS may include portable changeable message signs, portable
roadside traffic sensors and cameras that communicate wirelessly through a web-based
central management platform. Pre-determined messages will be displayed on the
changeable message signs approaching a work area based on traffic data from the portable
sensors also placed approaching the work area. A SWZS technician will install, program and
monitor the system.
Existing permanent freeway cameras and message boards could also be part of a SWZS;
coordination with the region Traffic Management Center (TMC) will be required to
determine how these devices may be included and the information sharing with the SWZS
and the TMC.

1010.11 Traffic Control Plan Development and PS&E

WSDOT projects need to include plans and payment items for controlling traffic based on a
strategy that is consistent with the project construction elements, even though there may be
more than one workable strategy. A constructible and biddable method of temporary traffic
control is the goal. The contractor has the option of adopting the contract plans or proposing
an alternative method.

1010.11(1) Traffic Control Plans (TCPs)

“Typical” traffic control plans are generic in nature and are not intended to address all site
conditions. They are intended for use at multiple work locations and roadways with little or
no field modifications necessary. Typical plans may be all that are needed for basic paving

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projects. Some typical plans are located at:

 www.wsdot.wa.gov/design/standards/plansheet.htm
“Project-specific” traffic control plans are typical-type plans that have been modified to fit a
specific project or roadway condition. Dimension lines for signs and device placement have
the distances based on the project highway speed limit, and spacing charts have been
removed; the lane and roadway configuration may also be modified to match the project
conditions.
“Site-specific” traffic control plans are drawn for a specific location. Scaled base data drawn
plans will be the most accurate as device placement and layout issues can be resolved by the
designer. These types of plans should be used for temporary alignment and channelization
for long-duration traffic control. Making a “project-specific” plan applicable for a site-specific
location is another option, but the designer must ensure the device layout will match the
site-specific location since the plan is usually not to scale.
The following plans, in addition to the TCP types above addressing the TTC strategies, may be
included in the PS&E.

1010.11(1)(a) Construction Sign Plan

Show Class A Construction Signs that will remain in place for the duration of the project
located by either station or milepost. Verify the locations to avoid conflicts with existing
signing or other roadway features. These locations may still be subject to movement in the
field to fit specific conditions. For simple projects these sign are often shown on the vicinity
map sheet.

1010.11(1)(b) Construction Sign Specification Sheet

Provide a Class A Construction Sign Specifications sheet on complex or staged projects.
Include location, post information, and notes for Standard Plans or other specific sign
information and sign details.

1010.11(1)(c) Quantity Tabulation Sheets

Quantity Tabulation sheets are a good idea for barrier and attenuator items and temporary
pavement markings on projects with large quantities of these items or for staged
construction projects.

1010.11(1)(d) Traffic Control Plan Index

An Index sheet is a useful tool for projects that contain a large quantity of traffic control
plans and multiple work operations at various locations throughout the project. The Index
sheet provides the contractor a quick referencing tool indicating the applicable traffic control
plan for the specific work operation.

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1010.11(1)(e) Construction Sequence Plans

Sequence plans are placed early in the plan set and are intended to show the proposed
construction stages and the work required for each stage. They should refer to the
corresponding TCPs for the traffic control details of each stage.

1010.11(1)(f) Temporary Signal Plan

The temporary signal plan will follow conventions used to develop permanent signals (as
described in Chapter 1330), but will be designed to accommodate temporary needs and work
operations to ensure there will be no conflicts with construction operations. Ensure opposing
left-turn clearances are maintained as described in Chapter 1310 if channelization has been
temporarily revised, or adjust signal timing to accommodate. Some existing systems can be
maintained using temporary span wires for signal heads and video, microwave actuation, or
timed control.

1010.11(1)(g) Temporary Illumination Plan

Full lighting is normally provided through traffic control areas where power is available. The
temporary illumination plan will follow conventions used to develop permanent illumination
(as described in Chapter 1040), but will be designed to accommodate temporary needs and
work operations to ensure there will be no conflicts with construction operations.

1010.11(2) Contract Specifications

Work hour restrictions for lane closure operations are to be specifically identified for each
project where traffic impacts are expected and liquidated damages need to be applied to the
contract. Refer to the Plans Preparation Manual for additional information on writing traffic
control specifications.

1010.11(3) Cost Estimating

Temporary traffic control devices and traffic control labor can be difficult to estimate. There
is no way of knowing how many operations a contractor may implement at the same time.
The best method is to follow the working day estimate schedule and the TCPs that will be
used for each operation. Temporary signs and devices will be used on many plans, but the
estimated quantity reflects the most used at any one time. To use the lump sum item to pay
for all temporary traffic control, be certain how the contractor’s work operations will
progress and that the traffic control plans fully define the work zone expectations.

1010.12 Training and Resources

Temporary traffic control-related training is an important component in an effective work
zone safety and mobility program. Federal regulations require that those involved in the
development, design, implementation, operation, inspection, and enforcement be trained at
a level consistent with their responsibilities.

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1010.12(1) Training Courses

The following work zone related courses are available through the Talent Development office
and the State Work Zone Training Specialist can assist with the availability and scheduling of
classes:
 Work Zone Traffic Control Design: This 2-day course, taught by the HQ Traffic Office,
focuses on work zone safety and mobility through transportation management plan
and temporary traffic control PS&E development.
 Traffic Control Supervisor (TCS) Certification: This course is a 1-day add-on to the
Work Zone Traffic Control Design course for WSDOT employees that want to become
certified as a TCS. For those with a current TCS card, attending this 1-day class only
will provide re-certification.
 Flagger Certification: This course is for employees who may have flagging duties or
want to become a certified Traffic Control Supervisor. The safety offices can assist
with class scheduling.
 Traffic analysis, traffic engineering, pedestrian facilities design and other courses
may also be available and apply to work zone safety and mobility.
The American Traffic Safety Services Association (ATSSA) offers free or low-cost training
through an FHWA work zone safety grant.

1010.12(2) Resources
The responsibility of the designer to fully address all work zone traffic control impacts is very
important because the level of traffic safety and mobility will be directly affected by the
effectiveness of the transportation management plan (TMP). The following resources are
available to assist the designer with various aspects of the work zone design effort.

1010.12(2)(a) Region Work Zone Resources

Each region has individuals and offices with various resources that provide work zone
guidance and direction beyond what may be available at the project Design Office level. They
include:
 Region Traffic Office
 Region Construction and Design Offices

1010.12(2)(b) Headquarters (HQ) Work Zone Resources

The HQ Traffic Office has a work zone team available to answer questions, provide
information, or otherwise assist. The HQ Design and Construction offices may also be able to
assist with some work zone issues. They include:
 State Assistant Traffic Design Engineer
 State Work Zone Engineer
 WSDOT Work Zone Web Page

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1010.12(2)(c) FHWA Work Zone Resources

The FHWA Washington Division Office and Headquarters (HQ) Office may be able to provide
some additional information through the WSDOT HQ Traffic Office. The FHWA also has a
work zone web page:  www.ops.fhwa.dot.gov/wz/

1010.13 Documentation
Refer to Chapter 300 for design documentation requirements.

1010.14 References

1010.14(1) Federal/State Laws and Codes

23 Code of Federal Regulations (CFR) Part 630 Subpart J and Subpart K – Work Zone Safety
and Mobility and Temporary Traffic Control Devices
See Chapter 1510 for Americans with Disabilities Act policy and references.
“Final Rule on Work Zone Safety and Mobility,” Federal Highway Administration (FHWA),
Published on September 9, 2004
 www.ops.fhwa.dot.gov/wz/resources/final_rule.htm
Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as
adopted and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for
streets and highways” (MUTCD)

1010.14(2) Design Guidance

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO
Executive Order E 1001, Work Zone Safety and Mobility
 http://wwwi.wsdot.wa.gov/publications/policies/fulltext/1001.pdf
Executive Order E 1060, Speed Limit Reductions in Work Zones
 http://wwwi.wsdot.wa.gov/publications/policies/fulltext/1060.pdf
Executive Order E 1033, WSDOT Employee Safety
 http://wwwi.wsdot.wa.gov/publications/policies/fulltext/1033.pdf
Plans Preparation Manual, M 22-31, WSDOT
Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-10,
WSDOT
Standard Specifications for Road, Bridge, and Municipal Construction (Standard
Specifications), M 41-10, WSDOT
Traffic Manual, M 51-02, WSDOT
Work Zone Traffic Control Guidelines, M 54-44, WSDOT

1010.14(3) Supporting Information

Construction Manual, M 41-01, WSDOT
“Crashworthy Work Zone Traffic Control Devices,” Report 553, NCHRP, 2006

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Environmental Manual, M 31-11, WSDOT

Highway Capacity Manual, 2010, TRB
ITE Temporary Traffic Control Device Handbook, 2001
ITS in Work Zones  www.ops.fhwa.dot.gov/wz/its/
“Recommended Procedures for the Safety Evaluation of Highway Features,” Report 350,
NCHRP, 1993
Roadside Design Guide, AASHTO, 2011
Manual for Assessing Safety Hardware, AASHTO, 2009
Manual for Assessing Safety Hardware, AASHTO, 2016
Work Zone & Traffic Analysis, FHWA  www.ops.fhwa.dot.gov/wz/traffic_analysis.htm
Work Zone Operations Best Practices Guidebook, FHWA, 2007
 www.ops.fhwa.dot.gov/wz/practices/practices.htm
Work Zone Safety and Mobility, FHWA  www.ops.fhwa.dot.gov/wz/index.asp
Work Zone Safety Web Page, WSDOT  www.wsdot.wa.gov/safety/workzones/
WSDOT Project Management website:  http://www.wsdot.wa.gov/Projects/ProjectMgmt/

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Exhibit 1010-3 Transportation Management Plan Components Checklist

Use the following checklist to develop a formal TMP document on significant projects.

TMP Component √
1. Introductory Material
Cover page
Licensed Engineer stamp page (if necessary)
Table of contents
List of figures
List of tables
List of abbreviations and symbols
Terminology
2. Executive Summary
3. TMP Roles and Responsibilities
TMP manager
Stakeholders/review committee
Approval contact(s)
TMP implementation task leaders (public information liaison, incident management coordinator)
TMP monitors
Emergency contacts
4. Project Description
Project background
Project type
Project area/corridor
Project goals and constraints
Proposed construction phasing/staging
General schedule and timeline
Adjacent projects
5. Existing and Future Conditions
Data collection and modeling approach
Existing roadway characteristics (history, roadway classification, number of lanes, geometrics,
urban/suburban/rural)
Existing and historical traffic data (volumes, speed, capacity, volume-to-capacity ratio, percent trucks,
queue length, peak traffic hours)
Existing traffic operations (signal timing, traffic controls)
Incident and crash data
Local community and business concerns/issues
Traffic growth rates (for future construction dates)
Traffic predictions during construction (volume, delay, queue)
6. Work Zone Impacts Assessment Report
Qualitative summary of anticipated work zone impacts
Impacts assessment of alternative project design and management strategies (in conjunction with
each other)
 Construction approach/phasing/staging strategies
 Work zone impacts management strategies

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Exhibit 1010-3 Transportation Management Plan Components Checklist (continued)

TMP Component √
Traffic analysis results (if applicable)
 Traffic analysis strategies
 Measures of effectiveness
 Analysis tool selection methodology and justification
 Analysis results
Traffic (volume, capacity, delay, queue, noise)
Safety
Adequacy of detour routes
Business/community impact
Seasonal impacts
Cost-effectiveness/evaluation of alternatives
Selected alternative
 Construction approach/phasing/staging strategy
 Work zone impacts management strategies
7. Selected Work Zone Impacts Management Strategies
Temporary Traffic Control (TTC) strategies
 Control strategies
 Traffic control devices
 Corridor Project coordination, contracting, and innovative construction strategies
Public Information (PI)
 Public awareness strategies
 Motorist information strategies
Transportation Operations (TO)
 Demand management strategies
 Corridor/network management strategies
 Work zone safety management strategies
 Traffic/incident management and enforcement strategies
8. TMP Monitoring
Monitoring requirements
Evaluation report of successes and failures of TMP
9. Contingency Plans
Trigger points
Decision tree
Contractor's contingency plan
Standby equipment or personnel
10. TMP Implementation Costs
Itemized costs
Cost responsibilities/sharing opportunities
Funding source(s)
11. Special Considerations (as needed)
12. Attachments (as needed)

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Chapter 1020 Signing
1020.01 General
1020.02 Design Components
1020.03 Overhead Installation
1020.04 State Highway Route Numbers
1020.05 Mileposts
1020.06 Guide Sign Plan
1020.07 Documentation
1020.08 References

1020.01 General
The Washington State Department of Transportation (WSDOT) uses signing as the primary
mechanism for regulating, warning, and guiding traffic. Signing must be in place when any
section of highway is open to the motoring public. Each highway project has unique and specific
signing requirements. For statewide signing uniformity and continuity, it is sometimes necessary
to provide signing beyond the project limits. Design characteristics of the facility determine the
size and legend for a sign. As the design speed increases, larger sign sizes are necessary to
provide adequate message comprehension time. The MUTCD, the Traffic Manual, and the Sign
Fabrication Manual contain standard sign dimensions, specific legends, and reflective sheeting
types for all new signs.

Guide signing provides the motorist with directional information to destinations. This
information is always presented in a consistent manner. In some cases, there are specific laws,
regulations, and policies governing the content of the messages on these signs. All proposed
guide signs for a project require the approval of the region Traffic Engineer. The use of
nonstandard signs is strongly discouraged and their use requires the approval of the State
Traffic Engineer.

Apply the following criteria when determining whether to replace or modify existing signs:
 Current sign’s service life is reached
 Lack of nighttime retroreflectivity
 Substantial damage, vandalism, or deterioration
 Replace signs with Type I sheeting
 Change in sign use policy
 Improper location
 Message or destination changes necessary to satisfy commitments to public or local
agencies
 Substandard mounting height
 Change in jurisdiction (for example, a county road becomes a state route)

Address sign support breakaway features in accordance with Chapter 1600.

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1020.02 Design Components

1020.02(1) Location
The MUTCD contains the guidelines for positioning signs. Check sign locations to ensure the
motorist’s view of the sign is not obscured by other roadside appurtenances. Also, determine
whether the proposed sign will obstruct the view of other signs or limit the motorist’s sight
distance of the roadway. Reposition existing signs, when necessary, to satisfy these visibility
requirements. Where possible, locate signs behind existing traffic barriers, on grade separation
structures, or where terrain features will minimize their exposure to errant vehicles.

1020.02(2) Longitudinal Placement

The MUTCD and the Traffic Manual provide guidelines for the longitudinal placement of signs
that are dependent on the type of sign. Select a location to fit the existing conditions to provide
for visibility and adequate response time. In most cases, signs can be shifted longitudinally to
enhance safety without compromising their intended purpose.

1020.02(3) Lateral Clearance

The Standard Plans and the MUTCD contain minimum requirements for the lateral placement
of signs. Where possible, position the signs at the maximum feasible lateral clearance for safety
and reduced maintenance costs. Locate large guide signs and motorist information signs beyond
the Design Clear Zone (see Chapter 1600) where limited right of way or other physical
constraints are not a factor. On steep fill slopes, an errant vehicle is likely to be partially airborne
from the slope break near the edge of shoulder to a point 12 feet down the slope. When signs
are placed on fill slopes steeper than 6H:1V, locate the support at least 12 feet beyond the
slope break.

Use breakaway sign support features, when required, for signs located within the Design Clear
Zone and for signs located beyond this zone where there is a possibility they might be struck
by an errant vehicle. Breakaway features are not necessary on signposts located behind traffic
barriers. Install longitudinal barriers to shield signs without breakaway features within the
Design Clear Zone when no other options are available.

Sign bridges and cantilever sign structures have limited span lengths. Locate the vertical
components of these structures as far from the traveled way as possible and, where
appropriate, install traffic barriers (see Chapter 1610).

Do not locate signposts in the bottom of a ditch or where the posts will straddle the ditch. The
preferred location is beyond the ditch or on the ditch backslope (see the Standard Plans). In
high-fill areas where conditions require placement of a sign behind a traffic barrier, consider
adding embankment material to reduce the length of the sign supports.

1020.02(4) Sign Heights

For ground-mounted signs installed at the side of the road, provide a mounting height of at
least 7 feet, measured from the bottom of the sign to the edge of traveled way. Supplemental
plaques, when used, are mounted directly below the primary sign. At these locations, the
minimum mounting height of the plaque is 5 feet.

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Do not attach supplemental guide signs to the posts below the hinge mechanism or the saw
cut notch on multiple-post installations. The location of these hinges or saw cuts on the sign
supports are shown in the Standard Plans.

A minimum 7-foot vertical height from the bottom of the sign to the ground directly below the
sign is necessary for the breakaway features of the sign support to function properly when
struck by a vehicle. The minimum mounting height for new signs located behind longitudinal
barriers is 7 feet, measured from the bottom of the sign to the edge of traveled way. A lower
mounting height of 5 feet may be used when replacing a sign panel on an existing sign assembly
located behind the longitudinal barrier. The Standard Plans shows typical sign installations.

For ground-mounted signs installed on multiple posts that are a minimum of

12 feet from the edge of traveled way in cut sections, the minimum height clearance between
the sign and the ground for the post farther from the edge of traveled way is as follows:
 For slopes 2H:1V and steeper, the minimum height clearance is 2 feet.
 For slopes 3H:1V or flatter, the minimum height clearance is 7 feet.

Signs used to reserve parking for people with disabilities are installed at each designated parking
stall and are mounted 7 feet above the surface at the sign location.

1020.02(5) Foundations
Foundation details for timber and steel ground-mounted sign supports are shown in the
Standard Plans, which also contains foundation designs for truss-type sign bridges and
cantilever sign structures. Three designs, Types 1, 2, and 3, are shown for each structure.

An investigation of the foundation material is necessary to determine the appropriate

foundation design. Use the data obtained from the geotechnical report to select the
foundation type.
 The Type 1 foundation design uses a large concrete shaft and is the preferred
installation when the lateral bearing pressure of the soil is 2,500 psf or greater.
 The Type 2 foundation design has a large rectangular footing design and is an
alternative to the Type 1 foundation when the concrete shaft is not suitable.
 The Type 3 foundation design is used in poorer soil conditions where the lateral
bearing pressure of the soil is between 1,500 psf and 2,500 psf.

If a nonstandard foundation or monotube structure design is planned, forward the report to the
Headquarters (HQ) Bridge and Structures Office for use in developing a suitable foundation
design (see Chapter 610).

1020.02(6) Signposts
Ground-mounted signs are installed on either timber posts, laminated wood box posts, or steel
posts. The size and number of posts required for a sign installation are based on the height and
surface area of the sign, or signs, being supported. Use the information in Exhibits 1020-2, 1020-3,
and 1020-4 and the Standard Plans to determine the posts required for each installation.
Coordinate with the region Maintenance Office concerning signpost installation.

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Use steel posts with breakaway supports that are multidirectional if the support is likely to be
hit from more than one direction. For any wide flange multiple-steel post installations located
within the Design Clear Zone, the total weight of all the posts in a 7-foot-wide path is not to
exceed a combined post weight of 34 lbs/foot. Use the Wide Flange Beam Weights table in
Exhibit 1020-3 to determine wide flange steel post weights. If the proposed sign configuration
does not meet the weight criterion, relocate, resize, or provide barrier protection for the
proposed installation.

All signposts are to be designed to 90 mph wind loads. Design features of breakaway supports
are shown in the Standard Plans. Steel signposts commonly used are: Perforated Square Steel
Tube (PSST); Square Steel Tube (SST); Round Pipe (RP); and Wide Flange "H-Beam." Steel posts
with Type TP-A, TP-B, PL, PL-T, PL-U, AS, AP, SB-1, and SB-2 bases have multidirectional
breakaway features.

1020.03 Overhead Installation

Guidance on the use of overhead sign installations is provided in the MUTCD. Where possible,
mount overhead signs on grade separation structures rather than sign bridges or cantilever
supports.

Details for the construction of truss-type sign bridges and cantilever sign supports are shown
in the Standard Plans.

The HQ Bridge and Structures Office designs structure-mounted sign mountings, monotube sign
bridges, and monotube cantilever sign supports. For overhead sign installation designs, provide
sign dimensions, horizontal location in relation to the roadway, and location of the lighting
fixtures to facilitate design of the mounting components by the HQ Bridge and Structures Office.

1020.03(1) Illumination
The retroreflectivity of currently approved sign sheeting removes the need to provide
illumination for most sign installations.

The sign lights for existing illuminated overhead and ground-mounted signs can only be
de-energized and removed if the retroreflective sheeting is adequate for nighttime legibility,
or replace the existing sign with a new sign (see Exhibit 1020-1 for sheeting requirements).
A nighttime assessment of all nonilluminated overhead signs within the project limits is
required. Replace all signs that have inadequate retroreflectivity (contact the region Traffic
Office). In situations where a nonhighway light source interferes with a sign’s legibility, consider
relocating the sign or providing sign lights.

Flashing beacon signs are used to alert motorists of unusual or unexpected driving conditions
ahead. Sign lights are unnecessary on flashing beacon signs when appropriate sign sheeting,
full circle or tunnel signal head visors, and automatic dimmer devices are used.

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Chapter 1020 Signing

Exhibit 1020-1 Reflective Sheeting Requirements for Overhead Signs

Sheeting Type Sheeting Type

Overhead Sign Type
(Background) (Legend & Border)
EXIT ONLY guide sign IV* XI
Guide signs for left side exits IV XI
Other guide signs IV XI
Overhead street name signs IV XI
Regulatory signs IV n/a
Warning signs IX or XI n/a
*For Yellow Background Sheeting, use Type IX or XI Fluorescent Sheeting.

All other overhead signs are illuminated only when one of the following conditions is present:
 Sign visibility is less than 800 feet due to intervening sight obstructions such as highway
structures or roadside features.
 Signs directly adjacent to other overhead signs have sign lights.

1020.03(2) Vertical Clearance

The minimum vertical clearance from the roadway surface to the lowest point of an overhead sign
assembly is 17 feet 6 inches. The minimum vertical clearance from the roadway surface to the
lowest point of an overhead sign assembly without sign light(s) is 19 feet 6 inches. The maximum
clearance is 21 feet. Contact the HQ Traffic Office regarding signs under bridges and in tunnels.

1020.03(3) Horizontal Placement

Consider roadway geometrics and anticipated traffic characteristics when locating signs above
the lane(s) to which they apply. Install advance guide signs/exit direction signs that require an
EXIT ONLY and “down arrow” panel directly above the drop lanes. To reduce driver confusion
about which lane is being dropped, avoid locating a sign with an EXIT ONLY panel on a horizontal
curve.

1020.03(4) Service Walkways

Walkways are provided on structure-mounted signs, truss-type sign bridges, and truss-type
cantilever sign supports where roadway and traffic conditions prohibit normal sign maintenance
activities. Monotube sign bridges/cantilever sign supports normally do not have service walkways.

Vandalism of signs, particularly in the form of graffiti, can be a major problem in some areas.
Vandals sometimes use the service walkways and vandalize the signs. Maintenance costs for
cleaning or replacing the vandalized signs at these locations can exceed the benefit of providing
the service walkway.

1020.04 State Highway Route Numbers

For state routes, RCW 47.36.095 authorizes WSDOT to sign state highways using a system of
state route numbers assigned to eliminate duplication of numbers. This numbering system
follows the system employed by the federal government in the assignment of Interstate and
U.S. routes: odd numbers indicate general north-south routes and even numbers indicate
general east-west routes.

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1020.05 Mileposts
Milepost markers are a part of a statewide system for all state highways and are installed in
accordance with Executive Order E 1064, “State Route Mileposts,” and Chapter 2 of the Traffic
Manual.

1020.06 Guide Sign Plan

A preliminary guide sign plan is developed to identify existing and proposed guide signing on
state highways and is reviewed by the region Traffic Engineer. Preliminary guide signs for
Interstate routes are to be furnished to the HQ Traffic Office for review and concurrence. The
plan provides an easily understood graphic representation of the signing and its continuity to
motorist destinations, activities, and services. It is also used to identify deficiencies or poorly
defined routes of travel. A guide sign plan for safety and mobility Improvement projects is
desirable. When proposed highway work affects signing to a city or town, the guide sign plan
can be furnished to the official governing body for review and consideration. The guide sign
plan is reviewed and approved by the region Traffic Engineer.

1020.07 Documentation
Refer to Chapter 300 for design documentation requirements.

1020.08 References

1020.08(1) Federal/State Laws and Codes

23 Code of Federal Regulations (CFR) 655, Traffic Operations

WSDOT Executive Order E 1064, “State Route Mileposts,” WSDOT

Revised Code of Washington (RCW) 47.36, Traffic control devices

1020.08(2) Design Guidance

Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD), 2003 Edition,
FHWA, 2003, including the Washington State Modifications to the MUTCD, M 24-01, 2003

Plans Preparation Manual, M 22-31, WSDOT

Sign Fabrication Manual, M 55-05, WSDOT

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications),
M 41-10, WSDOT

Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic
Signals, 4th Edition, Washington DC, AASHTO, 2001

Traffic Manual, M 51-02, WSDOT

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 Chapter 1020 Signing

Exhibit 1020-2 Timber Posts

W W

Edge of traveled way

X=5 ft max X = 5 ft min
Edge of traveled way
to 18 ft max

Y/2
Y/2

Y
Y

0.6X

H1
H

H2
V
Z
V

B
A
A

D
B

D
C
Notes: D = Embedment depth
The following designs are not permitted when a sign is to H = Total post height
be located in or outside the Design Clear Zone in an area V = Vertical clearance from edge of traveled way
where it is likely to be struck by an errant vehicle: W = Distance from edge of traveled way to the
1. A sign with any post larger than 6x8 inches. centerline of the post nearest the roadway
2. A 2-post, 3-post, or 4-post sign that uses Design Example – Single Post
6x6-inch or larger posts and has two posts spaced Given:
less than 7 ft apart on center. Sign 3 ft wide, 3.5 ft high; a secondary sign 1.5 ft
wide, 2 ft high, mounted 3 inches (0.25 ft) below;
Table 1 Timber Post Selection
8-ft shoulder with 2% slope; 6H:1V embankment;
(X)(Y)(Z) (ft3)
Post Size D W = 15 ft; V = 5 ft
Number of Posts
(in) (ft) Solution:
1 2 3 4
X = 3 ft
4x4 60 115 175 235 3
Y = 3.5 + 2 + 0.25 = 5.75 ft
4x6 125 335 500 675 4
A = (0.02)(8) = 0.16
6x6 200 415 620 815 4
B = (W-8)/6 = (15-8)/6 = 1.17
6x8 330 695 1150 1515 5
Z = Y/2 + V + A + B
6 x 10 670 1355 2030 2700 6
8 x 10 835 1685 2515 3360 6 = (5.75/2) + 5 + 0.16 + 1.17 = 9.2 ft
6 x 12 985 2005 2965 3945 7 (X)(Y)(Z) = (3)(5.75)(9.2) = 158.7 ft3

Values shown are the maximum permitted. Since 159 ft3< 200 ft3, from Table 1, select 6x6 post
H = 9.2 + (5.75/2) + 4 = 16.1 ft
For timber grade requirements, see the Standard
Design Example – Double Post
Specifications.
Given:
Foundation depths are based on allowable lateral bearing
pressure in excess of 2500 psf. Sign 12 ft wide, 4 ft high; 10-ft shoulder with 2%
slope; 6H:1V embankment; W = 25 ft; V = 7 ft
If the value (X)(Y)(Z) amount exceeds the limit for 6x12
Solution:
post(s), use steel post(s) for sign installation.
X = 12 ft; Y = 4 ft
A = Vertical distance from edge of traveled
A = (0.02)(10) = 0.2
way to edge of shoulder
B = [(W-10) + (0.6X)]/6 = [(25-10) + (0.6)(12)]/6 = 3.7
B = Vertical distance from slope catch point
C = (0.6)(12)/6 = 1.2
to centerline of longest post
Z = Y/2 + V + A + B = 4/2+7 + 0.2 + 3.7 = 12.9 ft
C = Vertical distance between adjacent posts
(X)(Y)(Z) = (12)(4)(12.9) = 619 ft3
X & Y = Single sign or back-to-back signs: Overall
dimensions of the sign Since 619 ft3 < 695 ft3, select two 6x8 posts.
Multiple signs: Dimensions of the area within H2 = Y/2 + Z + D = 4/2 + 12.9 + 5 = 19.9 ft
the perimeter of a rectangle enclosing the H1 = H2-C = 19.9-1.2 = 18.7 ft
extremities of the sign
Note: 6x6 and larger posts require 7-ft spacing. Sign
Z = Height from ground line to midheight of sign
at the centerline of the longest post may be installed within the Design Clear Zone.

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Signing Chapter 1020
Notes:
Exhibit 1020-3 Wide Flange Steel Posts
 Values shown in Table 1 are the maximum permitted.
X & Y = Single sign or back-to-back signs: Overall  A single-wide flange post installation is not allowed.
dimensions of the sign  Consider using one of the following: perforated
Multiple signs: Dimensions of the area within square steel tube posts, solid steel tube posts, or
the perimeter of a rectangle enclosing the round steel posts.
extremities of the signs  For post selection for other than wide flange beam
Z = Height from the base connection (2½ inches supports and a single-post assembly, see the
above the post foundation for wide flange Standard Plans. To determine post sizes for these
beams) to the midheight of the sign at the types of posts, use the wind load charts at:
centerline of the longest post  www.wsdot.wa.gov/design/traffic/signing
H = Post length
(See the Standard Plans for additional information.)
V = Vertical clearance from the edge of traveled way
W = Distance from the edge of traveled way to

Edge of traveled way

the centerline of the longest post nearest W
the roadway X = 18 ft max
Design Example – Steel Post Selection

Y/2
Given:

Y
Sign 22 ft wide, 12 ft high; 10 ft shoulder with 2% slope;
3H:1V embankment; W = 32 ft; V = 7ft.
0.2X 0.6X
Solution:

H2
H1

Z
X = 22
Y = 12 V
A = (0.02)(10) = 0.2
B = [(W-10) + (0.7)(X/3)] = [(32-10) + (0.7x22)]/3 = 12.5

B
A

C = (0.35)(22)/3 = 2.6
Z = Y/2 + V + A + B-0.21
= 12/2 + 7 + 0.2 + 12.5-0.21 = 25.5 ft
(X)(Y)(Z) = (22)(12)(25.5) = 6729 ft3
Since 6729 ft3 < 9480 ft3, select three W10x26 (ASTM
A36) or W10x22 (ASTM A992) (see the Standard Plans)
Edge of traveled way

H3 = 12/2 + 25.5 = 31.5 ft W

H2 = H3-C = 31.5-2.6 = 28.9 ft X = 24 ft max
H1 = H2-C = 28.9-2.6 = 26.3 ft

Y/2
Table 1 Wide Flange Steel Post Selection
Y

Wide Flange Beam

Post Size (X)(Y)(Z) (ft3)
0.15X 0.35X 0.35X
Number of Posts
H3

ASTM A992 ASTM A36 2 3

Z
V

H1

H2

W6x9 W6x12 1570 2355

W6x12 W6x16 2340 3510
W8x18 W8x21 4120 6180
W10x22 W10x26 6320 9480
B
A

W12x26 W12x30 8700 ---

C

Table 2 Wide Flange Beam Weights

Beam Size Weight lbs/ft Beam Size Weight lbs/ft
W6x9 9 W8x21 21
W6x12 12 W10x22 22
W6x16 16 W10x26 26
W8x18 18 W12x26 26
W10x30 30

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Exhibit 1020-4 Laminated Wood Box Posts

W

Edge of traveled way

X = 24 ft max

Y/2
Y
0.6X

H1

H2
V

B
A

D
X & Y = Single sign or back-to-back signs: C
Table 1 Laminated Wood Box Post Selection
Overall dimensions of the sign Post Type Size (in) Z (ft) (X)(Y)(Z) ft3
Multiple signs: Dimensions of the area within M 7 7/8 x 7 7/8 15 < Z< 26 1329
the perimeter of a rectangle enclosing the M 7 7/8 x 7 7/8 Z < 15 1661
extremities of the signs L 7 7/8 x 14 7/8 15 < Z < 26 3502
L 7 7/8 x 14 7/8 Z < 15 4378
Z = Height from ground line to the midheight of
the sign at the centerline of the longest post Table 2 Embedment Depth (D)
D = Embedment depth Sign Area ft 2
H = Post length Z (ft) Up to 51 to 101 to 151 to 201 to 251 to
V = Vertical clearance from edge of traveled way 50 100 150 200 250 290
9 to 12 6 6 7 8 9 10
W = Distance from edge of traveled way to the 13 to 15 6 6 7.5 9 10
centerline of the post nearest the roadway 16 to 18 7 7.5 9
(see the Standard Plans) 19 to 22 7 8 10
23 to 26 7.5 8.5
Design Example – M Post Selection
Design Example – L Post Selection
Given:
Two-post assembly sign 16 ft wide, 6 ft high; 10 ft Given:
shoulder with 2% slope; 6H:1V embankment; W = 25 Two-post assembly sign 18 ft wide, 8 ft high;10 ft
ft; V = 7 ft shoulder with 2% slope; 6H:1V embankment W = 25
Solution: ft; V = 7 ft
X = 16 Solution:
Y =6 X = 18
A = (0.02)(10) = 0.2 Y=8
B = [(W-10) + 0.6X]/6 A = (0.02)(10) = 0.2
= [(25-10) + (0.6)(16)]/6 = 4.1 B = [(W-10) + (0.6X)]/6 = [(25-10) + (0.6)(18)]/6 = 4.3
C = (0.6X)/6 = (0.6)(16)/6 = 1.6 C = 0.6X/6 = (0.618)/6 = 1.8
Z = Y/2 + V + A + B = 6/2 + 7 + 0.2+4.1 = 14.3 ft Z = Y/2 + V + A + B = 8/2 + 7 + 0.2 + 4.3 = 15.5 ft
(X)(Y)(Z) = (16)(6)(14.3) = 1373 ft3 (X)(Y)(Z) = (18)(8)(15.5) = 2232 ft3
Since 1373 ft3 < 1661 ft3, select a post type M from Since 2232 ft3 < 3502 ft3, select a post type L from
Table 1. Table 1.
H2 = Y/2 + Z + D = 6/2 + 14.3 + 6 = 23.3 ft H2 = Y/2 + Z + D = 8/2 + 15.5 + 9 = 28.5 ft
H1 = H2-C = 23.3-1.6 = 21.7 ft H1 = H2-C = 28.5 – 1.8 = 26.7 ft

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Chapter 1030 Delineation
1030.01 General
1030.02 Definitions
1030.03 Pavement Markings
1030.04 Guideposts
1030.05 Barrier Delineation
1030.06 Object Markers
1030.07 Documentation
1030.08 References

1030.01 General
The primary function of delineation is to provide the visual information needed by a driver to
operate a vehicle in a variety of situations. Delineation includes the marking of highways with
painted or more durable pavement marking lines and symbols, guideposts, and other devices
such as curbs. These devices can use retroreflectance, which is the reflecting of light from a
vehicle’s headlights back to the driver, to enhance an object’s visibility at nighttime.

Delineation is a required design element (see Chapter 1105) on most projects. A decision to
omit delineation is possible if the existing delineation is unaffected by construction and a safety
performance evaluation (see Chapter 321) clearly shows that delineation is not a contributing
factor to crashes. The Washington State Department of Transportation (WSDOT) uses the latest
edition of the Manual on Uniform Traffic Control Devises (MUTCD) as a guide for the design,
location, and application of delineation.

Consult with the region Traffic Office early in the design process to ensure the proposed
delineation is compatible with current WSDOT policy and guidance regarding types of markings
and material selection.

1030.02 Definitions
The following terms are defined in the Design Manual Glossary:

Delineation; extrude; mcd/m2/lux; pavement marking; pavement marking beads; pavement

marking durability; retroreflection, coefficient of (RL); traffic paint; and wet film thickness.

1030.03 Pavement Markings

1030.03(1) Pavement Marking Types

Pavement markings have specific functions: they guide the movement of traffic and they
promote increased safety performance. In some cases, they are used to supplement the
messages of other traffic control devices. In other cases, markings are the only way to convey a
message without distracting the driver. Pavement markings are intended to provide adequate
performance year round. Guidelines for the application of various pavement markings are
provided in the Standard Plans and the MUTCD.

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1030.03(1)(a) Longitudinal Pavement Markings

Longitudinal pavement markings define the boundary between opposing traffic flows, and they
identify the edges of traveled way, multiple traffic lanes, turn lanes, and special-use lanes. The
Standard Plans shows the dimensions of longitudinal pavement markings. Longitudinal
pavement markings are as follows:

barrier centerline A very wide—18 inches minimum, usually 20 inches: five 4 inch lines—solid
yellow line or a combination of two single 4-inch solid yellow lines with yellow crosshatching
between the lines, with a total width not less than 18 inches, used to separate opposing traffic
movements where all movements over the line are prohibited. Barrier centerline locations
require the approval of the region Traffic Engineer and Access Engineer.

centerline A broken yellow line used to separate lanes of traffic moving in opposite directions,
where passing in the opposing lane is allowed.

dotted extension line A broken white or yellow line that is an extension of an edge line or
centerline used at exit ramps, intersections on horizontal curves, multiple turn lanes, and other
locations where the direction of travel for through or turning traffic is unclear.

double centerline Two parallel solid yellow lines used to separate lanes of traffic moving in
opposite directions where passing in the opposing lane is prohibited.

double lane line Two solid white lines used to separate lanes of traffic moving in the same
direction where crossing the lane line marking is prohibited.

double wide lane line Two solid wide white lines used to separate a concurrent preferential
lane of traffic where crossing is prohibited.

drop lane line A wide broken white line used in advance of a wide line to delineate a lane that
ends at an off-ramp or intersection.

edge line A solid white or yellow line used to define the outer edges of the traveled way. Edge
lines are not required where curbs or sidewalks are 4 feet or less from the traveled way.

lane line A broken white line used to separate lanes of traffic moving in the same direction.

no-pass line A solid yellow line used in conjunction with a centerline where passing in the
opposing lane is prohibited.

reversible lane line Two broken yellow lines used to delineate a lane where traffic direction is
periodically reversed.

solid lane line A solid white line used to separate lanes of traffic moving in the same direction
where crossing the lane line marking is discouraged.

two-way left-turn centerline Two yellow lines, one solid and one broken, used to delineate
each side of a two-way left-turn lane.

wide broken lane line A wide broken white line used to designate a portion of a high-
occupancy vehicle (HOV) lane located on a divided highway where general-purpose vehicles may
enter to make an exit.

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wide dotted lane line A wide broken white line used to designate a portion of a high-
occupancy vehicle (HOV), or business access and transit (BAT) lane located on an arterial
highway where general-purpose vehicles may enter to make a turn at an intersection.

wide lane line A wide solid white line used to separate lanes of traffic moving in the same
direction, at ramp connections, storage lanes at intersections, and high-occupancy vehicle (HOV)
lanes, or at business access and transit (BAT) lanes, bike lanes, and other preferential lanes
where crossing is discouraged.

See MUTCD Chapter 3B for further information for these markings.

1030.03(1)(b) Transverse Pavement Markings

Transverse pavement markings define pedestrian crossings and vehicle stopping points at
intersections. They are also used to warn motorists of approaching conditions, required
vehicular maneuvers, or lane usage. See the Standard Plans for details of these pavement
markings. Typical transverse pavement markings are as follows:

access parking space symbol A white marking used to designate parking stalls provided for
motorists with disabilities. The marking may have an optional blue background and white
border.

aerial surveillance marker White markings used at one-mile and one-half-mile intervals on
sections of highways where the State Patrol uses airplanes to enforce speed limits.

bicycle lane symbol A white marking consisting of a symbol of a bicyclist and an arrow used in
a marked bike lane. The bicycle lane symbol is to be placed immediately after an intersection
and at other locations as needed (see the MUTCD). Typical spacing is 500 feet, with a maximum
distance of 1,500 feet.

crosswalk line A series of parallel solid white lines used to define a pedestrian crossing.

drainage marking A white line used to denote the location of a catch basin, grate inlet, or
other drainage feature in the shoulder of a roadway.

HOV symbol A white diamond marking used for high-occupancy vehicle lanes. The spacing of
the markings is an engineering judgment based on the conditions of use. Typical spacing is 1000
feet for divided highways and 500 feet for arterial highways.

railroad crossing symbol A white marking used in advance of a railroad crossing where grade
crossing signals or gates are located or where the posted speed of the highway is 40 mph or
higher.

stop line A solid white line used to indicate the stopping point at an intersection or railroad
crossing.

traffic arrow A white marking used in storage lanes and two-way left-turn lanes to denote the
direction of turning movement. Arrows are also used at ramp terminals and intersections on
divided highways to discourage wrong-way movements.

traffic letters White markings forming word messages, such as “ONLY,” used in conjunction
with a traffic arrow at drop-lane situations. Traffic letters are not required for left- and right-
turn storage lanes where the intended use of the lane is obvious.

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wide line A wide solid line used for traffic islands, hash marks, chevrons, and other
applications. A wide line used in conjunction with a centerline marking shall be yellow. A wide
line used in conjunction with a lane line or right edge line marking shall be white.

Yield line markings A series of white triangular markings indicating that the lane yields.

1030.03(2) Pavement Marking Materials

Pavement markings are applied using various materials. These materials are divided into two
categories: paint and plastic. When selecting the pavement marking material to use in a project,
consider the initial cost of the material and its durability; the location; the traffic conditions; the
snow and ice removal practices of the particular maintenance area; and the region’s ability to
maintain the markings.

Both painted and plastic pavement markings can accomplish the goal of providing a visible
(daytime) and retroreflective (nighttime) pavement marking at the completion of a contract. The
difference between the two marking materials is the projected durability of the markings. Paint
used on sections of highway subjected to high traffic volumes and/or snow-removal operations
might have a durability of only two to three months. Maintenance crews cannot restripe a
highway during winter months; therefore, if a painted marking wears out prematurely, the
highway will not have a stripe until maintenance crews can restripe in April or May. When these
conditions are encountered in a highway project, consider a more durable plastic marking
material and application type that will provide the desired durability for the marking.

Check with your region Traffic Office for any specific pavement marking policy. For the
recommended pavement marking material for different highway types and snow-removal
practices, see Exhibit 1030-1. Consult with the region’s Traffic and Maintenance offices to select
the best material for the project.

1030.03(2)(a) Paint

Paint is the most common pavement marking material. It is relatively easy to apply and dries
quickly (30–90 seconds in warm, dry weather) after application. This allows the application to be
a moving operation, which minimizes traffic control costs and delays to the roadway users. On
construction contracts, paint is applied with two coats: the first coat is 10 mils thick, followed by
a second coat 15 mils thick. The disadvantage of using paint as a pavement marking material is
its limited durability when subjected to traffic abrasion, sanding, or snow-removal activities.
Specify paint only where it will have a durability that will provide a retroreflective stripe until
maintenance crews can repaint the line and extend its usefulness until the next repainting.

Paint is one of two material types dependent upon the solids carrier: solvent or water. The
designer is encouraged to specify waterborne paint. Solvent paint is subject to a monetary
penalty because it contains a high level of volatile organic compounds (VOCs). There is an
Environmental Protection Agency (EPA) Clean Air Act penalty assessed on solvent paint that is
passed on to those who purchase solvent paint in quantity.

Durable waterborne paint or high-build waterborne paint is formulated to allow application

thicknesses greater than 15 mils. It is more durable than standard waterborne paint and
provides additional service life. The additional thickness permits the use of larger beads that
enhance wet night retroreflectivity.

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Low-temperature waterborne paint is intended to extend the paint season later into the fall,
although it may also be used earlier in the spring. The paint is formulated for application
temperatures of 35° Fahrenheit and rising, though durability can be affected when applied
during conditions where standard waterborne paint could have been used.

1030.03(2)(b) Plastic

Plastic markings have a higher installation cost than paint. They can, however, be a more cost-
effective measure than paint because of their longer service life. Plastic marking materials may
provide a year-round retroreflective pavement marking, while paint may not last until the next
restriping. Plastic marking materials currently listed in the Standard Specifications include the
following:
1. Type A: Liquid Hot Applied Thermoplastic

Thermoplastic material consists of resins and filler materials in solid form at room
temperature. The material is heated to a semiliquid, molten state (400° Fahrenheit) and is
then applied to the roadway by spray or extrusion methods. This material can be used for
both transverse and longitudinal line applications. Special equipment is required for both
the initial application and subsequent maintenance renewal. Sprayed material can be
applied at a thickness of 30 mils and dries in 30 to 60 seconds. The durability of material
applied in this manner is slightly longer than that of paint. Extruded material is applied at a
thickness of 125 mils and has a drying time of 15 minutes. This material can be applied as a
flat line or applied with ridges or profiles (bumps) that enhance wet night visibility. These
profiles produce a rumble effect similar to raised pavement markers when a vehicle crosses
over the marking. (Profiles come in the shape of a raised bar at set intervals and are formed
simultaneously with the extruded baseline.)

2. Type B: Preformed Fused Thermoplastic

This material consists of a mixture of pigment, fillers, resins, and beads that are factory
produced in sheet form, 125 mils thick. The material is applied by heating (drying) the
pavement and top heating the material. The heating process fuses the preformed
thermoplastic material to the pavement surface. These materials, which are used for
transverse markings, are available in white, red, blue, and other colors.

3. Type C: Cold Applied Preformed Tape

Preformed tape is composed of thermoplastic or other materials that are fabricated under
factory conditions. After curing, the material is cut to size and shipped to the work site in
rolls or in flat pieces. The material is then applied to the roadway with an adhesive on the
underside of the tape. Preformed tape is available in 60, 90, or 125 mils (WSDOT does not
currently specify 125 mil tape.) The most durable application of preformed tape is achieved
when the tape is either inlaid (rolled) into hot asphalt with the top of the tape flush with the
surface of the pavement, or placed in a groove cut into the pavement surface with the top
of the tape slightly below the surface of the pavement.

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ASTM has classified preformed tape into two categories: Type 1 and Type 2. Type 1 tape has
a profiled surface and a requirement to have a retroreflectivity of over 500 mcd/m2/lux.
Type 1 tape has proven to be very durable. It is used on high-volume, high-speed highways.
Type 2 tape has a flat surface and a requirement to have a retroreflectivity of over
250 mcd/ m2/lux. Field tests show that Type 2 tape has a shorter durability than Type 1
tape.

4. Type D: Liquid Cold Applied Methyl Methacrylate (MMA)

Methyl methacrylate can be applied by either spraying or extrusion. Sprayed applications

can be one or two coats, 30 to 45 mils thick. Extruded applications are 90 mils thick for
asphalt concrete pavement or Portland cement concrete pavement, or 120 mils thick for
open-graded asphalt pavement. MMA can also be extruded using specialized equipment to
produce a textured line 150 mils thick. The material is not heated and can be applied within
an approximate temperature range of 40° to 105° Fahrenheit, provided the pavement
surface is dry. The material can be used for both transverse and longitudinal applications.
The material can also be applied with profiles (bumps) that slightly enhance wet night
retroreflectivity. The profiles also produce a rumble effect similar to raised pavement
markers.

1030.03(2)(c) Beads

Glass beads are small glass spheres used in highway markings to provide the necessary
retroreflectivity. The beads are dropped onto the wet marking material immediately after it is
applied (drop-on beads), or premixed into the wet marking material.

Proper installation of glass beads is critical to achieving good pavement marking

retroreflectivity. Each glass bead works like a light-focusing lens, reflecting light back to the
driver. Glass beads are embedded into the pavement marking material; for optimum
performance, the bead is embedded between 55% and 60% of its diameter.

Large glass and composite beads are effective when roads are wet. Large glass or composite
beads are not appropriate for standard mil paint as the paint is too thin to properly embed the
large glass or composite beads; therefore, WSDOT specifies small glass or composite beads for
such paint applications. The use of large glass or composite beads is limited to high-build
waterborne paint and other materials with a thickness of at least 22 mils.

1030.03(3) Pavement Marking Application Types

There are five application types used for pavement markings. Most pavement marking
applications are applied directly to the pavement surface. In steel bit snow plowing areas, the
pavement markings may be inlaid or grooved to protect the markings.

Because they are higher than the surrounding pavement surface, pavement markings are
subject to rapid wear caused by traffic and snowplows. As they wear, they lose visibility and
retroreflectivity, particularly in wet weather. Wear on the stripes can be greatly reduced and
their durability considerably increased by placing them in a shallow groove in the surface of the
pavement.

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1030.03(3)(a) Application Types

The five application types for pavement markings are:

1. Flat Lines

Flat lines are pavement marking lines with a flat surface.

2. Profiled Marking

A profiled pavement marking consists of a baseline thickness and a profiled thickness, which
is a portion of the pavement marking line that is applied at a greater thickness than the
baseline thickness. Profiles are applied using the extruded method in the same application
as the baseline. The profiles may be slightly rounded if the minimum profile thickness is
provided for the entire length of the profile. (See the Standard Plans for the construction
details.)

3. Embossed Plastic Line

Embossed plastic lines consist of a flat line with transverse grooves. An embossed plastic
line may also have profiles. (See the Standard Plans for the construction details.)

4. Inlaid Plastic Line

Inlaid plastic line is constructed by rolling Type C tape into hot mix asphalt (HMA) with the
finish roller. This application is used infrequently by WSDOT and is not in the Standard
Specifications.

5. Grooved Plastic Line

Grooved plastic line is constructed by cutting a groove into the pavement surface and
spraying, extruding, or gluing pavement marking material into the groove. The groove depth
is dependent upon the material used, the pavement surface, and the location. The groove is
typically in the range of 20 to 250 mils deep and 4 inches wide. Coordinate with the region
Traffic Office on the use and dimensions of grooved plastic line marking.

1030.03(4) Raised Pavement Markers

Raised pavement markers (RPMs) are installed as positioning guides with long line pavement
markings. They can also be installed as a complete substitution for certain long line markings.
RPMs have a durability of two years, and they provide good wet night visibility and a rumble
effect. RPMs are made from plastic materials and are available in three different types:
 Type 1 markers are 4 inches in diameter, ¾ inch high, and non-reflectorized.
 Type 2 markers are 4 inches wide, 4 inches long, ¾ inch high, and reflectorized.
 Type 3 markers are 6, 8, 10, or 12 inches wide, 4 inches long, ¾ inch high, and
non-reflectorized.

Type 2 RPMs are not used as a substitute for right edge lines. They may be used to supplement
the right edge line markings at lane reductions, at sections with reduced lane widths such as

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Delineation Chapter 1030

narrow structures, and at the gore of exit ramps. All other applications supplementing right
edge line markings require the approval of the region Traffic Engineer.

Red-backed RPMs are not desired and thus are only used at the discretion of the Region Traffic
Engineer for specific locations. Research regarding their effectiveness for addressing wrong-way
driving has been inconclusive to date.

Type 3 RPMs are used in locations where additional emphasis is desired, including vehicle
separations and islands. Obtain approval by the region Traffic Engineer for all installations of
Type 3 RPMs. Retain approval in the Design Documentation Package.

Reflectorized RPMs are not required for centerline and lane line applications in continuously
illuminated sections of highway. However, if illumination policies (see Chapter 1040) affect a
section of limited access roadway, coordinate with the region Traffic Engineer for RPM
placement details. If reflectorized RPMs are used at an intersection within an illuminated
section, they are also to be used throughout that section.

For raised pavement marker application details, see the Standard Plans.

1030.03(5) Recessed Raised Pavement Markers

Recessed raised pavement markers (RRPMs) are raised pavement markers (RPMs) installed in a
groove ground into the pavement in accordance with the Standard Plans. RRPMs provide
guidance similar to RPMs in ice chisel and steel blade snow-removal areas. RRPMs can also be
used in rubber or Cooper-style blade snow-removal areas in accordance with region policy.

Designers should be aware that the performance of RRPMs can be compromised, especially on
curves, because the groove can block motorists’ view of the markers. Also, the groove for
RRPMs installed on flat grades can fill with water during rain events and cause the RRPM to be
non-reflective.

RRPMs, when specified, are installed at the locations shown in the Standard Plans for Type 2W
RPMs on multilane one-way roadways and Type 2YY RPMs on two-lane two-way roadways.

Do not recess side-to-side RPMs on wide dotted lane lines.

For recessed pavement marker application details, see the Standard Plans.

1030.04 Guideposts

1030.04(1) General
Guideposts are retroreflective devices installed at the side of the roadway to indicate alignment.
They are guidance devices rather than warning devices. Guideposts are used as an aid to
nighttime driving primarily on horizontal curves; multilane divided highways; ramps; tangent
sections where they can be justified due to snow, fog, or other reduced-visibility conditions; and
at intersections without illumination.
1030.04(1)(a) Types of Guideposts

The retroreflective device may be mounted on either a white or brown post. The types of
guideposts and their application are as follows:

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1. Type W

Type W guideposts have silver-white reflective sheeting, are facing traffic, and are used on
the right side of divided highways, ramps, right-hand acceleration and deceleration lanes,
intersections, and ramp terminals.

2. Type WW

Type WW guideposts have silver-white reflective sheeting on both sides and are used on the
outside of horizontal curves on two-way undivided highways.

3. Type Y

Type Y guideposts have yellow reflective sheeting, are facing traffic, and are used on the left
side of ramps, left-hand acceleration and deceleration lanes, ramp terminals, intersections
on divided highways, median crossovers, and horizontal curves on divided highways.

4. Type YY

Type YY guideposts have yellow reflective sheeting on both sides and are used in the median
on divided highways.

5. Type IC1

Type IC1 guideposts have silver-white reflective sheeting on both sides and an additional
silver-white piece of reflective sheeting below the standard silver-white sheeting on the side
facing traffic. They are used at intersections of undivided highways without illumination.

6. Type IC2

Type IC2 guideposts have silver-white reflective sheeting on both sides and an additional
silver-white piece of reflective sheeting below the standard silver-white reflective sheeting
on the back side. They are used at intersections of undivided highways without illumination.

1030.04(2) Placement and Spacing

Guideposts are placed not less than 2 feet and not more than 8 feet outside the outer edge of
the shoulder. Place guideposts at a constant distance from the edge of the roadway. When an
obstruction intrudes into this space, position the guideposts to smoothly transition to the inside
of the obstruction. Guideposts are not required along continuously illuminated divided or
undivided highways. (See Exhibit 1030-2 for guidepost placement requirements and the
Standard Plans for information on the different types and placement of guideposts.)

1030.05 Barrier Delineation

Traffic barriers are delineated where guideposts are required, such as bridge approaches,
ramps, and other locations on unilluminated roadways (see Exhibit 1030-2). At these locations,
the barrier delineation has the same spacing as that of guideposts. Barrier delineation is also
required when the traffic barrier is 4 feet or less from the traveled way. Use a delineator spacing
of no more than 40 feet at these locations.

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Beam guardrail can be delineated by either mounting flexible guideposts behind the rail or by
attaching shorter flexible guideposts to the wood guardrail posts.

Concrete barrier can be delineated by placing retroreflective devices on the face of the barrier
about 6 inches down from the top. Consider mounting these devices on the top of the barrier at
locations where mud or snow accumulates against the face of the barrier.

1030.06 Object Markers

Object markers are used to mark obstructions within or adjacent to the roadway. The MUTCD
details three types of object markers. The Type 3 object marker with yellow and black sloping
stripes is the most commonly used object marker.

The MUTCD contains criteria for the use of object markers to mark objects in and/or adjacent to
the roadway. Follow these criteria in project design.

The terminal ends of impact attenuators are delineated with modified Type 3 object markers.
These are the impact attenuator markers in the Sign Fabrication Manual. When the impact
attenuator is used in a roadside condition, the marker with diagonal stripes pointing downward
toward the roadway is used. When the attenuator is used in a gore where traffic will pass on
either side, the marker with chevron stripes is used.

End of Roadway markers are similar to Type 1 object markers and are detailed in the MUTCD.
They are used to alert users about the end of the roadway. Follow the MUTCD criteria in project
design.

1030.07 Documentation
Refer to Chapter 300 for design documentation requirements.

1030.08 References

1030.08(1) Federal/State Laws and Codes

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

1030.08(2) Design Guidance

Roadway Delineation Practices Handbook, FHWA report, Washington, DC, 1994

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications),
M 41-10, WSDOT

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Exhibit 1030-1 Pavement Marking Material Guide – Consult Region Striping Policy

Marking Type [3]

Roadway
Classification Transverse
Centerlines [5] Lane Lines [5] Edge Lines Wide Lines
Markings
Ice Chisel Snow Removal Areas
Interstate N.A. Grooved Plastic [1] Paint Paint Paint
Paint & RRPMs[4] or
Major Arterial Paint Paint Paint Paint
Plastic[2] & RRPMs[4]
Minor Arterial Paint Paint Paint Paint Paint
Collector Paint Paint Paint Paint Paint
Steel Blade Snow Removal Areas
Interstate-Urban N.A. Plastic [2] Paint or Plastic[2] Paint or Plastic[2] Paint or Plastic[2]
Interstate-Rural N.A. Paint Paint or Plastic[2] Paint or Plastic[2] Paint or Plastic[2]
Paint & RRPMs[4] or
Major Arterial Paint Paint or Plastic[2] Paint or Plastic[2] Paint or Plastic[2]
Plastic[2] & RRPMs[4]
Minor Arterial Paint Paint Paint Paint or Plastic[2] Paint or Plastic[2]
Collector Paint Paint Paint Paint or Plastic[2] Paint or Plastic[2]
Rubber Blade Snow Removal Areas
PMMA [6] only or
Interstate-Urban N/A Paint or Plastic[2] Plastic FMMA [7]
PMMA & RPMs
PMMA [6] only or
Interstate-Rural N/A Paint Plastic [2] FMMA [7]
PMMA & RPMs
Paint & RPMs or
Major Arterial Paint Plastic [2] Plastic [2]
Plastic [2] & RPMs
Minor Arterial Paint & RPMs Paint & RPMs Paint Plastic [2] Plastic [2]
Collector Paint & RPMs Paint Paint Plastic [2] Plastic [2]
Notes:
[1] Grooved Plastic is a line constructed by cutting a groove into the pavement surface and spraying, extruding, or
gluing pavement marking material into the groove.
[2] Plastic refers to methyl methacrylate (MMA), thermoplastic, or preformed tape.
[3] For RPM substitute applications and RPM applications supplementing paint or plastic, see the Standard Plans,
Section M.
[4] RRPMs refer to RPMs installed in a groove ground into the pavement. RRPMs are identified as “Recessed
Pavement Markers” in the Standard Specifications and the Standard Plans.
[5] Type 2 RPMs are not required with painted or plastic centerline or lane line in continuously illuminated
sections.
[6] PMMA refers to profiled methyl methacrylate.
[7] FMMA refers to flat methyl methacrylate.

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Exhibit 1030-2 Guidepost Placement

Guideposts on
Location Guideposts on Tangents [1][3]
Horizontal curves [1][3]
Divided Highways With Continuous Illumination
Main Line None None
Bridge Approaches None None
Intersections None None
Lane Reductions [4] [4]
Median Crossovers None None
Ramps [4] [4]
Divided Highways Without Continuous Illumination
Main Line with RPMs None [4]
Main Line without RPMs Right Side Only (0.10 mile spacing) [4]
Bridge Approaches [4] [4]
Intersections [4] [4]
Lane Reductions [4] [4]
Median Crossovers [4] [4]
Ramps [4] [4]
Undivided Highways With Continuous Illumination
Main Line None None
Bridge Approaches None None
Intersections None None
Lane Reductions [4] [4]
Undivided Highways Without Continuous Illumination
Main Line [2] Standard Plans, Section M[2]
Bridge Approaches [4] [4]
Intersections with Illumination None None
Intersections without Illumination [4] [4]
Lane Reductions [4] [4]

Notes:

[1] For lateral placement of guideposts, see the Standard Plans, Section M.

[2] Installation of guideposts on tangents and on the inside of horizontal curves is allowed at locations
approved by the region Traffic Engineer.

[3] Barrier delineation is required when the traffic barrier is 4 feet or less from the traveled way. Use
delineator spacing of 40 feet or less.

[4] Standard Plans, Section M

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Chapter 1040 Illumination
1040.01 General
1040.02 Definitions
1040.03 Design Considerations
1040.04 Required Illumination
1040.05 Additional Illumination
1040.06 Design Criteria
1040.07 Documentation
1040.08 References

1040.01 General
Illumination is provided along highways, in parking lots, and at other facilities to enhance the
visual perception of conditions or features that require additional motorist, cyclist, or pedestrian
alertness during the hours of darkness.

The Washington State Department of Transportation (WSDOT) is responsible for illumination on

state highways and crossroads (WAC 468-18-040 and WAC 468-18-050) with partial limited
access control, modified limited access control, or full limited access control, regardless of the
location. WSDOT is responsible (WAC 468-18-050) for illumination on state highways and
crossroads with managed access control located outside the corporate limits of cities. Cities are
responsible for illumination on managed access state highways within their corporate limits.

For the definitions of limited access control and managed access control, see Chapter 520. For a
listing (by milepost) of the limited access or managed access status of all state highways, refer to
the Access Control Tracking System Limited Access and Managed Access Master Plan, under the
“More Information” heading:  www.wsdot.wa.gov/design/accessandhearings. For further
information, refer to the WSDOT/Association of Washington Cities agreement “City Streets as
Part of State Highways”:  www.wsdot.wa.gov/localprograms/lag/construction.htm

1040.02 Definitions
The following terms are defined in the Glossary: adaptive lighting system, average light level,
complex ramp alignment and grade, continuous load, footcandle (fc), lamp lumens, light
emitting diode(LED), long tunnel, lumen, luminaire, luminance, luminous flux, maximum
uniformity ratio, maximum veiling luminance ratio, minimum average light level, minimum light
level, mounting height – luminaire, multimodal connection, negative illumination, nighttime,
pedestrian crossing, pole height (H1), positive illumination, roadway luminance, security lighting,
short tunnel, SIgnal Maintenance Management System (SIMMS), slip base, spacing, transit flyer
stop, transit stop, uniformity ratio, and veiling luminance.

1040.03 Design Considerations

An illumination system is built from many separate components. The simplest illumination
system contains the following:
 A power feed from the local utility company.

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 An electrical service cabinet containing a photocell and circuit breaker for each
illumination circuit.
 Runs of conduit with associated junction boxes leading to each luminaire.
 Conductors routed from the service cabinet breaker to each luminaire.
 A concrete light standard foundation.
 A light standard with a slip base or a fixed base.
 A luminaire (light) over or near the roadway edge line.

There are design considerations that need to be addressed when performing even the most
minimal work on an existing illumination system. An existing electrical system is acceptable for
use under the design requirements and National Electric Code (NEC) rules that were in effect at
the time of installation. When modifying an existing electrical service or transformer, the
designer is responsible for bringing the whole system up to current NEC design standards.
Retrofitting an existing fixed base light standard with a slip base feature requires the installation
of quick disconnect fittings and fuses in the circuit, at the luminaire only. The existing conductor
configuration for a fixed base luminaire is not acceptable for use on a breakaway (slip base)
installation. Existing conductors and components that no longer meet current NEC requirements
are to be replaced and the whole circuit is to be designed to current standards. This may mean
replacing the whole circuit back to the nearest overcurrent protection device (circuit breaker).
Address the following when modifying an existing illumination system:
 Whether the existing circuit is in compliance with current NEC standards (deficient
electrical component).
 Whether existing luminaire system components, such as conductors, conduit, junction
boxes, foundation, and pole comply with current standards.
 Whether conductors meet NEC requirements for temperature rating (deficient
electrical component).
 Conductor material: aluminum conductors or copper conductors (deficient electrical
component).
 Whether the existing bonding and grounding system is adequate: cabinets, poles,
junction boxes, including lids, and other appurtenances are bonded and grounded per
NEC requirements.
 The condition and adequacy of the existing conduit running between the luminaire and
the nearest junction box (deficient electrical component).
 The condition of the junction box next to the luminaire (deficient electrical
component).
 The suitability of the existing foundation to meet current design requirements.
 The suitability of the location to meet current design standards for illumination.
 The location and bolt pattern of the existing foundation to meet current design
standards.
 The design life remaining for the existing light standard (deficient electrical
component).
 The condition of the existing light standard (deficient electrical component).

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Chapter 1040 Illumination

 Maintenance personnel assessment of the electrical safety of the installation.

Involve appropriate Headquarters (HQ) and region Traffic Office design personnel early in the
process. Ensure potential system deficiencies are reflected in the estimate of work.

Maintain required illumination during all construction activities, except when shutdown is
permitted to allow for alterations or final removal of the system per the Engineer. Site
preparation, widening, drainage, guardrail installation, or other work can easily impact existing
conduit runs or luminaire locations. Also, changed conditions such as merging, weaving, or
unusual alignment due to traffic control often require additional temporary illumination.

Note: The same lighting requirements apply whether a condition is temporary or permanent.

Illumination is not required for minor operational enhancement projects, unless that is the
specific reasoning for the project.

1040.04 Required Illumination

The following items are to be considered for each project:
 Replace standard duty junction boxes that are located in paved areas with heavy-duty
junction boxes, and bring electrical components to current standards. Relocate/remove
junction boxes that are located in the travel way when practical.
 Review the age of the equipment as listed in SIMMS and consider replacing
components that have reached the end of their design life. Replace poles, foundations,
heads, and other equipment, that have reached their design life.
 Locate components so that they can be safely accessed from the right of way.
 Ensure existing slip base features are in accordance with current design standards.
 Consider additional illumination in accordance with 1040.05, if warranted, or design
additional illumination if it is called for in the Project Definition.
 When it is necessary to relocate existing light standard foundations, evaluate the entire
conduit run serving those light standards and replace deficient components to current
(NEC) standards.

Exhibits 1040-1a through 1040-21 show examples of illumination for roadway, transit flyer
stops, parking lots, truck weigh stations, tunnels, bridges, work zones, and detour applications.

A minimum of two light standards of standard pole height are required at all design areas, with
the exception of some ramp terminals, entrance/exit points at minor parking lots, and basic
transit stop lighting.

1040.04(1) Freeway Off-Ramps and On-Ramps

Provide the necessary illumination for the design area of all freeway off-ramp gore areas and
on-ramp acceleration tapers (see 1040.06(2) and Exhibits 1040-1a, 1b, and 1c).

1040.04(2) Freeway Ramp Terminals

Provide the necessary illumination for the design area (see Exhibit 1040-2). Ramp terminals may
use a single light standard where all of the following are true:

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 The ramp terminal is stop controlled (no traffic signal).

 The on and off-ramps are a single lane, regardless of width.
 The cross street is two lanes with no channelization.
 There are no sidewalks or marked crosswalks.

Verify with the HQ Traffic Office that the location is acceptable for a single light standard.

1040.04(3) Freeway On-Ramps With Ramp Meter Signals

Provide the necessary number of light standards to illuminate freeway on-ramps with ramp
meters, from 150’ before the ramp meter stop bar to 50’ past the ramp meter stop bar. When
there is an HOV bypass lane or a two-lane merge beyond the ramp meter, then also provide
illumination from the point where the merging lane width is 10’ to 200’ downstream of that
point (see Exhibit 1040-3). Illumination for the ramp merge with mainline is to be done per
Exhibit 1040-1b.

1040.04(4) HOT (High-Occupancy Toll) Lane Enter/Exit Zones and Access

Weave Lanes
Provide the necessary number of luminaires to illuminate the design area of the enter/exit
zones and access weave lanes of the HOT lane (see Exhibits 1040-4a and 4b).

1040.04(5) Lane Reduction

Provide the necessary number of light standards to illuminate the design area of all highway
lane reduction areas within the urban boundary (see Exhibit 1040-5). This requirement does not
apply to:
 The end of slow-moving vehicle turnouts.
 The end of the area where driving on shoulders is allowed.

1040.04(6) Intersections With Left-Turn Lane Channelization

Illumination of the intersection area is required for intersections with painted or other low-
profile pavement markings such as raised pavement markings. When the channelization is
delineated with curbs, raised medians, or islands, illuminate the raised channelization on the
State Route from 25’ before the raised channelization begins (see Exhibits 1040-6a, 6b, and 6c).

1040.04(7) Intersections With Traffic Signals

Illuminate intersections with traffic signals on state highways (see Exhibit 1040-7). In cities with
a population under 27,500, the state may assume responsibility for illumination installed on
signal standards.

1040.04(8) Roundabouts
Provide the necessary number of light standards to illuminate the design areas of roundabouts
(see Chapter 1320 and Exhibit 1040-9).

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1040.04(9) Railroad Crossings with Gates or Signals

Railroad crossings with automated gates or signals on state highways are illuminated if there is
nighttime train traffic. Within the corporate limits of a city, and outside limited access control,
illumination is the responsibility of the city. Install luminaires beyond the railroad crossing, on
the side of the roadway opposite the approaching traffic, to backlight the train (see Exhibit
1040-10).

1040.04(10) Midblock Pedestrian Crossings

Illuminate the entire midblock pedestrian crossing, including the crosswalks, the refuge area in
the roadway, and the sidewalks or shoulders adjacent to the crosswalk. When a raised median
pedestrian refuge design is used, illuminate the raised channelization (see Exhibit 1040-11).

1040.04(11) Transit Flyer Stops

Illuminate the pedestrian-loading areas of transit flyer stops, as described in Chapter 1420 (see
Exhibit 1040-12). For all other types of transit stops, see 1040.05(8).

1040.04(12) Major Parking Lots

All parking lots with usage exceeding 50 vehicles during the nighttime peak hour are considered
major parking lots. Provide an illumination design that will produce the light levels shown in
Exhibit 1040-22. (See Exhibit 1040-13 for the parking design area and bus loading zone design
area.) During periods of low usage at night, security lighting is required only in the parking area
and bus loading zone. Provide an electrical circuitry design that allows the illumination system to
be reduced to approximately 25% of the required light level.

1040.04(13) Minor Parking Lots

Minor parking lots have a nighttime peak hour usage of 50 or fewer vehicles. Provide security-
level lighting for those lots owned and maintained by the state. Security lighting for a minor
parking lot consists of lighting the entrance and exit to the lot (see Exhibit 1040-14).

1040.04(14) Truck Weigh Sites

Provide illumination of the roadway diverge and merge sections, scale platforms, parking areas,
and inspection areas of weigh sites (see Exhibit 1040-15).

1040.04(15) Safety Rest Areas

Provide illumination within rest areas at the roadway diverge and merge sections, the walkways
between parking areas and rest room buildings, and the parking areas the same as for a major
parking lot (see Exhibit 1040-16).

1040.04(16) Chain-Up/Chain-Off Parking Areas

Provide the necessary number of luminaires to illuminate the design area of the chain-up/chain-
off parking areas (see Exhibit 1040-17) on State Routes 2, 12, and 90 where a power distribution
point is within a half mile and power is readily accessible. Illumination is to be installed in the
median and on the right shoulder to provide lighting on both sides of the stopped vehicles.

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Luminaires should only be energized during periods when traction tires are required and
vehicles over 10,000 pounds are required to use chains.

1040.04(17) Tunnels, Lids, and Underpasses

For the purposes of this chapter, a tunnel is a structure over a roadway, which restricts the
normal daytime illumination of a roadway section such that the driver’s visibility is substantially
diminished. Tunnels cover roadways and produce a shadow that limits the ability of the driver to
see objects or obstructions within the tunnel. In most locations, no supplemental daytime
lighting is required for underpasses or structures less than 80 feet in length. Provide both
nighttime and daytime lighting for long tunnels. (See ANSI/IES publication RP-22-11 for tunnel
lighting design criteria.) Provide vandal-resistant daytime and nighttime security lighting in
pedestrian tunnels. Short tunnels and underpasses where the exit portal is not visible from the
entrance portal due to curvature of the roadway are to be considered long tunnels.

1040.04(18) Bridge Inspection Lighting

Provide the necessary number of light fixtures and electrical outlets to illuminate the interior
inspection areas of floating bridges, steel box girder bridges and concrete box girder bridges
where access is provided (see Exhibit 1040-18). Separate circuits are to be used for lighting and
electrical outlets. Each electrical outlet is to be powered by 2 Duplex receptacles on two
separate circuits. All electrical outlets are to be labeled with circuit identifications. Coordinate
bridge illumination requirements with the HQ Bridge and Structures Office.

1040.04(19) Same Direction Traffic Split Around an Obstruction

Provide the necessary number of light standards to illuminate the design area where traffic is
split around an obstruction. This requirement applies to permanent and temporary same-
direction split channelization. For temporary work zones, illuminate the obstruction for the
duration of the traffic split (see Exhibit 1040-19).

1040.04(20) Diverging Diamond Interchange

Provide the necessary number of light standards to illuminate the design area shown in Exhibit
1040-21. The design area starts 25’ before the raised channelization as you approach the
interchange and continues through the interchange until 25’ past the raised channelization as
you exit the interchange.

1040.05 Additional Illumination

At certain locations, additional illumination is desirable to provide better definition of nighttime
driving conditions or to provide consistency with local agency goals and enhancement projects.
For Improvement projects on state highways, additional illumination could be reviewed as a
crash countermeasure under certain circumstances, which are listed in this section.

1040.05(1) Conditions for Additional Illumination

Following are some conditions used in making the decision to provide additional illumination:

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1040.05(1)(a) Crash Analysis

The following conditions have to be met when making the decision to provide additional
illumination:
 During the last full five calendar years, the site has experienced nighttime crashes that
are correctable with illumination, AND
 The benefit-cost analysis for the proposed illumination exceeds 1, AND
 Alternative lower-cost countermeasures have been evaluated and did not address the
particular nighttime crash history.

Nighttime crashes are defined as crashes occurring between half an hour after sunset and half
an hour before sunrise. Correctable nighttime crashes are crashes that (a) meet the nighttime
definition in this chapter, (b) have contributing factors related to a lack of lighting, and (c) where
lighting, if installed, would directly address the contributing factor(s) to the crashes.

Collision reporting forms and the crash data are not adequate means to distinguish between day
and nighttime conditions: the crash location, the reported crash times, and seasonal variations
should be used to determine which crashes qualify as nighttime crashes. Also:
 For sites where the number of nighttime crashes equals or exceeds the number of
daytime crashes, the above-mentioned crash and benefit-cost analysis should be
performed.
 For sites where these nighttime crashes involve pedestrians, refer to 1040.05(11).

1040.05(1)(b) Locations With Nighttime Pedestrian Crashes

The mitigation of nighttime pedestrian crashes requires different lighting strategies than
vehicular crash locations. Provide light levels to emphasize crosswalks and adjacent sidewalks by
using positive lighting of the pedestrians.

Multilane highways with two-way left-turn lanes, in areas transitioning from rural land use to
urban land use, or areas experiencing commercial growth or commercial redevelopment, are
typically high-speed facilities with numerous road approaches and driveways. These approaches
allow numerous vehicle entry and exit points and provide few crossing opportunities for
pedestrians; consider additional illumination.

1040.05(2) Highways
Proposals to provide full (continuous) illumination require the approval of the Region and State
Traffic Engineers. Regions may choose to develop (regional or corridor-specific) system plans for
providing full (continuous) illumination. The State Traffic Engineer’s approval of a system plan
will eliminate the need for a project-specific approval from the State Traffic Engineer.
Continuous illumination can be provided inside city limits at the city’s request provided the city
takes on the maintenance and operational costs and responsibilities of maintaining and
operating the system.

The decision whether to provide full (continuous) illumination is to be made during the scoping
stage and communicated to the designers as soon as possible.

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Continuous illumination should be considered when the crash analysis requirements in

1040.05(1) are met and a benefit/cost analysis between the required and full (continuous)
illumination exceeds 1.

On the main line of highways without full limited access control, consider full (continuous)
illumination if the segment of highway is in a commercial area and the crash analysis
requirements in 1040.05(1) are met, has raised channelization, has medium or high pedestrian
activity during night time hours, and an engineering study indicates that nighttime driving
conditions will be improved.

1040.05(3) Ramps
Consider additional illumination at ramps where the alignment or grade is complex.

1040.05(4) Crossroads
Consider additional illumination if the crossroad is in a short tunnel, an underpass, or a lid.

1040.05(5) Intersections Without Turn-Lane Channelization

Refer to Exhibit 1040-8.

1040.05(6) Short Tunnels, Underpasses, or Lids

Consider illumination of the sidewalk, walkway, or shared-use path if it is included as part of the
short tunnels, underpasses, or lids.

1040.05(7) Work Zones and Detours

Consider temporary illumination of the highway through work zones and detours when changes
to the highway alignment or grade remain in place during nighttime hours. Exhibit 1040-20
illustrates considerations for temporary illumination, such as reduced roadway widths, work
zone lane shifts, and median cross overs.

For further information on illumination in work zones, see Chapter 1010.

1040.05(8) Transit Stops

The responsibility for lighting at transit stops is shared with the transit agency. Consider
illuminating transit stops with shelters as they usually indicate greater passenger usage.
Negotiation with the transit agencies is required for the funding and maintenance of this
illumination. Negotiating a memorandum of understanding (MOU) with each transit agency is
preferred over spot negotiations. If the transit agency is unable or unwilling to participate in the
funding and maintenance of the illumination, consider a single light standard positioned to
illuminate both the transit pullout area and the loading area.

1040.05(9) Bridges
Justification for illuminating the roadway/sidewalk portion of bridges is the same as that for
highways on either end of the bridge with or without full limited access control, as applicable.
Justification for illuminating the architectural features of a bridge structure requires the

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approval of the State Traffic Engineer. For justification for illuminating pedestrian walkways or
bicycle trails under a bridge, see 1040.05(11).

1040.05(10) Railroad Crossing Without Gates or Signals

Consider the illumination of railroad crossings without gates or signals when:
 The crash history indicates that motorists experience difficulty in seeing trains or
control devices.
 There are a substantial number of rail operations conducted during nighttime hours.
 The crossing is blocked for long periods due to low train speeds.
 The crossing is blocked for long periods during the nighttime.

For further information, see the MUTCD.

1040.05(11) Sidewalks, Walkways, and Shared-Use Paths

Consider illumination of a pedestrian walkway if the walkway is a connection between two
highway facilities. This could be between parking areas and rest room buildings at rest areas;
between drop-off/pick-up points and bus loading areas at flyer stops; or between parking areas
and bus loading areas or ferry loading zones. Consider illuminating existing sidewalks, walkways,
and shared-use paths if security problems have been reported or are anticipated. Under these
conditions, these facilities are illuminated to the level shown in Exhibit 1040-22.

1040.06 Design Criteria

1040.06(1) Light Levels

Light levels vary with the functional classification of the highway, the development of the
adjacent area, and the level of nighttime activity. Light level requirements for highways and
other facilities are shown in Exhibit 1040-22. These levels are the minimum average light levels
required for a design area at the end of rated lamp life for applications requiring a spacing
calculation. Light level requirements are not applicable for single light standards or security
lighting installations where:
 The light level is reduced to approximately 25% of the required light level in parking
lots and parking lot loading areas during periods of low usage at night.
 Walkway or path illumination is installed only at areas where shadows and horizontal
and vertical geometry obstruct a pedestrian’s view.
Light level requirements still apply when the complete walkway or path is to be illuminated
for public safety.

The access areas used for interior inspection of floating bridges or steel box/concrete box girder
bridges are exempt from lighting level and lighting ratio design requirements.

For functional classifications of highways, see:

 www.wsdot.wa.gov/mapsdata/travel/hpms/functionalclass.htm

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1040.06(1)(a) Activity Areas

The types of activity areas (shown below) are related to the number of pedestrian crossings
through the design area. These crossings need not occur within a single crosswalk and can be at
several locations along the roadway in an area with pedestrian generators. Land use and activity
classifications are as follows:
1040.06(1)(a)(1) High Activity

Areas with over 100 pedestrian crossings during nighttime peak hour pedestrian usage.
Examples include downtown retail areas; near outdoor stage theaters, concert halls, stadiums,
and transit terminals; and parking areas adjacent to these facilities.
1040.06(1)(a)(2) Medium Activity

Areas with pedestrian crossings that number between 11 and 100 during nighttime peak hour
pedestrian usage. Examples include downtown office areas; blocks with libraries, movie
theaters, apartments, neighborhood shopping, industrial buildings, and older city areas; and
streets with transit lines.
1040.06(1)(a)(3) Low Activity

Areas with pedestrian crossings that number less than 11 during the nighttime peak hour
pedestrian usage. Examples include suburban single-family areas, low-density residential
developments, and rural or semirural areas.

1040.06(2) Design Areas

The design area is that portion of the roadway, parking lot, or other facility subject to the
minimum light level, minimum average light level, uniformity ratio, and maximum veiling
luminance ratio design requirements. This encompasses the area between the edges of the
traveled way along the roadway; the outer edges of the stopping points at intersections; and,
when present, a bike lane adjacent to the traveled way. When the roadway has adjacent
sidewalks and is located in a medium or high pedestrian activity area, the design area includes
these features; however, sidewalks adjacent to the traveled way are exempt from maximum
veiling luminance ratio requirements.
1040.06(2)(a) Design Area Requirements

Design area requirements for various applications are shown in Exhibits 1040-1a through 1040-
21 and are described in the following:
1040.06(2)(a)(1) Single-Lane Off-Ramp

Two main line through lanes and the ramp lane, including gore area, from the gore point
(beginning of wide line) to a point 200 feet (minimum) downstream of the gore point. A 100 foot
longitudinal tolerance either way from the gore point is allowed.
1040.06(2)(a)(2) Two-Lane Off-Ramp

Two main line through lanes and both ramp lanes, including gore area, from a point 200 feet
upstream of the gore point (beginning of wide line) to a point 200 feet downstream of the gore
point. A 100-foot longitudinal tolerance either way from the gore point is allowed.

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1040.06(2)(a)(3) Single-Lane On-Ramp

Two main line through lanes and the ramp lane, from a point where the ramp lane is 10 feet
wide to a point 200 feet downstream. A 100-foot longitudinal tolerance either way is allowed;
this includes auxiliary lane on-connections and lane reductions.
1040.06(2)(a)(4) Two-Lane On-Ramp

Two main line through lanes and the ramp lanes from a point where the ramp width is 22 feet
wide to a point 200 feet upstream and 200 feet downstream. A 100-foot longitudinal tolerance
either way is allowed.
1040.06(2)(a)(5) Intersections Channelized With Pavement Markings

When the leg of an intersection is two lanes wide or less, the design area starts at the stop bar
and encompasses the intersection area. When the leg of an intersection is three or more lanes
wide, the design area starts 25’ before the stop bar and encompasses the intersection area.
1040.06(2)(a)(6) Intersections With Raised Channelization

The design area has two components: the intersection area and the approach areas. When the
leg of an intersection is two lanes wide or less, the intersection design area starts at the stop bar
and encompasses the intersection area. When the leg of an intersection is three or more lanes
wide, the intersection design area starts 25 feet before the stop bar and encompasses the
intersection area on both the main road and the minor road, including marked or unmarked
crosswalks. The approach areas are the areas on the main roadway between the intersection
design area and where the left-turn taper begins.
1040.06(2)(a)(7) Unchannelized Intersection

The area between the stopping points on both the main road and the minor road, including
marked or unmarked crosswalks.
1040.06(2)(a)(8) Railroad Crossing

The roadway width from a point 50 feet on either side of the track (the approach side only for
one-way roadways).
1040.06(2)(a)(9) Transit Loading Area

The lane width and length designated for loading.

1040.06(2)(a)(10) Major Parking Lot

The entire area designated for parking, including internal access lanes.
1040.06(2)(a)(11) Scale Platform at Weigh Site

The approach width from the beginning of the scale platform to the end of the platform.
1040.06(2)(a)(12) Inspection Area at Weigh Site

The area dedicated to inspection as agreed upon with the Washington State Patrol.

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1040.06(2)(a)(13) Bridge Inspection Lighting System

Fixtures are to be ceiling mounted. For steel box girders bridges, the spacing shall not be greater
than the smaller of 4 times the web depth or 25 ft. For concrete box girder bridges, the spacing
shall not be greater than the smaller of 8 times the web depth or 50 ft. Illumination is to consists
of a 100 watt incandescent (or fluorescent equivalent) fixture. The bulb should have a minimum
of 1600 lumens. Each fixture is to be designed with a 20 amp rated ground fault circuit interrupt
(GFCI) receptacle. A light switch is needed at each entrance to any common inspection area. For
inspection areas with two or more entrances, three-way or four-way switches are required.

1040.06(3) Daytime Light Levels for Tunnels, Lids, and Underpasses

It is important to provide sufficient illumination inside a tunnel. When driving into and through a
tunnel during the day, a driver’s eyes have to adjust from a high light level (daylight) to a lower
lighting level inside the tunnel. Motorists require sufficient time for their eyes to adapt to the
lower light level of the tunnel itself. When sufficient lighting is not provided in the threshold,
transition, or interior zones of a tunnel, a motorist’s eyes may not have enough time to adapt
and may experience a “black hole” or “blackout” effect. This “black hole” effect may cause a
motorist to slow down, reducing the efficiency of the roadway. When leaving the tunnel, the
driver’s eyes have to adjust from a low lighting level back to daytime conditions. The full design
considerations for tunnel lighting are covered in 1040.08(2) in the Design Guidance section.
 All designs for illuminating tunnels are to be reviewed and approved by the State
Traffic Engineer.
 Long tunnels are divided into zones for the determination of daytime light levels. The
zones are Threshold Zone, Transition Zone(s), and Interior Zone. Each zone length is
calculated using the method described in ANSI/IES RP-22-11.
 The designer of a long tunnel shall perform a Lseq (Equivalent Veiling Luminance)
calculation. Lseq values obtained from this calculation shall be used to reduce (or
increase) the Suggested Daytime Maintained Average Pavement Luminance Levels
where indicated.
 Tunnel wall illumination is required.
 The approach and exit roadways shall have a nighttime luminance level of no less than
one third of the tunnel interior level for one safe stopping sight distance (SSSD).
 Provide illumination of fire protection equipment, alarm pull boxes, phones, and
emergency exits in long tunnels. (See NFPA 502 for additional information.)
 Short tunnels and underpasses in rural areas or with low pedestrian usage normally do
not have daytime illumination. Short tunnels and underpasses in urban areas with high
pedestrian usage may require daytime and nighttime illumination. Consultation with
the affected local agency is recommended. Short tunnels and underpasses are treated
the same as an entrance zone on a long tunnel to establish daytime light levels.
 Nighttime light level requirements for short tunnels on continuously illuminated
roadways are the same as the light level required on the roadway outside the tunnel.

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1040.06(4) Light Standards

1040.06(4)(a) Light Standards on State Highway Facilities

Light standards are the most common supports used to provide illumination for highway
facilities. The 40-foot light standard with a slip bases and Type 1 mast arm is predominantly
used on state highways. In areas with continuous illumination, 50-foot light standards may be
used. Use Type 1 mast arms on all new systems and when modifying existing systems. Cities and
counties may elect to use different mounting heights to address factors unique to their
environments. On state highways, alternative colored light standards may be considered if
requested by the city or county, provided they agree to pay any additional costs associated with
this change.

The typical location for a light standard is on the right shoulder. When considering designs for
light standards mounted on concrete barrier in the median, consider the total life cycle cost of
the system, including the user costs resulting from lane closures required for relamping and
repair operations, and higher maintenance costs since the work will most likely be done during
night time hours due to decreased traffic volumes. Region Signal Maintenance approval is
required for all median mounted luminaires except chain on/off areas. Light standards located in
the vicinity of overhead power lines require a minimum 10 foot circumferential clearance from
the power line (including the neutral conductor) to any portion of the light standard or
luminaire. Depending on the line voltage, a distance greater than 10 feet may be required (WAC
296-24-960). Consult the HQ Bridge and Structures Office when mounting light standards on
structures such as retaining walls and bridge railings.

It is preferable to locate a light standard as far from the traveled way as possible to reduce the
potential for impacts from errant vehicles. The typical luminaire position is mounted directly
over the edge line plus or minus 4 feet. However, some flexibility is acceptable with the
luminaire position to allow for placement of the light standard provided light levels, uniformity,
and maintenance considerations are addressed, and with the Region Traffic Engineer’s approval.
On Type III signal standards, luminaires may be placed more than 4 feet from the edge line.

Standard mast arm lengths are available in 2-foot increments between 6 and 16 feet. The
preferred design for a single-arm light standard is a 16-foot mast arm installed on a 40-foot
standard. The maximum allowable mast arm length for a single-arm light standard is 16 feet.
The preferred design for a double mast arm light standard has mast arms between 6 feet and 12
feet in length, installed on a 40-foot standard. The maximum allowable mast arm length for a
double luminaire light standard is 12 feet.

Light standards should always use slip bases, unless a fixed base is justified as described in
Chapter 1610.
 In curb and sidewalk sections, locate the light standard behind the sidewalk. In
locations where the light standard cannot be placed behind the sidewalk and still have
the luminaire mounted within 4’ of the edge line, the luminaire should be located in
the sidewalk. When installed in the sidewalk, ensure that the minimum sidewalk width
is available to at least one side of the light standard for the pedestrian access route
(see Chapter 1510).

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1040.06(4)(b) Light Standard Heights

Standard pole heights (20-foot, 30-foot, or 40-foot) are readily available from local distributors
and manufacturers. Light standards can also be supplied with other lengths. However, WSDOT
Maintenance offices cannot stock poles with nonstandard lengths for use as replacements in the
event of a knockdown. Nonstandard lengths in 5-foot increments (25-foot, 35-foot, or 45-foot)
will require a longer delivery time. Other nonstandard lengths (for example, 27-foot, 33-foot, or
37-foot) will not only require a longer delivery time, they will also be more expensive.

In almost all cases, use a standard pole heights of 40 feet for roadway illumination. Structure-
mounted light standards may need to be shorter than the standard 40-foot grade-mounted
pole. It is acceptable to use 20-foot or 30-foot light standards on bridges, retaining walls, or
other structures to compensate for top-of-structure elevation above the roadway surface.
Luminaires with a mounting height over 40 feet should only be used in continuously illuminated
areas that are not in residential areas. Use of these standard pole heights will result in variable
mounting heights for the luminaires. Luminaire mounting height is defined as the actual
distance from the roadway surface directly under the luminaire to the luminaire itself. Use the
actual mounting height at each location when calculating light standard spacing. Luminaires
with a mounting height over 50 feet require lowering devices.

High mast light supports may be considered for complex interchanges where continuous lighting
is justified. High mast lighting may be considered for temporary illumination areas during
construction. Initial construction costs, long-term maintenance, clear zone mitigation, spillover
light onto adjacent properties, and negative visual impacts are important factors when
considering high mast illumination.

Shorter light standards of 30 feet or less may be used for minor parking lots, trails, pedestrian
walkways, and locations with restricted vertical clearance.
1040.06(4)(c) Standard Luminaire

The standard luminaire in use now for roadway lighting is a cobra head style type III LED fixture.
The list of LED fixtures approved for use on WSDOT projects can be found at:
 http://www.wsdot.wa.gov/Design/Traffic/ledluminaires.htm

For continuously illuminated area a type V distribution pattern can be used for the interior areas
with type III distribution on the perimeters.

1040.06(4)(d) Electrical Design

For an example of circuit layout, conductor sizing, conduit sizing, overcurrent protection device
sizing, and other electrical design calculations, see the Power Supply Design material located at:
 http://www.wsdot.wa.gov/design/traffic/electrical/training.htm

An example of illumination design grid layouts and calculations is located in the Illumination
Design for Transportation Applications material located in the link above.

The illumination circuitry is to be laid out so that if four or more luminaires are installed, it
should have a minimum of two circuits. The intent is to make sure that if a circuit fails, there will
still be partial lighting from the other circuits.

The maximum allowable junction box spacing is as follows:

1. 360 feet allowed between in grade junction boxes with a straight pull.

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2. 180 feet when conduit run is along a curve or when the conduit makes a 30 degree or
greater change in direction.
3. 180 feet between NEMA junction boxes in traffic barrier, retaining wall, or structure.
4. A junction box is required within 5 feet minimum (preferred) & 10 feet maximum of the
luminaire base, regardless of the luminaire spacing.
5. 360 feet between NEMA junction boxes when fiber optic cable is run through conduit in
traffic barrier, retaining wall, or structure.
6. Pull Box interconnect to Traffic Signal – spacing is 500 feet maximum. Disclaimer: This would
only apply to a single fiber optic cable.
7. 1,000 feet between cable vaults or pull boxes – main line fiber optic cable.

1040.06(5) Adaptive Lighting

Adaptive Lighting Systems may be used at select locations where changing traffic conditions
allow for lowering of light levels or the changing of a required design area. Some examples
would be: the Pedestrian/Area Classification changes requiring different levels; traffic volumes
drop sharply; or chain up/chain off areas. Region and State Traffic Engineers’ approval is
required for adaptive lighting systems.

1040.07 Documentation
Justify and document any additional illumination in the Design Documentation Package (DDP).

The approval from maintenance to install median mounted luminaires can be an email or memo
from the area maintenance superintendent and is kept in the design file.

Any areas in this section that says to “consider” a design element should have the logic of the
consideration and decision documented in the design file for future reference.

Refer to Chapter 300 for design documentation requirements.

1040.08 References

1040.08(1) Federal/State Laws and Codes

National Electrical Code (NEC), NFPA, Quincy, MA

Revised Code of Washington (RCW) 47.24.020, Jurisdiction, control

Washington Administrative Code (WAC) 296-24-960, Working on or near exposed energized

parts

WAC 468-18-040, Design standards for rearranged county roads, frontage roads, access roads,
intersections, ramps and crossings

WAC 468-18-050, Policy on the construction, improvement and maintenance of intersections of

state highways and city streets

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1040.08(2) Design Guidance

American National Standard Practice for Roadway Lighting, IES RP-8-00, New York, NY 2000

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

NFPA 502: Standard for Road Tunnels, Bridges, and Other Limited Access Highways, NFPA,
Quincy, MA 2011

Recommended Practice for Tunnel Lighting, IESNA RP-22-05, New York, NY 2011

Roadway Lighting Design Guide, AASHTO, October 2005

Roadway Lighting Handbook, Addendum to Chapter Six: Designing the Lighting System Using
Pavement Luminance, Federal Highway Administration, Addendum to Implementation Package
78-15, Washington, DC 1983

Roadway Lighting Handbook, Federal Highway Administration, Implementation Package 78-15,

Washington, DC 1978 (Reprinted April 1984)

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

1040.08(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, Current Edition

An Informational Guide for Roadway Lighting, AASHTO, Washington, DC 1984

City Streets as Part of State Highways Guidelines Reached by the Washington State Department
of Transportation and the Association of Washington Cities on Interpretation of Selected Topics
of RCW 47.24 and Figures of WAC 468-18-050 for the Construction, Operations and
Maintenance Responsibilities of WSDOT and Cities for such Streets, 4-30-1997 amended 4-2-
2013

Light Trespass: Research Results and Recommendations, IES TM-11-00, New York, NY 2000

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Exhibit 1040-1a Freeway Lighting Applications

Required Illumination for a Typical Diamond Interchange

Shown for single-lane ramp connection and a two-lane crossroad without channelization.

Single-Lane Off-Connection
The design area may be shifted up to 100 ft from the beginning of the wide line; a minimum
of two light standards of standard pole height required for design area.

Two-Lane Off-Connection: One Exit Only Lane; One Optional Lane

The design area may be shifted up to 100 ft from the beginning of the wide line; a minimum of
three light standards of standard pole height required for design area.

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Illumination Chapter 1040

Exhibit 1040-1b Freeway Lighting Applications

Single-Lane On-Connection
The design area may be shifted up to 100 ft from the 10-ft-wide ramp point; a minimum of
two light standards of standard pole height required for design area.

Auxiliary Lane at On-Connection

The design area may be shifted up to 100 ft from the end of wide line; a minimum of two light standards
of standard pole height required for design area.

Two-Lane On-Connection: One Auxiliary Lane; One Merge Lane

The design area may be shifted up to 100 ft from the 22-ft-wide ramp point; a minimum of three light
standards of standard pole height required for design area.

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Chapter 1040 Illumination

Exhibit 1040-1c Freeway Lighting Applications

Single Exit-Only Lane

The design area may be shifted up to 100 ft from the end of lane and the beginning of wide line;
a minimum of two light standards of standard pole height required for design area.

Two Exit-Only Lanes

The design area may be shifted up to 100 ft from the end of lane and the beginning of wide line; a
minimum of three light standards of standard pole height required for design area.

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Illumination Chapter 1040

Exhibit 1040-2 Freeway Ramp Terminals

Off Ramp with Single-Lane Crossroad

Off-Ramp with Multilane Crossroad

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Chapter 1040 Illumination

Exhibit 1040-3 Ramp with Meter

Single-Lane On-Ramp

Multilane On-Ramp with HOV Bypass Lane

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Illumination Chapter 1040

Exhibit 1040-4a HOT (High-Occupancy Toll) Lane Enter/Exit Zone

A minimum of two light standards of standard pole height required for each design area.

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Chapter 1040 Illumination

Exhibit 1040-4b HOT (High-Occupancy Toll) Lane ACCESS WEAVE LANE

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Illumination Chapter 1040

Exhibit 1040-5 Lane Reduction

A minimum of two light standards of standard pole height required for design area;

design area may be shifted 100 ft.

Exhibit 1040-6a Intersection with Left-Turn Channelization: Divided Highway

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Chapter 1040 Illumination

Exhibit 1040-6b Intersections with Left-Turn Channelization

Intersection with Low-Profile Left-Turn Channelization Pavement Markings

Exhibit 1040-6c Intersections with Raised Left-Turn Channelization

Intersection with Raised Left-Turn Channelization

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Illumination Chapter 1040

Exhibit 1040-7 Intersections with Traffic Signals

Four-Way Intersection with Single-Lane Approaches

Four-Way Intersection with Multilane Major Approaches

A minimum of two light standards required for design area.

Minor Tee Intersection Major Tee Intersection

A minimum of two light standards is
required for design area.

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Chapter 1040 Illumination

Exhibit 1040-8 Intersection without Channelization

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Illumination Chapter 1040

Exhibit 1040-9 Roundabout Notes

1. Exclude Truck Apron from lighting
calculations.
2. Exclude the portion inside the 2ft
offset areas of the raised
channelization islands from
calculation.
3. All channelization 2ft wide or less is
included in the Approach Design Area
calculation.
4. When a leg of the roundabout is a
one-way roadway, the Approach
Design Area starts at the beginning of
the raised channelization, or 50ft
from the outside edge of the
circulating roadway, or 50ft beyond a
sidewalk, whichever is further.
5. A sidewalk is included in the
Intersection Design Area calculation
when a planting strip is less than 15ft
wide.
6. Install luminaire to provide positive
illumination of raised channelization.
The preferred luminaire location
would be from 20’ to one mounting
height’s distance in front of the
raised channelization.
7. Do not install luminaire in the area
from 20’ in front of the crosswalk to
20’ past the crosswalk.
8. Install luminaire to provide positive
illumination of the crosswalk for
approaching vehicles. The preferred
luminaire location would be one
mounting height’s distance in front of
the crosswalk.
9. If approach intersection area requires
more than one luminaire, the last
luminaire on that approach chain can
be replaced with a ground-mounted,
internally illuminated bollard with
sign in place of 2nd luminaire.

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Chapter 1040 Illumination

Exhibit 1040-10 Railroad Crossing with Gates or Signals

Exhibit 1040-11 Midblock Pedestrian Crossing

A minimum of two light standards of standard height is required for the design area.

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Illumination Chapter 1040

Exhibit 1040-12 Transit Flyer Stop

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Exhibit 1040-13 Major Parking Lot

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Illumination Chapter 1040

Exhibit 1040-14 Minor Parking Lot

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Exhibit 1040-15 Truck Weigh Site

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Exhibit 1040-16 Safety Rest Area

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Exhibit 1040-17 Chain-Up/Chain-Off Parking Area

Taper varies - Taper varies -

See Ch. 1270 See Ch. 1270

Begin chain-up/ End chain-up/chain-off area

chain-off area
Full-width parking area

Legend

Design Area with 0.9 fc

Design Area with 1.6 fc

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Illumination Chapter 1040

Exhibit 1040-18 Bridge Inspection Lighting System

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Exhibit 1040-19 Traffic Split Around an Obstruction

Note:
For temporary work zone plan applications, a site-specific traffic control plan is required. Refer to Chapters 1610
and 1620 for traffic barrier and attenuator information, Chapter 1010 for work zone information, and Chapter
1020 for signing information.

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Exhibit 1040-20 Construction Work Zone and Detour

Detour Traffic

Lane Closure with Barrier and Signals without Flaggers or Spotters

One-direction closure shown/other direction closure typical.

Note:
For temporary work zone plan applications, a site-specific traffic control plan is required. Refer to Chapters 1610
and 1620 for traffic barrier and attenuator information, Chapter 1010 for work zone information, and Chapter
1020 for signing information. Refer to the MUTCD Typical Application 12 for additional details.

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Exhibit 1040-21 Diverging Diamond Interchange

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Illumination Chapter 1040

Exhibit 1040-22 Light Levels and Uniformity Ratios

Light Level and Uniformity Ratio Chart

Minimum Average Maintained
Horizontal Light Level Maximum
Maximum
Veiling
Highway Design Class Pedestrian/Area Classification Uniformity
Luminance
Ratio [5]
High Medium Low Ratio [6]
(footcandles) (footcandles) (footcandles)

Highways With Full Access Control [1][8]

Main Line 0.6 0.6 0.6 4:1 0.3:1

Ramps 0.6 0.6 0.6 4:1 0.3:1
Crossroads 0.6 0.6 0.6 4:1 0.3:1
Ramp Intersections 0.9 [2] 0.9 [2] 0.9 [2] 4:1 [2] 0.3:1

Highways Without Full Access Control [3][8]

Main Line 1.2 0.9 0.6 4:1 0.3:1

Intersections 1.2 0.9 0.9 4:1 0.3:1

Other Illuminated Features

Construction Lanes and Detours 1.0 1.0 1.0 4:1 0.3:1

Major Parking Lots/Rest Areas 0.8 0.8 0.8 4:1 0.3:1
Vehicle Inspection Areas 2.0 2.0 2.0 4:1 0.3:1

Sidewalks, Walkways & Shared Use Paths 0.8 0.8 0.8 4:1 0.3:1
Weigh Scales 0.8 0.8 0.8 4:1 0.3:1
Transit Stops [4] 2.0 2.0 2.0 NA [7] 0.3:1
Midblock Ped X-ing 2.0 2.0 2.0 4:1 0.3:1

Notes:
[1] The minimum light level is 0.2 footcandle (fc) for any application with a minimum average maintained
horizontal light level of 0.6 fc. The minimum light levels for all other applications are controlled by the
uniformity ratio.
[2] The minimum average maintained light level may be reduced to 0.6 fc and the uniformity ratio may be ignored
when only one light standard is used. Also applies to minor parking lot entrances and exits, and basic transit
stop lighting.
[3] Light levels shown also apply to modified and partial limited access control.
[4] For single light standard installations, provide the light level at the location where the bus stops for riders
(see Exhibit 1040-12).
[5] Minimum Average Maintained Light Level/Minimum Light Level = Maximum Uniformity Ratio.
[6] Maximum Veiling Luminance/Average Luminance = Maximum Veiling Luminance Ratio.
[7] The Maximum Uniformity Ratio is 4:1 when more than one light standard is justified.
[8] Roundabout illumination shall meet intersection lighting requirements for the associated roadway classification.

Page 1040-40 WSDOT Design Manual M 22-01.15

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Chapter 1040 Illumination

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Chapter 1050 Intelligent Transportation Systems
1050.01 General
1050.02 References
1050.03 Systems Engineering
1050.04 FHWA Washington Division ITS Project Contracting Guidance
1050.05 Documentation

1050.01 General
Intelligent Transportation Systems (ITS) have the potential to reduce crashes and increase
mobility of transportation facilities. They also enhance productivity through the use of advanced
communications technologies and their integration into vehicles and the transportation
infrastructure. These systems involve a broad range of wireless and wire line communications-
based information, electronics, or information processing technologies. Some of these
technologies include cameras, variable message signs, ramp meters, road weather information
systems, highway advisory radios, traffic management centers, and adaptive signal control
technology (ASCT). ASCT is a traffic signal system that detects traffic conditions and adjusts
signal timing remotely in response. More information on ASCT can be found at:
 www.fhwa.dot.gov/everydaycounts/technology/adsc

The purpose and direction of ITS for the Washington State Department of Transportation
(WSDOT) can be found in the Statewide Intelligent Transportation Systems Plan, which is
available upon request from the Headquarters (HQ) Traffic Operations Office. The plan identifies
the current and long-term ITS needs to meet the objectives identified in Moving Washington,
WSDOT’s program to fight traffic congestion.

The Statewide ITS Plan is a comprehensive document that discusses:

• The history of ITS deployment in Washington.
• How ITS meets WSDOT’s transportation vision and goals.
• The current state of ITS deployment.
• WSDOT’s near-term ITS plans.
• How projects are prioritized.
• What long-term ITS issues WSDOT needs to begin planning for.

Due to the dynamic nature of ITS, printed guidance is soon outdated. Detailed design guidance
and current practices are located on the following websites. For additional information and
direction, contact the region Traffic Engineer or the HQ Traffic Operations Office:
 www.wsdot.wa.gov/design/traffic/

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1050.02 References
23 Code of Federal Regulations (CFR), Part 940, Intelligent Transportation System
Architecture and Standards
 http://www.ecfr.gov

USDOT, Systems Engineering for Intelligent Transportation Systems, FHWA-HOP-07 069,

January 2007
 http://ops.fhwa.dot.gov/publications/seitsguide/index.htm

USDOT/CalTrans, Systems Engineering Guidebook for Intelligent Transportation Systems,

Version 3, November 2009
 http://www.fhwa.dot.gov/cadiv/segb/

USDOT, Model Systems Engineering Documents for Adaptive Signal Control Technology
(ASCT) Systems, FHWA HOP-11-027, August 2012
 http://www.ops.fhwa.dot.gov/publications/fhwahop11027/index.htm

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as
adopted and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices
for streets and highways” (MUTCD)
 www.wsdot.wa.gov/publications/manuals/mutcd.htm

SAFETEA-LU (Safe Accountable Flexible Efficient Transportation Equity Act: A Legacy for Users)
 http://www.fhwa.dot.gov/safetealu/index.htm

MAP-21 (Moving Ahead for Progress in the 21st Century Act)

 http://www.fhwa.dot.gov/map21/

WSDOT Northwest Region Traffic Design

 http://www.wsdot.wa.gov/northwest/trafficdesign

WSDOT Traffic Design

 http://www.wsdot.wa.gov/design/traffic/

1050.03 Systems Engineering

Systems engineering is a typical part of any ITS project development process. It is required on
any federal-aid project that has an ITS work element, per 23 CFR 940.11. Systems engineering
is an interdisciplinary step-by-step process for complex projects (such as ITS projects) to:
• Assess a system’s needs and its relationship to the regional architecture.
• Plan a project that meets those needs as well as stakeholder needs and expectations.
• Define other specific requirements for the project/system.
• Develop and implement the project/system.
• Define the operations and maintenance requirements for the system.
• Plan for the refinement or replacement of the system.

Using systems engineering on ITS projects has been shown to increase the likelihood of a
project’s success. A successful project is one that meets the project scope and stakeholder/
project sponsor expectations, is completed on time and within budget, and is efficient and
cost-effective to operate and maintain.

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The level of systems engineering used for a project should be on a scale commensurate with
the scope, cost, and risk of the project. Complete the Intelligent Transportation Systems (ITS)
Systems Engineering Analysis Worksheet in Exhibit 1050-2, or a document with the same
information, for all federal-aid projects that include ITS elements. Completing the Worksheet
will meet the minimum requirements in 23 CFR 940.11 for systems engineering, determine the
project’s risk, and determine if a more in-depth systems engineering analysis is required. The
Worksheet and the four systems engineering documents outlined below are to be completed
with coordination between the project engineer and region Traffic Engineer.

As shown in the Worksheet, a more in-depth analysis requires that the following four
documents be completed and used to implement the project. These documents are produced
as the result of the steps in the systems engineering process.

1. Concept of Operations: This document defines the problem, the project’s goals, stakeholder
needs and expectations, constraints, and the way the ITS system is required to operate and
be maintained.

2. System Requirements: This document contains specifications of what the system is required
to do, how well it is required to do it, and under what conditions. These requirements are
based on the goals, stakeholder needs and expectations, constraints, and operation and
maintenance requirements documented in the Concept of Operations.

3. System Verification Plan: This document describes how the agency will verify that the
system being built meets the requirements in the System Requirements document. The
agency will implement the System Verification Plan to ensure all system requirements are
verified before it accepts the system.

4. System Validation Plan: This document describes how the agency will assess the system’s
performance against the goals, stakeholder needs and expectations, constraints, and
operation and maintenance requirements documented in the Concept of Operations. The
goal is for the agency to understand and review the strengths and weaknesses of the system
and identify any new opportunities and needs if appropriate. The agency will implement the
System Validation Plan after it accepts the system. This evaluation sets the stage for the
next time the system/project is changed or expanded.

For specific guidance on developing the four systems engineering plans listed above, see the
plan templates in the USDOT/CalTrans document, Systems Engineering Guidebook for Intelligent
Transportation Systems, Version 3, November 2009. Pertinent page numbers include:
• Concept of Operations Template: Page 254
• System Requirements Template: Page 257
• Verification Documents Plan Template: Page 269
• Validation Documents Plan Template: Page 278
For Adaptive Signal Control Technology Projects (ASCT) using the latest edition of the USDOT
Model Systems Engineering Documents for Adaptive Signal Control Technology (ASCT)
Systems, FHWA-HOP-11-027, August 2012, is required.

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Intelligent Transportation Systems Chapter 1050

As each phase of an ITS project is completed, a report is to be submitted by the Project Engineer
to the region Traffic Engineer describing how the project is meeting the requirements outlined
in the above systems engineering plans. Approvals for ITS projects are dependent upon project
complexity and cost. (See Chapter 300 for ITS project approval requirements.)

Systems engineering costs are to be estimated and incorporated into the construction
engineering (CE) and project engineering (PE) portions of the construction estimate.

For further project development guidance related to procurement and administration of

Federal-Aid Intelligent Transportation System (ITS) contracts, see 1050.04.

1050.03(1) Systems Engineering Process “V” Diagram

The systems engineering process contains a number of steps that are not included in a
traditional project delivery process. The systems engineering process is often referred to as the
“V” diagram (see Exhibit 1050-1). An ITS project begins on the left side of the “V” and progresses
down the left side and then up the right side. Then the project is evaluated by validating and
verifying the elements on the right side of the “V” with the elements on the left side.

The Federal Highway Administration (FHWA) and WSDOT are in agreement that, for project
development and delivery, the most critical portions of the systems engineering process are
the Concept of Operations; System Requirements; System Verification; and System Validation.
As a result, the Intelligent Transportation Systems (ITS) Systems Engineering Analysis Worksheet
in Exhibit 1050-2 is focused on these core areas.

Exhibit 1050-1 Systems Engineering Process “V” Diagram

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1050.04 FHWA Washington Division ITS Project Contracting Guidance

1050.04(1) Purpose
The purpose of this document is to provide basic guidance related to the procurement and
administration of Federal-Aid ITS contracts.

1050.04(2) Scope
This document is intended to be used by the FHWA Washington Division Office, WSDOT, and
local agencies as a guide on the proper types of procurement methods for various types of ITS
projects. This guidance is not all-encompassing, as ITS projects can vary significantly in scope.
However, it should provide adequate information to address a majority of situations. Specific
questions about an individual ITS project should be directed to the Washington Division Office.

1050.04(3) Construction versus Non-Construction

ITS improvements may be incorporated as part of a traditional federal-aid construction contract,
or the contracting agency may elect to procure ITS services under a separate contract (i.e.,
stand-alone ITS projects). When procured as a separate contract, the scope of an ITS contract
will determine the applicability of federal procurement requirements. Title 23 United States
Code 101(a)(4) provides a broad definition for construction for federal-aid eligibility purposes.
FHWA generally interprets the definition broadly, resulting in many types of projects being
classified as construction. Very simply, a contract that incurs costs incidental to the construction
or reconstruction of a highway, including improvements that directly facilitate and control traffic
flow (e.g., traffic control systems) are by definition construction contracts. This includes
rehabilitation of an existing physical ITS infrastructure. Construction contracts must follow
the regulatory requirements of 23 CFR 635 or 23 CFR 636 in the case of Design-Build.

Non-construction-type ITS contracts will be either Engineering Contracts or Service Contracts.

Engineering is defined as professional services of an engineering nature as defined by state law.
If the ITS contract primarily involves engineering, then qualifications-based selection (QBS)
procedures, in compliance with the Brooks Act, must be followed. Service contracts (non-
construction, non-engineering in nature) are to be procured in accordance with the Common
Rule for Grants and Cooperative Agreements to States and Local Governments found at 49 CFR
18.36.

1050.04(4) Types of ITS Projects

Stand-alone ITS projects can generally be categorized into one of the following types of ITS
projects: (1) planning/research, (2) preliminary engineering/project development, (3) software
development/system integration, (4) system deployments, (5) traditional construction, and
(6) operations and maintenance. All Federal-Aid ITS projects, regardless of the type, are
directed in 23 CFR 940 to follow a systems engineering process.

Exhibit 1050-3 provides further information about each of these ITS project types.

1050.05 Documentation
Include all ITS systems engineering documentation in the Design Documentation Package (DDP).
All systems engineering documentation requires region Traffic Engineer approval.

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Exhibit 1050-2 Intelligent Transportation Systems (ITS) Systems Engineering Analysis Worksheet

Intelligent Transportation Systems

Systems Engineering Analysis Worksheet

This worksheet, or a document with the same information, must be completed for all federal-aid
projects that include Intelligent Transportation Systems (ITS) elements. This worksheet must be
completed prior to submitting a construction authorization request and must be kept in the project
file for the entire document retention period of the project. If Concept of Operations, System
Requirements, Verification Plan, and Validation Plan documents are required for the project, as
determined by this spreadsheet, these documents must be submitted for review prior to submitting
a construction authorization request and must be kept in the project file for the entire document
retention period.

1. Project Name: Click here to enter text.

2. Contract Number: Click here to enter text.

3. Total project cost (includes preliminary engineering/design, right of way, and

construction phases): Click here to enter text.

4. Amount of total project cost for ITS elements: Click here to enter text.

5. Will this project implement a new or expand an existing adaptive signal control
technology (ASCT) system?
☐ Yes FHWA and WSDOT consider the project to be high risk. Four additional systems
engineering documents (Concept of Operations, System Requirements,
Verification Plan, and Validation Plan) are required. (See definitions in 1050.03
Systems Engineering.) These documents must be produced using the latest
edition of the USDOT Model Systems Engineering Documents for Adaptive Signal
Control Technology (ASCT) Systems, FHWA-HOP-11-027, August 2012. Please
skip questions 6 and 7.
☐ No

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Exhibit 1050-2 Intelligent Transportation Systems (ITS) Systems Engineering Analysis Worksheet (continued)

6. Select which of the following items, if any, apply to this project:

☐ The project includes new and unproven hardware and/or communications technology
that is considered “cutting edge” or not in common use. This could include custom-
developed or unproven commercial-off-the-shelf (COTS) technology that has not been
used by the agency previously. Please explain why you selected or did not select this
item.
Click here to enter text.

☐ The project will add new software that will be custom developed for this project or will
make major modifications to existing custom-developed software. Please explain why
you selected or did not select this item.
Click here to enter text.

☐ The project will add new interfaces to systems operated or maintained by other
agencies. Please explain why you selected or did not select this item.
Click here to enter text.

☐ The project will develop new system requirements or require revisions to existing
system requirements that are not well understood within the agency and/or well
documented at this time. These system requirements will be included in a request for
proposal, or plans, specifications, and estimate bid document package. Therefore, it will
require significant stakeholder involvement and/or technical expertise to develop these
items during the project delivery process. Please explain why you selected or did not
select this item.
Click here to enter text.

☐ Multiple agencies will be responsible for one or more aspects of the project design,
construction, deployment, and/or the ongoing operations and maintenance of the
system. Please explain why you selected or did not select this item.
Click here to enter text.

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Exhibit 1050-2 Intelligent Transportation Systems (ITS) Systems Engineering Analysis Worksheet (continued)

7. If you answered yes to any of the items in question 6, FHWA and WSDOT consider the
project to be high risk. See the following table for additional requirements.

Project Total Project Cost for ITS Elements

Risk Level Less than $1,000,000[3] Equal or Greater than $1,000,000[3]
High-Risk Additional systems engineering Additional systems engineering
ITS documents (Concept of Operations, documents (Concept of Operations,
System Requirements, Verification System Requirements, Verification Plan,
Plan, and Validation Plan)[2] are and Validation Plan)[2] are required.
recommended.[1]

Notes:
[1] A decision not to complete the additional systems engineering documents for high-risk
projects that have less than $1,000,000 of ITS elements requires FHWA concurrence
prior to submitting a construction authorization request.
[2] See definitions in 1050.03, Systems Engineering.
[3] Use the amount from question 4.

8. What is the name of the regional ITS architecture and which portions of the architecture will
be implemented? Is the project consistent with the architecture? Are revisions to the
architecture required? Also, which user services, physical subsystem elements, information
flows, and market/service packages will be completed, and how will these pieces be part of
the architecture?
Click here to enter text.

9. Identify the participating agencies, their roles and responsibilities, and the concept of
operations. For the elements and market/service packages to be implemented, define the
high-level operations of the system. This includes where the system will be used, its
performance parameters, its life cycle, and who will operate and maintain it. Discuss the
established requirements or agreements on information sharing and traffic device control
responsibilities. The regional ITS architecture operational concept is a good starting point for
discussion.

If this is a high-risk project and a more extensive Concept of Operations document is being
prepared for this project (see question 7), this answer can be a simple reference to that
document.
Click here to enter text.

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Exhibit 1050-2 Intelligent Transportation Systems (ITS) Systems Engineering Analysis Worksheet (continued)

10. Define the system requirements. Based on the concept of operations, define the “what”
and not the “how” of the system. Define the detailed requirements for eventual detailed
design. The applicable high-level functional requirements from the regional architecture
are a good starting point for discussion. A review of the requirements by the project
stakeholders is recommended.

If this is a high-risk project, and a more extensive System Requirements document is being
prepared for this project (see question 7), this answer can be a simple reference to that
document.
Click here to enter text.

11. Provide an analysis of alternative system configurations and technology options to meet
requirements. This analysis should outline the strengths and weaknesses, technical
feasibility, institutional compatibility, and life cycle costs of each alternative. The project
stakeholders should have had input in choosing the preferred solution.
Click here to enter text.

12. Identify procurement/contracting options. Since there are different procurement methods
for different types of projects, the decision regarding the best procurement option should
consider the level of agency participation, compatibility with existing procurement
methods, the role of the system integrator, and life cycle costs. Some options to consider
include: consultant design/low-bid contractor, systems manager, systems integrator, task
order, and design/build.

If the ITS portions of the project significantly meet the definition of construction, then
construction by low-bid contract would be used. Non-construction ITS portions of the
project, such as services for software development, systems integration, systems
deployment, systems management, or design, will be either engineering or service
contracts. In these cases, a qualifications-based selection (QBS) or best value procurement
may be more appropriate. For guidance on procurement options for ASCT systems, refer to
Pages 15-20 of USDOT’s Model Systems Engineering Documents for Adaptive Signal Control
Technology (ASCT) Systems, FHWA-HOP-11-027, August 2012.
Click here to enter text.

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Exhibit 1050-2 Intelligent Transportation Systems (ITS) Systems Engineering Analysis Worksheet (continued)

13. Identify the applicable ITS standards and testing procedures. Include documentation on
which standards will be incorporated into the system design. Also, include justification for
any applicable standards not incorporated. The standards discussion in the regional
architecture is a good starting point for discussion.
Click here to enter text.

14. Outline the procedures and resources necessary for operations and management of the
system. In addition to the concept of operations, document any internal policies or
procedures necessary to recognize and incorporate the new system into the current
operations and decision-making processes. Also, resources necessary to support continued
operations, including staffing and training, must be recognized early and be provided for.
Such resources must also be provided to support necessary maintenance and upkeep to
ensure continued system viability.
Click here to enter text.

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Chapter 1050 Intelligent Transportation Systems

Exhibit 1050-3 FHWA Washington Division – ITS Project Contracting Guidance

ITS
Project Description Examples
Type
Planning/Research

Generally, involves studies that research new concepts • Regional ITS architecture development and
or develop plans or procedures at a broader agency- or maintenance
region-wide level. These are generally not construction • Regional Concept of Operation
and are often done by agency personnel. • Traffic incident management planning
• Standards testing and specification development
• Public outreach and communication

• Scoping/field surveys
Engineering/Project

Generally, a project, or phase of a larger project, that

leads to some type of ITS deployment/construction. • Project-level Concept of Operation
Development
Preliminary

Typically involve some type of service or engineering • Environmental Review

contact, or work done by agency personnel, and are • Development of RFPs
generally not considered construction. • Development of PS&Es
• Evaluation of technology, networking, systems
architecture alternatives

Generally, involves projects that develop new or • Traffic Management Center (TMC) central
Development/System

upgraded ITS-related software or involve integrating ITS software design, development, installation
Integration

services and equipment. These are typically not • Modifying existing central system software
Software

construction and often fall under a service contract. to communicate with new field equipment
• Incorporation of device control software into
central systems
• Acceptance testing and configuration
management

Generally, includes total system implementation • Road-weather information systems (RWIS)

System Deployments

involving design, equipment, computer systems, • Surveillance camera procurement and

telecommunications, and integration. Contracts are installation on existing poles (non-construction
often non-construction in nature, depending on the when limited in scope)
amount and type of field work relative to the overall • Non-intrusive sensor procurement and
project. These types of projects will often be the least installation on existing poles (non-construction
cut-and-dried in terms of the appropriate contracting when limited in scope)
method. • Adaptive Signal Control Systems

Typical construction projects involving considerable • Installation of variable message signs

Traditional Construction

installation of equipment or work in the field. Design-Bid- • Installation of poles, controller cabinets,
Build (low bid) or Design-Build contracting are foundations, guardrail, gantries
appropriate for this type of work. • Installation of radio towers and civil
infrastructure for wireless systems
• Installation of tolling field equipment (tag
readers, video cameras, etc.)
• Installation of underground infrastructure
(trenching, cable installation, etc.)
Maintenance

Ongoing operations and/or maintenance of ITS services, • Operating costs for traffic monitoring,
Operations/

software, and equipment. Typically is a service contract management, control systems (e.g., rent,
(non-construction). communications, labor, utilities)
• Preventative maintenance

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Intelligent Transportation Systems Chapter 1050

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Chapter 1100 Practical Design
1100.01 General
1100.02 Practical Design Procedure
1100.03 Community Engagement
1100.04 Advisory Team
1100.05 Need and Performance Identification
1100.06 Context Identification
1100.07 Design Control Selection
1100.08 Alternative Formulation and Evaluation
1100.09 Design Element Selection and Dimensions
1100.10 Documentation Tools
1100.11 References

1100.01 General
The Washington State Department of Transportation (WSDOT) is committed to context-
appropriate, multimodal, performance-based designs. WSDOT’s goal is to optimize existing
system capacity and safety through better interconnectivity of all transportation modes.
Community engagement is an essential element.

This chapter provides an overview of the practical design approach that WSDOT uses to make
project decisions. The remaining chapters in Division 11 provide specific design policy details for
each procedural step. WSDOT’s practical design approach is context-appropriate, multi-modal
and performance-based. Practical design utilizes a collaborative approach, design flexibility, and
a high likelihood of variable solutions. As a result, WSDOT’s practical design finds consistency
through the procedural process applied rather than pre-determined outcomes for projects.

This chapter provides:

 An overview of the WSDOT Practical Solutions initiative.
 An overview of the practical design process.
 Information regarding the importance of design control selection.

1100.01(1) Practical Solutions

Practical Solutions includes practical solutions planning and practical design, as described in
Executive Order (EO) E 1090.

Practical Solutions enables more flexible and sustainable transportation investment decisions. It
encourages this by: (1) increasing the focus on addressing identified performance needs
throughout all phases of development, and (2) engaging local partners and stakeholders at the
earliest stages of scope definition to account for their input at the right stage of the
development process. Practical Solutions includes one or a combination of strategies, including,
but not limited to, operational improvements, off-system solutions, transportation demand
management, and incremental strategic capital solutions.
1100.01(1)(a) Practical Solutions Planning

Practical Solutions planning is an approach to making planning decisions that considers a variety
of conceptual strategies to achieve the desired system performance targets for the lowest cost.

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Practical Design Chapter 1100

Central to practical solutions planning is a process that identifies regional and corridor
performance areas, engages communities to ascertain local contexts and needs, and applies
methods to evaluate and implement short- and long-term solutions.

The outcome of practical solutions planning is a recommended set of multimodal strategies that
are cost-effective and balance the goals and objectives of state and local needs. WSDOT’s
corridor sketch initiative and planning studies inform practical solutions through the following:
 Identify performance gaps for a corridor segment, now and in the future.
 Identify potential strategies to address the gaps.
 Integrate inputs from partners that support corridor segment performance.
 Define context and corridor variables.

Identify and rank demand management and operational improvements first, then consider
capital solutions. Note that Executive Order (EO) E 1090 instructs that the solution may or may
not be on a state corridor.
1100.01(1)(b) Practical Design

Practical design focuses on the specific problem or problems identified during the planning and
scoping process. This performance-based approach looks for lower-cost solutions that meet
outcomes that WSDOT, collaborating agencies, communities, and stakeholders have identified.
Practical design is a fundamental component to the Vision, Mission, Values, Goals, and Reforms
identified in Results WSDOT, the department’s Strategic Plan. The primary objectives of the
practical design approach are: (1) focusing on project need(s), and (2) seeking the most
reasonable low-cost solution to meet that need(s).

Practical design allows flexibility and encourages innovation. Practical design considers
incremental solutions to address uncertainties in future scenarios. Practical design can be
applied at all phases of project development; however, it is most effective at the scoping level or
earlier, where key decisions are made as to what design controls and elements are affected by
alternatives and how they can best be configured to meet the project objectives.

With practical design, decision-making focuses on the maximum benefit to the system, rather
than the maximum benefit to the project.

1100.02 Practical Design Procedure

Practical design begins when a location under evaluation moves from a discussion of strategies
to one of potential solutions within those strategies. The beginning of the practical design
approach occurs when the scoping phase requires a Basis of Design (BOD), or when the
preliminary engineering phase for a funded project initiates. In each of these situations,
practical design procedures apply whether or not practical solutions planning has occurred.

WSDOT’s practical design process consists of seven primary procedural steps:

1. Assemble a project advisory team as needed (see 1100.04).
2. Clearly identify the baseline need. Define it in terms of performance, contributing factors,
and underlying reasons for the baseline need (see Chapter 1101).
3. Identify the land use and transportation context (which includes environmental use and
constraints) for the location (see Chapter 1102).

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Chapter 1100 Practical Design

4. Select design controls compatible with the context (see Chapter 1103).
5. Formulate and evaluate potential alternatives that resolve the baseline need for the
selected context and design controls (see Chapter 1104).
6. Select design elements that will be included in the alternatives (see Chapter 1105).
7. Determine design element dimensions consistent with performance needs, context, and
design controls (see Chapter 1106).

The Basis of Design (BOD) documents the outcomes of applying these procedural steps. It also
serves as a management tool throughout the design phase, to keep a project team focused on
the baseline performance need and agreed performance trade-offs in order to prevent scope
creep. During the design phase, a BOD is required on all projects unless design elements are not
changed (see exceptions in 1100.10). During the scoping phase, a BOD is only required as
determined by the Capital Program Development and Management (CPDM) Office. See
1100.10(1) for further information about the BOD.

1100.03 Community Engagement

WSDOT has a strategic goal of engaging the community in order to strengthen partnerships,
increase credibility, drive priorities, and inform decision-making. Community input informs the
project development process from planning to design. Engaging with the community helps us
more fully understand:
 Performance issues and gaps
 Context identity
 Local environmental issues
 Modal priorities and needs

WSDOT encourages recognition of individual community contexts, values, and needs in

developing transportation solutions. We do so in order to enhance public trust and develop
targeted designs that meet the performance needs of the state, regional, and local
transportation systems. – Executive Order 1096

Use the WSDOT Community Engagement Plan and document the findings of community
engagement efforts (see 1100.10(5)).

1100.04 Advisory Team

Teams deliver projects. Collaborative decisions contribute to successful project delivery.
Collaboration emphasizes context sensitive design as part of WSDOT’s approach. The practical
design approach is a team approach that involves external and internal stakeholders providing
consent-based outcomes early in project development. This is consistent with WSDOT Executive
Order 1096 - WSDOT 2015-17: Agency Emphasis and Expectations and Executive Order 1028 –
Context Sensitive Solutions. The advisory team is a collaborative body that provides
recommendations to the WSDOT project manager and engineer of record, specifically in these
areas:
 Need identification (including performance metrics and targets)
 Context identification
 Design control selection
 Alternative formulation

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Practical Design Chapter 1100

 Performance trade-off decision preferences (including weighing environmental

constraints and regulatory issues)
 Alternative evaluation

The Engineer of Record, or project manager, convenes an advisory team that has the skills,
knowledge, and responsibilities needed for design decision-making; including planning, project
development, environment, active transportation, and context sensitive design. Include WSDOT
members on the advisory team who have positional or delegated authority to make decisions
associated with the areas outlined in this chapter.

The project manager and project team consider recommendations offered by the advisory team.
The project manager decides which recommendations, if any, will be included in the project and
informs the advisory team, providing an opportunity for feedback. Document recommendations
and their treatment to the Basis of Design prior to its approval.

The project manager has discretion in how to work with internal and external stakeholders in
documenting decisions. For more information on organizing, managing, and collaborating with
advisory teams, see the WSDOT Project Management Guide:
 www.wsdot.wa.gov/projects/projectmgmt/onlineguide/preconstructioninitiatealign

1100.05 Need and Performance Identification

The most fundamental function of practical design is to focus on the primary reason a location is
under evaluation. Ask why there is a project under consideration at this location, and identify
the specific need. If it is a mobility project, why is there a mobility need and what is specifically
contributing to that need?

WSDOT’s practical design approach requires that the need be translated into specific
performance metrics and that targets be selected to be achieved by the design. A contributing
factors analysis (see Chapter 1101) refines focus in order to resolve the specific performance
problems and helps define the potential scope of project alternatives.

Chapter 1101 provides guidance for identifying project performance needs. Understanding
performance and associated performance terms is critical to the application of Chapter 1101.
See the guidance document Performance Based Design before proceeding with application of
Chapter 1101. Direct link to guidance document:
 www.wsdot.wa.gov/publications/fulltext/design/ASDE/Practical_Design.pdf

1100.06 Context Identification

Context identification refers to understanding the characteristics, activities, and functions within
a geographical area. WSDOT is committed to providing context sensitive solutions (see E 1028),
and context identification is key to implementing this goal. WSDOT’s context identification
process involves two interrelated context facets: land use and transportation. Context
identification also considers existing and future contexts. Chapter 1102 provides guidance for
determining context.

1100.07 Design Control Selection

Design controls create significant boundaries and have significant influence on design. WSDOT
uses five primary design controls:

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Chapter 1100 Practical Design

1. Design Year
2. Modal Priority
3. Access Control
4. Design Speed
5. Terrain Classification

Chapter 1103 presents guidance related to choosing design controls.

1100.08 Alternative Formulation and Evaluation

Under practical design, the goal is to develop a solution for the baseline need at the lowest cost.
However, it is critical to understand how the solution affects other known or identified needs,
termed “contextual needs.” This requires consideration of multimodal solutions. Chapter 1101
provides a discussion on baseline and contextual performance needs, and Chapter 1104
discusses using these needs to develop and evaluate alternatives.

Practical Solutions requires consideration of operational and

demand management strategies prior to implementing a
capital strategy. The intent is to find low-cost solutions
before making large capital investments.

In some cases, the planning phase will have identified a

strategy based on practical solutions planning. Focusing on
the preferred strategy can help guide the development of
alternative solutions. The guidance document Alternative
Strategies and Solutions discusses primary strategies and
examples of solutions within those strategies.

Design Support guidance document:  http://www.wsdot.wa.gov/Design/Support.htm

Direct link to guidance document:
 www.wsdot.wa.gov/publications/fulltext/design/ASDE/Practical_Design.pdf

1100.09 Design Element Selection and Dimensions

Design element selection is based entirely on the alternative selected to resolve the baseline
need and balance performance trade-offs. Chapter 1105 provides instruction for design element
selection. Chapter 1106 provides information related to choosing dimensions for design
elements.

1100.10 Documentation Tools

Basis of Design (BOD), Basis of Estimate (BOE), Design Parameter Sheets, and Alternative
Comparison Tables are all documentation tools used to record decisions and analyses needed in
development of a solution that is consistent with WSDOT’s practical design approach. The tools
can be found at:  http://www.wsdot.wa.gov/Design/Support.htm

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Practical Design Chapter 1100

1100.10(1) Basis of Design

The BOD organizes information around the practical design procedural steps (see 1100.02)
necessary to support WSDOT’s practical design approach. It provides a template for
documenting each step in the process. The BOD includes the following information and sections:
 Planning Document Summary
 General Project Information
 Section 1 – Project Needs
 Section 2 – Context
 Section 3 – Design Controls
 Section 4 – Alternatives Analysis
 Section 5 – Design Element Selection

Exhibit 1100-1 shows the major activities associated with WSDOT’s practical design approach
and corresponding Design Manual chapters and Basis of Design sections.

When using a BOD, start as early as possible. During planning or scoping, a BOD may be only
partially completed. Information documented on the BOD provides an opportunity for greater
consistency between strategies developed in planning and solutions developed in scoping and
design. Information documented in the BOD comes through use of consent-based
recommendations (see Section 1100.04).

Contact the region Program Management regarding the need to initiate a BOD during the
project-scoping phase. Since the BOD is ultimately a document that supports design decisions,
the approval of a BOD, which ideally takes place at 30% design level or earlier, is a part of, and
included in, the project Design Approval process (see Chapter 300).

Basis of Design:  www.wsdot.wa.gov/Design/Support.htm

1100.10(1)(a) Basis of Design Exemptions

See 1100.02 for guidance regarding when a BOD is required for scoping projects. For design-
phase projects, a BOD supports design decisions and is required on all projects where one or
more design elements are changed (see Chapter 1105). Exceptions are listed below.
1100.10(1)(a)(1) All Projects

If the only design elements changed by the project are listed in Exhibit 1105-1, a Basis of Design
(BOD) may not be required. The Assistant State Design Engineer (ASDE) shall concur with the
request to exempt the BOD requirement. Submit a request, by email, for an exemption from the
BOD requirement. The request should explain the unique circumstances that make use of the
BOD unnecessary. Each request is evaluated on a case-by-case basis. If a BOD has been prepared
for the project and no design elements were changed, an ASDE approval of the BOD is not
required.
1100.10(1)(a)(2) Preservation Projects

A Basis of Design form is not required for Preservation projects if the only design elements
changed are listed in Chapter 1120, and the criteria/guidance provided in Chapter 1120 is
followed.

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Chapter 1100 Practical Design

1100.10(1)(a)(3) Safety Projects

Safety projects (developed under the I-2 funding program) may not require a BOD even though
design elements are changed. The Assistant State Design Engineer (ASDE) shall provide
concurrence to exempt the project from the BOD requirement. Submit exemption requests to
the ASDE by email explaining why an exemption is applicable. The request should explain the
unique circumstances that make use of the BOD unnecessary. Exemption requests are evaluated
on a case-by-case basis.

Circumstances that may contribute to a decision to exempt a safety project from the need to
prepare a BOD include:
 A programmatic project endorsed by the WSDOT Highway Safety Panel (e.g.
Intersection Improvement Program ISIP treatments, Rumble Strips, etc.)
 A Collision Analysis Report (CAR) was approved by the WSDOT Highway Safety Panel
AND:
The CAR clearly identifies the project need.
The CAR compared and rated alternatives.

1100.10(2) Basis of Estimate

A Basis of Estimate is required for all project estimates, and is updated throughout all phases of
project development. Refer to the Cost Estimating Manual for WSDOT Projects for additional
information on estimating and the Basis of Estimate.

1100.10(3) Alternatives Comparison Table

The Alternative Comparison Table (ACT) provides solutions evaluated in accordance with
WSDOT’s Practical Solutions approach. This table allows comparison of alternatives to identify
the optimum solution. The table enables discussions of performance trade-offs. The Alternative
Comparison Table is supplemental documentation for Section 4 of the BOD. Alternative
Comparison Table:  www.wsdot.wa.gov/Design/Support.htm.

1100.10(4) Design Parameter Sheets

The Design Parameter Sheets document the dimensions selected for the various design
elements selected and noted in Section 5 of the Basis of Design. Design Parameter Sheet
template:  www.wsdot.wa.gov/Design/Support.htm

1100.10(5) Documenting Community Engagement

Community engagement is a fundamental component of WSDOT’s Practical Solutions strategy,
and key to practical design implementation. Community engagement will be consistent with the
WSDOT Community Engagement Plan (see  www.wsdot.wa.gov/planning/)

Document community engagement for all projects. There is no strict format for this.

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Practical Design Chapter 1100

1100.11 References

1100.11(1) Federal/State Directives, Laws, and Codes

Revised Code of Washington (RCW) 47.04.280 – Transportation system policy goals

Revised Code of Washington (RCW) 47.05.010 – The statement of purpose for priority
programming of transportation projects

Secretary’s Executive Order 1090 – Moving Washington Forward: Practical Solutions

Secretary’s Executive Order 1096 – WSDOT 2015-17: Agency Emphasis and Expectations

Secretary’s Executive Order 1028 – Context Sensitive Solution

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Chapter 1100 Practical Design

Exhibit 1100-1 Basis of Design Flowchart

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Practical Design Chapter 1100

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Chapter 1101 Need Identification
1101.01 General
1101.02 Baseline Needs
1101.03 Contextual Needs
1101.04 Contributing Factors Analysis
1101.05 Project Need Statement
1101.06 Documentation
1101.07 References

1101.01 General
Practical design starts with identification of issues associated with the performance of a
transportation facility. First, one or more project needs associated with these issues are
identified. These project needs represent the gap in performance between the existing and
desired state. Once they are identified, a project need statement is then developed which
expresses only the most fundamental causes of these performance gaps.

This chapter provides:

 Instruction on the different types of needs—baseline and contextual.
 A method to diagnose and analyze the contributing factors of the identified need.
 Instruction on how to determine performance metrics and targets for each of the
identified needs.
 How to develop project need statements.

1101.02 Baseline Needs

A baseline need is the primary reason a project has been proposed at a location. The baseline
need usually evolves from a WSDOT planning and/or priority programming process. There can
be more than one baseline need such as when an agency partners with WSDOT on a project and
the partner’s need becomes another baseline need. It is important to consider the needs of all
mode users.

Example: A local agency desires to fund a revitalization project for a community bordering a
state highway. The local agency’s baseline need in this case is the local land use’s economic
vitality. If WSDOT also happens to have a prioritized and funded baseline need at the same
location, and the two parties decide to partner in a combined project, that project will have
at least two baseline needs. The two parties will work to develop solutions compatible for
both baseline needs.

To determine, develop, and refine the project’s baseline need(s), examine the conditions
surrounding the original project identification, which was completed in the priority
programming phase.

After developing and refining the baseline need(s), define the baseline performance metrics.
(see 1101.02(1)) and determine the baseline need targets (see 1101.02(2)).

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Need Identification Chapter 1101

1101.02(1) Baseline Performance Metrics of the Baseline Need(s)

Baseline performance metrics are those “measurables” used to check that the project satisfies
the need(s). Baseline performance metrics are also used in the development of the project need
statement. Project alternatives must address the identified baseline performance metric(s).

Threshold performance metrics are used in the priority programming process to screen the full
state network under each performance category (for further information on threshold
performance metrics and performance categories, see the guidance document Performance-
Based Decisions:  www.wsdot.wa.gov/Design/Support.htm). The baseline performance
metric for preservation category projects is predetermined, and is the same as the threshold
performance metrics determined by Subject Matter Experts (SMEs) and HQ Capital Program
Development and Management (CPDM) Office.

The baseline performance metrics for a mobility or economic vitality category project may be
different from the threshold performance metrics. However, the baseline metric chosen is to be
consistent with the priority programming performance category that identified the location to
be evaluated.

Example: A routinely congested corridor has been screened to identify locations with a
potential mobility performance gap. Screening used a threshold performance metric of
estimated operations at 70% of posted speed during the peak hour. After considering the
context of the location, and the relevance of the threshold performance metric to the site
specific conditions and operations, the advisory team recommends that travel time
reliability is a more appropriate metric for the location.

WSDOT’s practical design approach is committed to multimodal safety as identified in

Washington State’s Strategic Safety Plan (see  www.targetzero.com/plan.htm). To meet this
commitment, projects are required to include a baseline performance metric for evaluating the
number of fatal and serious injury crashes in safety, mobility and economic vitality category
projects. Other safety metrics to address the specific community or partnering agency needs
may be included as contextual needs.

Safety projects are expected to continue project development as directed by the Multimodal
Safety Executive Committee (MSEC), and described in the Safety Scoping Flowchart and Chapter
321.

Other projects are to coordinate up front with the HQ Safety Technical Group to determine the
scale and scope of crash analyses appropriate for different types and sizes of projects. For
additional information see Chapter 321.

1101.02(2) Baseline Performance Target

Performance targets are the outcome (or desired state) intended for a project. Use baseline
performance metrics and targets to compare alternative designs based on how well the
alternative meets the selected targets relative to their costs. Targets can be a single value or
range of values.

There may be situations where the targets cannot practicably be met by any alternative or
where there are unacceptable performance trade-offs in other performance categories. In these
situations it may be appropriate to accept performance trade-offs, in one of the other

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Chapter 1101 Need Identification

categories during the alternatives evaluation (see Chapter 1104), in order to balance competing
needs and outcomes. In other situations, it may be appropriate to refine the performance target
under consideration.

1101.03 Contextual Needs

Practical design requires that designers refrain from overdesigning the project by focusing the
solution on the baseline need or needs. In doing so, opportunities are provided by projects to
address other needs that may be identified through community engagement and/or increased
project knowledge and understanding. These other needs are classified as “contextual needs.”
A contextual need is any identified need that is not a baseline need. Potential sources of
contextual needs include:
 Performance gaps identified through the priority network screening that did not
prioritize under a statewide biennial prioritization and budget exercise, but still exist at
the project location.
 Needs identified through community engagement or identified by a partnering agency.
 Needs based on identified environmental regulations and constraints.
 Needs identified through coordination with WSDOT maintenance (see Chapter 301 for
additional information).
 Needs identified through increased knowledge of the project site and context.

Develop metrics for contextual needs to compare alternatives. Interpret and translate each
issue into a statement that is measureable, to the extent feasible. Contextual need metrics can
be either quantitative or qualitative.

1101.03(1) Use in Alternative Formulation and Evaluation

Contextual needs serve a different role than baseline needs. Baseline needs primarily shape the
alternatives developed, while contextual needs are important to the performance trade-offs
discussion (see Chapter 1104). Not all contextual needs identified need to be addressed by a
project. Contextual needs present opportunities for optimizing the design, provide for
partnerships and modes, and ultimately determine the most optimal project alternative (in
conjunction with SEPA/NEPA processes as discussed in Chapter 1104).

Whether a design alternative achieves a particular contextual performance target is a

consideration during the tradeoffs analysis. When no alternative adequately balances
performance, lower-cost countermeasures can be employed to help mitigate performance
issues and improve the viability of alternatives. Modifications to one or more design controls are
another approach that can be used to achieve performance targets (see Chapter 1103), without
significantly burdening the alternative with additional cost. If all alternatives fail to find an
acceptable performance balance targets may be refined. Performance targets are documented
and approved as part of the Basis of Design approval process.

1101.04 Contributing Factors Analysis

Contributing factors analysis (CFA) is a process by which subject matter experts on the advisory
team evaluate the contributing factors associated with performance gaps in order to identify the
root reasons for each gap. In the transportation field, contributing factors are any geometric,

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Need Identification Chapter 1101

operational, context-based, or human factor that can reasonably be attributed to a performance

need through data analysis and engineering judgment.

Practical design relies on CFA to find the root reason(s) a need exists, rather than focusing on a
symptom that may only temporarily or partially resolve the need.

Note: It is recognized that completely solving a problem may not be possible by a single
corrective action due to the number of contributing factors or because of constraints.

The CFA method will:

 Organize and identify multiple contributing factors and underlying root reasons.
 Formulate a number of potential countermeasures to solve the need as thoroughly and
efficiently as possible.

Diagnosis of contributing factors yields the best results when data is available for the analysis.
Comprehensive crash data, organized by travel mode, is important when considering safety
performance. In other performance categories, where quantitative data is not available,
qualitative analysis may be used to reveal the underlying contributing factor(s).

Contributing factor analysis is only required for evaluation of baseline performance needs.
However, it may be relevant to perform CFA for contextual performance metrics.

Diagnosing contributing factors using CFA is not necessarily a simple linear process. It’s possible
to find that a contributing factor identified by one discipline is the root cause of another
discipline’s contributing factor. In some cases, mapping the contributing factors in a network or
fishbone diagram can help identify these relationships more clearly (see the guidance document
Contributing Factors Analysis:  www.wsdot.wa.gov/Design/Support.htm).

1101.05 Project Need Statement

A project need statement (or statement of need) uses the baseline needs (see 1101.02) and
results of contributing factors analysis to succinctly describe the real root project need(s). The
objective is to provide a clear, accurate plain talk description of the root needs that will facilitate
the development of efficient, focused project alternatives. A need statement should:
 Identify the objective, in simple, direct terms.
 Identify the performance metric(s) involved.
 Include one or more quantifiable statements.
 Exclude any description or discussion of potential solutions.

Consider other processes applicable to their projects that may require need statements such as:
value engineering, NEPA/SEPA, and Access Revision Reports. Consider timing of these processes
as well as integration and alignment of the need statements with the processes required for the
project.

For more information and examples of need statements, see the guidance document Writing
Effective Needs Statement:  www.wsdot.wa.gov/Design/Support.htm

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Chapter 1101 Need Identification

1101.06 Documentation
Use the Basis of Design, Section 1, to document decision-making and conclusions associated
with project need identification.

Download The BOD here:  www.wsdot.wa.gov/Design/Support.htm

1101.07 References
Contributing Factors Analysis, WSDOT Guidance Document:
 www.wsdot.wa.gov/Design/Support.htm

Performance-Based Design, WSDOT Guidance Document:

 www.wsdot.wa.gov/Design/Support.htm

Writing Effective Needs Statement, WSDOT Guidance Document:

 www.wsdot.wa.gov/Design/Support.htm

Washington State’s Strategic Safety Plan:  www.targetzero.com/plan.htm

WSDOT Safety Scoping Flowchart:

 http://wwwi.wsdot.wa.gov/ppsc/pgmmgt/wwwi/PlanProg/Scoping/SafetyScopingProcessFlo
wChart.pdf

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Chapter 1102 Context Determination
1102.01 General Overview
1102.02 Land Use Context
1102.03 Transportation Context
1102.04 Documentation
1102.05 References

1102.01 General Overview

Context refers to the environmental, economic, and social features that influence livability and
travel characteristics. Context characteristics provide insight into the activities, functions, and
performance that can be influenced by the roadway design. Context also informs roadway
design, including the selection of design controls, such as target speed and modal priority, and
other design decisions.

For the purposes of transportation planning and design, WSDOT divides context into two
categories: land use and transportation. Each of these contexts is further defined and
categorized in this chapter. Note that context categories, and the information pertinent to
deriving them, may have been documented in a planning study.

The concepts and method described in this chapter are adapted from National Cooperative
Highway Research Program Report 855: “An Expanded Functional Classification System for
Highways and Streets” (see http://www.trb.org/NCHRP/Blurbs/176004.aspx).

1102.02 Land Use Context

This section describes the procedure for determining the land use context category on non-
freeway facilities. The guidance in this section does not apply for freeways (see Chapter 1232 for
the definition of a freeway). For freeways, Section 2 of the Basis of Design is used only to
document the urban/rural designation as listed for the route on the State Route Log.

On larger projects, more than one land use category may apply within project limits.

Step 1. Determine an initial land use context category (current state)

Land use context categories are described in detail in 1102.02(1). These categories represent
distinctive land use environments beyond simply “rural” and “urban” to help determine a more
accurate context. These categories influence roadway design, including determining appropriate
operating speeds, mobility and access demands, and modal users. The land use categories are:
 Rural
 Suburban
 Urban
 Urban Core

Use the following factors to determine your initial land use context category:
1. Land uses (primarily residential, commercial, industrial, and/or agricultural)
2. Density
3. Setbacks

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Context Determination Chapter 1102

Quantify these factors through an assessment of the area adjacent to the existing or planned
roadway (see Exhibit 1102-1).

Step 2. Determine an initial land use context category (future state)

Using the same factors and categories, consult with local agency staff, and review state,
regional, and local planning documents to consider and document potential or anticipated
changes to land use context. Sources of information include the local comprehensive plan,
WSDOT Highway System Plan, WSDOT corridor sketches, and WSDOT planning studies in the
corridor.
Exhibit 1102-1 Factors for Determining Initial Land Use Context

Factor Criteria
Land Use Land uses within ½ mi of roadway
Density Housing units / acre
Density Jobs / acre
Density Intersections per sq. mi.
Density Typical building height
Setback Typical building setback
Setback Parking (on street or off street)

Specific metrics guiding the use of these criteria in determining the initial land use context
category (both current and future) are provided on the WSDOT Design Office website.

Step 3. Select final land use context category (current and future state)

Once an initial land use category is determined, additional (primarily qualitative) considerations
are used to verify that the selected category is appropriate. Because data used in the initial
determination may be incomplete, conflicting, or difficult to interpret, it’s expected that
professional judgment is used to confirm the context result. Even when the overall assessment
is clear, discontinuities or transitions between categories may exist and require further
interpretation.

Confirm or make adjustments to the initial context category based on a qualitative analysis. Use
information gathered from consultations with local agency staff, as well as the project’s
community engagement processes, to validate a final determination about current and future
context. Information about topography, soil type, land value, population density, average
building square footage, visual assessments, aerial photos, zoning, and other local agency land
use data and/or maps may also be used in this step.

Document the process used to make this final context determination. Include the data used,
interdisciplinary input, and issues encountered and resolved in the process. Conclude with a
final land use context determination that confirms, or adjusts, the initial category(s) for the
project, and seek the endorsement of this final determination from the project advisory team
(see Chapter 1100).

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Chapter 1102 Context Determination

1102.02(1) Land Use Categories

The land use categories used to inform project design are described below.

1102.02(1)(a) Rural

The rural category ranges from no development (natural environment) to some light
development (structures), with sparse residential and other structures mostly associated with
farms. The land is primarily used for outdoor recreation, agriculture, farms, and/or resource
extraction. Occasionally non-incorporated communities will include a few residential and
commercial structures. Rural characteristics also include:
 No or very few pedestrians – except those locations used for outdoor recreation and
modal connections, and where socioeconomic factors suggest that walking is likely to
serve as an essential form of transportation
 Bicycle use mostly recreational– except for tourist destinations, modal connection
locations and between communities where bicycle commuters may be expected or
where socioeconomic factors suggest that bicycling is likely to serve as an essential
form of transportation.
 Low development density
 Isolated residential or commercial activities
 Commercial uses include general stores, restaurants, and gas stations, normally at
crossroads
 Setbacks for structures are usually large, except in the immediate vicinity of small
settlements
 Transit service availability is often absent or highly limited, but varies widely depending
on the jurisdiction. On-demand service is typically found to provide specialized
transportation services
1102.02(1)(b) Suburban

Locations classified as suburban include a diverse range of commercial and residential uses that
have a low or often, medium density. Suburban areas are usually (but not always) connected
and closely integrated with an urban area. The buildings tend to be multi-story with off-street
parking. Sidewalks are usually present and bicycle lanes may exist. These areas include mixed
use town centers, commercial corridors, and residential areas. Big box commercial and light
industrial uses are also common. The range of uses encompasses health services, light industrial
(and sometimes heavy industrial), quick-stop shops, gas stations, restaurants, and schools and
libraries. Suburban characteristics also include:
 Heavy reliance on passenger vehicles
 Transit may be present
 Residential areas may consist of single and/or multi-family structures
 Building and structure setbacks from the roadway vary from short to long
 May have well planned and arranged multi-uses that encourage walking and biking

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Context Determination Chapter 1102

 Planned multi-use clusters may integrate residential and commercial areas along with
schools and parks
 Some highways that fit this category may be designated by WSDOT as “Main Street
Highways” (see Appendix B: Identification of State Highways as Main Streets,
 http://www.wsdot.wa.gov/research/reports/fullreports/733.1.pdf.)

1102.02(1)(c) Urban

Urban locations are high density, consisting principally of multi-story and low to medium rise
structures for residential and commercial use. Areas usually exist for light and sometimes heavy
industrial use. Many structures accommodate mixed uses: commercial, residential, and parking.
Urban areas usually include prominent destinations with specialized structures for
entertainment, athletic and social events as well as conference centers and may serve as a Main
Street (see 1102.03(6)). Urban characteristics also include:
 Various government and public use structures exist that are accessed regularly
 Building setbacks are both short and long
 Streets normally have on-street parking
 Wide sidewalks and plazas accommodate more intense pedestrian traffic
 Bicycle lanes and transit corridors are frequently present
 Off-street parking includes multi-level structures that may be integrated with
commercial or residential uses
 Some highways that fit this category may be designated by WSDOT as “Main Street
Highways” (see Appendix B: Identification of State Highways as Main Streets

Due to the differences in developmental scale among urban areas as well as growth demand
urban-urban core, context boundaries change over time with the urban core area expanding in
high growth situations and possibly contracting in low or no growth situations.
1102.02(1)(d) Urban Core

Urban core locations include the highest level of density with its mixed residential and
commercial uses accommodated in high-rise structures. There is commonly on-street parking,
although it is usually time restricted. Most parking is in multi-level structures attached or
integrated with other structures. The area is accessible to automobiles, commercial delivery
vehicles, biking, walking, and public transit. Urban Core characteristics also include:
 Sidewalks and pedestrian plazas are present
 Bicycle facilities and transit corridors are common
 Typical land uses are mixed commercial, residential, with some government or similar
institutions present
 Commercial uses predominate, including financial and legal
 Structures (predominantly high rises) may have multiple uses
 With the highest land value of any category, setbacks from the street are small
 Some highways that fit this category may be designated by WSDOT as “Main Street
Highways” (see Appendix B: Identification of State Highways as Main Streets

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Chapter 1102 Context Determination

1102.03 Transportation Context

This section describes the procedure for determining the current and future transportation
context for the roadway. On larger projects, more than one transportation context may apply
within project limits. Network connections are also useful in understanding the transportation
context.

Each transportation context is to be described in terms of the following categories and

considerations:
 Roadway type
 Bicycle route type
 Pedestrian route type
 Freight route type
 Transit use considerations
 Complete streets and Main Street highways

Seek endorsement from the project advisory team (see Chapter 1100) for determinations of
these transportation context types and considerations, including input from local agency (local
jurisdictions and transit agencies) and stakeholders. Document determination of each of these
transportation contexts for both current and future states in Section 2 of the Basis of Design,
and carry these results forward into determination of modal compatibility and modal priority
(Chapter 1103).

Additional information supporting work described in this section is provided on the WSDOT
Design Office website.

1102.03(1) Roadway Type

The initial roadway type is defined by the designated functional classification on the WSDOT
State Route Log for the route as listed below for non-freeway facilities. A final roadway type
determination is based on an assessment of whether a different functional class description
(given below) corresponds better to the current and future state of the facility, compared to the
designated functional class for the facility. The future state is determined after an assessment of
the future modal route types described below. Justify the selection of a final roadway type
whether it is the same or different from the designated functional class.
Freeways (including Interstate freeways) are defined in Chapter 1232. These routes typically
are limited access facilities. The roadway type for freeways is freeway.

Roadway types for non-freeway facilities are described as follows.

 Principal Arterial – Corridors of regional importance connecting large centers of
activity. These routes may be limited access facilities.
 Minor Arterial – Corridors of regional or local importance connecting centers of
activity.
 Collector – Roadways of local importance providing connections between arterials and
local roads.
 Local – Roads with no regional importance for local circulation and access only

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Context Determination Chapter 1102

1102.03(2) Bicycle Route Type

Bicycle routes are categorized based on the purpose of the trip and the network connectivity a
facility provides. Use quantitative and qualitative information about bicycle connections
associated with the project location to determine the current and future bicycle route type
using one of these three classifications:
 Citywide Connector (CC) — The route is part of a citywide network, provides a
connection to major activity centers, or is a regional bike route stretching over several
miles that attracts a high volume of use, serving a primary commute or recreational
purpose. These routes are typically associated with arterials and collectors.
 Neighborhood Connector (NC) — The route provides a neighborhood or sub-area
connection, making connections to higher order facilities or more local activity centers,
such as neighborhood commercial centers. These routes are typically associated with
minor arterials and collectors.
 Local Connector (LC) — The route provides local connections of short lengths, providing
internal connections within neighborhoods, or linking neighborhoods to higher order
facilities. These routes are typically associated with collectors and local roads.

1102.03(3) Pedestrian Route Type

Pedestrian use is described in terms of estimated volumes (current and potential future). The
amount of pedestrian traffic impacts several factors, including pedestrian facility capacity,
vehicular delays at signalized intersections, and most importantly, the level of risk associated
from pedestrians in the travelled way. The four pedestrian route types are based on volume as
follows:
 P-1: rare or occasional use
 P-2: low volume – best measured in pedestrians per day
 P-3: medium volume - best measured in pedestrians per hour
 P-4: high volume - best in pedestrians per hour, where sub-hour peak periods are
typical

1102.03(4) Freight Route Type

Freight routes may not require significant additional facilities beyond those provided for other
motorized vehicles, if mobility and speeds of vehicular routes are consistent with freight
movement. Special design consideration is commonly related to the Freight and Goods
Transportation System classification. Document the classification for the project area.

Contact Rail, Freight, and Ports Division for help identifying freight classifications, industry needs
and truck operations.

Truck route classifications can be found here:

 http://www.wsdot.wa.gov/Freight/EconCorridors.htm

Additional information:  http://www.wsdot.wa.gov/freight/

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Chapter 1102 Context Determination

1102.03(5) Transit Use Considerations

Transit can provide service on any roadway type. The purposes of transit trips are similar to
those of automobile trips and include commuting, work related business, shopping, personal
errands, and social/recreational. The facilities and design considerations for transit uses depend
on the type of transit service being provided. Note that special design consideration is required
for projects that involve one or more of the following elements:
 Fixed route type: there are three primary types of fixed-route transit service, operating
along designated routes at set times (Local, Limited, and Express). If one of these
services exists on the project, determine the route type using criteria shown in the
illustration below and the following bullets:

Source: TRPC Report 165: Transit Capacity and Quality of Service Manual.

Local routes serve many stops along a route and emphasize access to transit over
speed.
Limited stop routes (also known as frequent routes, including bus rapid transit)
balance transit access with speed. These routes run frequently and serve higher
volume stops (e.g. major activity centers and transfer points).
Express routes emphasize speed over transit access, and are often used for longer
distance trips.

Note that in addition to fixed-route service, many agencies provide demand-response

paratransit services that provide specialized transportation services in both rural and
urban areas.
 Bus rapid transit or light rail
 Transit signal priority installation
 Planned transit facilities and routes
 In lane bus stops and/or potential bus pullouts
 Facilities for people with specialized transportation needs (e.g. hospitals, senior
centers, schools, transit-dependent communities, etc.)

When evaluating transit needs and the potential for transit to improve highway performance in
the project area, document relevant information or data about current transit capacity and
quality of service (as defined in the Transit Capacity and Quality of Service Manual) and current
and potential future use and travel markets. Include consideration for people walking and biking
to/from transit connections. Contact the Public Transportation Division for help or for more
information about identifying and coordinating with transit agencies and local jurisdictions that
serve the project area ( http://wwwi.wsdot.wa.gov/PubTran/).

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1102.03(6) Complete Streets and Main Street Highways

Complete street contexts consider all transportation modes and often require differing modal
priorities based on the existing land uses or may even consider multiple modes of equal priority.
Complete streets may be desirable in various land use contexts including urban core, urban,
suburban, small town, and even some rural contexts.

The Main Streets designation for highways is a point of reference and consideration when
documenting transportation context, and should be noted on the Basis of Design. Main Street
highways serve the aesthetic, social, economic, and environmental values in a larger community
setting in addition to transportation. They are set up as specific state route and milepost
designations.

See the Complete Streets and Main Street Highways Program document listed in Supporting
Information at the end of this chapter for more information. For the list of designated highways
see State Highways as Main Streets: A Study of Community Design and Visioning, Appendix B:
Identification of State Highways as Main Streets,
 http://www.wsdot.wa.gov/research/reports/fullreports/733.1.pdf.

1102.04 Documentation
Document the following in Section 2 of the Basis of Design:
 Land use category
 Roadway type
 Bicycle route type
 Pedestrian route type
 Freight route classification
 Transit use considerations
 Main Streets designation

Describe the process that was followed to reach these designations. If the work involved review
and verification of previous work, document that process as well. If characteristics vary within
project limits include the milepost ranges to which each of the designations apply.

The Context and Modal Accommodation Report is a template available for use in this
documentation process (see https://www.wsdot.wa.gov/design/support.htm).

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1102.05 References

1102.05(1) Federal/State Directives, Laws, and Codes

23 Code of Federal Regulations (CFR) 450, Subpart B, Statewide Transportation Planning

23 CFR 450, Subpart C, Metropolitan Transportation Planning and Programming

23 United States Code (USC) 134, Metropolitan Planning

23 USC 135, Statewide Planning

Revised Code of Washington (RCW) 35.58.2795, Public transportation systems – Six-year transit
plans

RCW 35.77.010(2) and RCW 36.81.121(2), Perpetual advanced six-year plans for coordinated
transportation program expenditures – Nonmotorized transportation – Railroad right-of-way

RCW 36.70A, Growth management – Planning by selected counties and cities

RCW 43.21C, State environmental policy

RCW 47.05, Priority programming for highway development

RCW 47.06, Statewide transportation planning

RCW 47.06B, Coordinating special needs transportation

Secretary’s Executive Order 1090 – Moving Washington Forward: Practical Solutions

Secretary’s Executive Order 1096 – WSDOT 2015-17: Agency Emphasis and Expectations

1102.05(2) Supporting Information

WSDOT References

Understanding Flexibility in Transportation Design – Washington, WA-RD 638.1, WSDOT, 2005

 http://www.wsdot.wa.gov/research/reports/600/638.1.htm

Complete Streets and Main Street Highways Program, WSDOT, 2011

 https://www.wsdot.wa.gov/research/reports/fullreports/780.1.pdf

State Highways as Main Streets: A Study of Community Design and Visioning, WSDOT, 2009
Appendix B: Identification of State Highways as Main Streets
 http://www.wsdot.wa.gov/research/reports/fullreports/733.1.pdf

WSDOT Functional Classification map application:

 http://www.wsdot.wa.gov/mapsdata/travel/hpms/functionalclass.htm

Other References

Complete Streets Planning and Design Guidelines, North Carolina Department of Transportation,
July 2012.  http://www.pedbikeinfo.org/pdf/PlanDesign_SamplePlans_CS_NCDOT2012.pdf

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Context Determination Chapter 1102

Designing Walkable Thoroughfares: A Context Sensitive Approach, Institute of Transportation

Engineers, Washington D.C., 2010
 http://ecommerce.ite.org/IMIS/ItemDetail?iProductCode=RP-036A-E

Evaluating Transportation Land Use Impacts, Victoria Transport Policy Institute, 2015
 http://www.vtpi.org/landuse.pdf

The Innovative DOT: A Handbook of Policy and Practice, Smart Growth America, Washington
D.C., 2015
 http://www.smartgrowthamerica.org/the-innovative-dot

Land Use and Regional Planning: Achieving Integration Between Transport and Land Use,
European Commission, 2006  http://www.transport-
research.info/Upload/Documents/200608/20060831_102457_87241_Land_use.pdf

Livability in Transportation Guidebook: Planning Approaches that Promote Livability, FHWA,

2010  http://www.fhwa.dot.gov/livability/case_studies/guidebook/

Measuring Sprawl 2014, Smart Growth America, Washington D.C., 2014

 http://www.smartgrowthamerica.org/measuring-sprawl

NCHRP Report 855 – An Expanded Functional Classification System for Highways and Streets
http://www.trb.org/NCHRP/Blurbs/176004.aspx

Small Town and Rural Multimodal Networks (FHWA-HEP-17-024), December 2016.

 https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/small_towns/

Smart Transportation Guidebook, New Jersey Department of Transportation and Pennsylvania

Department of Transportation, 2008.
 http://www.state.nj.us/transportation/community/mobility/pdf/smarttransportationguidebo
ok2008.pdf

Urban Street Design Guide, National Association of City Transportation Officials, New York, NY,
2013  http://nacto.org/

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Chapter 1103 Design Control Selection
1103.01 General Overview
1103.02 Control: Design Year
1103.03 Control: Modal Priority
1103.04 Control: Access Control
1103.05 Control: Design Speed
1103.06 Control: Terrain Classification
1103.07 Documentation
1103.08 References

1103.01 General Overview

Design controls are specific factors that directly influence the selection of most design elements
and their dimensions. Design controls establish fundamental boundaries for design alternatives.
Selection of design controls is documented on the Basis of Design. This chapter provides
guidance on the selection of design controls for state routes.

The five WSDOT design controls include:

 Design Year
 Modal Priority
 Access Control
 Design Speed
 Terrain Classification

Exhibit 1103-1 WSDOT Design Controls

Reciprocal connections between

design controls and land use and
transportation contexts

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Design Control Selection Chapter 1103

1103.02 Control: Design Year

Design year is the forecast year used for design. The year of opening is when the construction
will be complete and the project location is fully operational. Design year selection is dependent
on a decision to design for the year of opening, or for a future year based on forecast or planned
conditions. Design year has historically been associated with a 20-year vehicle traffic forecast
used in development of large mobility and capacity expansion projects. This is the origin of the
term horizon year. Horizon year is typically considered to be 20 years from the year
construction is scheduled to begin.

WSDOT policy on design year is intentionally flexible. The design year can be any interim year
selected between the project year of opening year and the horizon year. Many lower-cost
projects result in immediate performance improvements when construction is completed.
Safety projects are an example of this where the basis of design may show design year as the
year of opening.

Some projects may require horizon year analysis of an alternative regardless of the selected
design year. A project may be required to evaluate alternatives based on the horizon year
(20 years from the scheduled beginning of construction) if the project:
 Involves a federal nexus (federal funds involved, involves federal lands, or requires
federal approvals or permits)
 Is a Project of Divisional Interest (See Chapter 300)
 Is a new/reconstruction project as defined in Chapter 300

Contact the region ASDE if there are questions.

1103.03 Control: Modal Priority

The concepts and method described in this section are adapted from National Cooperative
Highway Research Program Report 855: “An Expanded Functional Classification System for
Highways and Streets” (see http://www.trb.org/NCHRP/Blurbs/176004.aspx)

1103.03(1) Design Users

“Design users” refers to the modes that are legally permitted to use a facility. The intent in
identifying design users is to highlight all user needs, recognize modal interactions, and develop
an integrated system for all users. Identifying the design users is the first step in determining
which modes to accommodate and prioritize. On the Basis of Design, list design users with
sufficient descriptive detail. Include consideration for all ages and abilities.

Division III of the document Understanding Flexibility in Transportation Design – Washington is a

key resource for understanding the needs and characteristics of various design users.

1103.03(2) Modal Accommodation

Modal accommodation refers to the level to which a travel mode will be addressed in the
design. It is expressed on a scale of low, medium, and high, where a higher accommodation level
is associated with the use of design features or criteria that tend to improve the performance of
that mode compared to a lower level. Once established, the modal accommodation level is used
to inform the decision on modal priority (See 1103.03(3)). Determine the modal accommodation

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level for both the current year (prior to opening) and the design year. These are referred to as
existing and future conditions in the guidance that follows. Note that in many cases, the
planning documentation, data, or information in the project vicinity may not be available for the
project’s design year. In those cases, identify the forecast or horizon year used by the local
agency or planning organization in its work and planning products, and document the use of
that year as the future year for purposes of determining the modal accommodation level.
1. An initial modal accommodation determination, for both the current and design years, are
made using Exhibit 1103-2. The initial determination uses the roadway type and land use
contexts that were determined earlier and documented in Section 2 of the Basis of Design
(See Chapter 1102).
2. A final determination for both the current and design years is made using additional
information and evidence to validate or modify the initial determination.
Make the final modal accommodation determination for each mode in consultation with the
project advisory team and/or subject matter expert(s), as they may recommend modifications
to the initial determinations (see 1100.04 for more information about working with the project
advisory team). Exhibit 1103-3 provides examples of land-use and transportation characteristics
that a project advisory team or subject matter expert(s) may consider in adjusting
accommodation up or down for any particular travel mode. These characteristics can represent
either the current suitability of a facility to accommodate a mode, or its future strategic role
with respect to accommodating that mode. Note that the Context and Modal Accommodation
Report provides a template for making and documenting decisions about modal
accommodation.

Exhibit 1103-2 – Initial Modal Accommodation Level

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Design Control Selection Chapter 1103

Additional guidance on the use of the following criteria in determining final modal
accommodation level is provided on the Design Support site:
http://www.wsdot.wa.gov/Design/Support.htm

Exhibit 1103-3 Example Characteristics Related to Modal Accommodation

Land Use Characteristic Increased Modal Accommodation Level

High proximity to activity centers Pedestrian, Transit, Bicycle
Industrial and commercial land uses in surrounding area Auto, Freight
High densities of both residential and employment Bicycle, Pedestrian, Transit
Minimal building setbacks adjacent to roadway Bicycle, Pedestrian
Human scale architecture present Bicycle, Pedestrian, Transit
Transportation Characteristic Increased Modal Accommodation Level
Well-established grid network Bicycle, Pedestrian, Transit, Auto
T-2 freight route Auto, Freight
Streetside elements Bicycle, Pedestrian, Transit
Frequent signalized intersections along route Auto, Transit, Pedestrian

1103.03(2)(a) Vehicle modal accommodation level

Consider the vehicle modal accommodation level when making design decisions that address or
affect needs associated with vehicle travel. Start with the initial modal accommodation level for
motor vehicles per Exhibit 1103-2, and adjust it to establish the final level based on documented
project specific conditions related to the quality of travel experience, and identified
performance targets, that can be influenced by the project design, such as vehicle Level of
Service, travel time, access classification, and other factors determined by subject matter
experts or the project advisory team.
1103.03(2)(b) Bicycle modal accommodation level

Consider the bicycle modal accommodation level when making design decisions that address or
affect needs associated with bicycle travel. Start with the initial modal accommodation level for
bicycles per Exhibit 1103-2, and adjust it to establish the final level based on documented
project specific conditions related to the quality of travel experience, and identified
performance targets, that can be influenced by the project design, such as bicycle route type,
efficiency of travel, range, bicyclist safety, route spacing, bicycle volumes, and other factors
determined by subject matter experts or the project advisory team.

1103.03(2)(c) Pedestrian modal accommodation level

Consider the pedestrian modal accommodation level when making design decisions that
address or affect needs associated with pedestrian travel. Start with the initial modal
accommodation level for pedestrians per Exhibit 1103-2, and adjust it to establish the final level
based on documented project specific conditions related to the quality of travel experience, and

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Chapter 1103 Design Control Selection

identified performance targets, that can be influenced by the project design, such as pedestrian
route type, efficiency of travel, range, pedestrian safety, block length, and other factors
determined by subject matter experts or the project advisory team.

1103.03(3) Modal Priority

Accommodate means that the roadway will be designed so that the chosen modes can use it,
while accommodation level refers to the extent to which that accommodation may be required.
Priority refers to the decision to optimize the design based on the performance of one or more
travel modes. Modal priority is used as input to choosing the appropriate geometric cross
section (see Chapter 1230).

Modal priority addresses all modes expected to use the facility. Determine modal priority using
the accommodation level results, as well as other relevant information about freight, transit,
and any other modes considered and documented in the Context and Modal Accommodation
Report and Basis of Design. Engage the project advisory team as provided in Section 1100.04.

If the modal priority is inconsistent with assumptions made about the project during a planning
or scoping phase, work with program management staff to consider the need for any changes to
project scoping documentation, including scope, schedule, and budget.

Document the modal priority on the Basis of Design for both the current and future conditions.

1103.03(4) Intersection Design Vehicle

WSDOT policy provides flexibility when choosing the intersection design vehicle. The purpose
for this policy is to balance user needs and avoid the unnecessary expense of oversizing
intersections. Considerations include frequency of the design vehicle and effects on other design
users, specifically pedestrian crossing distance and times, and bicycle turning and through
movements. Consider providing more protected intersection treatments for pedestrians and
bicyclists to mitigate turning conflicts.

An intersection design vehicle is a specific selection made at each intersection leg. Select a
design vehicle that allows the largest vehicles commonly encountered to adequately complete a
required turning maneuver. The objective is not necessarily to size the specific intersection curb
radius (unless there is a baseline need associated with the larger vehicles), but rather to account
for a reasonable path to accommodate the large vehicle turning maneuver without conflicts (see
Chapter 1310). Use turn simulation software (such as AutoTURN®) to analyze turning
movements.

Example: An intersection with a pedestrian modal priority experiences infrequent turning

movements by a WB-67. A smaller curb radius would benefit pedestrians due to shorter
crossing times and reduced exposure to vehicles. Using turn simulation software, a
practicable path for the WB-67 can be identified, even though path intrusion into the
second same direction lane or painted median may be necessary. The infrequent use by a
WB-67, along with the pedestrian modal priority, validate the decision for selecting a
smaller design vehicle for the intersection while accommodating the WB-67 vehicle.

Conversely, if the crossroad was identified as being within a Freight Economic Corridor, with
frequent turning movements from larger vehicles, it would be appropriate to size the
intersection to prevent the second lane incursion.

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Consider origins and destinations of large vehicles to understand their needs at specific
intersection locations. Also, consider alternatives that may help lower turning speeds and
minimize pedestrian exposure. Work with stakeholders, businesses, and service providers to
understand their needs (like transit, school bus and emergency vehicle movements) and define
the frequency of use at specific intersections. Municipalities may have established truck routes
or restrictions that govern local freight patterns.

1103.04 Control: Access Control

Access is a critical component informed by an understanding of the land use and transportation
contexts. The type of access control selected (see Chapter 520) affects accessibility and impacts
the types of activities and functions that can occur on a segment. It is important for mobility and
economic vitality projects to consider whether the current access classification and/or planned
access classification conforms to the context selected for design (see Chapter 1102).

During development of the state highway system, access management functioned to preserve
the safety and efficiency of regional highways. However, the level of access management can
also significantly affect accessibility to land uses, modal mobility needs and the economic vitality
of a place.

Unless access control has already been acquired by the purchase of access rights, it is necessary
to select the appropriate type of limited access control or managed access control during
planning and design. Appropriate access control should be considered so as not to hinder
bicycle and pedestrian accessibility, mobility, and safety.

A choice to change the current or planned access control is a major decision and is to be
consistent with the context, desired performance targets, and modal priorities for a location.

Example: The area around a managed access Class 2 route has incurred significant
development, increasing the number of local trips on a segment of the route. Over time,
additional intersections and access connection permits have been granted. In this situation,
it may be appropriate to consider selecting managed access Class 4 or 5 because of the
changes in functions and activities along the segment over time.

Conversely, a route may have a need to improve motor vehicle travel time performance,
and managed access Class 1 may be appropriate.

If an alteration to current or planned access is determined necessary, consult the Headquarters

Access and Hearings Manager for preliminary approval for the selection, and document on the
Basis of Design (see Chapter 1100). For additional information on access control and access
management, see Chapters 520, 530, and 540.

1103.05 Control: Design Speed

WSDOT uses a target speed approach for determining design speed. The objective of the target
speed approach is to establish the design speed at the desired operating speed. The target
speed selection is derived from other design controls, as well as transportation and land use
context characteristics.

Exhibit 1103-4 shows possible (planning level) target speeds for the various roadway types and
land use contexts discussed in Chapter 1102. The target speeds shown in the exhibit are

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Chapter 1103 Design Control Selection

suggestions only, and the target speed for the specific location may vary from those shown in
the exhibit.
Exhibit 1103-4 Target Speed Based on Land Use Context and Roadway Type

Land-Use Context
Rural Suburban Urban Urban Core

Freeways High High High High

Roadway Type

Intermediate / Low /
Principal Arterial High Low
High Intermediate
Low/ Low /
Minor Arterial High Low
Intermediate Intermediate
Low/ Low/
Collector Low Low
Intermediate Intermediate
Low/
Local Low Low Low
Intermediate

Engage the public, local agency staff and officials, and transit agencies prior to selecting the
target speed. Once the target speed has been selected, it becomes the design speed for the
project. The goal of the target speed approach is that the speed ultimately posted on the
completed project is the same as the design, and ultimately, the operating speed. In order to
achieve this outcome, consider:
 The impact of existing or proposed contextual characteristics
 Modal priorities
 Access control selection
 Performance need(s)
 Contributing factors analyses that have been developed for the project

Lowering target speed: When selecting a target speed in excess of the existing posted speed, or
where excessive operating speeds were identified from contributing factors analysis of the
baseline performance need, consider the use of roadway treatments that will help achieve the
selected target speed (see 1103.05(2)) during alternatives formulation.

Speed management treatments are used to achieve lower vehicle speeds. When speed
management treatments are proposed to accomplish a desired target speed operation
concurrence of the Region Traffic Engineer is required. When a design speed is proposed for a
project that is lower than the existing posted speed, the approval of the State Traffic Engineer is
also required. See 1103.05(2) below for more on speed management. Careful consideration of
other modal needs should be evaluated before raising target speeds.

Raising target speed: When selecting a target speed in excess of the existing posted speed,
measures such as greater restriction of access control and segregation of modes may be
necessary to reduce conflicts in activities and modal uses. Wider cross sectional elements like
lanes and shoulders are used with higher speed facilities.

Setting the posted speed: Use caution when basing a target speed on one or more contextual
characteristics that are proposed to take place after project opening, as the goal of ending up
with a posted speed equal to the design speed at opening may be jeopardized.

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The Region Traffic Engineer is responsible for setting the posted speed on the highway once the
project is completed. Target speed is only one of the considerations used when establishing
posted speed. Engage and include the Region Traffic Engineer and Traffic Office staff in key
decision-making that will affect the target, design, and operating speed selection. . Incorporate
consideration of traffic calming measures as needed.

1103.05(1) Low, Intermediate, and High Speeds

To provide a general basis of reference between target speed and geometric design, WSDOT
policy provides three classifications of target speed as follows:
1. Low Speed is 35 mph and below. A low target speed is ideal for roadways with pedestrian
and bicycle modal priorities. Locations that include frequent transit stops, intermodal
connections, moderate to high intersection density, or moderate to high access densities
may also benefit from lower speed environments. Low speed facilities in urban areas
typically use narrower cross section elements.
2. Intermediate Speeds are 40 mph and 45 mph. An intermediate target speed is ideal for
speed transitions between high and low target speed environments. Locations with low
access densities and few at-grade intersections are also examples of where intermediate
speed may be appropriate. In these locations consider a higher degree of separation
between motor vehicles and bicycles and pedestrians.
3. High Speed is 50 mph and above. A high target speed is ideal for motor vehicle oriented
roadways such as freeways and highways, often serving regional or longer-distance local
trips. Rural connector roadways with infrequent farm or residential accesses are also
consistent with the use of high target speeds. In high target speed locations consider the
highest degree of separation between motor vehicles and bicycles and pedestrians.
Highways with high speeds are associated with wider cross section elements.

1103.05(2) Speed Management

Speed management is necessary within many highways to achieve an optimal multimodal
facility that will support the land use and transportation contexts. Speed management may also
be necessary to maintain consistent or desired speeds between adjacent roadway segments.
Identify speed transition segment(s) as necessary to achieve desired speeds. Identify potential
speed transition segments when scoping the project.

1103.05(2)(a) Speed Transition Segments

Include a speed transition segment where there is a need to obtain a target speed lower than
the existing operating speed. A speed transition segment is not needed where existing operating
speeds are within 5 mph of the target speed for a given location. The transition segment may
not always directly precede the speed zone segment as shown in Exhibit 1103-5.

Example: A residential segment could benefit from introducing a speed transition segment
farther upstream to increase the likelihood that approaching vehicles operate at the desired
speed, for both segments.

The speed transition segment may incorporate a variety of treatments that alert motorists to a
changing roadway environment. These treatments are intended to narrow driver focus and/or
affect driver decision-making on that segment. Consider the transition segment location and
length when providing multiple treatments in a short distance.

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Chapter 1103 Design Control Selection

Exhibit 1103-5 Speed Transition Segment Example

1103.05(2)(b) Speed Reduction Traffic Calming Treatments

Traffic calming treatments can serve a variety of purposes, from deterring higher volumes of
motorized traffic to providing speed management. This section presents traffic calming
treatment options to increase the reliability of reducing vehicular speed. Speed reduction traffic
calming treatments applied independently or in combination may be beneficial depending on
the type and use of the treatments. Many speed management treatments have demonstrated
varied effectiveness for single applications. Multiple treatments in series and parallel that build
upon the context characteristics are more effective. Contact the Headquarters Design and
Traffic offices for any project implementing a speed transition segment, for assistance on
selection and monitoring of treatments.

Speed management techniques vary and have different results depending on the speed and
types of users at a given location. The following subsections present different options for speed-
reducing traffic calming treatments.
1103.05(2)(b)(1) Geometric Treatments

Geometric treatments can include overall changes of the horizontal or vertical geometry to
introduce features that will support maintaining the targeted speed. Exhibit 1103-6 shows
geometric traffic calming treatments and potential considerations when selecting these types of
treatments.
1103.05(2)(b)(2) Roadside and Pavement Treatments

There are a number of treatments that create an environment that influences human factors
and perception. Many successful roadside treatments use landscaping in an attempt to achieve
the desired behavioral effect. It is important to coordinate with project partners to evaluate
landscaping features and provide for traveled way operations and sight lines. The introduction
of roadside features like trees, parking, and/or bicycle lanes to alert travelers to a change in
conditions may be appropriate. Applying features like vegetated medians or trees is appropriate
at some locations and contexts. In landscaping discussions, include Traffic Engineers,

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Design Control Selection Chapter 1103

Maintenance, Urban Forestry, Landscape Architects, and Human Factors and Safety Experts. If
the landscaping proposed is in a managed access segment with local jurisdiction responsibility
for the roadside, coordinate to understand the jurisdictions’ capabilities to sustain the
landscaping and that it meets their clear zone goals.

Pavement-related treatments can also produce undesirable impacts on other users. For
pavement-related treatments, include Materials Engineers, Maintenance, Traffic, and ADA
Compliance Experts to review what sustainable and effective treatments can be employed.

Exhibit 1103-7 lists roadside and pavement-related traffic calming treatments and
considerations to evaluate.

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Exhibit 1103-6 Geometric Traffic Calming Treatments and Considerations

Treatment Considerations
Narrowing the lane width can be achieved by restriping lane lines. A decision to
taper in or out may depend on other treatments planned, such as introducing a
Taper for Narrow Lanes median or chicanes. Base taper rates on the target speed entering the context or
speed transition segment, as appropriate. It is recommended that this be the first
treatment employed.
This treatment may be achieved with curbed features, like planter strips or striping
combined with additional fixed delineators. These treatment types are more
appropriate when reducing speeds from an initial intermediate speed or less. When
Chicanes/Lane Shifts
introducing this treatment with initial high speeds, the treatment should utilize
paint striping, in addition to using other treatments preceding the chicane/lane
shift, rather than constructing hardscape features.
Applies on intermediate to low target speed situations unless completed with
striping or other pavement markings. This treatment uses striping, roadside
features, or curb extensions to temporarily narrow the vehicle lane. It is likely more
Pinch Points appropriate for maintaining a desired target speed within a segment than as part of
a speed transition segment. Pinch points are not appropriate for high-speed
segments. Use of pinch-point treatments on intermediate speed segments requires
concurrence from the Region Traffic Engineer.
On state highways, this treatment will likely have limited application, but should
not be excluded from consideration. Impacts to freight, transit, and emergency
Speed
service vehicles need to be evaluated prior to selecting these vertical types of
Cushion/Humps/Tables
treatments. These treatments may only be used when maintaining a 25 mph target
speed within a segment.
Raised intersections, similar to other vertical treatments, will have limited
application on state highways. This treatment typically has higher costs to construct
due to the pavement needs. This treatment may be a good option when a
roundabout cannot be accommodated at a narrow intersection. It can also be
Raised Intersections
considered where there is a need to improve visibility of the intersection and modal
conflicts, especially at problematic stop control intersections planned to remain in
place. This treatment may only be used when maintaining a 25 mph target speed
within a segment.
Roundabouts can be a unique feature, providing reduced fatal and serious injury
crash potential, traffic calming, and gateway functions (See Chapter 1320 and the
Roadside Policy Manual for details on roundabout design). Roundabouts are
effective from a collision reduction and operational perspective, and they provide
Roundabouts reduced driver workload, lower speeds, and limited conflict points. They can assist
with access management or when turning movements are limited or restricted on a
segment. To determine if a roundabout is appropriate at a specific location, follow
the Intersection Control Evaluation process described in Chapter 1300.

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Exhibit 1103-7 Roadside, Streetside, and Pavement-Oriented Traffic Calming Treatments

Treatment Considerations
Landscaping can be used in conjunction with other treatments to reinforce the
surrounding context and the driver’s perception of the context. It can also provide
Landscaping
width for modal separation. Annual maintenance impacts need to be considered,
weighed, and documented prior to selecting types of vegetation to be included.
Introduce a raised vegetated median following other treatments that prepare the
Raised Vegetated
driver for this feature. Appropriate for low to intermediate target speed locations and
Medians
transition segments.
These in-lane rumble strips are intended to alert drivers to a condition change. They
Transverse Rumble are likely placed in conjunction with and prior to traffic signing revisions or in advance
Strips of other speed-reducing traffic calming treatments. Appropriate for high,
intermediate, or low target speed locations and transition segments.
This treatment is intended to influence a driver’s perception. The treatment consists
of 8-inch transverse paint strips within the vehicular lane extending from lane and
edge markings (or curb). The striping intervals sequentially decrease, providing the
Optical Speed
perception of increasing speed, an indication to drivers to slow their operating speed.
Markings
Optical Speed Markings are ideal for speed transition segments, and are
recommended to be applied in conjunction with lane narrowing for high or
intermediate target speed locations.
This treatment consists of actively alerting motorists about their operating speed.
Dynamic Warning There are many different systems that accomplish this, including portable radar
Systems trailers and post-mounted systems. These can be either permanent or temporary
installations. Appropriate for all speeds.
The intent of a gateway feature is to alert travelers to a context change. A gateway
feature is typically found on the edge of cities or towns, but can be used to highlight
specific segments within cities or towns. The gateway can be anything from a
banner/structure spanning the facility, to artistic work, landscaping, and/or a
roundabout at the first intersection approaching a defined environment context. The
Gateways gateway feature should be developed by the community. It may be of interest to
design a gateway feature fitting the cultural and historic character of the location.
Consideration for potential fixed object collisions is an important aspect of gateway
design. Gateway features that span or are placed within state right of way will need
specific approvals, as identified in Chapter 950. Appropriate for low to intermediate
target speed locations and transition segments.

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1103.06 Control: Terrain Classification

Terrain may limit operational and safety performance for particular modes. While terrain
impacts may be addressed at specific locations, it is not cost beneficial to modify terrain
continually throughout a corridor. The type of terrain, context, and speed influence the
potential operating conditions of the highway, and should be a consideration when selecting
mobility performance targets (See Chapter 1101). For more information on grades, see
Chapter 1220.

To provide a general reference between terrain and geometric design, three classifications of
terrain have been established:
1. Level: Level to moderately rolling, this terrain offers few or no obstacles to the construction
of a highway having continuously unrestricted horizontal and vertical alignment.
2. Rolling: Hills and foothills, with slopes that rise and fall gently; however, occasional steep
slopes might offer some restriction to horizontal and vertical alignment.
3. Mountainous: Rugged foothills; high, steep drainage divides; and mountain ranges.

Designate terrain as it pertains to the general character along the alignment of a corridor.
Roadways in valleys or passes in mountainous areas might have the characteristics of roads
traversing level or rolling terrain and are usually classified as level or rolling, rather than
mountainous. See the Highway Log for terrain classification.

1103.07 Documentation
Document selections for design controls in Section 3 of the Basis of Design.

1103.08 References

1103.08(1) Federal/State Directives, Laws, and Codes

Secretary’s Executive Order 1090 – Moving Washington Forward: Practical Solutions

Secretary’s Executive Order 1096 – WSDOT 2015-17: Agency Emphasis and Expectations

1103.08(2) Supporting Information

Design Support website to download the Basis of Design and Context and Modal
Accommodation Report:  http://www.wsdot.wa.gov/Design/Support.htm

Designing Walkable Thoroughfares: A Context Sensitive Approach, Institute of Transportation

Engineers, Washington D.C., 2010  www.ite.org

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, Washington, D.C.,
Current Edition  www.transportation.org/Pages/Default.aspx

Urban Street Design Guide, National Association of City Transportation Officials, New York, NY,
2013  www.nacto.org

Understanding Flexibility in Transportation Design – Washington, WA-RD 638.1, Washington

State Department of Transportation, 2005
 www.wsdot.wa.gov/research/reports/fullreports/638.1.pdf

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Design Control Selection Chapter 1103

NCHRP Report 613 – Guidelines for Selection of Speed Reduction Treatments at High Speed
Intersections, Transportation Research Board, Washington D.C., 2008
 http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_613.pdf

NCHRP Report 737 – Design Guidance for High-Speed to Low Speed Transition Zones for Rural
Highways, Transportation Research Board, Washington D.C., 2012
 http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_737.pdf

NCHRP Report 600 – Human Factors Guidelines for Road Systems, 2nd Edition, Transportation
Research Board, Washington D.C., 2012
 http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_600Second.pdf

NCHRP Report 855 – An Expanded Functional Classification System for Highways and Streets
 http://www.trb.org/NCHRP/Blurbs/176004.aspx

NCHRP Synthesis 443 – Practical Highway Design Solutions, Transportation Research Board,
Washington D.C., 2012  http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_syn_443.pdf

Measuring Sprawl 2014, Smart Growth America, Washington D.C., 2014

 http://www.smartgrowthamerica.org/measuring-sprawl

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Chapter 1104 Alternatives Analysis
1104.01 General
1104.02 Alternative Solution Formulation
1104.03 Alternative Solution Evaluation
1104.04 Documentation
1104.05 References

1104.01 General
Washington State Department of Transportation practical design policy requires formulating
and evaluating alternatives while considering acceptable performance trade-offs to meet the
need(s) of a project at the lowest level of investment. This chapter discusses how:
 Information determined from planning phases and Chapters 1101, 1102, and 1103 is
utilized in alternative solution formation
 To evaluate the alternative solutions developed

This chapter presents methods for developing alternatives. For projects requiring an
Environmental Assessment (EA) or an Environmental Impact Statement (EIS), a final proposed
alternative may only be determined through the National Environmental Policy Act (NEPA)
process and/or the State Environmental Policy Act (SEPA) process (see Chapter 400 of the
Environmental Manual for more information). If an EA or EIS has not been initiated under
NEPA/SEPA, follow the procedures in this chapter. To help advance the project, consider and
use appropriate NEPA/SEPA terminology. Perform public and agency outreach and document all
information regarding alternatives development for use later in the NEPA/SEPA process,
according to 23 CFR 168(d). Terminology used in this chapter assumes that NEPA/SEPA have not
been initiated. In the event that the NEPA/SEPA process has been initiated and an EA or EIS will
be required, coordinate with the region Environmental Office staff to make sure that this
alternative formulation and evaluation is performed in accordance with NEPA/SEPA guidance.

1104.02 Alternative Solution Formulation

An important function of alternative solution formulation is to identify alternatives that address
the baseline need while balancing the performance trade-offs identified in the process. This can
include analysis of multimodal trade-offs and the formulation of multimodal/intermodal
solutions. Need identification and contributing factor analysis (CFA) are critical to alternative
solution formulation (see Chapter 1101 and guidance document Contributing Factors Analysis
for more information). Conduct alternative solutions formulation according to the following
principles:
 Formulate alternatives compatible with context and design controls
 Form solutions around contributing factors or the underlying root reason(s) identified
from CFA. Address the underlying root reason(s) determined from CFA in at least one
alternative.
 Evaluate the relative benefit between each alternative against the baseline and
contextual performance metrics to determine the optimally performing solution for the
least cost. (See 1104.03(3) for information on calculating the benefit/cost of
alternatives.)

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Alternatives Analysis Chapter 1104

Planning phase corridor sketches or studies may identify WSDOT’s strategy for the corridor (see
the guidance document section titled Alternative Strategies and Solutions for more information
regarding different strategies that may be considered). If this has occurred, develop at least one
alternative based on that identified strategy and bring forward into the alternative evaluation
process (see 1104.03).

In some cases, planning studies may have developed specific alternatives. Carry planning phase
alternatives into the alternative evaluation process, unless planning phase alternatives are
obsolete. In some cases, alternatives may present opportunities for phased implementation.

1104.03 Alternative Solution Evaluation

Alternative solution evaluation involves understanding the performance benefits obtained from
alternative solutions in relation to the selected design year and cost. It is the intent of the
alternative solution evaluation process to:
 Compare solutions that resolve the baseline need(s) in consideration with the benefits
or impacts associated with the contextual needs.
 Analyze the relative value of each alternative, including associated performance
trade-offs.
 Mitigate unacceptable performance trade-offs with proven countermeasures.
 Refine targets if mitigation measures applied yield unacceptable performance
trade-offs.

1104.03(1) Alternatives Comparison

WSDOT’s alternatives comparison process is intended to align with performance-based decision-
making. The process is complementary to a practical design approach. The process centers
around achieving the basic performance need, while understanding and when necessary
mitigating for the potential effects to other performance areas.

Use the Alternative Comparison Table (ACT) to assist in evaluating alternatives and identified
baseline and contextual performance. The intent of comparing alternatives is to:
 Obtain an alternative solution for the least cost while understanding associated
performance trade-offs.
 Compare alternatives against their ability to accomplish the baseline need.
 Evaluate alternatives against their relative effects on contextual needs.
 Provide the opportunity to incorporate mitigation or countermeasures.
 Document alternative formulation and evaluation outcomes that are consistent with
the environmental process and expectations.

Note that if there are a large number of contextual needs under consideration, it may be
beneficial to prioritize or use a weighted evaluation of the contextual needs in order to expedite
the alternative evaluation.

As discussed in 1104.02, at least one alternative based on the outcome of Contributing Factors
Analysis should be compared against other alternatives.

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Chapter 1104 Alternatives Analysis

The Alternative Comparison Table template and examples can be found at:
 www.wsdot.wa.gov/Design/Support.htm

1104.03(2) Performance Trade-off Decisions

In performance trade-off decisions, the intent is to give priority to the project’s baseline needs.
However, there will be situations where evaluations reveal that trade-offs are too significant,
and there is an inability to adequately resolve them with low-cost countermeasures, phased
solutions, or general acceptance of the performance trade-off. In these situations, it is
appropriate to consider alternatives that still optimize the baseline performance metric, but do
not necessarily obtain initial performance targets. Document refined performance targets on
the Basis of Design.

1104.03(3) Benefit/Cost Analysis

Inherent with understanding the performance trade-offs being considered, is the overall
benefit/cost for the alternatives proposed. In some cases, decisions will be based on life cycle
cost for maintenance items, as discussed in Chapter 301. In other cases, perceived benefits are a
challenge to quantify and will need analysis such as that discussed in NCHRP Report 642:
Quantifying the Benefits of Context Sensitive Solutions:
 www.trb.org/Publications/Blurbs/162282.aspx

1104.04 Documentation
The Alternative Comparison Table (ACT) is used to assist in evaluating alternatives. Summarize
the alternatives evaluated with the ACT in Section 4 of the Basis of Design (BOD). Alternative
formulation and evaluation will also be documented through the NEPA process. Environmental
staff will help account for consistency with the environmental process, expectations and
requirements throughout any alternative formulation and evaluation that occurs within project
development.

1104.05 References

1104.05(1) Federal/State Directives, Laws, and Codes

42 United States Code (USC) 4321, National Environmental Policy Act of 1969 (NEPA)

Chapter 43.21C Revised Code of Washington (RCW), State Environmental Policy Act (SEPA)

Chapter 468-12 Washington Administrative Code (WAC), WSDOT SEPA Rules

Secretary’s Executive Order 1090 – Moving Washington Forward: Practical Solutions

Secretary’s Executive Order 1096 – WSDOT 2015-17: Agency Emphasis and Expectations

Secretary’s Executive Order 1028 – Context Sensitive Solutions

Secretary’s Executive Order 1018 – Environmental Policy Statement

1104.05(2) Guidance and Resources

Environmental Manual, M 31-11, WSDOT

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Alternatives Analysis Chapter 1104

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

Understanding Flexibility in Transportation Design – Washington, WA-RD 638.1, Washington

State Department of Transportation, 2005
 www.wsdot.wa.gov/research/reports/fullreports/638.1.pdf

1104.05(3) Supporting Information

Designing Walkable Thoroughfares: A Context Sensitive Approach, Institute of Transportation
Engineers, Washington D.C., 2010.
 www.ite.org

NCHRP Report 642 – Guidelines for Quantifying the Benefits of Context Sensitive Solutions,
Transportation Research Board, Washington D.C., 2014
 http://www.trb.org/Publications/Blurbs/162282.aspx

NCHRP Synthesis 443 – Practical Highway Design Solutions, Transportation Research Board,
Washington D.C., 2013
 http://www.trb.org/Main/Blurbs/168619.aspx

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Chapter 1105 Design Element Selection
1105.01 General
1105.02 Selecting Design Elements
1105.03 Related Elements
1105.04 Documentation
1105.05 References

1105.01 General
Design elements are specific components associated with roadway design, such as lane widths,
shoulder widths, alignments, clear zone, etc. Design controls (see Chapter 1103) are carefully
chosen and used to determine the dimensions of design elements. The relative effect that a
given design element will have on performance will depend on the selected design controls and
context identification. For more information, see: Guidance Documents - Information on
WSDOT's Practical Design Procedures, Research Summary of Different Design Elements on
Performance, which is the last section.

1105.02 Selecting Design Elements

Design elements that are included in a project are documented in the Basis of Design. Include
the design elements that are changed by the project. (See Chapter 1100 for more information
about Basis of Design.)

An element is changed if one of the following applies:

 A new element is added
 An existing element is removed or relocated
 A dimension - such as a width - is modified

A design element that is not changed is not documented in the Basis of Design.

The next step after selecting design elements is to choose the appropriate dimension for each
element. (See Chapter 1106 for information on selecting design element dimensions.)

1105.02(1) Required Design Elements and Criteria

There are also additional legal and policy-based considerations that require a decision of
whether or not to include certain design elements in a project; this depends on the program or
sub-program. See Exhibit 1105-1 for additional information regarding whether or not to include
these design elements in a project.

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Design Element Selection Chapter 1105

Exhibit 1105-1 Required Design Elements

Design Elements
Roadside
Program or Signing &
Clear Safety Illumination Signal
Sub-Program ADA Delineation ITS [8]
Zone [1] Hardware [7] Hardware
[4]
[3]
Apply the
I-1 Mobility Apply the Apply the content in
Apply the Apply the Apply the
I-3 Economic content in content in Chapter 1020
content in content in content in
Initiative - Trunk Chapter Chapters for signing [5]
Chapter Chapter Chapter
System 1510 1600, 1610 and Chapter
1600 1040 1050
I-6 Sound Transit (1510.05) and 1620 1030 for
delineation
Apply the
content in Apply the
All Preservation
Chapter [2] content in [2] [6] [2] [2] [5]
(P-1, P-2, P-3)
1120 Chapter 1120
(1120.03(2))

Apply the
I-2 Safety
content in
I-4 Environmental
Chapter [2] [2] [2] [6] [2] [2] [5]
Retrofit
1510
I-3 All Other
(1510.05)

Notes:
[1] See Chapter 1600
[2] Only include when changed as described in 1105.02.
[3] Includes all roadside safety design elements in Chapters 1600, 1610, and 1620.
[4] See Chapter 1020 for signing and Chapter 1030 for delineation
[5] Consult the Assistant State Design Engineer (ASDE), HQ Traffic Office, and Capital Program
Development and Management Office (CPDM) to determine policy requirements.
[6] Consult the ASDE for policy requirements if the roadway channelization is changed.
[7] See Chapter 1040
[8] See Chapter 1050

Page 1105-2 WSDOT Design Manual M 22-01.16

February 2019
Chapter 1105 Design Element Selection

1105.03 Related Elements

Design elements can be interrelated. Even if a specific design element has not changed in
accordance with the definition in 1105.02, consider whether or not the preferred alternative has
changed the conditions in a way that may affect the performance of an unchanged element,
considering all modes.

Example: A project team proposes to provide a left-turn lane along a portion of their project
in order to address a baseline need related to safety for turning traffic, by reducing the
width of each highway shoulder. By reducing the shoulder width, the traveled way will be
closer to the roadside than in the existing condition. The project team determines whether
the project would adversely affect safety performance due to roadside conditions such as
steep slopes or objects in the clear zone along with considering impacts to bike and
pedestrian use.

1105.04 Documentation
Document design elements that are changed in Section 5 of the Basis of Design (BOD) form
unless the exemptions listed in 1100.10(1) apply.

As a design alternative matures over time, it is likely that design elements may be added or
dropped through the iterative process inherent with design. It is important to update the Basis
of Design documentation with these changes at the various documentation and approval
milestones.

The Basis of Design is available to download here:

 www.wsdot.wa.gov/Design/Support.htm

1105.05 References
Guidance Documents - Information on WSDOT's Practical Design Procedures
 https://www.wsdot.wa.gov/publications/fulltext/design/ASDE/Practical_Design.pdf

WSDOT Design Manual M 22-01.16 Page 1105-3

February 2019
Design Element Selection Chapter 1105

Page 1105-4 WSDOT Design Manual M 22-01.16

February 2019
Chapter 1106 Design Element Dimensions
1106.01 General
1106.02 Choosing Dimensions
1106.03 The Mode/Function/Performance Approach
1106.04 Design Up Method
1106.05 Quantitative Analysis Methods and Tools
1106.06 Documenting Dimensions
1106.07 Design Analysis
1106.08 References

When choosing any dimension, read the guidance for the specific facility type (for example,
for ramps see Chapter 1360) and also read the guidance for the specific element (for example
for side slopes see Chapter 1239).

When a range of dimensions is given, consider modal needs, required function, and desired
performance (1106.03) and, where possible, use quantitative tools to help choose a
dimension within the range.

1106.01 General
Practical design resolves the project need with the least investment. Flexibility in the choice of
design element dimensions helps accomplish this.

For guidance related to geometric cross-section elements, first see Chapter 1230. For guidance
related to all other design elements, see the appropriate chapter.

1106.02 Choosing Dimensions

Depending on the facility type, Design Manual guidance may come in the form of a single
dimension or a range of dimensions to choose from. See Exhibit 1106-1.

For some roadways, the optimum solution is very dependent on the location (context) of the
roadway. In these cases, you will likely see a range of widths to choose from. For example, the
geometric cross section guidance chapters for highways (Chapter 1231) and freeways (Chapter
1232) show cross-sections that list ranges to choose from for lane and shoulder widths.

The mode/function/performance approach described in 1106.03 is the tool to be used to

choose the appropriate width from the range given.

WSDOT Design Manual M 22-01.14 Page 1106-1

July 2017
Design Element Dimensions Chapter 1106

Exhibit 1106-1 Dimensioning Guidance Variations

Example: Exhibit
1360-14b calls out
one specific
dimension for the
lane width of this
section of a parallel
off connection.

Example: Exhibit
1231-3 calls out a
range of dimensions
for the lane width.

When a single dimension is given: If the decision is to use the dimension shown, no further
evaluation is needed; just document the dimension choice on the Design Parameter Sheets.

If a particular roadway warrants use of a dimension that is different than the value given, the
mode/function/performance approach described in 1106.03 can be used to determine the
appropriate dimension. Results will need to be documented in a Design Analysis.

When a range of widths is given: Understand any width considerations specific to the design
element (for example, lane width considerations are described in Chapter 1231). Use the
mode/function/performance approach described in 1106.03 to choose the appropriate value
within the range. If the dimension chosen is within the range given in the Design Manual,
document the reasoning in the Design Parameter Sheets. If the value chosen is outside of the
given range, document the decision in a Design Analysis.

Some dimension choices can be complex, and involve trade-off evaluations, including
comparisons of alternatives, benefit/cost analysis, etc. In these instances, it may be appropriate
to record the dimension choice on the Design Parameter Sheets and reference any related
documents that support the dimension choice.

1106.03 The Mode/Function/Performance Approach

The mode/function/performance approach is the primary methodology to apply when a range
of dimensions is given. Utilizing this approach ensures that modal needs, the function of the
design element, and safety and mobility performance have all been considered. For example,
lanes and shoulders have to accommodate the modes that use the roadway, provide functions
that are appropriate for the specific roadway, and provide appropriate safety and mobility
performance.

Page 1106-2 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1106 Design Element Dimensions

Modes, function and performance overlap and are interrelated. These considerations are part of
a tradeoffs discussion. Cost is always a consideration in a tradeoffs discussion. Engineering
judgment and stakeholder involvement will be required.

Exhibit 1106-2 Mode/Function/Performance Approach

Modal accommodation: It is important to understand the modal needs for a roadway.

Accommodating a specific mode (or modes) may influence the dimension choice.

For example, it is important to understand the vehicle mix that will be using the lanes and to
understand the modes that will be using the shoulder. For lanes, a significant number of trucks
and oversized vehicles may affect the lane width choice, especially if the alignment is not
tangent. Read Chapter 1231 when choosing lane widths.

For shoulders, it is important to understand bicyclist and pedestrian use. The width
requirements that come with accommodating various modes are discussed in Chapter 1239.

Function(s): Function is closely related to modal accommodation. Providing a specific function

may drive the dimension choice.

For example, the shoulder width requirements that come with providing various functions bring
a wide range of associated widths (see Exhibit 1239-2, Shoulder Function & Modal
Accommodation Width Considerations).

Performance: When choosing a dimension from a range of possible choices, consider safety
performance and mobility performance. Meeting safety or mobility performance targets may
drive the dimension choice.

When evaluating performance, the use of quantitative engineering methods and tools is
encouraged whenever possible. See 1106.05 for more information on quantitative tools and
methodology for evaluating safety and mobility performance.

An important consideration of performance evaluation is whether or not the project has an

identified baseline (or contextual) safety need. If safety need has been identified, performance
metrics and targets may play a major role in choosing dimensions. See Chapter 1101.

WSDOT Design Manual M 22-01.14 Page 1106-3

July 2017
Design Element Dimensions Chapter 1106

For some projects, modal accommodation needs may drive lane and shoulder width decisions.
In other cases, the need to provide a specific function may drive width decisions. And, in some
cases, meeting established performance targets may drive width decisions. Regardless of
whether modal accommodation, function, or performance drives the dimension choice, the
effect of the decision on mobility and safety performance has to be considered.

Accommodating modal needs, providing specific functions, or achieving specific performance

targets may require widths that can bring significant investments. Consider the cost and
associated trade-offs, and document why it is worthy of the associated investment.

In addition to being the primary method to choose a dimension when a range of dimensions is
given, the mode/function/performance approach can also be used in support of a Design
Analysis.

1106.04 Design Up Method

When a range of dimensions is given, guidance may specifically require a “design up” approach.
For example, Chapter 1231 requires a design up approach for state highways other than
freeways.

Design up means considering the smallest dimension first. Increasing dimensions are then
considered until the smallest dimension is identified that accommodates modal needs, provides
the desired functions, and provides appropriate safety and mobility performance. Using the
mode/function/performance approach described in 1106.03 is an important part of design up.

1106.05 Quantitative Analysis Methods and Tools

Currently, two primary tools exist to quantitatively evaluate performance; the Highway Safety
Manual (HSM) for evaluating modal safety performance and the Highway Capacity Manual
(HCM) for evaluating traffic operational mobility performance.

1106.05(1) Highway Safety Manual and Safety Modeling

Safety is and always has been a primary performance category for WSDOT. Past design policy
relied on the assumption that the application of design criteria equated to a desired level of
safety performance for the expenditure. This assumption may not have always been true for all
locations given their operational and geometric characteristics. The strict application of criteria
to achieve safety performance is known as “nominal safety.” To achieve a more reliable safety
performance, scientific estimation of crashes using site conditions is necessary and is termed
“substantive safety.” A new understanding of safety performance, crash modification factors,
and roadway functions has led to a growing body of knowledge about the relationship between
roadway characteristics and safety performance.

The application of the Highway Safety Manual (HSM) and its companion tools provides an
understanding of how a particular design can perform with respect to safety. This enables
analysis of safety-specific performance metrics that may be more critical to address. The HSM
covers multiple transportation road types and can be a valuable tool to analyze various
geometric alternatives in any program type.

For guidance regarding whether or not to include a baseline safety need see Chapter 1101. For
more information on sustainable highway safety tools and analysis, see Chapter 321.

Page 1106-4 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1106 Design Element Dimensions

1106.05(2) Highway Capacity Manual and Traffic Modeling

The Highway Capacity Manual (HCM) provides quantitative methods for evaluating mobility
operational performance. However, some quantitative outputs from some HCM methods are
specific to free-flow speed operations or level of service, and may not be appropriate for use
given the baseline mobility performance metric selected for a specific location. Traffic modeling
software provides a more relevant method for understanding the mobility operational
performance; however, the reliability of the outputs varies given the traffic forecasting for
design years further in the future. Utilize traffic modeling to ascertain potential mobility
operational performance whenever feasible.

1106.06 Documenting Dimensions

While a primary function of the Basis of Design is to document the design elements selected to
be included in a project, another primary function of the Design Parameter Sheets is to
document the dimensions chosen for the various design elements included in a project.

Important Note: If the dimension for an existing design element does not change, no
documentation is required on the Design Parameter sheets. A Design Parameter Sheet entry left
blank means that the element was not selected to be included in the project. (See Chapter 1105
for design element selection guidance.) A Design Parameter Sheet template can be found here:
 http://www.wsdot.wa.gov/Design/Support.htm.

1106.07 Design Analysis

A Design Analysis is required when a dimension chosen does not meet the value, or fall within
the range of values, provided for that element in the Design Manual (see Chapter 300.) The
considerations described in 1106.03 may be useful when completing a Design Analysis.

1106.08 References
Highway Capacity Manual (HCM), latest edition, Transportation Research Board, National
Research Council

Highway Safety Manual (HSM), AASHTO

Washington State’s Target Zero Strategic Safety Plan

 http://www.targetzero.com/plan.htm

WSDOT Design Manual M 22-01.14 Page 1106-5

July 2017
Design Element Dimensions Chapter 1106

Page 1106-6 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1120 Preservation Projects
1120.01 General
1120.02 Structures Preservation (P2) and Other Facilities (P3)
1120.03 Roadway Preservation (P1)
1120.04 Documentation

1120.01 General
This chapter provides information specific to preservation project types.

This chapter identifies those elements and features to be evaluated and potentially
addressed during the course of a preservation project. The elements listed here may be in
addition to the project need identified in the Project Summary or Basis of Design (see
1120.03(8)). Preservation projects may also provide opportunities for project partnering and
retrofit options involving additional elements (for example see Section 1231.06).

Preservation projects are funded in three sub-program areas:

 Roadway Preservation (P1) projects preserve pavement structure, extend
pavement service life, and restore the roadway for reasonably safe operations of
the travel modes accommodated by the facility.
 Structures Preservation (P2) projects preserve the state’s bridge network through
cost-effective actions. There are numerous types of bridge preservation actions
including: deck rehabilitation, seismic retrofit, painting steel bridges, scour repair,
and others.
 Other Facilities (P3) projects preserve the function of guardrail and signing, major
drainage, major electrical, unstable slopes and other assets.

For required design elements in these programs see Exhibit 1105-1.

For more information on these programs see the Planning & Programming – Scoping
website:
 http://wwwi.wsdot.wa.gov/Planning/CPDMO/PlanProgScoping.htm

1120.02 Structures Preservation (P2) and Other Facilities (P3)

For Structures Preservation (P2) and Other Facilities (P3) projects see the scoping instructions
specific to the sub-program and type of work to determine the likely design elements to be
addressed by the project.

See Chapter 300 for documentation requirements. If the project changes a geometric design
element, replaces an existing bridge or installs a new bridge additional documentation may
be required; contact your ASDE to discuss appropriate documentation.

WSDOT Design Manual M 22-01.18 Page 1120-1

December 2019
Preservation Projects Chapter 1120

1120.03 Roadway Preservation (P1)

This section applies to features and design elements to be addressed on Roadway
Preservation (P1) projects. See Section 1120.04 for instructions on using the Basis of Design
to document design elements that are changed by the project.

1120.03(1) Adjust existing features

Adjust existing features such as monuments, catch basins, and access covers that are
affected by resurfacing.

Evaluate drainage grates and gutter pans, and adjust or replace as needed to address the
potential for bicycle crashes (see Drainage Grates and Manhole Covers in Chapter 1520).

For guidance on existing curb see Chapter 1239.

Replace rumble strips if they are removed through project actions, or if their average depth is
less than 3/8”, unless there is a documented justification for their removal (see Chapter
1600).

1120.03(2) ADA requirements

Address ADA requirements according to WSDOT policy (see Chapter 1510 and any active
project delivery memorandums or design memorandums).

1120.03(3) Cross slope lane

Rebuild the cross slope to a minimum 1.5% when the existing cross slope is flatter than 1.5%
and the steeper slope is needed to provide adequate highway runoff. See Chapter 1250 for
more information about cross slope.

1120.03(4) Cross slope shoulder

When rebuilding the lane cross slope, evaluate shoulder cross slope in accordance with
Chapter 1250.

1120.03(5) Vertical clearance

Paving projects, seismic retrofit, and other project work can change the vertical clearances of
structures. For preservation projects other than bridge replacement that have no widening
on or under the bridge, the minimum structure clearance is 14.5 feet. Existing structures with
a vertical clearance less than 14.5 feet require a Design Analysis.

If the vertical clearance of a structure will be changed by the project, use Sections
720.03(5)(c) and 1020.03(2) for vertical clearance requirements.

Include vertical clearance and any other changed geometrics in the Basis of Design, the
Design Parameters sheets, and the Design Documentation Package.

See DM Section 720.03(5)(c) for details about bridge clearances for existing structures and
Section 1020.03(2) for vertical clearance of overhead sign assemblies.

Page 1120-2 WSDOT Design Manual M 22-01.18

December 2019
Chapter 1120 Preservation Projects

Contact the Commercial Vehicle Services Office when changes to vertical clearance are
planned.

1120.03(6) Delineation
Install and replace delineation in accordance with Chapter 1030 (this includes pavement
markings, guideposts, and barrier delineation).

1120.03(7) Barriers and terminals

When the preservation project design, other than a chip seal or BST, will affect the
elevation of the pavement adjacent to a guardrail, terminal, and/or transition, measure
the height of those systems within the project limit and adjacent to pavement edges,
curbs, or sidewalks prior to construction. Measure the height to the top of the rail
element from the outside paved shoulder edge when no curb is present, from the gutter
line when guardrail is set above a curb, or from the sidewalk elevation if set behind a
sidewalk. Guidance for this situation:
 When the height of existing Type 1 guardrail, crashworthy terminals, and/or
transitions will fall outside the height range from 26.5” to 31” (26.5” to 30” for
terminals) in the project’s completed condition; the existing guardrail, terminals,
and/or transitions must be adjusted to a minimum height of 28” up to a maximum
height of 30”. This includes buried terminals that slope down such that the guardrail
height is reduced to less than 26.5-inches (measured in relation to a 10H:1V line
extended from the breakpoint at edge of shoulder). See Section 1610.04(3) for
acceptable options to raise standard runs of guardrail, and Section 1610.04(5) for
raising guardrail terminals. Replace the Type 1 guardrail system with a Type 31
guardrail system if its height cannot be adjusted to fall within the specified range.
 When the height of existing Type 31 guardrail, crashworthy terminals, and/or
transitions will fall outside the height range from 28” to 32” in the project’s
completed condition; the existing guardrail, terminals, and/or transitions must be
adjusted to a height of 31”. This includes buried terminals that slope down such that
the guardrail height is reduced to less than 28-inches (measured in relation to a
10H:1V line extended from the breakpoint at edge of shoulder). See Section
1610.04(3) for acceptable options to raise standard runs of guardrail, and
1610.04(5) for raising guardrail terminals. Replace the existing Type 31 guardrail
system with a new Type 31 guardrail system if its height cannot be adjusted to fall
within the specified range.
 When non-crashworthy terminals need to be raised, replace them with crashworthy
terminals. Provide replacement terminals in accordance with 1610.04(5)(a or b).
Non-crashworthy terminals and anchors that are effectively shielded by another
barrier do not warrant replacement.
 When guardrail needs to be raised, evaluate the guardrail length of need in
accordance with Chapter 1610. Notify Region Program Management if the length of
need extension will be longer than 250 feet. Extending length of need further than
250 feet is beyond the scope of the pavement preservation.

WSDOT Design Manual M 22-01.18 Page 1120-3

December 2019
Preservation Projects Chapter 1120

 Note that removal is an option if guardrail is no longer needed based on the

guidance in Chapters 1600 and 1610. Document the location of removal and the
reasoning for removal in the Design Documentation Package.
 When adjusting terminals that are equipped with CRT posts, the top-drilled holes in
the posts need to be at the surface of the ground.
 Pre-cast concrete barrier sections (either New Jersey or “F” shape) are normally
installed at a 32” height, which includes provision for up to a 3” overlay. A 29”
minimum height for this type of barrier must be maintained following an overlay.
 Single slope concrete barrier may be pre-cast or cast in place, and is installed new at
a height of 42”, 48”, or 54”. A 30” minimum height must be maintained for this type
of barrier following an overlay.

1120.03(8) Pavement Edge Treatment

Adding a pavement edge treatment is a low-cost feature to improve safety performance for
errant vehicles that depart and try to reenter the roadway. A pavement edge treatment can
also help maintain the structural integrity of the roadway and pavement performance at the
edge of the roadway by resisting the start of pavement cracking and/or pavement raveling.

Where practicable, install a pavement edge treatment at locations where asphalt concrete
pavement is applied to the outside edge of the existing pavement. Examples where
pavement edge treatment may not be practicable include, locations with roadside barrier
and/or curb. After installing the pavement edge treatment, trim shoulders with material that
is graded back over the edge treatment and flush with the paved roadway surface.

For more information about pavement edge treatment, contact the HQ Design Office, and
visit the FHWA website at:

https://www.fhwa.dot.gov/innovation/everydaycounts/edc-1/safetyedge.cfm

1120.04 Documentation
For Roadway Preservation (P1) projects, use the Basis of Design and Design Parameter Sheets
to document decisions when the project changes design elements that are not listed in
1120.03(1) through 1120.03(8).

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December 2019
Chapter 1210 Geometric Plan Elements
1210.01 General
1210.02 Horizontal Alignment
1210.03 Distribution Facilities
1210.04 Number of Lanes and Arrangement
1210.05 Pavement Transitions
1210.06 Procedures
1210.07 Documentation
1210.08 References

1210.01 General
This chapter provides guidance on the design of horizontal alignment, frontage roads, number
of lanes, arrangement of lanes, and pavement transitions. For additional information, see the
following chapters:

Chapter Subject
1230 Lane and shoulder widths
1240 Lane widths on turning roadways for full design level
1250 Superelevation rate and transitions
1260 Sight distance
1310 Guidelines for islands
1360 Ramp lane and shoulder guidelines

1210.02 Horizontal Alignment

1210.02(1) General
Horizontal and vertical alignments (see Chapter 1220) are the primary controlling elements for
highway design. It is important to coordinate these two elements with design speed, drainage,
intersection design, and aesthetic principles in the early stages of design. How horizontal
alignments are designed depends largely on the context and selected design controls. Lower-
speed environments can be more forgiving than higher-speed environments.

1210.02(1)(a) Low-Speed Alignments

Consider the following when designing low-speed horizontal alignments:

a. Determine whether sufficient contextual elements exist within the roadway cross
section to indicate the desired low-speed environment (street trees, lack of building
setbacks, streetside amenities, etc.).
b. Determine whether horizontal geometric traffic calming treatments will be needed to
maintain the selected design speed (see Chapter 1103).
c. Avoid placing pedestrian midblock crossings within horizontal curves.

WSDOT Design Manual M 22-01.12 Page 1210-1

November 2015
Geometric Plan Elements Chapter 1210

1210.02(1)(b) High-Speed Alignments

Horizontal alignments designed for high speed are likely to have modal priorities for freight and
passenger vehicles, and it is necessary to strive for forgiving and predictable alignments within
high-speed environments. Exhibits 1210-2a through 1210-2c show desirable and undesirable
alignment examples for use with the following considerations:

a. Make the highway alignment as direct as practicable and still blend with the topography
while considering developed and undeveloped properties, community boundaries, and
environmental concerns.

b. Make highway alignment consistent by:

• Using gentle curves at the end of long tangents.
• Using a transition area of moderate curvature between the large radius curves
of rural areas and the small radius curves of populated areas.
• Making horizontal curves visible to approaching traffic.

c. Avoid minimum radii and short curves unless:

• Restrictive conditions are present and alternatives are not readily or economically
avoidable.
• On two-lane highways, minimum radii result in tangent sections long enough for
needed passing.

d. Avoid any abrupt change in alignment. Design reverse curves with an intervening tangent
long enough for complete superelevation transition for both curves. (See Chapter 1250 for
more information on superelevation transitions.)

e. Avoid the use of curves in the same direction connected by short tangents (broken back
curves); substitute a single larger curve.

f. Avoid compound curves on open highway alignment if a simple curve can be obtained.
When compound curves are used, make the shorter radius at least two-thirds the longer
radius. Make the total arc length of a compound curve not less than 500 feet.

g. On divided multilane highways, take advantage of independent alignment to produce a

flowing alignment along natural terrain.

h. The desirable locations for bridges, interchanges, intersections, and temporary connections
are on tangent sections in clear view of drivers.

i. On two-lane two-way highways, strive for as much passing sight distance as possible (see
Chapter 1260).

1210.02(2) Horizontal Curve Radii

Design speed is the governing variable of horizontal curves. For guidance regarding design speed
selection, see Chapter 1103, and see Chapter 1360 for ramps.

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Chapter 1210 Geometric Plan Elements

Use the following factors to determine the radius for a curve:

• Low to intermediate design speed environments may need to utilize horizontal curves
to maintain the desired operating speed. Horizontal curvature, more than any other
design element or treatment, provides the best speed management results. (See
Chapter 1103 for more information on speed management.)
• Stopping sight distance where sight obstructions are on the inside of a curve. Median
barriers, bridges, walls, cut slopes, wooded areas, buildings, and guardrails are
examples of sight obstructions. (See Chapter 1260 to check for stopping sight distance
for the selected design speed.)
• Superelevation is the rotation or banking of the roadway cross section to overcome
part of the centrifugal force that acts on a vehicle traversing a curve. Design
information on the relationship between design speed, radius of curve, and
superelevation is in Chapter 1250.
• Coordinate vertical and horizontal alignment (see Chapter 1220).

Spiral curves, although no longer used on new highway construction or major realignment, still
exist on Washington’s highways. Spirals were used to transition between tangents and circular
curves with the horizontal curvature rate increasing from tangent to the central curve and
decreasing from curve to tangent. Spirals do not pose an operational concern and may remain
in place. (See A Policy on Geometric Design of Highways and Streets for information on spirals.)

1210.02(3) Horizontal Curve Length

A curve is not required for small deflection angles. Exhibit 1210-1 gives the maximum allowable
angle without a curve. (See Chapter 1310 for guidance on angle points or short radii curves in
the vicinity of intersections at grade.)

To avoid the appearance of a kink in the road, the desirable length of curve for deflection angles
larger than given in Exhibit 1210-1 is at least 500 feet.
Exhibit 1210-1 Maximum Angle Without Curve

Design Speed Maximum Angle

(mph) Without Curve
25 2°17’
30 1°55’
35 1°38’
40 1°26’
45 1°16’
50 1°09’
55 1°03’
60 0°57’
65 0°53’
70 0°49’
75 0°46’
80 0°43’

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November 2015
Geometric Plan Elements Chapter 1210

1210.03 Distribution Facilities

1210.03(1) General
In addition to the main highway under consideration, other facilities can be used to distribute
traffic to and from the highway and to provide access. Highway flexibility can be augmented by:
• Frontage roads
• Collector-distributor roads
• On and off connections
• Parallel arterial routes with connections between them and the main highway
• Loop highways around large metropolitan areas

A city or county may be asked to accept a proposed distribution facility as a city street or county
road. Plan and design these facilities according to the applicable design values as city streets or
county roads (see Chapter 1230).

1210.03(2) Frontage Roads

Frontage roads constructed as part of highway development may serve to:
• Reestablish continuity of an existing road severed by the highway.
• Provide service connections to adjacent property that would otherwise be isolated
as a result of construction of the highway.
• Control access to the highway.
• Maintain circulation of traffic on each side of the highway.
• Segregate local traffic from the higher speed through traffic and intercept driveways
of residences and commercial establishments along the highway.
• Relieve congestion on the arterial highway during periods of high use or in emergency
situations.

Frontage roads are generally not permanent state facilities. They are usually turned back to the
local jurisdiction. Plan and design frontage roads as city streets or county roads (see Chapter
1230). Initiate coordination with the local agency that will be the recipient of the facility early
in the planning process, and continue through design and construction. (See Chapter 530 for
additional guidance on frontage roads and turnbacks.)

Outer separations function as buffers between the through traffic on the highway and the
local traffic on the frontage road. The width is governed by requirements for grading, signing,
barriers, aesthetics, headlight glare, and ramps. Where possible, make the separation wide
enough to allow for development on both sides of the frontage road. Wider separations also
move the intersection with the frontage road and a crossroad farther from the intersection
with the through roadway, and they can reduce the amount of limited access control rights
to be acquired (see Chapter 530).

Where two-way frontage roads are provided, make the outer separation wide enough to
minimize the effects of approaching traffic on the right, particularly the headlight glare. (See
Chapter 1600 for information on headlight glare considerations.) With one-way same-direction
frontage roads, the outer separation need not be as wide as with two-way frontage roads.

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Chapter 1210 Geometric Plan Elements

Wide separations lend themselves to landscape treatment and can enhance the appearance of
both the highway and the adjoining property.

A substantial width of outer separation is particularly advantageous at intersections with cross

streets. The wider separation reduces conflicts with pedestrians and bicycles.

Where ramp connections are provided between the through roadway and the frontage road,
the minimum outer separation width depends on design of the ramp termini.

1210.04 Number of Lanes and Arrangement

1210.04(1) General
The basic number of lanes is designated and maintained over a length of highway. The total
number of lanes is the basic number of lanes plus any auxiliary lanes provided to meet:
• Level of service (volume-capacity)
• Lane balance
• Flexibility of operation

1210.04(2) Basic Number of Lanes

In certain situations, it is appropriate to keep the basic number of lanes constant over a highway
route, or a significant portion thereof, regardless of changes in traffic volume. However, this can
lead to unnecessary property or environmental impacts that need to be balanced throughout a
design. Consider the impacts, human factors, and traffic analysis before making decisions
regarding basic number of lane consistency throughout a highway route.

Change the basic number of lanes for general changes in traffic volume over a substantial length
of the route. The desirable location for a reduction in the basic number of lanes is on a tangent
section between interchanges or intersections. However, there can be advantages in using
dedicated turn lanes at intersections as a means to reduce the number of lanes.

To accommodate high traffic volumes for short distances, such as between adjacent
interchanges, use auxiliary lanes. When auxiliary lanes are provided on consecutive sections
between interchanges, consider increasing the basic number of lanes through the entire length.

1210.04(3) Auxiliary Lanes

Auxiliary lanes are added to the basic number of lanes to allow additional traffic movements on
short segments. These added lanes are based primarily on volume-to-capacity relationships (see
Chapter 320). For efficient operation of auxiliary lanes, see the following:

Chapter Subject
1270 Truck climbing and passing lanes
1310 Left- and right-turn lanes and storage for turning
1360 Weaving and auxiliary lanes associated with interchanges

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1210.05 Pavement Transitions

1210.05(1) Lane Transitions
1210.05(1)(a) Change Lane Width
For lane width changes that create an angle point in an adjacent lane, the maximum angle is
given in Exhibit 1210-1. When a lane width change does not create an angle point in an adjacent
lane, a 25:1 taper is sufficient.

1210.05(1)(b) Reduce Number of Lanes

To reduce the number of lanes, provide a transition with the following guidelines:
• Locate transitions where decision sight distance exists, desirably on a tangent section
and on the approach side of any crest vertical curve, except the end of climbing lanes,
which are transitioned in accordance with Chapter 1270.
• Supplement the transition with traffic control devices.
• Reduce the number of lanes by dropping only one at a time from the right side in the
direction of travel. (See the MUTCD when dropping more than one lane in a single
direction.)
• Use the following formula to determine the minimum length of the lane transition for
speeds 45 mph or more:

L  VT
Where:
L = Length of transition (ft)
V = Design speed (mph)
T = Tangential offset width (ft)

• Use the following formula to determine the minimum length of the lane transition for
speeds less than 45 mph:

L = TV2
60
Where:
L = Length of transition (ft)
V = Design speed (mph)
T = Tangential offset width (ft)

1210.05(1)(c) Increase Number of Lanes

To increase the number of lanes, a tangential rate of change in the range of 1:4 to 1:15 is
sufficient. Aesthetics are the main consideration.

1210.05(1)(d) Turning Roadway

For turning roadway widening width transitions, see Chapter 1240.

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Chapter 1210 Geometric Plan Elements

1210.05(2) Median Width Transitions

Whenever two abutting sections have different median widths, use long, smooth transitions
(L = VT or flatter). When horizontal curves are present, this can be accomplished by providing
the transition throughout the length of the curve. For transitions on tangent sections, the
transitions may be applied symmetrically about the centerline or on only one side of the median
based on whether or not the abutting existing section is programmed for the wider median in
the future. For aesthetics, make the transition length as long as feasible.

1210.06 Procedures
When the project realigns the roadway, develop horizontal alignment plans for inclusion in the
Plans, Specifications & Estimates. Show the following as needed to maintain clarity and provide
necessary information:
• Horizontal alignment details (tangent bearing, curve radius, and superelevation rate)
• Stationing
• Number of lanes
• Intersections, road approaches, railroad crossings, and interchanges (see Chapters
1310, 1340, 1350, and 1360)
• Existing roadways and features affecting or affected by the project

For additional plan guidance, see the Plans Preparation Manual.

Justify any realignment of the roadway. Include the reasons for the realignment, profile
considerations, and alternatives considered, and the reasons the selected alignment was
chosen.

When the project changes the number of lanes, include a capacity analysis supporting the
number selected (see Chapter 320) with the justification for the number of lanes.

Include with the justification for a frontage road any traffic analyses performed; the social,
environmental, and economic considerations; the options considered; and the reasons for the
final decision.

1210.07 Documentation
Refer to Chapter 300 for design documentation requirements.

1210.08 References
1210.08(1) Federal/State Laws and Codes
Washington Administrative Code (WAC) 468-18-040, Design standards for rearranged county
roads, frontage roads, access roads, intersections, ramps and crossings

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1210.08(2) Design Guidance

Local Agency Guidelines (LAG), M 36-63, WSDOT

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

Plans Preparation Manual, M 22-31, WSDOT

Right of Way Manual, M 26-01, WSDOT

Utilities Manual, M 22-87, WSDOT

1210.08(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition

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Exhibit 1210-2a Alignment Examples

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Exhibit 1210-2b Alignment Examples

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Exhibit 1210-2c Alignment Examples

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Chapter 1220 Geometric Profile Elements
1220.01 General
1220.02 Vertical Alignment
1220.03 Coordination of Vertical and Horizontal Alignments
1220.04 Airport Clearance
1220.05 Railroad Crossings
1220.06 Procedures
1220.07 Documentation
1220.08 References

1220.01 General
Vertical alignment (roadway profile) consists of a series of gradients connected by vertical
curves. It is mainly controlled by the following:
• Topography
• Class of highway
• Horizontal alignment
• Safety
• Sight distance
• Construction costs
• Drainage
• Adjacent land use
• Vehicular characteristics
• Aesthetics

This chapter provides guidance for the design of vertical alignment. For additional information,
see the following chapters:

Chapter Subject
1103 Design controls, terrain
1210 Horizontal alignment
1260 Sight distance
1310 Grades at intersections
1360 Maximum grade for ramps

1220.02 Vertical Alignment

1220.02(1) Design Principles
The following are general principles for developing vertical alignment (also see Exhibits 1220-2a
through 2c):
• Use a smooth grade line with gradual changes, consistent with the context
identification and character of terrain. Avoid numerous breaks and short grades.

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• Avoid “roller coaster” or “hidden dip” profiles by use of gradual grades made possible
by heavier cuts and fills or by introducing some horizontal curvature in conjunction
with the vertical curvature.
• Avoid grades that affect truck speeds and, therefore, traffic operations.
• Avoid broken back grade lines with short tangents between two vertical curves.
• Use long vertical curves to flatten grades near the top of long, steep grades.
• Where at-grade intersections occur on roadways with moderate to steep grades, it
is desirable to flatten or reduce the grade through the intersection.
• Establish the subgrade at least 1 foot above the high water table (real or potential),
or as recommended by the Region Materials Engineer. Consider the low side of
superelevated roadways.
• When a vertical curve takes place partly or wholly in a horizontal curve, coordinate the
two as discussed in 1220.03.

1220.02(2) Minimum Length of Vertical Curves

The minimum length of a vertical curve is controlled by design speed, stopping sight distance,
and the change in grade. Make the length of a vertical curve, in feet, not less than three times
the design speed, in miles per hour. (See Chapter 1260 to design vertical curves to meet
stopping sight distance criteria.) For aesthetics, the desirable length of a vertical curve is two
to three times the length to provide stopping sight distance.

Sag vertical curves may have a length less than required for stopping sight distance when all
three of the following are provided:
• An analysis to justify the length reduction.
• Continuous illumination.
• Design for the comfort of the vehicle occupants. For comfort, use:

AV 2
L
46 .5
Where:
L = Curve length (ft)
A = Change in grade (%)
V = Design speed (mph)

The sag vertical curve lengths designed for comfort are about 50% of those for sight distance.

1220.02(3) Maximum Grades

Analyze grades for their effect on traffic operation because they may result in undesirable truck
speeds. Maximum grades are controlled by terrain type and design speed (see Grade and Speed
Considerations below and Chapters 1103 and 1360).

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1220.02(4) Minimum Grades

Minimum grades are used to meet drainage requirements. Avoid selecting a “roller coaster” or
“hidden dip” profile merely to accommodate drainage.

Minimum ditch gradients of 0.3% on paved materials and 0.5% on earth can be obtained
independently of roadway grade. Medians, long sag vertical curves, and relatively flat terrain are
examples of areas where independent ditch design may be justified. A closed drainage system
may be needed as part of an independent ditch design.

1220.02(5) Length of Grade

The desirable maximum length of grade is the maximum length on an upgrade at which a loaded
truck will operate without a 10 mph reduction. Exhibit 1220-1 gives the desirable maximum
length for a given percent of grade. When grades longer than the desirable maximum are
unavoidable, consider an auxiliary climbing lane (see Chapter 1270). For grades that are not at
a constant percent, use the average.

When long, steep downgrades are unavoidable, consider an emergency escape ramp, and for
grades longer than indicated, consider an auxiliary climbing lane (see Chapter 1270).
Exhibit 1220-1 Grade Length
9

7
Percent Upgrade

0
0 1,000 2,000 3,000
Desirable Maximum Length of Grade

For grades longer than indicated, consider an auxiliary climbing lane (see Chapter 1270).

1220.02(6) Grade and Speed Considerations

Grades can affect the operating performance of the vehicles negotiating them. The bicycle,
transit, and freight modes are most affected by grades, while passenger cars can readily
negotiate grades as steep as 5% without appreciable loss of operating speed. Steep downgrades
can also impact operating speeds, particularly for heavy trucks, which display up to a 5%
increase in speed on downgrades. Consider the selected performance for a location and corridor
before making a determination on grade selection, to avoid unnecessary cuts or fills required for
a vertical alignment. The following tables provide suggestions for determining maximum grades
based on the context, terrain classification, and targeted speed. However, these grades may
vary from these values depending on the performance targeted for a location.

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Table 1 Maximum Grades for Rural Contexts

Type of Design Speed (mph)

Terrain 25 30 35 40 45 50 55 60 65 70 75 80
Level 6-7 6-7 6-7 5-7 5-7 4-6 4-6 3-5 3-5 3-4 3 3
Rolling 8-10 7-9 7-9 6-8 6-8 5-7 5-7 4-6 4-6 4-5 4 4
Mountainous 9-11 8-10 8-10 8-10 7-10 7-9 6-9 6-8 5-8 5-6 5 5

Table 2 Maximum Grades for Suburban and Urban Contexts

Design Speed (mph)

Type of Terrain
20 25 30 35 40 45 50 55 60
Level 8-9 8-9 8-9 7-9 7-9 6-8 6-7 5-7 5-6
Rolling 11-12 11-12 9-11 8-10 8-10 7-9 7-8 6-8 6-7
Mountainous 13-14 12-13 11-12 10-12 10-12 9-11 9-10 8-10 8-9

Table 3 Maximum Grades for Interstate and Full Limited Access Control Facilities

Design Speed (mph)

Type of Terrain
50 55 60 65 70 75 80
Level 4 4 3 3 3 3 3
Rolling 5 5 4 4 4 4 4
Mountainous 6-7 6-7 6-7 6-7 5-6 5-6 5-6

1220.02(6) Alignment on Structures

Where practicable, avoid high skew, vertical curvature, horizontal curvature, and superelevation
on structures, but do not sacrifice safe roadway alignment to achieve this.

1220.03 Coordination of Vertical and Horizontal Alignments

Do not design horizontal and vertical alignments independently. Coordinate them to obtain
uniform speed, pleasing appearance, and efficient traffic operation. Coordination can be
achieved by plotting the location of the horizontal curves on the working profile to help
visualize the highway in three dimensions. Perspective plots will also give a view of the
proposed alignment. Exhibits 1220-2a and 2b show sketches of desirable and undesirable
coordination of horizontal and vertical alignment.

Guides for the coordination of the vertical and horizontal alignment are as follows:
• Balance curvature and grades. Using steep grades to achieve long tangents and flat
curves or excessive curvature to achieve flat grades are both poor designs.
• Vertical curvature superimposed on horizontal curvature generally results in a more
pleasing facility. Successive changes in profile not in combination with horizontal
curvature may result in a series of dips not visible to the driver.
• Do not begin or end a horizontal curve at or near the top of a crest vertical curve.
A driver may not recognize the beginning or ending of the horizontal curve, especially
at night. An alignment where the horizontal curve leads the vertical curve and is longer
than the vertical curve in both directions is desirable.

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• To maintain drainage, design vertical and horizontal curves so that the flat profile of
a vertical curve is not located near the flat cross slope of the superelevation transition.
• Do not introduce a sharp horizontal curve at or near the low point of a pronounced sag
vertical curve. The road ahead is foreshortened and any horizontal curve that is not flat
assumes an undesirably distorted appearance. Further, vehicular speeds, particularly
of trucks, often are high at the bottom of grades and erratic operation may result,
especially at night.
• On two-lane roads, the need for passing sections (at frequent intervals and for an
appreciable percentage of the length of the roadway) often supersedes the general
desirability for the combination of horizontal and vertical alignment. Work toward
long tangent sections to secure sufficient passing sight distance.
• On divided highways, consider variation in the width of medians and the use of
independent alignments to derive the design and operational advantages of one-
way roadways.
• Make the horizontal curvature and profile as flat as practicable at intersections where
sight distance along both roads is important and vehicles may have to slow or stop.
• In residential areas, design the alignment to minimize nuisance factors to the
neighborhood. Generally, a depressed facility makes a highway less visible and less
noisy to adjacent residents. Minor horizontal adjustments can sometimes be made
to increase the buffer zone between the highway and clusters of homes.
• Design the alignment to enhance attractive scenic views of the natural and constructed
environment, such as rivers, rock formations, parks, and outstanding buildings.

When superelevation transitions fall within the limits of a vertical curve, plot profiles of the
edges of pavement and check for smooth transitions.

1220.04 Airport Clearance

Contact the airport authorities early for proposed highway construction or alteration in the
vicinity of a public or military airport, so that advance planning and design work can proceed
within the required Federal Aviation Administration (FAA) regulations (see the Environmental
Manual).

1220.05 Railroad Crossings

When a highway crosses a railroad at grade, design the highway grade to prevent low-hung
vehicles from damaging the rails or getting hung up on the tracks. Exhibit 1220-3 gives guidance
on designing highway grades at railroad crossings. For more information on railroad-highway
crossings, see Chapter 1350.

1220.06 Procedures
When the project modifies the vertical alignment, develop vertical alignment plans for inclusion
in the Plans, Specifications, and Estimates (PS&E) to a scale suitable for showing vertical
alignment for all proposed roadways, including ground line, grades, vertical curves, and
superelevation. (See the Plans Preparation Manual for guidance.)

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Geometric Profile Elements Chapter 1220

When justifying any modification to the vertical alignment, include the reasons for the change,
alternatives addressed (if any) and why the selected alternative was chosen. When the profile
is a result of new horizontal alignment, develop vertical and horizontal alignments together, and
include the profile with the horizontal alignment justification.

1220.07 Documentation
Refer to Chapter 300 for design documentation requirements.

1220.08 References
1220.08(1) Federal/State Laws and Codes
Washington Administrative Code (WAC) 468-18-040, Design standards for rearranged county
roads, frontage roads, access roads, intersections, ramps and crossings

1220.08(2) Design Guidance

Local Agency Guidelines (LAG), M 36-63, WSDOT

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

Plans Preparation Manual, M 22-31, WSDOT

1220.08(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition

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Chapter 1220 Geometric Profile Elements

Exhibit 1220-2a Coordination of Horizontal and Vertical Alignments

Horizontal curve

Crest vertical curve

Coinciding Horizontal and Crest Vertical Curves

When horizontal and crest vertical curves coincide, a satisfactory appearance results.

Horizontal curve

Sag vertical curve

Coinciding Horizontal and Sag Vertical Curves

When horizontal and sag vertical curves coincide, a satisfactory appearance results.

Horizontal alignment

Crest vertical curve

Short Tangent on a Crest Between Two Horizontal Curves

This combination is deficient for several reasons:

• The curve reversal is on a crest, making the second curve less visible.
• The tangent is too short for the superelevation transition.
• The flat area of the superelevation transition will be near the flat grade in the crest.

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Geometric Profile Elements Chapter 1220

Exhibit 1220-2b Coordination of Horizontal and Vertical Alignments

Horizontal tangent

Desirable profile

Profile

Profile With Tangent Alignment

Avoid designing dips on an otherwise long uniform grade.

Horizontal curve

Sag vertical curve

Sharp Angle Appearance

This combination presents a poor appearance. The horizontal curve looks like a sharp angle.

Horizontal alignment
Perspective
Line of sight

Profile

Disjointed Effect
A disjointed effect occurs when the beginning of a horizontal curve is hidden by an intervening crest while the
continuation of the curve is visible in the distance beyond the intervening crest.

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Exhibit 1220-2c Coordination of Horizontal and Vertical Alignments

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Exhibit 1220-3 Grading at Railroad Crossings

30 ft

A A

30 ft

Rails

30 ft

Level 3 in max

3 in max

Limits of roadway surface

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Chapter 1230 Geometric Cross Section Basics
1230.01 General
1230.02 Guidance for Specific Facility Types
1230.03 Common Elements
1230.04 Jurisdiction for Design and Maintenance
1230.05 References

When choosing any geometric cross section dimension, including lane or shoulder width, read the
guidance that is specific to the facility type. Also, read the general guidance related to common
elements such as lanes, shoulders, side slopes, etc.

See Chapter 1106 for the general dimensioning guidance.

This chapter also contains guidance related to jurisdiction.

1230.01 General
The geometric cross section is composed of multiple lateral design elements such as lanes,
shoulders, medians, bike facilities, and sidewalks. The designer’s task is to select, size, and
document these elements appropriately. There is flexibility in the selection of design element
dimensioning.

All WSDOT routes, regardless of context, are referred to in the Design Manual as “highways.”
Under this definition, freeways are a subset of highways while Interstate freeways are one
specific type of freeway.

Refer to the Design Manual Glossary for many of the terms used in this chapter. See Chapter
300 for design documentation requirements.

1230.02 Guidance for Specific Facility Types

Guidance regarding geometric cross sections is located in various Design Manual chapters. The
chapter depends on the facility type. Examples of specific facility types include:
• Highways (general) • Median U-turns and crossovers
• Freeways • Transit facilities including bus pull-outs
• Ramps • Enforcement areas
• Auxiliary lanes • Slow vehicle turn-outs
• Collector-Distributor lanes • Truck weighing facilities
• Service lanes • Shared use paths
• Frontage roads • Sidewalks
• HOV facilities • Bicycle Facilities

Exhibit 1230-1 shows some common facility types along with the corresponding chapter that
geometric cross section guidance can be found in.

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Geometric Cross Section Basics Chapter 1230

Exhibit 1230-1 Geometric Cross Section - Guide to Chapters

Lateral
Turning
Lane Shoulder Median clearance Side Cross
Facility Type roadway
width width width to curb or slope slope
width
barrier

Highways (General) 1231 1240 1231 1239 1239 1239 1250

Freeways 1232 1240 1232 1239 1239 1239 1250

1360 &
Ramps 1360 1240 1360 1360 1239 1239
1250
1270 or 1270 or
Auxiliary lanes [1] 1240 [1] N/A 1239 1239 1270
1360 1360

C-D roadways 1360 1240 1360 N/A 1239 1239 1360

HOV lanes, ramp bypass 1410 &
1410 1410 1410 N/A 1239 1410
lanes, etc. 1239
Left-side direct HOV 1420 (for 1420 &
1420 1420 1420 1239 1250
access (DHOV) facilities DHOV) 1239
Shared use path 1515 1515 1515 N/A 1515 1515 1515

Geometric cross section guidance for other special purpose facilities is in various
chapters. Examples include special use lanes, bridges, transit facilities, bus pull
Other
outs, median U-turns and crossovers, enforcement areas, truck weighing facilities,
pedestrian bridges and tunnels, sidewalks & bicycle facilities
Notes:
General guidance for curb design is in Chapter 1239. Guidance for curb is also found for numerous
types of facilities (Chapter 1310 and others.)
[1] Passing and climbing lanes, see Chapter 1270; Auxiliary lanes between interchanges see Chapter
1360.

Exhibit 1230-1 is not a comprehensive list of guidance associated with either a facility or a
design element. It is intended to be a quick reference to the chapter containing the primary
guidance related to the specific element and facility type.

For guidance related to intersections see Chapter 1310. For guidance related to sidewalks see
Chapter 1510. For guidance related to bicycle facilities see Chapter 1520. For guidance related
to bridges see Chapter 720.

1230.03 Common Elements

In addition to the guidance specific to the facility type, also see the general guidance related to
cross-sectional elements that are common to various facility types:
 Lanes Chapter 1231
 Shoulders, side slopes, medians & curbs Chapter 1239
 Lateral clearance to curb and barrier Chapter 1239
 Parking & streetside (behind the curb) elements Chapter 1238
 Cross slope and superelevation Chapter 1250

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Chapter 1230 Geometric Cross Section Basics

1230.04 Jurisdiction for Design and Maintenance

On all state highways in locations outside of cities or towns and within limited access design
areas, geometric design is to be consistent with this Design Manual.
On state highways within an incorporated city or town, develop design features in cooperation
with the local agency. For NHS routes, use the Design Manual. For non-NHS routes, the Local
Agency Guidelines may be used for dimensioning design elements
Cross-sectional design within incorporated cities or towns can get complicated due to the joint-
jurisdictional authority. WSDOT typically has jurisdiction between the backs of curbs, and cities
typically have jurisdiction outside the backs of curbs (see Exhibit 1230-2). When no curb is
present, the city or town holds responsibility for the roadside outside the paved shoulder.
Despite the jurisdictional differences, it is extremely important to cooperatively determine a
cross-sectional design.
Refer to Chapter 301 for additional information on jurisdictional maintenance responsibilities
and considerations for maintenance agreements.

Exhibit 1230-2 State and City Jurisdictional Responsibilities

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1230.05 References
1230.05(1) Design Guidance
Highway Runoff Manual, M 31-16, WSDOT

Local Agency Guidelines (LAG), M 36-63, WSDOT

Plans Preparation Manual, M 22-31, WSDOT

Standard Plans for Road, Bridge, and Municipal Construction, M 21-01, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction, M 41-10, WSDOT

1230.05(2) Supporting Information

Understanding Flexibility in Transportation Design – Washington, WA-RD 638.1, Washington
State Department of Transportation, 2005
 www.wsdot.wa.gov/research/reports/fullreports/638.1.pdf

Urban Street Design Guide, National Association of City Transportation Officials, New York, NY,
2013
 www.nacto.org

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition
Available from the WSDOT Library.

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Chapter 1231 Geometric Cross Section – Highways
1231.01 General
1231.02 Design Up
1231.03 Common Elements
1231.04 Vehicle Lanes
1231.05 Modally Integrated Cross Sections
1231.06 Road Diets and Retrofit Options
1231.07 References

1231.01 General
Geometric cross sections for state highways are governed by the need to balance performance
metrics, the context, and selected design controls. The objective is to optimize the use of
available public space while avoiding an unreasonable investment in right of way acquisition.

The term “highways” refers to all WSDOT roadways, including freeways. However, note that
freeways have their own geometric cross section guidance. This chapter is not intended for
freeway design. See Chapter 1232 for freeways.

1231.02 Design Up
Unless otherwise specified, use the “design up” method described in Chapter 1106 to choose a
design element width when a range of widths is given in this chapter.

1231.03 Common Elements

The geometric cross sections shown in this chapter have many elements that are also common
to facilities addressed in other chapters. The following chapters contain guidance related to
these common geometric cross section elements:
 Lanes Chapter 1231
 Shoulders, side slopes & ditches, medians & curbs Chapter 1239
 Lateral clearance to curb or barrier Chapter 1239
 Parking & streetside (behind the curb) elements Chapter 1238
 Cross slope and superelevation Chapter 1250

1231.04 Vehicle Lanes

1231.04(1) Type of Lanes

There are many types of lanes that may exist in a cross section, and each has its own purpose
and sizing needs. General-purpose traffic lanes need to accommodate a variety of vehicle types
including buses, freight vehicles, personal automotive vehicles, and bicycles. The target speed,
modal priority, balance of performance needs, and transportation context are all considerations
when determining size, type, and number of lanes.

Some common types of vehicle lanes include:

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Geometric Cross Section – Highways Chapter 1231

Through Lanes

Through lanes are the most common lane type. All highways have at least one lane in each
direction to provide unimpeded traffic flow from Point A to Point B.

Turn Lanes

Dedicated turn lanes are separated from the through lanes and provide storage for turning
vehicles waiting for a signal or gap in opposing traffic. There are a number of different types of
turn lanes which are discussed in detail in Chapter 1310. Turn lanes are critical to meet mobility
and accessibility performance for motorized and bicycle modes. Traffic analysis determines the
type, storage length, and number of turn lanes that are needed to achieve the balance of
multimodal performance needs.

Turn lanes present potential conflicts, particularly with bicyclists and pedestrians. See Chapters
1510 and 1520 for additional discussion on ways to mitigate for these conflicts.
Bicycle Lanes

There are several different types of bicycle lanes and many different ways to arrange bike lanes
within the geometric cross section (see Chapter 1520). Shoulders designed to function for bikes
are not considered bike lanes.
Transit-Only Lanes

Transit-only lanes are ideal for improving transit mobility performance and segregating heavily
used or complex intermodal connections. There are many different ways to configure these
within a geometric cross section. Some configurations are limited due to passenger loading
needs for both the transit vehicle type and the stop locations. Develop widths for transit-only
lanes with the partnering transit agency. See Chapter 1430 for additional information on Transit
Facility considerations.

Auxiliary lanes

Auxiliary lanes enhance mobility performance for motor vehicles. See Chapter 1270 for design
guidance and a detailed discussion on the types of auxiliary lanes.

Managed and Shared Lanes

There are many different types of managed and shared lanes. Some examples include:
 High occupancy vehicle (HOV) lanes (see Chapter 1410)
 High occupancy toll lanes (discuss with Tolling Division and see Chapter 1410)
 Hard shoulder running
 Peak hour use
 Bicycle shared lane (see Chapter 1520)
 Business access and transit (BAT) lane (see Chapter 1410, Arterial Street HOV)

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1231.04(2) Lane Width

Lane width ranges for highways are listed in Exhibit 1231-1.
Exhibit 1231-1 Lane Widths for Highways

Speed Highway Type Lane Width Range*

Freeway (incl. Interstate) See Chapter 1232
High Speed
Other Highway 11' - 12'
Intermediate Speed All 11' - 12'
Low Speed All 10' - 12'

* The width shown is exclusive of the gutter if the gutter is a color that contrasts with the
roadway.

1231.04(2)(a) Lane Width Considerations

Exhibit 1231-2 lists some considerations that may be helpful in choosing the most appropriate
lane width from the range given in Exhibit 1231-1. This is not a comprehensive list. The
considerations listed are meant to help understand the modal needs and function associated
with different lane widths. Work with your Region Traffic Office when choosing lane widths.

Exhibit 1231-2 Lane Width Considerations

Lane Width Considerations

Roadways on curves, see Chapter 1240 Turning Roadway Widths
Narrower lanes may be used as part of a speed reduction strategy
Two-lane, two-way rural highways: 12 ft lanes provide clearance between large vehicles
General

traveling in opposing directions. Especially beneficial when high volumes or high truck
percentages expected
On multilane facilities with width constraints, utilizing narrower inside lanes may permit wider
outside lanes for bicycles, freight, and transit
Reduced lane widths allow more lanes to be provided in areas with constraints and allow
shorter pedestrian crossing times because of reduced crossing distances

12 ft lanes provide increased benefit on high speed, free-flowing principle arterials

Intermediate to
High Speed

12 ft lanes provide increased benefit where there are higher truck volumes, especially for
intermediate and high speed facilities
Safety and mobility performance difference between 11 ft and 12 ft lanes can be negligible.
Work with Region Traffic Office to evaluate performance differences for the subject roadway

11 ft lanes are common on urban arterials

Low Speed

Lane widths of 10 ft may be appropriate in constrained areas with low truck and bus volume

In pedestrian oriented sections, 10 ft lanes can be beneficial in minimizing crossing distance

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1231.05 Modally Integrated Cross Sections

WSDOT’s goal is to optimize existing system capacity through better interconnectivity of all
transportation modes. Choosing the appropriate geometric cross section relies heavily on
designing for the appropriate modes. See Chapter 1103 for guidance in selecting modes to
accommodate and choosing modal priorities.

Once a decision is made regarding which modes to accommodate and which modes will have
priority, a geometric cross section can be developed. The cross sections in this chapter are
organized by modal priority for the following primary modes:

Motor Vehicles, including freight

Bicycles

Pedestrians

Transit

The cross-section examples shown in Exhibits 1231-3 through 1231-7 depict various
combinations of elements that may be included in a cross section. The examples are intended to
stimulate designer creativity and awareness of modal accommodations, and are not intended to
be standard cross sections to be reproduced for a given modal priority. It is expected that
innovative project alternatives will result in diverse configurations that best balance baseline
and contextual needs (see Chapter 1101).

Since the cross-sections shown are only examples, and are really combinations of various
elements, it is important to read the guidance associated with the specific elements (see
1231.03) in order to understand the considerations that may affect a choice of width, and to
understand documentation requirements.

The cross section examples provide a range of dimensions for different design elements. See
Chapter 1106 for guidance regarding choosing a width when a range of widths is given.

Maintaining the continuity of a roadway is an important consideration, particularly for limited

access and other high-speed highways. However, it is also appropriate to change continuity as
context changes in order to influence driver behavior. When designing intentional changes to
the continuity of the geometric cross section, consider what is needed to enable the transition.
High-speed to low-speed changes will need to transition the geometric cross section over a
distance utilizing a speed transition segment (see Chapter 1103).

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1231.05(1) Auto-and Freight Oriented Cross Sections

Exhibit 1231-3 shows examples of motorized vehicle-oriented designs. Motorized vehicles come
in a variety of types which are operated on many vehicle lanes and parking areas. The
performance needs of freight and other automotive vehicle types are often similar. However,
certain truck vehicle types may require additional turning roadway width for off-tracking (see
Chapter 1240), or at other locations a truck climbing lane may be needed to facilitate mobility
performance (see Chapter 1270). Generally, lane width within suburban and urban contexts is
less critical for mobility and safety performance than in rural and high-speed contexts. Within
urban areas, placement of and sizing for loading areas within the parking areas can depend on
the freight vehicle type.

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Exhibit 1231-3 Motor Vehicle Oriented Cross Sections

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1231.05(2) Cross Sections Featuring Bicycle Facilities

Exhibit 1231-4 Example A features bicycle facilities at an intermediate-speed location. Bike lane
location within the cross section depends largely on how cyclists will interact with the land use
and potential modal conflicts. Locating bike lanes on the outside of the motor vehicle lanes can
improve accessibility for bicyclists. If cyclist mobility performance is a primary concern or
intermodal conflicts (such as transit stop locations) are present, locating bike facilities in the
center of the roadway may be more appropriate. Whether or not a bike lane buffer is needed
depends mostly on the target speed and average daily traffic (ADT) of the facility; the intent of
bike buffers or other protected bike facilities is to address safety performance for cyclists.
Buffers and other means of modal segregation also benefit motor vehicle drivers and
pedestrians by showing allocated spaces. Both roadway bike lane configurations and bike facility
selection are discussed in more detail in Chapter 1520.

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Geometric Cross Section – Highways Chapter 1231

Exhibit 1231-4 Cross Sections Featuring Bicycle Facilities

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Chapter 1231 Geometric Cross Section - Highways

1231.05(3) Cross Sections Featuring Pedestrian Facilities

Exhibit 1231-5 shows cross-section examples featuring pedestrian facilities. The pedestrian
mode is a vital transportation mode since, for most people, nearly every trip at least begins and
ends by walking. Roadway facilities prioritized for pedestrians emphasize streetside elements.
See Chapter 1238 for guidance regarding streetside elements.

The objective is to achieve the Pedestrian Circulation Path (PCP) necessary to support mobility,
socioeconomic, and accessibility needs and provide access to intermodal connections. The
configuration and dimension of streetside elements varies significantly depending on the
performance needs being addressed. See Chapter 1510 for additional pedestrian design
requirements and considerations.

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Exhibit 1231-5 Cross Sections Featuring Pedestrian Facilities

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Chapter 1231 Geometric Cross Section - Highways

1231.05(4) Cross Sections Featuring Transit Facilities

Exhibit 1231-6 provides examples of different potential configurations oriented for the transit
mode. Work with the transit provider to determine their ability to operate within a given cross-
sectional arrangement. In general, transit configurations can be positioned toward the side or
center of a roadway. Both side and center configurations can be implemented with medians or
outer separations to improve safety performance for intermodal connections, or mobility
performance for the transit service.

Exhibit 1231-6 Example A shows a central configuration for transit service that provides a
separated bus-only lane. Other transit vehicle types may require different widths and may also
require other center cross section configurations for passenger loading. Exhibit 1231-6 Example
B shows a side configuration where transit vehicles occupy the outside lane. This example can
also be configured as business access and transit [BAT] lanes. Note the importance of streetside
elements to assist with intermodal connections. Exhibit 1231-6 Example C is an example of a
type of special use lane for high-speed routes that are routinely congested. In this example, the
shoulder allows the restricted use for buses.

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Exhibit 1231-6 Cross Sections Featuring Transit Facilities

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1231.05(5) Example Cross-Sections – Complete Streets

Complete street configurations attempt to balance the performance needs of all users,
regardless of age, ability, or mode. The general intent is to provide context-appropriate designs
that enable safe access for all design users. It is always important to consider modal connectivity
and conflicts that may occur with complete street configurations, particularly at intersections
and/or transit stop locations.

There are different potential configurations for complete streets, such as:
 A rural two-lane highway with wide shoulders; the shoulders can be used by motor
vehicles in emergencies and by pedestrians and bicyclists.
 An urban highway or street with vehicle lanes, bike lanes, bus lanes, and sidewalks.
 Retrofitting a highway or street to clearly mark and sign a shared-use lane.
 An urban highway that undergoes a “road diet” (see 1231.06) or installation of
additional pedestrian crossings.

The low speed examples in Exhibit 1231-7 illustrate roadway cross sections that:
 Separate access lanes from through traffic lanes using curbed islands.
 Reduce conflicts between pedestrian, bike, transit and auto modes by separating them.
 Provide transit stops integrated with raised islands.
 May result in improved operations for all modes.

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Geometric Cross Section – Highways Chapter 1231

Exhibit 1231-7 Complete Street Cross Sections

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1231.06 Road Diets and Retrofit Options

Generally, road diets refer to converting four-lane undivided highways to three lanes with the
center lane for left turning movements and the remaining outside space repurposed for
bicyclists or other functions. The center lane can consist of a two-way left-turn lane (TWLTL) or
can be dedicated for directional left turns either by paint or other median treatments. The
choice of how to configure the center lane depends largely on balancing the resulting safety and
accessibility performance of different modes and land uses.

The application of road diets also

has the benefit of reallocating
existing space within a cross
section, which provides distinct
opportunities to improve
roadway bicycle facilities and/or
elements of the streetside. At
intersections and access points, a
road diet can improve sight
distance, may improve access
management along the road, and
in some cases, improve mobility
performance for motorists.

Typical Road Diet Basic Design from FHWA Road Diet Informational Guide

The success of road diet implementation varies due to a number of factors such as signal spacing
and timing, access connection density, modal priority, and average daily traffic (ADT). ADT is a
reasonable indicator for implementation. FHWA recommends limiting road diet applications to
roadways of 20,000 ADT or less, although road diets have been successful at locations with
25,000 ADT in various parts of the country (see Chapter 540 for additional restrictions on the
use of TWLTLs). Motor vehicle mobility performance is most likely deemed the primary measure
of success for the road diet configurations with higher ADT values described. However, locations
with a different modal priority and higher ADT may still be candidates for road diets. The Region
Traffic Engineer must approve road diet applications on state highways.

Retrofit options refer to the application of lower-cost treatments that utilize paint and other
delineation devices rather than hardscape features. See Chapter 1238 for more information on
retrofit options such as relocating the curb, parklets and plazas.

1231.07 References

1231.07(1) Design Guidance

Highway Runoff Manual, M 31-16, WSDOT

Local Agency Guidelines (LAG), M 36-63, WSDOT

Plans Preparation Manual, M 22-31, WSDOT

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Geometric Cross Section – Highways Chapter 1231

Standard Plans for Road, Bridge, and Municipal Construction, M 21-01, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction, M 41-10, WSDOT

1231.07(2) Supporting Information

FHWA Road Diet Informational Guide, FHWA, 2014
 www.safety.fhwa.dot.gov/road_diets/info_guide/

Understanding Flexibility in Transportation Design – Washington, WA-RD 638.1, Washington

State Department of Transportation, 2005
 www.wsdot.wa.gov/research/reports/fullreports/638.1.pdf

Urban Bikeway Design Guide, National Association of City Transportation Officials, New York,
NY, 2012 revised 2013
 www.nacto.org

Urban Street Design Guide, National Association of City Transportation Officials, New York, NY,
2013
 www.nacto.org

Designing Walkable Thoroughfares: A Context Sensitive Approach, Institute of Transportation

Engineers, Washington D.C., 2010.
 www.ite.org

Guide for Geometric Design of Transit Facilities on Highways and Streets, AASHTO, Washington,
D.C., 2011
 www.transportation.org/Pages/Default.aspx

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition
 www.transportation.org/Pages/Default.aspx

A Policy on Design Standards Interstate System, AASHTO, 2005

 www.transportation.org/Pages/Default.aspx

NCHRP Synthesis 443 – Practical Highway Design Solutions, Transportation Research Board,
Washington D.C., 2013
 http://www.trb.org/Main/Blurbs/168619.aspx

NCHRP Report 785 – Performance-Based Analysis of Geometric Design of Highways and Streets,
Transportation Research Board, Washington D.C., 2014
 www.trb.org/Main/Blurbs/171431.aspx

NCHRP Report 783 – Evaluation of the 13 Controlling Criteria for Geometric Design,
Transportation Research Board, Washington D.C., 2014
 www.trb.org/Main/Blurbs/171358.aspx

NCHRP Report 505 – Review of Truck Characteristics as Factors in Roadway Design,

Transportation Research Board, Washington D.C., 2003
 http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_505.pdf

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Chapter 1232 Geometric Cross Section – Freeways
1232.01 General
1232.02 Lane Width
1232.03 Shoulder Width
1232.04 Other Elements
1232.05 Design Flexibility
1232.06 References

If your roadway fits the definition of a freeway, use the guidance in this chapter for geometric cross-
section elements. If your roadway is not a freeway, see Chapter 1230.

1232.01 General
Freeways are defined as divided highways with a minimum of two lanes in each direction for the
exclusive use of vehicular traffic and with full control of access. Interstate is one type of freeway.

Freeways are high-speed facilities that prioritize through travel for vehicles, freight and transit.
Lanes must be wide enough for all vehicles that use them. Shoulders provide very important
functions for freeways.

Freeways can be thought of as a unique context. This is reflected by the fact that design controls
(Chapter 1103) are fairly consistent for all freeways:
 Modal priority: motor vehicles
 Access control: full control
 Design speed: high

Freeways do not present the challenges of accommodating the competing needs of other
modes such as pedestrians. Also, adjacent land use is generally not an issue due to freeways
being limited access facilities. For these reasons, choosing cross-sectional element dimensions
for freeways does not have as many complexities as for some other roadway types.

Note that there are locations where bicyclists are allowed use of the freeway shoulder.

The geometric cross-section for interstate freeways is shown in Exhibit 1232-1. The geometric
cross-section for non-interstate freeways is shown in Exhibit 1232-2.

Refer to the Design Manual Glossary for terms used in this chapter. Refer to Chapter 300 for
design documentation requirements.

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Exhibit 1232-1 Geometric Cross Section - Interstate (4 lanes shown, can vary)

Notes:
See Chapter 1410 for HOV lane guidance.
Use of the shoulder on a freeway for transit only use or as an HOV lane requires a Design Analysis.
[1] 4 ft minimum on facilities up to 4 lanes, and 10 ft minimum on 6-lane facilities.
In mountainous terrain, inside shoulder may be reduced to 4 ft on facilities up to 6 lanes.
[2] In mountainous terrain, outside shoulders may be reduced to 8 ft on facilities up to 6 lanes.
[3] Overall median width and design will vary. See Chapter 1239 and 1610.

Exhibit 1232-2 Geometric Cross Section – Non-Interstate (4 lanes shown, can vary)

Notes:
See Chapter 1410 for HOV lane guidance.
Use of the shoulder on a freeway for transit only use or as an HOV lane requires a Design Analysis.
[1] 4 ft minimum on facilities up to 4 lanes, and 8 ft minimum on 6-lane facilities.
In mountainous terrain, inside shoulder may be reduced to 4 ft on facilities up to 6 lanes
[2] Overall median width and design will vary. See Chapter 1239 and 1610.

Exhibit 1232-3 Median Section without Median Barrier

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Chapter 1232 Geometric Cross Section – Freeways

1232.02 Lane Width

For freeways, travel-through mobility and safety for motor vehicles are prioritized performance
areas. Lanes must be wide enough for all vehicles that use them to travel safely at high speeds.
When a range is given for lane width, use the mode/function/performance approach described
in Chapter 1106 and “design up” to choose a width within the range. See Chapter 1231 for
considerations for choosing a lane width.

1232.03 Shoulder Width

The prioritization of travel-through mobility and safety for motor vehicles results in placing a
high priority on providing some important shoulder functions (see Chapter 1239) for freeways:
 Stopping out of traffic
 Emergency services & incidence response
 Maintenance operations

The high-speed nature of freeways reinforces the importance of providing these functions. For
instance, the high speed differential between a stopped vehicle and adjacent traffic leads to a
greater need to get stopped traffic out of the travelled way. Also, the limited access nature of
freeways generally means that there are fewer access points to provide potential refuge.

When a range is given for shoulder width, use the mode/function/performance approach
described in Chapter 1106 and “design up” to choose a width within the range. See Chapter
1239 for additional considerations for choosing a shoulder width.

1232.04 Other Elements

See the following chapters for guidance related to these other common geometric cross section
elements:
 Side slopes, medians & curbs Chapter 1239
 Lateral clearance Chapter 1239
 Cross slope and superelevation Chapter 1250

1232.05 Design Flexibility

There are always locations that warrant special consideration. Existing freeways may have
constraints (right-of-way or environmental considerations, for example) that make the cost of
widening outweigh the benefits. The optimum solution may include widths different than those
shown.

If this is the case for your project, and you choose widths different than shown in the Design
Manual, formulate alternative solutions that consider the tradeoffs associated with various lane
and shoulder widths and document the decision in a Design Analysis. Where appropriate,
include documentation of your consultation with the project advisory team (see Chapter 1100)
in the Design Analysis. When compiling the Design Analysis, consider recent design resources
that explore options, performance, functions, and mitigation associated with various lane and
shoulder dimensions. One source is FHWA HOP-16-060 “Use of Narrow Lanes and Narrow
Shoulders on Freeways.” Another source is NCHRP 15-47, “Developing an Improved Highway
Geometric Design Process”.

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1232.06 References

1232.06(1) Design Guidance

Highway Runoff Manual, M 31-16, WSDOT

Local Agency Guidelines (LAG), M 36-63, WSDOT

Plans Preparation Manual, M 22-31, WSDOT

Standard Plans for Road, Bridge, and Municipal Construction, M 21-01, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction, M 41-10, WSDOT

1232.06(2) Supporting Information

Understanding Flexibility in Transportation Design – Washington, WA-RD 638.1, Washington
State Department of Transportation, 2005
 www.wsdot.wa.gov/research/reports/fullreports/638.1.pdf

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition
 www.transportation.org/Pages/Default.aspx

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 Geometric Cross Section –
Chapter 1238 Streetside and Parking
1238.01 General
1238.02 Parking
1238.03 Streetside
1238.04 Retrofit Options
1238.05 References

1238.01 General
The geometric cross section of a roadway is composed of different elements. The cross sections
shown in Chapter 1231 include parking and various zones within the streetside (see Exhibit
1238-1). This chapter provides information on parking and streetside elements. The need to
provide a particular element is dependent on the context and modal needs for a given section of
roadway.

1238.02 Parking
On-street parking is typically provided in urban and rural town center areas, but is not
necessarily required. On-street parking can help visually narrow the street in places to assist in
conveying the surrounding context for the segment. Refer to municipal codes regarding parking
requirements, and coordinate with the municipality involved. Also, if on-street parking will be
either delineated or metered, the ADA has requirements on the number and configuration of
parking stalls for people with disabilities. Consult with a regional ADA subject matter expert.

On-street parking can be either parallel or angled. However, angled parking on any state route
requires approval from the State Traffic Engineer.

Submit a request for angled parking approval through the region Traffic Office. Include an
engineering study documenting that the parking will not unduly reduce safety and that the
roadway is of sufficient width that parking will not interfere with the normal movement of
traffic.

Provide for vehicle overhang within the furnishing zone for all angled parking locations. Consider
back-in angled parking if bike lanes are present to improve conflict management through
increased visibility.

When designing parking locations for freight loading areas, it is important to consider both the
delivery vehicle size and how the vehicle loading/unloading is done. Consult with business
owners and freight carriers to locate and configure the freight loading areas.

Width considerations: Cross sections in the Design Manual generally show a range for parallel
parking of 7 to 9 feet. AASHTO defines a passenger car width as 7 feet. Additional width can
allow a buffer for car doors opening, a buffer for bike riders, or a stall that can accommodate
delivery trucks.

Work with stakeholders to determine the appropriate width to provide within the site-specific
constraints.

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1238.03 Streetside
The area behind the curb is referred to as the “streetside” and is described in terms of “zones.”
Information about each zone is provided below. Note, local agency partners may have policy
containing additional streetside zones to consider.

WSDOT uses the following terminology to describe the zones found within the streetside:
 Frontage Zone
 Pedestrian Zone
 Furnishing Zone
Exhibit 1238-01 Zones within the Streetside

The streetside is the interface between pedestrians and land use. A robust streetside can serve
as both a pedestrian thoroughfare and a destination, which is desirable in many urban core and
main street contexts to help promote economic vitality. The streetside can also reinforce the
target speed. The pedestrian zone will always be present in streetside design, but other zones
are optional and dependent on the modal and contextual needs and desired balance of
performance needs within the available right of way.

The Americans with Disabilities Act (ADA) requires specific design element dimensions for
streetside elements, depending on the configuration. In general, the pedestrian zone and
frontage zone will always be part of the pedestrian circulation path (PCP). The furnishing zone
may or may not be part of the PCP, depending on how it is designed. See Chapter 1510 for
detailed accessibility criteria and design guidance for pedestrian facilities.

1238.03(1) Frontage Zone

The frontage zone serves the retail functions, and is the portion of the sidewalk that provides
the connection to the building. The frontage zone includes the building, the façade, and the
space immediately adjacent to the building. The primary purpose is access to retail space

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without interfering with the required pedestrian access route (PAR) within the pedestrian zone.
The frontage zone may also provide space for sidewalk cafes, temporary retail product displays,
advertisements, and/or outdoor seating for customers. If there is no retail or residential access
need adjacent to the streetside, a frontage zone may not be necessary.

Width considerations: Cross sections in Design Manual generally show a range for the frontage
zone width of 2 to 12 feet.

Narrow, 2-ft frontage zones provide for a clear area where protruding objects from the building
can be located without compromising the pedestrian access route. Two feet also provides an
offset from the building and minimal space for entering/exiting the building.

Wider frontage zones, such as 12-ft can provide width for a variety of possible elements, such as
sidewalk café dining with tables and chairs along the building. If a frontage zone is to be
provided, work with stakeholders to determine the appropriate width to provide within the site-
specific constraints.

1238.03(2) Pedestrian Zone

The pedestrian zone is the space available to accommodate pedestrian travel that will:
 Create interconnectivity between different land uses
 Provide for the transfer between modes
 Separate pedestrians from vehicular traffic
 Support walking as a transportation mode

The pedestrian zone is located within the Pedestrian Circulation Path and includes the
Pedestrian Access Route (PAR) needed to meet ADA accessibility criteria (see Chapter 1510). The
pedestrian zone may be considerably wider than the PAR.

A generous pedestrian zone width promotes the mobility and accessibility typically anticipated
within some urban and suburban contexts.

Consider wider pedestrian zones when the following are present:

 Transit facilities and passenger shelters
 Access routes to businesses
 School walking routes
 Other high pedestrian activity generators

Width considerations: The minimum pedestrian zone width of 5 feet corresponds to WSDOT’s
minimum sidewalk width (see Chapter 1510). Other considerations when choosing a pedestrian
zone width include:
 In many downtown environments, the focus is on multimodal transportation and, in
particular, pedestrian accessibility and use. Wider streetside zones promote a greater
sense of safety, and can provide a comfortable and inviting area that can attract
pedestrians.

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 In urban/downtown environments where store fronts/businesses are located, a larger

width is recommended. Consider providing wider sidewalks to increase pedestrian
comfort levels and to promote walking.
 In places with higher pedestrian volumes, a 10 foot width allows for pedestrians
walking side-by-side or in groups to pass others comfortably without changing
directions or walking speed.
 A 10 foot width provides sufficient width for a wheelchair user to turn around and to
pass another wheelchair user (5 foot width is typically adequate to perform these
maneuvers).
 The minimum sidewalk width of 5 feet is appropriate in low pedestrian volume areas,
such as where there are few stores abutting the street or in residential neighborhoods.

Work with stakeholders to determine the appropriate width to provide within site-specific
constraints.

1238.03(3) Furnishing Zone

The furnishing zone is the key buffer component between the active pedestrian walking area
(pedestrian zone) and the roadway. The furnishing zone provides area for multiple functions.
The furnishing zone is not located within the Pedestrian Access Route (PAR). However, a PAR
connection is required to many features that may be found in this zone (such as street furniture,
parking meters, transit shelters, and transit boarding areas.)

The Furnishing zone:

 Promotes environmental and aesthetic features that improve people’s experience
 Contains street trees, street furniture, benches, planter boxes, and artwork
 Provides for the travel of the various modes through modal segregation or clearance to
obstructions
 Discourages crossings at less desirable locations along the facility with use of buffers.

Traffic signs and signal cabinets; utility poles; fire hydrants; parking meters; transit boarding,
queuing, and shelters; and bike racks are also generally found within the furnishing zone.

Involve the local agency, regional Landscape Architect, and safety professionals to determine
optimal vegetation types.

Other width accommodations for on-street parking may be needed for vehicle overhang or
entering/exiting movements when parking is present.

Coordinate with region Program Management to understand potential funding limitations for
furnishing zone features described within this section. Partnerships or grants may be necessary
to complete all desired features within the furnishing zone.

Width considerations: A width of 2 feet provides the minimum width to accommodate utilities
and street furniture. Greater widths accommodate a larger variety of possible features within
the furnishing zone. Other considerations when choosing a furnishing zone width include:

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 An 8-foot width or greater generally provides sufficient space to accommodate a bus

transit stop (loading/unloading) and a transit shelter (see Chapter 1430 and work with
the transit provider to determine needed space.)
 In commercial areas, a minimum furnishing zone width of 4 feet is recommended.
 In areas where snow accumulation can occur, the furnishing zone can provide snow
storage space that does not decrease the width of the pedestrian zone.
 When higher vehicle speeds are present, providing a larger width to act as a buffer
between vehicles and pedestrians is desirable.

If a furnishing zone is to be provided, work with stakeholders to determine the appropriate

width to provide in order to accommodate the expected features within the site-specific
constraints.

1238.04 Retrofit Options

Retrofit options refer to the application of lower-cost treatments that utilize paint and other
delineation devices rather than hardscape features. Retrofit applications are particularly useful
when:
 Construction will occur in phases over a timeline greater than one year between
phases where overlapping areas of work occur, or when elements or features are
funded by a partnering agency.
 Implementing speed management treatments (see Chapter 1103) that, after evaluating
their effectiveness, may need to be reconfigured.
 Funding is unable to adequately accomplish the identified scope of work.

Applied retrofit options may require additional maintenance over long-duration applications.
Coordination with maintenance jurisdictions as described in Chapter 301 is critical to evaluating
the potential maintenance outcomes for retrofit options being considered. The retrofit options
discussed within the following subsections are more likely to be applied in urban context
settings. Note that cities over 25,000 population will have the responsibility of maintaining any
retrofit delineation, and it will be critical to ensure they have the resources to maintain striped
retrofit features.

The following subsections describe several common applications of retrofit options.

1238.04(1) Relocate Curbs

Changes to the geometric cross section may involve relocating the existing curb. While installing
a new curb may be preferred, there are a number of additional considerations (like stormwater
conveyance) that make relocating curb lines cost-prohibitive. However, there are multiple
retrofit solutions that can provide effective accommodation including, but not limited to:
 Striping combined with MUTCD-approved channelization devices.
 Curb extensions offset from the original curb. Depending on the use of the new curbed
section, retrofit designs may include slotted grates tying the existing curb and new curb
together while maintaining the original stormwater conveyance system.
 Colorized pavement to delineate a change of use.

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Geometric Cross Section – Streetside and Parking Chapter 1238

Use retrofit features as a low-cost solution to create wider sidewalk areas, curb extensions,
bicycle parking areas, parklet areas, and/or green street low-impact development solutions.

Note that retrofits like this must

comply with the accessibility criteria for pedestrian facilities in Chapter 1510.

“Moving the Curb” Photo courtesy of NACTO.org

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Chapter 1238 Geometric Cross Section – Streetside and Parking

1238.04(2) Parklets and Plazas

Parklets and plazas reuse existing right of way in urban and rural town centers, providing public
space to support the economic vitality and social livability performance of a particular context.
As geometric cross sections are reconfigured, spaces may become available at intersections or
for repurposing a parking area into either plazas or parklets. The primary intent of presenting
these treatments is for low-speed roadways or main streets with volumes at or below 20,000
ADT. However, there are many potential constraints external to the engineering design that may
need resolution before application. Consult with Real Estate Services to discuss the specific
property management-related concerns and any potential lease and/or economic payment
considerations proportionally appropriate for utilization of the highway space in this manner, as
further detailed in RCW 47.24.020(15).

A parklet specifically uses the area usually used for

parking to create a space for pedestrians. A common
application provides seating accommodations to
support local restaurants and shops.

Parklet designs will vary depending on local

jurisdiction regulations, but they typically include
railing and/or planter boxes to provide a separation
of uses between people and traffic. Parklet design
should not cover catch basins or other features that
may require frequent maintenance. Parklets interact
with motorized vehicle traffic best when placed on
tangent alignments.

Plazas can reuse right of way to define a relatively

large common public space. Plazas are typically
associated with a central gathering location for
special events, and will likely have limited application
on Washington state highways.

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Geometric Cross Section – Streetside and Parking Chapter 1238

1238.05 References

1238.05(1) Design Guidance

Highway Runoff Manual, M 31-16, WSDOT

Local Agency Guidelines (LAG), M 36-63, WSDOT

Plans Preparation Manual, M 22-31, WSDOT

Standard Plans for Road, Bridge, and Municipal Construction, M 21-01, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction, M 41-10, WSDOT

1238.05(2) Supporting Information

Understanding Flexibility in Transportation Design – Washington, WA-RD 638.1, Washington
State Department of Transportation, 2005
 www.wsdot.wa.gov/research/reports/fullreports/638.1.pdf

Urban Street Design Guide, National Association of City Transportation Officials, New York, NY,
2013
 www.nacto.org

Urban Street Stormwater Guide, National Association of City Transportation Officials, New York,
NY, 2017
 www.nacto.org

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition
 www.transportation.org/Pages/Default.aspx

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 Geometric Cross Section – Shoulders,
Chapter 1239 Side Slopes, Curbs, and Medians
1239.01 Introduction
1239.02 Shoulders
1239.03 Fill Sections, Cut Sections, and Ditch Sections
1239.04 Roadway Sections in Rock Cuts
1239.05 Curbs
1239.06 Lateral Clearance to Curb and Barrier
1239.07 Medians and Outer Separations
1239.08 Documentation

1239.01 Introduction
This chapter provides information on geometric cross section components that are common to
many facility types. Cross section elements include: shoulders, medians and outer separations,
side slopes, and curbing.

1239.02 Shoulders
Shoulders are typically used on high, or intermediate speed limited and non-limited access
facilities, some rural contexts, as well as intermediate-speed locations that do not have
streetsides (curb-sections) (see Chapter 1238). Intermediate-speed locations in suburban and
urban contexts that utilize streetsides do not need to include a shoulder unless determined to
be necessary by shoulder function, (where intended for bicyclists for example) or safety
performance analysis, hydraulic analysis or engineering judgment.

Shoulders provide space to escape potential collisions or reduce their severity. They also provide
a sense of openness, contributing to driver ease at higher speeds. Shoulders also convey
drainage away from the traveled way as determined by hydraulic analysis.

1239.02(1) Shoulder Width

Shoulder width ranges for highways are shown in Exhibit 1239-1. Use the
mode/function/performance approach (Chapter 1106) to choose a dimension from the range
given.

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

Exhibit 1239-1 Shoulder Widths for Highways

Shoulder Width [1] [2]

Posted Speed Highway Type Inside
Outside
(median)
High speed Freeway (including Interstate) See Chapter 1232
(≥50mph) Other highway 4’ – 10’ 4’ – 10’
Intermediate speed
All 4’ – 8’ 4’ – 8’[3]
(40 & 45 mph)
Low speed
All 0’ – 8’ [2] 2’ – 8’[3]
(≤35mph)

Notes:
[1] Bus use only shoulder width range is 12-ft to 14-ft.
[2] If curb or barrier present, see Exhibit 1239-9.
[3] Intermediate-speed and low-speed locations in urban and suburban contexts utilizing
streetsides do not need to include a shoulder unless necessary for safety performance,
hydraulic performance or engineering judgment. See Exhibit 1231-5, Exhibit 1231-6 (A & B),
Exhibit 1231-7 (B & C), and Section 1239.02.
1239.02(1)(a) Shoulder Width Considerations

Exhibit 1239-2 lists considerations for choosing an appropriate shoulder width from the range
given. The considerations listed help one to understand the modal needs and function
associated with different shoulder widths.

Contact the Area Maintenance Superintendent to determine the shoulder width appropriate for
maintenance operations. In some cases, a continuous width is not necessary; instead, the focus
is placing the shoulder width near assets with high-frequency maintenance needs. Compare the
added cost of the wider shoulders to the added benefits to maintenance operations as well as
other benefits that may be derived (see Chapter 301).

The usable shoulder is the width necessary to provide the desired function (see Exhibit 1239-2).
Usable shoulder width is less than the constructed shoulder width when vertical features (such
as traffic barrier or walls) are at the edge of the shoulder. This is because drivers tend to shy
away from the vertical feature. For widening for traffic barrier, see Chapter 1610. For
requirements for lateral clearance to barrier or curb, see 1239.06.

Shoulder widths greater than 10 feet may encourage use as a travel lane. Therefore, use
shoulders wider than 10 feet only to meet one of the listed functions (see Exhibit 1239-2).

When walls are placed adjacent to shoulders, see Chapters 730 and 740 for barrier guidance.

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

Exhibit 1239-2 Shoulder Function & Modal Accommodation Width Considerations

Shoulder Function Shoulder Width Guidance [7]

Stopping out of the traffic lanes 8 ft – 12 ft [1]
Minimum lateral clearance to curb or barrier See 1239.06
Part time shoulder use. (Requires a Design Analysis) 11 ft to 14 ft [2] See Section 1232.03
Bicycle use 4 ft of usable shoulder [3]
Pedestrian use See Section 1510.06
Off-tracking of large accommodated vehicles See Section 1310.02(5)
U-turn turnouts Varies – See Chapter 1310
Maintenance operations (Consult Area Superintendent) Varies [4] [5]
Law enforcement, emergency services & incident response 8 ft [5]
Transit stops See Chapter 1430
Slow-vehicle turnouts See Section 1270.04
Slow-vehicle shoulder driving See Section 1270.05
Ramp meter storage (Requires a Design Analysis) 8 – 12 ft [1]
HOV ramp meter bypass (Requires a Design Analysis) 10 – 14 ft [6]
Ferry holding 8 ft – 12 ft [1]
For use as a lane during reconstruction of the through lanes 8 ft – 12 ft [1]
Structural support of pavement 2 ft
Improve sight distance in cut sections See Chapter 1260
Notes:
[1] 10 foot minimum recommended for freight or transit vehicles.
[2] For bus use only shoulder, the range is 12 ft to 14 ft and the selected width should be
determined with transit provider. For lateral clearance requirements see 1239.06.
[3] Minimum usable shoulder function width for bicycles. Additional width may be needed when
combined with shoulder rumble strips, curb, or barrier (see Chapter 1600 and the Standard
Plans). For guidance, see Chapter 1520 for accommodating bicycles.
[4] 10 foot usable width to park a maintenance truck out of the through lane; 14 foot width for
equipment with outriggers to work out of traffic (consult Area Maintenance Superintendent).
[5] For additional information, see Chapters 1370, 1410 and 1720.
[6] Determine width with transit provider, and see 1239.06 for lateral clearance requirements.
[7] Presence of barrier or curb may require additional width. Use auto turn studies for non-tangent
alignments.

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

Exhibit 1239-3 Shoulder Details

See Exhibit
1239-4 for
ditch details

See Exhibit
1239-4 for
ditch details

See Exhibit
1239-4 for
ditch details

*AP = Angle point in the subgrade

Notes:
 The top three drawings illustrate angle points in subgrade to drain stormwater away from the
roadbed.
 For applicable numbered notes, see next page.

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

Exhibit 1239-3 Shoulder Details (continued)

Notes:
[1] Shoulder cross slopes are normally the same as the cross slopes for adjacent lanes. (For examples
and additional information for locations where it may be desirable to have a shoulder cross slope
different than the adjacent lane, see Chapter 1250).
[2] Provide widening and slope rounding outside the usable shoulder when foreslope is steeper than
4H:1V.
[3] For shoulder width guidance, see Exhibit 1239-1.
[4] For additional requirements for sidewalks, see Chapter 1510.
[5] See 1239.05 for curb design guidance.
[6] Provide paved shoulders wherever extruded curb is placed. (See the Standard Plans for additional
details and dimensions.)
[7] Consider using the same application of slope rounding on all ramps and crossroads, as well as the
main roadway. Use end rounding on the crossroad just beyond the ramp terminals and at a similar
location where only a grade separation is involved.
[8] When widening beyond the edge of usable shoulder for curb or barrier, additional widening for
slope rounding may be omitted.
[9] For widening guidelines for guardrail and concrete barrier, see Chapter 1610.

General:
On divided multilane highways, see Exhibits 1239-12a through 1239-12c for additional details for
median shoulders.

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

1239.03 Fill Sections, Cut Sections, and Ditch Sections

The design for side slopes can affect shoulder design, clear zone requirements, and whether or
not traffic barrier is warranted.

There are three basic roadway sections for side slopes.

Fill sections – Roadway sections where the height of the roadway is higher than the existing
natural ground.

Ditch sections - Roadway sections where the height of the roadway is higher than the existing
natural ground but not as high as the needed roadside ditch so that after the needed ditch is
installed there is a foreslope into the ditch and a back slope out of the ditch up to where it
catches the natural ground.

Cut sections - Roadway sections where the height of the roadway is lower than the existing
ground. This typically produces a foreslope into the ditch and a back slope out of the ditch up to
where it catches the natural ground.

When designing side slopes, attempt to fit the slope selected for any fill section, ditch section, or
cut section into the existing terrain to give a smooth transitional blend from the construction to
the existing landscape when practicable. Flatter slopes are desirable, especially with higher
posted speeds and when the associated cost does not significantly exceed other design options.
Fill side slopes not steeper than 4H:1V, with smooth transitions where the slope changes, will
provide a reasonable opportunity to recover control of an errant vehicle. Fill side slopes
designed to 4H:1V or flatter are preferred. Provide widening and slope rounding outside the
usable shoulder when the foreslope is steeper than 4H:1V (see Exhibit 1239-3). Do not disturb
existing stable cut slopes just to meet the 4H:1V foreslope preference.

Fill-slopes steeper than 4H:1V but flatter than 3H:1V are considered traversable, but not
recoverable. When providing a slope that meets these characteristics, placement of a clear area
extending from the toe of the slope to the outside edge of the design clear zone is needed for an
errant vehicle runout and stop (see Chapter 1600 for design clear zone guidance). Consult with
Region Maintenance to determine if mowing is contemplated. When providing fill-slopes
steeper than 3H:1V, it is a best practice to document the reason for the decision in the design
documentation package. When mowing is contemplated, provide slopes not steeper than
3H:1V.

Where unusual geological features or soil conditions exist, treatment of the slopes depends
upon results of a review of the location by the Region Materials Engineer.

See Section 1600.03(1) for when to use traffic barrier to mitigate a side slope. Unmitigated
critical slopes will require a Design Analysis. The steepest slope allowed is determined by the
Region Materials Engineer based on soil conditions. If more material is needed to build the
roadway, consider obtaining it by flattening cut slopes uniformly on one or both sides of the
highway. Consult the Region Materials Engineer to determine what percentage of the excavated
material will likely be suitable for fill material. Where considering wasting excess material on an
existing fill side slope, consult the Region Materials Engineer to verify that the subgrade will
support the additional material.

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

Provide for drainage from the roadway surface and drainage in ditches (see Chapter 800). For
drainage ditches, see Section 1239.03(1). At locations where vegetated filter areas or detention
facilities will be established to improve highway runoff water quality, provide appropriate slope,
space, and soil conditions for that purpose. (See the Highway Runoff Manual for design criteria
and additional guidance.)

It is desirable to plant and establish low-growing vegetation on non-paved roadsides. This type
of treatment relies on the placement of a lift of compost or topsoil over base course material in
the roadway cross section. Consult with the area Maintenance Superintendent and the region or
HQ Landscape Architect to determine the appropriate configuration of the roadway cross
section and soil and plant specifications. This kind of treatment would not be done where
barrier is installed along the roadway as the lift of compost or topsoil is not a suitable barrier
foundation.

Flatten freeway section median cross-over foreslopes to 10H:1V (See Section 1370.03). Flatten
crossroad and road approach foreslopes not steeper than 6H:1V on other highways. Grade
crossroad and road approach foreslopes flatter than 6H:1V where feasible. Provide smooth
transitions between the main line foreslopes and the crossroad or road approach foreslopes.
Move the crossroad or road approach drainage as far away from the main line as feasible. This
can locate the pipe outside the Design Clear Zone and reduce the length of pipe.

Provide slope treatment as shown in the Standard Plans (Slope treatment) at the top of roadway
cut slopes except for cuts in solid rock. Unless Class B slope treatment is called for, Class A slope
treatment is used. Call for Class B slope treatment where space is limited, such as where right of
way is restricted.

1239.03(1) Drainage Ditches

Exhibit 1239-4 provides general information regarding drainage ditch design. The preferred
cross section of a ditch is trapezoidal as shown. A ‘V’ bottom ditch can be used where
constraints, such as limited right of way or sensitive areas, preclude a trapezoidal ditch. Ensure
hydraulic design requirements are still met. ‘V’ bottom ditches need to be deeper than a
trapezoidal ditch to convey the same amount of water and a ‘V’ bottom ditch requires more
maintenance to keep its shape than a trapezoidal ditch. Consult the Region Hydraulics Engineer
for ditch depth and bottom of ditch width. ‘V’ bottom drainage ditches can have the effect of
eroding the slope toes and in cases where the foundation soil is weak, could result in a side
slope failure. As a general rule, the weaker the foundation and the higher the side slopes, the
more important it is to use a trapezoidal ditch instead if a ‘V’ bottom ditch. Consult the Region
Materials Engineer for the proper ditch type, location and appropriate foreslope and backslope.

When topographic restrictions exist, consider an enclosed drainage system with appropriate
inlets and outlets.

Maintenance operations are also facilitated by adequate width between the toe of the slope
and an adjacent drainage ditch. Where this type of facility is anticipated, provide sufficient right
of way for access to the facility and place the drainage ditch as close to the right of way line as
feasible.

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

Exhibit 1239-4 Drainage Ditch Details

Notes:
 Freeboard is the vertical distance from the bottom of base course to the 10-year
storm water surface (see the Hydraulics Manual for more information.)
 Coordinate ditch depth and bottom of ditch width with region Hydraulics.
 Coordinate foreslope and backslope and ditch location with region Materials
Engineer.
 See other sections of this chapter for shoulder and side slope details.

1239.03(2) Bridge End Slopes

Bridge end slopes are determined by several factors, including context, fill height, depth of cut,
soil stability, and horizontal and vertical alignment. Coordinate bridge end slope treatment with
the HQ Bridge and Structures Office (see Chapter 720). Whenever possible, design to avoid
creating environments that might be desirable to the homeless, both for their safety and the
safety of maintenance staff.

Early in the bridge plan development, determine preliminary bridge geometrics, end slope rates,
and toe of slope treatments. Exhibit 1239-5a provides guidelines for use of slope rates and toe
of slope treatments for overcrossings. Exhibit 1239-5b shows toe of slope treatments to be used
on the various toe conditions.

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

Exhibit 1239-5a Bridge End Slopes

Bridge End Slope

Toe of Slope End Slope Rate Lower Roadway Treatment [1]
Condition Rate
Posted speed
Height Rate of lower Treatment
End Piers on Fill roadway
≤ 35 ft 1¾H:1V > 50 mph Rounding
> 35 ft 2H:1V [2] ≤ 50 mph No rounding
End Piers No rounding, toe at centerline
Match lower roadway slope [3] [4]
in Cut of the lower roadway ditch.
Lower Roadway No rounding, toe at centerline
Match lower roadway slope [3] [4]
in Cut of the lower roadway ditch.
When the cut depth is > 5 ft
When the cut depth is > 5 ft
and length is > 100 ft, no
and length is > 100 ft, match [4]
rounding, toe at centerline of
Ends in Partial cut slope of the lower roadway
the lower roadway ditch
Cut and Fill
When the cut depth is ≤ 5 ft or When the cut depth is ≤ 5 ft or
the length is ≤ 100 ft, it is the length is ≤ 100 ft, it is [4]
designer’s choice designer’s choice

Notes:
[1] See Exhibit 1239-5b.
[2] Slope may be 1¾H:1V in special cases.
[3] In interchange areas, continuity may require variations.
[4] See 1239.03.

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

Exhibit 1239-5b Bridge End Slope Details

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

1239.04 Roadway Sections in Rock Cuts

There are two basic design treatments applicable to rock excavation. Typical sections for rock
cuts, illustrated in Exhibits 1239-6 and 1239-7, are guides for the design and construction of
roadways through rock cuts. Design A applies to most rock cuts. Design B is a talus slope
treatment. Changes in slope or fallout area are recommended when justified. Base the selection
of the appropriate sections on an engineering study and the recommendations of the region
Materials Engineer and region Landscape Architect. Obtain concurrence from the Headquarters
(HQ) Materials Lab.

1239.04(1) Design A
This design is shown in stage development to aid the designer in selecting an appropriate
section for site conditions in regard to backslope, probable rockfall, hardness of rock, and so on.

The following guidelines apply to the various stages shown in Exhibit 1239-6:
 Stage 1 is used where the anticipated quantity of rockfall is small, adequate fallout
width can be provided, and the rock slope is ½H:1V or steeper. Controlled blasting is
recommended in conjunction with Stage 1 construction.
 Stage 2 is used when a “rocks in the road” problem exists or is anticipated. Consider
it on flat slopes where rocks are apt to roll rather than fall.
 Stage 3 represents the full implementation of all protection and safety measures
applicable to rock control. Use it when extreme rockfall conditions exist.

Show Stage 3 as the ultimate stage for future construction in the Plans, Specifications, and
Estimates (PS&E) if there is any possibility that it will be needed.

The use of Stage 2 or Stage 3 alternatives (concrete barrier) is based on the designer’s analysis
of the particular site. Considerations include maintenance; size and amount of rockfall; probable
velocities; availability of materials; ditch capacity; adjacent traffic volumes; distance from
traveled lane; and impact severity. Incorporate removable sections in the barrier at
approximately 200-foot intervals. Provide appropriate terminal treatment (see Chapter 1610).

Occasionally, the existing ground above the top of the cut is on a slope approximating the design
cut slope. The height (H) is to include the existing slope or that portion that can logically be
considered part of the cut. Select cut slopes for a project that provide stability for the existing
material.

Benches may be used to increase slope stability; however, the use of benches may alter the
design given in Exhibit 1239-6.

The necessity for benches, as well as their width and vertical spacing, is established after an
evaluation of slope stability. Make benches at least 20 feet wide. Provide access for
maintenance equipment to the lowest bench and to the higher benches if feasible. Greater
traffic benefits in the form of added safety, increased horizontal sight distance on curves, and
other desirable attributes may be realized from widening a cut rather than benching.

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 Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

Exhibit 1239-6 Roadway Sections in Rock Cuts: Design A

Rock Slope H (ft) W (ft)

20 – 30 12
Near
30 – 60 15
Vertical
> 60 20
20 – 30 12
0.25H:1V 30 – 60 15
through
0.50H:1V 60 – 100 20
>100 25

Notes:
[1] For widening for guardrail and concrete barrier, see Chapter 1610.

General:
 Treat cut heights less than 20 feet as a normal roadway unless otherwise determined by the Region
Materials Engineer.
 Stage 2 and Stage 3 Alternates may be used when site conditions dictate.
 Fence may be used in conjunction with the Stage 3 Alternate. (See Chapter 1600 for clear zone
guidelines.)

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

1239.04(2) Design B
A talus slope treatment is shown in 1239-7. The rock protection fence is placed at any one of the
three positions shown, but not in more than one position at a particular location. Consult with
the RME for the placement of the rock protection fence in talus slope areas.

 Fence position a is used when the cliff generates boulders less than 0.25 yd3 in size
and the length of the slope is greater than 350 feet.
 Fence position b is the preferred location for most applications.

 Fence position c is used when the cliff generates boulders greater than 0.25 yd3 in
size regardless of the length of the slope. On short slopes, this may require placing
the fence less than 100 feet from the base of the cliff.
 Use of gabions may be considered instead of the rock protection shown in fence
position a. Because gabion treatment is considered similar to a wall, provide
appropriate face and end protection (see Chapters 730 and 1610).

Use of the alternate shoulder barrier is based on the designer’s analysis of the particular site.
Considerations similar to those given for Design A alternatives apply.

Evaluate the need for rock protection treatments other than those described above for cut
slopes that have relatively uniform spalling surfaces (consult with the RME).

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

Exhibit 1239-7 Roadway Sections in Rock Cuts: Design B

Notes:

[1] For widening for guardrail and concrete barrier, see Chapter 1610.

General:
 Ordinarily, place fence within a zone of 100 feet to 200 feet maximum from base of
cliff, measured along the slope.
 Rock protection fence may be used in conjunction with the Shoulder Barrier
Alternate when site conditions dictate.

1239.04(3) Stepped Slopes

Stepped slopes are a construction method intended to promote early establishment of
vegetative cover on the slopes. They consist of a series of small horizontal steps or terraces on
the face of the cut slope. Soil conditions dictate the feasibility and necessity of stepped slopes.
They are to be considered on the recommendation of the RME (see Chapter 610). Consult the
region landscape personnel for appropriate design and vegetative materials to be used. Use
Exhibit 1239-8 for stepped slope design.

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Exhibit 1239-8 Stepped Slope Design

Notes:
[1] Staked slope line: Maximum slope 1H:1V.
[2] Step rise: Height variable 1 foot to 2 feet.
[3] Step tread: Width = staked slope ratio x step rise.
[4] Step termini: Width ½-step tread width.
[5] Slope rounding.
[6] Overburden area: Variable slope ratio.

1239.05 Curbs
Curbs are designated as either vertical or mountable. Vertical curbs have a face slope 1H:3V or
steeper. Mountable curbs have a sloping face that is more readily traversed.

Curbs can also be classified as mountable. Mountable curbs are sloped curb with a height of 6
inches or less; 4 inches or less is recommended to reduce underside vehicle damage if driven
over. When the face slope is steeper than 1H:1V, the height of a mountable curb is limited to 4
inches or less.

1239.05(1) Vertical Curb Uses

(a) Use vertical curbs with a height of 6 inches or more:
 To inhibit vehicles from leaving the roadway on low-speed roadways.
 To discourage vehicles from leaving low - and intermediate-speed roadways.

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

 For walkway and pedestrian refuge separations.

 For raised islands on which a traffic signal or traffic signal hardware is located.
 For expediting transfer times for transit partners on low- speed roadways in urban and
suburban contexts (verify curb height needed with transit provider).

(b) Consider vertical curbs with a height of 6 inches or more:

 To inhibit midblock left turns.
 For divisional and channelizing islands.
 For landscaped islands.
 For stormwater conveyance

1239.05(2) Mountable Curb Uses

(a) Provide mountable curbs where a curb is needed but vertical curb is not suitable.

(b) Provide mountable curb where a curb is needed, but accommodation for specific design
user(s) makes mountability necessary.

(c) Use mountable curbs in roundabouts. See Chapter 1320 and Standard Plan F-10.18-01.

1239.05(3) Curb Use Based On Speed

In general, curbs are not recommended on high-speed facilities. Avoid using curbs if the same
objective can be attained with pavement markings. However, 4-inch-high mountable curbs may
be used on high-speed facilities to control drainage or for access control. Locate mountable curb
no closer to the traveled way than the outer edge of the shoulder. Provide sloping end
treatments where the curb is introduced and terminated. 6-inch-high mountable curbs may be
considered on high-speed urban and suburban contexts where streetside zones are provided or
where traffic movements are to be restricted. Provide justification for the use of vertical curb
when applied to high-speed facilities.

Intermediate speed facilities may use vertical curbs; however, consider mountable curbs for
intermediate target speeds. Consider use of 12-inch to 18-inch vertical curb when analysis
demonstrates a need to reduce concerns of lane departure into oncoming lane on intermediate-
speed facilities. All curb types are appropriate for low-speed facilities.

1239.05(4) Curb Used For Drainage

Where curbing is provided to direct drainage, provide a design that collects the surface water at
the curb and drains it without ponding in the traveled way or flowing across the roadway.

In some areas, curb may be needed to control runoff water until ground cover is attained to
control erosion. Document the plan to remove the curb when the ground cover becomes
adequate. A best practice is to arrange for curb removal with region maintenance staff as part of
the future maintenance plans (see Maintenance Owner’s Manual guidance in Chapter 301).

When curb is used in conjunction with guardrail, see Chapter 1610 for guidance. For existing
curb, particularly on high-speed facilities, evaluate the continued need for the curb. Remove
curbing that is no longer needed.

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

1239.05(5) Curb Use Considerations

Curbs are not considered adequate to redirect an errant vehicle.

When an overlay will reduce the height of a curb, evaluate grinding (or replacing the curb) to
maintain curb height if needed for pavement performance design and/or drainage performance.
(See 1250.02(2) for shoulder cross slope considerations.) To maintain or restore curb height,
consider lowering the existing pavement level and improving cross slope by grinding before an
asphalt overlay or as determined by the pavement design. The cross slope of the shoulder may
be steepened to maximize curb height and minimize other related impacts. Note that grinding
can cause issues with meeting ADA criteria at curb ramps for counter slope and crosswalk
running slope. See Chapter 1510 for more information.

Curbs can hamper snow-removal operations. In areas of heavy snowfall, ask the Area
Maintenance Superintendent to review and concur with the use of curbing.

For curbs at traffic islands, see Chapter 1310. For curbs at roundabouts, see Chapter 1320 and
Standard Plan F-10.18-01.

1239.06 Lateral Clearance to Curb and Barrier

Lateral clearance to curb or barrier is the perpendicular distance from edge of traveled way to
the face of a curb or a traffic barrier (guardrail, concrete barrier, etc.). Lateral clearance includes
the shoulder width. The minimum lateral clearance to the face of a curb or barrier is shown in
Exhibit 1239-9. See also Chapter 1310 for intersections including clearance to curb at traffic
islands.

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

Exhibit 1239-9 Minimum Lateral Clearance to Barrier and Curb

Posted Speed Curb - Median [1] [2] Curb - Right [1] [2] Barrier

High Speed 4 ft; curb not recommended

4 ft; curb not recommended [4]
(≥50mph) [4]
Intermediate
4 ft; curb not recommended
Speed 4 ft; curb not recommended [4]
[4] 4 ft
(40 & 45mph)
Low Speed
2 ft Preferred [3] 2 ft Preferred [3]
(≤35mph)
Ramps [5] [6] 4 ft

Notes:
[1] For HOV lanes on arterials streets, see Section 1410.06(4)(d)
[2] Measured from the edge of traveled way to the face of curb.
[3] On low speed urban roadways (35 mph or less), maintaining shoulder width is desirable;
however, with justification, curb (mountable or vertical) may be placed at the edge of
traveled way.
[4] With justification, mountable curb may be placed at the edge of traveled way for access
management in urban areas. Adding mountable curb reduces lane and/or shoulder width
and may require additional documentation.
[5] Raised median for two-way ramps (see 1360.03(5).)
[6] 2 ft min. for ramp design where speeds are ≤35mph (usually near the ramp terminal
intersection) and 4 ft. min. where design speeds are > 35mph.

1239.07 Medians and Outer Separations

Medians are either restrictive or nonrestrictive. Restrictive medians physically limit motor
vehicle encroachment, using raised curb, median barrier, fixed delineators, vegetative strips, or
vegetative depressions. Nonrestrictive medians limit motor vehicle encroachment legally, and
use pavement markings to define locations where turns are permissible. The main functions of
an outer separation are to separate the main roadway from a frontage road or service lane, or
to provide modal segregation. Consider medians or outer separations to optimize the desired
performance objective, such as safety, throughput operations, pedestrian mobility needs, etc.

Provide a median or outer separation to:

 Separate traffic lanes such as HOT lanes, HOV lanes, bike lanes, etc.
 Separate divided highways with differing alignments.
 Separate opposing traffic to reduce the risk of head-on collisions.
 Manage speed.
 Provide a refuge area for emergency parking.
 Allow for future widening of a planned phase.

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

 Separate collector-distributor lanes, frontage roads, weigh sites, or rest areas.

 Accommodate drainage facilities.
 Accommodate bridge piers at undercrossings.
 Provide vehicle storage space for crossing and left-turn movements at intersections.
 Accommodate headlight glare screens, including planted or natural foliage.
 Provide recovery areas for errant or disabled vehicles.
 Provide a pedestrian refuge area at crossing locations.
 Provide storage space for snow and water away from traffic lanes.
 Separate modes for increased safety, comfort, and ease of operations.
 Control access.
 Provide enforcement areas.

The width of a median is measured from edge of traveled way to edge of traveled way and
includes shoulders. Median widths can vary greatly based on the functional use of the median,
the functional use of the shoulders, target speed, and context. Guidance for median and
shoulder widths depending on their function and context is given in:

 Exhibit 1239-10 (high & intermediate speed medians),

 Exhibit 1239-11 (low & intermediate speed medians), and Exhibit

 Exhibit 1239-2 (shoulders).

1239.07(1) Median Design: High and Intermediate Speed

Exhibit 1239-10 lists width considerations for median functions common on high-speed facilities.
Depending on the context and performance needs, this guidance may also apply to intermediate
speed facilities as well.

When the horizontal and vertical alignments of the two roadways of a divided highway are
independent of one another, determine median side slopes in conformance with 1239.03 and
Chapters 1600 and 1610. Independent horizontal and vertical alignment, rather than parallel
alignment, can allow for reduced grading or cut sections.

Considerable latitude in grading treatment is intended on wide, variable-width medians,

provided the minimum performance needs are met or exceeded. Unnecessary clearing,
grubbing, and grading are undesirable within wide medians. Use selective thinning and limited
reshaping of the natural ground when feasible. For median clear zone criteria see Chapter 1600,
and for slopes between the face of traffic barriers and the traveled way see Chapter 1610.

In areas where land is expensive, make an economic comparison of wide medians to narrow
medians with barrier. Consider right of way, construction, maintenance, and safety
performance. The widths of medians need not be uniform. Make the transition between median
widths as long as practical. (See Chapter 1210 for minimum taper lengths.)

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

When using concrete barriers in depressed medians or on the insides of curves, provide for
surface drainage on both sides of the barrier. The transverse notches in the base of precast
concrete barrier are not intended to be used as a drainage feature, but rather as pick-up points
when placing the sections.

At locations where the median will be used to allow vehicles to make a U-turn, consider
increasing the width to meet the needs of the selected design vehicles making the U-turn. (For
information on U-turn locations, see Chapter 1310.) Document the selected design vehicle and
provide alternate route information for vehicles not serviced by the U-turn.

Where feasible, widen medians at intersections on rural divided multilane highways. Provide
sufficient width to store vehicles crossing the expressway or entering the expressway with a left
turn.

When the median is to be landscaped, or where fixed objects are to be placed in the median,
see Chapter 1600 for traffic barrier and clear zone guidance. When the median will transition for
use as a left-turn lane, see Chapter 1310 for left-turn lane design considerations.

Exhibit 1239-10 Median Functions and Guidance: High and Intermediate Speeds

Median Functional Use Width Guidance

Separating opposing traffic Varies[1] and see Chapters 1600 and 1610
Separating alignments Varies See 1239.03 and Chapters 1600 and 1610 [2]
Recovery/Refuge areas for errant vehicles See 1239.03 and Chapter 1600
Median signing and illumination – 6 ft [1] or as recommended for signing and illumination
Undivided highways and ramps design
Storage space for snow Consult Region Maintenance
See Chapters 1370 and 1410, and consult with
Enforcement areas
Washington State Patrol
Vehicle storage space for crossing at See Chapter 1310, and consult with region traffic
intersections engineer
Median U-turn or Median crossover See Chapters 1310 and 1370
Outer separation for frontage or collector- 12 ft min plus shoulders [1] See Exhibit 1360-15a and
distributer roads Chapters 1360, 1600 and 1610
Varies; see Chapter 1420 and discuss with Transit
Transit use
Agency [3]
6 ft minimum, excluding curb width
Pedestrian refuge for crossing locations
(see Chapter 1510)

Notes:
[1] Conduct a safety performance analysis and include potential countermeasures identified to obtain
the desired safety performance. Consult with maintenance; additional width may be appropriate

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

for unconstrained right of way locations, maintenance functions, or for divided highways on
independent alignments.
[2] An economic comparison of wide medians to narrow medians with barrier is recommended.
[3] For planning and scoping purposes, 32 ft can be the assumed minimum for two-way transit
operations or 22 ft for one-way transit operations.

1239.07(2) Median Design: Low and Intermediate Speeds

Exhibit 1239-11 provides design guidance for medians within low-speed transportation contexts.
Depending on the context and performance needs, this guidance may also apply to intermediate
speed facilities as well. In low-speed urban and suburban contexts, see Chapter 1600 for Design
Clear Zone requirements.

A common form of restrictive median on urban managed access highways is the raised median.
For more information on traffic volume thresholds for restrictive medians on managed access
highways, see Chapter 540.

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

Exhibit 1239-11 Median Functions and Guidance: Low and Intermediate Speeds

Median Functional Use Width Guidance

Access Control – Restrictive Width of raised median feature [1] [2]

Access Control – Non-restrictive 1 ft minimum [3] (see Chapter 540)

6 ft minimum, excluding curb width
Pedestrian refuge for crossing locations
(see Section 1510.11)
Speed management and/or aesthetic design –
Varies [2] [4] (see Chapter 1103)
Vegetated
Drainage or treatment facilities Varies [5]

Bicyclist buffer treatment 2 ft – 3 ft (see Chapter 1520)

Transit connection Varies [6] (see Chapters 1238 and 1430)

Outer separation for frontage or collector- distributer 12 ft min. plus shoulders [4] [7] [8]
roads See Exhibit 1360-15a, Design B

Notes:
[1] The width of a raised median can be minimized by using a dual-faced cement concrete traffic
curb, a precast traffic curb, or an extruded curb.
[2] Consider width necessary for lateral clearance.
[3] 2 ft minimum if adjacent lane widths are less than 11 ft.
[4] Consult Region Landscape Architect; width will depend on type of plantings. Over-excavation may
be necessary to prepare soil for the selected plantings to ensure mature heights are obtained.
[5] Consult Hydraulic Report for width necessary for drainage or treatment facilities.
[6] Consult with the transit provider. If a transit shelter is planned, a minimum 5 ft clear area
measured from the edge of shelter roofing to face of curb width, is necessary for pedestrians to
move to and around the shelter and for lift extension (see Chapter 1430).
[7] Consider width needed for plantings or street furniture to create the appropriate pedestrian zone
segregation and environment.
[8] See also Chapter 1510

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

Exhibit 1239-12a Divided Highway Median Sections

Note:
For applicable notes, see Exhibit 1239-12c.

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

Exhibit 1239-12b Divided Highway Median Sections

Note:
For applicable notes, see Exhibit 1239-12c.

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Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians Chapter 1239

Exhibit 1239-12c Divided Highway Median Sections

[11]
Edge of Edge of
[7] [7] traveled way
traveled way

[12] [12]

Design F: Raised Median[13]

Notes:
[1] For guidance on median widths, see Exhibits 1239-10 and -11
[2] Consider vertical clearances, drainage, and aesthetics when locating the pivot point.
[3] Generally, slope pavement away from the median. When barrier is present and the
roadway is in a superelevation, size the shoulder so that standing water is not in the travel
lane. Where appropriate, a crowned roadway section may be used in conjunction with the
depressed median.
[4] Design B may be used uniformly on both tangents and horizontal curves. Use Alternate
Design 1 or Alternate Design 2 when the "rollover" between the shoulder and the inside
lane on the high side of a superelevated curve exceeds 8%. Provide suitable transitions at
each end of the curve for the various conditions encountered in applying the alternate to
the basic median design.
[5] Method of drainage pickup to be determined by the designer.
[6] Median shoulders normally slope in the same direction and rate as the adjacent through
lane. See 1250.02(2) for examples and additional information for locations where it may be
desirable to have a shoulder cross slope different than the adjacent lane.
[7] For guidance on shoulder widths, see 1239.02.
[8] Future lane width of a planned phase.
[9] Widen and round foreslopes steeper than 4H:1V as shown in Exhibit 1239-3. See Chapter
1600 for barrier recommendations.
[10] Designs C, D, and E are rural high-speed median designs. See Exhibit 1239-10 for
recommended median widths.
[11] Raised medians may be paved or landscaped. For clear zone and barrier guidelines when
fixed objects or trees are in the median, see Chapter 1600.
[12] Lane and shoulders normally slope away from raised medians. When they slope toward the
median, provide for drainage.
[13] See 1239.05 and 1239.06 for curb design guidance.

1239.08 Documentation
Refer to Chapter 300 for design documentation requirements and approving authorities.

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Chapter 1239 Geometric Cross Section – Shoulders, Side Slopes, Curbs, and Medians

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Chapter 1240 Turning Roadways
1240.01 General
1240.02 Turning Roadway Widths
1240.03 Documentation
1240.04 References

1240.01 General
The roadway on a curve may need to be widened to make the operating conditions comparable
to those on tangents. There are two main reasons to do this. One is the off-tracking of vehicles
such as trucks and buses. The other is the increased difficulty drivers have in keeping their
vehicles in the center of the lane. Apply turning roadway widths only when there is a need to
optimize the operational or safety performance of a particular segment of roadway with larger
volumes of trucks or when trucks are the identified modal priority. The application of turning
roadway width is not applicable on managed access low-speed roadways or managed access
intermediate-speed highways in suburban or urban contexts.

For additional information, see the following chapters:

Chapter Subject
1230 Cross section design element widths
1250 Superelevation
1360 Lane and shoulder widths for ramps

1240.02 Turning Roadway Widths

1240.02(1) Two-Lane Two-Way Roadways
Exhibit 1240-1a shows the traveled way width (W) for two-lane two-way roadways. For values
of radius (R) between those given, interpolate W and round up to the next foot.

Minimum traveled way width (W), based on the delta angle of the curve (shown in Exhibit 1240-
1b), may be used. Document the reasons for using the minimum width. Round W to the nearest
foot.

Widths given in Exhibits 1240-1a and 1b are for facilities with 12-foot lanes. When 11-foot lanes
are selected, width (W) may be reduced by 2 feet.

1240.02(2) Two-Lane One-Way Roadways

Exhibit 1240-2a shows the traveled way width (W) for two-lane one-way turning roadways,
including two-lane ramps and four-lane highways. For values of radius (R) between those given,
interpolate W and round up to the next foot. Treat each direction of travel on four-lane facilities
as a one-way roadway.

Minimum traveled way width (W), based on the delta angle of the curve (shown in Exhibit 1240-
2b), may be used. Document the reasons for using the minimum width. Round W to the nearest
foot.

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Turning Roadways Chapter 1240

Widths given in Exhibits 1240-2a and 2b are for facilities with 12-foot lanes. When 11-foot lanes
are selected, width (W) may be reduced by 2 feet.

To keep widths to a minimum, the traveled way widths for Exhibits 1240-2a and 2b were
calculated using the WB-40 design vehicle. When volumes are high for trucks larger than the
WB-40 and other traffic, consider using the widths from Exhibits 1240-1a and 1b.

1240.02(3) One-Lane Roadways

Exhibit 1240-3a shows the traveled way width (W) for one-lane turning roadways. For values
of R between those given, interpolate W and round up to the next foot. Exhibit 1240-3a applies
to one-lane ramps only when the largest vehicles present demonstrate a safety or operational
need based on frequency of use and shoulder pavement depths, and when turn simulation
software shows that the total roadway width cannot accommodate the turning movement
within the structural pavement section.

Minimum width (W), based on the delta angle of the curve for one-lane roadways, may be used.
Exhibit 1240-3b gives W using the radius to the outer edge of the traveled way. Exhibit 1240-3c
gives W using the radius on the inner edge of the traveled way. Document the reasons for using
the minimum width. Round W to the nearest foot.

Build shoulder pavements at full depth for one-lane roadways. To keep widths to a minimum,
traveled way widths were calculated using the WB-40 design vehicle, which may force larger
vehicles to encroach on the shoulders. This also helps to maintain the integrity of the roadway
structure during partial roadway closures.

1240.02(4) Other Roadways

For roadways where the traveled way is more than two lanes in any direction:
• For each lane in addition to two, additional width in excess of the selected lane width
dimension (see Chapters 1230 and 1106) is not needed.
• For three-lane ramps with HOV lanes, see Chapter 1410.

1240.02(5) Total Roadway Width

Shoulder widths for the highway or ramp are added to the traveled way width to determine the
total roadway width.

Small amounts of widening add to the cost with little added benefit. When the traveled way
width for turning roadways results in widening less than 0.5 foot per lane, or a total widening
of less than 2 feet on existing roadways that are to remain in place, it may be disregarded.

When widening the traveled way:

• Widening may be constructed on the inside of the traveled way or divided equally
between the inside and outside. Do not construct widening only on the outside of
a curve.
• Place final marked lane lines, and any longitudinal joints, at equal spacing between
the edges of the widened traveled way.

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Chapter 1240 Turning Roadways

• Provide widening throughout the curve length.

• For widening on the inside, make transitions on a tangent where possible.
• For widening on the outside, develop the widening by extending the tangent.
This avoids the appearance of a reverse curve that a taper would create.
• For widening of 6 feet or less, use a 1:25 taper. For widths greater than 6 feet,
use a 1:15 taper.

1240.03 Documentation
Refer to Chapter 300 for design documentation requirements.

1240.04 References
1240.04(1) Design Guidance
Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications),
M 41-10, WSDOT

1240.04(2) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition

WSDOT Design Manual M 22-01.12 Page 1240-3

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Turning Roadways Chapter 1240

Exhibit 1240-1a Traveled Way Width for Two-Lane Two-Way Turning Roadways

Radius on Centerline Design Traveled

of Traveled Way, R (ft) Way Width, W (ft)[1]
3,000 to tangent 24
2,999 25
2,000 26
1,000 27
800 28
600 29
500 30
400 31
350 32
300 33
250 35
200 37
150 41

Note:
[1] Width (W) is based on:
 WB-67 design vehicle
 3-ft clearance per lane (12-ft lanes)

When 11-ft lanes are selected, width may be reduced by 2 ft.

Centerline

Edge of shoulder

W
Edge of
traveled way
R

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Chapter 1240 Turning Roadways

Exhibit 1240-1b Traveled Way Width for Two-Lane Two-Way Turning Roadways: Based on the Delta Angle

45

ft

ft
00

75
1
R= R=150 ft

R=
40
Traveled Way Width, W (ft)

R=200 ft

35 R=250 ft

R=300 ft
R=350 ft
R=400 ft
30 R=500 ft
R=600 ft
R=800 ft
R=1,000 ft

R=2,000 ft
25
0 30 60 90

Delta Angle of Curve (degrees)

Note:
Width (W) is based on:
 WB-67 design vehicle
 3-ft clearance per lane (12-ft lanes)

When 11-ft lanes are selected, width may be reduced by 2 ft.

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November 2015
Turning Roadways Chapter 1240

Exhibit 1240-2a Traveled Way Width for Two-Lane One-Way Turning Roadway

Radius on Centerline of Design Traveled Way

Traveled Way, R (ft) Width, W (ft)[1]

3,000 to tangent 24
1,000 to 2,999 25
999 26
600 26
500 27
400 27
300 28
250 29
200 29
150 31
100 34

Note:
[1] Width (W) is based on:
 WB-40 design vehicle
 3-ft clearance per lane (12-ft lanes)

When 11-ft lanes are selected, width may be reduced by 2 ft.

Centerline

Edge of shoulder

W
Edge of
traveled way
R

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Chapter 1240 Turning Roadways

Exhibit 1240-2b Traveled Way Width for Two-Lane One-Way Turning Roadways: Based on the Delta Angle

35
ft R=100 ft
7 5
R=
Traveled Way Width, W (ft)

R=150 ft

30
R=200 ft

R=250 ft

R=300 ft

R=400 ft
R=600 ft

R=1,000 ft
25
0 30 60 90

Delta Angle of Curve (degrees)

Note:
Width (W) is based on:
 WB-40 design vehicle
 3-ft clearance per lane (12-ft lanes)

When 11-ft lanes are selected, width may be reduced by 2 ft.

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November 2015
Turning Roadways Chapter 1240

Exhibit 1240-3a Traveled Way Width for One-Lane Turning Roadways

Design Traveled Way Width, W (ft)

Radius, R (ft)
Radius on Outside Radius on Inside
Edge of Traveled Way Edge of Traveled Way

7,500 to tangent 13[1] 13[1]

1,600 14 14
300 15 15
250 16 16
200 17 17
150 17 17
100 19 18
75 21 19
50 26 22

Note:
[1] On tangents, the minimum lane width is selected based on Chapters 1230 and 1106.
Width (W) is based on:
 WB-40 design vehicle
 4-ft clearance

Edge of shoulder

W
Edge of
R on outside
traveled way
R on inside

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Chapter 1240 Turning Roadways

Exhibit 1240-3b Traveled Way Width for One-Lane Turning Roadways: Based on the Delta Angle, Radius on
Outside Edge of Traveled Way

22

21 ft
5 0 R=75 ft
R=
Traveled Way Width, W (ft)

20

R=100 ft
19

18

R=150 ft
17
R=200 ft

16 R=250 ft

15

14
0 10 20 30 40 50 60 70 80 90 100

Delta Angle of Curve (degrees)

Note:
All radii are to the outside edge of traveled way.
Width (W) is based on:
 WB-40 design vehicle
 4-ft clearance

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November 2015
Turning Roadways Chapter 1240

Exhibit 1240-3c Traveled Way Width for One-Lane Turning Roadways: Based on the Delta Angle, Radius on
Inside Edge of Traveled Way

22
R=50 ft

21
Traveled Way Width, W (ft)

20
R=75 ft

19
R=100 ft

18

R=150 ft
17
R=200 ft

16 R=250 ft

15

14
0 10 20 30 40 50 60 70 80 90 100
Delta Angle of Curve (degrees)

Note:
All radii are to the inside edge of traveled way.
Width (W) is based on:
 WB-40 design vehicle
 4-ft clearance

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Chapter 1250 Cross Slope and Superelevation
1250.01 General
1250.02 Roadway Cross Slope
1250.03 Superelevation Rate Selection
1250.04 Existing Curves
1250.05 Turning Movements at Intersections
1250.06 Runoff for Highway Curves
1250.07 Runoff for Ramp Curves
1250.08 Documentation
1250.09 References

1250.01 General
Use this chapter to design roadway cross slopes and superelevation. Cross slopes function to
drain water away from the roadway and 2% is a commonly used slope rate. To maintain the
design speed, highway and ramp curves are usually superelevated to overcome part of the
centrifugal force that acts on a vehicle.

1250.02 Roadway Cross Slope

1250.02(1) Lanes
The cross slope on tangents and curves is a main element in roadway design. The cross slope or
crown on tangent sections and large radius curves is complicated by the following two
contradicting controls:
 Reasonably steep cross slopes aid in water runoff and minimize ponding as a result of
pavement imperfections and unequal settlement.
 Steeper cross slopes are noticeable in steering, increase the tendency for vehicles to
drift to the low side of the roadway, and increase the susceptibility of vehicles to slide
to the side on icy or wet pavements.
A 2% cross slope is normally used for tangents and large-radius curves on high and intermediate
pavement types, although cross slopes may vary from the target 2%.
The algebraic difference in cross slopes is an operational factor that can affect vehicles making a
lane change across a grade-break during a passing maneuver on a two-lane two-way roadway.
Its influence increases when increased traffic volumes decrease the number and size of available
passing opportunities.
On ramps with metering, consider how cross slopes can impact driver comfort within the queue.
Additionally, larger cross slopes may present concerns about maintaining vehicle lateral position
within the queue lane, depending on weather and resulting pavement conditions.
A somewhat steeper cross slope may be needed to facilitate recommended drainage design,
even though this might be less desirable from an operational point of view. In such areas,
consider not exceeding design cross slopes of 2.5% with an algebraic difference of 5%.

For a two-lane two-way roadway, provide an algebraic difference to meet the appropriate
conditions stated above except when drainage design recommends otherwise.

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Cross Slope and Superelevation Chapter 1250

1250.02(2) Shoulders
Shoulder cross slopes are normally the same as the cross slopes for adjacent lanes. With
justification, shoulder slopes may be increased to 6%. On the high side of a roadway with a
plane section, such as a turning roadway in superelevation, the shoulder may slope in the
opposite direction from the adjacent lane. The maximum difference in slopes between the lane
and the shoulder is 8%. Locations where it may be desirable to have a shoulder slope different
than the adjacent lane are:
 Where curbing is used.
 Where shoulder surface is bituminous, gravel, or crushed rock.
 Where overlays are planned and it is desirable to maintain the grade at the edge of the
shoulder.
 On divided highways with depressed medians where it is desirable to drain the runoff
into the median.
 On the high side of the superelevation on curves where it is desirable to drain
stormwater or meltwater away from the roadway.
 At intersections where pedestrian signal accommodations are provided within the
shoulder

Where extruded curb is used, see the Standard Plans for placement (see Chapter 1239 for
information on curbs). Widening is also normally provided where traffic barrier is installed (see
Chapter 1610 and the Standard Plans).

On ramps with metering, where the shoulder is or could be utilized for queuing, consider how
the shoulder cross slope can impact driver comfort within the queue. Additionally, larger
shoulder cross slopes may present concerns of maintaining vehicle lateral position within the
queue lane, depending on weather and resulting pavement conditions.

The remainder of this chapter provides information to design superelevation.

1250.03 Superelevation Rate Selection

The maximum superelevation rate allowed is 10%.

Depending on design speed, construct large-radius curves with a normal crown section. The
minimum radii for normal crown sections are shown in Exhibit 1250-1. Superelevate curves
with smaller radii as follows:
 Exhibit 1250-4a (emax=10%) is desirable for all open highways, ramps, and long-term
detours, especially when associated with a main line detour.
 Exhibit 1250-4b (emax =8%) may be used for freeways in urban design areas and areas
where the emax =6% rate is allowed but emax =8% is preferred.
 Exhibit 1250-4c (emax =6%) may be used—with justification—for non-freeway
highways in urban design areas, in mountainous areas, and for short-term detours,
which are generally implemented and removed in one construction season.
 Exhibit 1250-5 may be used for turning roadways at intersections, urban managed
access highways with a design speed of 40 mph or less, and—with justification—ramps
in urban areas with a design speed of 40 mph or less.

Page 1250-2 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1250 Cross Slope and Superelevation

When selecting superelevation for a curve, consider the existing curves on the corridor. To
maintain route continuity and driver expectance on open highways, select the chart (see
Exhibits 1250-4a, 4b, or 4c) that best matches the superelevation on the existing curves.

In locations that experience regular accumulations of snow and ice, limit superelevation from
the selected chart to 6% or less. In these areas, provide justification for superelevation rates
greater than 6%. Vehicles moving at slow speeds or stopped on curves with supers greater than
6% tend to slide inward on the radius (downslope).

Round the selected superelevation rate to the nearest full percent.

Exhibit 1250-1 Minimum Radius for Normal Crown Section

Minimum Radius for Normal

Design Speed (mph)
Crown Section (ft)
15 945
20 1,680
25 2,430
30 3,325
35 4,360
40 5,545
45 6,860
50 8,315
55 9,920
60 11,675
65 13,130
70 14,675
75 16,325
80 18,065

1250.04 Existing Curves

Evaluate the superelevation on an existing curve to determine its adequacy. Use the equation in
Exhibit 1250-2 to determine the minimum radius for a given superelevation and design speed.
Exhibit 1250-2 Minimum Radius for Existing Curves

6.68V 2
R
e f

Where:
R = The minimum allowable radius of the curve (ft)
V = Design speed (mph)
e = Superelevation rate (%)
f = Side friction factor from Exhibit 1250-3

WSDOT Design Manual M 22-01.14 Page 1250-3

July 2017
Cross Slope and Superelevation Chapter 1250

Address superelevation when the existing radius is less than the minimum radius calculated
using the equation or when the maximum speed determined by a ball banking analysis is less
than the design speed. When modifying the superelevation of an existing curve, provide
superelevation as given in 1250.02.

Exhibit 1250-3 Side Friction Factor

Design Speed (mph) Side Friction Factor (f)

15 32
20 27
25 23
30 20
35 18
40 16
45 15
50 14
55 13
60 12
65 11
70 10
75 9
80 8

1250.05 Turning Movements at Intersections

Curves associated with the turning movements at intersections are superelevated using the
rates for low-speed urban roadway curves. Use superelevation rates as high as practicable,
consistent with curve length and climatic conditions. Exhibit 1250-5 shows the minimum
superelevation for the given design speed and radius. When using high superelevation rates on
short curves, provide smooth transitions with merging ramps or roadways.

1250.06 Runoff for Highway Curves

Provide transitions for all superelevated highway curves as specified in Exhibits 1250-6a through
6e. Which transition to use depends on the location of the pivot point, the direction of the
curve, and the roadway cross slope. The length of the runoff is based on a maximum allowable
difference between the grade at the pivot point and the grade at the outer edge of traveled way
for one 12-foot lane.

Pay close attention to the profile of the edge of traveled way created by the superelevation
runoff; do not let it appear distorted. The combination of superelevation transition and grade
may result in a hump and/or dip in the profile of the edge of traveled way. When this happens,
the transition may be lengthened to eliminate the hump and/or dip. If the hump and/or dip
cannot be eliminated this way, pay special attention to drainage in the low areas to prevent
ponding. Locate the pivot point at the centerline of the roadway to help minimize humps and
dips at the edge of the traveled lane and reduce the superelevation runoff length.

Page 1250-4 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1250 Cross Slope and Superelevation

When reverse curves are necessary, provide sufficient tangent length for complete
superelevation runoff for both curves—that is, from full superelevation of the first curve, to
level to full superelevation of the second curve. If tangent length is longer than this, but not
sufficient to provide full super transitions—that is, from full superelevation of the first curve, to
normal crown to full superelevation of the second curve—increase the superelevation runoff
lengths until they abut. This provides one continuous transition, without a normal crown
section, similar to Designs C2 and D2 in Exhibits 1250-6c and 6d, except that full super will be
attained rather than the normal pavement slope as shown.

Superelevation runoff on structures is permissible but not desirable. Whenever practicable,

strive for full super or normal crown slopes on structures.

1250.07 Runoff for Ramp Curves

Superelevation runoff for ramps use the same maximum relative slopes as the specific design
speeds used for highway curves. Multilane ramps have a width similar to the width for highway
lanes; therefore, Exhibits 1250-6a through 6e are used to determine the superelevation runoff
for ramps. Superelevation transition lengths (LT) for single-lane ramps are given in Exhibits 1250-
7a and 7b. Additional runoff length for turning roadway widening is not required.

1250.08 Documentation
Refer to Chapter 300 for design documentation requirements.

1250.09 References

1250.09(1) Design Guidance

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications),
M 41-10, WSDOT

1250.09(2) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition

WSDOT Design Manual M 22-01.14 Page 1250-5

July 2017
Cross Slope and Superelevation Chapter 1250

Exhibit 1250-4a Superelevation Rates (10% Max)

10

8
Superelevation (%)

6
20 m

30

40
mp

m
ph

ph
h

4
25
15

m 35 45 m
ph mp ph
mp

h
h

2
0 1,000 2,000 3,000 4,000 5,000 6,000

Radius (ft)

10

8
Superelevation (%)

6
55

65

75
mp

m
ph

ph
h

4
50 60 70 80 m
mp mp mp ph
h h h

2
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000

Radius (ft)

Design Speed (mph) 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Minimum Radius (ft) 40 75 130 205 295 415 545 700 880 1,095 1,345 1,640 1,980 2,380

Page 1250-6 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1250 Cross Slope and Superelevation

Exhibit 1250-4b Superelevation Rates (8% Max)

8
Superelevation (%)

4
45
1 5 mp

25

35

mp
mp

h
m
ph

30
h
h

40
20

m mp
ph h
mp
h

2
0 1,000 2,000 3,000 4,000 5,000 6,000

Radius (ft)

8
Superelevation (%)

4 60 70 80
50

m m mp
ph ph
mp

h
h

55 65 75
mp mp mp
h h h
2
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000

Radius (ft)

Design Speed (mph) 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Minimum Radius (ft) 40 80 135 215 315 450 590 760 965 1,205 1,490 1,820 2,215 2,675

WSDOT Design Manual M 22-01.14 Page 1250-7

July 2017
Cross Slope and Superelevation Chapter 1250

Exhibit 1250-4c Superelevation Rates (6% Max)

6
Superelevation (%)

40
20

30

m
ph
mp

m
ph
h

25
15 m

m 35 45 m
ph mp ph
h
ph

2
0 1,000 2,000 3,000 4,000 5,000

Radius (ft)

6
Superelevation (%)

65 75
55

m mp
ph
m

h
ph

50 60 70
m mp mp 80 m
ph h h ph
2
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000

Radius (ft)

Design Speed (mph) 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Minimum Radius (ft) 40 85 145 235 345 490 645 840 1,065 1,340 1,665 2,050 2,510 3,055

Page 1250-8 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1250 Cross Slope and Superelevation

Exhibit 1250-5 Superelevation Rates for Intersections and Low-Speed Urban Roadways

10

6
Superelevation (%)

2
15 mph

20 mph

2 5 mp h

30 m

35

40
mp

m
ph

ph
h

Flat 0

NC -2
0 100 200 300 400 500 600 700 800

Radius (ft)

NC = Normal crown

WSDOT Design Manual M 22-01.14 Page 1250-9

July 2017
Cross Slope and Superelevation Chapter 1250

Exhibit 1250-6a Superelevation Transitions for Highway Curves

LB=Basic Runoff in Feet for Design Speed*

e
(%) 15 20 25 30 35 40 45 50 55 60 65 70 75 80
mph mph mph mph mph mph mph mph mph mph mph mph mph mph
2 30 30 35 35 40 40 45 50 50 55 55 60 65 70
3 45 50 50 55 60 60 65 70 75 80 85 90 95 105
4 60 65 70 75 75 85 90 95 100 105 110 120 125 135
5 75 80 85 90 95 105 110 120 130 135 140 150 160 170
6 90 95 105 110 115 125 135 145 155 160 170 180 190 205
7 110 115 120 130 135 145 155 170 180 185 195 210 220 240
8 125 130 135 145 155 165 180 190 205 215 225 240 250 275
9 140 145 155 165 175 185 200 215 230 240 250 270 285 310
10 155 160 170 180 195 205 220 240 255 265 280 300 315 345

*Based on one 12-ft lane between the pivot point and the edge of traveled way. When the distance
exceeds 12 ft, use the following equation to obtain LR:

LR = LB(1+0.04167X)

Where:

X = The distance in excess of 12 ft between the pivot point and the farthest edge of traveled way, in ft.

ce
LR  
 e 
Begin (end)
full super
Begin (end) transition

LR
0.7LR 0.3LR
c c ay
LR   LR  
v e le d w A
e e tra
e of urve
Ed g s i d e o f c
ou t
or PT
PC

A CL
wen
100

B B
wcn
100

Pivot point
C Ed g
e of
wcn trave
i n si d le d w
C ro w n e of ay
C ro w n
100 curv
e C
A B C Level Crown Crown slo
pe Full
s upe
Pivot point r

Design A – Pivot Point on Centerline Crown Section

c = Normal crown (%)
e = Superelevation rate (%)
n = Number of lanes between points
w = Width of lane

Page 1250-10 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1250 Cross Slope and Superelevation

Exhibit 1250-6b Superelevation Transitions for Highway Curves

ce

Begin (end) transition

LR  

Begin (end)
 e 

full super
LR
0.7LR 0.3LR
PC or PT
wcn
100 Edge of traveled way
B
wcn
100

outside of curve and

A A
CL pivot point
C

wen
100
B
c c Ed g
LR   LR   eo
e e insi f trave
d e o le d C
f cu w a y
rve
C ro w n
C ro w n Level Crown
A B C C ro w n
slope Full
Pivot point s upe
r

Design B1 – Pivot Point on Edge of Traveled Way:

Outside of Curve Crowned Section

Begin (end)
full super
LR
Begin (end) transition

0.7LR 0.3LR

 c   c  C
LR   LR   ay
 2e   2e 
v e l ed w
tra e
e of curv
or PT

wen
100
Edg tside of B
PC

C ou CL
B
wcn
100

Edge of traveled way inside

A A
wcn of curve and pivot point
100
r
Crown Crown Level C ro w n
slope s upe
C ro w n Full
A B C
Pivot point

Design B2 – Pivot Point on Edge of Traveled Way:

Inside of Curve Crowned Section

c= Normal crown (%)

e= Superelevation rate (%)
n= Number of lanes between points
w= Width of lane

WSDOT Design Manual M 22-01.14 Page 1250-11

July 2017
Cross Slope and Superelevation Chapter 1250

Exhibit 1250-6c Superelevation Transitions for Highway Curves

LR

Begin (end)
full super
0.7LR 0.3LR

or PT
Begin (end)

PC
transition
c
LR  
e
d way
f travele
Edge o ide of curve A
outs
A
CL

wen
wcn

100
100

B B
Pivot point
C
Ed g e o
f tr
C ro w n
slope
C ro w n
slope inside oaveled way C
f curve
A B C Full
Pivot point su p
er

Design C1 – Pivot Point on Centerline Curve

in Direction of Normal Pavement Slope: Plane Section

ce
LR  
 e 
Begin (end) transition

Begin (end)
LR

full super
0.7LR 0.3LR
or PT

c c
PC

LR   LR  
d way
e e f travele
Edge o ide of curve C
outs
A
CL
wcn

wen
100

100

B B
Pivot point
C
Ed g e o
f tr
C ro w n
slope n slope
inside oaveled way A
C ro w f curve
A B C er
su p
Pivot point Full

Design C2 – Pivot Point on Centerline Curve

Opposite to Normal Pavement Slope: Plane Section

c= Normal crown (%)

e= Superelevation rate (%)
n= Number of lanes between points
w= Width of lane

Page 1250-12 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1250 Cross Slope and Superelevation

Exhibit 1250-6d Superelevation Transitions for Highway Curves

LR

0.7LR 0.3LR

Begin (end)
full super
c

Begin (end)

or PT
transition
LR  

PC
e

Edge of traveled way outside

A A
wcn
100

of curve pivot point

B

wen
100
Ed g e o
f tr
C ro w n
slope
C ro w n
slope inside oaveled way B
f curve
A B Full
Pivot point su p
er

Design D1 – Pivot Point on Edge of Traveled Way Curve

in Direction of Normal Pavement Slope: Plane Section

ce
LR  
 e 
Begin (end) transition

Begin (end)
LR

full super
0.7LR 0.3LR
or PT

c c
PC

LR   LR  
d way
e e
d g e o f traveleurve
E of c B
outside
wen
100
Edge of traveled way inside
A A
wcn
100

of curve pivot point

B
r
C ro w n
slope slope s upe
C ro w n Full
A B
Pivot point

Design D2 – Pivot Point on Edge of Traveled Way Curve

Opposite to Normal Pavement Slope: Plane Section

c= Normal crown (%)

e= Superelevation rate (%)
n= Number of lanes between points
w= Width of lane

WSDOT Design Manual M 22-01.14 Page 1250-13

July 2017
Cross Slope and Superelevation Chapter 1250

Exhibit 1250-6e Superelevation Transitions for Highway Curves

Begin (end)

Begin (end)
transition

full super
LR
0.7LR 0.3LR

or PT
PC
 c  y A
LR   c d wa
LR  
tra ve l e e
 3e  e e of curv
Ed g i d e of B
s

wen
t

100
ou
C
C
Edge of traveled way inside
wcn
100

B&D D
of curve pivot point
A
C ro w n Level Crown
C ro w n
C Full
C ro w n
A B D slope sup
e r
Pivot point

Design E1 – Six-Lane With Median, Pivot Point on Edge of Traveled Way:

Inside of Curve Crown Section
Begin (end)
transition

Begin (end) full super

LR
0.7LR 0.3LR

c c or PT
LR   LR  
PC

e e

C
Edge of traveled way outside
wcn
100

B&D D
of curve pivot point
A
C
Ed
ge
wen

C ro w n C ro w n
100

o
C B Level Crow
n ins f tra
D A i d e ve l B
of ed w
Pivot point cu
C ro w n
slope rve ay
A
Full
supe
r

Design E2 – Six-Lane With Median, Pivot Point on Edge of Traveled Way:

Outside of Curve Crown Section

c= Normal crown (%)

e= Superelevation rate (%)
n= Number of lanes between points
w= Width of lane

Page 1250-14 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1250 Cross Slope and Superelevation

Exhibit 1250-7a Superelevation Transitions for Ramp Curves

LT.

Begin (end)

Begin (end)
PC
or PT
transition

full super
 2    2 
0.7L T  0.3L T   0.3 LT  LT  
e2   e  2 

CL WL e
0.02 WL
Pivot point 100
Crown
slope

Full
Pivot point s upe
r

Length of Transition in Feet for Design Speed

e
20 mph 25 mph 30 mph 35 mph 40 mph 45 mph 50 mph 55 mph
(%)
LT LT LT LT LT LT LT LT
3 10 15 15 15 15 15 15 15
4 20 25 25 25 25 30 30 35
5 30 35 35 35 40 45 45 50
6 40 45 45 50 55 55 60 65
7 50 55 55 60 65 70 75 80
8 60 65 70 75 80 85 90 95
9 70 75 80 85 95 100 105 110
10 80 85 90 100 105 115 120 130
Table 1 Pivot Point on Centerline: Curve in Direction of Normal Pavement Slope
LT.
Begin (end)

Begin (end)
transition

full super
 2    2    2 
LT   0.7 LT  LT   0.3 LT  LT  
e2   e  2    e  2 
or PT
PC

CL WL e
0.02 WL
Pivot point 100
Crown
slope Level
r
s upe
Pivot point Full

Length of Transition in Feet for Design Speed

e
20 mph 25 mph 30 mph 35 mph 40 mph 45 mph 50 mph 55 mph
(%)
LT LT LT LT LT LT LT LT
2 40 40 45 50 55 55 60 65
3 50 55 55 60 65 70 75 80
4 60 65 70 75 80 85 90 95
5 70 75 80 85 90 100 105 110
6 80 85 90 95 105 115 120 130
7 90 95 100 110 120 125 135 145
8 100 105 115 120 130 140 150 160
9 110 120 125 135 145 155 165 175
10 120 130 135 145 160 170 180 190
Table 2 Pivot Point on Centerline: Curve in Direction Opposite to Normal Pavement Slope
WL = Width of ramp lane

WSDOT Design Manual M 22-01.14 Page 1250-15

July 2017
Cross Slope and Superelevation Chapter 1250

Exhibit 1250-7b Superelevation Transitions for Ramp Curves

LT.

Begin (end)

Begin (end)
  2 

PC
or PT
 2 

transition

full super
0.7L T  0.3L T   0.3 LT  LT  
e2   e  2 

CL
0.02 WL Pivot point WL e
Crown 100
slope

Pivot point Full

s upe
r

Length of Transition in Feet for Design Speed

e
20 mph 25 mph 30 mph 35 mph 40 mph 45 mph 50 mph 55 mph
(%)
LT LT LT LT LT LT LT LT
3 20 25 25 25 25 30 30 35
4 40 45 45 50 55 55 60 65
5 60 65 70 75 80 85 90 95
6 80 85 90 100 105 115 120 130
7 100 105 115 120 130 140 150 160
8 120 130 135 145 160 170 180 190
9 140 150 160 170 185 195 210 225
10 160 170 180 195 210 225 240 255
Table 3 Pivot Point on Edge of Traveled Way: Curve in Direction of Normal Pavement Slope

LT.
Begin (end)

Begin (end)
transition

full super
 2    2    2 
LT   0.7 LT  LT   0.3 LT  LT  
e2   e  2    e  2 
or PT
PC

WL e
CL 100
0.02 WL Pivot point
Crown r
slope Level s upe
Full
Pivot point

Length of Transition in Feet for Design Speed

e
20 mph 25 mph 30 mph 35 mph 40 mph 45 mph 50 mph 55 mph
(%)
LT LT LT LT LT LT LT LT
2 80 85 90 100 105 115 120 130
3 100 105 115 120 130 140 150 160
4 120 130 135 145 160 170 180 190
5 140 150 160 170 185 195 210 225
6 160 170 180 195 210 225 240 255
7 180 190 205 220 235 255 270 290
8 200 210 225 245 265 280 300 320
9 220 235 250 265 290 310 330 350
10 240 255 270 290 315 340 360 385
Table 4 Pivot Point on Edge of Traveled Way: Curve in Direction Opposite to Normal Pavement Slope
WL = Width of ramp lane

Page 1250-16 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1260 Sight Distance
1260.01 General
1260.02 References
1260.03 Stopping Sight Distance (Eye height – 3.5 ft, Object height – 2.0 ft)
1260.04 Passing Sight Distance (Eye height – 3.5 ft, Object height – 3.5 ft)
1260.05 Decision Sight Distance (Eye height – 3.5 ft, Object height – 2.0 ft)
1260.06 Documentation

1260.01 General
Sight distance allows the driver to assess developing situations and take actions appropriate
for the conditions. Sight distance relies on drivers being aware of and paying attention to their
surroundings and driving appropriately for conditions presented. For the purposes of design,
sight distance is considered in terms of stopping sight distance, passing sight distance, and
decision sight distance.
For additional information, see the following chapters:
Chapter Subject
1250 Sight distance at railroad crossings
1310 Sight distance at intersections at grade
1320 Sight distance at roundabouts
1340 Sight distance at driveways
1515 Sight distance for shared-use paths

1260.02 References
1260.02(1) Design Guidance
Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as
adopted and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices
for streets and highways” (MUTCD)

1260.02(2) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO
Passing Sight Distance Criteria, NCHRP 605

1260.03 Stopping Sight Distance (Eye height – 3.5 ft, Object height – 2.0 ft)
1260.03(1) Design Criteria
Stopping sight distance is provided when the sight distance available to a driver equals or exceeds
the stopping distance for a passenger car traveling at the design speed.
Stopping distance for design is very conservatively calculated, with lower deceleration and
slower perception reaction time than normally expected from the driver. Provide design stopping
sight distance at all points on all highways and on all intersecting roadways, unless a design
deviation is deemed appropriate.

WSDOT Design Manual M 22-01.12 Page 1260-1

November 2015
Sight Distance Chapter 1260

1260.03(1)(a) Stopping Sight Distance

Stopping sight distance is
the sum of two distances:
the distance traveled during
perception and reaction time
and the distance to stop the
vehicle. The perception and
reaction distance used in
design is the distance traveled
in 2.5 seconds at the design
speed.
The design stopping sight
distance is calculated using the
design speed and a constant
deceleration rate of 11.2
feet/second2. For stopping
sight distances on grades less
than 3%, see Exhibit 1260-1;
for grades 3% or greater, see
Exhibit 1260-2.
1260.03(1)(b) Design Stopping Sight Distance
Exhibit 1260-1 gives the design stopping sight distances for grades less than 3%, the minimum
curve length for a 1% grade change to provide the stopping sight distance for a crest (Kc) and
sag (Ks) vertical curve, and the minimum length of vertical curve for the design speed (VCLm).
For stopping sight distances when the grade is 3% or greater, see Exhibit 1260-2.

Design Speed Design Stopping

Kc Ks VCLm (ft)
(mph) Sight Distance (ft)
25 155 12 26 75
30 200 19 37 90
35 250 29 49 105
40 305 44 64 120
45 360 61 79 135
50 425 84 96 150
55 495 114 115 165
60 570 151 136 180
65 645 193 157 195
70 730 247 181 210
75 820 312 206 225
80 910 384 231 240

Design Stopping Sight Distance

Exhibit 1260-1

Page 1260-2 WSDOT Design Manual M 22-01.10

July 2013
Chapter 1260 Sight Distance

1260.03(2) Effects of Grade

The grade of the highway has an effect on the stopping sight distance. The stopping distance is
increased on downgrades and decreased on upgrades. Exhibit 1260-2 gives the stopping sight
distances for grades of 3% and steeper. When evaluating sight distance with a changing grade,
use the grade for which the longest sight distance is needed.
Stopping Sight Distance (ft)
Design Speed
Downgrade Upgrade
(mph)
-3% -6% -9% 3% 6% 9%
25 158 165 173 147 143 140
30 205 215 227 200 184 179
35 257 271 287 237 229 222
40 315 333 354 289 278 269
45 378 400 427 344 331 320
50 446 474 507 405 388 375
55 520 553 593 469 450 433
60 598 638 686 538 515 495
65 682 728 785 612 584 561
70 771 825 891 690 658 631
75 866 927 1,003 772 736 704
80 965 1,035 1,121 859 817 782

Design Stopping Sight Distance on Grades

Exhibit 1260-2

For stopping sight distances on grades between those listed, interpolate between the values
given or use the equation in Exhibit 1260-3.

V2
S  1.47V (2.5) 
  G 
300.347826   
  100 
Where:
S = Stopping sight distance on grade (ft)
V = Design speed (mph)
G = Grade (%)

Stopping Sight Distance on Grades

Exhibit 1260-3

1260.03(3) Crest Vertical Curves

When evaluating an existing roadway, refer to 1260.03(7).
Use Exhibit 1260-4 or the equations in Exhibit 1260-5 to find the minimum crest vertical curve
length to provide stopping sight distance when given the algebraic difference in grades. Exhibit
1260-4 does not show the sight distance greater than the length of curve equation.

WSDOT Design Manual M 22-01.10 Page 1260-3

July 2013
Sight Distance Chapter 1260

When the sight distance is greater than the length of curve and the length of curve is critical,
the S>L equation given in Exhibit 1260-5 shall be used to find the minimum curve length.
When a new crest vertical curve is built or an existing one is rebuilt with grades less than 3%,
provide design stopping sight distance from Exhibit 1260-1. For grades 3% or greater, provide
stopping sight distance from 1260.03(2).

Object height h2=2.0'

Eye height h1=3.5'

The minimum length can also be determined by multiplying the algebraic difference in grades by the
KC value from Exhibit 1260-1 (L=KC*A). Both the exhibit and the equation give approximately the
same length of curve. Neither use the S>L equation.

16
t.

ft.
t.
t.
50 f

ft.
ft.

0f
5f

5
.

25

49
S=155 ft

=200

36
30

=
S=2

=4

,S
S=
S=

,S

14 t.
ph 0f
ph
ph, S

h,

m
ph,

h,

57
mp

55
m

S=
mp

,
50
35 m
2 5 mp h ,

ph
45
Algebraic Difference in Grade, A (%)

30 m

m
40

12
60
.
5 ft
=6 4
10 h, S
mp
65
.
0 ft
= 73
8 h, S
mp
70
.
20 ft
6 p h, S=8
75 m 10 ft
.
p h , S= 9
80 m
4

0
0 500 1000 1500 2000

Length of Vertical Curve, L (ft)

Stopping Sight Distance: Crest Vertical Curves

Exhibit 1260-4

Page 1260-4 WSDOT Design Manual M 22-01.10

July 2013
Chapter 1260 Sight Distance

When S>L

 2158 
2158 L 
L  2S   A 
A S
2
When S<L
AS 2 2158L
L S
2158 A

Where:
L = Length of vertical curve (ft)
S = Sight distance (ft)
A = Algebraic difference in grades (%)

Sight Distance: Crest Vertical Curve

Exhibit 1260-5

1260.03(4) Sag Vertical Curves

When evaluating an existing roadway, refer to 1260.03(7).
Sight distance is not restricted by sag vertical curves during the hours of daylight. Therefore,
headlight sight distance is used for the sight distance design criteria at sag vertical curves.
In some cases, a lesser length may be allowed. For guidance, see Chapter 1220.
Refer to Exhibit 1260-6 or the equations in Exhibit 1260-7 to find the minimum length for
a sag vertical curve to provide the headlight stopping sight distance when given the algebraic
difference in grades. The value for S is shown as the distance between the vehicle and the
point where a 1-degree angle upward of the headlight beam intersects with the roadway.
The sight distance greater than the length of curve equation is not used in Exhibit 1260-6. When
the sight distance is greater than the length of curve and the length of curve is critical, the S>L
equation given in Exhibit 1260-7 shall be used to find the minimum length of curve.
When a new sag vertical curve is built or an existing one is rebuilt with grades less than 3%,
provide design stopping sight distance from Exhibit 1260-1. For grades 3% or greater, provide
stopping sight distance from 1260.03(2).

WSDOT Design Manual M 22-01.10 Page 1260-5

July 2013
Sight Distance Chapter 1260

1°

2.0'

The minimum length can also be determined by multiplying the algebraic difference in grades by the KS
value from Exhibit 1260-1 (L=KS*A). Both the exhibit and equation give approximately the same length
of curve. Neither use the S>L equation.

16
0 ft

ft ft
5 ft

ft
ft

ft
ft

5 95
42
60

70
= 20

05

=4
50
5

S= =5
=3
S=1

=3

,S ,S
2

14 , h
h, S

,S
S=

ph h
,S

p
m mp
ph

m
ph

55
p h,

60
h,

50 5 ft
mp

m
m
mp

= 64
Algebraic Difference in Grade, A (%)

45
25 m

40

h, S
30

12
35

mp
65
0 ft
, S =73 t
h f
10 mp S=820
70 h ,
mp 10 f
t
75 S=9
p h ,
8
80 m

0
0 200 400 600 800 1000 1200 1400 1600 1800 2000

Length of Curve, L (ft)

Stopping Sight Distance for Sag Vertical Curves

Exhibit 1260-6

Page 1260-6 WSDOT Design Manual M 22-01.10

July 2013
Chapter 1260 Sight Distance

When S>L
400  3.5S LA  400
L  2S  S
A 2 A  3.5
When S<L

L
AS 2 3.5L  3.5L2  1600AL
400  3.5S S
2A
Where:
L = Curve length (ft)
A = Algebraic grade difference (%)
S = Sight distance (ft)
Note:
Values for A less than 1.75 are within the 1-degree diverge
of the headlight beam and therefore do not need to be
evaluated for SSD on sag curves.

Sight Distance: Sag Vertical Curve

Exhibit 1260-7

1260.03(5) Horizontal Curves

When evaluating an existing roadway, see 1260.03(7).
Use Exhibit 1260-8 or the equation in Exhibit 1260-9 to check stopping sight distance where
sightline obstructions are on the inside of a curve. A stopping sight distance sightline obstruction
is any roadside object within the
horizontal sightline offset (M)
distance (such as median barrier,
guardrail, bridges, walls, cut
slopes, buildings or wooded
areas), 2.0 feet or greater above
the roadway surface at the
centerline of the lane on the inside
of the curve (h0). Exhibit 1260-8
and the equation in Exhibit 1260-9
are for use when the length of
curve is greater than the sight
distance and the sight restriction is
more than half the sight distance
from the end of the curve. Where
the length of curve is less than the
stopping sight distance or the sight
restriction is near either end of the curve, the desired sight distance may be available with a lesser
M distance. When this occurs, the sight distance can be checked graphically.

WSDOT Design Manual M 22-01.10 Page 1260-7

July 2013
Sight Distance Chapter 1260

Sight distance (S)

A sightline obstruction is any

roadside object within the
horizontal sightline offset (M) M
distance, 2.0 feet or greater
above the roadway surface at Line of
the centerline of the lane on sight
Obstruction or
the inside of the curve. backslope
Radius
Center of lane

60
Lateral Clearance to Obstruction, M (ft)

50
60
65

80
70

75
mp

m
mp

40
m

ph
ph

ph
h, S

,S
h,

,S

,S

=9
S

10
=8
=
=6
=5

73

20

ft
45
70

ft
ft

30
ft
ft

20

10
25 mph, 30 mph, 35 mph, 40 mph, 45 mph, 50 mph, 55 mph,
S=155 ft S=200 ft S=250 ft S=305 ft S=360 ft S=425 ft S=495 ft
0
0 1,000 2,000 3,000 4,000 5,000 6,000

Curve Radius, R (ft)

Horizontal Stopping Sight Distance

Exhibit 1260-8

Page 1260-8 WSDOT Design Manual M 22-01.10

July 2013
Chapter 1260 Sight Distance

When the road grade is less than 3%, provide design stopping sight distance from Exhibit 1260-1.
When the grade is 3% or greater, provide stopping sight distance from 1260.03(2).
Roadside objects with a height (h0) between 2.0 feet and 2.75 feet might not be a stopping sight
distance sightline obstruction. Objects with an h0 between 2.0 feet and 2.75 feet can be checked
graphically to determine whether they are stopping sight distance sightline obstructions.
Where a sightline obstruction exists and site characteristics preclude design modifications to meet
criteria, consult with the region Traffic Engineer and Assistant State Design Engineer for a
determination of appropriate action.

  28.65S  R  1  R  M 
M  R 1  cos  S cos  
  R  28.65   R 
Where:
M = Horizontal sightline offset measured from the centerline of
the inside lane of the curve to the sightline obstruction (ft)
R = Radius of the curve (ft)
S = Sight distance (ft)

Sight Distance: Horizontal Curves

Exhibit 1260-9

1260.03(6) Overlapping Horizontal and Vertical Curves

Vertical curves on a horizontal curve have an effect on which roadside objects are sightline
obstructions. Crest vertical curves make roadside objects more likely to become sightline
obstructions. Sag vertical curves make roadside objects less likely to be sightline obstructions.
Exhibit 1260-10 can be used to determine the sight distance for crest vertical curves on horizontal
curves with:
• Sightline
obstructions
inside the CL of lane
M distance.
• Sightline IMI
obstruction
height (h0)
of 2.0 feet
or less. Roadside sightline
obstruction 2.0' or
Line of
For other less above CL of lane
Sight
locations, the Edge of roadway
sight distance
can be checked
graphically.
hO
h1=3.5' h2=2.0'

WSDOT Design Manual M 22-01.10 Page 1260-9

July 2013
Sight Distance Chapter 1260

The following equation may be used to determine the sight distance for roadside sightline
obstructions inside the horizontal sightline offset (M) distance (see Exhibit 1260-9) with
a height of 2.0 feet or less above the centerline of the lane on the inside of the curve on
overlapping horizontal and crest vertical curves.

S

100L 2h1  h0   2h2  h0  2
A
Where:
L = Length of vertical curve (ft)
S = Sight distance (ft)
A = Algebraic difference in grades (%)
h1 = Eye height (3.5 ft)
h2 = Object height (2.0 ft)
h0 = Height of roadside sightline obstructions above the
centerline of the inside curve lane (2.0 ft or less)
Note:
The above equation cannot be used for sightline obstruction
height (h0) more than 2.0 ft above the centerline of the lane on
the inside of the curve. The available sight distance must be
checked graphically for these sightline obstructions.

Sight Distance: Overlapping Horizontal and Crest Vertical Curves

Exhibit 1260-10

1260.03(7) Existing Stopping Sight Distance

Existing stopping sight distance values from Exhibit 1260-11 may be used at all horizontal
and vertical curves where all of the following are met at the curve:
• There is no identified collision trend.
• The existing vertical and horizontal alignment is retained.
• The existing roadway pavement is not reconstructed.
• The roadway will not be widened, except for minor shoulder widening requiring no work
past the bottom of the ditch.
• The sightline obstruction is existing.
• Roadside improvements to sight distance are within existing right of way.
Crest Vertical Curves – The minimum length of an existing crest vertical curve may be found
using the equations in Exhibit 1260-5 or using the KC values from Exhibit 1260-11.
Sag Vertical Curves – The minimum length of an existing sag vertical curve may be found using
the equations in Exhibit 1260-7 or using the KS values from Exhibit 1260-11. In some cases,
when continuous illumination is provided, a lesser length may be allowed. For guidance, see
Chapter 1220.

Page 1260-10 WSDOT Design Manual M 22-01.10

July 2013
Chapter 1260 Sight Distance

Design Speed Existing Stopping

KC KS
(mph) Sight Distance (ft)
20 115 6 16
25 145 10 23
30 180 15 31
35 220 22 41
40 260 31 52
45 305 43 63
50 350 57 75
55 400 74 89
60 455 96 104
65 495 114 115
70 540 135 127
75 585 159 140
80 630 184 152

Existing Stopping Sight Distance

Exhibit 1260-11

1260.04 Passing Sight Distance (Eye height – 3.5 ft, Object height – 3.5 ft)
1260.04(1) Design Criteria
Minimum passing sight distance Minimum Passing Sight
is the distance (on a two-lane Design Speed (mph)
Distance (ft)
highway) used for a driver
to execute a normal passing 20 400
maneuver based on design 25 450
conditions and design speed. 30 500
The potential for passing maneuver 35 550
conflicts is ultimately determined 40 600
by the judgments of the driver and
the conditions present at the time 45 700
of the maneuver. Exhibit 1260-12 50 800
gives the passing sight distances 55 900
for various design speeds.
60 1000
65 1100
70 1200
75 1300
80 1400

Passing Sight Distance

Exhibit 1260-12

WSDOT Design Manual M 22-01.10 Page 1260-11

July 2013
Sight Distance Chapter 1260

On two-lane two-way highways, provide passing opportunities to meet traffic volume demands.
This can be accomplished with roadway sections that provide passing sight distance or by adding
passing lanes at locations that would provide the greatest benefit to passing (see Chapter 1270).
In the design stage, passing sight distance can be provided by adjusting the alignment either
vertically or horizontally to increase passing opportunities.
These considerations also apply to multilane highways where staged construction includes a
two-lane two-way operation as an initial stage. Whether auxiliary lanes are provided, however,
depends on the time lag proposed between the initial stage and the final stage of construction.

1260.04(2) Passing Sight Distance Vertical Curves

Exhibit 1260-14 gives the length of crest vertical curve used to provide passing sight distance for
two lane highways. The distance from Exhibit 1260-12 and the equations in Exhibit 1260-13 may
also be used to determine the minimum length of vertical curve to meet the passing sight distance
criteria.
Sag vertical curves are not a restriction to passing sight distance.

A
Eye height h1=3.5' Object height h2=3.5'

When S>L
2800 L 1400
L  2S  S 
A 2 A
When S<L
AS 2 2800L
L S
2800 A
Where:
L = Length of vertical curve (ft)
A = Algebraic grade difference (%)
S = Sight distance (ft)

Passing Sight Distance: Crest Vertical Curve Calculations

Exhibit 1260-13

Page 1260-12 WSDOT Design Manual M 22-01.10

July 2013
Chapter 1260 Sight Distance

10

t
t

0f

ft
00 f
9 ft

ft
80
9
25

0
1,0

7
,2
S= 9
6

,4
1,

=1

=1
=

S=
,S

,S
8 t
5f

ph ,
ph
Algebraic Difference in Grade, A (%)

h,
h,

ph
3
m 1,8

mp
mp
25 m

m
45 S=

40
35
,

30
7 ph t
50
m 5f
1, 98
=
,S
6
m ph 5 ft
55 2 ,13
S=
ph, 5 ft
5
60
m
= 2 ,28
h, S
mp 80 f
t
65 =2,4
4 , S
ph
70 m

0
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

Length of Vertical Curve, L (ft)

Passing Sight Distance: Crest Vertical Curves

Exhibit 1260-14

1260.04(3) Passing Sight Distance Horizontal Curves

Passing sight distance can be restricted on the inside of a horizontal curve by sightline
obstructions that are 3.5 feet or more above the roadway surface. Use the distance from
Exhibit 1260-12 and the equation in Exhibit 1260-9 to determine whether the object is close
enough to the roadway to be a restriction to passing sight distance. The equation assumes that
the curve length is greater than the sight distance. Where the curve length is less than the sight
distance, the desired sight distance may be available with a lesser sightline offset (M) distance.

WSDOT Design Manual M 22-01.10 Page 1260-13

July 2013
Sight Distance Chapter 1260

1260.05 Decision Sight Distance (Eye height – 3.5 ft, Object height – 2.0 ft)
Decision sight distance values are greater than stopping sight distance values because they
give the driver an additional margin for error and afford sufficient length to maneuver at the
same or reduced speed rather than to just stop.
Consider decision sight distances (see Exhibit 1260-15) at locations where there is high
likelihood for driver error in information reception, decision making, or control actions.
If site characteristics and budget allow, locate these highway features where decision sight
distance can be provided. If this is not practicable, use suitable traffic control devices and
positive guidance to give advanced warning of the conditions.

Design Speed Decision Sight Distance for Maneuvers (ft)

(mph) A B C D E
30 220 490 450 535 620
35 275 590 525 625 720
40 330 690 600 715 825
45 395 800 675 800 930
50 465 910 750 890 1030
55 535 1030 865 980 1135
60 610 1150 990 1125 1280
65 695 1275 1050 1220 1365
70 780 1410 1105 1275 1445
75 875 1545 1180 1365 1545
80 970 1685 1260 1455 1650

Decision Sight Distance

Exhibit 1260-15

The maneuvers in Exhibit 1260-15 are as follows:

A = Rural stop D = Suburban speed/path/direction change
B = Urban stop E = Urban speed/path/direction change
C = Rural speed/path/direction change
Use the equations in Exhibits 1260-5, 1260-7, and 1260-9 to determine the available decision
sight distance for crest vertical curves, sag vertical curves, and horizontal curves.

1260.06 Documentation
It is recognized that some designs do not allow all criteria and guidelines to be followed as
outlined in this chapter.
Refer to Chapter 300 for design documentation requirements.

Page 1260-14 WSDOT Design Manual M 22-01.10

July 2013
Chapter 1270 Auxiliary Lanes
1201.01 General 1270.06 Emergency Escape Ramps
1270.02 Climbing Lanes 1270.07 Chain-Up and Chain-Off Areas
1270.03 Passing Lanes 1270.08 Documentation
1270.04 Slow-Moving Vehicle Turnouts 1270.09 References
1270.05 Shoulder Driving for Slow Vehicles

1270.01 General
Auxiliary lanes are used to comply with capacity demand; maintain lane balance; accommodate
speed change, weaving, and maneuvering for entering and exiting traffic; and encourage
carpools, vanpools, and the use of transit.

For signing and delineation of auxiliary lanes, see the Standard Plans, the Traffic Manual, and
the MUTCD. Contact the region Traffic Engineer for guidance.

Although slow-vehicle turnouts, shoulder driving for slow vehicles, and chain-up areas are not
auxiliary lanes, they are covered in this chapter because they perform a similar function.

For additional information, see the following chapters:

Chapter Subject
1103 Design controls, including speed
1230 Geometric cross section components
1310 Turn lanes
1310 Speed change lanes at intersections
1360 Collector-distributor roads
1360 Weaving lanes
1410 High-occupancy vehicle lanes

1270.02 Climbing Lanes

1270.02(1) General
Climbing lanes (see Exhibit 1270-1) are normally associated with truck traffic, but they may also
be considered in recreational or other areas that are subject to slow-moving traffic. Climbing
lanes are designed independently for each direction of travel.

1270.02(2) Climbing Lane Warrants

Generally, climbing lanes are provided when two warrants—speed reduction and level of
service—are met. Either warrant may be waived if, for example, slow-moving traffic is causing
an identified collision trend or congestion that could be corrected by the addition of a climbing
lane. However, under most conditions, climbing lanes are built when both warrants are met.
1270.02(2)(a) Warrant No. 1: Speed Reduction

Exhibit 1270-2a shows how the percent and length of grade affect vehicle speeds. The data is
based on a typical commercial truck.

WSDOT Design Manual M 22-01.14 Page 1270-1

July 2017
Auxiliary Lanes Chapter 1270

The maximum entrance speed, shown in the graphs, is 60 mph. This is the maximum value
regardless of the posted speed of the highway. When the posted speed is above 60 mph, use 60
mph in place of the posted speed. Examine the profile at least ¼ mile preceding the grade to
obtain a reasonable approach speed.

If a vertical curve makes up part of the length of grade, approximate the equivalent uniform
grade length.

Whenever the gradient causes a 10 mph speed reduction below the posted speed limit for a
typical truck for either two-lane or multilane highways, the speed reduction warrant is met (see
Exhibit 1270-2b).
1270.02(2)(b) Warrant No. 2: Level of Service (LOS)

The level of service warrant for two-lane highways is met when the upgrade traffic volume
exceeds 200 vehicles per hour and the upgrade truck volume exceeds 20 vehicles per hour. On
multilane highways, a climbing lane is warranted when a capacity analysis shows the need for
more lanes on an upgrade than on a downgrade carrying the same traffic volume.

Exhibit 1270-1 Climbing Lane Example

1270.02(3) Climbing Lane Design

When a climbing lane is justified, design it in accordance with Exhibit 1270-3. Provide signing
and delineation to identify the presence of the auxiliary lane. Begin climbing lanes at the point
where the speed reduction warrant is met and end them where the warrant ends for multilane
highways and 300 feet beyond for two-lane highways. Consider extending the auxiliary lane over
the crest to improve vehicle acceleration and sight distance.

Design climbing lane width equal to that of the adjoining through lane and at the same cross
slope as the adjoining lanes. Whenever possible, maintain a shoulder width equal to the
adjacent roadway segments (preserve shoulder width continuity). On two-way two-lane
highways, the shoulder may be reduced to 4 feet. If the shoulder width is reduced to 4 feet
document the reasoning for the decision in the design parameter sheets. If the shoulder width is
reduced to less than 4 feet, a design analysis is required.

Page 1270-2 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1270 Auxiliary Lanes

Exhibit 1270-2a Speed Reduction Warrant: Performance for Trucks

1% 2% 3% 4% 5% 7%
15,000
6%

10,000

Distance on Grade, L (ft)

0%

5,000

-1%

-2%

-3%
-4%

0
60 50 40 30 20 10 0
Speed (mph)

WSDOT Design Manual M 22-01.14 Page 1270-3

July 2017
Auxiliary Lanes Chapter 1270

Exhibit 1270-2b Speed Reduction Warrant Example

-4% -3% -2% -1% 0%
60
1%
700'
50  
2%
1,000'
40 
3%

Speed (mph)

4%
30
5%
6%
20 7%
1,200'

4,000'

10

0
0 5,000 10,000 15,000
Distance on Grade, L (ft)

1% Grade,
1% Grade 0 ft
L=L1= 00
,010,0 ft
2% 2% G
d,e000 ft Gra
Sp e e Sp e e G=ra4
4e%, L d e ra d e

41 mph
d ft
Gr L= 4, 0
35 mph

60 m d a 0
35 mph

41 mph
60 d 0
p h mp h 4%

50 mph

50 mph
2,800 ft 1,000 ft 700 ft
2,800 ft 1,000 ft 700 ft
50 mph

300 ft
50 mph

300 ft
60 mph

2 3 4
60 mph

1,200 ft 4,800 ft
1,200 ft 4,800 ft
Given:
A two-lane highway meeting the level of service warrant, with the above profile, and a 60 mph posted
speed.
Determine:
Is the climbing lane warranted? If so, what is its length?
Solution:
1. Follow the 4% grade deceleration curve from a speed of 60 mph to a speed of 50 mph at 1,200 ft.
The speed reduction warrant is met and a climbing lane is needed.
2. Continue on the 4% grade deceleration curve to 4,000 ft. Note that the speed at the end of the 4%
grade is 35 mph.
3. Follow the 1% grade acceleration curve from a speed of 35 mph for 1,000 ft. Note that the speed at
the end of the 1% grade is 41 mph.
4. Follow the -2% grade acceleration curve from a speed of 41 mph to a speed of 50 mph, ending the
speed reduction warrant. Note that the distance is 700 ft.
5. The total auxiliary lane length is (4,000-1,200)+1,000+700+300=4,800 feet. 300 ft is added to the
speed reduction warrant for a two-lane highway (see 1270.02(3) and Exhibit 1270-3).

Page 1270-4 WSDOT Design Manual M 22-01.14

July 2017
Chapter 1270 Auxiliary Lanes

Exhibit 1270-3 Auxiliary Climbing Lane

WSDOT Design Manual M 22-01.14 Page 1270-5

July 2017
Auxiliary Lanes Chapter 1270

1270.03 Passing Lanes

1270.03(1) Passing Lane Benefits

A passing lane (see Exhibit 1270-4) is an auxiliary lane provided in one or both directions of
travel on a two-lane highway to improve passing opportunities. They may be intermittent or
continuous passing lanes in level or rolling terrain and short four-lane sections. The objectives of
passing lanes are to:
 Improve overall traffic operations on two-lane highways by breaking up traffic platoons
and reducing delays caused by inadequate passing opportunities over substantial
lengths of highway.
 Increase average travel speed within the passing lane itself; the speed benefits of
passing lanes continue downstream of the lane. Passing lanes typically reduce the
percent time spent following within the passing lane itself. These “percent time spent
following” benefits can continue for some distance downstream of the passing lane.
 Improve safety by providing assured passing opportunities without the need for the
passing driver to use the opposing traffic lane. Safety evaluations have shown that
passing lanes and short four-lane sections reduce collision rates and severity.

1270.03(2) Passing Lane Length

Design passing lanes long enough to provide a reduction in traffic platooning. To maximize the
traffic operational efficiency of a passing lane in level or rolling terrain, its length can vary from
0.5 mile to 2.0 miles depending on the directional flow rate, as shown in Exhibit 1270-5. Passing
lanes longer than 2 miles can cause the driver to lose the sense that the highway is a two-lane
facility. However, these lengths may vary for other reasons such as addressing safety-related
issues. Passing lanes longer than 2.0 miles or shorter than 0.5 miles in length may be used
depending on the identified need or other operational considerations within the design. Lengths
shown do not include passing lane tapers at the beginning or end of the passing lane.
Exhibit 1270-4 Passing Lane Example

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Exhibit 1270-5 Length of Passing Lanes

Directional Flow Rate (pc/h) Passing Lane Length (mi)

100 ≤0.50

200 >0.50-0.75

400 >0.75-1.00

≥700 >1.00-2.00
Source: Transportation Research Board, Highway Capacity Manual, 2000

For assistance in developing a passing lane length, see the following website for an example of a
self-modeling spreadsheet. This spreadsheet develops passing lane lengths based primarily on
vehicle speed differentials and is to be used in conjunction with traffic modeling efforts. Contact
the Headquarters Design Office for assistance
( www.wsdot.wa.gov/design/policy/default.htm).

1270.03(3) Passing Lane Location

A number of factors are considered when selecting an appropriate location for a passing lane,
including the following:
 Locate passing lanes where decision sight distance (see Chapter 1260) at the lane
decrease tapers can be provided.
 Provide stopping sight distance continuously along the roadway
 Avoid locating passing lanes near high-volume intersections, existing structures,
railroad crossings, areas of dense development, and two-way left-turn lanes.
 Locate passing lanes where they appear logical to the driver.
 Carefully consider highway sections with low-speed curves (curves with superelevation
less than required for the design speed) before installing a passing lane, since they may
not be suitable for passing. For information on superelevation, see Chapter 1250.
 Avoid other physical constraints, such as bridges and culverts, if they restrict the
provision of a continuous shoulder.
 Consider the number, type, and location of intersections and road approaches.
 Consider grades when choosing the side on which to install the passing lane. Uphill
grades are preferred but not mandatory.
 Preference for passing is normally given to the traffic departing a developed area such
as a small town.

1270.03(3)(a) Traffic Operational Considerations

When passing lanes are provided at an isolated location, their typical objective is to reduce
delays at a specific bottleneck; for example, climbing lanes (see 1270.02). The location of the
passing lane is dictated by the needs of the specific traffic operational problem encountered.

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Auxiliary Lanes Chapter 1270

When passing lanes are provided to improve traffic operations over a length of road, there is
flexibility in the choice of passing lane locations to maximize their operational effectiveness and
minimize construction costs.

If delay problems on an upgrade are severe, the upgrade will usually be the preferred location
for a passing lane.

Passing lanes at upgrades begin before speeds are reduced to unacceptable levels and, where
possible, continue over the crest of the grade so that slower vehicles can regain some speed
before merging.

1270.03(3)(b) Construction Cost Considerations

The cost of constructing a passing lane can vary substantially, depending on terrain, highway
structures, shoulders, and adjacent development. Thus, the choice of a suitable location for a
passing lane may be critical to its cost-effectiveness.

Generally, passing lanes in level and rolling terrain can be placed where they are least expensive
to construct, avoiding locations with high cuts and fills and existing structures that would be
expensive to widen.
1270.03(3)(c) Intersection-Related Considerations

Consider a corridor evaluation of potential passing lane locations for each direction, avoiding
placement of passing lanes near intersections. Avoid or minimize turning movements on a road
section where passing is encouraged.

Low-volume intersections and driveways are allowed within passing lanes, but not within the
taper transition areas.

Where the presence of higher-volume intersections and driveways cannot be avoided, consider
including provisions for turning vehicles, such as left-turn lanes.

Provide right- and left-turn lanes in passing lane sections where they would be provided on a
conventional two-lane highway.

Left turns within the first 1,000 feet of a passing lane are undesirable. Strategies to address the
turning movement could include left-turn lanes, right-in/right-out access, beginning the passing
lane after the entrance, and so on.

1270.03(4) Passing Lane Design

Where a passing lane is planned, evaluate several possible configurations (see 1270.03(4)(a))
that are consistent with the corridor and fit within the constraints of the specific location.

The recommended minimum transition distance between passing lanes in opposing directions is
500 feet for “tail-to-tail” and 1,500 feet for “head-to-head” (see Exhibit 1270-7).

Some separation between lanes in opposite directions of travel is desirable; however, passing
lanes can operate effectively with no separation. In either situation, address pavement markings
and centerline rumble strips as appropriate.

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It is desirable to channelize the beginning of a passing lane to move traffic to the right lane in
order to promote prompt usage of the right lane by platoon leaders and maximize passing lane
efficiency.

Widening symmetrically to maintain the roadway crown at the centerline is preferred, including
in continuous passing lane configurations. However, the roadway crown may be placed in other
locations as deemed appropriate. Considerations for crown locations might include: costs,
constructability, right of way, environmentally sensitive roadsides, or other factors.

1270.03(4)(a) Alternative Configurations

Where a passing lane will be provided, evaluate the configurations shown in Exhibit 1270-6. In
the exhibit, general passing lane configurations and their typical applications are described in
the following:

a. Isolated Passing Lane – Exhibit 1270-6 (a)

 Two-lane highway with passing lane provided at a spot location to dissipate
queues.
 For isolated grades, consider climbing lanes (see 1270.02).

b. Intermittent Passing Lanes, Separated – Exhibit 1270-6 (b)

 Often pairs are used at regular intervals along a two-lane highway.
 Frequency of passing lanes depends on desired level of service.
 The spacing between passing lanes and between pairs may be adjusted to fit the
conditions along the route (see 1270.03(3)).

c. Continuous Passing Lanes – Exhibit 1270-6 (c)

 Use only when constraints do not allow for the use of other configurations. The use
of this configuration requires concurrence from the region Traffic Engineer. (See
Exhibit 1270-7 for additional information regarding buffer areas.)
 Appropriate for two-lane roadways carrying relatively high traffic volumes where
nearly continuous passing lanes are needed to achieve the desired level of service.
 Particularly appropriate over an extended section of roadway where a wide
pavement is already available.
 May be used as an interim stage for an ultimate four-lane highway.

d. Short Four-Lane Section – Exhibit 1270-6 (d)

 Sufficient length for adjoining passing lanes is not available.
 Particularly appropriate where the ultimate design for the highway is four lanes.

e. Intermittent Three-Lane Passing Lanes – Exhibit 1270-6 (e)

 Does not require the slow vehicle to change lanes to allow passing.
 Requires the widening to transition from one side of the existing roadway to the
other.
 Eliminates the head-to-head tapers.

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Auxiliary Lanes Chapter 1270

1270.03(4)(b) Geometric Aspects

Carefully design transitions between passing lanes in opposing directions. Intersections, bridges,
other structures, two-way left-turn lanes, painted medians, or similar elements can be used to
provide a buffer area between opposing passing lanes. The length of the buffer area between
adjoining passing lanes depends on the configuration (see Exhibit 1270-7).

Exhibit 1270-6 illustrates five passing lane design configurations. Part (c) illustrates a continuous
three-lane section with alternating passing lanes. Consider a four-lane cross section when
volume demand exceeds the capacity of a continuous three-lane roadway.

Exhibit 1270-8 illustrates taper rates, cross slopes, and section lengths for three and four-lane
passing sections. Where practicable provide shoulder width in a passing lane section equal to
the shoulder width on the adjacent segments of a two-lane highway. However, the shoulder
may be reduced to 4 feet. If the shoulder width is reduced to 4 feet, document the reason for
the decision on the design parameter sheets. If the shoulder width is reduced to less than 4 feet,
a design analysis is required. See Chapter 1600 for shoulder rumble strip criteria and
considerations.

Where practicable, design the passing lane width the same as the lane width on the adjacent
segments of the two-lane highway.

Provide a 25:1 or flatter taper rate to increase the width for a passing lane. When all traffic is
directed to the right lane at the beginning of the passing lane, provide a taper rate of the posted
speed:1. Provide a posted speed:1 taper rate for the merging taper at the end of a passing lane.
(Refer to the Lane Transitions section in Chapter 1210 for additional information on taper rates.)
Consider a wide shoulder at the lane drop taper to provide a recovery area for drivers who
encounter a merging conflict.

Provide signing and delineation to identify the presence of an auxiliary passing lane. Refer to the
Standard Plans, the Traffic Manual, and the MUTCD for passing lane signing and marking
guidance.

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Exhibit 1270-6 Passing Lane Configurations

(a) Isolated Passing Lane

(b) Intermittent Passing Lane

Head-to-head Tail-to-tail Head-to-head Tail-to-tail

buffer[1] buffer[1] buffer[1] buffer[1]

(c) Continuous Three-Lane Section

(d) Short Four-Lane Section

Tail-to-tail
buffer[1]

(e) Intermittent Three-Lane Passing Lanes

Note:

[1] See Exhibit 1270-7 for buffer design.

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Auxiliary Lanes Chapter 1270

Exhibit 1270-7 Buffer Between Opposing Passing Lanes

1500 ft min
“Head to head” buffer
Taper peed:1
er
or flatt
S
Posted

500 ft min
“Tail to tail” buffer
25:
1

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Chapter 1270 Auxiliary Lanes

Exhibit 1270-8 Auxiliary Passing Lane

4-Lane Design 3-Lane Design

ape [1]
or flatt r
er
25:1 T

eed:1

eed:1
tter

tter
fla

fla
Posted Sp

Posted Sp
r

r
o

Taper o
Ta p e r

Constant cross slope Constant cross slope

1,500 ft min
1,500 ft min

2 mi max
2 mi max

Through traffic

Through traffic
Through traffic

Through traffic
eed:1
fla tter
Posted Sp
Tape r o r

ape [1]
ape [1]

or flatt r
or flatt r

er
er

25:1 T
25:1 T

Notes:
[1] Provide a posted speed:1 taper when all traffic is directed to the right lane at the beginning of the
passing lane.
[2] Where practicable provide the same lane and shoulder widths in the passing section as on adjacent
segments. See 1270.03(4)(b).

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Auxiliary Lanes Chapter 1270

1270.04 Slow-Moving Vehicle Turnouts

1270.04(1) General
RCW 46.61.427 states:

On a two-lane highway where passing is unsafe … a slow-moving vehicle, behind which

five or more vehicles are formed in a line, shall turn off the roadway wherever sufficient
area for a safe turn-out exists, in order to permit the vehicles following to proceed…

A slow-moving vehicle turnout is not an auxiliary lane. Its purpose is to provide sufficient room
for a slow-moving vehicle to pull out of through traffic and stop if necessary, allow vehicles to
pass, and then return to the through lane. Generally, a slow-moving vehicle turnout is provided
on existing roadways where passing opportunities are limited, where slow-moving vehicles such
as trucks and recreational vehicles are predominant, and where the cost to provide a full
auxiliary lane would be prohibitive.

1270.04(2) Design
Base the design of a slow-moving vehicle turnout primarily on sound engineering judgment.
Designs may vary from one location to another. Provide a length between 100 and 1,320 feet,
excluding tapers. Select a width adequate for the vehicle type expected to use the turn-out,
between 8 to 12 feet in width. Surface the turnouts with a stable, unyielding material (such as
BST or HMA) with adequate structural strength to support the heavier traffic.

To improve the ability of a vehicle to safely reenter through traffic, locate slow-moving vehicle
turnouts where adequate sight distance is available. The minimum design range for slow-vehicle
turnouts may be where at least design stopping sight distance is available. See Chapter 1260.

Sign slow-moving vehicle turnouts to identify their presence. For guidance, see the Standard
Plans, the Traffic Manual, and the MUTCD.

1270.05 Shoulder Driving for Slow Vehicles

1270.05(1) General
Use of a shoulder driving section is an alternative means to meet the performance objectives
provided by climbing or passing lanes.

Review the following when considering a shoulder driving section:

• Horizontal and vertical alignment

• Character of traffic

• Presence of bicycles

• Road approaches and intersections

• Clear zone (see Chapter 1600)

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1270.05(2) Design
When designing a shoulder for shoulder driving, locate where full design stopping sight distance
(speed/path/direction decision sight distance is desirable) and a minimum length of 600 feet are
available. Where practicable, avoid sharp horizontal curves. When barriers or other roadside
objects are present, the minimum width is 12 feet. The shoulder width depends on the vehicles
that will be using the shoulder. Where trucks will be the primary vehicle using the shoulder, use
a 12-foot width; when passenger cars are the primary vehicle, a 10-foot width may be used.

Shoulder driving and bicycles are not compatible. When the route has been identified as a local,
state, or regional significant bike route, shoulder driving for slow vehicles is undesirable.
Reconstruct the shoulders to provide adequate structural strength for the anticipated traffic.
Select locations where the side slope meets the criteria of Chapter 1239. When providing a
transition at the end of a shoulder driving section, use a 50:1 taper.

Signing for shoulder driving is required (see the Standard Plans, the Traffic Manual, and the
MUTCD). Install guideposts when shoulder driving is to be permitted at night.

1270.06 Emergency Escape Ramps

1270.06(1) General
Consider an emergency escape ramp (see Exhibit 1270-9) whenever a long, steep downgrade is
encountered. In this situation, the possibility exists of a truck losing its brakes and going out of
control at a high speed. Consult local maintenance personnel and check crash data to determine
whether or not an escape ramp is justified.
Exhibit 1270-9 Emergency Escape Ramp Example

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1270.06(2) Design
1270.06(2)(a) Types

Escape ramps include the following types:

 Gravity escape ramps are ascending grade ramps paralleling the traveled way. They are
commonly built on old roadways. Their long length and steep grade can present the
driver with control problems, not only in stopping, but with rollback after stopping.
Gravity escape ramps are the least desirable design.
 Sand pile escape ramps are piles of loose, dry sand dumped at the ramp site, usually
not more than 400 feet in length. The deceleration is usually high and the sand can be
affected by weather conditions; therefore, they are less desirable than arrester beds.
However, where space is limited, they may be suitable.
 Arrester beds are parallel ramps filled with smooth, free-draining gravel. They stop the
out-of-control vehicle by increasing the rolling resistance and are the most desirable
design. Arrester beds are commonly built on an upgrade to add the benefit of gravity to
the rolling resistance. However, successful arrester beds have been built on a level or
descending grade.
 The Dragnet Vehicle Arresting Barrier consists of chain link or fiber net that is attached
to energy-absorbing units. (See Chapter 1610 for additional information.)
1270.06(2)(b) Locations

The location of an escape ramp depends on terrain, length of grade, sight distance, and roadway
geometrics. Desirable locations include before a critical curve, near the bottom of a grade, or
before a stop. It is desirable that the ramp leave the roadway on a tangent at least 3 miles from
the beginning of the downgrade.
1270.06(2)(c) Lengths

The length of an escape ramp depends on speed, grade, and type of design used. The minimum
length is 200 feet. Calculate the stopping length using the equation in Exhibit 1270-10.
Exhibit 1270-10 Emergency Escape Ramp Length

V2
L
0.3R  G 
Where:
L = Stopping distance (ft)
V = Entering speed (mph)
R = Rolling resistance (see Exhibit 1270-11)
G = Grade of the escape ramp (%)

Speeds of out-of-control trucks rarely exceed 90 mph; therefore, the desirable entering speed is
90 mph. Other entry speeds may be used when justification and the method used to determine
the speed are documented.

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Exhibit 1270-11 Rolling Resistance (R)

Material R
Roadway 1

Loose crushed aggregate 5

Loose non-crushed gravel 10

Sand 15

Pea gravel 25

1270.06(2)(d) Widths

The width of each escape ramp depends on the needs of the individual situation. It is desirable
for the ramp to be wide enough to accommodate more than one vehicle. The desirable width of
an escape ramp to accommodate two out-of-control vehicles is 40 feet and the minimum width
is 26 feet.

The following items are additional considerations in the design of emergency escape ramps:
 If possible, at or near the summit, provide a pull-off brake check area. Also, include in
this area informative signing about the upcoming escape ramp.
 Free-draining, smooth, non-crushed gravel is desirable for an arrester bed. To assist in
smooth deceleration of the vehicle, taper the depth of the bed from 3 inches at the
entry to a full depth of 18 to 30 inches in not less than 100 feet.
 Mark and sign in advance of the ramp. Discourage normal traffic from using or parking
in the ramp. Sign escape ramps in accordance with the guidance contained in the
MUTCD for runaway truck ramps.
 Provide drainage adequate to prevent the bed from freezing or compacting.
 Consider including an impact attenuator at the end of the ramp if space is limited.
 A surfaced service road adjacent to the arrester bed is needed for wreckers and
maintenance vehicles to remove vehicles and make repairs to the arrester bed.
Anchors are desirable at 300-foot intervals to secure the wrecker when removing
vehicles from the bed.

Typical examples of arrester beds are shown in Exhibits 1270-9 and 1270-12.

Include justification, all calculations, and any other design considerations in the emergency
escape ramp documentation.

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Auxiliary Lanes Chapter 1270

Exhibit 1270-12 Typical Emergency Escape Ramp

Wrecker anchors

Service road

Arrester bed

Length

G2

G1

Escape ramp grade

Main line grade

1270.07 Chain-Up and Chain-Off Areas

Provide chain-up areas to allow chains to be put on vehicles out of the through lanes at
locations where traffic enters chain enforcement areas. Provide chain-off areas to remove
chains out of the through lanes for traffic leaving chain enforcement areas.

Chain-up or chain-off areas are widened shoulders, designed as shown in Exhibit 1270-13.
Locate chain-up and chain-off areas where the grade is 6% or less and desirably on a tangent
section.

Consider illumination for chain-up and chain-off areas on multilane highways. When deciding
whether or not to install illumination, consider traffic volumes during the hours of darkness and
the availability of power.

The wide shoulders at chain-up and chain-off areas may encourage parking. When parking is
undesirable, consider parking restrictions.

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Exhibit 1270-13 Chain-Up/Chain-Off Area

CL

Edge of traveled way

Edge of shoulder
Through traffic

5 0: 1

20 ft min[1]
165 ft min

Constant
cross slope[2]
1
2 5:

Notes:
[1] Where traffic volumes are low and trucks are not a concern, the width may be reduced to 10 ft min,
with 15 ft desirable.
[2] 2% desirable. (See Chapter 1250 for traveled way cross slope.)

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Auxiliary Lanes Chapter 1270

1270.08 Documentation
Refer to Chapter 300 for design documentation requirements.

1270.09 References

1270.09(1) Federal/State Laws and Codes

Revised Code of Washington (RCW) 46.61, Rules of the road

1270.09(2) Design Guidance

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

Traffic Manual, M 51 02, WSDOT

1270.09(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition

Emergency Escape Ramps for Runaway Heavy Vehicles, FHWA-T5-79-201, March 1978

Highway Capacity Manual, latest edition, Transportation Research Board, National Research
Council

Truck Escape Ramps, NCHRP Synthesis 178, Transportation Research Board

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Chapter 1300 Intersection Control Type
1300.01 General
1300.02 Intersection Control Objectives
1300.03 Common Types of Intersection Control
1300.04 Modal Considerations
1300.05 Procedures
1300.06 Documentation
1300.07 References

1300.01 General
It is WSDOT practice to analyze potential intersection solutions at all intersection improvement
locations in accordance with E 1082 – Business Practices for Moving Washington and E 1090 –
Moving Washington Forward: Practical Solutions. The objective is to provide the optimum
solution within available resources, with an emphasis on low-cost investments. The analysis can
be done for individual intersections, or on a corridor or network basis. This chapter provides
guidance on preliminary intersection analysis and selection of control type. Intersection design
is completed using Chapter 1310 for the geometrics of intersections, Chapter 1320 for
roundabouts, and Chapter 1330 for traffic signals. Use the aforementioned chapters in
conjunction with chapters 1106, 1230 series, 1430, 1510, and 1520 to assist with dimensioning
design elements.

Consider design users and the balance between modes, safety and mobility performance
considerations, context-sensitive/sustainable design, and economics when selecting and
evaluating alternatives to meet the needs of the project.

Identification of intersection projects can come from a variety of programs and sources,
including those funded by local agencies and developers. The intent of this chapter is that the
procedures apply to all types of intersection modifications on the state highway system.
Potential safety project locations are identified through the safety priority programming
process. Other programs may identify intersection needs through the priority programming
process, but the influence of the type of intersection control with respect to specific
performance category needs may not be fully understood until contributing factors analysis is
completed (see Chapter 1101).

Complete an Intersection Control Evaluation (ICE), formerly known as Intersection Control

Analysis (ICA), as early as practicable, taking into account the level of community engagement
that may need to occur prior to approval. The ICE (see 1300.05 for procedures) should be
considered a working document that is initiated no later than the scoping phase so that the
scope and schedule are compatible with the chosen intersection type. Scale the ICE according
to the size and complexity of the project; for example, evaluation of adding a turn lane to an
existing intersection control may take less effort than evaluating new intersection control.
Consult the region or HQ Traffic offices for assistance with the level of effort required.

It is WSDOT policy to focus on lower cost solutions with the intent to optimize return on
investment. Only when all at-grade intersection alternatives are ruled out, including turn
restrictions and complete intersection removal, should other more-costly measures be
considered, such as grade-separation. Ramp terminal intersections are subject to the analysis
requirements of this chapter. See chapters 1360 and 550 for additional information.

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Intersection Control Type Chapter 1300

For additional information, see the following chapters:

Chapter Subject
320 Traffic analysis
321 Sustainable Safety Analysis
530 Limited access control
540 Managed access control
550 Access Revision Report
1100 Practical Design
1101 Need Identification
1103 Design Controls
1106 Design Element Dimensioning
1230 Geometric Cross Section Basics; and other 1230 series chapters
1310 Intersections
1320 Roundabouts
1330 Traffic signals
1340 Driveways
1360 Interchanges
1510 Pedestrian facilities
1515 Shared-use paths
1520 Bicycle facilities

1300.02 Intersection Control Objectives

Intersections are an important part of highway design. Intersection control choice requires
consideration of all potential users of the facility, including drivers of motorcycles, passenger
cars, heavy vehicles of different classifications, public transit, and bicyclists and pedestrians.

Design users have varying skills and abilities. Younger and older drivers in particular are subject
to a variety of behavioral or human factors that can influence elements of their driving ability.
See NCHRP Report 600 – Human Factors Guidelines for Road Systems: Second Edition for
additional information (http://www.trb.org/Main/Blurbs/167909.aspx). Bicyclists, from
recreational to commuters, also have a variety of skill sets that can influence the effectiveness
of bike facilities and intersection operational design (see Chapter 1520 for additional
information). Meeting the needs of one user group can directly influence the service that other
groups experience. The selection process evaluates these competing needs and results in an
optimal balance of tradeoffs for all design users, recognizing the context and priorities of the
location.

The intent of an ICE is not to design an intersection, but to evaluate the compatibility of
different intersection control types with respect to context, modal priority, intersection design
vehicle, and the identified balance of performance needs. Four basic intersection design
consideration categories are shown in Exhibit 1300-1 and can affect the intersection control
types depending on the situation.

The objectives of the ICE are to:

 Provide a consistent framework to determine the most compatible intersection control
type for the location, context, economics, and balance of performance needs.
 Evaluate the operational and safety performance for various appropriate and feasible
intersection control types under consideration.

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Chapter 1300 Intersection Control Type

 Evaluate the modal performance considerations between different intersection control

types with respect to the identified modal priority and intersection design vehicle (see
Chapter 1103). Identify the potential modal treatments that augment the control
types.
 Consider the intersection operations and the relationship with adjacent intersections
and other access points.
 Evaluate the intersection control types for potential sustainability, community value,
and expected maintenance and operation needs.
 Include roundabouts in all intersection control evaluations due to their safety,
operational, and sustainability benefits.
 Consider emerging alternative intersection designs such as displaced left-turn (DLT)
and restricted crossing u-turn intersections (RCUT) where appropriate.
 Select the intersection control type for the project based on overall need and context.

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Intersection Control Type Chapter 1300

Exhibit 1300-1 Intersection Design Considerations

Human Factors
 Conformance to natural paths of
 Driving habits
movement
 Driver workload
 Pedestrian use and habits
 Driver expectancy
 Bicycle traffic use and habits
 Driver error
 Visual recognition of roadway cues
 Driver distractions
 Compatibility with context characteristics
 Perception-reaction time
 Demand for alternative mode choices
Traffic Considerations

 Design users, modal priority, and  Vehicle size and operating characteristics
intersection design vehicle  Vehicle speeds
 Design and actual capacities  Transit involvement
 Design-hour turning movements  Crash Experience
 Variety of movements  Bicycle movements
(diverging/merging/weaving/crossing)  Pedestrian movements
Physical Elements
 Traffic control devices
 Character and use of abutting property
 Illumination
 Vertical alignments at the intersection
 Roadside design features
 Sight distance
 Environmental factors
 Angle of the intersection
 Crosswalks
 Conflict areas
 Transit facilities
 Speed-change lanes
 Driveways
 Managed lanes (HOV, HOT, shoulder)
 Streetside design features
 Accessible facilities
 Adjacent at-grade rail crossing
 Parking zones
 Access management treatments including
 Geometric design features
turn restrictions
Economic Factors
 Cost of improvements, annual maintenance, operations and life cycle costs, and salvage value
 Effects of controlling access and right of way on abutting properties where channelization
restricts or prohibits vehicular movements
 Energy consumption and emissions

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1300.03 Common Types of Intersection Control

1300.03(1) Uncontrolled Intersections

 Uncontrolled intersections do not have signing, and
the normal right of way rule (RCW 46.61.180) applies.
 This intersection type is typically found on local roads
and streets where the volumes of the intersecting
roadways are low and roughly equal, speeds are low,
and there is little to no crash history.
 Uncontrolled intersections are not recommended for
state routes.

1300.03(2) Yield Control

 Intersections with yield control assign right of way without
requiring a stop.
 Mostly used at rural low-volume ramps and wye (Y) intersections.
 Yield control is generally not recommended in urban locations or
where pedestrians are expected.

1300.03(3) Two-Way Stop Control

 Intersections with two-way stop control are a common, lower cost control, which
require the traffic on the minor roadway to stop and yield to mainline traffic before
entering the major roadway.
 Along certain corridors, especially where u-turn opportunities exist, consider limiting
access at two-way stops to “right-in, right-out only.”

1300.03(4) Multi-Way Stop Control

 Multi-way stop control normally requires all
traffic to stop before entering the intersection.
 Fewer fatal and injury crashes than two-way
stop control.
 Multi-way stop control is suited for lower
speed facilities with approximately equal
volumes on all legs and total entering volumes
not exceeding 1,400 vehicles during the peak
hour.
 Increased traffic delays, fuel consumption, and
air pollution.
 Multi-way stop control is not recommended on multilane state routes or at
intersections with unbalanced directional traffic flows because of the delays and
queues introduced on the major-volume legs of the intersection.

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1300.03(5) Roundabouts
Roundabouts are often circular (or near-circular) at-grade intersections, where traffic on the
approaches yield to traffic within the circulating roadway. Roundabouts are an effective
intersection type that may offer the following:
 Reduced fatal and injury crashes compared
with other at-grade intersection types.
 Fewer conflict points.
 Lower potential for wrong-way driving.
 Reduced traffic delays.
 Traffic-calming and lower speeds.
 More capacity than a two-way or multi-
way stop.
 Quickly serves pedestrians needing to
cross the intersection and shortens
crossing distance for pedestrians by allowing for crossing in stages using splitter islands
as pedestrian refuges.
 Reduced vehicular approach speeds that result in reduced crash and severity potential
to pedestrians.
 Ability to serve high turning volumes with minimal number of approach lanes.
 Improved operations where space for queuing is limited.
 Improved capacity at ramp terminals intersections with high left-turn volumes without
affecting the structure.
 Facilitation of u-turn movements and can be appropriate when combined with access
management along a corridor.
 Aesthetic treatments and gateways to communities.
 Flexibility to fit funding and a variety of site constraints. Roundabouts are scalable and
site-specific solutions. See Chapter 1320 for more information on roundabout types
and design.

1300.03(6) Traffic Control Signals

Signalized intersections may offer the following:
 Increased capacity of the intersection compared to stop-controlled intersections.
 Allow for improved progression within a coordinated system along a corridor or a grid.
 Can be used to interrupt heavy traffic at intervals to permit other traffic, vehicular or
pedestrian, to complete their movement or enter the intersection.
 Can be preempted to provide priority service to railroad, emergency responders,
transit and approaches where advance queue loops are used.
 Reduced at-angle vehicle crashes compared to stop-controlled intersections.

However, signalized intersections:

 Require continual maintenance and engineering for optimal operations.

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 Cannot adequately balance large traffic flows with pedestrian demands.

 Can be susceptible to power outages and detection failures.
 Increase rear-end crashes.

Indiscriminate use of traffic signals can adversely affect the safety performance and operational
efficiency of vehicle, bicycle, and pedestrian traffic. Therefore, and as required by the MUTCD, a
traffic signal should be considered for installation only after if it is determined to meet specific
“warrants” and an engineering study shows that the installation would improve safety and/or
operations. Satisfying a signal warrant does not mandate the installation of a traffic signal nor by
itself meet the requirements of 1300.05; but failing to satisfy at least one warrant shall remove
the signal from consideration.

Not all crashes are correctable with the installation of a traffic signal. Traffic signals may
decrease the potential for crashes of one type and increase the potential for another type. For
instance, at-angle crashes are less frequent with signals because the traffic movements are
controlled, but rear-end crashes are more frequent with signals because of stopping and starting
of vehicles. At-angle crashes are usually more severe than rear-end crashes; however, the
severity of these rear-end crashes tend to be higher at operating speeds above 40 mph. This
requires careful consideration of the location characteristics, traffic flow, and crash history.

State statutes (RCW 46.61.085) require WSDOT approval for the design and location of all
conventional traffic signals and for some types of beacons located on city streets forming parts
of state highways. The Traffic Signal Permit (DOT Form 242-014 EF) is the formal record of the
department’s approval of the installation and type of signal. For traffic signal permit guidance,
see Chapter 1330.

1300.03(7) Alternative Intersections

Alternative intersections work mainly by rerouting U and left turns, and/or separating
movements. Alternative intersections may have different terminology in different areas, but the
most common types include:
 Median u-turn  Split intersection
 Jug handle  Quadrant roadway intersection
 Bowtie  Single quadrant interchange
 Restricted crossing u-turn  Echelon
 Displaced left-turn intersection  Center turn overpass
 Continuous green tee

As alternative intersections may be relatively new to Washington State and its users, more
education and community engagement will be necessary to help ensure project success.
However, extensive experience shows that many of these intersection types can provide better
operational and safety performance, often at much less cost than traditional strategies.

Three types of alternative intersections are highlighted in the subsections below: median u-turn,
restricted crossing u-turn, and displaced left-turn intersections. For more information about
these and other intersection design solutions, see the Federal Highway Administration (FHWA)
Alternative Intersection Design web page:
http://safety.fhwa.dot.gov/intersection/alter_design/

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1300.03(7)(a) Median U-Turn (MUT)

The MUT intersection treatment relocates left turn movements downstream from the
intersection resulting in lower delays, higher throughput, and reduction in the number and
severity of crashes. Left-turning drivers proceed straight through the at-grade intersection, and
then execute a u-turn at some distance downstream at a new or existing median opening. The
main intersection is typically signalized and can be highly efficient needing only two signal
phases. By removing the left turns at the main intersection, the MUT design results in a
significant reduction in rear-end, angle, and sideswipe crashes; while reducing the number of
conflict points from 32 to 16 when compared to a conventional signalized intersection. The MUT
can also have advantages for pedestrians with fewer conflict points and a lower delay. However,
the intersection design may reduce bicyclist mobility as they are expected to use the pedestrian
crossings in order to perform left turns at the intersection. The MUT intersection design is more
likely to be suitable for consideration in situations where:
 The intersection is over capacity.
 There are heavy through volumes and low to moderate left turn volumes.
 The intersection is within a higher-speed, multilane, median-divided corridor.
 There are safety concerns at an existing signalized intersection or corridor.

Refer to FHWA’s Median U-Turn Intersection Informational Guide for geometric design
considerations and recommendations. (See Chapter 1310 for geometrics when designing the
u-turn movement for the MUT intersection.)

Exhibit 1300-2 Median U-Turn Intersection Example

MUT Intersection from FHWA’s Median U-Turn Intersection Informational Guide

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1300.03(7)(b) Restricted Crossing U-Turn Intersection (RCUT)

RCUT intersections, also known as superstreets or J-turns, have similarities with the MUT in that
the minor road left-turning movements are redirected (see Exhibit 1300-2). RCUTs, however,
also redirect minor road through movements as shown in Exhibit 1300-3. This intersection type
results in lower delays, improved progression, and a potential reduction in the total number of
crashes and fatal and injury crashes.

Drivers on the minor road approaches must turn right onto the major road and then perform a
u-turn maneuver at a median opening downstream. However, the major road left turn
movements may still be allowed at the main intersection. RCUT intersections may or may not
warrant signalization due to traffic volumes, and those with signalization require fewer signal
phases and shorter cycle lengths than a traditional signalized intersection. The RCUT
intersection is more likely suitable for consideration in situations where:
 The intersection is over capacity.
 There is a need to improve travel time and progression for the major road.
 There are crashes at the intersection related to turning movements that can be
reduced by a RCUT.
 The intersection is within a higher-speed, multilane corridor.
 There are low through and left turn volumes on the minor road.
 Pedestrian volumes are low.
 The major roadway contains sufficient median width, or total right of way width, to
support the u-turn movements.
Exhibit 1300-3 Restricted Crossing U-Turn Intersection Example with Stop-control

Example of RCUT Intersection with stop-control from FHWA’s Restricted Crossing U-Turn Intersection Informational Guide

The RCUT intersection may be a potential alternative compared to a grade-separated

interchange, at locations meeting grade-separated considerations identified in 530.04(3). Refer
to FHWA’s Restricted Crossing U-Turn Intersection Informational Guide for geometric design
considerations and recommendations. (See Chapter 1310 for geometrics when designing the
u-turn movement for the RCUT.)

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1300.03(7)(c) Displaced Left-Turn Intersection (DLT)

The DLT intersection, also known as a continuous flow intersection, works mainly by relocating
one or more left turn movements to the other side of the opposing traffic via an interconnected
signalized crossover. This essentially causes the traffic signal system to be more efficient by
eliminating the left turn phase at the main intersection allowing for more green time to be
allocated to other movements. The DLT can reduce delays by up to 40%, but often can be
delivered for just slightly more cost than a typical signalized intersection. Compared with a
conventional intersection, the DLT can be more challenging for pedestrians due to longer
crossing distances and counter-intuitive left turn vehicular movements. However, the DLT
typically has shorter cycle lengths and potentially shorter delays. The DLT intersection design is
best applied in situations where:
 There are high left-turn and through volumes.
 Intersection is over capacity.
 There are excessive delays and queuing, especially when left turn queues extend past
the available storage bays.
 Pedestrian volumes are low.
 Sufficient right-of-way exists on the leg(s) that need to be widened to accommodate
the new lanes.
 Context is urban/suburban.
Exhibit 1300-4 Displaced Left Turn Intersection Example

Example of DLT Intersection from FHWA’s Displaced Left Turn Intersection Informational Guide

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1300.04 Modal Considerations

When designing a multimodal intersection, consideration needs to be given to all design users at
the intersection, the intersection design vehicle and selected modal priority (see Chapter 1103).

It is not appropriate to design for specific modal treatments on the outset of evaluating
intersection control types. However, modally oriented intersection treatments may be
necessary to enhance specific modal baseline or contextual performance needs (see Chapter
1101), and may influence the control type selection. Include a discussion of the potential
modally oriented treatments relevant to the control types being analyzed and modal
performance needs. Evaluate the potential effect of modal specific treatments on all design
users relevant for the control types evaluated in the ICE.

1300.04(1) Pedestrian Considerations

Consider the intersection type and how it accommodates pedestrians. With each intersection
type, there may be specific elements and/or treatments applicable for pedestrians (see, for
example chapters 1231 and 1510) to meet modal performance needs identified (see Chapter
1101).

For example, a signalized intersection with a long cycle length, high vehicle speeds, or frequent
permitted turning movements is generally not appropriate for areas with moderate to high
pedestrian demand. However, a roundabout or responsive signal in an urban downtown core
with low speeds is typically well respected with high compliance and short delays.

Roundabouts often accommodate pedestrian crossings because of high motorist compliance

rates, short delays, and minimal disruption to vehicular traffic flow due to short crossing
distances, reduced vehicular speeds, and two-stage crossings. Additional strategies may be
utilized at multi-lane roundabouts if the pedestrian network and context supports enhanced
pedestrian crossings.

Additional information on emerging practices to address pedestrian performance needs for

different intersection control types can be found at the Pedestrian and Bicycle Information
Center (http://www.pedbikeinfo.org/).

For signalized intersections, sidewalk and ramp designs have additional requirements to
accommodate the pedestrian features of the traffic signal system (see Chapter 1330).

1300.04(2) Bicycle Considerations

For consideration of bicycle needs at intersections and treatments that may have an operational
effect on other design users, see chapters 1515 and 1520. Additional emerging practice
information to address bicycle performance needs for different intersection control types can be
found at the Pedestrian and Bicycle Information Center (http://www.pedbikeinfo.org/) and the
NACTO Urban Bikeway Design Guide (https://nacto.org/publication/urban-bikeway-design-
guide/).

1300.04(3) Transit Considerations

When transit vehicles are identified as a modal priority, consider treatments to meet the
performance needs of the specific transit vehicle types and their effect on the performance of
other design users (see Chapter 1103). Transit oriented treatments can vary significantly

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depending on the proximity of stop locations with respect to the intersection location and origin
of the transit movement (see Chapter 1430 for bus stop placement guidelines), and the type of
transit vehicle (such as a fixed guideway vehicle). Discuss treatment options and any operating
restrictions the transit provider may have regarding different intersection control types.

1300.04(4) Operational Considerations

Traditional delay analysis focuses on determining the peak-hour letter-graded Level of Service
(LOS) of an individual intersection. However, as this approach often does not account for
multimodal users and as roughly 80% of the daily traffic volumes occur outside of the peak
hours, a more encompassing review of the intersection is needed to provide sufficient
multimodal capacity and safety performance at all hours of the day.

Intersection control can have an influence on road user behavior and modal operations, not just
at the intersection itself, but also along the corridor or surrounding network, even when the
intersection has an acceptable LOS. Delay affects route and mode choice and sometimes
whether a user will decide to complete the trip. A user’s willingness to accept delay depends on
many factors including the user’s knowledge of the transportation network, anticipated traffic
conditions, and alternative options. The increasing presence of in-vehicle guidance systems and
real-time traffic apps further aids the user in selecting the route with shortest travel times. Also,
some alternatives that may improve mobility for one mode, such as the addition of turn lanes,
may result in a performance degradation or even discourage trips for pedestrians or other
modes. Thus, it is important to consider the effects of intersection control on the surrounding
network and for all potential users. The following are some factors when selecting and
evaluating alternatives:
 Access management strategies can be effective in promoting efficient travel patterns
and rerouting traffic to other existing intersections. Check with the WSDOT region
Planning Office for future land use plans or comprehensive plans to provide for future
growth accommodation.
 Consider the volume to capacity (V/C) ratio, the delay, and the queue length of each
approach. Some scenarios may require additional sensitivity analysis to determine the
impacts of small changes in volumes.
 Examine the effects of existing conditions. Consider progression through nearby
intersections (corridor and network analysis) and known risky or illegal driving
maneuvers.
 Consider the possibility that traffic from other intersections with lower LOS will divert
to the new/revised intersection.

1300.05 Procedures
For new intersections: determine and document intersection control according to the
applicable procedures in this chapter.

For existing intersections: An Intersection Control Evaluation (ICE) is required for intersection
improvement projects involving pavement construction and/or reconstruction, or preservation
projects such as signal replacement/rehabilitation. Evaluate intersection control in accordance
with this chapter unless there is documentation that this analysis has already been completed
and is referenced in the Project Summary.

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An ICE is not required, but should be considered, for existing intersections that are unaffected
by the project (per the contributing factors analysis) or are receiving minor revisions such as
signal timing changes or rechannelization of existing pavement. Intersection rechannelization
within existing pavement can result in operational and safety performance changes that should
be evaluated within the existing project framework. Consideration should be given to mainline
traffic volume, entering volume, and availability of mainline gaps for additions of left- or right-
turn storage within existing intersection width.

1300.05(1) Intersection Control Evaluation (ICE)

The Intersection Control Evaluation, formerly known as the Intersection Control Analysis, is a
5-step process meant to screen and evaluate alternatives to determine the best possible
intersection type and design. Scale the ICE according to the size and complexity of the project.
Due to the safety and operational performance record, a roundabout is required to be
evaluated in Step 1.

For each alternative, provide a brief description of the assumed layout. Include the number of
lanes on major and minor approaches and any measures necessary to accommodate multi-
modal users. For a roundabout, document the assumed inscribed circle diameter. For a signal,
document the assumed cycle length and phasing strategy used for the analysis.

Step 1: Background and Project Needs – Describe the existing conditions. Include physical
characteristics of the site, posted speed, AADT, turning movement volumes, channelization and
control features, multimodal facilities, context, and modal priority.

Document the project’s baseline and contextual needs and performance metrics and targets
that will be affected by the intersection. These needs, metrics, and targets will be used for
alternative comparison in Step 3. Identify all project alternatives under consideration. For each
alternative, determine if it is expected to meet the basic needs of the project. Remove
alternatives that do not pass the initial screening, and document their removal. All remaining
alternatives are to proceed to Step 2.

Step 2: Feasibility – Develop the alternatives at a sketch level to determine the footprint
required to achieve performance measures. Consider right-of-way, environmental, cost,
context-sensitive/sustainable design, and geometrics/physical constraints for each remaining
alternative. If an alternative is not practicable from any of these perspectives, remove it from
consideration. For documentation purposes, state why alternatives were removed from further
consideration. All remaining alternatives are to proceed to Step 3.
 Determine the right of way requirements and feasibility. Discuss the right of way
requirements and the feasibility of acquiring that right of way in the analysis. Include
sketches or plan sheets with sufficient detail to identify topography, existing utilities,
environmental constraints, drainage, buildings, and other fixed objects. An economic
evaluation will be useful if additional right of way is needed. Include the right of way
costs in the alternatives evaluation (Step 4).
 Identify known environmental concerns that could influence control type selection. At
this stage, are there any red flags or obvious concerns between potential control
types? Are there any known environmental risks that may substantially increase the
cost of the project or available information that could help in alternatives comparison?
Consult with region Environmental staff for support.

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 Consider Context Sensitive/Sustainable Design. Context sensitive design is a model for

transportation project development. A proposed transportation project is to be
planned not only for its physical aspects as a facility serving specific transportation
objectives for pertinent modes, but also for its effects on the aesthetic, social,
economic, and environmental values, needs, constraints, and opportunities in a larger
community setting. Projects designed using this model:
Optimize safety of the facility for both the user modes and the community.
Promote multimodal solutions.
Are in harmony with the community, and preserve the environmental, scenic,
aesthetic, historic, and natural resource values of the area.
Are designed and built with minimal disruption to the community.
Involve efficient and effective use of the resources (time, budget, community)
of all involved parties.
Minimize maintenance and maximize useful lifetime of the design. See
additional guidance in Chapter 301.

Step 3: Operational and Safety Performance Analysis – Perform and report the results of
applicable analyses for all remaining alternatives and the no-build condition for performance
metrics and targets identified in Step 1. The analysis is scalable, but typically should include the
metrics below. The level of effort should be based on project complexity, cost of proposed
alternatives, context, and impact to the network and other modes. Contact the region Traffic
Office early in the process to determine the network area of influence and scope of analysis.
Include the following:
 Traffic Analysis – Use the opening year and selected design year for analysis (see
Chapter 1103). In some cases, it may also be appropriate to analyze the horizon year as
well. Identify and justify any growth rates used and provide turning movements for all
scenarios. There are several deterministic and microsimulation tools for analyzing delay
and intersection performance. Traffic volumes and the proximity to other access points
will dictate the modeling effort required. Contact the region Traffic Office to determine
the appropriate approved tool(s). For more information and guidance on traffic
analysis, refer to Chapter 320 and the Traffic Analysis webpage
(http://www.wsdot.wa.gov/Design/Traffic/Analysis/).
Peak hour(s) – Report the delay for each alternative.
Off-Peak – Report the delay for an additional time period representative of
off-peak travel. Depending on location, up to 80% of total delay can occur in
off-peak hours.
If a traffic signal is under consideration, perform and report the findings of the
signal warrant analysis.
 Safety Performance Analysis – See the Safety Analysis Guide for ICE safety analysis
procedures.
 Multimodal safety and operations – Briefly discuss how the design for each alternative
is expected to affect applicable multimodal users. Potential items to consider include
pedestrian delay, number of lanes to cross, protected vs permitted turning
movements, motorist approach speed, speed differential of users, etc. When
applicable, evaluate multimodal treatments that may be necessary for each alternative
to meet the performance needs of each user type.

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If a roundabout is determined to be the preferred alternative based on analysis conducted in

Steps 1 through 3, contact the Region Traffic Engineer to determine if further alternative
evaluation is required.

Step 4: Alternatives Evaluation – Compare the alternatives based on their ability to address the
baseline and contextual needs using the established performance metrics and targets. When
applicable, report the Benefit/Cost (B/C) for mobility (due to change in travel time or delay)
and/or the B/C for safety (due to change in crash frequency/severity). The B/C analysis may
include the following:
 Estimated project costs. May use project costs from similar locations of the alternative
as cost justification.
 A qualitative discussion of life cycle cost using the following considerations:
Annual maintenance and operations cost. For signals, this should include the
cost of signal engineers and technicians to review and implement signal
timings and respond to malfunctions and emerging issues. This value can be
obtained from the region Traffic Office.
Travel time savings in all hours of the day.
 Societal cost savings (considered as the Benefit in the analysis) of reduced crash
frequency and/or severity using a predictive method as described in Chapter 321 and
the Safety Analysis Guide. See the Safety Analysis Guide for WSDOT Societal Costs for
crash severities.
 Salvage value of right of way, grading and drainage, and structures.

Step 5: Selection – Based on performance tradeoffs and documented project needs, select the
recommended alternative.

1300.05(1)(a) Additional Information

Discuss the following in the ICE as needed to further support the selection (is it an item that will
have a significant effect on the decision?):
 Review the corridor sketch plans and database with the regional planning office.
 Information from a corridor or planning study.
 Current and future land use and whether or not the intersection control will reasonably
accommodate future land use traffic changes.
 Community engagement and local agency coordination and comments.
 Effect on future local agency projects.
 Other elements considered in the selection of the intersection control.

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1300.05(2) Community Engagement

Community engagement is a necessary element of project development.
Technical, public, and political aspects must be considered. It is critical
that community engagement efforts occur with preparation and well-
organized content regarding the known performance data associated
with different control types to inform communities of the distinct
differences between control types with respect to the existing and future
contexts and modes. Use the baseline and contextual needs (see Chapter
1101) identified by the team and informed by the community to help
support the options being considered to change operational and safety
performance at a given location.

There is often concern from communities regarding control types that may be under
consideration, especially the types of intersections that may seem unfamiliar or that break from
the traditional approach. Education and outreach efforts, if necessary, are collaborative and are
most useful during the analysis and early scoping stages.

Follow the guidelines of WSDOT’s Community Engagement Plan

(www.wsdot.wa.gov/planning/), and document the effort as indicated in Chapter 1100.

1300.05(3) Approval
The ICE shall be prepared by or under the direct supervision of a licensed Professional Engineer.
Approval of the ICE (see Chapter 300 for more information) requires the following:
 Region Traffic Engineer Approval
 HQ Traffic Approval

1300.05(4) Local Agency or Developer-Initiated Intersections

Chapter 320 provides guidance for preparation of a Traffic Impact Analysis (TIA). Early in the
design process, local agencies and developers should coordinate with the region office to
identify specific intersections for further analysis. The project initiator provides an Intersection
Control Evaluation (ICE) for approaches and intersections with state routes per 1300.05, or
references this information in the TIA. The project initiator documents the design considerations
and submits the ICE and all documentation to the region for approval (per 1300.05). After the
ICE is approved, finalize the intersection design and obtain approval per Chapters 300 (for
documentation), 1310 (for intersections), 1320 (for roundabouts), and 1330 (for traffic signals).

1300.06 Documentation
Refer to Chapter 300 for additional design documentation requirements.

1300.07 References

1300.07(1) Federal/State Laws, Codes, and Policies

Revised Code of Washington (RCW) 46.61, Rules of the road

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Washington Administrative Code (WAC) 468-52, Highway access management – access control
classification system and standards

Secretary’s Executive Order: E 1082, Business Practices for Moving Washington, August 2012,
WSDOT

1300.07(2) Design Guidance

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO Current Edition

Highway Capacity Manual (HCM), latest edition, Transportation Research Board, National
Research Council

Local Agency Guidelines (LAG), M 36-63, WSDOT

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

WSDOT Safety Analysis Guide http://www.wsdot.wa.gov/Design/Support.htm

1300.07(3) Supporting Information

Highway Safety Manual (HSM), AASHTO

Roundabouts: An Informational Guide, FHWA-RD-00-067, USDOT, FHWA

Roundabouts: An Informational Guide, Second Edition, NCHRP Report 672, Transportation

Research Board, 2010

A Review of the Signalized Intersections: Informational Guide. FHWA-HRT-04-092, USDOT,

FHWA, APRIL 2004.  www.fhwa.dot.gov/publications/research/safety/04092/

Choosing Intersection Control, IMSA Journal, Buckholz, Nov/Dec 2002.

 www.imsasafety.org/journal/nd02/buckholz.pdf

A Comparison of a Roundabout to Two-way Stop Controlled Intersections with Low and High
Traffic Volumes, Luttrell, Greg, Eugene R. Russell, and Margaret Rys, Kansas State University

Guidance for Implementation of the AASHTO Strategic Highway Safety Plan, Volume 5: A Guide
for Addressing Unsignalized Intersection Collisions, NCHRP Report 500, Transportation Research
Board, 2003

Guidance for Implementation of the AASHTO Strategic Highway Safety Plan Volume 12: A Guide
for Reducing Collisions at Signalized Intersections, NCHRP Report 500, Transportation Research
Board, 2004

U-turn Based Intersections, FHWA

 https://safety.fhwa.dot.gov/intersection/innovative/uturn/

Crossover-Based Intersections, FHWA

 https://safety.fhwa.dot.gov/intersection/innovative/crossover/

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Synthesis of the Median U-Turn Intersection Treatment, Safety, and Operational Benefits,
FHWA-HRT-07-033, USDOT, FHWA

Alternative Intersections/Interchanges: Informational Report (AIIR), FHWA-HRT-09-060, Hughes

et al., USDOT, FHWA, 2010

Field Evaluation of a Restricted Crossing U-Turn Intersection, FHWA-HRT-12-037, USDOT, FHWA

Roundabouts and Sustainable Design, Ariniello et al., Green Streets and Highways – ASCE, 2011

Pedestrian and Bicycle Information Center  www.pedbikeinfo.org/

Community Engagement Plan, WSDOT  http://www.wsdot.wa.gov/planning/default.htm

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Chapter 1310 Intersections
1310.01 General
1310.02 Design Considerations
1310.03 Design Elements
1310.04 Intersection Sight Distance
1310.05 Signing and Delineation
1310.06 Procedures
1310.07 Documentation
1310.08 References

1310.01 General
Intersections are a critical part of Washington State Department of Transportation (WSDOT)
highway design because of increased conflict potential. Traffic and driver characteristics, bicycle
and pedestrian needs, physical features, and economics are considered during the scoping and
design stages to develop channelization and traffic control to provide multimodal traffic flow
through intersections.

See chapters in the 1100 series for instruction on multimodal practical design, including
identifying project needs, context, design controls, modal performance, alternatives analysis,
and design element dimensioning.

This chapter provides guidance for designing intersections, including ramp terminals. Refer to
the following chapters for additional information:

Chapter Subject
1103 Design controls

1106 Design element dimensions

1230 Geometric cross section

1300 Intersection control type

1320 Roundabouts

1330 Traffic signals

1340 Driveways

1360 Interchanges

1510 Pedestrian facilities

1520 Roadway bicycle facilities

For assistance with intersection design, contact the Headquarters (HQ) Design Office.

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1310.02 Design Considerations

Consider all potential users of the facility in the design of an intersection. This involves
addressing the needs of a diverse mix of user groups, including passenger cars, heavy vehicles of
varying classifications, bicycles, and pedestrians. Often, meeting the needs of one user group
results in a compromise in service to others. Intersection design balances these competing
needs, resulting in appropriate levels of operation for all users.

In addition to reducing the number of conflicts, minimize the conflict area as much as possible
while still providing for the design vehicle (see Chapter 1103). This is done to control the speed
of turning vehicles and reduce the area of exposure for vehicles, bicycles, and pedestrians. For
additional information on pedestrian needs, see Chapter 1510. For intersections with shared-
use paths, see Chapter 1515. For bicycle considerations at intersections, see Chapter 1520.

1310.02(1) Non-Geometric Considerations

Geometric design considerations, such as sight distance and intersection angle, are important.
Equally important are perception, contrast, and a driver’s age. Perception is a factor in the
majority of crashes. Regardless of the type of intersection, the function depends on the driver’s
ability to perceive what is happening with respect to the surroundings and other vehicles. When
choosing an acceptable gap, the driver first identifies the approaching vehicle and then
determines its speed. The driver uses visual clues provided by the immediate surroundings in
making these decisions. Thus, given equal sight distance, it may be easier for the driver to judge
a vehicle’s oncoming speed when there are more objects to pass by in the driver’s line of sight.
Contrast allows drivers to discern one object from another.

1310.02(2) Intersection Angle and Roadway Alignment

An important intersection design characteristic is the intersection angle. The desirable
intersection angle is 90°, with 60° to 120° allowed. Do not put angle points on the roadway
alignments within intersection areas or on the through roadway alignment within 100 feet of
the edge of traveled way of a crossroad. However, angle points within the intersection are
allowed at intersections with a minor through movement, such as at a ramp terminal (see
Exhibit 1310-2).

When feasible, locate intersections such that curves do not begin or end within the intersection
area. It is desirable to locate the PC and PT 250 feet or more from the intersection so that a
driver can settle into the curve before the gap in the striping for the intersection area. Do not
locate short curves where both the PC and PT are within the intersection area.

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1310.02(3) Lane Alignment

It is desirable that entering through traffic is
aligned with the exit lanes. However, the entering
and exit lanes may be offset up to 6 feet when the
following conditions are met:
• Illumination is provided.
• The intersection is not within a horizontal
curve, nor is it within a crest vertical
curve.
• The taper rates provided in Exhibit 1310-1
are used.
• There is a posted speed of 55 mph or less.

Consider dotted extension lines that continue

through the intersection.

Exhibit 1310-1 Lane Alignment Taper Rate

6 ft max
offset Posted Speed Taper Rate
allowed
55 mph 55:1
See table for lane
alignment taper rate. 50 mph 50:1
45 mph 45:1
40 mph 27:1
35 mph 21:1
30 mph 15:1
25 mph 11:1

1310.02(4) Intersection Spacing

Provide intersection spacing for efficient operation of the highway. The minimum design
intersection spacing for highways with limited access control is covered in Chapter 530. For
other highways, the minimum design intersection spacing is dependent on the managed access
highway class. (See Chapter 540 for minimum intersection spacing on managed access
highways.)

As a minimum, provide enough space between intersections for left-turn lanes and storage
length. Space signalized intersections and intersections expected to be signalized to maintain
efficient signal operation. Space intersections so that queues will not block an adjacent
intersection.

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Evaluate existing intersections that are spaced less than shown in Chapters 530 and 540. Also,
evaluate closing or restricting movements at intersections with operational issues. Document
the spacing of existing intersections that will remain in place and the effects of the spacing on
operation, capacity, and circulation.

1310.02(5) Accommodating vs. Designing for Vehicles

Accommodating for a vehicle allows encroachment of other lanes, shoulders, or other elements
to complete the required maneuver. Designing for a vehicle does not require encroachment on
those elements.

There are competing design objectives when considering the crossing needs of pedestrians and
the turning needs of larger vehicles. To design for large design vehicles, larger turn radii are
used. This results in increased pavement areas, longer pedestrian crossing distances, and longer
traffic signal arms. (See Chapter 1103 for design vehicle selection criteria.)

When appropriate, to reduce the intersection area, consider accommodating for large vehicles
instead of designing for them. This reduces the potential for vehicle/pedestrian conflicts,
decreases pedestrian crossing distance, and controls the speeds of turning vehicles. Use turn
simulation software (such as AutoTURN®) to verify the design.

1310.02(6) Sight Distance

For stopping and decision sight distance criteria, see Chapter 1260. Intersection sight distance
criteria are discussed in section 1310.05.

1310.02(7) Crossroads
When the crossroad is a city street or county road, design the crossroad beyond the intersection
area in cooperation with the local agency.
When the crossroad is a state facility, design the crossroad according to the Design Manual.
Continue the cross slope of the through roadway shoulder as the grade for the crossroad. Use a
vertical curve that is at least 60 feet long to connect to the grade of the crossroad.
Evaluate the profile of the crossroad in the intersection area. The crown slope of the main line
might need to be adjusted in the intersection area to improve the profile for the cross traffic.
Design the grade at the crosswalk to meet the requirements for accessibility. (See Chapter 1510
for additional crosswalk information.)
In areas that experience accumulations of snow and ice for all legs that require traffic to stop,
design a maximum grade of ±4% for a length equal to the anticipated queue length for stopped
vehicles.

1310.02(8) Rural Expressway At-Grade Intersections

Evaluate grade separations at all intersections on rural expressways.
Design high-speed at-grade intersections on rural expressways as indirect left turns, split
intersections, or roundabouts.
The State Traffic Engineer’s approval is required for any new intersection or signal on a rural
expressway.

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Chapter 1310 Intersections

1310.02(9) Interchange Ramp Terminals

When stop control or traffic signal control is selected, the design to be used or modified is
shown in Exhibit 1310-2. Higher-volume intersections with multiple ramp lanes are designed
individually. Provide ramp terminal designs consistent with the speed of the crossroad.

Where stop control or signal control is implemented, the intersection configuration criteria for
ramp terminals are normally the same as for other intersections. One exception is that an angle
point is allowed between an off-ramp and an on-ramp. This is because the through movement
of traffic getting off the freeway, going through the intersection, and getting back on the
freeway is minor.

Another exception is at ramp terminals where the through movement is eliminated (for
example, at a single-point interchange). For ramp terminals that have two wye connections, one
for right turns and the other for left turns, and no through movement, the intersection angle has
little meaning and does not need to be considered.

Due to the probable development of large traffic generators adjacent to an interchange, width
for a median on the local road is desirable whenever such development is expected. This allows
for future left-turn channelization. Use median channelization when justified by capacity
determination and analysis or by the need to provide a smooth traffic flow.

Adjust the alignment of the intersection legs to fit the traffic movements and to discourage
wrong-way movements. Use the allowed intersecting angles of 60° to 120° in designing the best
alignment for efficiency and intersection operations.

Exhibit 1310-2 Ramp Terminal Intersection Details

[1]

60º-120º

Angular corners to
discourage wrong- CL ramp Taper Rates [3]
way right turns.

R=50 ft min [2]

Notes:
[1] For right-turn corner design, see Exhibit 1310-6.
[2] Use turn simulation software to verify that the design vehicle can make the turn.
[3] For taper rates, see Exhibit 1310-10a, Table 1.

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1310.02(10) Wrong-Way Movement Countermeasures

Wrong-way crashes, though infrequent, have the potential to be more serious than other types
of crashes, especially on high-speed facilities. Crash data show that impaired and older drivers
are overrepresented and that a high percentage of these occurrences are at night. Washington
State data show approximately equal numbers of crashes on the Interstate and multilane urban
principal arterial highways. Discourage wrong-way maneuvers at all stages of design.

1310.02(10)(a) Wrong-Way Driving Countermeasure Categories

There are three categories of countermeasures to discourage wrong-way driving:
• Signing and delineation
• Intelligent transportation systems
• Geometric design
1310.02(10)(a)(1) Signing and Delineation

Signing and delineation countermeasures include:

• DO NOT ENTER and WRONG WAY signs.
• ONE WAY signs.
• Turn restriction signs.
• Red-backed raised pavement markers (RPMs).
• Directional pavement arrows.
• Yellow edge line on left and white edge line on right side of exit ramps.
• Pavement marking extension lines to direct drivers to the correct ramp.

Signing can be a more effective countermeasure when the signs are lowered. At night,
lowered signs are better illuminated by low-beam headlights. Other improvements may
include a second set of signs, supplemental sign placards, oversized signs, flashing beacons,
internal illumination, overhead-mounted signs, red reflective tape on the back of signs,
extra overhead lighting, and red-backed guideposts on each side of the ramp up to the
WRONG WAY sign.
1310.02(10)(a)(2) Intelligent Transportation Systems (ITS)

Wrong-way ITS countermeasures are wrong-way detection and warning systems. Contact
the region Traffic Office for assistance when considering an ITS wrong-way warning system.
1310.02(10)(a)(3) Geometric Design

Geometric countermeasures include separating wrong-way movements from other

movements, discouraging wrong-way movements, encouraging right-way movements, and
improving the visibility of the right-way movement.
a. Separate On- and Off-Ramp Terminals

Consider the separation of on- and off-ramp terminals, particularly at interchanges where
the ramp terminals are closely spaced (for example, partial cloverleaf ramps combined with
other ramps). Wider medians between off- and on-ramp terminals provide room for signing
and allow the median end to be shaped to help direct vehicles onto the correct roadway.
The minimum width of the raised median is 7 feet, face of curb to face of curb, to
accommodate a 36 inch sign.

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Extend the raised median on a two-way ramp from the ramp terminal intersection to the
split of the on- and off-ramps. The median outside of the intersection area may be reduced
to the width of a dual-faced mountable curb. (See Exhibit 1310-3 for an example of the
minimum median at the terminal of a two-way ramp.)

Exhibit 1310-3 Median at Two-Way Ramp Terminal

See Chapters 1230 and

1360 for median widths Mountable curb

Raised median

Minimum raised
median width is
sign width plus 4 ft
Pavement marking
extensions
(see the MUTCD)

b. Reduced Off-Ramp Terminal Throat Width

Reducing the width of the off-ramp throat has been a successful method of discouraging
wrong-way movements. A smaller opening makes the wrong-way entry less inviting,
particularly for closely spaced ramps. When off-ramp terminals have right-turn lanes, a
raised island will reduce the potential for a wrong-way movement.

c. Increased On-Ramp Terminal Throat Width

Increasing the width of the on-ramp throat can encourage right-way movements. A larger
opening for the on-ramp makes it easier to turn into. To increase the throat width of on-
ramps, use flat radii for left- and right-turning traffic and remove islands.

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d. Intersection Balance

When drivers make a left turn, they are required to leave the intersection in the extreme
left-hand lane lawfully available. As a result, left-turning drivers tend to head for a point
between 50% and 60% of the way through the intersection.

At a two-way ramp terminal, the desirable throat width for the on-ramp roadway is not less
than the off-ramp roadway width to accommodate this behavior (see Exhibit 1310-4). Much
of this can be achieved by adjusting the stop bar position on the interchange cross street.

Exhibit 1310-4 Intersection Balance Example

When practicable, do not

When practicable, provide island at on-ramp
provide island at off- to increase throat width.
ramp to reduce width.

60% L max

e. Visibility

When drivers can see and recognize the roadway they want to turn onto, they are less likely
to make a mistake and turn onto the wrong roadway. For two-way ramps and divided
multilane roadways with barrier in the median, end the barrier far enough from the
intersection that a left-turning driver can see and recognize the roadway going the correct
direction. Drivers need to see the delineation pavement markings, curbs, or other elements
to locate the correct roadway.

f. Angular Corners on the Left of Off-Ramp Terminals

Angular corners on the left side of off-ramp terminals will discourage wrong-way right turns.
Provide a corner design as angular as feasible that will provide for the left turn from the off-

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ramp. Circular curves can look inviting for a wrong-way right turn onto the off-ramp (see
Exhibit 1310-2).
1310.02(10)(b) Countermeasure Applications
Following are applications of wrong-way countermeasures for some common locations. For
assistance with signing and delineation, contact the region Traffic Office.
1310.02(10)(b)(1) All Ramps

Countermeasures that can be used on almost any ramp or intersection with potential
wrong-way concerns include:
• Enlarged warning signs.
• Directional pavement arrows at ramp terminals.
• Redundant signing and pavement arrows.
• Roundabout ramp terminal intersections, where room is available.
• Red-backed RPMs.
1310.02(10)(b)(2) One-Way Diamond Off-Ramp

Diamond interchanges are common, and although drivers are familiar with them, they can
still get confused and go the wrong way. In addition to signing and pavement markings for
these interchanges, provide:
• Angular corners to discourage wrong-way right turns.
1310.02(10)(b)(3) Diamond Interchange With Advance Storage

Diamond interchanges with advance storage have left-turn storage lanes that extend from
the on-ramp past the off-ramp (see Exhibit 1310-5). This allows for a potential early left turn
onto the off-ramp. Following are additional countermeasures for interchanges with
advanced left-turn storage:
• Provide a raised median to discourage the wrong-way left turn.
• Provide signing and directional arrows to direct traffic to the correct left-turn
point.

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Exhibit 1310-5 Diamond Interchange with Advance Storage

Provide raised
median island.

Extend raised median island

into intersection to discourage
Raised sidewalk with angular wrong-way left turn.
corners to discourage wrong-
way right turns.

1310.02(10)(b)(4) Two-Way Ramps

Two-way ramps have the on- and off-ramp adjacent to each other. They are used at partial
cloverleaf, trumpet, and button hook interchanges. Because the on and off roadways are
close to each other, they are more vulnerable to wrong-way driving. Also, when the
separation between on and off traffic is striping only, the ramps are susceptible to drivers
entering the correct roadway and inadvertently crossing to the wrong ramp. In addition to
signing and delineation, the following are countermeasures for two-way ramps:
• Separate the on- and off-ramp terminals.
• Reduce off-ramp terminal throat width.
• Increase on-ramp terminal throat width.
• Maintain intersection balance.
• Improve on-ramp visibility.
• Provide a raised median or dual-faced curb from the ramp terminal
intersection to the gore nose.
1310.02(10)(b)(5) HOV Direct Access Ramps

HOV direct access ramps are two-way ramps in the median; therefore, the ability to provide
separation between the on and off traffic is limited by the width of the median. An
additional concern is that HOV direct access ramps are left-side ramps. Drivers normally
enter the freeway using a right-side ramp and they may mistakenly travel the wrong way on
a left-side ramp. Review existing and proposed signing for inadvertent misdirection. (See
Chapter 1420 for HOV direct access and countermeasures for wrong-way driving at HOV
direct access ramps.)

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1310.02(10)(b)(6) Multilane Divided Roadways

Wrong-way driving can also occur on multilane divided nonfreeway facilities. Wrong-way
drivers may enter multilane divided facilities at driveways and at-grade intersections.
Countermeasures for wrong-way driving on nonfreeway multilane divided highways include:
• Wrong-way signing and delineation at the intersections.
• Right-in/right-out road approaches.

1310.03 Design Elements

When designing an intersection, identify and address the needs of all intersection users.

If pedestrian facilities are present, the design objective becomes one of reducing the potential
for vehicle/pedestrian conflicts. This is done by minimizing pedestrian crossing distances and
controlling the speeds of turning vehicles. Pedestrian refuge islands can be beneficial. They
minimize the pedestrian crossing distance, reduce the conflict area, and minimize the impacts
on vehicular traffic. When designing islands, speeds can be reduced by designing the turning
roadway with a taper or large radius curve at the beginning of the turn and a small radius curve
at the end. This allows larger islands while forcing the turning traffic to slow down. Use turn
simulation software (such as AutoTURN®) to verify the design.

Channelization, the separation or regulation of traffic movements into delineated paths of

travel, can facilitate the orderly movement of pedestrians, bicycles, and vehicles. Channelization
includes left-turn lanes, right-turn lanes, speed change lanes (both acceleration and deceleration
lanes), and islands.

1310.03(1) Right-Turn Corners

Exhibit 1310-6 shows initial ranges for right-turn corner designs using a simple curve with a
taper. These are considered approximate pavement areas to accommodate the design vehicles
without encroachment on the adjacent lane at either leg of the curve.

Depending on the context of the roadway and right-turn corner (and whether the right-turn
corner will be designed for or will accommodate a design vehicle), there may be several design
considerations. Consider vehicle-pedestrian conflicts; vehicle encroachment on the shoulder or
adjacent same-direction lane at the exit leg; capacity restrictions for right-turning vehicles or
other degradation of intersection operations; and the effects on other traffic movements.

Other design considerations may include a combination of simple or compound curves, tapers at
the beginning or end of the turn, and so on. Verify the design vehicle can make the turn using
turn simulation software (such as AutoTURN®).

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Exhibit 1310-6 Initial Ranges for Right-Turn Corner (Simple Curve-Taper)

L1 A L1 = Available roadway width [2]

that the vehicle is turning from
L2
L2 = Available roadway width [2] for the
R vehicle leaving the intersection
1 R = Radius to the edge of traveled way
T T = Taper rate (length per unit of width
of widening)
A = Delta angle of the turning vehicle

Vehicle A R L1 [1] L2 [2] T

P All 30 11 11 25
SU-30 &
All 50 11 11 25
CITY-BUS
WB-40 All 55 11 15 7.5
WB-67 All 50-85 11 22-24 7
Notes:
[1] When available roadway width is less than 11 ft, widen at 25:1.
[2] Available roadway width includes the shoulder, less a 2-ft clearance to a curb, and all the same-
direction lanes of the exit leg at signalized intersections.
General:

All distances given in feet and angles in degrees

1310.03(2) Left-Turn Lanes and Turn Radii

Left-turn lanes provide storage, separate from the through lanes, for left-turning vehicles
waiting for a signal to change or for a gap in opposing traffic. (See 1310.03(4) for a discussion on
speed change lanes.)

Design left-turn channelization to provide sufficient operational flexibility to function under

peak loads and adverse conditions.

1310.03(2)(a) One-Way Left-Turn Lanes

One-way left-turn lanes are separate storage lanes for vehicles turning left from one roadway
onto another. One-way left-turn lanes may be an economical way to lessen delays and crash
potential involving left-turning vehicles. In addition, they can allow deceleration clear of the

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through traffic lanes. Provide a minimum storage length of 100 feet for one-way left-turn lanes.
When evaluating left-turn lanes, include impacts to all intersection movements and users.

At signalized intersections, use a traffic signal analysis to determine whether a left-turn lane is
needed and the storage length. If the length determined is less than the 100-foot minimum,
make it 100 feet (see Chapter 1330).

At unsignalized intersections, use the following as a guide to determine whether or not to

provide one-way left-turn lanes:
• A traffic analysis indicates congestion reduction with a left-turn lane. On two-lane
highways, use Exhibit 1310-7a, based on total traffic volume (DHV) for both
directions and percent left- turn traffic, to determine whether further investigation
is needed. On four-lane highways, use Exhibit 1310-7b to determine whether a left-
turn lane is recommended.
• A study indicates crash reduction with a left-turn lane.
• Restrictive geometrics require left-turning vehicles to slow greatly below the speed
of the through traffic.
• There is less than decision sight distance for traffic approaching a vehicle stopped at
the intersection to make a left turn.

A traffic analysis based on the Highway Capacity Manual (HCM) may also be used to determine
whether left-turn lanes are needed to maintain the desired level of service.

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Exhibit 1310-7a Left-Turn Storage Guidelines: Two-Lane, Unsignalized

KEY: 1 Below curve, storage not needed for capacity.

1,100 2 Above curve, further analysis recommended.

* DHV is total volume from both directions

1,000 **Speeds are posted speeds

900

800
Total DHV*

700
2
1

600

2
1
40 m
500 ph*
*
2
1 50 m
ph**

400
60 mp
h* *

300
0 5 10 15 20 25

% Total DHV Turning Left (single turning movement)

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Exhibit 1310-7b Left-Turn Storage Guidelines: Four-Lane, Unsignalized

S= Left-turn storage length

1,800

1,600

1,400
Opposing Through Volume (DDHV)

1,200

1,000

800

600
S=
Storage not needed

30
0f
400 t
S=

S=

S=
S=

20

25
10

15

0
0
0f

ft
ft
ft
t

200

0
0 50 100 150 200 250 300 350 400 450 500
Left-Turning Volume (DHV)

Determine the storage length on two-lane highways by using Exhibits 1310-8a through 8c. On
four-lane highways, use Exhibit 1310-7b. These lengths do not consider trucks. Use Exhibit
1310-9 for storage length when trucks are present.

Use turn simulation software (such as AutoTURN®) to verify that left-turn movements for the
design vehicle(s) do not have conflicts. Design opposing left-turn design vehicle paths with a
minimum 4-foot (12-foot desirable) clearance between opposing turning paths.

Where one-way left-turn channelization with curbing is to be provided, evaluate surface water
runoff and design additional drainage facilities if needed to control the runoff.

Provide illumination at left-turn lanes in accordance with the guidelines in Chapter 1040.

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Exhibit 1310-8a Left-Turn Storage Length: Two-Lane, Unsignalized (40mph)

40 mph Posted Speed

1400

1300 250 ft

1200

200 ft
DHV (Total, Both Directions)

1100

1000

900

150 ft

800

700 100 ft

600
0 100 200 300

Hourly Left Turns in One Direction

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Exhibit 1310-8b Left-Turn Storage Length: Two-Lane, Unsignalized (50 mph)

50 mph Posted Speed

1400

1300
250 ft

1200
DHV (Total, Both Directions)

1100

200 ft
1000

900

800
150 ft

700

100 ft
600

500
0 100 200 300

Hourly Left Turns in One Direction

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Exhibit 1310-8c Left-Turn Storage Length: Two-Lane, Unsignalized (60 mph)

60 mph Posted Speed

1400

1300

250 ft

1200
DHV (Total, Both Directions)

1100

200 ft
1000

900

800
150 ft

700

100 ft
600

500
0 100 200 300

Hourly Left Turns in One Direction

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Exhibit 1310-9 Left-Turn Storage with Trucks (ft)

% Trucks in Left-Turn Movement

Storage Length* (ft)
10 20 30 40 50

100 125 125 150 150 150

150 175 200 200 200 200
200 225 250 275 300 300
250 275 300 325 350 375
300 350 375 400 400 400
*Length from Exhibits 1310-7b and 1310-8a, 8b, or 8c.

At signalized intersections with high left-turn volumes, double (or triple) left-turn lanes may be
needed to maintain the desired level of service. For a double left-turn, a throat width of 30 to 36
feet is desirable on the exit leg of the turn to offset vehicle offtracking and the difficulty of two
vehicles turning abreast. Use turn simulation software (such as AutoTURN®) to verify that the
design vehicle can complete the turn. Where the design vehicle is a WB 40 or larger, it is
desirable to provide for the design vehicle in the outside lane and an SU-30 vehicle turning
abreast rather than two design vehicles turning abreast.

Exhibits 1310-10a through 10f show left-turn lane geometrics, which are described as follows:
1310.03(2)(a)(1) Widening

It is desirable that offsets and pavement widening (see Exhibit 1310-10a) be symmetrical
about the centerline or baseline. Where right of way or topographic restrictions, crossroad
alignments, or other circumstances preclude symmetrical widening, pavement widening
may be on one side only.
1310.03(2)(a)(2) Divided Highways

Widening is not needed for left-turn lane channelization where medians are 11 feet wide or
wider (see Exhibits 1310-10b through 10d). For medians between 13 feet and 23 feet or
where the acceleration lane is not provided, it is desirable to design the left-turn lane
adjacent to the opposing lane (see Exhibit 1310-10b) to improve sight distance and increase
opposing left-turn clearances.

A median acceleration lane (see Exhibits 1310-10c and 10d) may be provided where the
median is 23 feet or wider. The median acceleration lane might not be needed at a
signalized intersection. When a median acceleration lane is to be used, design it in
accordance with 1310.03(4), Speed Change Lanes. Where medians have sufficient width,
provide a 2-foot shoulder adjacent to a left-turn lane.
1310.03(2)(a)(3) Minimum Protected Left Turn With a Median

At intersections on divided highways where channelized left-turn lanes are not provided,
provide the minimum protected storage area (see Exhibit 1310-10e).

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1310.03(2)(a)(4) Modifications to Left-Turn Designs

The left-turn lane designs discussed above and given in Exhibits 1310-10a through 10e may
be modified when determined by design element dimensioning (see Chapter 1106.)
Document the benefits and impacts of the modified design, including changes to vehicle-
pedestrian conflicts; vehicle encroachment; deceleration length; capacity restrictions for
turning vehicles or other degradation of intersection operations; and the effects on other
traffic movements. Provide a modified design that is able to accommodate the design
vehicle, and provide for the striping (see the Standard Plans and the MUTCD). Verify the
design vehicle can make the turn using turn simulation software (such as AutoTURN®);
include a plot of the design and verification.

Exhibit 1310-10a Median Channelization: Widening

Left-turn storage
100 ft min [2] 50 ft
Taper length = T1 X taper rate [5]
T1[1][7]

T2 [1][7]

[3] Taper length = T2 X taper rate [5]

[4]
Notes:
[1] The minimum width of the left-turn storage T1 = Width of left-turn lane on approach side of
lane (T1+T2) is 11 ft. centerline
[2] For left-turn storage length, see Exhibits T2 = Width of left-turn lane on departure side of
1310-7b for 4-lane roadways or 1310-8a centerline
through 8c for 2-lane roadways.
[3] Use turn simulation software (such as Desirable
AutoTURN®) to verify the design vehicle can Posted Speed
Taper Rate [6]
make the turn.
[4] For right-turn corner design, see Exhibit 55 mph 55:1
1310-6.
50 mph 50:1
[5] For desirable taper rates, see Table on this
Exhibit. With justification, taper rates from 45 mph 45:1
the Table in Exhibit 1310-10c may be used.
[6] For pavement marking details, see the 40 mph 40:1
Standard Plans and the MUTCD.
35 mph 35:1
[7] Where curb is provided, add the width of the
curb and the shoulders to the left-turn lane 30 mph 30:1
width. For shoulder widths at curbs, see
1310.03(6) and Chapter 1230. 25 mph 25:1

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Exhibit 1310-10b Median Channelization: Median Width 11 ft or More

Deceleration taper Alternate design

4
1

Deceleration
100 ft min 50 ft taper [6]
Left-turn storage [2]
15
1

[1] 13 ft [7]
[5]
[3]

[4]

Notes:
[1] Where curb is provided, add the width of the curb and the shoulders. For shoulder widths
at curbs, see 1310.03(6) and Chapter 1230.
[2] For left-turn storage length, see Exhibits 1310-7b for 4-lane roadways or 1310-8a through 8c for
2-lane roadways.
[3] Verify the design vehicle can make the turn using turn simulation software (such as AutoTURN®).
[4] For right-turn corner design, see Exhibit 1310-6.
[5] For median widths greater than 13 ft, it is desirable to locate the left-turn lane adjacent to the
opposing through lane with excess median width between the same-direction through lane and the
turn lane.
[6] For increased storage capacity, the left-turn deceleration taper alternate design may be used.
[7] Reduce to lane width for medians less than 13 ft wide.

General:
For pavement marking details, see the Standard Plans and the MUTCD.

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Exhibit 1310-10c Median Channelization: Median Width 23 ft to 26 ft

Deceleration taper Alternate design

4
1

100 ft min 50 ft Deceleration

taper [7]
Left-turn storage [2]

15
1
11 ft min [1]
12 ft min

Acceleration length [5] Acceleration taper [6]

Not less than 600 ft desirable (300 ft min)
[3]
[4]
Notes:
[1] When curb is provided, add the width of the curb.
[2] For left-turn storage length, see Exhibits 1310 7b
for 4-lane roadways or 1310-8a through 8c for 2-lane roadways.
[3] Verify the design vehicle can make the turn using turn simulation software (such as AutoTURN®).
[4] For right-turn corner design, see Exhibit 1310 6.
[5] The minimum total length of the median acceleration
lane is shown in Exhibit 1310-14.
Posted Speed Taper Rate
[6] For acceleration taper rate, see Table on this exhibit.
[7] For increased storage capacity, the left-turn 55 mph 55:1
deceleration taper alternate design may be used.
50 mph 50:1
General:
45 mph 45:1
For pavement marking details, see the Standard Plans and
the MUTCD. 40 mph 27:1
35 mph 21:1
30 mph 15:1
25 mph 11:1

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Exhibit 1310-10d Median Channelization: Median Width of More Than 26 ft

Notes:
[1] For left-turn storage length, see Exhibits 1310-7b for 4-lane roadways or 1310-8a through 8c for 2
lane roadways.
[2] Verify the design vehicle can make the turn using turn simulation software (such as AutoTURN®).
[3] For right-turn corner design, see Exhibit 1310-6.
[4] The minimum length of the median acceleration lane is shown in Exhibit 1310-14.
[5] For acceleration taper rate, see the Table on Exhibit 1310-10c.
[6] The desirable length of the left-turn deceleration lane including taper is shown in Exhibit 1310-13.

General:
For pavement marking details, see the Standard Plans and the MUTCD.

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Exhibit 1310-10e Median Channelization: Minimum Protected Storage

15 ft min
15
1
[3]

2 ft min

[2]

[1]

Notes:
[1] Verify the design vehicle can make the turn using turn simulation software (such as AutoTURN®).
[2] For right-turn corner design, see Exhibit 1310-6.
[3] For median width 17 ft or more. For median width less than 17 ft, widen to 17 ft. or use Exhibit 1310-
10b.
General:
For pavement marking details, see the Standard Plans and the MUTCD.

1310.03(2)(b) Two-Way Left-Turn Lanes (TWLTL)

Two-way left-turn lanes are located between opposing lanes of traffic. They are used by vehicles
making left turns from either direction, from or onto the roadway.

Use TWLTLs only on managed access highways where there are no more than two through lanes
in each direction. Evaluate installation of TWLTLs where:
• A crash study indicates reduced crashes with a TWLTL.
• There are existing closely spaced access points or minor street intersections.
• There are unacceptable through traffic delays or capacity reductions because of left-
turning vehicles.

TWLTLs can reduce delays to through traffic, reduce rear-end crashes, and provide separation
between opposing lanes of traffic. However, they do not provide refuge for pedestrians and can
encourage strip development with additional closely spaced access points. Evaluate other
alternatives (such as prohibiting midblock left turns and providing for U-turns) before using a
TWLTL. (See Chapter 540 for additional restrictions on the use of TWLTLs, and Chapter 1230 for
discussion of road diets, which commonly employ a center turn lane.)

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The basic design for a TWLTL is illustrated in Exhibit 1310-10f. Additional criteria are as follows:
• The desirable length of a TWLTL is not less than 250 feet.
• Provide illumination in accordance with the guidelines in Chapter 1040.
• Pavement markings, signs, and other traffic control devices must be in accordance
with the MUTCD and the Standard Plans.
• Provide clear channelization when changing from TWLTLs to one-way left-turn lanes
at an intersection.

Exhibit 1310-10f Median Channelization: Two-Way Left-Turn Lane

Major
cross street

100 ft min
Left-turn storage

Match line
[1] 13 ft desirable
11 ft min
[2]
Posted speed < 50 mph = 390 ft min
Posted speed ≥ 50 mph = 420 ft min
Match line

Minor
cross street

Notes:
[1] Verify the design vehicle can make the turn using turn simulation software (such as AutoTURN®).
[2] For right-turn corner design, see Exhibit 1310-6.
General:
For pavement marking details and signing criteria, see the Standard Plans and the MUTCD.

1310.03(3) Right-Turn Lanes

Right-turn movements influence intersection capacity even though there is no conflict between
right-turning vehicles and opposing traffic. Right-turn lanes might be needed to maintain
efficient intersection operation. Use the following to determine when to consider right-turn
lanes at unsignalized intersections:
• For two-lane roadways and for multilane roadways with a posted speed of 45 mph or
above, when recommended by Exhibit 1310-11.

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• A crash study indicates an overall crash reduction with a right-turn lane.

• The presence of pedestrians requires right-turning vehicles to stop.
• Restrictive geometrics require right-turning vehicles to slow greatly below the speed
of the through traffic.
• There is less than decision sight distance for traffic approaching the intersection.
• For unsignalized intersections, see 1310.03(4) for guidance on right-turn lane lengths.
For signalized intersections, use a traffic signal analysis to determine whether a right-
turn lane is needed and what the length is (see Chapter 1330).
• A capacity analysis may be used to determine whether right-turn lanes are needed to
maintain the desired level of service.
• Where adequate right of way exists, providing right-turn lanes is relatively
inexpensive and can provide increased operational efficiency.
• The right-turn pocket or the right-turn taper (see Exhibit 1310-12) may be used at
any minor intersection where a right-turn lane is not provided. These designs reduce
interference and delay to the through movement by offering an earlier exit to right-
turning vehicles.
• If the right-turn pocket is used, Exhibit 1310-12 shows taper lengths for various
posted speeds.

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Exhibit 1310-11 Right-Turn Lane Guidelines

100

Consider right-turn lane [5]

80
Peak Hour Right-Turn Volume [2]

Consider right-turn
pocket or taper [4]

60

40

Radius only [3]

20

0
0 100 200 300 400 500 600 700
Peak Hour Approach Volume (DDHV) [1]
Notes:
[1] For two-lane highways, use the peak hour DDHV (through + right-turn).
For multilane, high-speed highways (posted speed 45 mph or above), use the right-lane peak
hour approach volume (through + right-turn).
[2] When all three of the following conditions are met, reduce the right-turn DDHV by 20:
• The posted speed is 45 mph or below
• The right-turn volume is greater than 40 VPH
• The peak hour approach volume (DDHV) is less than 300 VPH
[3] For right-turn corner design, see Exhibit 1310-6.
[4] For right-turn pocket or taper design, see Exhibit 1310-12.
[5] For right-turn lane design, see Exhibit 1310-13.

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Exhibit 1310-12 Right-Turn Pocket and Right-Turn Taper

11 ft min

L (see table) 60 ft min

Right-Turn Pocket
See Exhibit
1310-6 for right-
turn corner
design
100 ft

13 ft

Right-Turn Taper

Posted Speed Limit L

Below 40 mph 40 ft

40 mph or above 100 ft

1310.03(4) Speed Change Lanes

A speed change lane is an auxiliary lane primarily for the acceleration or deceleration of vehicles
entering or leaving the through traveled way. Speed change lanes are normally provided for at-
grade intersections on multilane divided highways with access control. Where roadside
conditions and right of way allow, speed change lanes may be provided on other through
roadways. Justification for a speed change lane depends on many factors, including speed;
traffic volumes; capacity; type of highway; design and frequency of intersections and crash
history

When either deceleration or acceleration lanes are to be used, design them in accordance with
Exhibits 1310-13 and 1310-14. When the design speed of the turning traffic is greater than
20 mph, design the speed change lane as a ramp in accordance with Chapter 1360. When a
deceleration lane is used with a left-turn lane, add the deceleration length to the storage length.

A dedicated deceleration lane (see Exhibit 1310-13) is advantageous because it removes slowing
vehicles from the through lane.

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An acceleration lane (see Exhibit 1310-14) is not as advantageous because entering drivers can
wait for an opportunity to merge without disrupting through traffic. However, acceleration lanes
for left-turning vehicles provide a benefit by allowing the turn to be made in two movements.

Exhibit 1310-13 Right-Turn Lane

Highway Design Deceleration Lane Posted Speed Limit L

Speed (mph) Length (ft)
Below 40 mph 40 ft
30 160 [1]
40 mph or above 100 ft
35 220
40 275
45 350
50 425 Grade Upgrade Downgrade

55 515 3% to less
0.9 1.2
than 5%
60 605
5% or more 0.8 1.35
65 715
70 820 Adjustment Multiplier for Grades
3% or Greater
Minimum Deceleration Lane Length (ft)
Notes:
[1] When adjusting for grade, do not reduce the deceleration lane to less than 150 ft.
[2] For right-turn corner design, see Exhibit 1310-6.
[3] See 1310.03(6) and Chapter 1230.

General:
For pavement marking details, see the Standard Plans and the MUTCD.

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Exhibit 1310-14 Acceleration Lane

Acceleration length (see table) [1] 300 ft min

[4]

Taper not steeper

Design shoulder width [3]
than 25:1
[2]

Highway Turning Roadway

Design Speed Design Speed (mph)
Highway
(mph) Stop 15 20 Design
% Grade Upgrade Downgrade
Speed
30 180 140
(mph)
35 280 220 160
40 1.3 0.7
40 360 300 270 3% to
50 1.3 0.65
less than
45 560 490 440 60 1.4 0.6
5%
70 1.5 0.6
50 720 660 610
40 1.5 0.6
55 960 900 810 50 5% or 1.5 0.55
60 1,200 1,140 1,100 60 more 1.7 0.5
70 2.0 0.5
65 1,410 1,350 1,310
Adjustment Multiplier for Grades
70 1,620 1,560 1,520
3% or Greater
Minimum Acceleration Length (ft) [1]

Notes:

[1] At free right turns (no stop required) and all left turns, the minimum acceleration lane length is
not less than 300 ft.

[2] For right-turn corner design, see Exhibit 1310-6.

[3] See 1310.03(6) and Chapter 1230.

[4] Lane width as determined by Chapters 1106 and 1230.

General:
For pavement-marking details, see the Standard Plans and the MUTCD.

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1310.03(5) Drop Lanes

A lane may be dropped at an intersection with a turn-only lane or beyond the intersection. Do
not allow a lane-reduction taper to cross an intersection or end less than 100 feet before an
intersection. (See Chapter 1210 for lane reduction pavement transitions.)

When a lane is dropped beyond signalized intersections, provide a lane of sufficient length to
allow smooth merging. For facilities with a posted speed of 45 mph or higher, use a minimum
length of 1,500 feet. For facilities with a posted speed lower than 45 mph, provide a lane of
sufficient length that the advanced lane reduction warning sign can be placed not less than 100
feet beyond the intersection area.

When a lane is dropped beyond unsignalized intersections, provide a lane beyond the
intersection not less than the acceleration lane length from Exhibit 1310-14.

1310.03(6) Shoulders
Shoulder width is controlled by its intended functional use and its contribution to achieving the
desired safety performance when balanced with other design elements. See Exhibit 1239-2 for
functional uses and recommended shoulder widths.

Reducing the shoulder width at intersections facilitates the installation of turn lanes without
unduly affecting the overall width of the roadway. A narrower roadway also reduces pedestrian
exposure in crosswalks and discourages motorists from using the shoulder to bypass other
turning traffic.

1310.03(7) Islands
An island is a defined area within an intersection between traffic lanes for the separation of
vehicle movements or for pedestrian refuge. Within an intersection, a median is considered an
island. Design islands to clearly delineate the traffic channels to drivers and pedestrians.

Traffic islands perform the following functions:

• Channelization islands control and direct traffic movements.
• Divisional islands separate traffic movements.
• Refuge islands provide refuge for pedestrians and bicyclists crossing the roadway.
• Islands can provide for the placement of traffic control devices and luminaires.
• Islands can provide areas within the roadway for landscaping.

1310.03(7)(a) Size and Shape

Divisional islands are normally elongated and at least 4 feet wide and 20 feet long.

Channelization islands are normally triangular. In rural areas, 75 ft2 is the minimum island area
and 100 ft2 is desirable. In urban areas where posted speeds are 25 mph or below, smaller
islands are acceptable. Use islands with at least 200 ft2 if pedestrians will be crossing or traffic
control devices or luminaires will be installed.

Design triangular-shaped islands as shown in Exhibits 1310-15a through 15c. The shoulder and
offset widths illustrated are for islands with vertical curbs 6 inches or higher. Where painted
islands are used, such as in rural areas, these widths are desirable but may be omitted. (See
Chapter 1240 for desirable turning roadway widths.)

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Island markings may be supplemented with reflective raised pavement markers.

Provide barrier-free access at crosswalk locations where raised islands are used. For pedestrian
refuge islands and barrier-free access requirements, see Chapter 1510.
1310.03(7)(b) Location
Design the approach ends of islands so they are visible to motorists. Position the island so that a
smooth transition in vehicle speed and direction is attained. Begin transverse lane shifts far
enough in advance of the intersection to allow gradual transitions. Avoid introducing islands on
a horizontal or vertical curve. If the use of an island on a curve cannot be avoided, provide sight
distance, illumination, or extension of the island.

Exhibit 1310-15a Traffic Island Designs

Widen shoulder for

Widen shoulder for truck turning path [1][2]
truck turning path [1][2]
R=55 ft min
[3]
Edge of shoulder
R=55 ft min

Edge of 100 ft deceleration taper

(desirable)
shoulder

[3]
[4]

Small Traffic Island Design [5] [4]

Notes: Large Traffic Island Design [5]

[1] Widen shoulders when right-turn radii or roadway width cannot be provided for large trucks. Design
widened shoulder pavement the same depth as the right-turn lane.
[2] Use turn simulation software (such as AutoTURN®) for the intersection design vehicle
[3] For turning roadway widths, see Chapter 1240.
[4] For additional details on island placement, see Exhibit 1310-15c.
[5] Small traffic islands have an area of 100 ft2 or less; large traffic islands have an area greater than 100
ft2.
General:
• Provide an accessible route for pedestrians (see Chapter 1510).
• 60° to 90° angle at stop or yield control.
• For right-turn corner design, see Exhibit 1310-6.

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1310.03(7)(c) Compound Right-Turn Lane

To design large islands, the common method is to use a large-radius curve for the turning traffic.
While this does provide a larger island, it also encourages higher turning speeds. Where
pedestrians are a concern, higher turning speeds are undesirable. An alternative is a compound
curve with a large radius followed by a small radius (see Exhibit 1310-15b). This design forces
the turning traffic to slow down.

Exhibit 1310-15b Traffic Island Designs: Compound Curve

60° to 90° angle

[4]

Edge of shoulder [1][2]

[2][3]

Notes:
[1] Widen shoulders when right-turn radii and roadway width
280 ft radius min cannot be provided for large trucks. Design widened shoulder
pavement the same depth as the right-turn lane.
[2] Use the truck turn simulation software (such as AutoTURN®)
for the intersection design vehicle.
[3] For turning roadway widths, see Chapter 1240.
[4] For right-turn corner design, see Exhibit 1310-6.
General:
Provide an accessible route for pedestrians (see Chapter 1510).
For additional details on island placement, see Exhibit 1310-15c.
1310.03(7)(d) Curbing
Provide vertical curb 6 inches or higher for:
• Islands with luminaires, signals, or other traffic control devices.
• Pedestrian refuge islands.
Also consider curbing for:
• Divisional and channelizing islands.
• Landscaped islands.
• Stormwater conveyance.
In general, except to meet one of the uses listed above, it is desirable not to use curbs on
facilities with a posted speed of 45 mph or above.
Avoid using curbs if the same objective can be attained with pavement markings.

Refer to Chapter 1230 for additional information and design criteria on the use of curbs.

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Exhibit 1310-15c Traffic Island Designs

R =1.5 ft

e
lan
1 ft min

rn
t-tu
gh
Ri
R=2.5 ft

Shoulder width [1]

Small Raised Traffic Island [2]

R=1.5 ft

1 ft min

lane
1 ft offset min

n
t-tur
Shoulder

Righ
width [1]

R=2.5 ft
R=2.5 ft

2 ft offset min

Shoulder width [1]

Large Raised Traffic Island [2]

Notes:
[1] For shoulder width at curbs, see Chapter 1230. For additional information on shoulders at turn lanes,
see 1310.03(6).
[2] Small traffic islands have an area of 100 ft2 or less; large traffic islands have an area greater than 100
ft2.
General:
Provide an accessible route for pedestrians (see Chapter 1510).

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1310.03(8) U-Turns
For divided multilane highways without full access control that have access points where the
median prevents left turns, evaluate the demand for locations that allow U turns. Normally, U
turn opportunities are provided at intersections. However, where intersections are spaced far
apart, U-turn median openings may be provided between intersections to accommodate U-
turns. Use the desirable U-turn spacing (see Exhibit 1310-16) as a guide to determine when to
provide U-turn median openings between intersections. Where the U-turning volumes are low,
longer spacing may be used.

Locate U-turn median openings where intersection sight distance can be provided.

Exhibit 1310-16 U-Turn Spacing

Urban/Rural Desirable Minimum

Urban [1] 1,000 ft [2]

Suburban ½ mile ¼ mile [3]
Rural 1 mile ½ mile
Notes:
[1] For design speeds higher than 45 mph, use suburban
spacing.
[2] The minimum spacing is the acceleration lane length
from a stop (see Exhibit 1310-14) plus 300 ft.
[3] For design speeds 60 mph or higher, the minimum
spacing is the acceleration lane length from a stop
(see Exhibit 1310-14) plus 300 ft.

When designing U-turn median openings, use Exhibit 1310-18 as a guide. Where the median is
less than 40 feet wide, with a large design vehicle, provide a U-turn roadway (see Exhibit 1310-
17). Design A, with the U-turn roadway after the left-turn, is desirable. Use Design A when the
median can accommodate a left-turn lane. Use Design B only where left-turn channelization
cannot be built in the median.

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Exhibit 1310-17 U-Turn Roadway

On-connection*

Design A

Off-connection*

Design B

*Design on- and off-connections in accordance with Chapter 1360.

Document the need for U-turn locations, the spacing used, and the selected design vehicle. If
the design vehicle is smaller than the largest vehicle using the facility, provide an alternate
route.

U-turns at signal-controlled intersections do not need the acceleration lanes shown in Exhibit
1310-18. For new U-turn locations at signal-controlled intersections, evaluate conflicts between
right-turning vehicles from side streets and U-turning vehicles. Warning signs on the cross street
might be appropriate.

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Exhibit 1310-18 U-Turn Median Openings

300 ft Acceleration length [1]

[2]

W
300 ft Acceleration length [1]

F2
[3] T

R
W

[3] T
F1 L

Vehicle W R L F1 F2 T

P 52 14 14 12 12 —
SU-30 87 30 20 13 15 10:1
CITY-BUS 87 28 23 14 18 10:1
WB-40 84 25 27 15 20 6:1
WB-67 94 22 49 15 35 6:1
U-Turn Design Dimensions
Notes:
[1] The minimum length of the acceleration lane is shown in Exhibit 1310-14. Acceleration lane may be
eliminated at signal-controlled intersections.
[2] When U-turn uses the shoulder, provide shoulder width sufficient for the intersection design vehicle
to make the turn and shoulder pavement designed to the same depth as the through lanes for the
acceleration length and taper.
[3] Lane width as determined by Chapters 1106 and 1230.
General: All dimensions are in feet.

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1310.04 Intersection Sight Distance

Providing drivers the ability to see stop signs, traffic signals, and oncoming traffic in time to
react accordingly will reduce the probability of conflicts occurring at an intersection. Actually
avoiding conflicts is dependent on the judgment, abilities, and actions of all drivers using the
intersection.

The driver of a vehicle that is stopped and waiting to cross or enter a through roadway needs
obstruction-free sight triangles in order to see enough of the through roadway to complete all
legal maneuvers before an approaching vehicle on the through roadway can reach the
intersection. Use Exhibit 1310-19a to determine minimum intersection sight distance along the
through roadway.

The sight triangle is determined as shown in Exhibit 1310-19b. Within the sight triangle, lay back
the cut slopes and remove, lower, or move hedges, trees, signs, utility poles, signal poles, and
anything else large enough to be a sight obstruction. Eliminate parking to remove obstructions
to sight distance. In order to maintain the sight distance, the sight triangle must be within the
right of way or a state maintenance easement (see Chapter 510).

The setback distance for the sight triangle is 18 feet from the edge of traveled way. This is for a
vehicle stopped 10 feet from the edge of traveled way. The driver is almost always 8 feet or less
from the front of the vehicle; therefore, 8 feet are added to the setback. When the stop bar is
placed more than 10 feet from the edge of traveled way, providing the sight triangle to a point 8
feet back of the stop bar is desirable.

Provide a clear sight triangle for a P vehicle at all intersections. In addition, provide a clear sight
triangle for the SU-30 vehicle for rural highway conditions. If there is significant combination
truck traffic, use the WB-67 rather than the SU-30. In areas where SU-30 or WB vehicles are
minimal and right of way restrictions limit sight triangle clearing, only the P vehicle sight
distance needs to be provided.

At existing intersections, when sight obstructions within the sight triangle cannot be removed
due to limited right of way, the intersection sight distance may be modified. Drivers who do not
have the desired sight distance creep out until the sight distance is available; therefore, the
setback may be reduced to 10 feet. Document the right of way width and provide a brief
analysis of the intersection sight distance clarifying the reasons for reduction. Verify and
document that there is no identified crash trend at the intersection. Document the intersection
location and the available sight distance as a Design Analysis.

If the intersection sight distance cannot be provided using the reductions in the preceding
paragraph, where stopping sight distance is provided for the major roadway, the intersection
sight distance, at the 10-foot setback point, may be reduced to the stopping sight distance for
the major roadway, with a Design Analysis and HQ Design Office review and concurrence. (See
Chapter 1260 for required stopping sight distance.) Document the right of way width and
provide a brief analysis of the intersection sight distance clarifying the reasons for reduction.
Verify and document that there is no identified crash trend at the intersection. Document the
intersection location and the available sight distance as a Design Analysis.

In some instances, intersection sight distance is provided at the time of construction, but
subsequent vegetative growth has degraded the sight distance available. The growth may be
seasonal or occur over time. In these instances, intersection sight distance can be restored

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through the periodically scheduled maintenance of vegetation in the sight triangle within the
WSDOT right of way or state maintenance easement.

At intersections controlled by traffic signals, provide sight distance for right-turning vehicles. For
intersections controlled by the geometry of roundabouts, see Chapter 1320.

Designs for movements that cross divided highways are influenced by median widths. If the
median is wide enough to store the design vehicle, with a 3-foot clearance at both ends of the
vehicle, sight distances are determined in two steps. The first step is for crossing from a stopped
position to the median storage. The second step is for the movement, either across or left into
the through roadway.

Design sight distance for ramp terminals as at-grade intersections with only left- and right-
turning movements. An added element at ramp terminals is the grade separation structure.
Exhibit 1310-19b gives the sight distance guidance in the vicinity of a structure. In addition,
when the crossroad is an undercrossing, check the sight distance under the structure graphically
using a truck eye height of 6 feet and an object height of 1.5 feet.

Document a brief description of the intersection area, sight distance restrictions, and traffic
characteristics to support the design vehicle and sight distances chosen.

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Exhibit 1310-19a Sight Distance at Intersections

Sight Line

V
V

Sight distance Sight distance

Time Gap (tg)

Si = 1.47Vtg Design Vehicle
in Sec
Where: Passenger car (P) 7.5
Si = Intersection sight distance (ft)
V = Design speed of the through roadway (mph) Single-unit trucks and
9.5
tg = Time gap for the minor roadway traffic to buses (SU-30 & CITY-BUS)
enter or cross the through roadway (sec) Combination trucks (WB-40
11.5
& WB-67)
Intersection Sight Distance Equation
Table 1 Note:
Values are for a stopped vehicle to turn left onto a
Notes: two-lane two-way roadway with no median and
grades 3% or less.
Adjust the tg values listed in Table 2 as follows:
Crossing or right-turn maneuvers: Intersection Sight Distance Time Gaps (tg)
Table 2
All vehicles subtract 1.0 sec
Multilane roadways:
Left turns, for each lane in excess of one to be crossed, and for medians wider than 4 ft:
Passenger cars add 0.5 sec
All trucks and buses add 0.7 sec
Crossing maneuvers, for each lane in excess of two to be crossed, and for medians wider than 4 ft:
Passenger cars add 0.5 sec
All trucks and buses add 0.7 sec
Where medians are wide enough to store the design vehicle, determine the sight distance as two
maneuvers.
Crossroad grade greater than 3%:
All movements upgrade for each percent that exceeds 3%:
All vehicles add 0.2 sec

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Exhibit 1310-19b Sight Distance at Intersections

(A) Si
X

n
X

8 ft See Detail A 18 ft
Sight obstruction
Detail A
Line of sight

(B)
8 ft
See Detail B
n b
X
b

Line of sight
18 ft Sight obstruction
X Detail B
Si

(C)
L Line of sight
Si
A
Curb, sidewalk, or
See Detail C other low sight HC
H1 obstruction Detail C
H2 Line of sight

For sight obstruction driver cannot see over: For crest vertical curve over a low sight

Si 
26  b  X  obstruction when S<L:

18  b  n 
Si 

100 L 2H 1  HC   2H 2  HC   2

A
Where:
Si = Available intersection sight distance (ft)
n = Offset from sight obstruction to edge of AS i2
L
lane (ft)
b = Distance from near edge of traveled way

100 2H 1  HC   2H 2  HC  2

to near edge of lane approaching from Where:

right (ft) (b=0 for sight distance to the left) Si = Available sight distance (ft)
X = Distance from centerline of lane to sight H1 = Eye height (3.5 ft for passenger cars;
obstruction (ft) 6 ft for all trucks)
[1]
H2 = Approaching vehicle height (3.5 ft)
HC = Sight obstruction height (ft)
L = Vertical curve length (ft)
A = Algebraic difference in grades (%)

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1310.05 Signing and Delineation

Use the MUTCD and the Standard Plans for signing and delineation criteria. Provide a route
confirmation sign on all state routes shortly after major intersections. (See Chapter 1020 for
additional information on signing.)

Painted or plastic pavement markings are normally used to delineate travel paths. For pavement
marking details, see the MUTCD, Chapter 1030, and the Standard Plans.

Contact the region or HQ Traffic Office for additional information when designing signing and
pavement markings.

1310.06 Procedures
Document design decisions and conclusions in accordance with Chapter 300. For highways with
limited access control, see Chapter 530.

1310.06(1) Approval
An intersection is approved in accordance with Chapter 300. Complete the following items, as
needed, before intersection approval:
• Intersection Control Type Approval (see Chapter 1300)
• Design Analyses approved in accordance with Chapter 300
• Approved Traffic Signal Permit (DOT Form 242-014 EF) (see Chapter 1330)

1310.06(2) Intersection Plans

Provide intersection plans for any increases in capacity (turn lanes) at an intersection,
modification of channelization, or change of intersection geometrics. Support the need for
intersection or channelization modifications with history; school bus and mail route studies;
hazardous materials route studies; pedestrian use; public meeting comments; etc.

For information to be included on the intersection plan for approval, see the Intersection/
Channelization Plan for Approval Checklist on the following website:

 www.wsdot.wa.gov/design/projectdev/

1310.06(3) Local Agency or Developer-Initiated Intersections

Intersections in local agency and developer projects on state routes must receive the applicable
approvals in section 1310.07(1) as part of the intersection design process.

The project initiator submits an intersection plan and the documentation of design decisions
that led to the plan to the region for approval. For those plans requiring a Design Analysis, the
Design Analysis must be approved in accordance with Chapter 300 prior to approval of the plan.
After the plan approval, the region prepares a construction agreement with the project initiator
(see the Utilities Manual).

1310.07 Documentation
Refer to Chapter 300 for design documentation requirements.

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1310.08 References
1310.08(1) Federal/State Laws and Codes
Americans with Disabilities Act of 1990 (ADA) (28 CFR Part 36, Appendix A)

Revised Code of Washington (RCW) 35.68.075, Curb ramps for persons with disabilities –
Required – Standards and requirements

Washington Administrative Code (WAC) 468-18-040, Design standards for rearranged county
roads, frontage roads, access roads, intersections, ramps and crossings

WAC 468-52, Highway access management – Access control classification system and standards

1310.08(2) Design Guidance

Local Agency Guidelines (LAG), M 36-63, WSDOT

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

1310.08(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO

Aspects of Traffic Control Devices, Highway Research Record No. 211, pp 1 18, “Volume
Warrants for Left-Turn Storage Lanes at Unsignalized Grade Intersections,” Harmelink, M.D.

Guidelines and Recommendations to Accommodate Older Drivers and Pedestrians, FHWA-RD-01-

051, USDOT, FHWA, May 2001

Highway Capacity Manual (HCM), Special Report 209, Transportation Research Board, National
Research Council

Intersection Channelization Design Guide, NCHRP 279

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1320.01 General
1320.02 Roundabout Types
1320.03 Capacity Analysis
1320.04 Geometric Design
1320.05 Pedestrians
1320.06 Bicycles
1320.07 Signing
1320.08 Pavement Marking
1320.09 Illumination
1320.10 Road Approach, Parking, and Transit Facilities
1320.11 Geometric Design Peer Review
1320.12 Documentation and Approvals
1320.13 References

1320.01 General
Modern roundabouts are near-circular intersections at grade. They are an effective intersection
type with fewer conflict points and lower speeds, and they provide for easier decision making
than other intersection types. They also require less maintenance than traffic signals. Well-
designed roundabouts have been found to reduce crashes (especially fatal and severe injury
collisions), traffic delays, fuel consumption, and air pollution. They also have a traffic-calming
effect by reducing vehicle speeds using geometric design rather than relying solely on traffic
control devices.

Roundabout design is an
iterative process.

A well-designed
roundabout achieves a
balance of safety and
efficiency.

Good design is a process

of creating the smooth
curvature, channelization,
and deflection required to
achieve consistent speeds,
well-marked lane paths,
and appropriate sight
distance.
Roundabout

The decision to install a roundabout is the result of an Intersection Control Evaluation (ICE) (see
Chapter 1300) approved by the region Traffic Engineer or other designated authority.

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1320.02 Roundabout Types

There are five basic roundabout types: mini, compact, single-lane, multilane, and teardrop
described in the following sections.

1320.02(1) Mini-Roundabouts

Mini-roundabouts are small single-lane roundabouts generally used in 25 mph or less

urban/suburban environments. Because of this, mini-roundabouts are typically not suitable for
use on higher-volume (greater than 6,000 AADT) state routes. In retrofit applications, mini-
roundabouts are relatively inexpensive because they normally require minimal additional
pavement at the intersecting roads. A 2-inch mountable curb for the splitter islands and the
central island is desirable because larger vehicles might be required to cross over it.

A common application is to replace a stop-controlled or uncontrolled intersection with a mini-

roundabout to reduce delay and increase capacity. With mini roundabouts, the existing curb and
sidewalk at the intersection can sometimes be left in place.

1320.02(2) Compact Roundabouts

Compact roundabouts are a hybrid of attributes found in mini- and single-lane roundabouts.
Similar to a mini-roundabout, a compact roundabout may require minimal additional pavement,
has a completely mountable center island, and in many cases existing curb or sidewalk can be
left in place. As a result, compact roundabouts rarely require the purchase of right of way.
Compact roundabouts are similar to single-lane roundabouts regarding design vehicle
assumptions, ability to process traffic volumes, and signing.

Compact roundabouts

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1320.02(3) Single-Lane Roundabouts

Single-lane roundabouts have single-lane entries at all legs and one circulating lane. They
typically have mountable raised splitter islands, a mountable truck apron, and a landscaped
central island.

Single-lane roundabout

1320.02(4) Multilane Roundabouts

Multilane roundabouts have at least one entry or exit with two or more lanes and more than
one circulating lane. The operational practice for trucks negotiating roundabouts is to straddle
adjacent lanes.

Multilane roundabout

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1320.02(5) Teardrop Roundabout

Teardrops are usually associated with ramp terminals at interchanges: typically, at diamond
interchanges. Teardrop roundabouts allow the “wide node, narrow link” concept. Unlike circular
roundabouts, teardrops do not allow for continuous 360° travel resulting in less vehicle conflicts
as traffic traveling on the crossroad (link) between ramp terminal intersections (nodes) does not
encounter a yield as it enters the teardrop intersections. At higher ADT locations this lack of
conflicting vehicles can result in a higher throughput, but can also result in limited gaps for the
off ramp approach. Consult HQ or region Traffic Office for guidance.

Teardrop roundabouts

1320.03 Capacity Analysis

Use the capacity analysis completed as part of the Intersection Control Evaluation (see Chapter
1300) to verify the number of lanes required for every individual movement in the design year.

1320.04 Geometric Design

1320.04(1) Selecting Shape and Placement

Roundabout shape is an important

decision, because the shape can
affect design elements that affect
safety performance and operation
of the roundabout.
1320.04(1)(a) Circular

The circular shape is the most

desirable roundabout shape when
constraints allow. If a circular shape
is not feasible, contact the region
Traffic Office to investigate other
shapes described below. Sometimes
a circular shape can be used by
slightly offsetting the placement of
Circular shape
the roundabout.

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1320.04(1)(b) Non-Circular

A non-circular roundabout is a good choice when constraints such as right of way, existing
roadway alignments, buildings, and/or environmentally sensitive areas influence the shape.

Experiment with different roundabout sizes and radii, and use design vehicle turning software
(such as AutoTURN®) to refine the shape to find the best operation while retaining desired
speeds.

Non-circular roundabout
with example dimensions

1320.04(2) Roundabout Design Elements

This section provides guidance for roundabout design elements. The photo below labels many of them.

Roundabout design elements

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1320.04(2)(a) Curbing

All curbing within a roundabout should be rolled. The type of rolled curbing appropriate for a
roundabout is shown in the Standard Plan Roundabout Cement Concrete Curbs: F-10.18.

Exception: existing curb untouched as part of a mini or compact roundabout installation may
remain.

1320.04(2)(b) Truck Apron

A truck apron is the mountable portion of the central island used to accommodate the turning
path of a design vehicle larger than a passenger vehicle or BUS, and helps to minimize the
overall footprint of the roundabout. Generally, the truck tractor can traverse the roundabout in
the circulating lane while the trailer is allowed to off track onto the apron. The apron is raised
above the circulating path to provide guidance for drivers in the circulating lane.

A truck apron’s width is based on the needs of the design vehicle. If buses are a consistent
vehicle using the intersection try to minimize apron use for all movements, however this is not a
requirement. Use turn simulation software (such as AutoTURN®) to fine tune the width of apron
needed, so as not to design an apron that won’t be used.

The apron color should be easily distinguishable in contrast with the adjacent circulating
roadway and pedestrian facilities. Work with the region Landscape Architect (HQ Roadside and
Site Development Section for regions without a Landscape Architect) for concrete color and
texture.

Roundabout showing colored

truck apron at central island
and at buffer area between
travel lanes and sidewalk

1320.04(2)(c) Central Island

The central island is the portion of the roundabout that is inside of the circulating roadway and
typically includes an inside truck apron and a landscaped area (except for mini-roundabouts and
compact roundabouts, which have no landscaped area and are entirely mountable).

Central island shape is a function of the site-specific needs of a roundabout intersection. It

doesn’t have to be an identical shape of the inscribed circle diameter (ICD) dimensions, but

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should support the design principles of deflection and low speeds, and the accommodation of
the design vehicle.

Roundabouts present opportunities to create community focal points, landscaping, and other
gateway features within an intersection. The central island may include enhancements (such as
landscaping, sculptures, or fountains), which serve both an aesthetic purpose and provide visual
indication of the intersection for approaching motorists (this is particularly important for high
speed approaches). Ideal central island treatments fit the context and result in minimal
consequence to any vehicle that may encroach on the non-mountable portion of the central
island. These treatments should not attract pedestrians to the central island, as pedestrians
should never cross the circulating roadway. Work with the region Landscape Architect (HQ
Roadside and Site Development Section for regions without a Landscape Architect) for central
island features. See Chapter 950 Public Art for policy and guidance.

1320.04(2)(d) Splitter Island

A splitter island is the raised island at each two-way leg between entering and exiting vehicles,
designed primarily to control the entry and exit speeds by providing deflection. They also
discourage wrong-way movements, and provide pedestrian refuge. Splitter islands can have
different shapes based on entry angle requirements and exit design speeds.

Raised channelization, or the appearance of raised curbing, is important, as research shows that
drivers will slow down when they perceive that the driving width is narrowing.

The length of the splitter island will vary (typical lengths: 30 ft. to 350 ft.) based on the terrain,
access considerations, site-specific
mainline and crossroad operational
speeds and the stepdown speeds to
the final desired entry speed, which
is usually 15–25 mph. (See
1320.04(3)(a) for using chicanes on
higher-speed roadways.)

Try to maximize the splitter island

width adjacent to the circulating
roadway. The larger achieved
width, the better a driver
approaching the roundabout can
perceive whether a driver in the
circulating lane will exit or continue
inside the roundabout. This results
in better gap acceptance. This may
also support a better pedestrian Splitter Island
refuge design.

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1320.04(2)(e) Inscribed Circle Diameter (ICD)

The Inscribed Circle Diameter (ICD), that is, the overall outside diameter of a roundabout, is
determined by the variables design vehicle, design speed, and the number of circulatory lanes.

The ranges of ICD in Exhibit 1320-1 are only suggestions to start a roundabout design. The ICD
for noncircular shapes should be defined with dimensions along the X and Y axis.

Exhibit 1320-1 Suggested Initial Design Ranges

Design Element Mini [1] Compact Single-Lane Multilane

Number of Lanes 1 1+ 1 2+

Inscribed Circle Diameter [2] 45’ – 80’ 65’ – 120’ 80’ – 150’ 120’ – 165’

Circulating Roadway Width N/A N/A 14’ – 19’ 29’

Entry Widths N/A N/A 16’ – 18’ 25’

Notes:
The “+” symbol used here means that a portion of the circulating roadway may have more
than one lane.
[1] Reserved for urban/suburban intersections with a 25 mph or less posted speed.
[2] The given diameters assume a circular roundabout; adjust accordingly for other shapes.
Some conditions may require ICDs outside ranges shown here.

1320.04(2)(f) Entry
1. Deflection

Ideal alignment offers an entry design that provides deflection, speed control, and reasonable
view angles to drivers while balancing property impacts and costs. While most intersections are
at 90º angles and most through movements are straight, deflection contributes to the safety
performance of a roundabout. Deflection is primarily achieved with the central island and
supporting it with splitter islands on all entries to the roundabout.

2. Alignment Offset

There are three alignment choices for attaching entry legs to the circulatory roadway:
 The offset left alignment is preferred. It constrains the entry, slowing a vehicle’s
approach speed, and opens up the exit for efficient egress.
 The symmetrical alignment (if needed) is acceptable for lower speed contexts such as
30 mph.
 The offset right alignment tends to allow faster entry speeds and constrains the exit; it
is undesirable.

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Offset left alignment (preferred)

3. Entry Angle

To achieve the proper amount of deflection for each approach to a roundabout, there is a range
of angle values that are desirable. This range is usually between 20 and 40 degrees. The purpose
of entry angle is so vehicles don’t hit broadside.

4. Entry Width

Entry width is determined by the turning template of the design vehicle turning through the
entry curve at the desired entry speed. The ranges of entry widths in Exhibit 1320-1 are only
suggestions to start a roundabout design.

Entry angle and width

5. Path Overlap

In a multilane roundabout, if the vehicles in the entry are aligned toward the central island or
the truck apron, the vehicle on the right is pointed toward the inside lane and tends to go in that
direction, while the vehicle on the left tends to be squeezed to the right toward the vehicle on
the right. Avoid path overlap. Avoid a design that aligns an entering vehicle at the incorrect lane
in the circulatory roadway. As a vehicle enters the circulating roadway it should be headed
directly toward its respective lane within the circulating roadway. For multilane roundabouts, if

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inside lane is pointing at truck apron this is also considered to be path overlap. If right entry lane
is pointing to left circulatory lane, then there is path overlap.

Path overlap conflict

Good path alignment

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1320.04(2)(g) Right-Turn Slip Lanes

Right-turn slip lanes are a proven way to increase the “life” of an intersection by removing traffic
that would otherwise enter the roundabout and reduce the available capacity to other
movements. If a right-turn movement has 250 vehicles/hour or more, or if over 40% of the total
approach volume is taking right turns, a slip lane should be considered.

The conflicting volume of vehicles on the merge will influence the length of merge lane prior to
termination. Speeds can be very low and vehicles can take turns at these low speeds.
Multimodal considerations will influence the length based on crosswalk location and bicycle use.

Right-turn slip lanes

showing merge and
yield termination

1320.04(3) Speed Control

Roundabout operation performance is dependent on low, consistent vehicle speeds. Low and
consistent operating speeds facilitate appropriate gap acceptance by an entering driver. Design
for travel path operating speeds between 15 mph and 25 mph (see 1320.04(3)(b)). Design to
have low-speed differentials (12 mph or under) between entering and circulating traffic.
Multilane roundabouts might have higher speeds along their respective travel paths, but
generally 30 mph or less.

The ideal design speed mechanism has the entry and circulating speeds being similar. This varies
due to size, shape and context of the roundabout.

The vehicle then moves into and through the circulation lane, being controlled all along by the
design speed of the circulating lane. The circulating design speed controls the exit speed;
therefore, the exit design speed, as calculated in the Travel Path section below, is not as critical.

Designing geometric entry speed control encourages lower speeds and lower speed differentials
at conflict points, which reduces the potential for collisions.

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1320.04(3)(a) Chicanes

Chicanes are a type of horizontal deflection used in traffic calming to reduce the speed of
vehicles. Research has shown that chicanes have value in slowing down higher approach speeds.

Chicane

Consider chicanes where posted speeds near the roundabout are 45 mph or higher. Design
chicane curves with successively smaller radii in order to successively reduce vehicle speeds
approaching the roundabout entry. Use Exhibit 1320-2 to determine the radii-speed relationship
(the radii are measured using the offsets recommended in the Travel Paths section). The normal
cross slope (superelevation in 1320-2) is 2% however, site conditions may require more based
on how you tilt the plane of the roundabout for site specific conditions. A minus (-) 2% drains
toward the central island.

Also, consider the grade of the roadways that enter the roundabout, because a vehicle can more
easily slow down on an upgrade than on a downgrade. Adjust the length of the deceleration
based on the “Adjustment Factors for Grades Greater Than 3%” in Design Manual Exhibit 1360-
10.

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1320.04(3)(b) Travel Paths

Travel path calculations can be used on all roundabout designs to get an understanding of
speeds for different paths throughout the roundabout. A travel path is the shortest path
through the roundabout, no closer than 5 feet from any curb face or lane line as shown. Use
Exhibit 1320-2 and R1 through R5 to determine Travel Path speeds.

Travel paths

Source: NCHRP

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Exhibit 1320-2 Radii-Speed Relationship on Approach Legs and R Value Relationships

1320.04(4) Grades
Do not use grades as a constraint during scoping to rule out a roundabout. Be aware of how the
profiles mesh with sight distances and ADA pedestrian requirements.
1320.04(4)(a) Circulatory Roadway
The circulatory roadway grade value should not exceed 4%. Terrain may require benching the
roundabout to fit conditions.
1320.04(4)(b) Grade Transitions for Roadway Entry and Exit to the Circulatory
Roadway
Consider the grade transitions and make them as long as feasible. When designing for
pedestrians see Chapter 1510 and work with region ADA subject matter expert to ensure that
grades for ADA compliance at all pedestrian crossing are met.

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1320.04(5) Circulatory Roadway Profile and Cross Slope

The preferred profile grades of the circulatory roadway of a roundabout are ±4% or flatter
radially around the circulatory lane(s). Profile grades steeper than ±4% require justification. It is
preferred to bench the roundabout if practicable to reduce profile grade.

Preferred grades
and cross slopes
cross slope

The preferred circulatory roadway cross slope may range from 1.5% to 4.0% (2.0% preferred),
away from the central island to promote lower circulating speeds, improve central island
visibility, minimize breaks in cross slope of entry and exit lanes, and facilitate drainage of water
to the outside of the roundabout.

Drawing shows preferred cross slopes. Site conditions and drainage may require slopes outside these
ranges.

1320.04(6) Design Tools

During the scoping or preliminary geometric design process, do not to use truck turning paths
alone as a constraint to eliminate a roundabout at an intersection. There are several design
tools available to aid in the design of a roundabout. It is important to understand how the
software works, its default settings, and its application to the design process.

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1320.04(6)(a) Design Vehicle Assumptions

While all highway-to-highway movements require accommodating a WB-67, there are certain
assumptions that must be made with software programs that replicate truck swept paths.
Determine which truck percentage defaults are to be used (recognizing that truck percentages
can range from 2% to 20%) so that different segments can be modeled accurately. Recognize
that within a set percentage, WB-67s may only represent a small sample of the entire truck
volume on any given day. Therefore, consider whether a WB-67 should be designed for, or
accommodated (also see Chapter 1103).
1. Designing for a WB 67

A roundabout that is being designed for a WB-67 may result in wider lane widths and a larger
Inscribed Circle Diameter. For this situation, rolled curb design is critical to the truck’s traversing
the roundabout (see Standard Plan F-10.18 for curb details). Outside aprons may not be needed
in many situations based on AutoTurn® modeling and knowledge of driver turning behavior
when encountering geometric features.
2. Accommodating a WB 67

A roundabout that is designed to accommodate a WB-67 assumes that a WB-67 could utilize
truck aprons to maneuver through the roundabout, if necessary, which should reduce the
overall footprint of the roundabout. For this situation, rolled curb is critical to the truck’s
traversing the roundabout confidently. Although outside truck aprons are needed infrequently,
there may be situations where the design may need to incorporate them. Contact HQ Traffic for
guidance.

1320.04(6)(b) Truck Swept Path

In some cases, roundabouts of the perfect circular variety with symmetrical roadway
attachments require less specific knowledge of truck-turning software and its applications.
However, when looking at a non-circular shaped roundabout where the combination of the
truck’s speed, its turning angle settings, its rear axle locations, and its alignment are the critical
design elements to address, a mastery of the software is required. Designers that are unfamiliar
with how to apply the software inputs accurately to model a truck’s swept path need to contact
HQ Traffic Office for guidance. Poor alignment of a truck swept path can result in unnecessarily
large roundabout footprints, higher than desired Travel Path speeds, or uncomfortable driving
maneuvers by the freight community.

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Assume that a truck will travel much slower through a roundabout than the Travel Path speed
calculated for passenger vehicles (see 1320.04(3)(b)). Adjust the software input to allow a
slower truck speed in order to make a good engineering judgment about how fast a truck may
use a roundabout (for example, for AutoTURN® use 5 mph). Design tool default settings don’t
necessarily allow the maximization of the tool and can prohibit the designer from getting a
good, balanced design between passenger car speeds and truck accommodation.

Single lane roundabout - Truck using the truck apron

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When using a truck-turning software tool like AutoTURN® on multilane roundabouts, assume a
truck’s travel path will occupy (straddle) parts of two adjacent lanes.

Multilane roundabout - truck straddles lanes

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1320.04(7) Sight Distance

Sight distance is an important design consideration at roundabouts. Restricting sight distance

across the central island with strategic landscaping may enhance the intersection by making the
intersection a focal point and encouraging lower speeds. Work with the region Traffic Engineer
and Landscape Architect (HQ if there is no region contact) to determine this balance. Provide
sight triangle plan sheets for consideration of landscape design.

1320.04(7)(a) Stopping

Use the design stopping sight distance in Chapter 1260. Anticipated speeds throughout the
roundabout can be calculated using Exhibit 1320-2, based on the Travel Path radius and
direction of the particular curve. The design stopping sight distance is measured along the
vehicle’s path as it follows the curvature of the roadway; it is not measured as a straight line.

Sight distance – Approach and Exit

1320.04(7)(b) Intersection

Provide minimum intersection sight distance. Longer sight distances can lead to higher vehicle
speeds that reduce gap opportunities for entering vehicles. For intersection sight distance at
roundabouts, provide entering vehicles a clear view of traffic on the circulating roadway and on
the immediate upstream approach in order to aid in judging an acceptable gap.

The intersection sight distance at roundabouts is given in Exhibit 1320-3. The S1 intersection
sight distance is based on the average of the entering and circulating speeds, and the S2
intersection sight distance is based on the left-turning speed. The sight distance may also be
calculated using the intersection sight distance equation given in Chapter 1310 using a time gap
(tg) of 4.5 seconds.

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Exhibit 1320-3 Intersection Sight Distance

200
Intersection Sight Distance, S (ft)
180

160

140

120

100

80

60
10 15 20 25 30

Design Speed, V (mph)

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1320.04(8) Railroad Crossings

Although it is undesirable to locate any intersection near an at-grade railroad crossing, this
situation exists at many locations on the highway system. Experience shows that a roundabout
placed near a crossing has some operational advantages. If there is a railroad crossing near the
roundabout contact HQ Traffic Office for further guidance.

1320.05 Pedestrians
As part of the approved ICE it has already been determined whether pedestrians will use the
roundabout and, if so, which legs (see Chapter 1300).

With the knowledge of where pedestrian facilities are needed, design the roundabout while
keeping in mind the ADA requirements for crosswalks, sidewalks, paths, and other pedestrian
facilities.

1320.05(1) Crossing Location

The pedestrian crossing located on the entry side of a roundabout leg should be at least 20 feet
from the yield line so that a pedestrian can walk behind a vehicle that is waiting at the yield line.
If there is an extremely large truck percentage, consider moving the crossing to accommodate
the most common truck.

The crossing located in the exit side of the roundabout leg can be closer to the roundabout,
because as the vehicles leave the roundabout, they accelerate and make it harder to find a
break in traffic. As speed increases, drivers are less likely and less able to stop. Verify that no
significant, large sight obstructions are located within the sight lines.

1320.05(2) Splitter Island Pass Through

Design the splitter island pass through a minimum of 5 feet

wide, or the width of the sidewalk, whichever is greater.
The length of the pass through (measured back of curb to
back of curb of the splitter island) is to be a minimum of 6
feet long measured along the shortest section of the
pedestrian path. Consider a “V” shape pass through as
shown.

1320.05(3) Buffers

Wherever feasible, separate sidewalks from the curb with a

buffer. Landscaping or colored concrete are acceptable for
the buffer. See WSDOT Standard Plan F10-18 for dimension
details. Do not compromise required vehicle sight triangle
needs.

The buffer discourages pedestrians from crossing to the

central island or cutting across the circulatory roadway of Splitter island pass through
the roundabout. It also helps guide pedestrians with vision
impairments to the designated crosswalks, and can
accommodate the occasional inexperienced truck driver who encroaches up onto a curb while
traversing through the roundabout.

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1320.05(4) Curb Ramps

Roundabouts with buffers typically have combination-type curb ramps; otherwise, parallel curb
ramps are normally used. (See Chapter 1510 and the Standard Plans for curb ramp information.)

1320.05(5) Sight Triangles

A vehicle sight triangle specific to pedestrians (see 1320.04(7)) must include the whole curb
ramp, including the landing, where pedestrians are likely to wait to cross.

It is also important that pedestrians are also able to see approaching vehicles.

1320.05(6) Pedestrian Beacons

On multilane roundabouts, consider installing pedestrian beacons to warn drivers when a

pedestrian wants to cross the roadway. Work with the region Traffic Engineer on types and
locations of pedestrian beacons.

Pedestrian beacons

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1320.06 Bicycles
Provide bicyclists with similar options to negotiate roundabouts as they have at other
intersections. Consider how they navigate either as motor vehicles or pedestrians depending on
the size of the intersection, traffic volumes, their experience level, and other factors.

Bicyclists are often comfortable riding through single-lane roundabouts in low-volume

environments in the travel lane with motor vehicles, as speeds are comparable and potential
conflicts are low.

At larger or busier roundabouts, cyclists may be more comfortable using ramps connecting to a
sidewalk around the perimeter of the roundabout as a pedestrian. Where bicycle lanes or
shoulders are used on approach roadways, they should end before the geometry changes the
approach to the roundabout.

Contact the HQ Design Office for bicycle ramp design options.

Bicycle rider using lane

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1320.07 Signing
The graphic shown is an example of
potential signing for a single-lane
roundabout. For additional information,
refer to the MUTCD, Plan Sheet Library,
and the Standard Plans for details on
signing.

A preliminary sign plan is developed to

identify existing and proposed signing on
state highways. Sign plans on state routes
are to be reviewed and approved by the
region Traffic Engineer and then
furnished to the HQ Traffic Office for
review.

The plan provides an easily understood

graphic representation of the signing, and
it provides statewide uniformity and
consistency for regulatory, warning, and
guide signs at roundabouts on the state
highway system. For roundabouts located
near a port, industrial area, or route that
accommodates oversize loads, consider
using perforated square steel posts. Signing example

1320.08 Pavement Marking

See Standard Plan M-12.10 for roundabout pavement marking details. Consult region Traffic on
traffic pavement markings and materials.

1320.09 Illumination
Provide illumination for each of the conflict points between circulating and entering traffic in the
roundabout and at the beginning of the raised splitter islands. Illuminate raised channelization
or curbing. Position the luminaires on the upstream side of each crosswalk to improve the
visibility of pedestrians. Light the roundabout from the outside in toward the center. This
improves the visibility of the central island and circulating vehicles to motorists approaching the
roundabout. Ground-level lighting within the central island that shines upward toward objects in
the central island can also improve their visibility. Consult with the region Traffic office for
illumination design. (See Chapter 1040 for additional information on illumination.) On higher-
speed approaches, consider internally illuminated bollards (IIB) in lieu of other illumination.

1320.10 Road Approach, Parking, and Transit Facilities

Road approach (road or driveway) connections to the circulating roadway are not allowed at
roundabouts unless they are designed as a leg to the roundabout. It is desirable that road
approaches not be located on the approach or departure legs within the length of the splitter
island. The minimum distance from the circulating roadway to a road approach is controlled by
corner clearance using the outside edge of the circulating roadway as the crossroad. When

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minimum corner clearance cannot be met, document the decision in accordance with Chapters
530 and 540.

If a parcel adjoins two legs of the roundabout, it is acceptable to provide a right-in/right-out

driveway within the length of the splitter islands on both legs. This provides for all movements;
design both driveways to accommodate their design vehicles.

Roadways between roundabouts may have restrictive medians with left-turn access provided
with U-turns at the roundabouts.

Parking is not allowed in the circulating roadway or on the entry or exit roadway within the
length of the splitter island.

Transit stops are not allowed in the circulating roadway, in the approach lanes, or in the exit
lanes prior to the crosswalk. Locate transit stops on the roadway before or after the
roundabout, in a pullout, or where the pavement is wide enough that a stopped bus does not
block the through movement of traffic or impede sight distance.

Right in / right out driveways

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1320.11 Geometric Design Peer Review

Conduct a peer review of the roundabout design with the following participants.
 Region Traffic Office
 Assistant State Traffic Engineer
 Region Project Development Engineer or Engineering Manager
 Assistant State Design Engineer

The intent of this peer review is to review, discuss, evaluate, and provide feedback on the 2-D
roundabout layout design in order to finalize the channelization plan.

1320.12 Documentation and Approvals

Refer to Chapter 300 for design documentation and approval requirements.

1320.13 References

1320.13(1) Federal/State Laws and Codes

See Chapter 1510 for Americans with Disabilities Act Policy and references

Revised Code of Washington (RCW) 47.05.021, Functional classification of highways

Washington Administrative Code (WAC) 468-58-080, Guides for control of access on crossroads
and interchange ramps

1320.13(2) Design Guidance

Roundabout Cement Concrete Curbs: Standard Plan F-10.18-01

Roundabout Pavement Markings: Standard Plan M-12.10

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA, as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21 01, WSDOT

Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications),
M 41-10, WSDOT

1320.13(3) Supporting Information

Roundabouts: An Informational Guide (First edition 2000), FHWA-RD-00-067, USDOT, FHWA

 http://www.fhwa.dot.gov/publications/research/safety/00067/index.cfm

Roundabouts: An Informational Guide (Second Edition 2010), NCHRP Report 672, Transportation
Research Board, 2010  http://nacto.org/docs/usdg/nchrprpt672.pdf

Highway Capacity Manual 2010 (HCM 2010), Transportation Research Board, National Research
Council, Washington D.C., 2000

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A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO

“Crash Reductions Following Installation of Roundabouts in the United States,” Insurance

Institute for Highway Safety, March 2000
 https://www.dot.ny.gov/main/roundabouts/files/insurance_report.pdf

Understanding Flexibility in Transportation Design – Washington, WSDOT, 2005

 www.wsdot.wa.gov/research/reports/600/638.1.htm

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Chapter 1330 Traffic Control Signals
1330.01 General
1330.02 Procedures
1330.03 Intersection Design Considerations
1330.04 Conventional Traffic Signal Design
1330.05 Preliminary Signal Plan
1330.06 Operational Considerations for Design
1330.07 Documentation
1330.08 References

1330.01 General
Traffic control signals are automated traffic control devices that warn or direct motorists to take
a specific action. Traffic control signals are used to control the assignment of right of way at
locations where conflicts with motorists, bicyclists, and pedestrians exist or where passive
devices such as signs and markings do not provide the necessary flexibility of control to move
motorists, bicyclists, and pedestrians in an efficient manner.

The decision to install a traffic signal is the result of an Intersection Control Evaluation (ICE) (see
Chapter 1300) that is approved by the region Traffic Engineer or other designated authority.

1330.02 Procedures

1330.02(1) Traffic Signal Permit

State statutes (RCWs) require WSDOT approval for the design and location of all conventional
traffic signals and some types of beacons located on city streets forming parts of state highways.
Approval by WSDOT for the design, location, installation, and operation of all other traffic
control signals installed on state highways is required by department policy.

The Traffic Signal Permit (DOT Form 242-014 EF) is the formal record of the signal warrant
analysis required by the MUTCD and the department’s approval of the installation and type of
signal. Permits are required for the following types of signal installations:
 Conventional traffic signals
 Emergency vehicle signals
 Intersection control beacons
 Lane control signals
 Movable bridge signals
 Ramp meter signals
 Pedestrian signals
 Pedestrian Hybrid Beacon signals (“HAWK” signals)
 Temporary traffic signals (only when not being used in place of a permanent, permitted
signal)
 Queue-cutter traffic signals

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The Permit and its supporting data must be included in the Design Documentation Package
(DDP.) The permit is completed by the requesting agency and submitted, complete with
supporting data, through the region Traffic Office to the approving authority for approval. See
1330.02(1)(a) for Signal Warrant information required as part of the supporting documentation.

The approving authority is the Regional Administrator or authorized delegate. The approving
authority approves or denies the application and sends it back to the region Traffic Office. The
region Traffic Office retains a record of the approved permit and supporting data and forwards a
copy of the Permit and the supporting data to the State Traffic Engineer at WSDOT
Headquarters (HQ). Preserve the approved permit as required by 1330.07 Documentation.

Emergency vehicle signals require annual permit renewal. The region Traffic Office reviews the
installation for compliance with requirements. If satisfactory, the permit is renewed by the
Regional Administrator with a letter to the operating agency. A copy of this letter is also sent to
the State Traffic Engineer.

Permits are not required for portable traffic signals, speed limit sign beacons, stop sign beacons,
or lane assignment signals at toll facilities.

A new permit application is required when the level of control is increased, such as changing
from an intersection control beacon to a conventional traffic signal or adding an approach to an
existing signal system.

For a reduction in the level of control, such as converting a conventional signal to a flashing
intersection beacon or removal of the signal, submit the “Report of Change” portion of the
traffic signal permit, complete with supporting data, to the approving authority, with a copy to
the region Traffic Office and State Traffic Engineer.

If experimental systems are proposed, region Traffic Engineer review and approval is required.
The region Traffic Office will send the approved proposal to the State Traffic Engineer for review
and approval. The State Traffic Engineer will forward the approved proposal to FHWA for their
approval. A copy of the approval from FHWA will be returned and must be preserved as
required by 1330.07 Documentation.

Any signal system requiring a permit, with the exception of Ramp Meter signals, also requires
Preliminary Signal Plan approval from the WSDOT HQ Traffic Office (see 1330.05).

1330.02(1)(a) Signal Warrants

A signal warrant is a minimum condition that is to be met before a signal may be considered for
installation. Satisfying a warrant does not mandate the installation of a traffic signal. The
warranting condition(s) supports the inclusion of a traffic signal for consideration as part of the
ICE performed during the scoping of the project (see Chapter 1300). For a list of the traffic signal
warrants and information on how to use them, see the Manual on Uniform Traffic Control
Devices (MUTCD). Contact the region Traffic Engineer for region specific practices.

Address all warrants listed in the currently adopted MUTCD as part of the Signal Warrant
Analysis. Mark warrants which do not apply as “Not Applicable” and include a basic supporting
statement or similar justification. Include the Signal Warrant Analysis in the Signal Permit
supporting data. For Warrant 7, the three year period must be used for all traffic signals
installed on state highways as described in FHWA Interim Approval IA-19
(https://mutcd.fhwa.dot.gov/resources/interim_approval/ia19/index.htm).

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1330.02(2) Responsibility for Funding, Construction, Maintenance, and

Operation
Responsibility for the funding, construction, maintenance, and operation of traffic signals on
state highways has been defined by legislative action and Transportation Commission
resolutions (see Exhibit 1330-1). Responsibilities vary depending on location, jurisdiction, and
whether or not limited access control has been established. Limited access as used in this
chapter refers to full, partial, or modified limited access control that has been established as
identified in the Access Control Tracking System:
 http://www.wsdot.wa.gov/design/accessandhearings/

Exhibit 1330-1 Responsibility for Facilities

Responsibility for Various Types of Facilities on State Highways

Reversible Lane
Traffic Signals, Pedestrian
Emergency Signals &
Area Responsibility Signals, & Intersection
Vehicle Signals Movable Bridge
Control Beacons
Signals
Finance ESD [1] City [2] City [2]
Cities with a
Construct ESD [1] City [2] City [2]
population of
Maintain ESD [1] City [2] City [2]
27,500 or greater
Operate ESD [1] City [2] City [2]
Finance ESD [1] State/County [3] /Other [4] State
Construct ESD [1] State/County [3] /Other [4] State
All other locations
Maintain ESD [1] State State
Operate ESD [1] State State
Notes:
[1] ESD refers to the applicable Emergency Service Department.
[2] Does not apply to state highways with established limited access control (see 1330.02(2)(c)).
[3] Beyond corporate limits due to county activity (see 1330.02(2)(d)).
[4] Other refers to signals proposed by or required due to third party activity (see 1330.02(2)(g)).

(a) Inside the corporate limits of cities with a population of 27,500 or greater where there is
no established limited access control: The city is responsible for the funding, construction,
maintenance, and operation of traffic signals. Population figures can be found at:
 www.ofm.wa.gov/pop/

(b) Inside the corporate limits of cities with a population of less than 27,500: WSDOT is
responsible for funding, construction, maintenance, and operation of traffic signals.
Population figures can be found at:  www.ofm.wa.gov/pop/

(c) Inside the corporate limits of cities with a population of 27,500 or greater where there is
established limited access control: WSDOT is responsible for funding, construction,
maintenance, and operation of traffic signals. Population figures can be found at:
 www.ofm.wa.gov/pop/

(d) Outside the corporate limits of cities and outside established limited access control areas:
WSDOT is responsible for funding, construction, maintenance, and operation of a traffic
signal when a new state highway crosses an existing county road. When a new county road
intersects an existing state highway, WSDOT is responsible for only the maintenance and
operation of a traffic signal. The county is responsible for the construction costs of the
traffic signal and associated illumination. When it is necessary to construct a traffic signal at

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an existing county road and state highway intersection, the construction cost distribution is
based on the volume of traffic entering the intersection from each jurisdiction’s roadway.
The county’s share of the cost, however, is limited to a maximum of 50%. The state is
responsible for maintenance and operation (WAC 468-18-040).

(e) Outside the corporate limits of cities and inside established limited access control areas:
WSDOT is responsible for funding, construction, maintenance, and operation of traffic
signals.

(f) Emergency vehicle signals: The emergency service agency is responsible for all costs
associated with emergency vehicle signals.

(g) Third party agreement signals: At those locations where WSDOT is responsible for traffic
signals and third party activity justifies the installation of a traffic signal, as determined by
an ICE, the following rules apply:
 The third party is responsible for funding the design and construction of the traffic
signal system, unless another arrangement is agreed upon with WSDOT.
 The third party obtains a traffic signal permit.
 The third party agrees to design and construct the traffic signal in conformance
with WSDOT’s guidelines and requirements.
 The third party agrees to submit the design and construction documents to
WSDOT for review and approval by the region Traffic Engineer.
 Preserve all third party provided documents and any third party agreement(s) as
required by 1330.07 Documentation.

1330.03 Intersection Design Considerations

Signalized intersections require different design considerations than non-signalized
intersections. These elements should be considered as early as the ICE process (see Chapters
1300 and 1310 for further guidance.) This Section discusses basic intersections with relatively
simple geometry. For more complex or innovative intersection layouts such as Diverging
Diamond Interchanges, Displaced Left Turns, or Single Point Urban Interchanges, contact the
WSDOT HQ Traffic Office for support.

Consider providing an unrestricted through lane on the major street of a T intersection

(sometimes referred to as a Continuous Green “T” (CGT) intersection). This design allows for one
traffic movement to flow without restriction. When this is used on through roadways with a
posted speed of 45 MPH or greater, the through lane must be separated by a physical barrier or
the through movement must also be signalized. If there is a crosswalk across the through lane,
the through lane must be signalized. Exhibit 1330-2 shows an example of a CGT intersection.

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Exhibit 1330-2 Example Continuous Green “T” (CGT) Intersection Layout

1330.03(1) Left Turns

It is recommended that a left turn storage lane be provided for all main line roadways where left
turns are allowed. This helps to avoid having stopped traffic in a through lane with a green
through signal display. This also helps to support potential future changes in left turn
operations. See Section 1330.06(1) for additional discussion.

Left-turning traffic can operate more efficiently when the opposing left-turn lanes are directly
opposite each other. When a left-turn lane is offset into the path of an opposing through lane,
the left-turning driver may assume the opposing vehicles are also in a left-turn lane and fail to
yield. To prevent this occurrence, less efficient split phasing may be necessary. (See Chapter
1310 for guidance on lane offsets and opposing left-turn clearance.) Where there are opposing
through lanes but no opposing left turn lane, install a striped or raised median area opposite the
left turn lane if possible.

Place stop lines so that they are out of the path of conflicting left turns. Check the geometric
layout by using turning templates or a computerized vehicle turning path program (such as
AutoTURN®) to determine whether the proposed layout and phasing can accommodate the
design vehicles. Also, check the turning paths of opposing left-turn movements. In many cases,
the phase analysis might recommend allowing opposing left turns to run concurrently, but the
intersection geometrics are such that this operation cannot occur. The intersection should be
large enough to accommodate opposing left turning vehicle paths with a 4-foot minimum (12-
foot desirable) separation between them. Where this separation cannot be achieved, less
efficient signal phasing may be required to accommodate opposing left turns.

Some intersections may have multi-lane left turns. At locations with closely spaced
intersections, a multi-lane left-turn storage area might be the only solution to reduce the
potential for the left-turn volume to back up into an adjacent intersection. As with single left
turn lanes, the intersection should be large enough to accommodate opposing left turning
vehicle paths with a 4-foot minimum (12-foot desirable) separation between them. Where this
separation cannot be achieved, less efficient signal phasing may be required to accommodate
opposing left turns.

At smaller intersections, the opposing single-lane left-turn movement might not be able to turn
during the two-lane left-turn phase and it might be necessary to reposition this lane. If the
opposing left turns cannot time together, the reduction in delay from the two-lane left-turn

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phase is likely to be nullified by the requirement for a separate opposing left-turn phase. Exhibit
1330-3 shows two examples of two-lane left turns with opposing single-left arrangements.

Two receiving lanes are required for two-lane left-turn movements. In addition, these receiving
lanes are to extend well beyond the intersection before reducing to one lane. A lane reduction
immediately beyond the intersection can cause delays and backups into the intersection
because the left-turning vehicles usually move in dense platoons, which may make merging and
lane changes difficult. (See Chapter 1310 for guidance on lane reductions on intersection exits.)

Exhibit 1330-3 Left-Turn Lane Configuration Examples

Turning paths for

two-lane left turn

Conflict point
Turning path for
opposing single
left turn

Left-turn storage lane

not offset to clear
opposing double lefts

Left-Turn Lane Configuration Preventing Concurrent Phasing

Single left turn lane not offset – overlapping left turn paths

4' minimum Turning paths for

12' preferred two-lane left turn

Turning path for opposing

single left turn
Left-turn storage lane
offset to clear opposing
double lefts

Left-Turn Lane Configuration With Concurrent Phasing

Offset single left turn lane – opposing lefts no longer in conflict

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1330.03(2) Right Turns

Large right-turn curb radii at intersections sometimes have impacts on traffic signal operation.
Larger radii allow faster turning speeds and might move the pedestrian entrance point farther
away from the intersection area. Pedestrian crossing times are increased because of the longer
crossing, thereby reducing the amount of time available for vehicular traffic. (See Chapter 1310
for guidance on determining these radii.)

At intersections with large right-turn radii, consider installing raised traffic islands. These islands
are primarily designed as pedestrian refuge areas. (See Chapter 1510 for pedestrian refuge
islands and traffic island designs.) Traffic islands may decrease the required pedestrian clearance
intervals; however, large radii and raised traffic islands may make it difficult for pedestrians to
navigate the intersection. Where pedestrians are expected to cross a right turn lane to a traffic
island, it is recommended to use a compound right turn-lane design as shown in Chapter 1310.

1330.03(3) Pedestrian Features

See Chapter 1510.

1330.03(4) Road Approaches and Driveways

If roadway approaches and driveways are located too close to an intersection, the traffic from
these facilities can affect signal operations. Consider eliminating the accesses or restricting them
to “right in/right out”. If a driveway or road approach is directly opposite a leg of the
intersection, that approach may be signalized. If the approach is signalized, it must be signalized
as if it were a standard intersection leg, and the pedestrian crossing across the approach must
also be signalized as if it were a standard crosswalk.

Management of driveways and road approaches should be determined early (preferably no later
than scoping) so that they can be considered and addressed in the design. (See Chapters 530
and 540 for further guidance.) Consider shifting the location of advance detection upstream to
clear an access point so that vehicles entering from the access point will not affect detection and
operation of the signal.

1330.03(5) Skewed Intersections

Skewed intersections, because of their geometry, are challenging to signalize and delineate.
Where feasible, modify the skew angle to provide more normal approaches and exits. In many
cases, the large paved areas for curb return radii at skewed intersections can be reduced when
the skew angle is reduced. (See Chapter 1310 for requirements and design options.) Visibility of
pedestrians is of particular concern, and must also be taken into consideration.

1330.03(6) Transit Stops

Transit stop and pullout locations should be located on the far side of the intersection to
minimize their impacts on signal operation. (See Chapter 1430 for transit stop and pullout
designs.)

1330.03(7) Railroad Crossings

Where railroad preemption is used at a signalized intersection, install left and right turn lanes
for the movements leading to the leg of the intersection with the railroad crossing if possible.

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This greatly improves the efficiency of the signal during railroad preemption when turns are
restricted. Also consider providing a left-turn lane for the minor leg opposing the railroad
crossing. This will allow for more effective signal operations during long periods of railroad
preemption.

Where there is less than 40 feet between the nearest rail and the normal location of the stop
line, do not install a stop line between the tracks and the intersection. Use the same stop line
for the traffic signal and the rail crossing instead. Exhibit 1330-4 shows recommended
intersection features for intersections near rail crossings.

Contact the WSDOT HQ Traffic Office for assistance with standalone queue-cutter signals.

Exhibit 1330-4 Recommended Features for Intersections near Rail Crossings

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1330.04 Conventional Traffic Signal Design

1330.04(1) General
The goal of any traffic signal design is to assign right of way in the most efficient manner
possible and still be consistent with traffic volumes, intersection geometrics, and safety.

An advanced signalized intersection warning sign and beacon assembly to warn motorists of a
signalized intersection should be installed when either of the two following conditions exists:

(a) The visibility requirements in the MUTCD are not achievable.

(b) The posted speed is 55 mph or higher and the next nearest signalized intersection is more
than 2 miles away; this does not apply to freeway off-ramps.

This warning sign and beacon assembly consists of a W3-3 sign with Type IV reflective sheeting
and one or two continuously flashing beacons. Where two beacons are used, the beacons
should flash alternately instead of simultaneously. Locate the sign in advance of the intersection
in accordance with Table 2C-4 (Condition A) of the MUTCD. The warning sign and beacon
assembly may be omitted with approval from the region Traffic Engineer.

1330.04(2) Signal Phasing

With some exceptions, the fewer the traffic signal phases, the more efficient the operation of
the traffic signal. The number of phases required for efficient operation is related to intersection
geometrics, traffic volumes, composition of traffic flow, turning movement demands, and
desired level of driver comfort. The traffic movements at an intersection have been
standardized to provide consistency in both traffic signal design and driver expectations. (See
Exhibit 1330-5 for standard intersection movements, signal head (display) numbering, and
standard phase operation.)

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Exhibit 1330-5 Standard Intersection Movements, Head Numbers, and Phase Operation

For WSDOT operated signals, the region Signal Operations Engineer will develop the signal
phasing plan or review proposed phasing for systems designed by others. For signals operated
by other jurisdictions, the operating jurisdiction should be involved in signal phasing
development. Phasing development is addressed in 1330.06 Operational Considerations for
Design. Phasing development should begin as soon as the decision is made to install a traffic
signal and may begin as early as the intersection control evaluation. Provide the proposed
channelization plans and traffic count data to the region Signal Operations Engineer or phasing
designer as early as possible, as phasing information is required to complete the signal system
design.

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For WSDOT owned and operated signals, vehicle and pedestrian movement phase numbering is
standardized to provide uniformity in signal phase numbering, signal display numbering,
preemption channel identification, detection numbering, and circuit identification. For signals
owned and operated by other jurisdictions, refer to that jurisdiction’s guidelines for phase and
equipment numbering. The following are general guidelines for the WSDOT numbering system:
1. Phases 2 and 6 are normally assigned to the major street through movements, with phase 2
assigned to the northbound or eastbound direction of the major street. This results in phase
2 being aligned with the direction of increasing mileposts.
2. Phases 1 and 5 are normally assigned to the major street protected left-turn movements.
3. Phases 4 and 8 are normally assigned to the minor street through movements, with phase 4
normally assigned to the approach to the left of the phase 2 approach (as viewed from the
phase 2 stop line).
4. Phases 3 and 7 are normally assigned to the minor street protected left-turn movements.
5. Phasing on new signals installed within an already signalized corridor should be assigned to
match the existing corridor phasing – even if it doesn’t follow the standard phasing
conventions listed above.
6. At T intersections, the movement on the stem of the T is normally assigned to either phase 4
or phase 8. Which phase is used will normally depend on the major street phase
assignments.
7. At intersections where split phasing is used (opposing directions time separately) assign
phases normally but show the split phase phasing diagram, unless otherwise directed by
maintenance and operations staff.
8. Signal displays are numbered as follows:

a. The first number indicates the signal phase and the second number is the number of
the signal head, counting from centerline (or left edge line) to the right edge line of
the approach. For example, signal displays for phase 2 are numbered, as viewed from
left to right, 21, 22, 23, and so on. If the display is an overlap, the designation is the
letter assigned to that overlap. For example, signal displays for overlap A are number
A1, A2, A3, and so on.

b. If the display is protected/permissive, the display is numbered with the phase number
of the through display followed by the phase number of the left-turn phase. For
example, a protected/permissive signal display for phase 1 (the left-turn movement)
and phase 6 (the compatible through movement) is numbered 61/11. For overlap
right turns, the protected portion may either be an overlap phase, or it may be the
same phase as the complementing left turn phase.

With a conventional protected/permissive left-turn display, the circular red, yellow,

and green displays are connected to the through phase (phase 6, in this example)
controller output and the steady yellow and green arrow displays are connected to
the left turn phase (phase 1, in this example) controller output.

When a flashing yellow arrow display is used, coordinate with the Signal Operations
Engineer and signal maintenance group to determine appropriate wiring. For new
cabinets, always specify an auxiliary output rack when protected/permissive phasing
will be used.

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9. Pedestrian displays and detectors are numbered with the first number indicating the signal
phase and the second number as either an 8 or 9. For example, pedestrian displays and
detectors 28 and 29 are assigned to phase 2. If there are more than two displays or
detectors for a single pedestrian phase, use letter suffixes for additional displays and
detectors (28A / 29A, 28B / 29B, etc.).
10. Vehicle detector numbering depends on the type of detection:

a. Induction loop detectors use three digit numbers for designation. The first number
represents the phase. The second number represents the lane number, starting from
the left lane and moving towards the right edge line. The third number represents the
loop number counting from the stop line back. For example, detection loops for phase
2 detectors are numbered 211, 212, 213 for lane 1; 221, 222, 223 for lane 2; and so
on. For loops tied together in series for a single detection channel, such as a three
loop series stop line detector, the individual loops in the series use a letter suffix. For a
stop line detector in lane 1 for phase 2, using three loops in series, the loops would be
designated 211A, 211B, and 211C.

b. Video detectors are designated V#, where “#” is the through phase number for that
approach, even if it will cover additional phases (such as left turn or overlap) for that
approach. If the video detector is for advance detection, the suffix “A” is added. For
example, the advance video detector for phase 6 would be V6A.

Video detection zones may be drawn on the contract plans if desired, but these will
normally be field established and adjusted and may not end up as shown in the plans.
If used, video detection zones are labeled the same as loop detectors, but with a “V”
suffix. For example, the stop line video detection zone for phase 5 would be 511V.

c. Radar detectors are designated similar to video detectors, but use an “R” prefix in
place of the “V”. For example, the advance radar detector for phase 4 would be R4A.

d. Wireless in pavement sensors use the same numbering scheme as induction loops,
but add a “W” suffix. For example, the phase 7 stop line sensor would be 711W.

e. Exhibit 1330-6 shows examples of standard detector numbering.

11. Emergency vehicle detectors use letter designations: Channel A detectors cover phase 2 and
phase 5; Channel B detectors cover phase 4 and phase 7; Channel C detectors cover phase 1
and phase 6; and Channel D detectors cover phase 3 and phase 8. When there are multiple
detectors for the same channel, the first detector uses the letter, and all other detectors use
a number suffix (C, C1, C2, etc.).

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Exhibit 1330-6 Detector Numbering Examples

1330.04(3) Vehicle Signal Displays

Signal displays are the devices used to convey right of way assignments and warnings from the
signal controller to the motorists and pedestrians. When selecting display configurations and
locations, the most important objective is the need to present these assignments and warnings
to the motorists and pedestrians in a clear, concise, and uniform manner.

The use of ball, steady arrow, or flashing yellow arrow displays is dependent upon the signal
phasing. Use the approved signal phasing diagram to determine which display types can be used
for which movements. Typical vehicle signal displays are shown in Exhibits 1330-7a through 7h.
In addition to the display requirements contained in the MUTCD, the following also apply:
1. A minimum of two indications for the through movement, if one exists at an intersection,
must be provided - even if it is not the primary (predominant) movement. Provide a
minimum of two indications for the major signalized turn movement of an intersection if no
through movement exists, such as on the stem of a T intersection. These signal faces are to
be spaced a minimum of 8 feet apart. At a T intersection, select the higher-volume
movement as the primary movement and provide displays accordingly.
A green left-turn arrow on a primary display and a green ball on the other primary display
do not comply with this rule. At an intersection where left turns are prohibited, the leftmost
through display may use a green up arrow in place of the green ball display. At an

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intersection where right turns are prohibited, the rightmost through display may use a
green up arrow in place of the green ball display.
2. All displays for an approach, regardless of phase served, are to be a minimum of 8 feet
apart.
3. Locate displays directly overhead and centered over the associated lane of the applicable
vehicular traffic as it moves through the intersection. (See Exhibits 1330-7a through 7h for
signal head locations.) For intersections with a skew for through traffic, locate signal displays
for through traffic in one of the following ways:

a. Over the center of the outbound (far side) lane

b. Over a line drawn between the center of the approaching lane and the center of the
associated outbound lane, ending at the stop lines

Left turn displays may either be located relative to the through displays or in line with
approaching traffic, dependent on ability to mount the display(s). (See Exhibit 1330-8 for
skew placement examples.)
4. Locate displays a minimum of 50 feet and a maximum of 180 feet from the stop line. The
preferred location of the signal heads is between 60 and 120 feet from the stop line. When
the nearest signal face is located between 150 and 180 feet beyond the stop line,
engineering judgment of conditions, including worst-case visibility conditions, is to be used
to determine whether the provision of a supplemental or nearside signal face would be
beneficial. When it is not physically possible to locate displays at least 50 feet from the stop
line, the distance to the displays may be reduced as follows:

a. 3-section vertical and 5-section cluster (doghouse) displays may be located between
40 and 50 feet from the stop line.

b. 4-section vertical displays may be located between 41 and 50 feet from the stop line.

c. 5-section vertical displays may be located between 45 and 50 feet from the stop line.

The distances listed above are the minimums required to maintain 16.5 feet of clearance
over the roadway with a backplate installed.

Overhead displays should always be located on the far side of the crossing roadway for the
best visibility. Locating overhead displays on the near side of the roadway results in issues
with visibility and driver compliance with stop lines. When an overhead display is located on
the near side of the crossing roadway, the stop line typically has to be pushed back so that
the minimum visibility distance is met. However, this also pushes the stop line back too far
for drivers to see cross traffic, resulting in drivers creeping past the stop line towards the
intersection – especially for turning traffic. This results in both the driver being stopped past
the stop line and being unable to see the signal displays.

For ramp meter signals, place Type RM signal standards and displays at the stop line.
5. Use vertical vehicle-signal display configurations. Horizontal displays are not allowed unless
clearance requirements cannot be achieved with vertical displays or unless they are being
installed at an intersection to match other displays in the intersection. Approval by the State
Traffic Engineer is required for the installation of horizontal displays.

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6. Use 12-inch signal sections for all vehicle displays except the lower display for a post
mounted ramp meter signal.
7. Provide displays for turning movements with dedicated lanes as follows:

a. For protected movements, use all arrow displays.

b. For protected / permissive movements, use four section arrow displays. Alternatively,
a shared five section cluster (doghouse) display may be used for both the turn lane
and the adjacent through lane. Note: A three section arrow display, with bi-modal
flashing yellow arrow / steady green arrow may be used in cases where windload or
vertical roadway clearance will not allow for the use of a four-section display. If
vertical clearance can be accommodated through adjustments to the signal display
mount, such as mounting the Type M mount between different display sections, a
four section arrow display should be used.

c. For permissive right turns, a three-section arrow display with flashing yellow arrow
(Exhibit 1330-7g) is optional. This display is highly recommended where there are
concerns regarding permissive right turns and the conflicting pedestrian crossing
movement, such as known incidents or high volumes of both pedestrian crossings and
right turn movements.
8. Use steady green arrow indications only when the associated movement is completely
protected from conflict with other vehicular and pedestrian movements. This includes
conflict with a permissive left-turn movement. At T intersections, steady green arrow
displays may not be used for a movement that has a conflicting pedestrian movement.
9. Use either Type M or Type N mountings for vehicle display mountings on mast arms, as
directed by the region maintenance staff or owning agency. Provide only one type of
mounting for each signal system. Mixing mounting types at an intersection is not acceptable
except for supplemental displays mounted on the signal standard shaft.
10. Use backplates for all overhead-mounted displays for new, updated, or rebuilt signal faces.
Add backplates to all existing signal displays that do not already have them.
11. Use Type E mountings for pedestrian displays mounted on signal standard shafts unless
otherwise approved by region maintenance staff or the owning agency.
12. Include supplemental signal displays when the approach is in a horizontal or vertical curve
and the intersection visibility requirements of this section and the MUTCD cannot be met,
unless approved otherwise by the region Traffic Engineer.

Supplemental far side displays are recommended at intersections with higher truck volumes,
as the trucks will frequently block visibility of overhead displays for following drivers.
Supplemental far side protected left turn displays are recommended for long left turns.

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Exhibit 1330-7a Signal Display Placements – Key to Diagrams

Pavement markings are used to

represent possible lane lines and
vehicular movements.
The lane lines shown are typical,
but not necessarily required.

All signal mounts must be a

minimum of 8 feet apart,
measured center to center.
This example shows typical mount
locations for a single approach
lane.

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Exhibit 1330-7b Signal Displays for Single Lane Approach

Single lane approach with

permissive (or no left turns).
R10-12 sign optional.
Where left turns are prohibited,
install a 30” x 30” R3-2 No Left
Turn (Symbol) Sign in place of the
R10-12 sign shown here.

Single lane approach with

protected / permissive left
turns.
R10-12 sign required.

Single lane approach with

protected left turns.

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Exhibit 1330-7c Signal Display Mounting Locations for Multi-Lane Approaches

Single through lane with left turn

lane(s).
Through lane displays arranged
the same as for a single lane
approach.
Left turn display(s) centered over
lane(s).

Multiple through lanes.

Center displays over each lane.

Single through lane with right

turn lane(s).
Through lane displays arranged
the same as for a single lane
approach.
Ensure that the 8-foot spacing
requirement is met if a right
turn display is installed
overhead.

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Exhibit 1330-7d Signal Displays for Dedicated Left Turn Lanes

Dedicated left turn lane with

permissive left turns.
R10-27 (Modified) sign optional.

Dedicated left turn lane with

protected / permissive left turns.
R10-27 (Modified) sign optional.

Dedicated left turn lane with

protected left turns.

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Exhibit 1330-7e Signal Displays for Shared Through-Left Lanes – Multiple Through Lanes

Shared through-left lane with

permissive left turns.
R10-12 sign optional.

Shared through-left lane with

protected / permissive left
turns.
R10-12 sign required.

Shared through-left lane with

protected left turns.

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Exhibit 1330-7f Signal Displays for Shared Through-Right Lanes

Single shared through-right

lane with permissive right
turns.

Shared through-right lane,

multiple through lanes, with
permissive right turns.

Shared through-right lane,

multiple through lanes, with
protected right turns.
For protected / permissive
right turns, mirror protected /
permissive left turn display
from Exhibit 1330-7e.

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Exhibit 1330-7g Signal Displays for Dedicated Right Turn Lanes

Dedicated right turn lane with

permissive right turns.
R10-27 (Modified) sign optional.

Dedicated right turn lane with

protected / permissive right turns.
R10-27 (Modified) sign optional.

Dedicated right turn lane with

protected right turns.

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Exhibit 1330-7h Signal Displays for Multiple Turn Lanes

Multiple left turn lanes.

R3-5L signs optional.

Multiple left turn lanes, with a

shared through-left lane.
R3-5L and R3-6 signs optional.
Mirror for right turns.

Multiple right turn lanes.

R3-5R signs optional.

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Exhibit 1330-8 Example Signal Display Placement for Skew Intersection

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The minimum mounting height for overhead signal displays is 16.5 feet from the roadway
surface to the bottom of the signal housing, including the backplate. There is also a maximum
height for signal displays allowed by the MUTCD, since the roof of a vehicle can obstruct a
motorist’s view of a signal display. The maximum heights from the roadway surface to the
bottom of the signal display housing with 12-inch displays are shown in Exhibit 1330-9.

Exhibit 1330-9 Signal Display Maximum Heights

Maximum Height
Distance to Signal Display (to bottom of display
Stop Line (ft) Arrangement
housing [3])
40 [1] Vertical 3-section 17.5 ft
42 [1] Vertical 4-section 17.0 ft
45 [1] Vertical 5-section [2] 17.0 ft
Vertical 3-section 22.0 ft
53 to 180 Vertical 4-section 20.8 ft
[2] 19.6 ft
Vertical 5-section
Notes:
[1] Minimum distance required to achieve 16.5 feet of clearance with backplate
installed.
[2] For 5-section cluster displays, use the Vertical 3-section heights.
[3] Subtract 0.5 ft for height to bottom of backplate.

At signalized intersections with railroad preemption, install blankout signs for turning
movements that do not have a dedicated signal display (3-section arrow display). Blankout signs
are 36” x 36” and will display either a No Right Turn symbol (R3-1) or No Left Turn symbol (R3-2)
when activated, as appropriate. Blankout signs should be placed the same as equivalent static
signs.

1330.04(4) Pedestrian Equipment

Pedestrian equipment consists of pedestrian signal displays and pedestrian detectors
(pushbuttons). New signal systems are required to use countdown displays and Accessible
Pedestrian Signal (APS) pushbuttons. See 1330.04(4)(a) for pedestrian display and detection
requirements for existing signal systems. No intersection may have a mix of APS and non-APS
pushbuttons, nor may any intersection have a mix of countdown and non-countdown
pedestrian displays.

Pedestrian displays are required to be installed with the bottom of the display housing no less
than 7 feet or more than 10 feet above the sidewalk surface. Pedestrian displays are required to
be installed to provide maximum visibility at the beginning of the controlled crosswalks. To
accomplish this, pedestrian displays should be located no more than 5 feet from the outside
edge of the crosswalk, as measured on a line perpendicular to the crosswalk centerline (See
Exhibit 1330-10). The offset distance may be offset up to a maximum of 10 feet from the outside
edge of the crosswalk if physical constraints prevent the display from being placed no more than
5 feet from the outside edge of the crosswalk.

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Exhibit 1330-10 Pedestrian Display Placement Requirements

Pedestrian pushbuttons (PPBs) are required to be located within a certain distance of the
crosswalk being served and oriented such that the sign on the pushbutton is parallel to the
crosswalk served. Pedestrian pushbutton location requirements are as follows:
 The PPB should be between 4 and 6 feet from the face of curb, where sidewalk is
present, or the edge line of the roadway where there is no sidewalk. The PPB may be
between 1.5 and 4 feet from the curb face or edge line, but this is not recommended
due to proximity to the roadway. The PPB may not be closer than 1.5 feet from the
curb face or edge line. If geometric constraints make it impractical to place the PPB
within the 4-6 foot range, the PPB should not be further than 10 feet from the edge of
curb, shoulder, or pavement. Contact the HQ Traffic Office if the PPB cannot be placed
within 10 feet of the curb face or edge line.
 The PPB should be located as close to the outside edge of the crosswalk line as
possible, so that for APS PPBs, the button and sign face towards the core of the
intersection, rather than back down the adjacent approaching roadway. The PPB may
be located no more than 5 feet outside either edge of the crosswalk line.
 If possible, PPBs should be located on separate poles and be separated by a minimum
of 10 feet.
 See Exhibit 1330-11 for recommended and allowed PPB placement locations.

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Exhibit 1330-11 PPB Placement Requirements

PPBs are required to be located so that the actual button, not just the assembly, is within 9
inches horizontally of a level all-weather surface (generally sidewalk or paved road shoulder) as
described in Chapter 1510. To accomplish this, certain criteria must be met depending on the
type of pole upon which the pushbutton is installed:

a. For vertical shaft poles (Type PPB, PS, I, FB, or RM), the center of the pole shall be no more
than 9 inches from the edge of the level clear space. The pushbutton shall not be oriented
more than 90 degrees from facing the level clear space. (See Exhibit 1330-12a.)

b. For larger signal standards (Type II, III, IV, IV, or SD), the button must face the level clear
space, with the edge of the pole baseplate no more than 6 inches from the edge of the
level clear space. It is recommended that the pole either be in the sidewalk, or the edge
of the pole base plate be installed as close to the back of sidewalk as possible. (See Exhibit
1330-12b.) Some minor rotation of the button on the pole is possible, but even smaller
angles may quickly exceed the allowed reach limit – particularly on larger poles.

Exhibit 1330-12a PPB Placement on Vertical Shaft Poles

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Exhibit 1330-12b PPB Placement on Large Signal Standards

In all cases, it is recommended that the pole be installed in the sidewalk for maximum
accessibility. However, the pole and the pushbutton itself are obstructions and must not
encroach upon the required minimum pedestrian access route widths (see Chapter 1510).

PPBs are required to be installed at 42 inches above the level clear space, as measured to the
center of the actual button. Existing pushbuttons do not require a height adjustment if the
center of the actual button is within a range of 36 to 48 inches above the level clear space.

Where there is a median or center island with a pedestrian refuge, consult with signal
operations to determine if a pushbutton should be installed in the pedestrian refuge area. This
may be justified for locations with particularly long crossings or slower moving pedestrians.

For WSDOT owned systems, pedestrian signal equipment may not be installed on light
standards. Do not install pedestrian signal equipment on light standards for systems owned by
other jurisdictions unless directed to do so by that jurisdiction.
1330.04(4)(a) Accessible Pedestrian Signals and Countdown Pedestrian Displays

Accessible Pedestrian Signals consist of a pedestrian pushbutton with integrated vibro-tactile

and audible versions of the visual indications presented by pedestrian signal displays. APS are
required at any location with a pedestrian display – even if there was no pedestrian detection
previously. This is due to the requirement to provide non-visual indication of the pedestrian
phase. All new construction traffic signals are required to include APS.

Countdown pedestrian displays are displays which use a combination of an overlapping person
(walk) and hand (don’t walk) indication and an adjacent two digit countdown timer display. The
timer counts down the seconds remaining in the pedestrian clearance phase (flashing don’t
walk). For WSDOT owned traffic signals, all new construction traffic signals are required to
include countdown pedestrian displays. For new construction traffic signals owned by other
jurisdictions, countdown pedestrian displays are required unless directed otherwise by the
owning jurisdiction.

For existing signalized intersections where pedestrian equipment was not previously installed,
the installation of APS and countdown pedestrian displays is required for the entire intersection.
This may require new or relocated poles, as well as additional ramp and sidewalk work beyond
that necessary for basic sidewalk and ramp ADA compliance.

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At signalized intersections with existing pedestrian equipment, the following criteria determine
when APS pushbuttons and countdown pedestrian displays shall be installed:
1. The following are considered minor signal upgrades, and do not require the installation of
APS pushbuttons or countdown pedestrian displays at that intersection:
a. Where pushbuttons are only being adjusted in height or orientation.
b. Where pushbuttons are being relocated on a single corner, including to a new pole,
and no other work (including sidewalk or ramp work) is taking place at any other
corner, pushbuttons may be relocated or replaced with the same type of
pushbutton as currently exists at that intersection. Countdown pedestrian displays
are not required to be installed at that intersection. New pole location(s) must meet
accessibility requirements for pedestrian pushbuttons (see Chapter 1510.12).
Accessibility for any affected poles must be evaluated for both existing pushbuttons
and future APS pushbuttons.
2. The following types of work shall include the installation of APS pushbuttons and
countdown pedestrian displays as described below:
a. At any signalized intersection included in a project that is designated as an
alteration project, as defined in Chapter 1510.05(2):
i. For WSDOT owned traffic signal systems, install APS pushbuttons and
countdown displays. For any project which has completed its scoping phase
before August 1, 2018, consult with your ASDE to determine if APS
pushbuttons and countdown pedestrian displays can be added to the
project – documentation is not required if the project cannot support the
expanded scope of work.
ii. For traffic signal systems owned by other agencies, install APS pushbuttons
and countdown displays if funded by the owning agency.
b. At any signalized intersection where APS pushbuttons are being installed in
response to a public request, replace all pushbuttons and pedestrian displays with
APS pushbuttons and countdown pedestrian displays at that intersection. Additional
poles may be required and ramp and sidewalk work may be necessary to support
access to new APS locations / orientations.
c. For any other project, not previously described, which requires traffic signal system
work affecting pedestrian pushbuttons, replace all pushbuttons and pedestrian
displays with APS pushbuttons and countdown pedestrian displays. This may require
additional ramp and sidewalk work to provide required accessibility to and for APS
locations / orientations beyond that already required for other ADA compliance
efforts.

APS pushbuttons are required to include the following features:

1. Audible and vibrotactile indications of the WALK interval.
2. A locator tone which operates only during the DON’T WALK and flashing DON’T WALK
intervals.
3. A tactile arrow on the pushbutton (control surface) indicating the crossing direction served.
This arrow must be high contrast with the rest of the button – either light on dark or dark on
light.

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4. An integral 9” x 15” R10-3e sign.

5. If additional crossing time will be provided as part of an extended press feature, a
supplemental R10-32P sign is required to be installed adjacent to or integral with the APS
PPB.

1330.04(5) Signal Standards (Supports)

Signal standards consist of five main types of supports: Vertical Steel Shaft, Cantilevered Steel
Mast Arm, Steel Strain Pole, Wood Strain Pole, and Signal Bridge. The type of support selected
will depend on required placement of vehicle signal displays and the ability of the support to
reach that location. The MUTCD states that the preferred location for signal displays is overhead
on the far side of the intersection.

Signal displays may also be mounted to bridges where clearance will not allow an alternate
signal standard type. Installation on bridges requires approval of both the region Traffic
Engineer and the HQ Bridge and Structures Office.

Signal Standards shall be considered in the following order of preference:

1. Cantilevered Steel Mast Arm. These are the standard support type for permanent systems,
and should be used whenever possible. Mast arm installations are preferred because they
generally provide better placement of the signal displays, greater stability for signal displays
in high-wind areas, and reduced maintenance costs. Mast arm lengths are limited to 65 feet
from center of pole to farthest display mount – if additional length is needed, an alternate
support type must be used.
2. Span Wire System (Steel or Wood Strain Poles). These systems may be used when displays
are needed at a greater distance than a mast arm system can support, or if a system is
expected to be in place for less than 5 years. Steel poles are required to be used for
permanent signal systems. Temporary signal systems (systems to be removed under the
same contract as installation) may use wood poles. The use of wood poles beyond the end
of a contract or for longer than 5 years requires the approval of the region Traffic Engineer.
Individual spans have a limit of 150 feet – longer spans require design by the HQ Bridge and
Structures Office.
3. Signal Bridge. Signal bridges shall only be used when no other alternative can physically be
installed and support displays in the required locations. Diagonal signal bridges are not
recommended as they are extremely difficult to maintain and result in displays being too
close to at least one of the two cross streets, resulting in poor display visibility. Diagonal
spans in general are not recommended as a failure will result in the loss of the entire signal
system, rather than just one or two directions.
4. Vertical Steel Shaft. Vertical steel shaft supports should only be used for supplemental
vehicle displays or pedestrian equipment. In special cases (such as in a small historic town),
vertical steel shaft supports may be used without overhead signal displays if approved by
the region Traffic Engineer, as allowed by the MUTCD. This practice is not recommended, as
displays are too easily obstructed from view.

When placing signal standards, the primary consideration is the visibility of signal faces. Place
the signal supports as far as feasible from the edge of the traveled way without adversely
affecting signal visibility. (The MUTCD provides additional guidance on locating signal supports.)
Initially, lay out the location for supports for vehicle display systems, pedestrian detection

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systems, and pedestrian display systems independently to determine the optimal location for
each type of support. Consider the need for future right-turn lanes or intersection widening
when choosing the final location of the signal standards. Poles should also be located outside of
sight triangles for turning traffic.

If conditions allow and optimal locations are not compromised, pedestrian displays and
pedestrian detectors can be installed on the vehicular display supports. However, pole
placement cannot encroach on pedestrian access route or maneuvering space requirements.
Pole mounted appurtenances, such as pushbuttons, terminal cabinets, and displays, need to be
taken into consideration regarding their encroachment into accessible spaces.

Another important consideration that can influence the position of signal standards is the
presence of overhead and underground utilities. Verify the location of these lines during the
preliminary design stage to avoid costly changes during construction:

a. Underground Utilities: Underground utilities must be located, marked, and surveyed. If

any underground utility is within 10 feet of any foundation, consider potholing for the
utility to find its actual location. Field locates are rarely precise and must be verified if a
potential conflict exists.

b. Overhead Utilities: Signal standards may be located within close proximity to overhead
communications lines (phone, cable, fiber-optic), but the lines should not touch the any
part of the signal system and should not pass in front of any displays. Overhead power
lines require a minimum 10-foot circumferential clearance for lines rated at 50kV (50,000
V) or below, including the neutral. For lines rated over 50kV, the minimum clearance is 10
feet plus 0.4 inches for each kV over 50kV. Overhead utilities may have to be relocated if a
suitable location for signal equipment cannot be found.

Once pole locations have been selected, a soils investigation is required to determine the lateral
bearing pressure, the friction angle of the soil, and whether groundwater may be encountered.
Standard foundations may be used if the soil lateral bearing pressure is at least 1,000 psf, the
friction angle is at least 17°, and the ground slope is 2H : 1V or flatter. Standard foundation
information is found in the Standard Plans, and depends on the type of support system being
used.

Special foundation designs are required if the soil lateral bearing pressure is less than 1,000 psf,
the friction angle is less than 17°, or the ground slope is steeper than 2H : 1V. The region
materials group works with the HQ Materials Laboratory to determine the bearing pressure and
friction angle of the soil at the proposed foundation locations. If soils do not meet these
minimum values for lateral bearing pressure and friction angle, the signal standard charts and
soil conditions report (summary of geotechnical conditions for foundations) must be forwarded
to the HQ Bridge and Structures Office with a request for special foundation design. The HQ
Bridge and Structures Office designs foundations for the regions and reviews designs submitted
by others.

Where poles are installed on structures, the anchorage must be designed by the Bridge
designer. Coordinate with the Bridge designer for placement and design of pole anchorages on
structures.

Do not place any signal standard in a median area. The sole exception is a Type PS or Type PPB
signal standard as required for median refuge areas for pedestrians.

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Coordinate with all stakeholders (Maintenance, Signal Operations, Civil Design Engineer,
Drainage Engineer, and so on) in the placement of signal equipment to avoid any possible
conflicts. Arrange field reviews with the appropriate stakeholders as necessary.
1330.04(5)(a) Mast Arm Signal Standards and Foundation Design

Mast arm signal standards are designated by the following types:

 Type II: Single mast arm with no luminaire mount.
 Type III: Single mast arm with luminaire mount.
 Type SD: Double mast arm, with or without luminaire mount.

Mast arm signal standards are normally located on the far right corner of the intersection from
approaching traffic. A typical mast arm signal standard only has one mast arm, however two
may be used. If the angle between the two arms is not exactly 90 degrees, the design must be
sent to the bridge and structures office. In most cases, two arms at 90 degrees can support the
necessary display positioning. Additionally, signal standards on mast arms may be rotated up to
30 degrees from center. Do not allow a mast arm for one direction to cross in front of the mast
arm for a different direction if possible, as it results in a visual obstruction of the signal displays.
Where two double arm signal standards are installed on opposite corners, the preferred
location for the two poles are the far right corners of the mainline roadway. This way, the mast
arms for the mainline traffic will not cross in front of each other.

Mast arm signal standards have a typical arm attachment point of 18 to 20 feet in height. This
height range needs to be taken into consideration when placing signal displays in order to
ensure that the display height requirements shown in 1330.04(3) are met. The attachment point
height may be adjusted throughout this range as necessary, but increments of 0.5 feet are
recommended for ease of fabrication. Connection points outside of this range are a special
design, and require design support from the Bridge and Structures Office.

Mast arm signal standards are designed based on the total wind load moment on the mast arm.
The moment is a function of the surface area of each appurtenance (signal display or sign), X * Y,
and the distance between the vertical centerline of each appurtenance and the vertical
centerline of the signal pole Z. This determines the total wind load moment, referred to as an
XYZ value and measured in cubic feet, which is used to select the appropriate mast arm
fabrication plan and foundation design. Preapproved mast arm fabrication plans are available at
http://www.wsdot.wa.gov/Bridge/Structures/LSS.htm, and will be listed in the Contract
Provisions. To determine the XYZ value for a signal standard, the XYZ value of each
appurtenance must be calculated. These values are then totaled to determine the overall XYZ
value for the signal standard. For signal standards with two mast arms at 90 degrees apart, the
larger of the two XYZ values calculated for each mast arm is used for the overall pole XYZ value.

When determining the XYZ values, use the worst-case scenarios for signal display and sign
placements. All signal displays and mast arm-mounted signs, including street name signs, must
be included in this calculation. Emergency preemption detectors, preemption indicator lights,
cameras, and radar detectors are negligible and are not included in determining the XYZ values.
For mast arm-mounted signs, use the actual sign area (in square feet) to determine the XYZ
value. For poles with luminaire supports, the luminaire and arm is also included in the total XYZ
calculation. Surface areas for vehicle displays are shown in Exhibit 1330-13. Signs are limited in
size as follows:

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 Street name signs may be a maximum of 36 inches in height and 36 square feet in total
area. Design the mast arm to support the widest sign that will fit within these limits (up
to 144 inches wide), regardless of the actual sign size needed. This allows for future
changes to the street name sign. Street name signs are mounted such that the edge of
the pole is no less than 1 foot but no more than 2.5 feet from the vertical pole
centerline, as shown in the Standard Plans. Use the offset necessary for the largest
possible sign in the signal standard chart for the XYZ value, but refer to the Standard
Plans for actual sign installation requirements using construction notes in the Contract
Plans.
 Other mast arm mounted signs may not exceed 36 inches in height and 7.5 square feet
in area.
 Signs mounted on the vertical pole may not exceed 36 inches in width and 15 square
feet in area. These signs are not included in the XYZ calculation.

After calculating the total XYZ value, adjust the total XYZ value as follows:

If the total XYZ value is less than or equal to 2850 ft3, round the XYZ value up to the next
standard foundation XYZ value or 2850 ft3, whichever is lower, to determine the design XYZ
value. The design XYZ builds in some flexibility for future modifications.

 If the total XYZ value exceeds 2850 ft3, use the calculated XYZ value. There is limited
opportunity for future increased wind load when the XYZ value exceeds 2850 ft3.

Exhibit 1330-13 Signal Display Surface Areas

Signal Display Area

Vertical 3-section 9.2 sq ft

Vertical 4-section 11.6 sq ft
Vertical 5-section 14.1 sq ft
5-section cluster 14.4 sq ft

After the total XYZ value is determined, if a standard foundation may be used, select the correct
foundation depths for the XYZ values from the table in the Standard Plans, using the next higher
total XYZ value. For WSDOT systems, only the 700, 1350, 1900, 2600, and 3000 columns may be
used. All five foundation options should be provided unless there is a known constraint
preventing the use of one of the options, such as insufficient space for 4 ft diameter foundation
or expected loose soil requiring the use of the Alternate 2 foundation construction.

1330.04(5)(b) Span Wire Signal Standards and Foundation Design

Span Wire Systems use poles and aerial wires to support signal displays, signs, and emergency
preemption equipment. Cameras, radar detectors, and street name signs are installed on the
vertical strain poles. When laying out span wires, the preferred layout is similar to mast arm
supports. Displays for an approach should be installed on a span on the far side of the
intersection, with poles on the two far corners. Do not use diagonal spans unless absolutely
necessary, as they are extremely difficult to maintain and if the wire is broken, the entire signal

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system is lost and blocks the entire intersection, rather than the equipment for only one
approach.

Span wire signal standards include both steel and timber strain poles. Steel and timber strain
poles are designated by pole class, which is based on the horizontal tension load the pole will
support. The loads and resultant forces imposed on strain poles are calculated and a pole class
greater than that load is specified. Steel Pole Classes and their allowed tension loads are listed in
the Standard Plans. Exhibit 1330-14 lists the pole classes and tension loading available for
timber strain poles.

Headquarters Traffic and Headquarters Bridge and Structures office support is required for
determining span tension load and pole classes. Provide the pole and span layout, the locations
and sizes of all signal displays and span wire mounted signs, and the soils report. Span wire
mounted signs are limited to a maximum of 36 inches in height and 7.5 square feet in area.
Emergency preemption equipment locations do not need to be submitted, as they are not
included in load calculations. Spans should not exceed 150 feet, if possible, in order to reduce
the complexity of the design.

After the pole classes are provided by the Headquarters Bridge and Structures office, select the
appropriate foundation information from the Standard Plans using the pole classes and soil
conditions. If a standard foundation cannot be used, a foundation design will be provided along
with the pole class information.

Exhibit 1330-14 Timber Strain Pole Classes

Tension Load
Pole Class
Limit (lbs)
4 2400
3 3000

2 3700
1 4500

H1 5400

H2 6400

H3 7500

Pole Classes from ANSI Standard O5.1

1330.04(5)(c) Special Case Signal Supports

Special case signal supports include signal bridges and structure (typically bridge) mounts. These
should only be selected if absolutely necessary, as they are difficult to design, construct, and
maintain, and they frequently result in signal display locations that are difficult for drivers to
see. Use of these types of supports requires approval from the Headquarters Traffic Office.

Signal bridges function the same as a diagonal span wire system, with the two supports on
opposite corners of the intersection. Signal bridges require windload calculations similar to mast

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arm signal standards, so display and sign locations and offsets must be provided. Signal bridge
foundations must be designed by the Headquarters Bridge and Structures office.

Signal displays and other equipment may be installed on structures when there is insufficient
clearance below the structure to allow for a different type of signal support. Coordinate with the
Bridge designer to place mounts and determine routing paths for conduit and wiring out of the
structure. Structure mounts are not desirable, as they typically cannot be modified without
reconstruction of the structure itself, and any equipment embedded in the structure is
inaccessible after the structure is complete.

Signal displays may not be installed on sign structures such as cantilever sign structures or sign
bridges. Signal displays also may not be installed on railroad cantilever structures unless the
signal system and the railroad are owned by the same jurisdiction and maintained by the same
staff.

1330.04(5)(d) Vertical Steel Shaft Supports

Vertical steel shaft supports include the following types of signal standards:

(a) Type PPB: Sometimes referred to as a “stub pole”, this pole is typically 5 feet tall and 3
inches in diameter. It is used strictly to support pedestrian pushbuttons. Due to the
frequency of damage, regardless of location, it is recommended that breakaway bases
always be used.

(b) Type PS, I, RM, and FB: These poles are effectively identical, with the difference being
the total height to the slipfitter top.
 Type PS are 8 ft tall and may only have pedestrian displays mounted on the
top.
 Type I are 10 ft tall and may have vehicle displays mounted on the top and
pedestrian displays mounted on the side. Type RM are identical to Type I but
are used for ramp meter systems only.
 Type FB are 14 feet tall, and may be used like Type I when additional height is
needed for the vehicle display(s).

Placement of vertical steel shaft supports will depend on visibility requirements for displays and
accessibility requirements of pedestrian features. Generally, these supports should be located at
back of sidewalk, as they are farther from traffic and more likely to be out of both the
pedestrian access route and the path of any users. Fixed bases should be used when located at
the back of sidewalk, but slip bases may be used if circumstances recommend it. Supports
located within sidewalk (includes planter strips) or in locations with only paved shoulders should
always use slip bases.

1330.04(6) Vehicle Detection Systems

Vehicle detection systems are necessary for the efficient operation of traffic signals. By
responding to the presence of traffic, signal systems do not have to use fixed timing. This
improves efficiency by removing unnecessary delay and not providing service to an approach or
movement with no traffic.

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1330.04(6)(a) Vehicle Detection Zone Placement

The detection system at a traffic-actuated signal installation provides the control unit with
information regarding the presence or movement of vehicles, bicycles, and pedestrians. Vehicle
detection systems perform two basic functions: queue clearance and the termination of phases.
Depending on the specific intersection characteristics, either of these functions can take
priority. The merits of each function are considered and a compromise might be necessary.

There are two basic types of detection zones: stop bar and advance. Stop bar detection is a zone
that extends from the stop line to a point 30 to 40 feet in advance of that location. Advance
detection is a discrete zone (or zones) placed in advance of the stop line at a distance dependent
on vehicle speed.

Basic vehicle detection requirements depend upon the speeds of the approaching vehicles:

(a) When the posted speed is below 35 mph, provide stop bar detection or one advance
detection zone. See Exhibit 1330-15 for advance detection zone distances.

(b) When the posted speed is at or above 35 MPH, provide stop bar detection and at least
two advance detection zones. Multiple advance detection zones are normally required to
accommodate decision zone detection.

(c) Side street advance detection is not required for WSDOT owned signal systems, but may
be provided through means that do not require equipment to be installed off of WSDOT
right of way. For signals owned by other jurisdictions, the use of side street advance
detection is at the discretion of the owning jurisdiction.

A decision zone is a location along the intersection approach where a motorist is forced to make
a decision between two alternatives. As applied to vehicle detection design, this situation can
occur when two vehicles are approaching a traffic signal and the signal indication turns yellow.
The motorist in each vehicle must decide whether to continue through the intersection or stop
prior to the intersection. If the lead vehicle decides to brake and the following vehicle does not,
there may be a rear-end crash.

For posted speeds of 35 MPH or higher, there are two options for placing advance detectors to
address the decision zone:
1. Fixed locations based on posted speed, which is generally the 85th percentile speed. Place
loops according to the table in Exhibit 1330-15.
2. Calculated locations based on calculated decision zone detection design. This design
increases the opportunity for a range of vehicles from the 90th percentile speed vehicle to
the 10th percentile speed vehicle to either clear the intersection or decelerate to a
complete stop before reaching the intersection. The method of calculating the decision zone
and the required detection loops is shown in Exhibit 1330-16.

Although the exhibits reference loops, advance detectors may be of any approved type.

For new intersection construction where there is no existing traffic, the fixed locations based on
posted (target design) speed are to be used. Fixed locations based on posted speed use the
same methods as the calculated decision zone detection design, but set V90 at 5 MPH above
posted speed and V10 at 5 MPH below posted speed. Engineering judgment based on similar
intersections (such as geometrics and traffic volumes) may justify modifying the V90 and V10
speeds used in the calculation, with concurrence from the region Signal Operations Engineer.

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Both methods require a study of the approach speeds at the intersection. For intersection
approaches, conduct the speed study as follows:
 Collect data at the approximate location or just upstream of the decision zone;
 Collect data during off-peak hours in free-flow and favorable weather conditions;
 Collect data during regular commuting hours in a high volume signalized corridor
during favorable weather conditions
 Only document the speed of the lead vehicle in each platoon.

It is important that the person conducting the speed study remain inconspicuous so they do not
influence drivers to slow down. Normal driving patterns are needed for proper speed studies.
Prior speed-study information obtained at this location may be used if it is less than 18 months
old and driving conditions have not changed significantly in the area.

Preserve detection zone placements and any supporting calculations as required by 1330.07
Documentation.

Exhibit 1330-15 Fixed Vehicle Detection Placement

Fixed Detection Placement – Below 35 MPH Calculated Rounded

V85 = V90 = V10 = UDZ90 DDZ10 LC1 PMID LC2 Loop 1 Loop 1
MPH ft/s MPH ft/s MPH ft/s ft ft s ft s ft ft
25 36.7 30 44.00 20 29.33 165.00 50.84 3.9 107.92 1.9 107.92 105
30 44 35 51.33 25 36.67 216.03 70.28 4 143.15 2 143.15 140

For posted speeds below 35 MPH, only the PMID detection location is used.

Fixed Detection Placement – 35 MPH and Above Calculated Rounded

Loop Loop Loop Loop
V85 = V90 = V10 = UDZ90 DDZ10 LC1 PMID LC2
1 2 1 2
MPH ft/s MPH ft/s MPH ft/s ft ft s ft s ft ft ft ft
35 51.33 40 58.67 30 44.00 273.78 92.40 4.1 183.09 2.1 183.09 273.78 180 275
40 58.67 45 66.00 35 51.33 338.25 117.21 4.3 227.73 2.2 227.73 338.25 225 340
45 66 50 73.33 40 58.67 409.44 144.71 4.5 277.08 2.3 277.08 409.44 275 410
50 73.33 55 80.67 45 66.00 487.36 174.90 4.7 331.13 2.4 331.13 487.36 330 490
55 80.67 60 88.00 50 73.33 572.00 207.78 5 389.89 2.5 389.89 572.00 385 575
60 88 65 95.33 55 80.67 663.36 243.34 5.2 453.35 2.6 453.35 663.36 450 665

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Exhibit 1330-16 Decision Zone Detection Placement

Decision Zone Endpoint Calculation

(for all loop arrangements)
Where grades are flatter than +/- 4%:

(V90 )2
UDZ90 = +V90
16

(V10 )2
DDZ10 = +V10
Single Advanced Loop Design UDZ90 -DDZ10 40
LC1 =
Use when LC1 ≤ 3 seconds V10
Where grades are +/- 4% or steeper:

(V90 )2
UDZ90 = +V
2(8+32.2G) 90

(V10 )2
DDZ10 = +V
2(20+32.2G) 10

Double Advanced Loop Design UDZ90 +DDZ10 UDZ90 -PMID

Use when LC2 ≤ 3 seconds PMID = LC2 =
2 V10

Triple Advanced Loop Design

Use when LC3 ≤ 3 seconds

UDZ90 -DDZ10 [2(UDZ90 )+DDZ10 ] [UDZ90 +2(DDZ10 )]

LC3 = PMID1 = PMID2 =
3V10 3 3

Where:
V90 = 90th percentile speed, in feet per second G = Grade of roadway, in decimal form,
V10 = 10th percentile speed, in feet per second including + or – (Example: -4% = -0.04)
UDZ90 = Upstream end of decision zone, LC1 = V10 travel time to DDZ10
for 90th percentile speed LC2 = V10 travel time from UDZ90 to PMID
DDZ10 = Downstream end of decision zone, LC3 = V10 travel time from PMID2 to DDZ10
for 10th percentile speed

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1330.04(6)(b) Vehicle Detector Types

There are two basic categories of vehicle detectors:

 Non-Invasive: These are detectors installed outside of the roadway, typically overhead in a
strategic location. These include camera (optical and infra-red) and radar systems.

 In-Pavement: These are detectors which are installed in the road itself. These include
induction loops and wireless in-pavement sensors.

Non-invasive detection is generally recommended over in-pavement detection, due to the

ability to revise non-invasive detection at any time and the ease of installation, repair, and
replacement – particularly when supporting traffic control and impacts are taken into account.
Additionally, pavement damage due to regular wear or construction activities will disable in-
pavement detection, whereas non-invasive detectors will continue to function, and can even be
adjusted to accommodate revised lane configurations.

Stop line detection should use non-invasive systems for detection. Although induction loop
detectors are typically the most reliable for detecting cars and trucks, they do not consistently
detect bicycles and motorcycles. RCW 47.36.025 specifically requires that vehicle-activated
traffic control signals be capable of detecting motorcycles and bicycles.

Advanced detection may be either non-invasive or in-pavement, as these improve efficiency of

the signal systems but are not as critical as stop line detection. Non-invasive is recommended
for posted speeds of 45 MPH or lower, as they are currently only effective for up to about 600
feet from the location of the detector. The advantage is that advance detection can be installed
at the intersection, rather than trenching long distances to place advanced detectors in
pavement. For speeds over 45 MPH, non-invasive detection systems may be considered, but in-
pavement systems will probably be more effective. Advance detection does not need to detect
bicycles.

Selection of detector types will depend on a variety of environmental factors and locations
available for placement.

1. Radar Detectors

Radar detectors are located on either the signal mast arms or the signal vertical strain poles,
depending on lane configuration, detector type, and location availability. Radar detectors
are not affected by weather, and are typically minimally affected by mast arm motion in
high wind. Consult the detector manufacturer’s installation guidance for placement details.
One detector can normally cover all lanes of an approach for that type of detection (stop
line or advance).

2. Video Detectors

Placement of video detectors depends on the function of the detector. Exhibit 1330-17
provides placement examples.

Stop line detectors should be installed on the same mast arm as the vehicle displays for that
approach. The detector should be placed on an extension of the wide line between the left
turn and through lanes, if present; if there is no wide line, the detector should be centered
on the through lanes. One detector can cover all lanes of an approach for that type of
detection (stop line or advance).

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Advance detectors should be installed on a luminaire arm, preferably on the adjacent corner
to the approaching lanes, as the effectiveness of the advance detection depends on height.
Consider requiring a luminaire arm even if no luminaire is needed, in order to provide an
optimal installation site for the detector. Advance detectors may be installed on a mast arm,
but will typically have less effective range.

Both infra-red and optical cameras are available, but optical cameras are not recommended
due to the adverse effects of rain, snow, fog, sun glare, and sharp shadows on their
effectiveness. However, infra-red cameras may still be affected by heavy fog or other major
thermal events. All video detection may be affected by mast arm motion due to high winds.
Exhibit 1330-17 Video Detector Placement

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3. Induction Loops
Induction Loops are coils of wire in the roadway that use the magnetic properties of vehicles
to detect them. Induction loops can last a very long time when undisturbed. However,
induction loops require bicycles to be in a very specific location in order to be detected, and
may not detect carbon fiber bicycles. Induction loops must be installed with one per lane
per detection zone – stop line loops may be larger or series loops. Where induction loops
are used, loops need to be numbered in order to keep track of the wiring and lanes they are
detecting. See 1330.04(2) for detector numbering requirements.
4. Wireless In-Pavement Sensors
Wireless in-pavement sensors are compact detectors installed in pavement, and use either
radar or magnetics to detect vehicles. They use a wireless connection to the signal cabinet.
The sensors rely on a battery for operation, and require replacement of the entire unit when
they fail. Sensor placement is similar to induction loops – one per lane per detection zone.
The magnetic versions are subject to the same difficulties with bicycles as loop detectors. All
wireless sensors are also subject to various factors that affect wireless signals such as range,
signal obstructions, and possible signal interference from other radios depending on the
frequency used.

Non-invasive detectors are preferred with concrete (Portland cement concrete pavement)
roadway surfaces. In-pavement detectors installed in concrete panels typically cannot be revised
or replaced until all affected concrete panels are replaced. In-pavement detectors installed in
bridge decks must be installed when the bridge deck is constructed, and cannot be replaced
unless the bridge deck is replaced. Non-invasive detection is also useful for approaches where
advance detection is desired, but the approach is outside the jurisdiction of the agency that
owns the signal, or for non-standard approaches such as driveways.

Temporary detection should be installed for all stop lines where existing detection will be
disabled or ineffective (such as lane shifts) during construction. Temporary advance detection is
recommended for high speed (45 MPH or higher) approaches where the decision zone detection
will be disconnected for an extended period of time. Consult with the Signal Operations
Engineer to determine if temporary advance detection should be used. Temporary advance
detection zone placement should take into account any temporary speed limit revisions.

1330.04(7) Preemption Systems

1330.04(7)(a) Emergency Vehicle Preemption

Emergency vehicle preemption (EVP) is required for all traffic signals unless approved otherwise
by the region Traffic Engineer. WSDOT is responsible for installing EVP detection equipment at
new and rebuilt signalized intersections on state highways. At existing signalized intersections
that do not have EVP detection equipment, or where an emergency service agency requests
additional equipment beyond the basic required equipment, the emergency service agency is
responsible for all material and installation costs. The emergency service agency is responsible
for preemption emitters in all cases.

Optically activated EVP systems are used to ensure compatibility with all area emergency service
agency emitters. Approval by the State Traffic Engineer is required for the installation of any
other type of emergency vehicle preemption system.

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Locate optical detectors facing each approach to the intersection – only one detector per
approach – with a clear view of the approaching roadway. Detectors have a cone of vision of
approximately 8 degrees, and an effective range of 200 to 2500 feet. Detectors should have an
unobstructed view of the approach for a minimum of 1800 feet. Primary detectors are normally
installed on the same support as the vehicle displays for that approach. Place the detector
between the left turn lane and through lane displays on approaches with left turn lanes, or
centered on the approaching lanes where left turn lanes are absent.

When the approach is in a horizontal or vertical curve, or there are other sight obstructions,
non-standard placement of the primary detector or additional supplemental detectors may be
necessary. Primary detectors may be located on other signal display supports (arms or spans) or
vertical strain poles, depending on visibility requirements. Supplemental detectors may also be
located on separate Type I or Type FB poles in advance of the intersection. On higher speed
roadways, supplemental detectors can provide extended detection range – one mile in advance
of the intersection is usually sufficient.

Preserve any documentation associated with the EVP system, including system type selected
and any associated agreements or approvals, as required by 1330.07 Documentation.

1330.04(7)(b) Railroad Preemption

Railroad preemption is used when a railroad is in close proximity to a signalized intersection. If

railroad tracks are within 1/4 mile of a signalized intersection, then a Railroad Crossing
Evaluation Team is formed to determine the need (if any) for railroad preemption,
interconnection, simultaneous preemption, advanced preemption, and so on. The Railroad
Crossing Evaluation Team should consist of region and HQ Signal Design Engineers, region and
HQ Signal Operations Engineers, HQ Railroad Liaison, HQ Rail Office representative, region
Utilities Engineer, region Traffic Design Engineer, region Maintenance Superintendent, and the
affected railroad representative. Where the signal is owned, operated, or maintained by a local
agency, a local agency representative should also be included.

The Railroad Crossing Evaluation Team will determine what design considerations are needed at
all signalized intersections near railroad crossings. For locations where the railroad tracks are
located greater than 500 feet from the signalized intersection, and it can be demonstrated that
the 95% maximum queue length(s) will not extend to within 200 feet of the tracks, railroad
preemption may be omitted with the approval of the Railroad Crossing Evaluation Team. Include
the demonstration and approval in the documentation required by 1330.07 Documentation.

Railroad preemption and interconnection are recommended when any of the following
conditions occurs:
 The distance from the stop bar to the nearest rail is less than or equal to 200 feet.
 There is no dedicated left turn lane and the distance from the stop bar to the nearest
rail is less than or equal to 500 feet.
 The 95% maximum queue lengths from the intersection stop bar are projected to cross
the tracks. (Use a queue arrival/departure study or a traffic analysis “micro-simulation
model” to determine 95% maximum queue lengths.)
 The 95% maximum queue lengths from the railroad are projected to affect an
upstream traffic signal. (Use a queue arrival/departure study or a traffic analysis
“micro-simulation model” to determine 95% maximum queue lengths.)

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If it is determined that advanced preemption is needed, the HQ and region Signal Operations
Engineers will calculate the amount of railroad preemption time required using the Guide for
Determining Time Requirements for Traffic Signal Preemption at Highway-Rail Grade Crossings
(TxDOT Form 2304).

The addition of a pre-signal is recommended when any of the following conditions occurs:
 The distance from the stop bar to the nearest rail is less than 88 feet but is at least 40
feet. (For reference, the 88 feet is derived from: the longest design vehicle permitted
by statute (75 feet) + front overhang (3 feet) + rear overhang (4 feet) + downstream
clear storage (6 feet)).
 The distance from the stop bar to the nearest rail is > 88 feet and < 120 feet and there
are no gates for the railroad crossing.
 The sight distance triangle in Chapter 1350, Exhibit 1350-1 (Sight Distance at Railroad
Crossing), cannot be met, and the railroad crossing does not have active control (lights
or gates).

When pre-signals are used, two stop lines are used: one for the rail crossing, and one for the
intersection. The pre-signal displays stop traffic at the rail crossing stop line, and the second set
of signal displays stop traffic at the intersection. Use louvers on the intersection displays so that
they are not visible from the stop line for the rail crossing. Optically programmed displays may
be used in place of louvers, but are not recommended due to the limited benefits, complexity of
installation and maintenance, and high cost.

Where the distance between the normal location for the stop bar and the approach is less than
40 feet, the same stop bar should be used for both the traffic signal and the rail crossing. Install
vehicle displays on the near side of the intersection, but on the far side of the tracks from the
stop line, to improve visibility and discourage drivers from stopping between the tracks and the
intersection. Do not install vehicle displays on the far side of the intersection.

Exhibit 1330-18 shows examples of the distances and typical system layouts referenced above.

The Railroad Crossing Evaluation Team has final review and approval authority for all PS&E
documents for signal design and operation at all signalized intersections near railroad crossings.
All documentation associated with railroad preemption and a memo with each team member’s
concurrence with the PS&E documents must be preserved as required by 1330.07
Documentation.

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Exhibit 1330-18 Signal Display Layout for Rail Crossings

Display Placement
Less than 40 feet between tracks (dynamic envelope marking) and intersection

Display Placement
40 to 88 feet between tracks and intersection

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1330.04(7)(c) Transit Priority Preemption

Transit Priority Preemption allows for transit operations to influence signal timing, similar to
emergency vehicle preemption. This can be included in mobility projects, but the transit agency
assumes all costs for providing, installing, and maintaining this preemption equipment. WSDOT’s
role is limited to approving preemption operational strategies (phasing, timing, software, and so
on) and verifying the compatibility of the transit agency’s equipment with the traffic signal
control equipment. Preserve all transit priority preemption decisions and agreements as
required by 1330.07 Documentation.

1330.04(8) Control Equipment

The standard WSDOT Signal Controller type for traffic signals is the Type 2070 Controller. Some
agencies use National Electrical Manufacturers Association (NEMA) controllers (Type TS1 or
TS2). Although not normally used for new construction, WSDOT Ramp Meters and some older
systems still use Type 170 Controllers. All traffic signal controllers have the following basic
functions:
 Dual ring phase operation
 Eight vehicle phases
 Four pedestrian phases
 Four overlap phases
 Four emergency vehicle preemption channels
 Railroad preemption
 Start and end daylight savings time dates
 Transit preemption (some older controllers may not support this)

Type 2070 controllers and newer NEMA controllers are functionally equivalent for basic signal
operations. However, Type 2070 controllers and NEMA controllers use different operating
software and communications protocols, and therefore cannot be interconnected together. The
type of controller should be specified as follows:
1. For WSDOT traffic signals, specify Type 2070 controllers, unless:

a. The signal is interconnected with other signals. If the other controllers in the
interconnected system are not being replaced, specify a controller (2070, NEMA, or
other) that matches the rest of the interconnected system.

b. The signal is operated by another agency. In this case, work with WSDOT and the other
agency’s maintenance staff to determine the appropriate controller type.
2. For traffic signals owned by other agencies, specify the controller type used by that agency.

The region or operating agency will determine the controller brand and operating software,
which are included in the cabinet specifications. Each region or operating agency will provide
specifications for their cabinets and the equipment contained therein. For 2070 controllers,
double-width cabinets (two racks) should be specified if physically possible to allow for future
communications and ITS equipment.

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It is often beneficial for one of the agencies to assume responsibility for the operation of the
traffic signals. This is accomplished by negotiating an agreement with the other agency. The
designer needs to check region policy and make sure someone initiates the process for setting
up an operational agreement with the other agency or modifying an existing agreement when
applicable. (See the Agreements Manual for more information on signal systems and
maintenance agreements.) At a new intersection, where the state owns the signal, but WSDOT
has agreed to let another agency operate the signal, the controller should be compatible with
that agency’s system. When installing a new controller in an existing interconnected corridor,
the controller should be capable of operating with the existing controllers in the corridor. In
situations where it is necessary to coordinate the traffic movements with another agency, it is
important that the agencies work together.

Intersections within ½ mile of each other on state highways should be interconnected. Perform
an operational analysis to determine need for interconnection where intersections are within 1
mile of each other on state highways with a posted speed of 45 MPH or higher. The preferred
method for interconnection is fiber optic cable, but other methods such as IP over copper or
wireless interconnect may be considered after discussion with maintenance staff and approval
by the region Traffic Engineer. Where fiber optic cable is used, it must be routed through pull
boxes and cable vaults – bending fiber optic cable through standard junction boxes typically
results in the cable being broken. Consider using a separate pull box or vault for coiling the fiber
optic interconnect cable to allow for the large-bend radii. Add a construction note in the plans
stating to coil additional cable in the adjacent pull box or vault, not the controller cabinet. This
will save on space in the controller cabinet and provides additional cable in case an errant
vehicle hits the cabinet.

Coordinate with the operations and maintenance staff to determine the optimum controller
cabinet location and the cabinet door orientation. The controller cabinet is positioned to
provide the best maintenance access and clearest view of the intersection possible. Preferred
visibility allows for as many signal displays and roadway approaches visible as possible from a
single location. Cabinets should not be placed where they might block the view of turning traffic
(intersection sight triangle). If possible, position the controller where it will not be affected by
future highway construction.

Cabinets require a minimum of 36 inches of level space in front of each door, including the
concrete pad. Do not place cabinets where flooding might occur or where the cabinet might be
hit by errant vehicles. If there is a steep down slope or drop off near the cabinet, personnel fall
protection (such as fencing) is required in accordance with standards established by the
Department of Labor and Industries. Fall protection may not encroach on the required clear
space for the cabinet. The location must also have adequate room for a maintenance vehicle to
park near the cabinet. Sufficient space for a bucket truck to park is preferable.

If a telephone line (voice or DSL), fiber optic, wireless, or other connection is desired for remote
access to the equipment in the cabinet, provide the appropriate equipment in the controller
cabinet and/or nearby junction box or cable vault with separate conduits and junction boxes for
the remote communications equipment. Communications connections to outside utilities
require their own separate conduit and box/vault system.

Consult with maintenance and operations staff to determine if a backup power source, such as
an Uninterruptible Power Supply (UPS) or backup generator, is needed for the signal cabinet.
Install the backup power supply on the same concrete pad as the signal cabinet. Service and
other cabinets may also be installed on the same concrete pad as the signal cabinet (see the

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Standard Plans for concrete cabinet pad layouts). Refer to Chapter 1040 for electrical service
types, overcurrent protection, and descriptions and requirements for other components.

1330.04(9) Wiring, Conduit, and Junction Boxes

Consider cost, flexibility, construction requirements, and ease of maintenance when laying out
the electrical circuits for the traffic signal system. Consolidate roadway crossings (signal,
illumination, ITS conduits, and so on) whenever possible to minimize the number of crossings
and take advantage of single crossing construction (joint trenches or consolidated directional
boring). Include all electrical design calculations in the Project File.

1330.04(9)(a) System Wiring

Traffic signal systems use multi-conductor cables to connect most of the equipment. Single
conductor cable is limited to cabinet power and street lighting circuits.

The following describes typical WSDOT wire type selection:

 5c cables for signal displays. One 5c per signal phase may connect the signal cabinet to
the terminal cabinet on the pole. Separate 5c cables should connect each signal display
to the terminal cabinet. Protected / permissive displays may either use one 7c cable or
two 5c cables (one for each phase on the shared display).
 5c cables for pedestrian displays. Consult with region maintenance to determine if the
same 5c cable is used for associated pedestrian detection.
 3cs cables for emergency preemption detectors.
 2c cables for induction loop detectors. Shielded cable is not required for modern loop
detector cards. Older systems may still need shielded cable (2cs), but it is
recommended to replace the loop detector cards instead.
 Manufacturer specified cables for video and radar detectors. Video detectors typically
use a combined RG9/5c (#18) cable. Radar detectors typically use proprietary 6c and 8c
cables. These cables are roughly the size of 7c cables (for calculating conduit fill).
 Use 2c cables for isolated pedestrian detectors (separate pole from associated
pedestrian display). For connecting 4-wire APS units, a 7c cable may be used between
the PPB post and the signal pole with the pedestrian display (where the APS control
unit is located).

To simplify potential repairs for smaller signal standards (Type FB and smaller), consider routing
signal display and detection conductors through terminal cabinets on larger signal standards
(Type II and larger) before connecting to smaller signal standards. This reduces the amount of
wire which may need to be replaced if a smaller signal standard is knocked down and the wiring
damaged.

1330.04(9)(b) Conduit

Refer to the Standard Specifications for conduit installation requirements. At existing

intersections, where roadway reconstruction is not proposed, conduits are to be placed beyond
the paved shoulder or behind existing sidewalks to reduce installation costs. All conduits shall be
a minimum of 2 inches in size, with the following exceptions:

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1. Conduits entering Type PPB signal standards shall be 1 inch. This may be increased to 1 1/4
inch when two APS PPBs are installed on the same pole.
2. Lighting conduits entering pole foundations (signal or light standards) shall be a minimum of
1 inch. See Chapter 1040 for additional requirements for light standards with slip bases.
3. Conduits entering Type PS, I, RM, and FB poles may be a minimum of 1-inch and a maximum
of 2-inch.
4. The conduit for the service grounding electrode conductor may be a minimum of ½-inch.

Install spare conduits at all road crossings. Spare conduits at road crossings should be a
minimum of one 3-inch conduit or two 2-inch conduits. Install a minimum 2-inch (preferably 3-
inch) spare conduit into the controller cabinet.

It is recommended to use full inch conduit sizes to simplify construction and reduce the different
types of conduits required for the system. This helps to provide future capacity and reduce costs
through bulk material purchasing. Size all conduits to provide 26% maximum conductor fill for
new signal installations. A 40% fill area can be used when installing conductors in existing
conduits. (See Exhibit 1330-19 for conduit and signal conductor sizes.)

Exhibit 1330-19 Conduit and Conductor Sizes

Conduit Sizing Table

Inside Diam. Maximum Fill (inch2)
Trade Size
(inches) 26% 40%
1/2" 0.632 0.08 0.13
3/4" 0.836 0.14 0.22
1” 1.063 0.23 0.35
1 1/4" 1.394 0.40 0.61
1 1/2" 1.624 0.54 0.83
2” 2.083 0.89 1.36
2 1/2" 2.489 1.27 1.95
3” 3.09 1.95 3.00
3 1/2" 3.57 2.60 4.00
4” 4.05 3.35 5.15
Conductor Size Table
Size (AWG) Area (inch2) Size (AWG) Area (inch2)
# 14 USE 0.021 2cs (# 14) 0.090
# 12 USE 0.026 3cs (# 20) 0.070
# 10 USE 0.033 4cs (# 18) 0.060
# 8 USE 0.056 5c (# 14) 0.140
# 6 USE 0.073 7c (# 14) 0.170
# 4 USE 0.097 10c (# 14) 0.290
# 3 USE 0.113 6pcc (# 19) 0.320
# 2 USE 0.133

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Minimize roadway crossings whenever possible. Usually only three crossings are needed (one
main line) for a four-leg intersection, and only two roadway crossings are needed for a T
intersection. In most cases, the conduit should cross both the main line and side street from the
corner where the controller is located.

Directional boring should normally be used when crossing the state route (main line). Open cut
trenching may only be used to install conduits under the following circumstances:
1. Existing roadways where the roadway is being resurfaced.
2. Existing roadways where substantial obstacles under the roadway will be encountered.
3. Where there is insufficient room for jacking or boring pits at the edges of the roadway.

Open cut trenching is not permitted across limited access roadways unless the entire pavement
surface is being replaced. Sign or signal bridges may not be used for roadway crossings.

1330.04(9)(c) Junction Boxes

Provide junction boxes at the following locations:

 Adjacent to the signal cabinet. A pull box or larger vault may be used in place of
multiple junction boxes.
 Adjacent to each signal pole. One box may serve multiple poles. The distance from a
pole to the first junction box should not exceed 10 feet without concurrence from
maintenance staff. Pole bases may not be used as junction boxes.
 Adjacent to each set of detector loops. These boxes contain the detector loop splices.
One box may serve multiple lanes, but the box should be no more than 50 feet from
the detector loop.
 At the end of each road crossing.
 In the middle of conduit runs where the number of bends would equal or exceed 360°.

Where possible, locate junction boxes out of paved areas and adjacent to (but not in) sidewalks.
New junction boxes may not to be placed in the pedestrian curb ramp or ramp landing of a
sidewalk. If a new junction box must be placed within sidewalk, locate it at the edge of the
sidewalk and designate it to be slip-resistant. Existing junction boxes located within new or
existing sidewalk, including ramps or landings, must be revised as follows:
 Existing junction boxes containing power conductors for the traffic signal (not including
street lighting), or wiring for the signal displays, may remain in place, even if they will
be within a sidewalk ramp or ramp landing.
 Existing junction boxes containing detector wiring may remain in sidewalks, but must
be relocated outside of sidewalk ramps and ramp landings. Designate that the
relocation work, including conduit adjustments and rewiring, be completed within a
single shift or provide temporary detection using another conduit path.
 All junction boxes which will be within sidewalk, sidewalk ramps, or ramp landings,
must be slip-resistant junction boxes. This includes replacing existing junction boxes
with slip-resistant junction boxes.

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 Under no circumstances may a junction box be located in a grade break for a sidewalk
ramp. Either the ramp must be redesigned or additional accommodations made in
construction to allow for the box to be relocated.

The fundamental principle is that if relocating a junction box requires shutting down a traffic
signal system, the junction box may remain in its existing location but must be replaced with a
slip-resistant junction box. See Chapter 1510 for additional ADA requirements.

Do not place junction boxes within the traveled way unless absolutely necessary. Make every
effort to locate new junction boxes and to relocate existing junction boxes outside the travel
lane or paved shoulder. If there is no way to avoid locating the junction box in the traveled way
or paved shoulder, heavy-duty junction boxes must be used. Avoid placing junction boxes in
areas of poor drainage. Do not place junction boxes within 2 feet of ditch bottoms or drainage
areas, or within vegetative filter strips or similar water treatment features which may be
present. The maximum conduit capacities for various types of junction boxes are shown in the
Standard Plans.

1330.05 Preliminary Signal Plan

All traffic signal work which installs or modifies detection or display equipment, with the sole
exception of projects where induction loops are being removed and replaced in the same
location, requires a preliminary signal plan for the Project File. The type of preliminary signal
plan depends on the type of work being performed. For a new traffic signal system or complete
system replacement, a Full Preliminary Signal Plan is required. For all other work, a Basic
Preliminary Signal Plan is required. Include a brief discussion of the issue that is being addressed
by the project. Provide sufficient level of detail on the preliminary signal plan to describe all
aspects of the signal installation, including proposed channelization modifications. The plan
scale should not be smaller than “1 inch = 30 feet” (“1 inch = 20 feet” is preferable) – plans may
be reduced to “1 inch = 40 feet” with prior approval.

Submit a copy of the preliminary signal plan to the State Traffic Engineer for review and
comment. A preliminary signal plan must be submitted to the State Traffic Engineer regardless
of the originator of the design. Allow two to three weeks for review of the preliminary signal
plan. After addressing all review comments, finalize the plan and preserve as required by
1330.07 Documentation. Prepare the contract plans in accordance with the Plans Preparation
Manual.

If HQ Traffic is preparing the contract Plans, Specifications, and Estimate (PS&E) package for the
signal system portion of the project, submit the following items with the preliminary signal plan:
1. Contact person.
2. Charge numbers.
3. Critical project schedule dates.
4. Existing and proposed utilities, both underground and overhead.
5. Existing intersection layout, if different from the proposed intersection.
6. (Turning movement traffic counts (peak hour for isolated intersections) and a.m., midday,
and p.m. peak-hour counts if there is another intersection within 500 feet.
7. Electrical service location, source of power, and utility company connection requirements.

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After the PS&E package for the signal system portion of the project is prepared, the entire
package is transmitted to the region for incorporation into its contract documents.

1330.05(1) Basic Preliminary Signal Plan

The Basic Preliminary Signal Plan includes the following elements, at a minimum:
a. All pavement markings.
b. Sidewalks, curb ramp, and level landing areas.
c. All pole types and locations.
d. All vehicle and pedestrian display types and locations.
e. All vehicle (car and/or bicycle) detector types and locations. Include detection zones for
non-loop detectors.
f. All pedestrian pushbutton types and locations.
g. All emergency vehicle preemption (EVP) detector locations.
h. Phase diagram, including pedestrian movements and EVP channel assignments.

1330.05(2) Full Preliminary Signal Plan

The Full Preliminary Signal Plan includes all elements required for the Basic Preliminary Signal
Plan, with the following additional items (list is continued from above):

a. Cabinet locations with door orientations.

b. Traffic barrier (guardrail, concrete barrier, etc.) locations.

c. Drainage items.

d. Left-turn radii, including beginning and ending points.

e. Corner radii, including beginning and ending points.

f. Railroad preemption requirements.

g. Illumination treatment, including a calculation summary showing the average light level,
average/minimum uniformity ratio, and maximum veiling luminance ratio. (See Chapter
1040 for more information on illumination design requirements.)

h. Traffic counts, including left-turn movements.

i. Speed study information indicating 90th, 85th, and 10th percentile speeds for all
approaches. For any new approach, or any approach where the existing speed will
change, the design posted speed may be provided instead.

j. Utilities information, for any potential overhead or underground utility conflicts.

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1330.06 Operational Considerations for Design

This section describes operational guidance for traffic signals. These operational requirements
will directly affect the design of the traffic signal, particularly in regards to signal display types
and locations.

All traffic signals should be periodically re-evaluated, to determine if timing or phasing changes
would result in more efficient operation of the traffic signal, or in the case of interconnected
systems, the corridor or network. Changes in traffic volumes, posted speeds, or other factors
may influence turning movement phasing operations (protected, protected/permissive, or
permissive), green times, yellow change intervals, and other operational parameters.

1330.06(1) Left-Turn Phasing

Left-turn phasing can either be permissive, protected/permissive, or protected. It is not
necessary that the left-turn mode for an approach be the same throughout the day. Varying the
left-turn mode on an approach among the permissive only, protected/permissive, and
protected-only left-turn modes during different periods of the day is acceptable. Examples are
included in the phase diagrams shown in Exhibit 1330-20 and Exhibit 1330-21.

For permissive left turns, the permissive left turn phase shall not terminate separately from
the conflicting phase(s) (typically, the opposing through phase). This is to prevent placing
left turning traffic in a yellow trap.
1. Permissive Left-Turn Phasing

Permissive left-turn phasing requires the left-turning vehicle to yield to opposing through
traffic and pedestrians. Permissive left-turn phasing is used when the following are true:

a. Turning volume is minor.

b. Adequate gaps occur in the opposing through movement.

c. Adequate sight distance beyond the intersection is provided.

This phasing is more effective on minor streets where providing separate protected turn
phasing might cause significant delays to the higher traffic volume on the main street. On
single-lane approaches with a posted speed of 45 mph or above, or where sight distance
approaching the intersection is limited, channelization should include a separate left-turn
storage lane for the permissive movement to reduce the potential for rear-end-type
collisions and delay to through movements.

Unless there is a dedicated left-turn lane, do not provide a separate display for permissive
left turns. When there is a dedicated left-turn lane, a three-section flashing yellow arrow
display (with steady red arrow, steady yellow arrow, and flashing yellow arrow displays)
should be used for the left-turn lane, as this provides a more positive indication of the
permissive turning movement.
2. Protected/Permissive Left-Turn Phasing

Protected/permissive left-turn phasing provides both a protected phase and a permissive

phase for the same lane, using the same signal display. Where left-turn phasing will be
installed and conditions do not warrant protected-only operation, consider
protected/permissive left-turn phasing. Protected/permissive left-turn phasing can result in

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increased efficiency at some types of intersections, particularly “T” intersections, ramp

terminal intersections, and intersections of a two-way street with a one-way street where
there are no opposing left-turn movements.

Protected/permissive left-turn phasing is NOT allowed under the following conditions:

a. For new signals, on an approach where Warrant 7 is met and there are five or more left-
turning collisions on that approach included in the warranting collisions. This condition
requires protected left turn phasing.

b. For existing signals, when documentation shows that existing protected left-turn phasing
was installed due to left-turn collisions.

c. When sight distance for left-turning vehicles, as outlined in AASHTO’s A Policy on the
Geometric Design of Highways and City Streets, cannot be met.

d. On intersection approaches where the opposing approach has three or more lanes
(including right-turn lanes) and either the posted speed limit or 85th percentile speeds
for the opposing approach are at or above 45 mph.

e. On intersection approaches that have dual left-turn lanes, including approaches with left
only and through-left lanes.

Where there is a separate left-turn lane, protective/permissive displays may use either of
the following display arrangements:
 A dedicated four-section arrow display, with steady red arrow, steady yellow arrow,
flashing yellow arrow, and steady green arrow displays (four-section FYA). A three-
section display with a bi-modal flashing yellow arrow / steady green arrow may only
be used if the signal support cannot accommodate a four-section signal display.
 A shared five-section cluster (doghouse) display, placed over the wide line between
the left turn lane and the adjacent through lane.

Where there is no separate left-turn lane, only a five-section vertical (recommended) or

cluster display may be used. The five-section display is used in place of the left of the two
required through displays for that approach.

Protected/permissive displays may run as lead or lag. The display cycle will depend on the
display type and whether the protected left leads or lags:
 Leading 4-section FYA: steady green arrow, steady yellow arrow, steady red arrow,
flashing yellow arrow, steady yellow arrow, steady red arrow.
 Leading 5-section: green arrow, yellow arrow, red ball, green ball, yellow ball, red
ball. Option: green ball may come up with green arrow, but the arrow and ball
displays should cycle to yellow and red together (similar to lagging 5-section)
 Lagging 4-section FYA: flashing yellow arrow, steady green arrow, steady yellow
arrow, steady red arrow
 Lagging 5-section: green ball, green ball with green arrow, yellow ball with yellow
arrow, red.

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3. Protected Left-Turn Phasing

Protected left-turn phasing provides the left-turning vehicle a separate phase, and
conflicting movements are required to stop.

Use protected left-turn phasing under the following conditions:

a. Multi-lane left turn movements, including left and through-left from the same approach.

b. The left-turn is onto a roadway with a rail crossing.

c. Where Warrant 7 is met and there are five or more left-turning collisions on that
approach included in the warranting collisions. Protected left-turn phasing is
recommended even when there are as few as three left-turning collisions on that
approach. This includes left-turning collisions involving pedestrians.

d. Where the peak-hour turning volume exceeds the storage capacity of the left-turn lane
and one or more of the following conditions is present:

i. The posted speed or the 85th percentile speed of the opposing traffic is 45 mph or
higher.

ii. The sight distance to oncoming traffic is less than 250 feet when the posted or 85th
percentile speed is 35 mph or below, or less than 400 feet when the posted or 85th
percentile speed is above 35 mph.

iii. The left-turn movement crosses three or more lanes (including right-turn lanes) of
opposing traffic.

iv. Geometry or channelization is confusing, such as skewed intersections, offset-T

intersections, or intersections which require unusual maneuvers to traverse.

There are three typical operational arrangements for protected left turns:
 Leading Lefts: The left turns are served before the associated through movements.
This is the most common operational arrangement. Example: Phases 1 and 5 (major
street lefts) are served first, then phases 2 and 6 (major street throughs) are served.
 Lagging Lefts: The left turns are served after the associated through movements.
Example: Phases 4 and 8 (minor street throughs) are served first, then phases 3 and
7 (minor street lefts) are served.
 Offset (or Lead/Lag) Lefts: One left turn is served before the associated through
movements, and the opposing left turn is served after the associated through
movements. Example: Phase 1 (one major left turn) is served first (phase 6 may be
served at the same time), then phases 2 and 6 (major throughs) are served, and
then phase 5 (opposing major left turn) is served (phase 2 may still be served with
phase 5).

Check that all turning movements provide turning clearance for opposing turn phases. If the
opposing left-turning vehicle paths do not have 4-foot minimum—12-foot desirable—separation
between them, split or offset (lead/lag) phasing will have to be used.

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1330.06(2) Right-Turn Phasing

Right turns typically do not operate with their own phasing unless there is a dedicated right turn
lane. When there is no dedicated right turn lane, right turns are normally a permissive
movement from the right most through lane, depending on pedestrian phases in use. When
there is a dedicated right turn lane, right-turn phasing effectively operates the same as left-turn
phasing.

Dedicated right turn lanes may be operated the same as left turn lanes: permissive,
protected/permissive, or protected. However, right turn phase operation needs to take into
account any pedestrian crossing on the receiving side of the right turn. If there is a conflicting
pedestrian phase – typically a pedestrian phase running concurrent with the through phase from
which the right turn is being made – the right turn phase may only be operated as permissive.

Dedicated right turn lanes operated as permissive and protected/permissive are recommended
to have their own displays, but may use a shared display with the adjacent through lane.
Dedicated right turn lanes operated as protected must use their own display. Right turn displays
are arranged and operated the same as those listed for left turns in 1330.06(1). As with left
turns, a permissive right turn phase shall not terminate separately from the conflicting phase(s)
(typically, the opposing through phase).

Separate right turn phasing also needs to consider some additional operational modes and
issues:

1. Right-Turn Overlapped Phasing

A right turn overlap is when a protected right turn is allowed at the same time as a
complementary protected left turn, and is recommended when the lane and phase
configuration will support this operation. When this operation is used, the left turn must be
signed that U-turns are prohibited.

When right turn overlaps are used, the wiring of the right turn displays will depend on the
operating mode of each display section:
 Permissive: Connect permissive display sections to the same terminals as the
associated through phase.
 Protected: Protected display sections may either be:

(a) Connected to the complementary left turn phase. Use this arrangement when the
protected right turn will only be run concurrent with the complementary left turn
phase.

(b) Connected to an overlap phase. Use this arrangement when the protected right turn
will be run with both the complementary left turn phase and with the through phase
associated with the right turn.

2. Multiple-Lane Right-Turn Phasing

Multiple-lane right turns may be run independent or overlapped as described above. Multiple-
lane right turns can cause operational challenges when “right turn on red” is permitted at the
intersection. Verify that there is adequate sight distance and adequate receiving lanes are
available to minimize the possibility of collisions. In most cases, a single unrestricted “right-turn-

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only” lane approach with a separate receiving lane (auxiliary lane) will have a similar capacity as
the two lane right-turn phasing.

1330.06(3) Typical Signal Phasing Arrangements

The following diagrams show typical phasing diagrams for four-way and three-way intersections.

Exhibit 1330-20 Phase Diagrams: Four-Way Intersections

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Exhibit 1330-21 Phase Diagrams: Three-Way Intersections

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1330.06(4) Phasing at Railroad Crossings

Traffic signals near railroad crossings have additional special phasing arrangements. To provide
for efficient signal operations during a rail crossing, ensure that there are dedicated turn lanes
for movements turning onto the tracks. These turn lanes should be on their own dedicated
phases, so that they may be omitted from the signal timing (held in red) during the rail crossing.
This allows for as many of the other intersection movements as possible to continue to operate
– a timing scheme referred to as “Limited Service Operation” (LSO).

Just prior to LSO, when railroad preemption is used, the traffic signal will shift to a “Track
Clearance Green” (TCG) phase. TCG shifts non-conflicting phases to green to allow vehicles to
clear the railroad tracks. Examples of a TCG phase and LSO are shown in Exhibit 1330-22.
Standalone queue cutter signals do not have a TCG phase – contact the HQ Traffic Office for
operational guidance on standalone queue cutter signals.

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Exhibit 1330-22 Phasing at Railroad Crossings

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1330.06(5) Accessible Pedestrian Signals (APS)

APS are required to be operated as follows:
1. All APS at an intersection must use either rapid tick or speech messages – mixed operations
at a single intersection are not allowed.
2. Street names in speech messages shall be limited to the basic street name. Do not include
cardinals (N, S, E, etc.) or street type (street, avenue, road, etc.) unless needed to avoid
confusion where two streets have the same name, such as 2nd Avenue and 2nd Street or
Center Drive at Center Way.
3. Walk messages shall be in the format “Walk sign is on to cross <street>”.
4. Button press messages during flashing or solid DON’T WALK phases shall be in the following
formats:
a. Short press: “Wait”.
b. Long press: “Wait to cross <street1> at <street2>”. Street names shall use the same
format described above.
c. Long press with extended crossing time: “Wait to cross <street1> at <street2> with
extended crossing time”.
5. Audible countdowns shall not be used. The APS shall default to the locator tone during any
phase other than WALK.

1330.07 Documentation
The following original signal design documents shall be included in a Signal System file and
provided to the region Traffic Office or owning agency:
1. Signal Permit, including Signal Warrant Analysis and supporting documentation.
2. FHWA Approval for Experimentation.
3. Signal Standard Design Chart, including signal support engineering calculations.
4. Signal Detection Zone Placement. Include calculations if used.
5. Signal Wiring Diagram and Conduit Fill calculations.
6. Railroad preemption calculation and interconnect setup.
7. Any third party documentation provided.
8. Approved Preliminary Signal Plan.
9. Emergency Preemption Equipment selected.
10. Transit Priority Preemption and associated agreements.

Copies of items 1 and 2 are also required to be included in the DDP. Copies of items 3 through
10 are also required to be included in the Project File (PF).

Refer to Chapter 300 for additional design documentation requirements.

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1330.08 References
The following references are used in the planning, design, construction, and operation of traffic
control signals installed on state highways. The RCWs noted are specific state laws concerning
traffic control signals, and conformance to these statutes is required.

1330.08(1) Federal/State Laws and Codes

Americans with Disabilities Act of 1990 (ADA) (28 CFR Part 35)

Revised Code of Washington (RCW) 35.77, Streets – Planning, establishment, construction, and
maintenance

RCW 46.04.450, Railroad sign or signal

RCW 46.04.600, Traffic control signal

RCW 46.04.62250, Signal preemption device

RCW 46.61.050, Obedience to and required traffic control devices

RCW 46.61.055, Traffic control signal legend

RCW 46.61.060, Pedestrian control signals

RCW 46.61.065, Flashing signals

RCW 46.61.070, Lane-direction-control signals

RCW 46.61.072, Special traffic control signals – Legend

RCW 46.61.075, Display of unauthorized signs, signals, or markings

RCW 46.61.080, Interference with official traffic-control devices or railroad signs or signals

RCW 46.61.085, Traffic control signals or devices upon city streets forming part of state
highways – Approval by department of transportation

RCW 46.61.340, Approaching train signal

RCW 47.24.020(6) and (13), Jurisdiction, control

RCW 47.36.020, Traffic control signals

RCW 47.36.025, Vehicle-activated traffic control signals – Detection of motorcycles and bicycles

RCW 47.36.060, Traffic devices on county roads and city streets

Washington Administrative Code (WAC) 468 18-040, Design standards for rearranged county
roads, frontage roads, access roads, intersections, ramps and crossings

WAC 468-18-050, Policy on the construction, improvement and maintenance of intersections of

state highways and city streets

“City Streets as Part of State Highways: Guidelines Reached by the Washington State
Department of Transportation and the Association of Washington Cities on the Interpretation of

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Selected Topics of RCW 47.24 and Figures of WAC 468-18-050 for the Construction, Operations
and Maintenance Responsibilities of WSDOT and Cities for Such Streets,” April 30, 1997.

WAC 468-95, Manual on Uniform Traffic Control Devices for Streets and Highways (Washington
State Supplement)

1330.08(2) Design Guidance

A Policy on the Geometric Design of Highways and City Streets (Green Book), AASHTO
Guide for Determining Time Requirements for Traffic Signal Preemption at Highway-Rail Grade
Crossings (TxDOT Form 2304) and Instructions for Form 2304 (TxDOT Form 2304-I), Texas
Department of Transportation
 http://www.txdot.gov/inside-txdot/forms-publications/forms/rail.html
Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)
Plans Preparation Manual, M 22-31, WSDOT
Revised Draft Guidelines for Accessible Public Rights-of-Way, (PROWAG), November 23, 2005,
United States Access Board
Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21 01, WSDOT
Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications),
M 41-10, WSDOT
WSDOT Traffic Design Resources
 www.wsdot.wa.gov/design/traffic/

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1340.01 General
1340.02 Access Control
1340.03 Driveway Design
1340.04 Documentation
1340.05 References

1340.01 General
For the purpose of this chapter, and to remain consistent with WSDOT’s Standard Plans and
AASHTO terminology, the terms “access” and “approach” will be referred to as “driveway.” An
access on a managed access highway is defined as an “access connection,” while an access on a
limited access highway is defined as an “approach.”

Driveways are as much about access as they are about driveway design. This chapter describes
the pertinent access criteria along with the design guidelines, including two design templates
based on design vehicle, sidewalks, and sight distance criteria, for driveway connections on the
state highway system. WSDOT controls driveways on all limited access state highways, and
regulates driveways on all managed access state highways outside the incorporated limits of a
city or town. RCW 47.50.030 states that cities and towns, regardless of population size, are the
permitting authority for managed access state highways within their respective incorporated
city and town limits. The RCW also requires those cities and towns to adopt standards for access
permitting on managed access state highways that meet or exceed WSDOT standards, provided
those adopted standards are consistent with WSDOT standards.

1340.02 Access Control

Limited access highways are roadways to which WSDOT has acquired the access rights from
abutting property owners. Driveways, if they have been allowed, are documented and recorded

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in the deed and right-of-way limited access plan. Chapter 530 describes the three levels of
limited access highways: full, partial, and modified. Any change to the number, type, and use of
a limited access driveway must be approved by Headquarters through the process outlined in
Chapter 530 and Chapter 550. A general permit is required to allow any new construction or
repairs for a deeded road approach on a limited access highway. Access connection permits are
not issued on limited access highways.

Any state highway that is not a limited access highway is a managed access highway. Chapter
540 describes the five classes of managed access highways: Class 1 (most restrictive) to Class 5
(least restrictive). In addition to the five access control classes, there are also corner clearance
criteria that must be used for access connections near intersections (see Section 540.04 and
Exhibit 540-2). An access connection permit is required to allow the use, operation, and
maintenance of a driveway connection on a managed access highway, outside incorporated
cities, where WSDOT is the access permitting authority. Check with Development Services
to ascertain where WSDOT has permitting authority (such as tribal lands or National Parks).

When evaluating access connections or approaches on a project, review existing driveways for
possible alterations, relocations, consolidations, or closures. The first step in that process is to
determine the legality of each driveway. The region Development Services Office can provide a
list of the permitted driveway connections on a managed access highway, noting that, per RCW
47.50.080, Permit removal, “Unpermitted connections to the state highway system in existence
on July 1, 1990, shall not require the issuance of a permit and may continue to provide access to
the state highway system, unless the permitting authority determines that such a connection
does not meet minimum acceptable standards of highway safety.” As a result, driveway
connections on a managed access state highway can be considered to be permitted,
grandfathered, or unpermitted as described below:
• Permitted driveways hold a valid permit and shall remain valid until modified or revoked.
• Grandfathered driveways that were in existence and in active use consistent with the type
of connection on July 1, 1990, may continue to provide connection to the state highway
system. The term “Grandfathered” driveway, or connection, is not a term defined in statute
or rule. It is a commonly used term to define legal connections to managed access state
highways, in place prior to July 1, 1990. They do not require the issuance of a new permit
and may continue to provide access to the state highway system, unless the permitting
authority determines that such a connection does not meet minimum acceptable standards
of highway safety.
• Unpermitted driveways are not allowed. The permitting authority may initiate action to
close the unpermitted driveway in compliance with the applicable chapters of 47.50 RCW
and 468-51 and 468-52 WAC. These are driveways that do not have a permit and were
constructed after July 1, 1990.

If a WSDOT project proposes to alter, relocate, consolidate, or close a driveway—regardless

of whether the driveway is permitted, grandfathered, or unpermitted—it is required that a new
access connection permit be issued for any driveways that are to remain. If a driveway is to
be removed, formal notification to the property owner will be provided as specified in WAC
468-51-040. Unless determined otherwise, the affected property owners of driveways that will
be altered, relocated, consolidated, or closed will not have the right of an Adjudicative Hearing.

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Additional information regarding this process can be obtained by contacting your region’s
Development Services Office.

On limited access highways, both the region Development Services and Real Estate Services
offices may provide assistance to determine the legality of an existing driveway. Federal
Highway Administration approval is required for driveway modifications on Interstate facilities.

1340.03 Driveway Design

The design of a driveway is based on the usage, design vehicle, and traffic volumes anticipated
for the driveway. Generally, the driveway should be designed to accommodate the largest
vehicle that will regularly use the driveway. For example, a residential driveway connection will
typically have smaller radii and a narrower access width than a higher-volume commercial
driveway.

However, if the property owner regularly has larger-wheelbase vehicles using the driveway, such
as a home-based work vehicle, recreational vehicle, or truck and boat trailer combination, then
a larger driveway may be appropriate.

Conversely, some driveways, such as a rural locked and gated utility, farm, or logging access that
larger vehicles sometimes use, may be better served with a smaller and narrower access. This is
based on infrequent use and to prevent unauthorized use or dumping of debris on or near the
driveway. Other design considerations are:
• Prevent stormwater from flowing onto the roadway from the driveway.
• Properly size culverts under the driveway to adequately accommodate the conveyance of
stormwater in the roadway ditches and swales.
• Provide driveway sight distance.
• Accommodate for mailbox placement.
• Ensure surfacing materials and depths are appropriate.
• Generally, extend paving to the right of way line depending on the location/purpose of the
driveway. The desirable intersection angle of the driveway is 90°, with 60° to 120° allowed.
• Where driveways intersect sidewalks, bike lanes, shared-use paths, or trails especially near
schools, consider narrowing the driveway and/or reducing the radii to the minimum
required to accommodate the design vehicle. Narrower driveway width and/or smaller
driveway radii can reduce exposure and speed differentials between vehicles entering /
exiting the driveway and pedestrians or bicycles.

1340.03(1) Design Templates

There are two driveway design templates for use where there is no adjacent sidewalk. When a
driveway connection has or will have adjacent sidewalk, see Section 1340.04. In both template
designs, the sideslopes of the driveway shall not be steeper than 6H:1V. These templates may
be used on both limited access and managed access state highways. If an Interstate limited
access driveway is allowed, it must be gated. Use the design template dimensions that will
accommodate the intended use of the driveway and will not adversely affect the operations of
the traveled way of the state highway. See Chapter 530 and Chapter 550 for documentation

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requirements for access approaches to limited access facilities. Design driveways with as small a
foot print as possible while accommodating the design vehicle specific to that driveway. Use
turn simulation software (such as AutoTURN®) to verify the driveway design will accommodate
the largest vehicle that will regularly use the driveway. Considering the context of use, Exhibit
1340-1 is generally used for private, special use, and low volume commercial driveways with
design vehicles of SU-30, BUS, and smaller. Exhibit 1340-2 is generally used for low volume
commercial and special use driveways with design vehicles of SU-30, BUS, and larger.

Driveways to developments with greater than 1,500 (estimated) average daily trips both
entering and exiting the development (shopping malls, housing developments, commercial
complexes, etc.) should be designed as an intersection leg (see Chapter 1310).

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Exhibit 1340-1 Driveway Design Template SU-30 and Smaller

Notes:
[1] Culvert pipe with beveled end treatment (see Chapter 1600). See Hydraulics Manual, Road
Approach and Driveway Culverts for details.
[2] When the travel lanes are bituminous, a similar surface may be used on the approaches.
[3] For mailbox location and type, see Section 1340.07 and Chapter 1600.
[4] Not to exceed ±8% maximum algebraic difference from shoulder slope.
[5] Vertical alignment not to exceed a 3¼-inch hump or a 2-inch depression in a 10-foot chord

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Exhibit 1340-2 Driveway Design Template SU-30 and Larger

Notes:
[1] Culvert pipe with beveled end treatment (see Chapter 1600). See Hydraulics Manual,
“Private Road Approach and Driveway Culverts” for details.
[2] When the travel lanes are bituminous, a similar surface may be used on the approaches.
[3] For mailbox location and type, see Section 1340.07, Chapter 1600.
[4] Not to exceed ±8% maximum algebraic difference from shoulder slope.
[5] Vertical alignment not to exceed a 3¼-inch hump or a 2-inch depression in a 10-foot chord.
[6] Check turning template of driveway design vehicle

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1340.03(2) Sidewalks
Driveways adjacent to sidewalks shall be designed and constructed in accordance with this
chapter and Standard Plan F-80.10. Driveway width will be as stated on the access permit. The
sidewalk shall be designed and constructed in accordance with Chapter 1510 and Section F of
the Standard Plans.

1340.03(3) Sight Distance

A driver on the highway needs to see far enough ahead to understand, react, and take actions
appropriate for the conditions, such as a vehicle entering or leaving the highway at a driveway.
In addition, drivers entering the highway from a driveway need to see enough of the highway,
left and/or right, so they can enter the highway in a reasonably safe manner.

Design and locate driveways such that the sight distances, based on an eye height of 3.5 feet
and an object height of 3.5 feet, meet or exceed the distances shown in Exhibit 1340-3; these
distances may require an approaching vehicle to reduce speed or stop to prevent a collision. In
addition, provide decision sight distance for through traffic at all utility and special-use
driveways on facilities with limited access control (see Chapter 1260). The sight triangle areas
created by the sight lines should be clear of sight obstructions that might block or affect a
driver’s view of potentially conflicting vehicles. See Exhibit 1340-3.

Use intersection sight distance (see Section 1310.05) for road approaches with greater than
1,500 (estimated) average daily trips both entering and exiting the development at full build out.

Exhibit 1340-3 Driveway Sight Distance

Mainline Posted Speed (mph) 25 30 35 40 45 50 55 60 65 70

Driveway Sight Distance (ft)
155 200 250 305 360 425 495 570 645 730
Eye and object height 3.5 ft.

Notes:
[1] Measured from the edge of traveled way to the drive’s eye. If the desirable 18-foot setback cannot
be achieved, obtain as much as practicable, down to a 10-foot minimum.
[2] Not required for driveways that are restricted by raised channelization to be right in and right out
only.

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1340.03(4) Stormwater and Drainage

Slope driveways away from the highway to prevent stormwater and and other debris from
flowing onto the highway traveled lanes and shoulders. Use of curbs, catch basins, or other
measures may be needed to divert stormwater where it is not feasible to slope the driveway
away from the highway. Locate catch basins outside of the vehical paths of the driveway.

Install beveled end culverts sized in accordance with the Hydraulics Manual if the driveway
traverses an existing ditch or swale in the state highway right of way. Contact either the Region
Hydraulic Engineer or the applicable Region Maintenance Office for assistance. Consider placing
quarry spalls at each end of the open culvert to prevent erosion.

Profile the road approach as shown in Exhibits 1340-1 or 1340-2 while ensuring that roadway
runoff is not a problem. Locate culverts as far from the traveled way as possible. In Exhibits
1340-1 and 1340-2, roadway runoff can be a concern if the grade from the edge of shoulder to
the right of way line and the slope parallel to the mainline is a flat or minus grade. If needed, a
curb may be placed and if needed, a catch basin can also be placed as shown in Exhibit 1340-2.
When considering a curb, see Chapter 1239 as allowable curb locations, heights, and offset
distances can vary based on mainline speed. Construct road approaches and related areas such
that they do not impair drainage within the right of way or alter the stability of the roadway
subgrade.

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1340.03(5) Mailboxes
Refer to Chapter 1600, Roadside Safety, Mailboxes, for guidance regarding the placement of
mailboxes.

Standard Plans, Mailbox Support Types, H-70.10-01, H-70.20-01, and H-70.30-02

1340.04 Documentation
Refer to Chapter 300 for design documentation requirements.

1340.05 References

1340.05(1) State Laws and Codes

Revised Code of Washington (RCW) 47.32.150, Approach roads, other appurtenances – Permit

RCW 47.32.160, Approach roads, other appurtenances – Rules – Construction, maintenance of

approach roads

RCW 47.32.170, Approach roads, other appurtenances – Removal of installations from right-of-
way for default

Chapter 47.50 RCW, Highway access management

Chapter 47.52 RCW, Limited access facilities

Chapter 468-51 Washington Administrative Code (WAC), Highway access management

access permits – Administrative process

Chapter 468-52 WAC, Highway access management – Access control classification system
and standards

Chapter 468-58 WAC, Limited access highways

1340.05(2) Design Guidance

Right of Way Manual, M 26-01, WSDOT
Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT
Development Services Manual, M 3007, WSDOT
Limited Access and Managed Access Master Plan, WSDOT
 https://www.wsdot.wa.gov/design/accessandhearings/

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1350.01 General
1350.02 References
1350.03 Plans
1350.04 Traffic Control Systems
1350.05 Nearby Roadway Intersections
1350.06 Pullout Lanes
1350.07 Crossing Surfaces
1350.08 Crossing Closure
1350.09 Traffic Control During Construction and Maintenance
1350.10 Railroad Grade Crossing Petitions and WUTC Orders
1350.11 Grade Crossing Improvement Projects
1350.12 Light Rail
1350.13 Documentation

1350.01 General
Highway-rail grade crossings (“grade crossings”) are the intersection of two modes of
transportation with very different physical and operational characteristics. Because of the
inherent limitations associated with train operations, RCW 46.61.350 gives train traffic
the right of way at grade crossings, thereby assigning motorists the primary responsibility
to avoid collisions.

There are many variables that influence a motorist’s ability to react appropriately at
grade crossings, including what information is available to them as they approach the
crossing and human factors such as competing decisions, distractions, and impaired
driving. Primary factors to consider in the design of grade crossings are roadway and
railway geometry; available sight distance; highway and railway speeds; competing
decisions or visual distractions; and the types of warning devices at the grade crossing.
Another aspect of grade crossing design is coordination of highway traffic signal
operations with grade crossing active warning devices (“railroad preemption”) when
signalized intersections are located near grade crossings. In such instances, railroad
preemption is designed to clear the tracks of any vehicles that may be stopped as a
result of the highway traffic signal when a train is approaching the grade crossing.
Further guidance on railroad preemption requirements is provided in Chapter 1330.

Grade crossings are also unique due to their multijurisdictional nature. Highway
authorities and railroad companies are each legally responsible for different elements
at grade crossings. Additionally, the Washington Utilities and Transportation
Commission (WUTC) is the state regulatory agency with oversight of public grade
crossings in Washington, except within the limits of first class cities in accordance
with RCW 81.53.240. Establishing new crossings, altering existing crossings, or
closing crossings all require WUTC approval. Therefore, highway projects that
include a grade crossing will generally require close coordination with both the
railroad company and the WUTC.

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Projects that include grade crossings will generally require execution of construction and
maintenance agreements between the Washington State Department of Transportation
(WSDOT) and the railroad company. These agreements specify the design elements of
the crossing, work that the railroad will perform on behalf of the project, payment terms,
and legal provisions. It may also be necessary for WSDOT to obtain easements from the
railroad company for new grade crossings on railroad property. The Headquarters (HQ)
Railroad Liaison is responsible for facilitating highway project coordination with railroad
companies, including developing agreements and obtaining WUTC approvals. Obtaining
necessary approvals from the railroad company may take several months. Contact the HQ
Railroad Liaison early in the design phase so that all necessary design and agreement
coordination can be completed according to project schedules.

More information about general railroad coordination and WUTC requirements is

provided in Chapter 3 of the Utilities Manual.

1350.02 References
(1) Federal/State Laws and Codes
Revised Code of Washington (RCW) 81.53, Railroad crossings
 http://apps.leg.wa.gov/rcw/default.aspx?cite=81.53

Washington Administrative Code (WAC) 480-62-150, Grade crossing petitions

 http://apps.leg.wa.gov/wac/default.aspx?cite=480-62-150

(2) Design Guidance

Agreements Manual, M 22-99, WSDOT
 http://wwwi.wsdot.wa.gov/publications/manuals/m22-99.htm

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA;
as adopted and modified by Chapter 468-95 WAC “Manual on uniform traffic control
devices for streets and highways” (MUTCD)
 www.wsdot.wa.gov/publications/manuals/mutcd.htm

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans),
M 21-01, WSDOT
 www.wsdot.wa.gov/publications/manuals/m21-01.htm

(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO
Guidance On Traffic Control Devices At Highway-Rail Grade Crossings, Highway/Rail
Grade Crossing Technical Working Group (TWG), FHWA, November 2002
 http://safety.fhwa.dot.gov/xings/collision/ twgreport/

Railroad-Highway Grade Crossing Handbook, FHWA, August 2007

 http://safety.fhwa.dot.gov/xings/com_roaduser/07010/

Manual on Uniform Traffic Control Devices Part 8. Traffic Control for Railroad
and Light Rail Transit Grade Crossings
 http://mutcd.fhwa.dot.gov/htm/2009/part8/part8_toc.htm

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1350.03 Plans
(1) Proposed Improvements
Include plans for proposed improvements to existing crossings and any new crossings
in the Plans, Specifications, and Estimates (PS&E) package. In addition to basic roadway
dimensions, signs, and markings, indicate the angle of crossing; number of tracks;
location of signals and other railway facilities (such as electrical/communications lines
and control boxes); and the limits of property ownership by the railroad company at the
crossing location.
For any project proposing to alter the horizontal or vertical alignment at a grade crossing,
including grade separations, show the alignment and profile for both the railroad and the
roadway for a minimum of 500 feet on all legs of the crossing. Show all other important
features that might affect the safety, operation, and design of the crossing, such as nearby
crossroads, driveways/entrances, buildings, and highway structures on the plans.

(a) Sight Distance

Sight distance is a primary consideration at railroad grade crossings. A railroad grade

crossing is comparable to the intersection of two highways where a sight triangle is
kept clear of obstructions or it is protected by a traffic control device. The desirable
sight distance allows a driver to see an approaching train at a distance that allows the
vehicle to stop well in advance of the crossing if signals, or gates and signals, are not
present (see Exhibit 1350-1, Case 2). Sight distances of the order shown are desirable
at any railroad grade crossing not controlled by railroad flashing light signals or gates
(active warning devices). Attainment of optimal sight distances is often difficult and
impracticable due to topography and terrain. Even in flat, open terrain, the growth of
crops or other seasonal vegetation can create a permanent or seasonal sight distance
obstruction. Furthermore, the properties upon which obstructions might exist are
commonly owned by the railroad or others. Evaluate installation of active devices
at any location where adequate sight distances cannot be provided. Include
communication with the railroad and the WUTC in your evaluation.
The driver of a vehicle stopped at a crossing with signal lights but no gates needs
to be able to see far enough down the tracks from the stop bar to be able to cross the
tracks before a train, approaching at maximum allowable speed, reaches the crossing
(see Exhibit 1350-1, Case 1).

(b) Highway Grade and Crossing Angle

Construct highway grades so that low-clearance vehicles do not hang up on tracks

or damage them. (See Chapter 1220 for information on vertical alignment at railroad
grade crossings.) Whenever possible, design the roadway to cross grade crossings at
right angles. If bicycle traffic uses the crossing (this can be assumed for most roads),
provide a shoulder through the grade crossing at least as wide as the approach
shoulder width. If a skew is unavoidable, wider shoulders may be needed to permit
bicycles to maneuver to cross the tracks at right angles. (See Chapter 1520 for
information on bikeways crossing railroad tracks.) Consider installation of advance
warning signs indicating the presence of a skewed crossing for crossings where
engineering judgment suggests a benefit.

Include any engineering studies or sight distance measurements in the Design

Documentation Package (DDP).
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dt = Sight distance along railroad tracks (ft) Vv = Velocity of vehicle (mph)

dh = Sight distance along highway (ft) f = Coefficient of friction
de = Distance from driver to front of vehicle (8 ft) Vt = Velocity of train (mph)
D = Distance from stop line to nearest rail (15 ft) L = Length of vehicle (65 ft)
W = Distance between outer rails (single track W=5 ft)

Notes:
 Adjust for skewed crossings.
 Assume flat highway grades adjacent to and at crossings.

Case 2: Moving Vehicle

Case 1:
Train Departure Vehicle Speed (mph) Vv
Speed From Stop 10 20 30 40 50 60 70
(mph) Vt f=0.40 0.40 0.35 0.32 0.30 0.29 0.28
Distance Along Railroad From Crossing dt (ft)
10 240 146 106 99 100 105 111 118
20 480 293 212 198 200 209 222 236
30 721 439 318 297 300 314 333 355
40 961 585 424 396 401 419 444 473
50 1,201 732 530 494 501 524 555 591
60 1,441 878 636 593 601 628 666 706
70 1,681 1,024 742 692 701 733 777 828
80 1,921 1,171 848 791 801 833 888 946
90 2,162 1,317 954 890 901 943 999 1,064
Distance Along Highway From Crossing dh (ft)
69 135 220 324 447 589 751
Design sight distance for a combination of highway and train vehicle speeds and a 65-ft truck crossing a single
set of tracks at 90° (AASHTO).
Source: A Policy on Geometric Design of Highway and Streets, 2004, by the American Association of State Highway and
Transportation Officials.

Sight Distance at Railroad Crossing

Exhibit 1350-1

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1350.04 Traffic Control Systems

(1) Traffic Control System Elements
There are two categories of railroad warning devices: “passive” and “active.” Passive
devices include all signs and pavement markings. Active devices include flashing light
signals, railroad warning gates, and active advance warning systems, all of which are
activated by approaching trains.

(a) Passive Elements

1. The following signing elements are shown in the MUTCD, Part 8, Traffic
Control for Highway-Rail Grade Crossings:
• Highway-Rail Grade Crossing (Crossbuck) sign: Crossbuck signs
identify the location of the grade crossing and convey the same meaning as
a yield sign. The railroad is responsible for installation and maintenance of
Crossbuck signs.
Note: Railroads are required to upgrade standard Crossbuck signs at passive
grade crossings to “Crossbuck Assemblies” by December 31, 2019.
Crossbuck Assemblies are Crossbuck signs mounted in conjunction with
STOP or YIELD signs. Any projects that establish new passive crossings
or result in reconstruction of passive crossings should include design of
Crossbuck Assemblies. (See Chapter 8 of the MUTCD for additional
guidance.)
• Supplemental Number of Tracks (inverted “T”) sign: This sign is
mounted below the Crossbuck sign to indicate the number of tracks when
two or more tracks are involved. The railroad is responsible for installation
and maintenance of these signs.
• Grade Crossing Advance Warning sign (W10 sign series): The road
authority is responsible for installation and maintenance of these signs.
• Exempt sign: This is a supplemental sign that, when authorized by the
WUTC, may be mounted below the Crossbuck sign. When this sign is
approved, certain classes of vehicles, otherwise required to stop before
crossing the tracks, may proceed without stopping, provided no train is
approaching. The road authority is responsible for installation and
maintenance of these signs.
• Do Not Stop on Tracks sign: This sign is used where it is determined that
additional emphasis is needed to remind motorists of this legal requirement,
such as where nearby roadway intersections result in queuing back across the
tracks. The road authority is responsible for installation and maintenance of
these signs.
2. Pavement markings on all paved approaches are the responsibility of the road
authority and consist of RR Crossing markings in accordance with the Standard
Plans, No Passing markings, and Pullout Lanes, as appropriate.

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3. Consider the installation of illumination at and adjacent to railroad crossings

where an engineering study determines that better nighttime visibility of the
train and the grade crossing is needed. For example, where:
• A substantial number of railroad operations are conducted at night.
• Grade crossings are blocked for long periods at night by slow-speed trains.
• Collision history indicates that drivers experience difficulty seeing trains
during hours of darkness.

(b) Active Elements

1. Railroad Flashing Light Signals and Gates: These are active devices intended
to warn motorists of approaching trains and impose a stopping requirement. The
railroad is responsible for installation and maintenance of these devices.

2. Traffic Signal Interconnection (also known as “railroad preemption”): These

provide linkage between the railroad signals and adjacent traffic signals to allow
vehicles to clear the tracks at a traffic signal as a train approaches. They are
typically funded by the road authority and require cooperation with the railroad
for installation. The formation of a Railroad Crossing Evaluation Team is
required to determine signal railroad preemption requirements. (See Chapter
1330 for further guidance.)
3. Pre-Signals: These are traffic control signal faces that control roadway traffic
approaching a grade crossing in conjunction with the traffic control signal faces
that control traffic approaching a roadway-roadway intersection beyond the
tracks. Pre-signals are typically used where the clear storage distance is
insufficient to store one or more design vehicles.

4. Active Advance Warning Systems: These are supplemental flashing yellow

beacons mounted along with the grade crossing advance warning signs that are
interconnected to the railroad active warning devices. Activation of the railroad
active warning devices activates the beacons to provide motorists with an
advance indication that a train is approaching or occupying the crossing. Active
advance warning systems are typically used where roadway geometry prevents
a clear view of the grade crossing ahead, or where higher highway speeds may
require advance notification of an impending stopping requirement. Use a plaque
stating “Train When Flashing” as part of such systems.

5. Supplemental Safety Devices: Supplemental safety devices are typically used

at locations where it is known that motorists frequently drive around gates, where
unique local safety hazards exist, or as part of railroad quiet zones where trains
are no longer required to sound the locomotive horn. (For more information
about quiet zones, see  www.fra.dot.gov/us/content/1318.)
Typical supplemental safety devices include:
• Four-Quadrant Gate Systems: These are additional gates placed on the
opposite side of the roadway from the primary railroad warning gates that,
when lowered, make it impossible for motorists to drive around the lowered
gates. (See Chapter 8 of the MUTCD for additional information on four-
quadrant gate systems.

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• Median Separators: This is a system of raised delineators extending along the

roadway centerline back from the tip of a lowered railroad warning gate that
prevents motorists from being able to drive around the lowered gates. Make
median separators at least 60 feet in length where sufficient space is
available.

(c) Selection of Grade Crossing Warning Devices

At a minimum:
• All public grade crossings are required to be equipped with Crossbuck signs,
a supplemental plaque indicating the presence of multiple tracks (if applicable),
and advance warning signs.
• Railroad pavement markings are required at all crossings where active warning
devices are present or the posted legal speed limit is 40 mph or higher.
Passive warning devices notify drivers that they are approaching a grade crossing
and to be on the lookout for trains. In general, consider stand-alone passive warning
devices at grade crossings with low volumes and speeds on both the highway and
railway, and where adequate sight distances exist. Active warning devices are to be
considered at all other crossings. No national or state warrants have been developed
for installation of traffic control devices at grade crossings. Furthermore, due to the
large number of significant variables that need to be considered, there is no single
system of active traffic control devices universally applicable for grade crossings.
Warning systems at grade crossings should be based on an engineering and traffic
investigation, including input from the railroad and the WUTC. Primary factors to
consider in selecting warning devices are train and highway volumes and speeds;
highway and railway geometry; pedestrian volume; accident history; and available
sight distance.
Evaluate railroad signal supports and gate mechanisms as roadside features to be
considered for mitigation. Use traffic barrier or impact attenuators as appropriate
(see Division 16).

1350.05 Nearby Roadway Intersections

Operations at roadway intersections located near grade crossings can present significant
challenges for grade crossing safety. In particular, vehicle queues originating from the
roadway intersection and extending back to the grade crossing must be clear of the tracks
before the arrival of any trains. While RCW 46.61.570 prohibits motorists from stopping
on any railroad tracks, it is not uncommon for motorists to stop on tracks when focusing
on the downstream highway intersection rather than the immediate grade crossing.
For signalized highway intersections where vehicle queues result from a red signal
indication, clearance of vehicles from the grade crossing is accomplished through traffic
signal interconnection with the railroad warning signals (“railroad preemption”). When
railroad preemption is in place, an approaching train will initiate a special mode within
the highway traffic signal specifically designed to clear any vehicles from the tracks prior
to the arrival of the train at the grade crossing. Railroad preemption design involves a
specialized analysis that considers the distance between the roadway intersection and
grade crossing; queue clearance times; train speeds; the capabilities of the railroad active
warning devices; and other traffic signal phases.

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Where the distance between the grade crossing and the roadway intersection is not
sufficient to store a design vehicle, a pre-signal may be considered to prevent subsequent
vehicles from entering the grade crossing limits during the track clearance phases of the
downstream highway signal. Additionally, whenever a signalized roadway intersection
is located 500 feet from a grade crossing, a Railroad Crossing Evaluation Team, which
includes representatives from both WSDOT and the railroad company, will jointly
determine the need for and design of railroad preemption systems. (See Chapter 1330
for further guidance on railroad preemption requirements.)

Vehicle queues over the tracks can also result from operations at nonsignalized roadway
intersections; for example, where there is a short distance between the grade crossing and
a roadway intersection controlled by a STOP or YIELD sign. A “Do Not Stop on Tracks”
sign should be installed at locations where the distance between the grade crossing and
the roadway intersection is not sufficient to store a design vehicle or it is otherwise
determined that vehicle queues originating from the roadway intersection routinely
extend back to the grade crossing. To determine whether or not to consider a highway
traffic signal in such instances, refer to MUTCD Traffic Signal Warrant 9.

1350.06 Pullout Lanes

In accordance with RCW 46.61.350, certain vehicles are required to stop at all railroad
crossings unless the grade crossing is flagged or an “Exempt” sign is posted. Evaluate
the installation of “pullout” lanes when grade crossings have no active protection. Some
school districts have a policy that school buses must stop at all grade crossings regardless
of the type of control. Consider the installation of pullout lanes at any public grade
crossing used regularly by school buses or by trucks transporting flammable cargo or
explosives and at which they must stop.
Contact the local school district for school bus information. Contact the Truck Freight
Program and Policy Manager at the WSDOT HQ Freight Systems Division about truck
freight operations in the project vicinity.
Design pullout lane geometrics in accordance with Exhibit 1350-2. The minimum
shoulder width adjacent to the pullout lane is 3 feet.

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Chapter 1350 Railroad Grade Crossings

Ld = Total length of pullout lane, approach

La = Total length of pullout lane, exit

Approach Length Downstream Length

of Pullout Lane, Ld of Pullout Lane, La
Vehicle Speed Length Vehicle Speed Length
(mph) (ft) (mph) (ft)
30 235 30 *
40 320 40 360
50 435 50 720
60 530 60 1,200
*Taper length only

Typical Pullout Lane at Railroad Crossing

Exhibit 1350-2

1350.07 Crossing Surfaces

Railroads are responsible for the maintenance of crossing surfaces up to 12 inches outside
the edge of rail (WAC 480-62-225). Crossing surfaces can be constructed of a number of
different materials, including asphalt, concrete, steel, timber, rubber, or plastic. The most
common surface types used on state highway crossings are asphalt, precast concrete, and
rubber. Timbered crossings are frequently used for low-volume roads and temporary
construction crossings.
The life of a crossing surface depends on the volume and weight of highway and rail
traffic using it. Highway traffic not only dictates the type of crossing surface, but it also
has a major influence on the life of the crossing. Rough crossing surfaces impact the
motoring public far more than the railroad. Therefore, when a highway project passes
through a railroad grade crossing, consider the condition of the crossing surface. While
the existing condition might not warrant railroad investment in replacing it, the surface
might have deteriorated sufficiently to increase vehicle operating costs and motorist
inconvenience. In such cases, it may be effective to partner with the railroad to replace
the crossing as part of the highway project. Such partnerships typically consist of the
state reimbursing the railroad for all or a portion of the cost of the work.

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1350.08 Crossing Closure

The MUTCD states, “Any highway-rail grade crossing that cannot be justified should be
eliminated.” Coordination with the appropriate railroad and the Washington Utilities and
Transportation Commission is required before any grade crossing can be closed. If a state
route grade crossing appears unused, consult the HQ Railroad Liaison before taking any
action. Close at-grade crossings that are replaced by grade separations.

1350.09 Traffic Control During Construction and Maintenance

Provide work zone traffic control for projects at highway-rail grade crossings, which
need protection from train traffic. When highway construction or maintenance activities
affect a railroad crossing, the railroad company must be notified at least ten days before
performing the work (WAC 480-62-305(4)). Furthermore, whenever highway
construction or maintenance crews or equipment are working within 25 feet of an active
rail line or grade crossing, consult the railroad to determine whether a railroad flagger
is required. Current contact numbers for railroads may be obtained by contacting your
region Utilities Engineer or the HQ Railroad Liaison. Railroad flaggers differ from
highway flaggers in that they have information on train schedules and can generally
communicate with trains by radio. When flaggers are required, the railroad generally
sends the road authority a bill for the cost of providing this service.
Do not allow work zone traffic to stop or queue up on a nearby rail-highway grade
crossing unless railroad flaggers are present. Without proper protection, vehicles might
be trapped on the tracks when a train approaches. (See the MUTCD for more detailed
guidance.)
For projects requiring temporary access across a set of railroad tracks, contact the HQ
Railroad Liaison early in the design process since a railroad agreement or permit will
likely be required.

1350.10 Railroad Grade Crossing Petitions and WUTC Orders

The Washington Utilities and Transportation Commission (WUTC) is authorized by
statute (Title 81 RCW) to have regulatory authority over railroad crossings. Establishing
new crossings, closing existing crossings, or modifying existing grade crossings must be
approved by the WUTC (WAC 480-62-150). WUTC authority does not apply within the
limits of first class cities, in accordance with RCW 81.53.240. This is accomplished by
submitting a formal petition to the WUTC for a formal order. The HQ Railroad Liaison
will assist in the preparation and submittal of this petition. Include a copy of the petition
and WUTC findings and order in the Design Documentation Package.

1350.11 Grade Crossing Improvement Projects

The HQ Highways and Local Programs Office (H&LP) administers the federal (Section
130) Grade Crossing Safety Improvement Program. Project proposals are submitted by
local agencies, railroads, and WSDOT.

Contact H&LP or the HQ Railroad Liaison in the Utilities, Railroads, and Agreements
Section for more information.

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1350.12 Light Rail

Light rail transit systems have been implemented and will continue to be developed in
some urban areas of the state. For the most part, criteria for light rail transit crossings are
very similar to those for freight and passenger rail with the exception of locations where
light rail shares a street right of way with motor vehicles. The MUTCD now includes
guidance devoted exclusively to light rail transit and can be consulted as the situation
warrants.

1350.13 Documentation
For the list of documents required to be preserved in the Design Documentation Package
and the Project File, see the Design Documentation Checklist:
 www.wsdot.wa.gov/design/projectdev/

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Chapter 1360 Interchanges
1360.01 General
1360.02 Interchange Design
1360.03 Ramps
1360.04 Interchange Connections
1360.05 Ramp Terminal Intersections at Crossroads
1360.06 Interchanges on Two-Lane Highways
1360.07 Interchange Plans for Approval
1360.08 Documentation
1360.09 References

1360.01 General
The primary purpose of an interchange is to reduce conflicts caused by vehicle crossings and
minimize conflicting left-turn movements. Provide interchanges on all Interstate highways and
freeways, and at other locations where traffic cannot be controlled efficiently by intersections at
grade.

For additional information, see the following chapters:

Chapter Subject
520 Access control
530 Limited access
550 Access Revision Report
1103 Design controls
1106 Design element dimensions
1240 Turning widths
1250 Cross Slope and Superelevation
1310 Intersections
1410 HOV lanes
1420 HOV direct access connections

1360.02 Interchange Design

1360.02(1) General
All freeway exits and entrances, except HOV direct access connections, are to connect on the
right of through traffic. Variations from this will be considered only for special conditions.

HOV direct access connections may be constructed on the left of through traffic when they are
designed in accordance with Chapter 1420.

Provide complete ramp facilities for all directions of travel wherever possible. However, give
primary consideration to the basic traffic movement function that the interchange is to fulfill.

Complications are rarely encountered in the design and location of rural interchanges that
simply provide a means of exchanging traffic between a limited access freeway and a local

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Interchanges Chapter 1360

crossroad. Carefully consider the economic and operational effects of locating traffic
interchanges along a freeway through a community, particularly with respect to local access, to
provide convenient local service without reducing the capacity of the major route(s).

Where freeway-to-freeway interchanges are involved, do not provide ramps for local access
unless they can be added conveniently and without detriment to efficient traffic flow or
reduction of capacity, either ramp or freeway main line. When exchange of traffic between
freeways is the basic function, and local access is prohibited by access control restrictions or
traffic volume, separate interchanges for local service may be needed.

1360.02(2) Interchange Patterns

Basic interchange patterns have been established that can be used under certain general
conditions and modified or combined to apply to many more. Consider alternatives in the design
of a specific facility; however, the conditions in the area and on the highway involved govern the
final design of the interchange.

Selection of the final design is based on a study of projected traffic volumes, site conditions,
geometric controls, criteria for intersecting legs and turning roadways, driver expectancy,
consistent ramp patterns, continuity, and cost.

The patterns most frequently used for interchange design are those commonly described as
directional, semi directional, cloverleaf, partial cloverleaf, diamond, and single point (urban)
interchange (see Exhibit 1360-1).
1360.02(2)(a) Directional

A directional interchange is the most effective design for connection of intersecting freeways.
The directional pattern has the advantage of reduced travel distance, increased speed of
operation, and higher capacity. These designs eliminate weaving and have a further advantage
over cloverleaf designs in avoiding the loss of sense of direction drivers experience in traveling a
loop. This type of interchange is costly to construct, commonly using a four-level structure.

1360.02(2)(b) Semi directional

A semi directional interchange has ramps that loop around the intersection of the highways.
This results in multiple single-level structures and more area than the directional interchange.

1360.02(2)(c) Cloverleaf

The full cloverleaf interchange has four loop ramps for the left-turning traffic. Outer ramps
provide for the right turns. A full cloverleaf is the minimum type interchange for a freeway-to-
freeway interchange. Cloverleaf designs often incorporate a C-D road to minimize signing
difficulties and remove weaving conflicts from the main roadway.

The principal advantage of this design is the elimination of all left-turn conflicts with one single-
level structure. Because all movements are merging movements, it is adaptable to any grade
line arrangement.

The cloverleaf has some major disadvantages. The left-turn movement has a circuitous route on
the loop ramp, the speeds are low on the loop ramp, and there are weaving conflicts between
the loop ramps. The cloverleaf also needs a large area. The weaving and the radius of the loop
ramps are a capacity constraint on the left-turn movements.

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1360.02(2)(d) Partial Cloverleaf (PARCLO)

A partial cloverleaf has loop ramps in one, two, or three quadrants that are used to eliminate
the major left-turn conflicts. These loops may also serve right turns for interchanges where
ramp cannot be built in one or two quadrants. Outer ramps are provided for the remaining
turns. Design the grades to provide sight distance between vehicles approaching these ramps.

1360.02(2)(e) Diamond

A diamond interchange has four ramps that are essentially parallel to the major arterial. Each
ramp provides for one right-turn and one left-turn movement. Because left turns are made at
grade across conflicting traffic on the crossroad, intersection sight distance is a primary
consideration.

The diamond design is the most generally applicable and serviceable interchange configuration
and usually has a smaller footprint than any other type. Consider this design first unless another
design is clearly dictated by traffic, topography, or special conditions.
1360.02(2)(f) Single Point Urban (SPUI)

A single point urban interchange is a modified diamond with all of its ramp terminals on the
crossroad combined into one signalized at-grade intersection. This single intersection
accommodates all interchange and through movements.

A single point urban interchange can improve the traffic operation on the crossroad with less
right of way than a typical diamond interchange, but a larger structure.

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Exhibit 1360-1 Basic Interchange Patterns

Directional Semidirectional

Cloverleaf With C-D Roads Diamond

Single Point Urban

Partial Cloverleaf
Interchange (SPUI)

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1360.02(3) Spacing
To avoid excessive interruption of main line traffic, consider each proposed facility in
conjunction with adjacent interchanges, intersections, and other points of access along the
route as a whole.

The minimum spacing between adjacent interchanges is 1 mile in urban areas, 3 miles on the
Interstate in rural areas, and 2 miles on non-Interstate in rural areas (see Exhibit 1360-2). In
urban areas, spacing less than 1 mile may be used with C-D roads or grade-separated (braided)
ramps. Interchange spacing is measured along the freeway centerline between the centerlines
of the crossroads.

The spacing between interchanges may also be dependent on the spacing between ramp
connections. The minimum spacing between the gore noses of adjacent ramps is given in
Exhibit 1360-3.

Exhibit 1360-2 Interchange Spacing

Ramp connection spacing[1]

Interchange spacing: 1 mi min Urban

2 mi min Rural[2]
Gore nose
Notes:
[1] As a minimum, provide length for weaving and signing, but not less than given in Exhibit 1360-3.
[2] 3 miles on the Interstate System.

Consider either frontage roads or C-D roads to facilitate the operation of near-capacity volumes
between closely spaced interchanges or ramp terminals. C-D roads may be needed where
cloverleaf loop ramps are involved or where a series of interchange ramps have overlapping
speed change lanes. Base the distance between successive ramp terminals on capacity. Check
the intervening sections by weaving analyses to determine whether capacity, sight distance, and
effective signing can be provided without the use of auxiliary lanes or C-D roads.

Provide justifications for existing interchanges with less-than-desirable spacing or ramp

connection spacing to remain in place.

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1360.02(4) Route Continuity

Route continuity is providing the driver of a through route a path on which lane changes are
minimized and other traffic operations occur to the right.

In maintaining route continuity, interchange configuration may not favor the heavy traffic
movement, but rather the through route. In this case, design the heavy traffic movements with
multilane ramps, flat curves, and reasonably direct alignment.

1360.02(5) Drainage
Avoid interchanges located in proximity to natural drainage courses. These locations often result
in complex and unnecessarily costly hydraulic structures. The open areas within an interchange
can be used for stormwater detention facilities.

1360.02(6) Uniformity of Exit Pattern

While interchanges are of necessity custom-designed to fit specific conditions, it is desirable that
the pattern of exits along a freeway have some degree of uniformity. From the standpoint of
driver expectancy, it is desirable that each interchange have only one point of exit, located in
advance of the crossroad.

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Exhibit 1360-3 Minimum Ramp Connection Spacing

On-On or Off-Off Off-On Turning Roadways On-Off (Weaving)

L L[1]
L L

System[2] Service[3]
Freeway C-D Road Freeway C-D Road A B C D
Interchange Interchange
1,000 800 500 400 800 600 2000 1600 1600 1000
Gore nose
L = Minimum distance in feet from gore nose to gore nose.
A = Between two interchanges connected to a freeway: a system interchange[2] and a service
interchange.[3]
B = Between two interchanges connected to a C-D road: a system interchange[2] and a service
interchange.[3]
C = Between two interchanges connected to a freeway: both service interchanges.[3]
D = Between two interchanges connected to a C-D road: both service interchanges.[3]
Notes:
These values are based on operational experience, need for flexibility, and signing. Check them in
accordance with Exhibit 1360-12 and the procedures outlined in the Highway Capacity Manual, and
use the larger value.
[1] With justification, these values may be reduced for cloverleaf ramps.
[2] A system interchange is a freeway-to-freeway interchange.
[3] A service interchange is a freeway-to-local road interchange.

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1360.03 Ramps

1360.03(1) Ramp Design Speed

The design speed for a ramp is based on the design speed for the freeway main line.

It is desirable that the ramp design speed at the connection to the freeway be equal to the free-
flow speed of the freeway. Meet or exceed the upper range values from Exhibit 1360-4 for the
design speed at the ramp connection to the freeway. Transition the ramp design speed to
provide a smooth acceleration or deceleration between the speeds at the ends of the ramp.
However, do not reduce the ramp design speed below the lower-range speed of 25 mph. For
loop ramps, use a design speed as high as feasible, but not lower than 25 mph.

These design speed guidelines do not apply to the ramp in the area of the ramp terminal at-
grade intersection. In the area of the intersection, use a design speed of 15 mph for turning
traffic or 0 mph for a stop condition. Use the allowed skew at the ramp terminal at-grade
intersection to minimize ramp curvature.

For freeway-to-freeway ramps and C-D roads, the design speed at the connections to both
freeways is the upper range values from Exhibit 1360-4; however, with justification, the
midrange values from Exhibit 1360-4 may be used for the remainder of the ramp. When the
design speed for the two freeways is different, use the higher design speed.

Existing ramps meet design speed criteria if acceleration or deceleration criteria are met (see
Exhibit 1360-9 or 1360-10) and superelevation meets the criteria in Chapter 1250.
Exhibit 1360-4 Ramp Design Speed

Main Line Design Speed (mph) 50 55 60 65 70 80

Upper Range 45 50 50 55 60 70
Ramp Design
Speed (mph) Midrange 30 40 45 45 50 60
Lower Range 25 25 25 25 25 25

1360.03(2) Sight Distance

Design ramps in accordance with the provisions in Chapter 1260 for stopping sight distances.

1360.03(3) Grade
The maximum grade for ramps for various design speeds is given in Exhibit 1360-5.
Exhibit 1360-5 Maximum Ramp Grade

Ramp Design Speed (mph) 25 – 30 35 – 40 45 and above

Ramp Desirable 5 4 3
Grade (%) Maximum * 7 6 5
* On one-way ramps, downgrades may be 2% greater

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1360.03(4) Cross Section

Provide the ramp widths given in Exhibit 1360-6. Ramp traveled ways may need additional width
when operational needs exist.
Cross slope and superelevation criteria for ramp traveled ways and shoulders are as given in
Chapter 1250 for roadways. At ramp terminals, the intersection lane and shoulder width design
guidance shown in Chapter 1310 may be used.
Whenever feasible, make the ramp cross slope at the ramp beginning or ending station equal to
the cross slope of the through lane pavement. Where space is limited and superelevation runoff
is long, or when parallel connections are used, the superelevation transition may be ended
beyond (for on-ramps) or begun in advance of (for off-ramps) the ramp beginning or ending
station, provided that the algebraic difference in cross slope at the edge of the through lane and
the cross slope of the ramp does not exceed 4%. In such cases, provide smooth transitions for
the edge of traveled way.
Exhibit 1360-6 Ramp Widths

Number of Lanes 1 2
Traveled Way [1] 11-13 [5] 23-25 [3] [5]
Right 4-8 [2] [5] 4-8 [2] [5]
Ramp Width (ft) Shoulders
Left 2 2-4
Medians [4] 6 6-8
Notes:
[1] Evaluate shoulder use to accommodate offtracking, if determined inadequate for
operational performance needs, apply turning roadway widths in Chapter 1240.
[2] Provide width necessary to accommodate offtracking by large vehicles.
[3] Add 12 ft for each additional lane.
[4] The minimum two-way ramp median width (including shoulders) is given. Wider
medians may be required for signs or other traffic control devices and their respective
clearances. When either the on- or off-ramp is single-lane, use the one-lane column. If
both directions are two lanes, use the two-lane column.
[5] Use the mode/function/performance approach described in Chapter 1106 to choose
between the range of widths given.

Ramp shoulders may be used by large trucks for offtracking and by smaller vehicles cutting to
the inside of curves. Evaluate the need to pave shoulders full depth for larger vehicle offtracking
using turn simulation software on one-way ramps to accommodate this type of use. If
operational performance needs demonstrate that accommodation of offtracking on shoulders is
inadequate apply turning roadway widths in Chapter 1240.

1360.03(5) Two-Way Ramps

Two-way ramps are on- and off-ramps on a single roadway. Design two-way ramps as separate
one-way ramps. Provide a raised median to physically separate the on- and off- ramps. Wider
medians than given in Exhibit 1360-6 may be required for signing or other traffic control devices
and their clearances. (For signs, it is sign width plus 4 feet.) Where wider medians are required,
provide a 2-foot clearance between the face of curb and the edge of traveled way. Where
additional width is not required, the raised median width may be reduced to a double-faced

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Interchanges Chapter 1360

mountable or extruded curb. Traffic barrier or a depressed median may be provided in place of
the raised median.

1360.03(6) Ramp Lane Increases

When off-ramp traffic and left-turn movement volumes at the ramp terminal at-grade
intersection cause excessive queue length, it may be desirable to add lanes to the ramp to
reduce the queue length caused by congestion and turning conflicts. Make provision for the
addition of ramp lanes whenever ramp exit or entrance volumes are expected to result in an
undesirable mobility or safety performance. (See Chapter 1210 for width transition design.)

1360.03(7) Ramp Meters

Ramp meters are used to allow a measured or regulated amount of traffic to enter the freeway.
When operating in the “measured” mode, they release traffic at a measured rate to keep
downstream demand below capacity and improve system travel times. In the “regulated” mode,
they break up platoons of vehicles that occur naturally or result from nearby traffic signals. Even
when operating at near capacity, a freeway main line can accommodate merging vehicles one or
two at a time, while groups of vehicles will cause main line flow to break down.

The location of the ramp meter is a balance between the storage and acceleration criteria.
Locate the ramp meter to maximize the available storage and so that the acceleration lane
length, from a stop to the freeway main line design speed, is available from the stop bar to the
merging point. With justification, the average main line running speed during the hours of meter
operation may be used for the highway design speed to determine the minimum acceleration
lane length from the ramp meter. (See 1360.04(4) for information on the design of on-
connection acceleration lanes and Chapter 1050 for additional information on the design of
ramp meters.)

Driver compliance with the signal is required for the ramp meter to have the desired results.
Consider enforcement areas with metered ramps.

Consider HOV bypass lanes with ramp meters. (See Chapter 1410 for design data for ramp meter
bypass lanes.)

1360.04 Interchange Connections

To the extent practicable, provide uniform geometric design and uniform signing for exits and
entrances in the design of a continuous freeway. Do not design an exit ramp as an extension of a
main line tangent at the beginning of a main line horizontal curve.

Provide spacing between interchange connections as given in Exhibit 1360-3.

Avoid on-connections on the inside of a main line curve, particularly when the ramp approach
angle is accentuated by the main line curve, the ramp approach results in a reverse curve to
connect to the main line, or the elevation difference will cause the cross slope to be steep at the
nose.

Keep the use of mountable curb at interchange connections to a minimum.

Provide justification when curb is used adjacent to traffic with a design speed of 40 mph or
higher.

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Exhibit 1360-7a Lane Balance

A C

Merge
B C³A+B-1

F D

Diverge
F = D + E - 1* E

*Note: Number of lanes (F) may increase by one lane, when the lane is an auxiliary lane between closely spaced
entrance and exit ramps.

1360.04(1) Lane Balance

Design interchanges to the following principles of lane balance:

1360.04(1)(a) Entrances

At entrances, make the number of lanes beyond the merging of two traffic streams not less than
the sum of all the lanes on the merging roadways less one (see Exhibit 1360-7a).
1360.04(1)(b) Exits

At exits, make the number of approach lanes equal the number of highway lanes beyond the
exit plus the number of exit lanes less one (see Exhibit 1360-7a). Exceptions to this are:
 At a cloverleaf.
 At closely spaced interchanges with a continuous auxiliary lane between the entrance
and exit.

In these cases, the auxiliary lane may be dropped at a single-lane, one-lane reduction off-
connection (Exhibit 1360-14c), with the number of approach lanes being equal to the sum of the
highway lanes beyond the exit and the number of exit lanes. Closely spaced interchanges have a
distance of less than 2,100 feet between the end of the acceleration lane and the beginning of
the deceleration lane.

Maintain the basic number of lanes, as described in Chapter 1210, through interchanges. When
a two-lane exit or entrance is used, maintain lane balance with an auxiliary lane (see Exhibit
1360-7b). The exception to this is when the basic number of lanes is changed at an interchange.

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Exhibit 1360-7b Lane Balance

3 2 3

2
Undesirable: Lane balance, but no compliance with basic number of lanes.

3 3 3

2
Undesirable: Compliance with basic number of lanes, but no lane balance.

3 4 3 4 3
2

Desirable: Compliance with both lane balance and basic number of lanes.

1360.04(2) Main Line Lane Reduction

The reduction of a basic lane or an auxiliary lane may be made at a two-lane exit or may be
made between interchanges. When a two-lane exit is used, provide a recovery area with a
normal acceleration taper. When a lane is dropped between interchanges, drop it 1,500 to 3,000
feet from the end of the acceleration taper of the previous interchange. This allows for signing
but will not be so far that the driver becomes accustomed to the number of lanes and will be
surprised by the reduction (see Exhibit 1360-8).

Reduce the traveled way width of the freeway by only one lane at a time.

1360.04(3) Sight Distance

Locate off-connections and on-connections on the main line to provide decision sight distance
for a speed/path/direction change as described in Chapter 1260.

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Exhibit 1360-8 Main Line Lane Reduction Alternatives

Lane dropped at two-lane off-connection

Lane between closely spaced ramps

dropped at single-lane off-connection
(lane imbalance for weaving)

500 to 1,000 ft

Lane between closely spaced ramps

dropped after single-lane off-connection
(lane balance for weaving)

500 to 1,000 ft

Lane dropped within interchange

1,500 to 3,000 ft

Lane dropped after interchange

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1360.04(4) On-Connections

On-connections are the paved areas at the end of on-ramps that connect them to the main lane
of a freeway. They have two parts: an acceleration lane and a taper. The acceleration lane
allows entering traffic to accelerate to the freeway speed and evaluate gaps in the freeway
traffic. The taper is for the entering vehicle to maneuver into the through lane.

On-connections are either tapered or parallel. The tapered on-connection provides direct entry
at a flat angle, reducing the steering control needed. The parallel on-connection adds a lane
adjacent to the through lane for acceleration with a taper at the end. Vehicles merge with the
through traffic with a reverse curve maneuver similar to a lane change. While less steering
control is needed for the taper, the parallel is narrower at the end of the ramp and has a shorter
taper at the end of the acceleration lane.

1360.04(4)(a) Acceleration Lane

Provide the minimum acceleration lane length, given in Exhibit 1360-9, for each ramp design
speed on all on-ramps. When the average grade of the acceleration lane is 3% or greater,
multiply the distance from the Minimum Acceleration Lane Length table by the factor from the
Adjustment Factor for Grades table.

For existing ramps that do not have significant crashes in the area of the connection with the
freeway, the freeway posted speed may be used to calculate the acceleration lane length for
Preservation projects. If corrective action is indicated, use the freeway design speed to
determine the length of the acceleration lane.

The acceleration lane is measured from the last point designed at each ramp design speed
(usually the PT of the last curve for each design speed) to the last point of the ramp width.
Curves designed at higher design speeds may be included as part of the acceleration lane length.
1360.04(4)(b) Gap Acceptance

For parallel on-connections, provide the minimum gap acceptance length (Lg) to allow entering
motorists to evaluate gaps in the freeway traffic and position their vehicles to use the gap. The
length is measured beginning at the point that the left edge of traveled way for the ramp
intersects the right edge of traveled way of the main line to the ending of the acceleration lane
(see Exhibits 1360-13b and 13c). The gap acceptance length and the acceleration length overlap,
with the ending point controlled by the longer of the two.

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Exhibit 1360-9 Acceleration Lane Length

Tapered On-Connection Parallel On-Connection

Highway Design Ramp Design Speed (mph)

Speed (mph) 0 15 20 25 30 35 40 45 50 60 70
30 180 140
35 280 220 160
40 360 300 270 210 120
45 560 490 440 380 280 160
50 720 660 610 550 450 350 130
55 960 900 810 780 670 550 320 150
60 1200 1140 1100 1020 910 800 550 420 180
65 1410 1350 1310 1220 1120 1000 770 600 370
70 1620 1560 1520 1420 1350 1230 1000 820 580 210
80 2000 1950 1890 1830 1730 1610 1380 1200 970 590 210

Minimum Acceleration Lane Length (ft)

Upgrade Downgrade
Highway Design
Grade Ramp Design Speed All Ramp Design
Speed (mph)
20 30 40 50 Speeds
40 1.3 1.3 0.70
45 1.3 1.35 0.675
50 3% to less 1.3 1.4 1.4 0.65
55 than 5% 1.35 1.45 1.45 0.625
60 1.4 1.5 1.5 1.6 0.60
70 1.5 1.6 1.7 1.8 0.60
40 1.5 1.5 0.60
45 1.5 1.6 0.575
50 1.5 1.7 1.9 0.55
5% or more
55 1.6 1.8 2.05 0.525
60 1.7 1.9 2.2 2.5 0.50
70 2.0 2.2 2.6 3.0 0.50

Adjustment Factors for Grades Greater Than 3%

Note: Lane widths are shown for illustrative purposes. Determine lane widths based on Exhibit 1360-6.

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1360.04(4)(c) Single-Lane On-Connections

Single-lane on-connections may be either tapered or parallel. The tapered is desirable; however,
the parallel may be used with justification. Design single-lane tapered on-connections as shown
in Exhibit 1360-13a and single-lane parallel on-connections as shown in Exhibit 1360-13b.
1360.04(4)(d) Two-Lane On-Connections

For two-lane on-connections, the parallel is desirable. Design two-lane parallel on-connections
as shown in Exhibit 1360-13c. A capacity analysis will normally be the basis for determining
whether a freeway lane or an auxiliary lane is to be provided.

Justify the use of a two-lane tapered on-connection. Design two-lane tapered on connections in
accordance with Exhibit 1360-13d.

1360.04(5) Off-Connections
Off-connections are the paved areas at the beginning of an off-ramp, connecting it to a main
lane of a freeway. They have two parts: a taper for maneuvering out of the through traffic and a
deceleration lane to slow to the speed of the first curve on the ramp. Deceleration is not
assumed to take place in the taper.

Off-connections are either tapered or parallel. The tapered is desirable because it fits the
normal path for most drivers. When a parallel connection is used, drivers tend to drive directly
for the ramp and not use the parallel lane. However, when a ramp is on the outside of a curve,
the parallel off-connection is desirable. An advantage of the parallel connection is that it is
narrower at the beginning of the ramp.

1360.04(5)(a) Deceleration Lane

Provide the minimum deceleration lane length given in Exhibit 1360-10 for each design speed
for all off-ramps. Also, provide deceleration lane length to the end of the anticipated queue at
the ramp terminal. When the average grade of the deceleration lane is 3% or greater, multiply
the distance from the Minimum Deceleration Lane Length table by the factor from the
Adjustment Factor for Grades table.

For existing ramps that do not have significant crashes in the area of the connection with the
freeway, the freeway posted speed may be used to calculate the deceleration lane length for
Preservation projects. If corrective action is indicated, use the freeway design speed to
determine the length of the deceleration lane.

The deceleration lane is measured from the point where the taper reaches the selected ramp
lane width to the first point designed at each ramp design speed (usually the PC of the first
curve for each design speed). Curves designed at higher design speeds may be included as part
of the deceleration lane length.

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Exhibit 1360-10 Deceleration Lane Length

12 ft Edge of through lane Edge of through lane

12 ft

D e ce D e ce Off-
leratio Off- leratio ram
n la n e ram n lane p
p
A A
First point at each First point at each
ramp design speed ramp design speed

Tapered Off-Connection Parallel Off-Connection

Highway Design Ramp Design Speed (mph)

Speed (mph) 0 15 20 25 30 35 40 45 50 60 70
30 235 200 170 140
35 280 250 210 185 150
40 320 295 265 235 185 155
45 385 350 325 295 250 220 155
50 435 405 385 355 315 285 225 175
55 480 455 440 410 380 350 285 235 180
60 530 500 480 460 430 405 350 300 240
65 570 540 520 500 470 440 390 340 280 185
70 615 590 570 550 520 490 440 390 340 240
80 735 710 690 670 640 610 555 510 465 360 265
Minimum Deceleration Lane Length (ft)

Grade Upgrade Downgrade

3% to less than 5% 0.9 1.2
5% or more 0.8 1.35
Adjustment Factors for Grades Greater Than 3%

Note: Lane widths are shown for illustrative purposes. Determine lane widths based on Exhibit 1360-6.

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1360.04(5)(b) Gores

Gores (see Exhibits 1360-11a and 11b) are decision points. Design them to be clearly seen and
understood by approaching drivers. In a series of interchanges along a freeway, it is desirable
that the gores be uniform in size, shape, and appearance.

The paved area between the physical nose and the gore nose is the reserve area. It is reserved
for the installation of an impact attenuator. The minimum length of the reserve area is
controlled by the design speed of the main line (see Exhibits 1360-11a and 11b).

In addition to striping, raised pavement marker rumble strips may be placed for additional
warning and delineation at gores. (See the Standard Plans for striping and rumble strip details.)

Keep the unpaved area beyond the gore nose as free of obstructions as possible to provide a
clear recovery area. Grade this unpaved area as nearly level with the roadways as possible.
Avoid placing obstructions such as heavy sign supports, luminaire poles, and structure supports
in the gore area.

When an obstruction is placed in a gore area, provide an impact attenuator (see Chapter 1620)
and barrier (see Chapter 1610). Place the beginning of the attenuator as far back in the reserve
area as possible, desirably after the gore nose.

1360.04(5)(c) Single-Lane Off-Connections

For single-lane off-connections, the tapered is desirable. Use the design shown in
Exhibit 1360-14a for tapered single-lane off-connections. Justify the use of a parallel single-lane
off-connection, as shown in Exhibit 1360-14b.
1360.04(5)(d) Single-Lane Off-Connection With One Lane Reduction

The single-lane off-connection with one lane reduction, shown in Exhibit 1360-14c, is used when
the conditions from lane balance for a single-lane exit, one-lane reduction, are met.
1360.04(5)(e) Tapered Two-Lane Off-Connection

The tapered two-lane off-connection design, shown in Exhibit 1360-14d, is desirable where the
number of freeway lanes is reduced or where high-volume traffic operations will be improved by
the provision of a parallel auxiliary lane and the number of freeway lanes is unchanged.

1360.04(5)(f) Parallel Two-Lane Off-Connection

The parallel two-lane off-connection, shown in Exhibit 1360-14e, allows less operational
flexibility than the taper, requiring more lane changes. Justify the use of a parallel two-lane off-
connection.

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Exhibit 1360-11a Gore Area Characteristics

Physical nose Edge of traveled way Edge of shoulder

Painted nose Reserve area [1]

R a mp
Gore nose
Ed g e
o f sh o
ulder

Edge of traveled way

Edge of through lane Edge of shoulder

4 ft min
12 ft [1]
L
1
[2]
Z [2] Z
1 R = 4 ft min[3]
Shoulder plus 2 ft

Shoulder width

Edge of traveled way Edge of shoulder

Single-Lane Off-Connections: No Lane Reduction

Notes:
[1] The reserve area length (L) is not less than:

Main Line Design Speed (mph) 40 45 50 55 60 65 70 80

L (ft) 25 30 35 40 45 50 55 70

Design Speed
[2] Z , design speed is for the main line.
2

[3] Radius may be reduced, when protected by an impact attenuator.

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Exhibit 1360-11b Gore Area Characteristics

Physical nose Edge of traveled way Edge of shoulder

Painted nose Reserve area [1]

R a mp
Gore nose
Ed g e
o f sh o
ulder

Edge of traveled way

Edge of through-lane

4 ft min Edge of shoulder

12 ft
L[1]
1
4 ft
Z [2] 50
[3]
1 R = 4 ft min
Shoulder plus 2 ft

Shoulder width

Edge of traveled way Edge of shoulder

Single-Lane, One-Lane Reduction Off-Connections

and All Two-Lane Off-Connections

Notes:
[1] The reserve area length (L) is not less than:

Main Line Design Speed (mph) 40 45 50 55 60 65 70 80

L (ft) 25 30 35 40 45 50 55 70
[2]
Design Speed
Z
2 , design speed is for the main line.

[3] Radius may be reduced, when protected by an impact attenuator.

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1360.04(6) Collector-Distributor (C-D) Roads

A C-D road can be within a single interchange, through two closely spaced interchanges, or
continuous through several interchanges. Design C-D roads that connect three or more
interchanges to be two lanes wide. Other C-D roads may be one or two lanes in width,
depending on capacity. Consider intermediate connections to the main line for long C-D roads.

a. Exhibit 1360-15a shows the designs for collector-distributor outer separations. Use Design
A, with concrete barrier, when adjacent traffic in either roadway is expected to exceed 40
mph. Design B, with mountable curb, may be used when adjacent posted speed does not
exceed 40 mph.

b. The details shown in Exhibit 1360-15b apply to single-lane C-D road off-connections. Design
a two-lane C-D road off-connection, with the reduction of a freeway lane or an auxiliary
lane, as a normal two-lane off-connection in accordance with 1360.04(5).

c. Design C-D road on-connections in accordance with Exhibit 1360-15c.

1360.04(7) Loop Ramp Connections

Loop ramp connections at cloverleaf interchanges are distinguished from other ramp
connections by a low-speed ramp on-connection, followed closely by an off-connection for
another low-speed ramp. The loop ramp connection design is shown in Exhibit 1360-16. The
minimum distance between the ramp connections is dependent on a weaving analysis. When
the connections are spaced far enough apart that weaving is not a consideration, design the on-
connection in accordance with 1360.04(4) and the off-connection in accordance with
1360.04(5).

1360.04(8) Weaving Sections

Weaving sections may occur within an interchange, between closely spaced interchanges, or on
segments of overlapping routes. Exhibit 1360-12 gives the length of the weaving section for
preliminary design. The total weaving traffic is the sum of the traffic entering from the ramp to
the main line and the traffic leaving the main line to the exit ramp in equivalent passenger cars.
For trucks, a passenger car equivalent of two may be estimated. Use the Highway Capacity
Manual for the final design of weaving sections.

Because weaving sections cause considerable turbulence, interchange designs that eliminate
weaving or remove it from the main roadway are desirable. Use C-D roads for weaving between
closely spaced ramps when adjacent to high-speed highways. C-D roads are not needed for
weaving on low-speed roads.

1360.05 Ramp Terminal Intersections at Crossroads

Design ramp terminal intersections at grade with crossroads as intersections at grade (see
Chapter 1300). Whenever possible, design ramp terminals to discourage wrong-way
movements. Locate ramp terminal intersections at grade with crossroads to provide signal
progression if the intersection becomes signalized in the future. Provide intersection sight
distance as described in Chapters 1310 or 1320.

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Exhibit 1360-12 Length of Weaving Sections

Required weaving length (Lw)

Edge of through lane

2 ft or C-D road 12 ft

PT PC

3000
D

B
LOS

S
LO

LO
Total Weaving Volume, DHV

2000

av in g
f we
mo
eal
t of r
Ou
1000

1000 2000 3000 4000 5000 6000

Length of Weaving Section, Lw (ft)

Lane balanced weaving sections

Lane imbalanced weaving sections

Note:
To determine whether or not lane balance for weaving exists, see Exhibit 1360-8.

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1360.06 Interchanges on Two-Lane Highways

Occasionally, the first stage of a conventional interchange will be built with only one direction of
the main roadway and operated as a two-lane two-way roadway until the ultimate roadway is
constructed.

The design of interchanges on two-lane two-way highways may vary considerably from
traditional concepts due to the following conditions:
 The potential for cross-centerline crashes due to merge conflicts or motorist confusion.
 The potential for wrong-way or U-turn movements.
 Future construction considerations.
 Traffic type and volume.
 The proximity to multilane highway sections that might influence a driver’s impression
that these roads are also multilane.

Provide the deceleration taper for all interchange exit ramps on two-lane highways. Design the
entering connection with either the normal acceleration taper or a “button hook” configuration
with a stop condition before entering the main line. Consider the following items:
 Design the stop condition connection in accordance with a tee (T) intersection as
shown in Chapter 1310. Use this type of connection when an acceleration lane is not
possible. Provide decision sight distance as described in Chapter 1260.
 Since designs may vary from project to project, analyze each project for the most
efficient signing placement, such as one-way, two-way, no passing, do not enter,
directional arrows, guideposts, and traffic buttons.
 Prohibit passing through the interchange area on two-lane highways by means of
signing, pavement marking, or a combination of both. The desirable treatment is a 4
foot median island, highlighted with raised pavement markers and diagonal stripes.
When using a 4-foot median system, extend the island 500 feet beyond any merging
ramp traffic acceleration taper. The width for the median can be provided by reducing
each shoulder 2 feet through the interchange (see Exhibit 1360-17).
 Include signing and pavement markings to inform both the entering and through
motorists of the two-lane two-way characteristic of the main line.
 Use as much of the ultimate roadway as possible. Where this is not possible, leave the
area for future lanes and roadway ungraded.
 Design and construct temporary ramps as if they were permanent unless second-stage
construction is planned to rapidly follow the first stage. Design the connection to meet
the needs of the traffic.

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1360.07 Interchange Plans for Approval

Exhibit 1360-18 is a sample showing the general format and data for interchange design plans.

Compass directions (W-S Ramp) or crossroad names (E-C Street) may be used for ramp
designations.

Include the following, as applicable:

 Design speeds (see Chapter 1103) for main line and crossroads.
 Curve data on main line, ramps, and crossroads.
 Numbers of lanes and widths of lanes and shoulders on main line, crossroads, and
ramps.
 Superelevation diagrams for the main line, the crossroad, and all ramps; these may be
submitted on separate sheets.
 Channelization.
 Stationing of ramp connections and channelization.
 Proposed right of way and access control treatment (see Chapters 510, 520, and 530).
 Delineation of all crossroads, existing and realigned.
 Traffic data for the proposed design; include all movements.
 For HOV direct access connections on the left, include the statement that the
connection will be used solely by HOVs or will be closed.

Prepare a preliminary contour grading plan for each completed interchange. Show the desired
contours of the completed interchange, including details of basic land formation, slopes, graded
areas, or other special features. Coordinate the contour grading with the drainage design and
the roadside development plan.

1360.08 Documentation
Refer to Chapter 300 for design documentation requirements.

1360.09 References

1360.09(1) Design Guidance

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)
Plans Preparation Manual, M 22-31, WSDOT
Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21 01, WSDOT
Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications),
M 41-10, WSDOT

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1360.09(2) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition
A Policy on Design Standards – Interstate System, AASHTO, 2005
Highway Capacity Manual (Special Report 209), Transportation Research Board

Procedure for Analysis and Design of Weaving Sections: A User’s Guide, Jack E. Leisch, October
1985

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Exhibit 1360-13a On-Connection: Single-Lane, Tapered

Notes:

[1] For acceleration lane length LA, see Exhibit 1360-9.

[2] Point A is the point controlling the ramp design speed.

[3] A transition curve with a minimum radius of 3000 ft is desirable. The desirable length is 300 ft. When
the main line is on a curve to the left, the transition may vary from a 3000-ft radius to tangent to the
main line.
[4] Radius may be reduced when concrete barrier is placed between the ramp and main line.
[5] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths,
see Exhibit 1360-6.
[6] Approximate angle to establish ramp alignment.
General: For striping, see the Standard Plans.

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Exhibit 1360-13b On-Connection: Single-Lane, Parallel

A [2]
Acceleration lane LA[1] 300 ft min

12 ft min Edge of through lane

R=4 ft[4]
] 90.0° See paving
[5 Edge of
detail
Lg=300 ft min shoulder
[3].
PT of ramp curve[6]
PCC of End of ramp stationing
Ramp curve

Edge of
through lane

10 ft
8 ft 2 ft

Edge of shoulder

Paving detail

Notes:

[1] For acceleration lane length LA, see Exhibit 1360-9.

[2] Point A is the point controlling the ramp design speed.

[3] A transition curve with a minimum radius of 3000 ft is desirable. The desirable length is 300 ft. When
the main line is on a curve to the left, the transition may vary from a 3000-ft radius to tangent to the
main line. The transition curve may be replaced by a 50:1 taper with a minimum length of 300 ft.
[4] Radius may be reduced when concrete barrier is placed between the ramp and main line.
[5] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths,
see Exhibit 1360-6.
[6] Ramp stationing may be extended to accommodate superelevation transition.

General:
For striping, see the Standard Plans.

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Exhibit 1360-13c On-Connection: Two-Lane, Parallel

A [2]
Acceleration lane LA[1] 300 ft min [7].

24 ft min Edge of through lane

8 ft

R=4 ft[4]
]. 90.0° Edge of
[5 10 ft
shoulder
[3]. Lg=300 ft min
PT of ramp curve[6]
PCC of End of ramp stationing
Ramp curve

Notes:

[1] For acceleration lane length LA, see Exhibit 1360-9.

[2] Point A is the point controlling the ramp design speed.

[3] A transition curve with a minimum radius of 3000 ft is desirable. The desirable length is 300 ft. When
the main line is on a curve to the left, the transition may vary from a 3000-ft radius to tangent to the
main line. The transition curve may be replaced by a 50:1 taper with a minimum length of 300 ft.
[4] Radius may be reduced when concrete barrier is placed between the ramp and main line.
[5] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths,
see Exhibit 1360-6.
[6] Ramp stationing may be extended to accommodate superelevation transition.
[7] Added lane or 1,500-ft auxiliary lane plus 600-ft taper.

General:

For striping, see the Standard Plans.

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Exhibit 1360-13d On-Connection: Two-Lane, Tapered

Notes:

[1] For acceleration lane length LA, see Exhibit 1360-9.

[2] Point A is the point controlling the ramp design speed.

[3] A transition curve with a minimum radius of 3000 ft is desirable. The desirable length is 300 ft. When
the main line is on a curve to the left, the transition may vary from a 3000-ft radius to tangent to the
main line.
[4] Radius may be reduced when concrete barrier is placed between the ramp and main line.
[5] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths,
see Exhibit 1360-6.
[6] Approximate angle to establish ramp alignment.
[7] Added lane or 1,500-ft auxiliary lane plus 600-ft taper.

General:

For striping, see the Standard Plans

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Interchanges Chapter 1360

Exhibit 1360-14a Off-Connection: Single-Lane, Tapered

Notes:

[1] For deceleration lane length LD, see Exhibit 1360-10.

[2] Point A is the point controlling the ramp design speed.

[3] For gore details, see Exhibit 1360-11a.
[4] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths,
see Exhibit 1360-6.
[5] Approximate angle to establish ramp alignment.

General:

For striping, see the Standard Plans.

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Chapter 1360 Interchanges

Exhibit 1360-14b Off-Connection: Single-Lane, Parallel

Notes:

[1] For deceleration lane length LD, see Exhibit 1360-10.

[2] Point A is the point controlling the ramp design speed.

[3] For gore details, see Exhibit 1360-11a.
[4] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths,
see Exhibit 1360-6.
[5] Ramp stationing may be extended to accommodate superelevation transition.
General:

For striping, see the Standard Plans.

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Interchanges Chapter 1360

Exhibit 1360-14c Off-Connection: Single-Lane, One-Lane Reduction

Notes:

[1] For deceleration lane length LD, see Exhibit 1360-10.

[2] Point A is the point controlling the ramp design speed.

[3] For gore details, see Exhibit 1360-11b.

[4] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths,
see Exhibit 1360-6.

[5] Approximate angle to establish ramp alignment.

[6] Auxiliary lane between closely spaced interchanges to be dropped.

General:

For striping, see the Standard Plans.

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Chapter 1360 Interchanges

Exhibit 1360-14d Off-Connection: Two-Lane, Tapered

Notes:

[1] For deceleration lane length LD, see Exhibit 1360-10.

[2] Point A is the point controlling the ramp design speed.

[3] For gore details, see Exhibit 1360-11b.
[4] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths,
see Exhibit 1360-6.
[5] Approximate angle to establish ramp alignment.
[6] Lane to be dropped or auxiliary lane with a minimum length of 1,500 ft with a 300-ft taper.

General:
For striping, see the Standard Plans.

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Interchanges Chapter 1360

Exhibit 1360-14e Off-Connection: Two-Lane, Parallel

Notes:

[1] For deceleration lane length LD, see Exhibit 1360-10.

[2] Point A is the point controlling the ramp design speed.

[3] For gore details, see Exhibit 1360-11b.
[4] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths,
see Exhibit 1360-6.
[5] Ramp stationing may be extended to accommodate superelevation transition.
[6] Lane to be dropped or auxiliary lane with a minimum length of 1,500 ft with a 300-ft taper.

General:
For striping, see the Standard Plans.

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Chapter 1360 Interchanges

Exhibit 1360-15a Collector-Distributor: Outer Separations

Notes:

[1] With justification, the concrete barrier may be placed with 2 ft between the edge of either shoulder
and the face of barrier. This reduces the width between the edge of through-lane shoulder and the
edge of C-D road shoulder to 6 ft and the radius at the nose to 3 ft.

[2] For collector-distributor road lane and shoulder widths, see ramp lane and shoulder widths,
Exhibit 1360-6.

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Interchanges Chapter 1360

Exhibit 1360-15b Collector Distributor: Off-Connections

Notes:

[1] For deceleration lane length LD, see Exhibit 1360-10.

[2] Point A is the point controlling the C-D road or ramp design speed.
[3] For gore details, see Exhibit 1360-11a.
[4] For C-D road and ramp lane and shoulder widths, see Exhibit 1360-6.
[5] Approximate angle to establish alignment.
[6] May be reduced with justification (see Exhibit 1360-15a).

General:
For striping, see the Standard Plans.
Lane and shoulder widths are shown for illustrative purposes. Determine lane and shoulder widths
based on Exhibit 1360-6.

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Chapter 1360 Interchanges

Exhibit 1360-15c Collector Distributor: On-Connections

Notes:

[1] For acceleration lane length LA, see Exhibit 1360-9.

[2] Point A is the point controlling the ramp design speed.

[3] A transition curve with a minimum radius of 3000 ft is desirable. The desirable length is 300 ft. When
the C-D road is on a curve to the left, the transition may vary from a 3000-ft radius to tangent to the
C-D road.
[4] For C-D road and ramp lane and shoulder widths, see Exhibit 1360-6.
[5] Approximate angle to establish alignment.
[6] May be reduced with justification (see Exhibit 1360-15a).
General:
For striping, see the Standard Plans..
Lane and shoulder widths are shown for illustrative purposes. Determine lane and shoulder widths
based on Exhibit 1360-6.

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Interchanges Chapter 1360

Exhibit 1360-16 Loop Ramp Connections

Notes:
[1] For minimum weaving length, see Exhibit 1360-12.
[2] Lane and shoulder widths are shown for illustrative purposes. For minimum ramp lane and shoulder
widths, see Exhibit 1360-6.
[3] For gore details, see Exhibit 1360-11b.

General:
For gore details, see Exhibit 1360-11b.

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Chapter 1360 Interchanges

Exhibit 1360-17 Temporary Ramps

WSDOT Design Manual M 22-01.14 Page 1360-39

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Interchanges Chapter 1360

Exhibit 1360-18 Interchange Plan

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Chapter 1370 Median Crossovers

1370.01 General
1370.02 Analysis
1370.03 Design
1370.04 Plan Updates and Approvals
1370.05 Documentation

1370.01 General
This chapter provides guidance for locating and designing median crossovers.
Median crossovers are provided at locations on divided highways for crossing by
maintenance, traffic service, emergency, and law enforcement vehicles. The use
of all median crossovers is restricted to these users.
Crossovers may be provided:
• Where main line safety will not be compromised by providing a crossover.
• Where access through interchanges or intersections is not practical.
• As part of region maintenance operations.
• As necessary for law enforcement and emergency services functions.
For information about median openings to provide turning movements for public
access to both sides of the roadway, see Chapter 1310, Intersections at Grade.

1370.02 Analysis
A list of existing median crossovers is available from the Headquarters (HQ) Access
and Hearings Section. The Statewide Master Plan for Median Crossovers website is:
 www.wsdot.wa.gov/design/accessandhearings/tracking.htm

The general categories of vehicles recognized as legitimate users of median crossovers

are law enforcement, emergency services, traffic incident response, and maintenance
vehicles.
In urban areas with a high-occupancy vehicle (HOV) lane adjacent to the median,
crossovers may be considered for law enforcement (see Chapter 1410).
In areas where there are 3 or more miles between access points, providing an unobtrusive
crossover can improve emergency services or improve efficiency for traffic services and
maintenance forces.
Maintenance crossovers may be needed at one or both ends of an interchange for the
purpose of winter maintenance operations and at other locations to facilitate maintenance
operations. In general:
• Existing crossovers may remain at their current locations.

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Median Crossovers Chapter 1370

• New crossovers should not be located closer than 1,500 feet to the end of a ramp
taper or to any structure. This distance may be decreased to improve winter
maintenance efficiency based on an operational analysis. Include an operational
analysis in the Design Documentation Package (DDP).
• Crossovers should be located only where stopping sight distance is provided and
preferably should not be located on superelevated curves.

1370.03 Design
Use the following design criteria for all median crossovers, taking into consideration
the intended vehicle usage. Some of these criteria may not apply to crossovers intended
primarily for law enforcement.
• Adequate median width at the crossover location is required to allow the design
vehicle to complete a U-turn maneuver without backing. Use of the shoulder area
is allowed for the execution of the U-turn maneuver. Typical design vehicles for
this determination are a passenger car and a single-unit truck.
• When median barrier is placed in the vicinity of a median crossover, position the
barrier to minimize the potential for errant vehicles to cross through the median.
(See the Standard Plans for typical barrier layout.)
• Consider the types of vehicles using the median crossover.
• The minimum recommended throat width is 30 feet.
• Use grades and radii that are suitable for all authorized user vehicles (see
Chapter 1340).
• In most cases, 10-foot inside paved shoulders are adequate for deceleration and
acceleration lanes. Consider full 10-foot shoulders for a distance of 450 feet upstream
of the crossover area to accommodate deceleration, and extend downstream of the
crossover area for a distance of 600 feet to allow acceleration prior to entering the
travel lane. In cases where the median width is narrower than the design vehicle
turning path, widening shoulders may not provide a benefit. Document decisions
to provide inside shoulders of less than 10 feet.
• Provide adequate stopping sight distance for vehicles approaching the crossover area.
This is due to the unexpected maneuvers associated with these inside access points
and the higher operating speeds commonly experienced in the inside travel lanes
(see Chapter 1260).
• Provide adequate intersection sight distance at crossover locations where authorized
user vehicles must encroach on the travel lanes (see Chapter 1310).
• For the crossing, use sideslopes no steeper than 10H:1V. Grade for a relatively
flat and gently contoured appearance that is inconspicuous to the public.
• Consider impacts to existing drainage.
• Do not use curbs or pavement markings.
• Flexible guideposts may be provided for night reference, as shown in the
Standard Plans.

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Chapter 1370 Median Crossovers

• Consider the terrain and locate the crossover to minimize visibility to the public.
• Use vegetation to minimize the visibility of the crossover. Low vegetation
with a 3-foot year-round maximum height is recommended for this purpose
(see Chapter 900).
• In locations where vegetation cannot be used to minimize visibility by the traveling
public, and there is a high incidence of unauthorized use, use appropriate signing
such as “No U-Turns” to discourage unauthorized use.
• A stabilized all-weather surface is required. Paving of crossings is determined on
a case-by-case basis.

1370.04 Plan Updates and Approvals

All approved crossover locations will be designated on the Statewide Master Plan for
Median Crossovers. Contact the HQ Access and Hearings Section for the following:
• Proposed new crossings
• Relocation of previously approved crossings
• Removal of crossings that are no longer required
Plan updates and approvals involve coordination between the Assistant Regional
Administrator for Operations or Project Development, the Washington State Patrol
(WSP), the HQ Access and Hearings Section, the appropriate Assistant State Design
Engineer (ASDE), and the Federal Highway Administration (FHWA) Area Engineer
(or their designees).
Once locations are identified, the region will send a package to the HQ Access and
Hearings Section, which should include: a strip map showing MP locations of, and
spacing between, existing and/or planned crossovers and interchanges; a justification
for the crossover(s); a copy of any requests for crossovers from the WSP, emergency
services, or maintenance; and a red and green marked-up plan sheet showing locations.
Approval will be given by the ASDE. Construction may not proceed prior to approval.
After notification of approval, the HQ Right of Way Plans Section sends the region
a reproducible revised right of way or limited access plan that includes the approved
crossover location.

1370.05 Documentation
For the list of documents required to be preserved in the Design Documentation Package
and the Project File, see the Design Documentation Checklist:
 www.wsdot.wa.gov/design/projectdev/

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Median Crossovers Chapter 1370

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Chapter 1410 High-Occupancy Vehicle Facilities
1410.01 General
1410.02 Preliminary Design and Planning
1410.03 Operations
1410.04 Design Criteria
1410.05 Documentation
1410.06 References

1410.01 General
High-occupancy vehicle (HOV) facilities include separate HOV roadways, HOV lanes, transit
lanes, HOV direct access ramps, and flyer stops. The objectives for the HOV facilities are:
 Improve the capability of corridors to move more people by increasing the number of
people per vehicle.
 Provide travel time savings and a more reliable trip time to HOV lane users.
 Provide travel options for HOVs without adversely affecting the general-purpose lanes.

Plan, design, and construct HOV facilities that provide intermodal linkages. Give consideration to
future highway system capacity needs. Whenever possible, design HOV lanes so that the level of
service for the general-purpose lanes is not degraded.

In urban corridors that do not currently have planned or existing HOV lanes, complete an
analysis of the need for HOV lanes before proceeding with any projects for additional general-
purpose lanes. In corridors where both HOV and general-purpose facilities are planned,
construct the HOV lane before or simultaneously with the construction of new general-purpose
lanes.

For additional information, see the following chapters:

Chapter Subject
1230 Geometric cross section
1240 General-purpose turning roadway widths
1420 HOV direct access

1410.02 Preliminary Design and Planning

1410.02(1) Planning Elements for Design

In order to determine the appropriate design options for an HOV facility, establish the travel
demand and capacity, identify suitable corridors, evaluate the HOV facility location and length,
and estimate the HOV demand. A viable HOV facility satisfies the following criteria:
 It is part of an overall transportation plan.
 It has the support of the community and public.
 It responds to demonstrated congestion or near-term anticipated congestion: Level of
Service E or F for at least one hour of peak period (traffic approaching a capacity of
1,700 to 2,000 vehicles per hour per lane) or average speeds less than 30 mph during
peak periods over an extended distance.

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High-Occupancy Vehicle Facilities Chapter 1410

 Except for a bypass of a local bottleneck, it is of sufficient length to provide a travel

time saving of at least five minutes during the peak periods.
 It has sufficient numbers of HOV users for a cost-effective facility and avoids the
perception of under-utilization (HOV volumes of 400 to 500 vehicles per hour on
nonseparated lanes and 600 to 800 on separated facilities).
 It provides a safe, efficient, and enforceable operation.

A queue or bottleneck bypass can be effective without satisfying all of the above. An isolated
bypass can be viable when there is localized, recurring traffic congestion, and such treatment
can provide a travel time saving to a sufficient number of HOV users.

The efficiency of the HOV facility can be affected by the access provisions. Direct access
between park & ride/transit facilities and an HOV lane is the most desirable, but it is also an
expensive alternative. Direct access options are discussed in Chapter 1420.

Document the need for the HOV lane and how the proposed lane will meet those needs.

1410.02(2) HOV Facility Type

Make a determination as to the type of HOV lane. The three major choices are: separated
roadway, buffer-separated lane, and nonseparated HOV lane.
1410.02(2)(a) Separated Roadway

The separated roadway can be either a one-way reversible or a two-way operation. The
directional split in the peak periods, available space, and operating logistics are factors to be
considered. A separated HOV roadway may be located in the median of the freeway, next to the
freeway, or on an independent alignment. Separated HOV facilities are more effective for:
 Large HOV volumes.
 Large merging and weaving volumes.
 Long-distance HOV travel.

Reversible separated roadways operate effectively where there are major directional splits
during peak periods. Consider potential changes in this traffic pattern and design the facility to
accommodate possible conversion to a two-way operation. The separated roadway is normally
more efficient, provides for the higher level of safety, and is more easily enforced. However, it is
generally the most expensive type of HOV facility.

1410.02(2)(b) Buffer-Separated Lane

A buffer-separated HOV lane is similar to a freeway nonseparated HOV lane on the left, but with
a buffer between the HOV lane and the general-purpose lanes. The addition of a buffer provides
better delineation between the lanes and controls access between the HOV lane and general-
purpose lanes to improve operations.

1410.02(2)(c) Nonseparated Lane

Nonseparated HOV lanes operate in the same direction and immediately adjacent to the
general-purpose lanes. They are located either to the left (desirable) or to the right of the
general-purpose lanes. Nonseparated HOV lanes are normally less expensive and easier to
implement, and they provide more opportunity for frequent access. However, the ease of access
can create more problems for enforcement and a greater potential for conflicts.

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1410.02(3) Freeway Operational Alternatives
For an HOV lane on a limited access facility, consider the following operational alternatives:
 Inside (desirable) or outside HOV lane
 Lane conversion
 Use of existing shoulder—not recommended for permanent operations
 HOV direct access ramps
 Queue bypasses
 Flyer stops
 Hours of operation

When evaluating alternatives, consider a combination of alternatives to provide the optimum

solution for the corridor. Also, incorporate flexibility into the design in order not to preclude
potential changes in operation, such as changing an outside lane to an inside lane or a reversible
facility to two-way operations. Access, freeway-to-freeway connections, and enforcement will
have to be accommodated for such changes. Document the operational alternatives.
1410.02(3)(a) Inside vs. Outside HOV Lane

System continuity and consistency of HOV lane placement along a corridor are important, and
they influence facility development decisions. Other issues include land use, trip patterns,
transit vehicle service, HOV volume, ramp volume, congestion levels, enforcement, and direct
access to facilities.

The inside (left) HOV lane is most appropriate for a corridor with long-distance trip patterns,
such as a freeway providing mobility to and from a large activity center. These trips are
characterized by long-distance commuters and express transit service. Maximum capacity for an
effective inside HOV lane is approximately 1,500 vehicles per hour. When HOVs weaving across
the general-purpose lanes cause severe congestion, consider providing HOV direct access
ramps, separated HOV roadways, or a higher-occupancy designation. Inside lanes are preferred
for HOV lanes on freeways.

The outside (right) HOV lane is most appropriate for a corridor with shorter, more widely
dispersed trip patterns. These trip patterns are characterized by transit vehicle routes that exit
and enter at nearly every interchange. The maximum capacity for an effective outside HOV lane
is reduced and potential conflicts are increased by heavy main line congestion and large
entering and exiting general-purpose volumes.
1410.02(3)(b) Conversion of a General-Purpose Lane

The use of an existing general-purpose lane for an HOV lane is an undesirable option; however,
conversion of a lane to an HOV lane might be justified when the conversion provides greater
people-moving capability on the roadway. Use of an existing freeway lane as an HOV lane will be
considered only with a Design Analysis.

Given sufficient existing capacity, converting a general-purpose lane to an HOV lane can provide
for greater people moving capability in the future without significantly affecting the existing
roadway operations. The fastest and least expensive method for providing an HOV lane is
through conversion of a general-purpose lane. Restriping and signing are sometimes all that is
needed. Converting a general-purpose lane to HOV use will likely have environmental benefits.

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High-Occupancy Vehicle Facilities Chapter 1410

This method, however, is controversial from a public acceptance standpoint. Public support
might be gained through an effective public involvement program (see Chapter 210).

Do not convert a general-purpose lane to an HOV lane unless it enhances the corridor’s people-
moving capacity. Conduct an analysis that includes:
 Public acceptance of the lane conversion.
 Current and long-term traffic impacts on the adjacent general-purpose lanes and the
HOV lane.
 Impacts to the neighboring streets and arterials.
 Legal, environmental, and safety impacts.

1410.02(3)(c) Use of Existing Shoulder

When considering the alternatives in order to provide additional width for an HOV lane, the use
of the existing shoulder is an undesirable option. Use of the shoulder on a freeway or freeway
ramp as an HOV lane will be considered only with a Design Analysis.

Consider shoulder conversion to an HOV lane when traffic volumes are heavy and the
conversion is a temporary measure. Another alternative is to use the shoulder as a permanent
measure to serve as a transit-only or queue bypass lane during peak hours and then revert to a
shoulder in off-peak hours.

The use of the shoulder creates special signing, operational, and enforcement issues. An
agreement is required with the transit agency to limit transit vehicle use of the shoulder to peak
hours. Provide signing that clearly defines the use of the shoulder. Institute special operations to
clear the shoulder for the designated hours.

The existing shoulder pavement is often not designed to carry heavy volumes of vehicles,
especially transit vehicles. As a result, repaving and reconstruction of the shoulder might be
required.
1410.02(3)(d) HOV Direct Access Ramps

To improve the efficiency of an HOV system, exclusive HOV access connections for an inside
HOV lane may be considered. (See Chapter 1420 for information on HOV direct access
connections.) Direct access reduces the need for HOVs to cross the general-purpose lanes from
right-side ramps. Transit vehicles will be able to use the HOV lane and provide service to park &
ride lots, flyer stops, or other transit stops by the HOV direct access ramps.
1410.02(3)(e) Queue Bypass Lanes

A queue bypass lane allows HOVs to save time by avoiding congestion at an isolated bottleneck.
Consider a queue bypass if the time savings for bypassing HOVs is one minute or more. Typical
locations for queue bypasses are at ramp meters, signalized intersections, toll plazas or ferry
approaches, and locations with isolated main line congestion. Queue bypass lanes can be built
along with a corridor HOV facility or independently. In most cases, they are relatively low cost
and easily implemented.

Where an HOV bypass is being considered at a ramp metering site, consult the Region Traffic
Engineer prior to implementation. When an HOV bypass is constructed at a ramp metering site,
the ramp meter system should be designed to allow for metering the HOV bypass lane as well.
At a minimum, an overhead signal support (Type II) with a tenon position for a signal display for

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 the HOV bypass lane, and sufficient space in the conduit system for additional wiring, should be
provided.
1410.02(3)(f) Flyer Stops

Flyer stops reduce the time required for express transit vehicles to serve intermediate
destinations. However, passengers must travel greater distances to reach the loading platform.
(See Chapter 1420 for information on flyer stops.)
1410.02(3)(g) Hours of Operation

An HOV designation on freeway HOV lanes 24 hours a day provides benefits to users during off-
peak periods, minimizes potential confusion, makes enforcement easier, and simplifies signing
and striping. However, 24-hour operation also might result in a lane not used during off-peak
periods, negative public opinion, and the need for full-time enforcement.

1410.02(4) Arterial Street Operational Alternatives

Arterial street HOV lanes also have a variety of HOV alternatives to be considered. Some of
these alternatives are site-specific or have limited applications. Arterial HOV lanes differ from
freeway HOV lanes in slower speeds, little access control (turning traffic can result in right-angle
conflicts), and traffic signals. Arterial HOV lanes are occasionally designated for transit vehicles
only, especially in cities with a large concentration of transit vehicles. When evaluating
alternatives, consider traffic signal queues and managed access highway class. The alternatives
include the following:
 Type of lane
 Left-side or right-side HOV lane
 Hours of operation
 Spot treatments
 Bus stops

When evaluating alternatives, consider a combination of alternatives to provide the optimum

solution for the corridor. Also, incorporate flexibility into the design in order not to preclude
potential changes in operation. Document the operational alternatives.
1410.02(4)(a) Type of Lane

Lanes can be transit-only or include all HOVs. Transit-only lanes are desirable where bus
volumes are high with a high level of congestion. They increase the speed of transit vehicles
through congested areas and improve the reliability of the transit service. Lanes that allow use
by all HOVs are appropriate on corridors with high volumes of carpools and vanpools. They can
collect carpools and vanpools in business and industrial areas and connect them to the freeway
system.
1410.02(4)(b) Left-Side or Right-Side HOV Lane

Continuity of HOV lane location along a corridor is an important consideration when making the
decision whether to locate an arterial street HOV lane on the left or right side of the street.
Other issues include land use, trip patterns, transit vehicle service, safety, enforcement, and
presence of parking.

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High-Occupancy Vehicle Facilities Chapter 1410

The right side is desirable for arterial street HOV lanes on transit routes with frequent stops. It is
the most convenient for passenger boarding at transit stops. It is also the most common
location for HOV lanes on arterial streets. General-purpose traffic must cross the HOV lane to
make a right turn at intersections and to access driveways. These turns across the HOV lane can
create conflicts. Minimizing access points that create these conflict locations is recommended.
Other issues to consider are on-street parking, stopping areas for delivery vehicles, and
enforcement areas.

Left-side arterial street HOV lanes are less common than right-side lanes. HOV lanes on the left
eliminate the potential conflicts with driveway access, on-street parking, and stopping areas for
delivery vehicles. The result is fewer delays and higher speeds, making left-side arterial street
HOV lanes appropriate for longer-distance trips. The disadvantages include the difficulty
providing transit stops and the need to provide for left-turning general-purpose traffic.

1410.02(4)(c) Hours of Operation

An arterial street HOV lane can either operate as an HOV lane 24 hours a day or during peak
hours only. Factors to consider in determining which to use include type of HOV lane, level of
congestion, continuity, and enforcement.

HOV lanes operating 24 hours a day are desirable when congestion and HOV demand exists for
extended periods throughout the day. The 24-hour operation provides benefits to users during
off-peak periods, minimizes potential confusion, makes enforcement easier, and simplifies
signing and striping. The disadvantages include negative public opinion if the lane is not used
during off-peak periods, the need for full-time enforcement, and the loss of on-street parking.

Peak period HOV lanes are appropriate for arterial streets with HOV demand or congestion
existing mainly during the peak period. Peak period HOV lanes provide HOV priority at the
critical times of the day, lessen negative public perception of the HOV lane, and allow on-street
parking or other shoulder uses at other times. The disadvantages include possible confusion to
drivers, more difficult enforcement, increased signing, and the need to institute special
operations to clear the shoulder or lane for the designated period.
1410.02(4)(d) Spot Treatments

An HOV spot treatment is used to give HOVs priority around a bottleneck. It can provide time
savings, travel time reliability, and improved access to other facilities. Examples include a short
HOV lane to provide access to a freeway on-ramp, one lane of a dual turn lane, a priority lane at
ferry terminals, and priority at traffic signals.

Signal priority treatments that alter the sequence or duration of a traffic signal are techniques
for providing preferential treatment for transit vehicles. The priority treatments can range from
timing and phasing adjustments to signal preemption. Consider the overall impact on traffic.
Preemption would normally not be an appropriate treatment where traffic signal timing and
coordination are being utilized or where there are high traffic volumes on the cross streets.
1410.02(4)(e) Bus Stops

Normally, with arterial HOV lanes, there is not a shoulder suitable for a bus to use while stopped
to load and unload passengers without blocking the lane. Therefore, bus stops are either in-lane
or in a pullout. In-lane bus stops are the simplest type of bus stop. However, stopped buses will
block the HOV lane; therefore, in-lane bus stops are only allowed in transit lanes. Bus pullouts

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 provide an area for buses to stop without blocking the HOV lane. Disadvantages include higher
cost, reduced width for the sidewalk or other roadside area, and possible difficulty reentering
the HOV lane. (See Chapter 1430 for additional information on bus stop location and design.)

1410.03 Operations

1410.03(1) Vehicle Occupancy Designation

Select the vehicle occupancy designation to provide the maximum movement of people in a
corridor, provide free-flow HOV operations, reduce the empty lane perception, provide for the
ability to accommodate future HOV growth within a corridor, and be consistent with the
regional transportation plan and the policies adopted by the Metropolitan Planning
Organization (MPO).

Establish an initial occupancy designation. It is WSDOT policy to use the 2+ designation as the
initial occupancy designation. Consider a 3+ occupancy designation if it is anticipated during
initial operation that the volumes will be 1,500 vehicles per hour for a left-side HOV lane, or
1,200 vehicles per hour for a right-side HOV lane, or that a 45 mph operating speed cannot be
maintained for more than 90% of the peak hour.

1410.03(2) Enforcement
Enforcement is necessary for the success of an HOV facility. Coordination with the Washington
State Patrol (WSP) is critical when the operational characteristics and design alternatives are
being established. This involvement ensures the project is enforceable and will receive their
support.

Provide both enforcement areas and observation points for high-speed HOV lanes and ramp
facilities.

Barrier-separated facilities, because of the limited access, are the easiest facilities to enforce.
Shoulders provided to accommodate breakdowns may also be used for enforcement. Reversible
facilities have ramps for the reverse direction that may be used for enforcement. Gaps in the
barrier may be needed so emergency vehicles can access barrier-separated HOV lanes.

Buffer-separated and nonseparated HOV lanes allow violators to easily enter and exit the HOV
lane. Provide strategically located enforcement areas and observation points.

Consider the impact on safety and visibility for the overall facility during the planning and design
of enforcement areas and observation points. Where HOV facilities do not have enforcement
areas, or where officers perceive that the enforcement areas are inadequate, enforcement on
the facility will be difficult and less effective.

1410.03(3) Intelligent Transportation Systems

The objective of Intelligent Transportation Systems (ITS) is to make more efficient use of our
transportation network. This is done by collecting data, managing traffic, and relaying
information to the motoring public.

It is important that an ITS system be incorporated into the HOV project and that the HOV facility
fully utilize the ITS features available. This includes providing a strategy of incident management

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High-Occupancy Vehicle Facilities Chapter 1410

since vehicle breakdowns and crashes have a significant impact on the efficient operation of the
HOV facilities. (For more information on ITS, see Chapter 1050.)

1410.04 Design Criteria

1410.04(1) Design Procedures

1410.04(2) Design Considerations

HOV lanes are designed to the same criteria as the facilities to which they are attached. Design
nonseparated and buffer-separated HOV lanes to match the vertical alignment, horizontal
alignment, and cross slope of the adjacent lane.

1410.04(3) Adding an HOV Lane

The options for adding an HOV lane are: reconstruction, restriping, combined reconstruction
and restriping, and possibly lane conversion.
1410.04(3)(a) Reconstruction

Reconstruction involves creating roadway width. Additional right of way may be required.
1410.04(3)(b) Restriping

Restriping involves reallocating the existing paved roadway to create enough space to provide
an additional HOV lane.

1410.04(3)(c) Combined Reconstruction and Restriping

Reconstruction and restriping can be combined to maximize use of the available right of way.
For example, a new lane can be created through a combination of median reconstruction,
shoulder reconstruction, and lane restriping. Handle each project on a case-by-case basis.
Generally, consider the following reductions in order of preference:
 Reduction of the inside shoulder width, provided the enforcement and safety
mitigation issues are addressed. (Give consideration to not precluding future HOV
direct access ramps by over-reduction of the available median width.)
 Reduction of the interior general-purpose lane width to 11 feet.
 Reduction of the outside general-purpose lane width to 11 feet.
 Reduction of the HOV lane to 11 feet.
 Reduction of the outside shoulder width to 8 feet.

1410.04(3)(d) Lane Conversion

If lane width adjustments are made, thoroughly eradicate the old lane markings. It is desirable
that longitudinal joints (new or existing) not conflict with tire track lines. If they do, consider
overlaying the roadway before restriping.

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1410.04(4) Design Criteria for Types of HOV Facilities
1410.04(4)(a) Separated Roadway HOV Facilities
The separated HOV facility can be single-lane or multilane and directional or reversible (see
Exhibit 1410-2).
1. Lane Widths
For traveled way width (WR) on turning roadways, see Exhibit 1410-1.
2. Shoulder Widths
The shoulder width requirements are as follows:
 The minimum width for the sum of the two shoulders is 12 feet for one-lane
facilities and 14 feet for two-lane facilities.
 Provide a width of at least 10 feet for one of the shoulders for disabled vehicles.
The minimum for the other shoulder is 2 feet for one-lane facilities and 4 feet for
two-lane facilities.
 The wider shoulder may be on the left or the right. Maintain the wide shoulder on
the same side throughout the facility.
3. Total Widths
To reduce the probability of blocking the HOV facility, make the total width (lane width plus
paved shoulders) wide enough to allow an A BUS to pass a stalled A BUS. For single-lane
facilities, the traveled way widths (WR), given in Exhibit 1410-1, plus the 12-foot total
shoulder width will provide for this passing for radii (R) 100 feet or greater. For R of 75 feet,
a total roadway width of 33 feet is needed, and for R of 50 feet, a total roadway width of 41
feet is needed to provide for the passing.
Exhibit 1410-1 Minimum Traveled Way Widths for Articulated Buses

R (ft)[1] WR (ft)

1-Lane 2-Lane
[2]
3,001 to Tangent 13 24
3,000 14 24
2,000 14 25
1,000 15 26
500 15 27
300 15 28
200 16 29
150 17 31
100 18 34
75 19 37
50 22 45
Notes:
[1] Radius (R) is on the outside edge of traveled
way on 1-lane and centerline on 2-lane roadways.
[2] May be reduced to 12 ft on tangent.

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High-Occupancy Vehicle Facilities Chapter 1410

1410.04(4)(b) Nonseparated Freeway HOV Lanes

For both inside and outside HOV lanes, the minimum lane width is 12 feet and the minimum
shoulder width is 10 feet (see Exhibit 1410-2).

When a left shoulder less than 10 feet wide is proposed for distances exceeding 1.5 miles,
provide enforcement and observation areas at 1- to 2 mile intervals (see 1410.04(7)).

Where left shoulders less than 8 feet wide are proposed for lengths of roadway exceeding 0.5
mile, provide safety refuge areas at 0.5- to 1-mile intervals. These can be in addition to or in
conjunction with the enforcement areas.

Allow general-purpose traffic to cross HOV lanes at on- and off-ramps.

1410.04(4)(c) Buffer-Separated HOV Lanes

Design buffer-separated HOV lanes the same as for inside nonseparated HOV lanes, except for a
buffer 2 to 4 feet in width or 10 feet or greater in width with pavement marking, with
supplemental signing, to restrict crossing. For buffer-separated HOV lanes with a buffer at least
4 feet wide, the left shoulder may be reduced to 8 feet. Buffer widths between 4 and 10 feet are
undesirable because they may appear to be wide enough for a refuge area, but they are too
narrow. Provide gaps in the buffer to allow access to the HOV lane.

1410.04(4)(d) Arterial Street HOV Lanes

The minimum width for an arterial street HOV lane is 12 feet. Allow general-purpose traffic to
cross the HOV lanes to turn at intersections and to access driveways (see Exhibit 1410-2).

For right-side HOV lanes adjacent to curbs, provide a 4-foot shoulder between the HOV lane and
the face of curb. The shoulder may be reduced to 2 feet with justification.

For HOV lanes on the left, a 1-foot left shoulder between the HOV lane and the face of curb is
required. When concrete barrier is adjacent to the HOV lane, the minimum shoulder is 2 feet.
1410.04(4)(e) HOV Ramp Meter Bypass

An HOV bypass may be created by widening an existing ramp, constructing a new ramp where
right of way is available, or reallocating the existing pavement width (provided the shoulders are
full depth). For ramps with a single general purpose lane and an HOV bypass, consider installing
an overhead signal support to allow for the installation of an overhead sign (7.5 square feet
maximum) and a ramp meter display for the HOV bypass. For ramps with two general-purpose
lanes and an HOV bypass, provide an overhead signal support capable of supporting the
installation of a sign (7.5 square feet maximum) and a ramp meter display for the HOV bypass.

Ramp meter bypass lanes may be located on the left or right of metered lanes. Typically, bypass
lanes are located on the left side of the ramp. Consult with local transit agencies and the region
Traffic Office for guidance on which side to place the HOV bypass.

Consider the existing conditions at each location when designing a ramp meter bypass. Design a
single-lane ramp with a single metered lane and an HOV bypass as shown in Exhibit 1410-4a.
Make the total width of the metered and bypass lanes equal to a 2-lane ramp (see Chapters
1240 and 1360). Design a ramp with two metered lanes and an HOV bypass as shown in Exhibit
1410-4b. Make the width of the two metered lanes equal to a 2-lane ramp (see Chapters 1240
and 1360) and the width of the bypass lane as shown in Exhibit 1410-3. The design shown in

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 Exhibit 1410-4b requires that the ramp operate as a single-lane ramp when the meter is not in
operation. Both Exhibits 1410-4a and 4b show an observation point/enforcement area.
Document any other enforcement area designs in the design documentation package. An
alternative is to provide a 10 foot outside shoulder from the stop bar to the main line.

1410.04(5) HOV Direct Access Ramps

HOV direct access ramps provide access between an HOV lane and another freeway, a local
arterial street, a flyer stop, or a park & ride facility. Design HOV direct access ramps in
accordance with Chapter 1420.

1410.04(6) HOV Lane Termination

Locate the beginning and end of an HOV lane at logical points. Provide decision sight distance,
signing, and pavement markings at the termination points.

The desirable method of terminating an inside HOV lane is to provide a straight through move
for the HOV traffic, ending the HOV restriction and dropping a general-purpose lane on the
right. However, analyze volumes for both the HOV lanes and general-purpose lanes, as well as
the geometric conditions, to optimize the overall operational performance of the facility.

1410.04(7) Enforcement Areas

Enforcement of the inside HOV lane can be done with a minimum 10-foot inside shoulder. For
continuous lengths of barrier exceeding 2 miles, a 12-foot shoulder is recommended for the
whole length of the barrier.

For inside shoulders less than 10 feet, locate enforcement and observation areas at 1 to 2-mile
intervals or based on the recommendations of the WSP. These areas can also serve as refuge
areas for disabled vehicles (see Exhibits 1410-5a and 5b).

Provide observation points approximately 1,300 feet before enforcement areas. They can be
designed to serve both patrol cars and motorcycles or motorcycles only. Coordinate with the
WSP during the design stage to provide effective placement and utilization of the observation
points. Median openings give motorcycle officers the added advantage of being able to quickly
respond to emergencies in the opposing lanes (see Exhibit 1410-5b). The ideal observation point
places the motorcycle officer 3 feet above the HOV lane and outside the shoulder so the officer
can look down into a vehicle.

Locate the enforcement area on the right side for queue bypasses and downstream from the
stop bar so the officer can be an effective deterrent (see Exhibits 1410-4a and 4b).

An optional signal status indicator for enforcement may be placed at HOV lane installations that
are metered. The indicator faces the enforcement area so that a WSP officer can determine
whether vehicles are violating the ramp meter. The indicator allows the WSP officer to
simultaneously enforce two areas: the ramp meter and the HOV lane. Consult with the WSP
regarding use at all locations.

For additional information on enforcement signal heads, see the Traffic Manual regarding HOV
metered bypasses.

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High-Occupancy Vehicle Facilities Chapter 1410

1410.04(8) Signs and Pavement Markings

1410.04(8)(a) Signs

Provide post-mounted HOV preferential lane signs next to the HOV lane or overhead-mounted
signs over the HOV lane. Make the sign wording clear and precise, stating which lane is
restricted, the type of HOVs allowed, and the HOV vehicle occupancy designation for that
section of road. The sign size, location, and spacing are dependent upon the conditions under
which the sign is used. Roadside signs can also be used to convey other HOV information such as
the HERO program, carpool information, telephone numbers, and violation fines. Some
situations may call for the use of variable message signs.

Place overhead signs directly over the HOV lane to provide maximum visibility. Use a sequence
of overhead signs at the beginning and end of freeway HOV facilities. Overhead signs can also be
used in conjunction with roadside signs along the roadway.
1410.04(8)(b) Pavement Markings

Provide pavement markings that conform to the Traffic Manual and the Standard Plans.
1410.04(8)(c) Interchanges

In the vicinity of interchange on- and off-connections where merging or exiting traffic crosses an
HOV lane, make provisions for general-purpose traffic using the HOV lane. These provisions
include signing and striping that clearly show the changes in HOV versus general traffic
restrictions. (See the Standard Plans for pavement markings and signing.)

1410.05 Documentation
Refer to Chapter 300 for design documentation requirements.

1410.06 References

1410.06(1) Federal/State Laws and Codes

Revised Code of Washington (RCW) 46.61.165, High-occupancy vehicle lanes

RCW 47.52.025, Additional powers – Controlling use of limited access facilities

–High occupancy vehicle lanes

Washington Administrative Code (WAC) 468-510-010, High occupancy vehicles (HOVs)

1410.06(2) Design Guidance

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21 01, WSDOT

Traffic Manual, M 51-02, WSDOT

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1410.06(3) Supporting Information
Design Features of High-Occupancy Vehicle Lanes, Institute of Traffic Engineers (ITE)

Guide for the Design of High-Occupancy Vehicle Facilities, American Association of State
Highway and Transportation Officials (AASHTO)

High-Occupancy Vehicle Facilities, Parsons Brinkerhoff, Inc., 1990

HOV Systems Manual, NCHRP Report 414, 1998

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High-Occupancy Vehicle Facilities Chapter 1410

Exhibit 1410-2 Typical HOV Lane Sections

[3]

[1] [2] [1]

Separated Roadway

10' 12' [4]

Nonseparated

10'[6] 12' [5] [4]

Buffer-Separated

12'[8] [4] 12'

1'[7] 4'[9]

Arterial HOV

Notes:
[1] The sum of the two shoulders is 12 ft for one-lane and 14 ft for two-lane facilities. Provide
one shoulder with a width of at least 10 ft for disabled vehicles. The wider shoulder may be
on the left or the right. Maintain the wide shoulder on the same side throughout the facility
(see 1410.04(4)(a)2).
[2] 12-ft minimum for single lane, 24-ft minimum for two lanes. Wider width is required on
curves (see 1410.04(4)(a)1 and Exhibit 1410-1).
[3] For total width requirements, see 1410.04(4)(a)3.
[4] Width as required, and the number of lanes.
[5] Buffer 2 to 4 ft or 10 ft or more.
[6] When buffer width is 4 ft or more, may be reduced to 8 ft.
[7] 2 ft when adjacent to concrete barrier.
[8] Arterial HOV lanes on the left operate in the same direction as the adjacent general-purpose
lane.
[9] May be reduced to 2 ft with justification.

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Exhibit 1410-3 Roadway Widths for Two-Lane Ramps With an HOV Lane

Radius of Two-Lane Design Width of

Ramp R (ft) Third Lane[1] W (ft)

1,000 to Tangent 12

999 to 500 13

499 to 250 14

249 to 200 15

199 to 150 16

149 to 100 17

Notes:
[1] Apply additional width to two-lane ramp widths.
[2] For turning roadway widths, see traveled way width for two-lane one-way turning roadways
in Chapter 1240.

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High-Occupancy Vehicle Facilities Chapter 1410

Exhibit 1410-4a Single-Lane Ramp Meter With HOV Bypass

Notes:
[1] For on-connection details and for acceleration lane length, see Chapter 1360.
[2] For ramp lane and shoulder widths for a 2-lane ramp, see Chapters 1240 and 1360.
[3] A transition curve with a minimum radius of 3,000 ft is desirable. The minimum length is 300
ft. When the main line is on a curve to the left, the transition may vary from a 3,000 ft radius
to tangent to the main line.
General:
For striping details, see the Standard Plans.

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Chapter 1410 High-Occupancy Vehicle Facilities

Exhibit 1410-4b Two-Lane Ramp Meter With HOV Bypass

Notes:
[1] For acceleration lane length, see Chapter 1360.
[2] For 2-lane ramp lane and shoulder widths, see Chapters 1240 and 1360. For 3rd lane width, see
Exhibit 1410-3.
[3] A transition curve with a minimum radius of 3000 ft is desirable. The minimum length is 300 ft. When
the main line is on a curve to the left, the transition may vary from a 3000 ft radius to tangent to the
main line.
General:
For striping details, see the Standard Plans.

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High-Occupancy Vehicle Facilities Chapter 1410

Exhibit 1410-5a Enforcement Area: One Direction Only

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Exhibit 1410-5b Enforcement Area: Median

Note:
[1] For median width transition, see Chapter 1210.

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High-Occupancy Vehicle Facilities Chapter 1410

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Chapter 1420 HOV Direct Access
1420.01 General
1420.02HOV Access Types and Locations
1420.03 Direct Access Geometrics
1420.04 Passenger Access
1420.05 Traffic Design Elements
1420.06 Documentation
1420.07 References

1420.01 General
This chapter provides WSDOT design guidance for left-side direct access facilities for high-
occupancy vehicles (HOVs) between freeway HOV lanes and flyer stops within the freeway right
of way or facilities outside of the right of way. Design right-side HOV-only access facilities in
accordance with Chapter 1360.

Direct access eliminates the need for left-side HOV lane users to cross the general-purpose lanes
to right-side general-purpose ramps. Also, transit vehicles can use the HOV lane and provide
service to the HOV direct access facility.

Providing the HOV user access to the inside HOV lane without mixing with the general-purpose
traffic saves the user additional travel time and aids in safety, enforcement, incident handling,
and overall operation of the HOV facility.

Locations for direct access ramps include HOV facilities on intersecting routes, park & ride lots,
flyer stops, and locations with a demonstrated demand. Coordinate with the local transit
agencies to identify these key locations. Give priority to locations that serve the greatest
number of transit vehicles and other HOVs.

1420.01(1) Practical Design

Under WSDOT practical design (see Chapter 1100 and Division 11) an important function of
alternative solution formulation is to identify alternatives that address the baseline need while
balancing the performance trade-offs identified in the process. Since HOV direct access
connections are often added to existing corridors, performance tradeoffs to mainline GP lanes
or other elements may be needed and acceptable to provide the new HOV connections.
Document performance tradeoffs according to Chapter 1100 and Division 11.

1420.01(2) Reviews, Studies, and Reports

The practical design project development process is to be followed when developing an HOV
direct access project(see Chapter 1100). Despite the nature of the projects that are the focus of
this chapter, most facets of the project development process remain unchanged. For example,
early coordination with others is a vital part of developing a project. There are also
environmental considerations, public involvement, and value engineering studies (see Chapter
310). There may also be reviews, studies, and reports required by agreements with regional
transit authorities or other agencies.

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Chapter 1420 HOV Direct Access

Provide an Access Revision Report (ARR) (see Chapter 550) when there is a proposal to add,
delete, or change an access point. Provide the operational analysis from the report for all flyer
stops. For left-side connections, include the commitment that the connection will be used solely
by HOVs or will be closed.

Throughout the project development phase, make sure the project:

• Need Statement (see Chapter 1101) and cost estimate are correct.
• Development process is on schedule.
• Documents are biddable.
• Will be constructible.
• Will be maintainable.

Constructability of HOV direct access facilities is an important consideration during the design
phase. These facilities will typically be constructed on existing highways with traffic maintained
on-site. Key goals are to:
 Provide a project that can be built.
 Plan a construction strategy.
 Provide a safe work zone.
 Minimize construction delays.

Consider access to these facilities by maintenance crews. Avoid items that require a significant
maintenance effort and might result in lane closure for routine maintenance or repair.

1420.01(3) Left-Side Connections

Left-side connections are allowed only when they serve HOVs exclusively and connect to an HOV
lane. The higher traffic volume associated with general-purpose traffic is not acceptable for left-
side connections. If the demand for an HOV direct access decreases to the point that the HOV
direct access connection is no longer desirable, the connection must be closed.

1420.02 HOV Access Types and Locations

To provide direct access for high-occupancy vehicles from the HOV lane to a passenger loading
facility, there are many options and many constraints. Following are some of the options
(selected as being usable on Washington’s freeways) and constraints regarding their use.

To select an option, first establish the need, choose possible locations, evaluate site features
(such as terrain, existing structures, median widths), and evaluate existing HOV information
(such as lanes, park & ride facilities, transit routes and schedules, and origin and destination
studies). Choose a location that meets access point spacing requirements and will not degrade
traffic operations on the main line.

Important constraints to transit stop designs are:

 Passenger access routes and waiting areas are separated from freeway traffic.
 Passenger access to a bus is on its right side only.
 Passenger access to a loading platform must accommodate individuals with disabilities.

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Chapter 1420 HOV Direct Access

1420.02(1) Freeway Ramp Connection Locations

1420.02(1)(a) Spacing

For minimum ramp connection spacing, see Chapter 1360. When evaluating the spacing of left-
side direct access ramps, include only left-side connections.

Traffic operations can be degraded by the weaving caused by a left-side on-connection followed
closely by a right-side off-connection (or a right-side on-connection followed by a left-side off-
connection). As a general rule, if the spacing between the HOV direct access ramp and the
general-purpose ramp is less than one gap acceptance length (see 1420.03(6)(c)) per lane, make
the HOV lane buffer-separated (see Chapter 1410).

Conduct an analysis to make certain that the new ramp will not degrade traffic operations. (See
Chapter 550 for the studies and report required for a new access point.)

When an off-connection follows an on-connection, provide full speed-change lane lengths and
tapers or at least sufficient distance for full speed-change lanes that connect at full width with
no tapers (see 1420.03(6) and (7)). An auxiliary lane can be used to connect full-width speed-
change lanes if there is not sufficient distance for both tapers.
1420.02(1)(b) Sight Distance

Locate both on- and off-connections to the main line where decision sight distance exists on the
main line (see Chapter 1260).

1420.02(2) Ramp Terminal Locations

1420.02(2)(a) Local Streets and Roads

Access to the HOV lane can be provided by a ramp that terminates at a local street or road. The
local street or road may incorporate HOV lanes, but they are not required. (See 1420.05 for
signing and pavement markings.)

Consider traffic operations on the local road. Locate the terminal where:
 It has the least impact on the local road.
 Intersection spacing criteria are satisfied.
 Queues from adjacent intersections do not block the ramp.
 Queues at the ramp do not block adjacent intersections.
 Wrong-way movements are discouraged.

When off-ramps and on-ramps are opposite each other on the local road, consider incorporating
a transit stop with the intersection.
1420.02(2)(b) Park & Ride Lots

HOV direct access ramps that connect the HOV lane with a park & ride lot provide easy access
for express transit vehicles between the HOV lane and a local service transit stop at the park &
ride facility. Other HOV traffic using the access ramp enters through the park & ride lot, which
can create operational conflicts.

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HOV Direct Access Chapter 1420

1420.02(2)(c) Flyer Stops

Median flyer stops do not provide general access to the HOV lane. Access is from the HOV lane
to the transit stop and back to the HOV lane. No other vehicle access is provided. Ramps to and
from the flyer stops are restricted to transit vehicles only.

1420.02(3) Ramp Types

1420.02(3)(a) Drop Ramps

Drop ramps are generally straight, stay in the median, and connect the HOV lane with a local
road or flyer stop. Following is a photo and an example of a drop ramp.

Drop ramp photograph from FHWA/PB HOV Interactive 1.0

High Occupancy Vehicle Data Base from the U.S., Canada, and Europe

Local street

Mirror image ramp on Off-connection

opposite side optional
Freeway
HOV lane

HOV lane
Freeway
Ramp on bridge
or between walls On-connection
in a cut section

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Chapter 1420 HOV Direct Access

Consider this example for gore area characteristics for drop lanes:

Edge of traveled way

Edge of shoulder

R a mp
Painted nose

Edge of traveled way

Ramp shoulder width Edge of ramp traveled way

Impact attenuator

Edge of through HOV lane Concrete barrier

Shoulder width

1420.02(3)(b) T Ramps

A T ramp is a median ramp that

serves all four HOV access
movements and comes to a
T intersection within the median,
usually on a structure. The structure
then carries the HOV ramp over the
freeway to a local road or directly to
a park & ride lot. Through traffic is
not permitted at the T ramp;
therefore, flyer stops are not
allowed. A photo and an example of
a T ramp are shown for reference.
Also, refer to 1420.03(10) for added
design information.

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HOV Direct Access Chapter 1420

Freeway

HOV lane

HOV lane

Freeway

1420.02(3)(c) Flyover Ramps

A flyover ramp is designed to

accommodate high-speed traffic by
using flat curves as the ramp crosses
from the median over one direction
of the freeway to a local road, a park
& ride lot, or an HOV lane on another
freeway. A photo and an example of
a flyover ramp are shown.

Flyover ramp photograph from FHWA/PB HOV Interactive 1.0 High

Occupancy Vehicle Data Base from the U.S., Canada, and Europe

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Chapter 1420 HOV Direct Access

1420.02(4) Transit Stops

1420.02(4)(a) Flyer Stops

Flyer stops are transit stops inside the limited access boundaries for use by express transit
vehicles using the freeway. They may be located in the median at the same grade as the main
roadway or on a structure, on a ramp, or on the right side of the main line.

The advantage of a median flyer stop is that it reduces the time for express transit vehicles to
serve intermediate destinations. A disadvantage is that passengers travel greater distances to
reach the loading platform.

With left-side HOV lanes, flyer stops located on the right side increase the delay to the express
transit vehicles by requiring them to cross the general-purpose lanes. However, these stops
improve passenger access from that side of the freeway.

For additional design information, see Chapter 1430.

1. Side-Platform Flyer Stops

Side-platform flyer stops are normally located

in the median and have two passenger loading
platforms: one on each side between the bus
loading lane and the through HOV lane. This
design provides the most direct movement for
the express transit vehicle and is the desirable
design for median flyer stops.

This design is relatively wide. Where space is a

concern, consider staggering the loading
platforms longitudinally.

Consider tall barrier to divide the directions of

travel or staggering the loading platforms to discourage unauthorized at-grade movement of
passengers from one platform to the other (see 1420.05(1)). The side platform flyer stop with
grade-separated access to each platform is the preferred design.

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2. At-Grade Passenger Crossings

This design is similar to the side-

platform flyer stop, except that
passengers are allowed to cross,
from one platform to the other,
at grade. This design might
eliminate the need for passenger
access to one of the loading
platforms with a ramp or an
elevator, and it simplifies
transfers. The passenger crossing
necessitates providing a gap in
the barrier for the crosswalk.
Only transit vehicles are allowed.
Passenger/ pedestrian At-grade passenger crossing photograph from FHWA/PB HOV Interactive
1.0 High Occupancy Vehicle Data Base from the U.S., Canada, and Europe
accommodations must comply
with the ADA.

Consider an at-grade passenger crossing flyer stop only when passenger volumes are expected
to be low. Design at-grade passenger crossing flyer stops as the first stage of the stop, with the
ultimate design being side-platform flyer stops with grade-separated access to both platforms.

3. Ramp Flyer Stops

When ramp flyer stops are located on an HOV direct access drop ramp, the delay for the express
transit vehicle will not be much more than for a median stop, and passenger access and
connectivity to local service transit routes, on the local street or road, are improved. A flyer stop
on a right-side ramp works well with right-side HOV lanes and diamond interchanges in which
express transit vehicles can use the off-ramp to connect with a bus route on the local road and
the on-ramp to return to the HOV lane. However, a stop on a general-purpose right-side ramp
with a left-side HOV lane will increase the delay by requiring the express transit vehicle to use
the general-purpose lanes and possibly degrade main line traffic operations by increasing
weaving movements.

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1420.02(4)(b) Off-Line Transit Stops

1. Park & Ride Stops

Transit stops located at park & ride lots provide transfer points between the express transit
system and the local transit system, and there is convenient passenger access to the park & ride
lot. When a direct access ramp is provided, express transit delays from the HOV lane to the stop
are reduced. These delays can be reduced more by providing a median flyer stop with passenger
access facilities connecting the park & ride lot to the flyer stop; however, this might be more
inconvenient for the passengers.

2. Stops at Flyer Stop Passenger Access Points

To minimize the passenger travel distance between express and local service transit stops,
locate local system transit stops near passenger access facilities for the flyer stops.

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1420.02(5) Enforcement Areas

Enforcing the vehicle occupancy requirement helps the HOV facilities function as intended. Law
enforcement officers need areas for observation that are near pull-out areas, where both the
violator and the officer can pull safely out of the traffic flow.

Consider locating observation and pull-out areas near any point where violators can enter or
exit an HOV direct access facility. Examples of potential locations are:
 Freeway on- and off-connections for HOV direct access ramps.
 HOV direct access ramp terminals at parking lots.

For freeway HOV lanes, locate enforcement areas on the adjacent shoulders so officers and
violators are not required to cross several lanes of traffic.

Enforcement area guidance and designs are in Chapter 1410.

1420.03 Direct Access Geometrics

HOV direct access ramps are different than other ramps because they are usually on the left side
of the through lanes and they have a high percentage of buses. Design right-side HOV direct
access using the procedures given in Chapter 1360. The following procedures are for the design
of left-side HOV direct access.

Because left-side ramps are rare and therefore less expected, signing is an important issue. (For
signing guidance, see 1420.05(2).)

When the bus percentage is high, there are several considerations:

 When a bus enters the through lanes from the left, the driver has a relatively poor view
of the through traffic.
 A bus requires a longer distance to accelerate than other vehicles.
 A bus requires a longer deceleration length for passenger comfort.

1420.03(1) Design Vehicles

Use the following design vehicles for left-side HOV direct access facilities:
 Use AASHTO’s A BUS vehicle for horizontal design.
 Use AASHTO’s SU-30 vehicle for vertical design.
 Use AASHTO’s P vehicle for stopping sight distance.

Refer to Chapters 1300 and 1430, and the AASHTO Green Book for vehicle descriptions and
dimensions. Use turn simulation software (such as AutoTURN®) to verify turning movements.

1420.03(2) Design Speeds

Refer to Chapter 1360 for the design speeds for ramps. Use the design speed of the general-
purpose lanes for the main line design speed.

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1420.03(3) Sight Distance

Provide stopping sight distance in accordance with Chapter 1260. This provides sight distance
for an automobile. The longer distance needed for a bus to stop is compensated for by the
greater eye height of the driver, with the resulting vertical curve length about equal to that for
an automobile.
Sag vertical curves may be shortened where necessary. (See Chapter 1220 for guidance.)

1420.03(4) Grades
Grades for ramps are covered in Chapter 1360. Design Analyses will be considered for:
 Downgrade on-ramps with grades increased by an additional 1%.
 Upgrade off-ramps with grades increased by an additional 2%.
These increased grades help when geometrics are restricted, and they assist transit vehicles
with the acceleration when entering and the deceleration when exiting the freeway.

1420.03(5) Ramp Widths

1420.03(5)(a) Lane Widths
Use widths for separated roadway HOV facilities. (See Minimum Traveled Way Widths for
Articulated Buses in Chapter 1410.) On tangents, the minimum lane width may be reduced
to 12 feet.

1420.03(5)(b) Shoulder Widths

Ramp shoulder width criteria are modified as follows:
Minimum Ramp Widths for
 The minimum width for the sum of the two Articulated Buses
shoulders is 10 feet for one-lane ramps and 12 feet R (ft)* WR (ft)
for two or more lanes.
Tangent 21
 The minimum width for one of the shoulders is 8
500 23
feet for disabled vehicles. The minimum width for
the other shoulder is 2 feet. (See Chapter 1239 for 400 23
lateral clearance to curb and barrier.) 300 24
 The wider shoulder may be on the left or the right. 200 26
Maintain the wide shoulder on the same side 150 27
throughout the ramp.
100 30
1420.03(5)(c) Total Ramp Widths 75 34
When an A-BUS is the intersection design vehicle at the 50 40
ramp terminal, make the total width of the ramp (lane *R is to the curve inside edge of
width plus shoulders) wide enough to allow an A-BUS to traveled way
pass a stalled A-BUS. This width has two components:
 The vehicle width (U = 8.5 feet on tangent) for each vehicle
 Lateral clearance (C = 2 feet) for each vehicle

The vehicle width and the lateral clearance are about the width of an A-BUS from edge of mirror
to edge of mirror.

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The table above gives the minimum ramp width (WR), including shoulders, at various radii (R) for
an articulated bus. For ramp locations on a tangent section or on a curve with a radius greater
than 150 feet, consider the WR width when requesting a reduced lane or shoulder width. For
ramp curves with a radius less than 150 feet, check the total ramp width and, if necessary,
widen the shoulders to provide the WR width.

1420.03(6) On-Connections
1420.03(6)(a) Parallel On-Connections
For left-side on-connections, use the parallel on-connection.
A parallel on-connection adds a parallel lane that is long enough for the merging vehicle to
accelerate in the lane and then merge with the through traffic. This merge is similar to a lane
change and the driver can use side and rear view mirrors to advantage.

[3] Acceleration lane LA [1] Lg [2] 300 ft

A

See Paving
See note [4] PT of ramp curve
Se e n o Detail
te [5] End of ramp stationing
Edge of
[6] shoulder
90°

Edge of through HOV lane

R=4 ft [9] 12 ft See note [7]

Notes:
[1] For acceleration lane length L A, see 1420.03(6)(b). Check LA for
10 ft [8]
each ramp design speed.
[2] Lg is the gap acceptance length. Begin Lg at the beginning of the
parallel lane, as shown, but not before the end of the
acceleration lane LA. (See 1420.03(6)(c) for the length Lg.) 2 ft
[3] Point A is the point controlling the ramp design speed or the
end of the transit stop zone or other stopping point.
[4] For ramp lane and shoulder widths, see 1420.03(5). Paving Detail
[5] A transition curve with a minimum radius of 3,000 ft is desirable.
The desirable length is 300 ft. When the main line is on a curve to the right, the transition may vary
from a 3,000 ft radius to tangent to the main line. The transition curve may be replaced by a 50:1
taper with a minimum length of 300 ft.
[6] Angle point for width transitions, when required. (See Chapter 1210 for pavement transitions.)
[7] For ramp shoulder width, see 1420.03(5)(b).
[8] The 10 ft left shoulder is the minimum width; 14 ft is desirable. Maintain this shoulder width for at
least 500 ft; 1,000 ft is desirable.
[9] Radius may be reduced when concrete barrier is placed between the ramp and main line.

General:
For striping, see the Standard Plans.

Ramp lane width shown for illustrative purposes. Determine lane width according to 1420.03(5).
Verify ramp width selection with transit providers that may utilize these connections.

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1420.03(6)(b) Acceleration Lanes

The table below gives the minimum acceleration lane length (LA) for left-side HOV direct access
on-connections.

The buses using HOV direct access ramps merge with high-speed traffic. Acceleration lanes that
are longer than normally used are needed.

For left-side on-connections, consider at least the normal 10-foot-wide (14-foot desirable) left
shoulder for the main line for a minimum length of 500 feet (1,000 feet desirable) beyond the
end of the on-connection taper. This gives additional room for enforcement, merging, and
erratic maneuvers.

Last point with ramp

design speed controlling
Accelera
tion lane

On-ra
m p

12 ft
Edge of through HOV lane

Freeway Ramp Design Speed

Speed
(mph) 0 15 20 25 30 35 40 45 50
40 555 480 420 340 185
45 835 760 700 615 470 290
50 1,230 1,160 1,100 1,020 865 685 310
55 1,785 1,715 1,655 1,575 1,420 1,235 875 410
60 2,135 2,085 2,040 1,985 1,875 1,735 1,440 995 460
70 3,045 3,015 2,985 2,945 2,860 2,745 2,465 2,050 1,515
80 4,505 4,465 4,420 4,370 4,250 4,095 3,745 3,315 2,780

Acceleration Length (LA) for Buses (ft)

Notes: For the adjustment factors for grade, see acceleration lane in Chapter 1360.
Ramp lane width shown for illustrative purposes. Determine ramp lane widths according to
1420.03(5). Verify ramp width selection with transit providers that may utilize these connections.

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1420.03(6)(c) Gap Acceptance Length

Gap acceptance length is a minimum distance traveled while a merging driver finds a gap in the
through traffic and begins the merge. For left-side parallel on-connections, the gap acceptance
length is added to the acceleration length. The Lg values are given in the table below. These
values are larger than for right-side on-connections to account for drivers’ visibility constraints.

Highway Posted Gap Acceptance

Speed (mph) Length, Lg (ft)
45 550
50 625
55 700
60 775
65 850
70 925

1420.03(6)(d) Urban On-Connection Design

Design left-side HOV direct access on-connections in urban areas as follows:

1. Use the parallel design for left-side on-connections.
2. Add the Gap Acceptance Length for Parallel On-Connections (see 1420.03(6)(c)) for a
freeway speed of 60 mph to the acceleration length.
3. Use Acceleration Length for Buses (see 1420.03(6)(b)) with a 60 mph freeway speed and the
ramp design speed (see 1420.03(2)) for acceleration length.
1420.03(6)(e) Rural On-Connection Design

Design left-side HOV direct access on-connections in rural areas using mainline design speed.

1420.03(7) Off-Connections
1420.03(7)(a) Parallel Off-Connection

The parallel off-connection is desirable for left-side direct access off-connections. For freeway-to
freeway off-connections, provide a parallel lane with a length sufficient for signing and
deceleration. The desirable minimum length is not less than the gap acceptance length (see
1420.03(6)(c)).

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250 ft Deceleration lane LD [1] A [2]

See Paving
PC of ramp curve
Detail
Begin of ramp stationing See note [3]
Edge of
shoulder [5] 90°

Edge of through HOV lane See note [4] See note [6]
12 ft

Notes:
[7]
[1] For deceleration lane length LD, see 1420.03(7)(c).
Check LD for each ramp design speed.
2 ft
[2] Point A is the point controlling the ramp design
speed or the end of the transit stop zone or other
stopping point.

[3] Ramp lane width shown for illustrative purposes. Determine lane and shoulder widths
according to 1420.03(5). Verify ramp width selection with transit providers that may utilize
these connections.

[4] For ramp shoulder width, see 1420.03(5)(b).

[5] Angle point for width transitions, when required. (See Chapter 1210 for pavement
transitions.)

[6] Gore area characteristics at drop ramp connections are shown on 1420.02(3)(a).
(See Chapter 1360 for gore details at other connection types.)

[7] The desirable shoulder width is 10 ft.

General:
For striping, see the Standard Plans.

1420.03(7)(b) Tapered Off-Connection

The tapered off-connection may be used, with justification. (See Chapter 1360 for the design of
tapered off-connections.)

1420.03(7)(c) Deceleration Lanes

Bus passenger comfort requires longer deceleration lanes. Use the deceleration lane lengths
from the table below for HOV direct access facilities.

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First point with ramp

design speed controlling

tion lane
Decelera mp
Off-ra

12 ft
Edge of through HOV lane

Freeway Ramp Design Speed

Speed
(mph) 0 15 20 25 30 35 40 45 50
40 390 330 290 240 170 100
45 470 420 380 330 260 190 90
50 570 520 480 430 360 290 190 100
55 680 620 590 540 470 400 300 210 110
60 800 740 700 660 580 520 420 330 230
70 990 930 900 850 780 710 610 520 420
80 1,210 1,150 1,110 1,060 990 920 830 740 640
Deceleration Length (LD) for Buses (ft)
Notes: For the adjustment factors for grade, see deceleration lane in Chapter 1360. Ramp lane
width shown for illustrative purposes. Determine lane width according to 1420.03(5). Verify ramp
width selection with transit providers that may utilize these connections.

1420.03(7)(d) Urban Off-Connection Design

Design left-side HOV direct access off-connections in urban areas as follows:

1. Either the parallel (desirable) or the taper (with justification) design may be used.

2. Use the longer deceleration length of: the Deceleration Length for Buses (see 1420.03(7)(c))
from a 60 mph freeway speed to the ramp design speed (see 1420.03(2)) or the Minimum
Deceleration Length given in Chapter 1360 from the freeway design speed to the ramp
design speed.

1420.03(7)(e) Rural Off-Connection Design

Design left-side HOV direct access off-connections in rural areas using mainline design speed.

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1420.03(8) Vertical Clearance

Vertical clearance for a structure over a road is measured from the lower roadway surface,
including the usable shoulders, to the bottom of the overhead structure.

Refer to Chapter 720 for information on vertical clearance.

The minimum vertical clearance for a pedestrian grade separation over any road is 17.5 feet.

1420.03(9) Flyer Stops

Design flyer-stop ramp on-connections as given in 1420.03(6), and design off-connections as
given in 1420.03(7). Flyer stop connections are included in the access point spacing discussed in
1420.02(1)(a).

Design the ramp to the flyer stop in accordance with 1420.03(3), 1420.03(4), and 1420.03(5).

The minimum width for the roadway at a flyer stop is 24 feet.

When a flyer stop is in the median, provide enough median width for the flyer stop roadway,
passenger facilities, and barrier separation without reducing the width of the through lanes or
shoulders (see 1420.04).

The approval of a flyer stop requires the operational analysis portion of the Access Revision
Report (see Chapter 550).

1420.03(10) Wrong-Way Driving Countermeasures

The following bulleted items and examples are countermeasures for wrong-way driving at HOV
direct access ramps:
 Provide a staggered traffic arrow to better describe the left and right turns.
 Provide pavement marking extensions, using wide lines, through intersections.
 Use redundant directional pavement arrows at ramp terminals.
 Paint or use reflective sheeting to highlight barrier terminals.
 Locate the left barrier end to provide good visibility for left-turning traffic for both the
barrier terminal and the on-ramp roadway.
 Extend the right barrier as far as feasible while providing a 4-foot clearance for the left-
turning exiting design vehicle.
 Provide redundant signing.
 Provide enlarged warning signs.

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Provide pavement
marking extensions
Extend right barrier
using wide lines.
and install barrier
terminal with reflective
Locate left barrier end so that sheeting or yellow
left-turning drivers can see and paint for visibility.
recognize both the freeway entrance
and the barrier end. Install barrier Use redundant directional arrows.
terminal with reflective sheeting or
yellow paint for visibility. Provide a staggered traffic arrow.

ONE WAY
ONE WAY
DO NOT

NORTH ENTER

INTERSTATE
ONE WAY
ONE WAY

ONE WAY
FREEWAY WRONG
ENTRANCE WAY

FREEWAY
ENTRANCE

DO NOT
WRONG
WAY
ENTER

ONE WAY

SOUTH Provide individual

INTERSTATE

guide signs for each

movement.

1420.04 Passenger Access

When designing transit stops, include accessibility (compliance with the ADA), safety, and the
comfort of passengers. Minimize pedestrian/vehicle conflict points. Design the whole facility
with security in mind by keeping lines of sight as open as possible. Traffic barriers, fencing,
illumination, landscaping, seating, windscreens, shelters, enclosed walkways, telephones, and
posted schedules are examples of items that contribute to passenger safety and well-being. (See
Chapter 1430 for passenger amenities at transit stops.)

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1420.04(1) Passengers
To encourage use of the passenger access facility for an express transit stop, provide a route
that is the shortest distance to travel from the park & ride lot or local transit stop. Failure to do
so might generate the use of undesirable shortcuts. To encourage local use of the passenger
access facilities, provide direct access from surrounding neighborhoods.

Provide grade separations for pedestrian access to transit stops in the median. Consider
stairways, ramps, elevators, and escalators, but provide at least one access for the individuals
with disabilities at every loading platform, as required by the American with Disabilities Act of
1990. (See Chapter 1510 for guidance when designing pedestrian grade separations.)

The ADA Accessibility Guidelines for Buildings and Facilities states, “Platform edges bordering a
drop-off and not protected by platform screens or guard rails shall have a detectable warning …
24 inches wide running the full length of the platform drop-off.” (See the Standard Plans for the
detectable warning pattern.)

At transit stops, at-grade crosswalks are only permitted in the at-grade crossing flyer stop layout
described in 1420.02(4)(a)2. Use traffic calming techniques, such as horizontal alignment,
textured pavement and crosswalk markings, barrier openings, and other treatments, to
channelize pedestrian movements and slow the transit vehicle’s movements. Illuminate transit
stop crosswalks (see Chapter 1040).

Where at-grade crosswalks are not permitted, take steps to minimize unauthorized at-grade
crossings. Fencing, taller concrete traffic barrier, enclosed walkways, and ramps are examples of
steps that may be taken.

1420.04(2) Bicycles
Bike lanes on nearby streets and separate trails encourage people to bicycle from surrounding
neighborhoods. Provide these bicyclists direct access to passenger access facilities.
Design bicycle access facilities in conjunction with the access for individuals with disabilities (see
Chapters 1510, 1515, and 1520).
Locate bicycle parking outside of the passenger walkways (see Chapter 1430).
Locations near colleges and universities and locations with good bicycle access, especially near
trails, will attract bicyclists. Contact the region Bicycle Coordinator for information on the
predicted number of bicycle parking spaces needed and the types of bicycle racks available.

1420.05 Traffic Design Elements

Traffic design elements are critical to the safe and efficient use of HOV direct access facilities.
The following discusses the elements of traffic design that might be different for HOV direct
access facilities.

1420.05(1) Traffic Barriers

Separate the main line from the HOV direct access facilities with a traffic barrier. Whenever
possible, separate opposing traffic lanes in the facility by using traffic barrier (see Chapter 1610).
This is especially important in areas where opposing traffic is changing speeds to or from main
line speeds. Concrete barrier is generally desirable on these facilities due to lower maintenance
requirements.

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Provide crashworthy end treatments to the approach ends of traffic barriers (see Chapter 1620).

When the operating speed is 25 mph or lower, and where an at-grade pedestrian crossing
transit stop has an opening in a concrete barrier, a sloped-down end as shown in the Standard
Plans is acceptable.

When providing a break in the barrier for turning maneuvers, consider sight distance (see
Chapter 1260) when determining the location for stopping the barrier.

In areas where headlight glare is a concern, consider glare screens such as taller concrete
barrier. Other glare screen options that mount on the top of a barrier tend to be high-
maintenance items and are discouraged.

Taller barrier might also be desirable in areas where pedestrian access is discouraged, such as
between opposing flyer stops or between a flyer stop and the main line.

1420.05(2) Signing
Design and place HOV signing to clearly indicate whether the signs are intended for motorists in
the HOV lane or the general-purpose lanes. The purposes of the signs are to:
 Enhance safety.
 Convey the message that HOV lanes are restricted to HOVs.
 Provide clear directions for entrances and exits.
 Define vehicle occupancy requirements or other restrictions.

Because HOV facilities are not found in many regions, the signing not only considers the
commuter but also the occasional user of the facility who might be unfamiliar with the HOV
facility and its operation.

1420.05(2)(a) Safety

Much of HOV signing relates to enhancing safety for motorists. Not only are geometrics often
minimized due to the lack of right of way, but there are unusual operational characteristics such
as the differential speed between the HOV vehicle and the adjacent general-purpose traffic. To
allow for the lack of passing opportunities in the HOV lane and the necessity for frequent
merging and weaving actions, use messages that are clear and concise, and use symbols
wherever possible.

Because left-side off-connections are unusual, advance warning signing alerting motorists that
an exit is on the left becomes more important.

For T ramps, provide traffic control at the T to assign priority to one of the turn movements and
to avert wrong-way movements.

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1420.05(2)(b) Diamond Symbols

The diamond symbol is used to designate HOV facilities where carpools are allowed. For all
signs, whether regulatory, guide, or warning, the symbol is white on a black background to
convey the restrictive nature of the HOV lane and to make the signs more uniformly
recognizable. The use of the symbol with all HOV signs also informs drivers that the message is
intended for HOVs. The diamond symbol is only for HOV lanes where carpools are allowed; it is
not used for bus, taxi, or bicycle preferential lanes.

1420.05(2)(c) Selection and Location

The signing details given throughout this section provide for the HOV geometric configurations
used within the right of way. Signing for other types of HOV facilities (such as those used for
reversible-flow and for HOV direct access between freeways and temporary HOV lanes used
during construction) is designed on a case-by-case basis and requires consultation with the
appropriate Headquarters and region traffic personnel. In addition to the normal regulatory
signs, include HOV guide signs, both advance and action, in the design of signing for HOV direct
access between freeways.

Notes:
 Place signs in accordance with the MUTCD.
 For non-HOV sign details, see the Sign Fabrication Manual.

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1420.05(2)(d) Regulatory Signs

Regulatory signs for HOV facilities follow the normal regulatory signing principles: black legend
with a white reflective background on a rectangular panel. Keep in mind that messages
conveyed by the HOV signs (such as signs concerning violations and those indicating the
beginning of an HOV lane downstream) are not necessarily intended only for the HOV vehicle.
Therefore, it might be prudent to place additional signs on the right side of the freeway when
doing so conforms to sound engineering practice.

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Guide striping provided for left-hand turns. Do Not Enter sign located on the left side at the
top of each off-ramp.

Keep Right sign located at the top of the median HOV Entrance sign located on the right side at
barrier separating on- and off-ramps. the beginning of each on-ramp.

Wrong Way signs (30° rotation at potential wrong- Diamonds and Turn Only pavement markings on
way entrance point). off-ramps.

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1420.05(2)(e) Guide Signs

Guide signs for HOV facilities are generally used at intermediate on and off locations to inform
HOV motorists of upcoming freeway exits and the appropriate location to exit the HOV lane. For
HOV direct access to and from arterials, guide signs are used in a fashion similar to normal
arterial interchange signing practice. The guide signs for HOV facilities have a black nonreflective
legend on a white reflective background. The exception is the diamond, where the white
reflective symbol is on a black nonreflective background. For all HOV-related guide signs, the
diamond is placed in the upper left-hand corner of the sign.

Notes:
 Sign placement shall be in accordance with the MUTCD.
 For non-HOV sign details, see the Sign Fabrication Manual.

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1420.05(3) Lighting
Provide illumination of HOV direct access ramps, loading platforms at transit stops, major
parking lots, and walkways as defined in Chapter 1040.

1420.05(4) Intelligent Transportation Systems

Intelligent Transportation Systems (ITS) are used to collect traffic data, maintain freeway flow,
and disseminate traveler information. Transit information systems for passengers and transit
facility surveillance are not normally a part of WSDOT’s system, but implementation of these
components may be considered for some locations.

Fully utilize available ITS elements in the design of HOV direct access facilities. Need for ITS
elements varies depending on project features, such as facility design and operation, and
whether the site has existing ITS components.

ITS elements that might be applicable to HOV direct access facilities include: closed circuit
television surveillance; ramp metering; data collection; exit queue detection and override;
dynamic signing; transit signal priority; and automatic vehicle identification and location.

Guidance on the development of ITS elements is found in Chapter 1050. Include the region
Traffic Office, transit operator, and affected local agency in the coordination for the design and
implementation of ITS.

1420.06 Documentation
Refer to Chapter 300 for design documentation requirements.

1420.07 References

1420.07(1) Federal/State Laws and Codes

Americans with Disabilities Act of 1990 (ADA) (28 Code of Federal Regulations [CFR] Part 36,
Appendix A, as revised July 1, 1994)

Washington Administrative Code (WAC) 468-510-010, High occupancy vehicles (HOV)

1420.07(2) Design Guidance

ADA Field Guide for Accessible Public Rights of Way, WSDOT
ADA Standards for Accessible Design, U.S. Department of Justice (USDOJ), 2010; consists of 28
CFR parts 35 & 36 and the ADA and Architectural Barriers Act (ABA) Accessibility Guidelines for
Buildings and Facilities (ADA-ABAAG; also referred to as the 2004 ADAAG), July 23, 2004, U.S.
Access Board. (For buildings and on-site facilities; applies to new construction or alterations as
of March 15, 2012.)
 www.access-board.gov/guidelines-and-standards
ADA Standards for Transportation Facilities, USDOT, 2006; consists of 49 CFR Parts 37 & 38 and
the ADA and ABA Accessibility Guidelines for Buildings and Facilities (ADA-ABAAG; also referred
to as the 2004 ADAAG), July 23, 2004, U.S. Access Board as modified by USDOT. (For transit, light
rail, and similar public transportation facilities.)
 www.access-board.gov/guidelines-and-standards

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Chapter 1420 HOV Direct Access

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

Revised Draft Guidelines for Accessible Public Rights-of-Way (PROWAG), November 23, 2005,
U.S. Access Board. The current best practices for evaluation and design of pedestrian facilities
in the public right of way per the following FHWA memoranda:
 www.fhwa.dot.gov/environment/bikeped/prwaa.htm
 www.fhwa.dot.gov/civilrights/memos/ada_memo_clarificationa.htm
 http://www.access-board.gov/guidelines-and-standards

Sign Fabrication Manual, M 55-05, WSDOT

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

1420.07(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO

FHWA/PB, HOV Interactive 1.0 High Occupancy Vehicle Data Base from the U.S., Canada and
Europe (CD ROM), USDOT, FHWA and Parsons Brinkerhoff

Bus Use of Highways: Planning and Design Guidelines, NCHRP 155

Guide for the Design of High-Occupancy Vehicle (HOV) Facilities, AASHTO

High-Occupancy Vehicle Facilities: A Planning, Design, and Operation Manual, Parsons

Brinckerhoff

HOV Systems Manual, NCHRP 414

“Transit Implications of HOV Facility Design,” WA-RD 396.1, September 1996, WSDOT and
USDOT, Federal Transit Administration

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Chapter 1430 Transit Facilities
1430.01 General
1430.02 Bus Stops and Pullouts
1430.03 Passenger Amenities
1430.04 Park and Ride Lots
1430.05 Transfer/Transit Centers
1430.06 Roadway and Intersection Design
1430.07 Documentation
1430.08 References

1430.01 General
This chapter provides general siting and design information for transit facilities. It is intended for
Washington State Department of Transportation (WSDOT) engineering and planning staff, local
transit providers, developers, and local agencies engaged in the collaborative development of
transit facilities on or adjacent to state highways.

The main points covered in this chapter are:

• Bus Stop Policy: WSDOT’s policy for developing bus stops on state highways is
presented. The policy calls for WSDOT and the transit provider to work together to
locate stops on state highways. Bus stop placement considerations are also provided.
• Park and Ride Lots: Basic guidelines for development of park and ride lots are
presented.
• Transit/Transfer Centers: Guidance on these centers is provided. Guidance in the Park
and Ride section may apply as well.
• Universal Access: The requirements of the Americans with Disabilities Act (ADA) apply
to bus stops and shelters, park and ride lots, and transit centers. This information is
presented in various sections of the chapter, with additional references provided.
• Tools and Resources: Additional guidance and criteria are recommended and
referenced, such as: other chapters in the Design Manual for designing intersections
and road approaches; the Roadside Manual for parking lot design; the local transit
authority’s own standards; and AASHTO.

The design and planning information that follows supports the development of public transit
infrastructure and services on state highways.

Design Manual topics and chapters commonly used in conjunction with this chapter include:
• Right of way and access control: Chapters 510 through 560.
• Intersections and road approaches: Chapters 1300 through 1370.
• Americans with Disabilities Act (ADA) and sidewalk design: Chapter 1510.
• High-occupancy vehicle (HOV) facilities: Chapters 1410 and 1420.

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1430.02 Bus Stops and Pullouts

WSDOT’s Modal Integration Goal seeks to optimize existing system capacity through better
interconnectivity of all transportation modes. In support of this goal, WSDOT promotes safe and
efficient public transportation services on state highways, including transit routes and stops.

On limited access facilities, bus stops are only allowed at designated locations, such as flyer
stops. (See Chapters 520, 530, and 540 for access control policy and guidance.)

Bus stops may be approved on non-limited access facilities at the transit agency’s request and
upon formal review by WSDOT for sight distance and universal access requirements at the
proposed location. At a transit agency’s option, a bus stop on these highways may be located
either within the travel lane, or outside the travel lane in a pullout. Contact the State Traffic
Engineer for information on how to process a transit agency proposal for either an in-lane or
pullout bus stop and for more information about the approval process.

Refer to WAC 468-46, Transit Vehicle Stop Zones, for additional details.

The bus stop is the point of contact between the passenger and the transit services. The
simplest bus stop is a location by the side of the road. The highest quality bus stop is an area
that provides passenger amenities and protection from the weather. Bus stops are typically
maintained by the transit agency. The bus boarding and alighting pad, the path to the shelter,
and the area within the shelter must meet the requirements for universal access. Coordinate
with the local transit agency regarding the location and what type of bus stop to use.

For additional information on bus stop treatments, see Understanding Flexibility in

Transportation Design – Washington and the transit agency’s standards for treatment.

1430.02(1) Bus Stop Placement Guidelines

The information in this section is offered as an example of good practice, and is not intended to
be binding by either the transit agency or WSDOT.

Placement of bus stops addresses the needs and convenience of transit providers, riders, and
highway or street operations. Basic considerations include:
• The need for safe, secure, and convenient service for patrons
• Access for people with disabilities
• Convenient passenger transfers to other intersecting bus routes or transfer points
• Connection to nearby pedestrian circulation systems
• Presence and width of sidewalks, crosswalks, and curb ramps
• Pedestrian activity through intersections
• Ability of the stop to accommodate transit dwell time and the loading/unloading of
wheel chairs and bicycles
• Adequate curb space for the number of buses expected at the stop at one time
• Ease of reentering traffic stream (if a pullout)
• Design characteristics and operational considerations of the highway or street
• Presence of on-street automobile parking and truck delivery zones
• Traffic control devices near the bus stop, such as signals or stop signs
• Volumes and turning movements of other traffic, including bicycles

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• Proximity and traffic volumes of nearby driveways

• Street grade
• Proximity to rail crossings
• Accommodating transit priority equipment at signalized intersections
• Transit queue bypass at signalized intersections
• Often stops are paired on each side of a highway or street
• Proximity to intersections

Where blocks are exceptionally long or where bus patrons are concentrated well away from
intersections, midblock bus stops and midblock crosswalks may be beneficial. Contact the
Region Traffic Engineer when a midblock bus stop is being considered on a multilane roadway to
determine crossing design details and treatments that may be required. (See Chapter 1510 and
the Traffic Manual for more information on midblock crossings.)

It is common to clearly mark the bus stop as a NO PARKING zone or as a BUS ONLY zone with
signs and/or curb painting.

The remainder of this section discusses three types of bus stops:

• Far-side, with a stop located just past an intersection
• Near-side, with a stop located just prior to an intersection
• Midblock, with a stop located away from an intersection

Exhibit 1430-1 illustrates these three types of stops and provides some general dimensions.
Consult the AASHTO Guide for Geometric Design of Transit Facilities on Highways and Streets for
additional guidelines on bus stop spacing, including information on these types of stops.

Examine each case separately and determine the most suitable location, giving consideration to
service and safety of patrons, efficiency of transit operations, and traffic operation in general.

1430.02(1)(a) Far-Side Bus Stops

Sight distance conditions generally favor far-side bus stops, especially at unsignalized
intersections. A driver approaching a cross street on the through lanes can see any vehicles
approaching from the right. With near-side stops, the view to the right may be blocked by a
stopped bus. Where the intersection is signalized, the bus may block the view of one of the
signal heads.

Advantages:
• Right turns can be accommodated with less conflict.
• Minimum interference is caused at locations where traffic is heavier on the approach
side of the intersection.
• Stopped buses do not obstruct sight distance for vehicles entering or crossing from
a side street.
• At a signalized intersection, buses can often find a gap to enter the traffic stream,
except where there are heavy turning movements onto the street with the bus route.
• Waiting passengers assemble at less-crowded sections of the sidewalk away from the
intersection corners.
• Buses in the bus stop do not obscure traffic control devices or pedestrian movements
at the intersection.

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Disadvantages:
• Intersections may be blocked if other vehicles park illegally in the bus stop or if more
buses than the stop can accommodate arrive at the same time.
• If signal priority is not used, the bus stops at the red light and again at the far-side stop,
interfering with traffic and efficient bus operations.

1430.02(1)(b) Near-Side Bus Stops

Advantages:
• May be considered in cases where a far-side bus stop location does not provide a
secure, convenient, or feasible boarding location for passengers.
• Minimum interference is caused where traffic is heavier on the departure side than on
the approach side of the intersection.
• Less interference is caused where the cross street is a one-way street from right to left.
• Passengers generally exit the bus close to the crosswalk.
• There is less interference with traffic turning onto the bus route street from a side street.

Disadvantages:
• Can cause conflicts with right-turning traffic.
• Buses often obscure sight distance to stop signs, traffic signals, or other control
devices, as well as to pedestrians crossing in front of the bus.
• Where the bus stop is too short to accommodate buses arriving at the same time, the
overflow may obstruct the traffic lane.
• If a queue bypass or bus lane is not used at a signalized intersection, then vehicles
waiting at a red signal may block buses from accessing the bus stop, which will require
the bus to wait through multiple signal cycles to enter and then depart the bus stop.

1430.02(1)(c) Midblock Bus Stops

Midblock stop areas are desirable under the following conditions: where traffic or physical
street characteristics prohibit a near- or far-side stop adjacent to an intersection, or where large
factories, commercial establishments, or other large bus passenger generators exist. Locate a
midblock stop at the far side of a pedestrian crosswalk (if one exists), so that standing buses do
not block an approaching motorist’s view of pedestrians in the crosswalk.

Advantages:
• Buses cause a minimum of interference with the sight distance of both vehicles and
pedestrians.
• Stops can be located adjacent to major bus passenger generators and attractors.
• Allows riders to board buses closest to the crosswalk.

Disadvantages:
• Increases walking distance for passengers crossing at intersections.
• Buses may or may not have difficulty reentering the flow of traffic.
• Driveway access may or may not be negatively impacted.

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Exhibit 1430-1 Bus Zone Dimensions

Far-Side Bus Stop

L

Near-Side Bus Stop

L

Bus
Midblock Bus Stop Parked car

Minimum Lengths for Bus Curb Loading Zones (L)[1]

Loading Zone Length (feet)
Approx. Bus
One-Bus Stop Two-Bus Stop
Length
[2] [3] [4] [2]
Far-Side Near-Side Midblock Far-Side Near-Side[3][4] Midblock
25 65 90 125 90 120 150
30 70 95 130 100 130 160
35 75 100 135 110 140 170
40 80 105 140 120 150 180
60 100 125 160 160 190 220

Notes:
[1] Based on bus 1 ft from curb on 40 ft wide streets. When bus is 0.5 ft from curb, add 20 ft near-side, 15 ft far-
side, and 20 ft midblock. Add 15 ft when street is 35 ft wide, and 30 ft when street is 32 ft wide.
[2] Measured from extension of building line or established stop line. Add 15 ft where buses make a right turn.
[3] Add 30 ft where right-turn volume is high for other vehicles.
[4] Measured from head of bus zone as determined by the transit agency (may depend on ADA considerations).
Add 15 ft where buses make a right turn.

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1430.02(2) Bus Pullouts

When designing a pullout, incorporate a deceleration lane or taper into the pullout, a staging
area for all anticipated buses, and a merging lane or taper exiting the pullout. As roadway
operating speeds increase, increase the taper length accordingly.

Bus Pullout with Longitudinal Island

Exhibit 1430-2 illustrates general dimensions and design features of a bus pullout located along
a road. It could also apply to a pullout integrated at the edge of a park and ride lot or transit
center.

Exhibit 1430-3 illustrates the dimensions and design features of bus pullouts associated with
near-side, far-side, and midblock bus pullouts.

Exhibit 1430-4 illustrates the dimension and design of far-side bus zones and pullouts where
buses stop after making a right turn. Adherence to these designs allows buses to stop with
minimal interference to legally parked vehicles.

Exhibit 1430-2 Pullout for Bus Stop along a Road

120' (2 buses)
Passenger waiting area

Sidewalk Shelter Shelter

Width
varies
4:1* 10' min. 6 :1 *
Bus berths
12' des.
Roadway

*On higher-speed facilities, it may be necessary to provide a greater acceleration/deceleration transition.

Suggested values shown; coordinate designs with the transit agency.

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Exhibit 1430-3 Bus Stop Pullouts: Arterial Streets

Notes:
This exhibit provides some general values; coordinate with transit provider for actual dimensions.
[1] For right-turn lane design, see Chapter 1310.
[2] Based on a 40 ft bus. Add 20 ft for articulated bus. Add 45 ft (65 ft articulated) for each additional bus.

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Exhibit 1430-4 Bus Zone and Pullout After Right Turn

35' 40' * 35'

30'
Far-Side Bus Stop

130' *

Far-Side Bus Pullout

After Right Turn

90' * 40' min

60' Des. Bus
12'
Parked car

50' - 100' R
25' - 50' R * Based on 40' bus. Add 20' for articulated bus.

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1430.03 Passenger Amenities

1430.03(1) Bus Stop Waiting Areas
Bus passengers desire a comfortable place to wait for the bus. Providing an attractive, pleasant
setting for the passenger waiting area is an important factor in attracting bus users.

Important elements of a bus stop include:

• ADA Standards
• Protection from passing traffic
• Lighting
• Security
• Paved surface
• Protection from the environment
• Seating or other street furniture (if the wait may be long)
• Information about routes serving the stop

Providing protection from passing traffic involves locating stops where there is enough space, so
passengers can wait away from the edge of the traveled roadway. The buffering distance from
the roadway increases with traffic speed and traffic volume. Where vehicle speeds are 30 mph
or below, 5 feet is a satisfactory distance. In a heavy-volume arterial with speeds up to 45 mph,
a distance of 10 feet provides passenger comfort.

Passengers arriving at bus stops, especially infrequent riders, want information and reassurance.
Provide information that includes the numbers or names of routes serving the stop. Other
important information may include a system route map, the hours and days of service,
schedules, and a phone number for information. Information technology systems are evolving
and some transit agencies now provide information about wait time until the next bus and
kiosks to purchase the fare before boarding.

Where shelters are not provided, a bus stop sign and passenger bench are desirable, depending
on weather conditions. The sign indicates to passengers where to wait and can provide some
basic route information. The information provided and format used is typically the responsibility
of the local transit agency.

1430.03(2) Passenger Shelters

Passenger shelters provide protection for waiting transit users and create driver awareness of
intermodal connections involving vulnerable users. Locate the shelter conveniently for users,
without blocking the sidewalk or the drivers’ line of sight.

Providing shelters (and footing for shelters) is normally the responsibility of the local transit
agency; it provides for shelter design and footing needs. State motor vehicle funds cannot be
used for design or construction of shelters, except for the concrete pad.

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Lighting can enhance passenger safety and security. Lighting makes the shelter visible to passing
traffic and allows waiting passengers to read the information provided. General street lighting is
usually sufficient. Where streetlights are not in place, consider streetlights or transit shelter
lights. For information on illumination, see Chapter 1040.

A properly drained paved surface is needed so passengers do not traverse puddles and mud in
wet weather. Protection from the environment is typically provided by a shelter, which offers
shade from the sun, protection from rain and snow, and a wind break.

Shelters can range from simple to elaborate. The latter type may serve as an entrance landmark
for a residential development or business complex and be designed to carry through the
architectural theme of the complex. If a non-public transportation entity shelter is provided, its
design and siting must be approved by the local transit agency. The reasons for this approval
include safety, barrier-free design, intermodal connections, and long-term maintenance
concerns.

Consider shelters at bus stops in new commercial and office developments and in places where
large numbers of elderly and disabled persons wait, such as at hospitals and senior centers. In
residential areas, shelters are placed at the highest-volume stops.

In order to use buses that are accessible, bus stops must also be accessible. The nature and
condition of streets, sidewalks, passenger loading pads, curb ramps, and other bus stop facilities
can constitute major obstacles to mobility and accessibility. State, local, public, and private
agencies need to work closely with public transportation officials to provide universal access.

Involve the local transit agency in the bus stop pad design and location so that lifts can actually
be deployed at the site.

In order to access a bus stop, it is important that the path to the stop also be accessible. This can
be accomplished by the use of sidewalks with curb ramps. For sidewalk design and curb ramp
information, see Chapter 1510 and the Standard Plans. Exhibit 1430-5 depicts ADA standards for
bus stop locations.

Exhibit 1430-5 Bus Stop Accessibility Features

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Design bus shelter clear space to meet the requirements found in ADA Standards for
Transportation Facilities.

Passenger shelter showing clear space

For more details, see:

Chapter 3, ADA Standards for Transportation Facilities, United States Access Board
 www.access-board.gov/guidelines-and-standards/transportation/facilities/ada-standards-for-
transportation-facilities/chapter-3-building-blocks
Chapter 8, ADA Standards for Transportation Facilities, United States Access Board
 www.access-board.gov/guidelines-and-standards/transportation/facilities/ada-standards-for-
transportation-facilities/chapter-8-special-rooms,-spaces,-and-elements

1430.04 Park and Ride Lots

Park and ride lots provide parking for people who wish to transfer from private vehicles,
bicycles, and other modes to public transit or carpools/vanpools. Most park and ride lots located
within urban areas are served by transit agencies. Leased lots, such as at churches or shopping
centers, or park and rides in rural locations, may have no bus service and only serve carpools
and vanpools.

HOV facilities are often considered and included in larger park and ride lots, to improve access
for transit and carpools (see Chapter 1410).

Park and ride needs and locations are

determined through planning processes
typically conducted by transit agencies,
WSDOT, and/or RTPOs/MPOs. Once the
need is identified, then the project lead
should be identified. Early and continual
coordination between the project lead
and other stakeholders, authorities,
and agencies is critical.

Park and ride lot

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A Cooperative Agreement is written by Headquarters (HQ) Real Estate Services for the purpose
of assigning maintenance and/or operational responsibilities for a WSDOT park and ride lot to a
transit agency or local governmental agency. (See the Agreements Manual and the HQ Real
Estate Services Cooperative Agreement form.)

When a memorandum of understanding (MOU) or other formal agreement exists that outlines
the design, funding, maintenance, and operation of park and ride lots, it must be reviewed for
requirements pertaining to new lots. If the requirements in the MOU or other formal agreement
cannot be met, the MOU must be renegotiated.

1430.04(1) Site Selection

In determining the location of a park and ride lot, public input is a valuable tool. Estimated
parking demand and other factors determine the size of the lot. Traveler convenience is an
important siting factor. Locations that minimize overall trip travel time are most attractive to
commuters. Park and rides near freeway access tend to be heavily used because they minimize
overall trip travel time for the most people. Freeway proximity makes it easier for transit
authorities to provide frequent route service. Other factors that may affect the initial size of the
park and ride lot may include available land, the state of the economy, energy availability and
cost, perceived congestion, transit service frequency, and environmental controls.

Consider sizing the facility to allow for a conservative first-stage construction with expansion
possibilities. As a rule of thumb, 1 acre can accommodate approximately 90 vehicles in a park
and ride lot. This allows approximately 40% of the area for borders, landscaping, passenger
amenities, bus facilities for larger lots, and future expansion. (See the AASHTO Guide for
Geometric Design of Transit Facilities on Highways and Streets, Appendix E, for complementary
information.)

The local transit authority can give critical input on the need for and design of the park and ride
lot. The comprehensive transit plan may already specify a location, and coordination with the
transit agency will ensure the site works well for transit vehicle access. Good coordination with
the transit agencies through the entire design process is necessary to ensure a well-planned
facility that meets the needs of all modal users.

Develop a list of potential sites to identify properties that can be most readily developed for
parking and that have suitable access. Sources for selecting sites can include State Route
Corridor Sketches and useful tools such as GIS or existing aerial photos, detailed land use maps,
or property maps.

Factors influencing site selection and design of a park and ride facility include:
• Local transit authority master plan
• Regional transportation plan
• Local agency codes
• Ability to use existing underutilized paved parking areas within proximity of the
desired location
• Local public input
• Proximity to demand
• Local traffic operations, characteristics, parking availability, and roadway geometry
• Local government zoning

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• Social and environmental impacts

• Local land use compatibility with current or future development patterns
• Cost and benefit/cost
• Access by all modes of travel
• Security and lighting impacts
• Maintenance
• Stormwater treatment and outfall
• Available utilities
• Existing right of way or sundry site
• Potential for future expansion

Purchasing or leasing property increases costs. Therefore, the first choice is state- or transit-
owned right of way, assuming the other selection criteria are favorable. Also, give prime
consideration to the use of city- or county-owned right of way. Select a site that complements
the current and future land use and highway needs.

Investigate each potential site in the field. The field survey serves to confirm or revise
impressions gained from the office review. When conducting the investigation, consider the
following:
• Physical characteristics of the site
• Current use and zoning of the area
• Land use surrounding the property (such as residential or commercial use)
• Street network and condition of the roadways
• Visibility from adjacent streets to enhance security
• Potential for additional expansion
• Ability to meet ADA requirements and accessibility for motorists and other modes of
travel, including transit
• Proximity of any existing parking facilities (such as church or shopping center parking
lots) that are underutilized during the day
• Potential for joint use of facilities with businesses (such as day care centers or dry
cleaners) or land uses compatible with park and ride patrons
• Congestion and other design considerations
• Avoiding locations that encourage noncommuter use (such as proximity to a high school)

The desirable location for park and ride lot along one-way couplets is between the two one-way
streets, with access from both streets. When this is not achievable, provide additional signing to
guide users to and from the facility.

Establish potential sites, with transit agency input, and complete public meetings and
environmental procedures prior to finalizing the design. Follow the procedures outlined
in Chapter 210.

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1430.04(2) Design Guidance

The remainder of this section covers basic design principles and guidance for park and ride lots.
Design features are to be in compliance with local requirements. In some cases, variances to
local design requirements may be needed to provide for the safety and security of facility users.

Common design components with park and ride lots include:

• Geometric design of access points
• Selection of a design bus type
• Efficient traffic flows, both internal and external circulation, for transit, carpools,
vanpools, pedestrians, and bicycles
• ADA-compliant features
• Parking space layout (including accessible stalls)
• Pavements
• Shelters
• Seating or other street furniture
• Exclusive HOV facilities
• Bicycle facilities
• Motorcycle facilities
• Traffic control devices (including signs, signals, and permanent markings)
• Illumination (within the lot and along the streets)
• Stormwater treatment, drainage, and erosion control
• Security for facility users and vehicles (emergency call boxes or telephones)
• Landscape preservation and development
• Environmental mitigation
• Restroom facilities (for transit drivers only or open to the public)
• Trash receptacles
• Artwork (where required by other agencies)

The degree to which the desirable attributes of any component are sacrificed to obtain the
benefits of another component can only be determined on a site-specific basis. However, these
guidelines present the optimum design elements of each factor.

Large park and ride lots are intended to be transfer points from private automobiles and other
modes to transit buses. The same basic principles are used in designing all park and ride lots.

Park and Ride lots that serve a large number of buses and/or routes may also serve as
Transfer/Transit Centers; in these cases section 1430.05 would also apply.

1430.04(2)(a) Access
Provide for all modes of transport used to arrive at and depart from transit facilities. The six
basic modes are pedestrian, bicycle, motorcycle, automobile, vanpool, and bus.

Coordinate with the local jurisdiction and transit authorities to develop the park and ride lot’s
ingress and egress locations for transit and for other vehicles. Design the access route, circulation
patterns, and return routes to minimize travel time. Exclusive direct connections for buses,
vanpools, and carpools may reduce transit costs and save time for riders.

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Design transit facility access points on intersecting collector or local streets where possible.
Locate the access to avoid the queues from nearby intersections. Provide vehicle storage lanes
for entering and exiting vehicles to ensure ease of access and encourage use of the facility. To
avoid increasing congestion on the highway or the community that the facility serves, locate
entrances and exits where a traffic signal, or other intersection control type (see Chapter 1300),
can be reasonably installed at a later time, if needed.

Entrances and exits to park and rides range in scale from full public intersections to driveways,
depending on contextual factors such as traffic volumes and remoteness. Design access points
using criteria in the 1300 chapter series (Division 13) or other published design guidelines used by
the local agency.

When locating access points on a state highway, see chapters in the 500 series (Division 5) for
information about access control types (managed or limited access) and standard access spacing
and other requirements.

When designing the entrance/exit locations used by buses, start the design using a 15-foot lane
width, and then adjust as needed using the bus design vehicle and turn simulation software
(such as AutoTURN®) to verify the design.

1430.04(2)(b) Internal Circulation

Provide walkways to minimize pedestrian use of a circulation road or an aisle to minimize
pedestrian conflict points with other modes.

Make the pedestrian circulation path from any parking stall to the loading zone as direct as
possible. Where pedestrian movement originates from an outlying part of a large parking lot,
consider a walkway that extends toward the loading zone in a straight line.

For additional criteria for pedestrian

movement, see Design Manual Chapter
1510 and Chapter 630 of the Roadside
Manual.

Locate major vehicular circulation routes

within a park and ride lot at the periphery of
the parking area to minimize vehicle-
pedestrian conflicts. Take care that an
internal intersection is not placed too close
to a street intersection. Consider a separate
loading area with priority parking for
vanpools. Wherever possible, do not mix Pedestrian Access Route
buses and auto circulation.

Close coordination with the local transit authority is critical in the design of internal circulation
for buses and vanpools. Design bus circulation routes to provide for easy movement, with
efficient terminal operations and convenient passenger transfers. Design bus routes within the
internal layout, including entrance and exit driveways, to the turning radius of the design bus
vehicle.

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Additional considerations for internal circulation are:

• Base the general design for the individual user modes on the priority sequence of:
pedestrians, bicycles, feeder buses, and park and ride area.
• Design the different traffic flows (auto, pedestrian, bicycle, and bus) circulating within
the lot to be understandable to all users, and to minimize conflicting movements
between modes.
• Disperse vehicular movements within the parking area by the strategic location of
entrances, exits, and aisles.
• Do not confront drivers with more than one decision at a time.
• Provide clear signing for all modes.
• Make the pedestrian circulation routes ADA-compliant (see Chapter 1510).
• Parking stall and access aisle surfaces shall be even and smooth, with surface slopes
not exceeding 2%.
• Consider future expansion.
• Align parking aisles to facilitate convenient pedestrian movement toward the bus
loading zone.
• Locate the passenger loading zone either in a central location, to minimize the
pedestrian walking distance from the parking area to the loading zone, or near the end
of the facility, to minimize the transit travel time.
• In large lots, you may need to provide more than one waiting area for multiple buses.

1430.04(2)(c) Parking Area Design

Refer to the Roadside Manual for detailed guidance on parking area design. Some general
guidelines follow.

Normally, internal circulation is two way with 90° parking. However, one-way aisles with angled
parking may be advantageous in a smaller lot due to the limited available space or to promote a
specific circulation pattern.

Provide parking for bicycles, motorcycles, and private automobiles, as well as carpools,
vanpools, and buses. Locate accessible parking stalls close to the transit loading and unloading
area. Two accessible parking stalls may share a common access aisle. For information on the
number and design of accessible stalls, see the Roadside Manual and the parking space layouts
in the Standard Plans. Sign accessible parking stalls in accordance with the requirements of RCW
46.61.581. Parking stalls and access aisle surfaces shall be even and smooth, with surface slopes
not exceeding 2%.

Locate the bicycle-parking area relatively close to the transit passenger loading area, separated
from motor vehicles by curbing or other physical barriers, without landscaping that hides the
bike area from view, and with a direct route from the street.
• Design the bike-parking area to discourage pedestrians from inadvertently walking into
the area and tripping. Provide lots that are served by public transit, with lockers or with
a rack that will support the bicycle frame and allow at least one wheel to be locked.
• Consider providing shelters for bicycle racks. For bicycles, the layout normally consists
of stalls 2.5 feet x 6 feet, at 90° to aisles, with a minimum aisle width of 4 feet.
Coordinate decisions to provide bicycle lockers, racks, and shelters with the local
transit authority and the region subject matter experts.

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For more information, see Understanding Flexibility in Transportation Design – Washington. It is

complementary to the content in this chapter, and provides more insights to modal designs,
environment and aesthetics, community engagement, jurisdictional coordination.

1430.04(2)(d) Drainage
Provide sufficient slope for surface drainage, as ponding of water in a lot is undesirable for both
vehicles and pedestrians. This is particularly true in cold climates where freezing may create icy
spots. The maximum grade is 2%. Install curb, gutter, and surface drains and grates where
needed. Coordinate designs for drainage and pedestrian access routes to avoid conflicts.
Coordinate drainage design with the local agency to make sure appropriate codes are followed.
For additional drainage information, see Design Manual Chapter 800 and the Roadside Manual.

1430.04(2)(e) Pavement Design

Design pavement to conform to design specifications for each of the different uses and loadings
that a particular portion of a lot or roadway is expected to handle. Bus lanes are typically
Portland cement concrete pavement. Within the parking area, HMA-type pavements are
typically used. Coordinate the pavement designs with the local transit agency and local
jurisdiction. Consult with the Region Materials Engineer on pavement section requirements.
There may be benefits to permeable pavement if space for stormwater facilities is limited.

1430.04(2)(f) Driver Guidance

Provide a well thought out design for traffic movements within the lot using the proper
pavement markings and signage for safe and efficient use by all users of the lot. Typically,
reflectorized markings for centerlines, lane lines, channelizing lines, and lane arrows are needed
to guide or separate patron and transit traffic. Install park and ride identification signs. For
signing and pavement markings, see Chapters 1020 and 1030 and the MUTCD.

1430.04(2)(g) Shelters
Coordinate with the transit agency on the need, location, design, and installation of pedestrian
shelters. To satisfy local needs, shelters may be individually designed, provided by the transit
agency, or selected from a variety of commercially available designs. These designs must meet
ADA accessibility requirements. Consider the following features in shelter design:
• Select open locations with good visibility for user safety.
• Situate enclosed shelters away from edges of driveways and roadways to keep
users dry.
• Select materials and locations where the bus driver can see waiting passengers.
• Avoid using doors, for ease of maintenance and to limit vandalism opportunities.
• Allow for a small air space along the bottom of the enclosure panels, to permit air
circulation and reduce debris collection.
• Optional features you may provide are: lighting; heat; telephone; static or electronic
travel information (schedules); electronic fare collection equipment; commercial
advertisements for revenue generation; and trash receptacles.

For additional information on passenger amenities, see 1430.03.

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1430.04(2)(h) Illumination, Safety, and Security

Lighting is important from a safety standpoint and as a deterrent to criminal activity in both the
parking area and the shelters. For guidance, see Design Manual Chapter 1040, Chapter 630 of
the Roadside Manual, local agency criteria, and AASHTO.

The Guide for Geometric Design of Transit Facilities on Highways and Streets, AASHTO, 2014,
states: “Security at stations and major stops—both manned and unmanned—should be
achieved by closed circuit television monitoring, provision of call boxes, good visibility and
lighting, police surveillance, and effective designs. Both the actual security and the passengers’
perceptions of security are important for a viable service or operation.” (See the Guide for more
information.)

1430.04(2)(i) Planting Areas

Selectively preserve existing vegetation and provide new plantings to afford a balanced
environment for the park and ride lot user. For guidance and policy, see the Roadside Manual
and the Roadside Policy Manual, respectively.

1430.04(2)(j) Fencing
For fencing guidelines, see Chapter 560 and discuss with the partnering transit agency.

1430.04(2)(k) Maintenance
Maintenance of park and ride lots outside state right of way is the responsibility of the local
transit authority. Negotiate maintenance agreements with local transit authorities or other
appropriate parties during the design phase, to identify the requirements and responsibilities
for the maintenance. A Cooperative Agreement is written by HQ Real Estate Services for the
purpose of assigning maintenance and/or operational responsibilities for a WSDOT park and ride
lot to a transit agency or local governmental agency. (See the Agreements Manual and the HQ
Real Estate Services Cooperative Agreement form.)

Consider the following in the maintenance plan:

• Cost estimate
• Periodic inspection
• Pavement repair
• Traffic control devices (signs and pavement markings)
• Lighting
• Mowing
• Cleaning of drainage structures
• Sweeping/trash pickup
• Landscaping
• Shelters
• Snow and ice control

Understanding Flexibility in Transportation Design – Washington, 2005 provides more

information on many of the above topics.

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1430.05 Transfer/Transit Centers

Transfer/transit centers are large multimodal bus stops where buses on a number of routes
converge to allow riders the opportunity to change buses or transfer to other modes.

Transit centers are frequently major activity centers and serve as destination points.

Many factors dictate the particular needs of each transit center. Design of a transit center
considers such features as passenger volume; number of buses on the site at one time; local
auto and pedestrian traffic levels; and universal access.

Transit agencies generally lead in the development of transfer/transit centers, and their
standards apply. Consult the AASHTO Guide for Geometric Design of Transit Facilities on
Highways and Streets for more comprehensive overviews and design guidelines for these
facilities.

1430.05(1) Bus Platforms

At a transit center where several transit routes converge and where buses congregate (lay over),
multiple bus berths or spaces are typically needed, along with areas where passengers boarding
or alighting the bus can take refuge. Typically, there are several design styles for multi-berth bus
platforms (see AASHTO). Parallel and sawtooth types are described below.

An important aspect in multiple bus berthing is proper signing and marking for the bus bays for
both operators and passengers. Clearly delineate the route served by each bay. Consider
pavement marking to indicate stopping positions. Separate layover bays may be needed for
terminating bus routes, or the layover function can be provided at the passenger platform if the
platform only serves a single route. Consider future service plans and maximize flexibility in the
design of transit center bays and circulation.

Portland cement concrete pavement is desirable for pedestrian walkways on the platform, for
ease of cleaning.

Where buses are equipped with a bicycle rack, provide for the loading and unloading of bicycles.

Exhibit 1430-6 shows typical parallel and sawtooth designs for parking 40-foot buses for
passengers boarding and alighting at a platform. The sawtooth design does not require buses to
arrive or depart in any order.

Exhibit 1430-7 is an example of a platform design that has a combination of parallel and
sawtooth bus berths at a platform. The sawtooth design provides more space-efficient berthing,
as the parallel design shown may require that buses arrive and/or depart in order. Coordinate
the bus berth style and platform design with the local transit authority throughout the design
process, and obtain its concurrence for the final design.

In the design of parallel bus berths, additional roadway width is needed for swing-out
maneuvers if shorter bus loading platforms are utilized. The roadway width and the amount
of lineal space required at the bus platform are directly related where designs allow departing
buses to pull out from the platform around a standing bus. The shorter the berth length
allowed, the wider the roadway. Use turn simulation software (such as AutoTURN®) to verify
the design.

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Considerable length is needed in a parallel design to permit a bus to pass and pull into a
platform in front of a parked bus. Design the bus aisle so that a bus can by-pass another bus
stopped at the platform. The decision to provide a parallel design to accommodate a by-pass
maneuver may depend on how many routes service the location, and the frequency of service.

1430.05(2) Flow/Movement Alternatives

Two primary alternatives for vehicle and passenger movement are possible for transfer centers,
regardless of the type of bus berths used, as shown in Exhibit 1430-6. Buses may line up along
one side of the transfer center. This type of arrangement is generally suitable for a limited
number of buses due to the walking distances for transferring passengers. For a larger number
of buses, an arrangement similar to Exhibit 1430-7 can minimize transfer time by consolidating
the buses in a smaller area.

Consult the AASHTO Guide for Geometric Design of Transit Facilities on Highways and Streets for
more comprehensive overviews and design guidelines.

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Exhibit 1430-6 Bus Berth Design

10' min.
12' des.

[1] [1]
80' 80'

Parallel Design

16'

8'

[1]
40' 15' 10'

[2]
Sawtooth Design

Notes:
[1] Dimensions shown are for a 40-ft bus; adjust the length when designing for a longer bus.
[2] Design shown is an example; contact the local transit agency for additional information.

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Exhibit 1430-7 Design Alternative for a Combination of Bus Berths at a Platform

1430.06 Roadway and Intersection Design

Refer to chapters in the 1100, 1200, and 1300 series (Divisions 11, 12, and 13) for guidance on
roadway and intersection design controls and design elements. Some brief discussions are
provided below.

1430.06(1) Pavement
Coordinate the pavement design (type and thickness) of a transit project, whether initiated by
a public transportation agency or a private entity, with WSDOT or the local agency public works
department, depending on highway, street, or road jurisdiction. These agencies play a major
role in determining the paving section for the particular project.

Consult with the Region Materials Engineer on pavement section requirements.

1430.06(2) Grades
Roadway grades refer to the maximum desirable slope or grade, or the maximum slope based
on the minimum design speed that a 40-foot bus can negotiate efficiently. For roadway grade
guidance, see Chapter 1220 or the Local Agency Guidelines.

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Bus speed on grades is directly related to the weight/horsepower ratio. Select grades that
permit uniform operation at an affordable cost. In cases where the roadway is steep, a climbing
lane for buses and trucks may be needed. For climbing lane guidance, see Chapter 1270. Avoid
abrupt changes in grade due to bus overhangs and ground clearance.

1430.06(3) Lane Widths

Guidance on roadway and lane widths is given in Chapter 1230 or the Local Agency Guidelines,
based on the context, modal users, needs of the highway or road, and jurisdiction.

1430.06(4) Design Vehicle Characteristics

Most transit agencies operate several types of buses within their systems. Vehicle sizes range
from articulated buses to passenger vans operated for specialized transportation purposes and
vanpooling. Several bus types are listed below. (See Chapter 1103, Design Controls, and Chapter
1300 for design vehicle guidance.)

1430.06(4)(a) City Buses (CITY-BUS)

These traditional urban transit vehicles are typically 40 feet long and have a wheelbase of
approximately 25 feet. Many of these vehicles are equipped with either front or rear door
wheelchair lifts or a front “kneeling” feature that reduces the step height for mobility-impaired
patrons. Installing higher curb can reduce the time it takes to kneel a bus and thus increase
reliability.

1430.06(4)(b) Articulated Buses (A-BUS)

Because articulated buses are hinged between two sections, these vehicles can turn within a
relatively short radius. Articulated buses are typically 60 feet in length, with a wheelbase of
22 feet from the front axle to the mid axle and 19 feet from the mid axle to the rear axle. If
articulated buses are the common bus using a stop, adjust the length of the pullout accordingly
to avoid conflicts.

1430.06(4)(c) Small Buses

Some transit agencies operate small buses, which are designed for use in low-volume situations
or for driving on lower-class roads. Small buses are also used for transportation of elderly and
disabled persons and for shuttle services. Passenger vans are a type of small bus used for
specialized transportation and vanpooling. Since the vehicle specifications vary so widely within
this category, consult the local transit authority for the specifications of the particular vehicle in
question.

1430.06(5) Intersection Radii

A fundamental characteristic of transit-accessible development is convenient access and
circulation for transit vehicles. It is important that radii at intersections be designed to
accommodate turning buses. Radii that accommodate turning buses reduce conflicts between
automobiles and buses, reduce bus travel time, and provide maximum comfort for the
passengers.

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Refer to Chapters 1300 and 1310 for intersection design guidance, and take the following factors
into consideration in designing intersection radii:
• Right of way availability
• Angle of intersection
• Width and number of lanes on the intersecting streets
• Feasibility of channelization adjustments such as set-back stop bar or adjusted center
line
• Design vehicle turning radius
• On-street parking and/or curb extensions (see Chapter 1510)
• Allowable bus encroachment
• Operating speed and speed reductions
• Adequate intersection sight distance
• Needs of pedestrians, bicyclists, and other design users (see chapters in the 1100 series
(Division 11) for contextual discussions and Chapter 1230 for roadway types.)

Because of space limitations and generally lower operating speeds in urban areas, curve radii for
turning movements are typically smaller than those used in rural areas.

1430.07 Documentation
Refer to Chapter 300 for design documentation requirements.

1430.08 References
1430.08(1) Federal/State Laws and Codes
Americans with Disabilities Act of 1990 (ADA) (28 Code of Federal Regulations [CFR] Part 36,
Appendix A, as revised July 1, 1994)

Revised Code of Washington (RCW) 46.61.581, Parking spaces for persons with disabilities –
Indication, access – Failure, penalty

RCW 70.92.120, Handicap symbol – Display – Signs showing location of entrance for
handicapped

Washington Administrative Code (WAC) Chapter 468-46, Transit vehicle stop zones

WAC 468-510-010, High occupancy vehicles (HOVs)

1430.08(2) Design Guidance

ADA Field Guide for Accessible Public Rights of Way, WSDOT
 www.wsdot.wa.gov/publications/manuals/fulltext/m0000/ada_field_guide.pdf

ADA Standards for Accessible Design, U.S. Department of Justice (USDOJ), 2010; consists of 28
CFR parts 35 & 36 and the ADA and Architectural Barriers Act (ABA) Accessibility Guidelines for
Buildings and Facilities (ADA-ABAAG; also referred to as the 2004 ADAAG), July 23, 2004, U.S.

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Access Board. (For buildings and on-site facilities; applies to new construction or alterations as
of March 15, 2012.)
 www.access-board.gov/guidelines-and-standards

ADA Standards for Transportation Facilities, USDOT, 2006; consists of 49 CFR Parts 37 & 38 and
the ADA and ABA Accessibility Guidelines for Buildings and Facilities (ADA-ABAAG; also referred
to as the 2004 ADAAG), July 23, 2004, U.S. Access Board as modified by USDOT. (For transit, light
rail, and similar public transportation facilities.)
 www.access-board.gov/guidelines-and-standards

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)

Plans Preparation Manual, M 22-31, WSDOT

Roadside Manual, M 25-30, WSDOT

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

Traffic Manual, M 51-02, WSDOT

Revised Draft Guidelines for Accessible Public Rights-of-Way (PROWAG), November 23, 2005,
U.S. Access Board. The current best practices for evaluation and design of pedestrian facilities
in the public right of way per the following FHWA memoranda:
 http://www.fhwa.dot.gov/environment/bikeped/prwaa.htm
 http://www.fhwa.dot.gov/civilrights/memos/ada_memo_clarificationa.htm
 www.access-board.gov/guidelines-and-standards

Transit Capacity and Quality of Service Manual, Third Edition (TCRP Report 165), Transportation
Research Board.
http://www.trb.org/Main/Blurbs/169437.aspx

1430.08(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, current edition

ADA Standards for Accessible Design, U.S. Department of Justice

 www.ada.gov/stdspdf.htm

Bus Use of Highways: Planning and Design Guidelines, National Cooperative Highway Research
Program Report 155, Transportation Research Board, 1975

Guide for Geometric Design of Transit Facilities on Highways and Streets, AASHTO, 2014
The AASHTO Guide provides a comprehensive reference of current practice in the geometric
design of transit facilities on streets and highways.

Guidelines for the Location and Design of Bus Stops, Transit Cooperative Research Program
(TCRP) Report 19, Transportation Research Board, 1996

Understanding Flexibility in Transportation Design – Washington, WSDOT, 2005

 www.wsdot.wa.gov/research/reports/600/638.1.htm

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1510.01 General 1510.10 Crosswalks
1510.02 References 1510.11 Raised Medians/Traffic Islands
1510.03 Definitions 1510.12 Pedestrian Pushbuttons
1510.04 Policy 1510.13 At-Grade Railroad Crossings
1510.05 ADA Requirements by 1510.14 Pedestrian Grade Separations
Project Type (Structures)
1510.06 Pedestrian Circulation Paths 1510.15 Other Pedestrian Facilities
1510.07 Pedestrian Access Routes (PARs) 1510.16 Illumination and Signing
1510.08 Sidewalks 1510.17 Work Zone Pedestrian Accommodation
1510.09 Curb Ramps 1510.18 Documentation

1510.01 General
Pedestrian travel is a vital transportation mode. It is used at some point by nearly everyone and
is a critical link to everyday life for many. Designers must be aware of the various physical needs
and abilities of pedestrians in order to ensure facilities provide universal access.
Section 504 of the Rehabilitation Act and the Americans with Disabilities Act of 1990 (ADA)
require pedestrian facilities to be designed and constructed so they are readily accessible to and
usable by persons with disabilities. This chapter provides accessibility criteria for the design of
pedestrian facilities that meet applicable state and federal standards.
The pedestrian facilities included in a project are determined during the planning phase based on:
access control of the highway; local transportation plans; comprehensive plans and other plans
(such as Walk Route Plans developed by schools and school districts); the roadside environment;
pedestrian volumes; user age group(s); and the continuity of local walkways along or across the
roadway.
When developing pedestrian facilities within a limited amount of right of way, designers can
be faced with multiple challenges. It is important that designers become familiar with the ADA
accessibility criteria in order to appropriately balance intersection design with the often
competing needs of pedestrians and other roadway users.
Similar to the roadway infrastructure, pedestrian facilities (and elements) require periodic
maintenance in order to prolong the life of the facility and provide continued usability. Title II
of the ADA requires that all necessary features be accessible and maintained in operable working
condition for use by individuals with disabilities.

1510.02 References
1510.02(1) Federal/State Laws and Codes
ADA – 28 Code of Federal Regulations (CFR) Part 35, as revised September 15, 2010
23 CFR Part 652, Pedestrians and Bicycle Accommodations and Projects
49 CFR Part 27, Nondiscrimination on the Basis of Disability in Programs or Activities
Receiving Federal Financial Assistance (Section 504 of the Rehabilitation Act of 1973
implementing regulations)

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Revised Code of Washington (RCW) 35.68, Sidewalks, gutters, curbs and driveways –
All cities and towns
RCW 35.68.075, Curb ramps for persons with disabilities – Required – Standards and
Requirements
RCW 46.04.160, Crosswalk (definition)
RCW 46.61, Rules of the Road
RCW 47.24.020, City streets as part of state highways – Jurisdiction, control

1510.02(2) Design Guidance

ADA Standards for Accessible Design, U.S. Department of Justice (USDOJ), 2010; consists of 28
CFR parts 35 & 36 and the ADA and Architectural Barriers Act (ABA) Accessibility Guidelines
for Buildings and Facilities (ADA-ABAAG; also referred to as the 2004 ADAAG), July 23,
2004, U.S. Access Board as modified by USDOT for entities receiving USDOT funding per 49
CFR Part 27. (Applies to new construction or alterations as of November 29, 2006 for entities
receiving USDOT funding per 49 CFR Part 27.)  https://www.access-board.gov/guidelines-
and-standards/transportation/facilities/ada-standards-for-transportation-facilities
ADA Standards for Transportation Facilities, USDOT, 2006; consists of 49 CFR Parts 37, 38, &
39, the ADA Accessibility Guidelines for Transportation Vehicles, September 6, 1991, and the
ADA and ABA Accessibility Guidelines for Buildings and Facilities (ADA-ABAAG; also referred
to as the 2004 ADAAG), July 23, 2004, U.S. Access Board as modified by USDOT. (For transit,
light rail, and similar public transportation facilities under Federal Transit Administration
jurisdiction.)
 https://www.access-board.gov/guidelines-and-standards/transportation/facilities/ada-standards-
for-transportation-facilities
 https://www.access-board.gov/guidelines-and-standards/transportation/vehicles/adaag-for-
transportation-vehicles
Department of Justice/Department of Transportation Joint Technical Assistance on the Title II of
the Americans with Disabilities Act Requirements to Provide Curb Ramps when Streets, Roads,
or Highways are Altered through Resurfacing, USDOJ and USDOT, July 2013
 http://www.ada.gov/doj-fhwa-ta.htm
 http://www.ada.gov/doj-fhwa-ta-glossary.htm
 https://www.ada.gov/doj-fhwa-ta-supplement-2015.html
Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as
adopted and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices
for streets and highways” (MUTCD)  www.wsdot.wa.gov/publications/manuals/mutcd.htm
Revised Draft Guidelines for Accessible Public Rights-of-Way (PROWAG), November 23, 2005,
U.S. Access Board. The current best practices for evaluation and design of pedestrian facilities
in the public right of way per the following FHWA Memoranda:
 https://www.fhwa.dot.gov/environment/bicycle_pedestrian/resources/prwaa.cfm
 http://www.fhwa.dot.gov/civilrights/memos/ada_memo_clarificationa.htm
 https://www.access-board.gov/guidelines-and-standards/streets-sidewalks/public-rights-of-
way/background/revised-draft-guidelines
Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01,
WSDOT  www.wsdot.wa.gov/publications/manuals/m21-01.htm

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1510.02(3) Supporting Information

1991 ADA Standards for Accessible Design, USDOJ; consists of 28 CFR parts 35 & 36 and the
ADA Accessibility Guidelines for Buildings and Facilities (ADAAG), July 1991, U.S. Access
Board. (For buildings and on-site facilities: Expired for new construction and alterations. To
be used only for evaluating the adequacy of new construction or alteration that occurred prior
to November 29, 2006 for entities receiving USDOT funding per 49 CFR Part 27.)
 https://www.access-board.gov/guidelines-and-standards/buildings-and-sites/about-the-ada-
standards/background/adaag
A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, Current
version adopted by FHWA
Field Guide for Accessible Public Rights of Way, WSDOT, November 1, 2012
 http://www.wsdot.wa.gov/publications/fulltext/roadside/ada_field_guide.pdf
Guide for the Planning, Design, and Operation of Pedestrian Facilities, AASHTO, 2004. Provides
guidance on the planning, design, and operation of pedestrian facilities along streets and highways.
Specifically, the guide focuses on identifying effective measures for accommodating pedestrians
on public rights of way. It can be purchased through the AASHTO website.
Highway Capacity Manual, Transportation Research Board (TRB), 2000
Pedestrian Facilities Guidebook: Incorporating Pedestrians Into Washington’s Transportation
System, OTAK, 1997  www.wsdot.wa.gov/publications/manuals/fulltext/m0000/pedfacgb.pdf
Pedestrian Facilities Users Guide – Providing Safety and Mobility, FHWA, 2002. Provides
useful information regarding walkable environments, pedestrian crashes and their
countermeasures, and engineering improvements for pedestrians.
 https://www.fhwa.dot.gov/publications/research/safety/01102/01102.pdf
Proposed Accessibility Guidelines for Pedestrian Facilities in the Public Right-of-Way, July 26,
2011, U.S. Access Board. Federal Notice of Proposed Rule Making that gives a preview of
potential future revisions to the PROWAG.  https://www.access-board.gov/guidelines-and-
standards/streets-sidewalks/public-rights-of-way/proposed-rights-of-way-guidelines
“Special Report: Accessible Public Rights-of-Way – Planning & Design for Alterations,” Public
Rights-of-Way Access Advisory Committee, July 2007
 https://www.access-board.gov/attachments/article/756/guide.pdf
Understanding Flexibility in Transportation Design – Washington, WSDOT, 2005
 www.wsdot.wa.gov/research/reports/600/638.1.htm
Washington State Bicycle Facilities and Pedestrian Walkways Plan
 www.wsdot.wa.gov/bike/bike_plan.htm
Terminal Design Manual, Chapter 300 Accessibility, WSDOT, Washington State
Ferries Division  www.wsdot.wa.gov/publications/manuals/m3082.htm

1510.03 Definitions
Refer to the Design Manual Glossary for definitions of many of the terms used in this chapter.

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1510.04 Policy
1510.04(1) General
It is WSDOT policy to provide appropriate pedestrian facilities along and across sections of state
routes as an integral part of the transportation system. Federal Highway Administration (FHWA)
and WSDOT policy is that bicycle and pedestrian facilities be given full consideration in the
planning and design of new construction and reconstruction highway projects, except where
bicycle and pedestrian use is prohibited.

1510.04(2) Jurisdiction
Proposed projects in public rights of way must address ADA compliance as described in this
chapter. (See 1510.05 for ADA requirements by project type.) Regardless of which public
agency has jurisdiction within the right of way, the public agency that is sponsoring the
project is responsible for ensuring ADA compliance is addressed on its project.
On all state routes outside of incorporated cities and on those with limited access (full, partial,
and modified) within incorporated cities, jurisdiction remains with the state unless modified
by a maintenance agreement. In turnback areas where the turnback agreement has not been
completed, the state maintains full jurisdiction (see Chapters 510, 520, and 530).
When project work occurs on a managed access state route inside an incorporated city that has
jurisdiction beyond the curbs (RCW 47.24.020), design pedestrian facilities using the city design
standards adopted in accordance with RCW 35.78.030 and the most current ADA requirements.
Document the coordination with the city in the Design Documentation Package (DDP). Refer
to Chapter 300 for information about the DDP.

1510.04(3) Transition Planning

Section 504 of the Rehabilitation Act and the ADA require all public entities to conduct a self-
evaluation of their programs and activities, including sidewalks, curb ramps, and other pedestrian
facilities and elements within the public right of way, to determine if barriers exist that prevent
people with disabilities from being able to access these programs and activities.
If barriers are identified, agencies with 50 or more employees must develop and implement
a transition plan that describes the barriers, the modifications needed, and a schedule for
when the needed work will be accomplished.

1510.04(4) Maintenance
As noted in 1510.01, Title II of the ADA requires that a public entity maintain in operable
working condition those features of facilities and equipment that are required to be readily
accessible to and usable by persons with disabilities.

1510.05 ADA Requirements by Project Type

Wherever pedestrian facilities are intended to be a part of the transportation facility, federal
regulations (28 CFR Part 35) require that those pedestrian facilities meet ADA guidelines.
All new construction or alteration of existing transportation facilities must be designed and
constructed to be accessible to and usable by persons with disabilities. FHWA is one of the
federal agencies designated by the Department of Justice to ensure compliance with the
ADA for transportation projects.

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1510.05(1) New Construction Projects

New construction projects address the construction of a new roadway, interchange, or other
transportation facility where none existed before. For these projects, pedestrians’ needs are
assessed and included in the project. All pedestrian facilities included in these projects must
fully meet the accessibility criteria when built.

1510.05(2) Alteration Projects

Any project that affects or could affect the usability of a pedestrian facility is classified as an
alteration project. Alteration projects include, but are not limited to, renovation; rehabilitation;
reconstruction; historic restoration; resurfacing of circulation paths or vehicular ways; and
changes or rearrangement of structural parts or elements of a facility. Where existing elements
or spaces are altered, each altered element or space within the limits of the project shall comply
with the applicable accessibility requirements to the maximum extent feasible.
The following are some examples of project types that are classified as alteration projects and
can potentially trigger a variety of ADA requirements:
• HMA overlay or inlay
• Traffic signal installation or retrofit
• Roadway widening
• Realignment of a roadway (vertical or horizontal)
• Sidewalk improvements
• PCCP panel repair/replacement
• Bridge replacement
• Raised channelization
The following are not considered alterations:
• Spot pavement repair
• Liquid-asphalt sealing, chip seal (BST), or crack sealing
• Lane restriping that does not alter the usability of the shoulder
If there is uncertainty as to whether a project meets the definition of an alteration project, consult
with the Regional ADA Liaison.
The following apply to alteration projects:
• All new pedestrian facilities included in an alteration project that are put in place within
an existing developed right of way must meet applicable accessibility requirements to the
maximum extent feasible.
• All existing pedestrian facilities disturbed by construction of an alteration project must
be replaced. The replacement facilities must meet applicable accessibility requirements
to the maximum extent feasible.
• An alteration project shall not decrease or have the effect of decreasing the accessibility
of a pedestrian facility or an accessible connection to an adjacent building or site below
the ADA accessibility requirements in effect at the time of the alteration.
• Within the construction impact zone of an alteration project, any existing connection from
a pedestrian access route to a crosswalk (marked or unmarked) that is missing a required
curb ramp must have a curb ramp installed that meets applicable accessibility requirements
to the maximum extent feasible. (See 1510.09(2) for curb ramp accessibility criteria.)

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Pedestrian Facilities Chapter 1510

• A crosswalk served by a curb ramp must also have an existing curb ramp in place
on the receiving end unless there is no curb or sidewalk on that end of the crosswalk
(RCW 35.68.075). If there is no existing curb ramp in place on the receiving end, an
accessible curb ramp must be provided. This requirement must be met regardless of
whether the receiving end of the crosswalk is located within the project’s limits.
• Within the construction impact zone of an alteration project, evaluate all existing curb
ramps to determine whether curb ramp design elements meet the accessibility criteria. (See
1510.09(2) for curb ramp accessibility criteria.) Modify existing curb ramps that do not meet
the accessibility criteria to meet applicable accessibility requirements to the maximum
extent feasible. This may also trigger modification of other adjacent pedestrian facilities
to incorporate transitional segments in order to ensure specific elements of a curb ramp
will meet the accessibility criteria.
• Within the construction impact zone of an alteration project that includes hot mix asphalt
overlay (or inlay) of an existing roadway and does not include reconstruction, realignment,
or widening of the roadway, evaluate all existing marked and unmarked crosswalks. (See
1510.10(2) for crosswalk accessibility criteria.) If it is not possible to meet the applicable
accessibility requirements for crosswalks, document this in the DDP.
• Within the construction impact zone of an alteration project that includes reconstruction,
realignment, or widening of the roadway, evaluate all existing crosswalks (marked or
unmarked) to determine whether crosswalk design elements meet the accessibility criteria.
(See 1510.10(2) for crosswalk accessibility criteria.) Modify crosswalk slopes to meet the
applicable accessibility requirements to the maximum extent feasible.
It may not always be possible to fully meet the applicable accessibility requirements during
alterations of existing facilities. If such a situation is encountered, consult with the Regional
ADA Liaison to develop a workable solution to meet the accessibility requirements to the
maximum extent feasible. Cost is not to be used as a justification for not meeting the accessibility
criteria. Physical terrain or site conditions that would require structural impacts, environmental
impacts, or unacceptable impacts to the community in order to achieve full compliance with the
accessibility criteria are some of the factors that can be used to determine that the maximum
extent feasible is achieved. If it is determined to be virtually impossible to meet the accessibility
criteria for an element, document the decision in one of the following ways, as applicable:
• Within the construction impact zone of an alteration project that does not include
reconstruction, realignment, or widening of the roadway, document the following deficient
elements in the DDP:
o Perpendicular curb ramp or parallel curb ramp landing cross slope that is constrained
by the existing roadway gutter profile and exceeds 2%, but is less than or equal to 5%,
that cannot be constructed to fully meet applicable accessibility requirements.
o Flared side of a perpendicular curb ramp that is constrained by the existing roadway
gutter profile and has a slope that exceeds 10%, but is less than or equal to 16.7%,
that cannot be constructed to fully meet applicable accessibility requirements.
o For any deficient element that does not match the preceding description, document the
decision via a stamped and signed Maximum Extent Feasible (MEF) document. The MEF
document will be reviewed by the appropriate Assistant State Design Engineer (ASDE)
and the Headquarters (HQ) ADA Compliance Manager. If acceptable, the MEF document
will be approved and included in the DDP.

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1510.05(2)(a) Requirements for Crossings with Pedestrian Pushbuttons

Coordinate sidewalk and curb ramp work with signal system work so that signal poles with
pedestrian equipment meet accessibility requirements for APS pushbuttons to the maximum
extent feasible. See 1510.12 for additional information on pedestrian pushbutton accessibility.
For existing signal systems only, the work required for each signal system location is determined
as follows:
1. If no sidewalk ramp work is being performed at a signal system location, no work is
required for that signal system as part of the project.
2. If any ramp is being reconstructed at a signal system location, and the traffic signal
system is owned by WSDOT, then all poles with pedestrian equipment shall be made
accessible for the entire traffic signal system at that location. This may require new or
relocated poles, as well as additional ramp and sidewalk work beyond that previously
described in 1510.05(2).
3. If any ramp is being reconstructed at a signal system location, and the traffic signal
system is owned by another agency, only poles with pedestrian pushbuttons serving a
crossing served by a ramp that is being reconstructed are required to be made accessible
as part of the project. This may require reconstruction of the ramps, landings, or sidewalk
areas at both ends of the crossing. The remaining crossings and poles may be addressed if
the owning agency wishes to provide funding for the additional work.
If APS pushbuttons are not being installed as part of a project, any revised pole locations shall be
designed to meet accessibility requirements with a conventional pushbutton installed and with an
APS pushbutton installed, so that the pole does not have to be relocated when the conventional
pushbutton is replaced with an APS pushbutton. Typically a location that is accessible with an
APS pushbutton installed will be accessible with a conventional pushbutton installed, but
verification is required.
Locations where these requirements cannot be fully met shall follow the procedures for maximum
extent feasible documentation as previously described.

1510.06 Pedestrian Circulation Paths (PCP)

PCP are prepared exterior or interior ways of passage provided for pedestrian travel. They include
independent walkways, sidewalks, shared-use paths, and other types of pedestrian facilities.
Pedestrian circulation paths can either be immediately adjacent to streets and highways or
separated from them by a buffer. Examples of PCP are shown in Exhibit 1510-1.
When the PCP is located behind guardrail, address protruding bolts. Installing a rub rail or a “W-
beam” guardrail on the pedestrian side of the posts can mitigate potential snagging and also serve
as a guide for sight-impaired pedestrians.
Provide a smooth finish to vertical surfaces adjacent to a PCP to mitigate potential snagging or
abrasive injuries from accidental contact with the surface. Where adjacent walkway segments
diverge, such as can occur if a parallel curb ramp does not occupy the entire width of a PCP, any
resulting drop-offs must be protected to prevent trips or falls.
When relocation of utility poles and other fixtures is necessary for a project, determine the impact
of their new location on all PCP. Look for opportunities to relocate obstructions, such as existing
utility objects, away from the PCP.

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Pedestrian Circulation Paths

Exhibit 1510-1

Highway shoulders are an extension of the roadway and are not typically considered pedestrian
facilities. Pedestrians are allowed to use many state highways. Although pedestrians are allowed
to travel along the shoulder in these cases, its main purpose is to provide an area for disabled
vehicles, a recovery area for errant vehicles, and positive drainage away from the roadway.
Shoulders may serve as a pedestrian facility when sidewalks are not provided. If pedestrian
generators, such as bus stops, are present and pedestrian usage is evident, a 4-foot-wide
paved shoulder is adequate. Note that detectable warning surfaces should not be installed
where a sidewalk ends and pedestrians are routed onto a shoulder since the shoulder is not
a vehicular traveled way.
Where pedestrian traffic is evident, consider a separate PCP during the planning and
programming of the project. Consult with the State Bicycle and Pedestrian Coordinator.

1510.06(1) Accessibility Criteria for Pedestrian Circulation Paths

The following criteria apply across the entire width of the PCP, not just within the pedestrian
access route.

1510.06(1)(a) Vertical Clearance

• The minimum vertical clearance for objects that protrude into or overhang a pedestrian
circulation path is 80 inches.
• If the minimum vertical clearance cannot be provided, railings or other barriers shall be
provided. The leading bottom edge of the railing or barrier shall be located 27 inches
maximum above the finished surface for cane detection.
Note: Per the MUTCD, the vertical clearance to the bottom of signs is 7 feet (84 inches.)

1510.06(1)(b) Horizontal Encroachment

• Protruding objects on PCPs shall not reduce the clear width of the pedestrian access route to
less than 4 feet, exclusive of the curb.
Note: If an object must protrude farther than 4 inches into a PCP at a height that is greater
than 27 inches and less than 80 inches above the finished surface, then it must be equipped
with a warning device that is detectable by a vision-impaired person who navigates with a
cane. The minimum clear width of the PAR must still be provided.

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1510.06(1)(c) Post-Mounted Objects

• Objects mounted on posts, at a height that is greater than 27 inches and less than 80 inches
above the finished surface, shall not protrude more than 4 inches into a pedestrian circulation
path.
Note: If an object must protrude farther than 4 inches into a pedestrian circulation path at
a height that is greater than 27 inches and less than 80 inches above the finished surface,
then it must be equipped with a warning device that is detectable by a vision-impaired
person who navigates with a cane. The minimum clear width of the pedestrian access
route must still be provided.
• Where a sign or other obstruction on a pedestrian circulation path is mounted on multiple
posts, and the clear distance between the posts is greater than 12 inches, the lowest edge
of the sign or obstruction shall be either 27 inches maximum or 80 inches minimum
above the finished surface.

1510.07 Pedestrian Access Routes (PARs)

All PCPs are required to contain a continuous PAR (see Exhibit 1510-2) that connects to all
adjacent pedestrian facilities, elements, and spaces that are required to be accessible. PARs
consist of one or more of the following pedestrian facilities: walkways/sidewalks, crosswalks,
curb ramps (excluding flares), landings, pedestrian overpasses/underpasses, access ramps,
elevators, and platform lifts.

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Pedestrian Circulation Path (PCP)

Pedestrian Access Route (PAR)

Continuous Buffer
(Planting Strip)

With Continuous Buffer

Pedestrian Circulation Path (PCP)

Pedestrian Access Route (PAR)

Tree in sidewalk with or without tree grate

Without Continuous Buffer

Relationship Between Pedestrian Circulation Paths and Pedestrian Access Routes

Exhibit 1510-2

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1510.07(1) Accessibility Criteria for Pedestrian Access Routes

1510.07(1)(a) Clear Width
• The minimum continuous and unobstructed clear width of a PAR shall be 4 feet, exclusive of
the width of the curb.
• PARs that are less than 5 feet in clear width, exclusive of the width of the curb, shall provide
passing spaces at intervals no farther apart than 200 feet. Passing spaces shall be 5 feet wide
minimum, for a minimum distance of 5 feet.

Note: Provide wheel stops or a wider sidewalk to remedy the encroachment into the PAR.

Obstructed Pedestrian Access Route

Exhibit 1510-3

1510.07(1)(b) Cross Slope and Grade

• The cross slope of a PAR shall be 2% maximum.
Note: It is recommended that cross slopes be designed to be less than the allowed maximum
to allow for some tolerance in construction. For example: design for a maximum 1.5% cross
slope (rather than 2% maximum).
Exceptions:
1. Midblock crosswalks – The cross slope of the crosswalk and any connected curb ramp
is permitted to match street or highway grade.
2. Crosswalks without stop sign control – The cross slope of the crosswalk can be up to
5% maximum.
• Where a PAR is contained within the highway right of way, its grade shall not exceed the
general grade established for the adjacent roadway.
Exception: The maximum grade in a crosswalk (marked or unmarked) is 5%, measured
parallel to the direction of pedestrian travel in the crosswalk.
• Where a PAR is not contained within the highway right of way, the maximum running slope
allowed is 5% unless designed as an access ramp. (See 1510.15(2) for access ramp
accessibility criteria.)
• For additional criteria when a PAR is supported by a structure, see 1510.14.

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1510.07(1)(c) Surface
• The surface of the PAR shall be firm, stable, and slip resistant. Use hard surfaces like cement
or asphalt concrete; crushed gravel is not considered to be a stable, firm surface.
• Vertical alignment shall be planar within curb ramps, landings, and gutter areas within the
PAR and within clear spaces for accessible pedestrian signals, street furniture, and operable
parts.
• Grade breaks shall be flush.
• Surface discontinuities (see Exhibits 1510-4 and 1510-5) on existing surfaces in the
pedestrian access route (such as at the joints of settled or upheaved sidewalk panels) may
not exceed ½ inch maximum. Vertical discontinuities between ¼ inch and ½ inch maximum
shall be beveled at 2H:1V or flatter. Apply the bevel across the entire level change.
Exception: No surface discontinuity is allowed at the connection between an existing curb
ramp or landing and the gutter. This grade break must be flush.

2
1/2 inch max. 1
1/4 inch max.

2
1
1/2 inch
max.
1/4 inch max.

Beveling Options
Exhibit 1510-4

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Surface Discontinuities (Noncompliant)

Exhibit 1510-5

• Gratings, access covers, utility objects, and other appurtenances shall not be located on curb
ramps, landings, or gutters within the PAR.
• Locate gratings, access covers, utility objects, and other appurtenances outside the PAR on
walkways and sidewalks. Where this is not possible, ensure covers, grates, and lids are
designed to be slip resistant and are installed flush with the surrounding surface (see the
Standard Plans).
1510.07(1)(d) Horizontal Openings
• Any sidewalk joints or gratings that are in the PAR shall not permit passage of a sphere more
than ½ inch in diameter.
• Elongated openings shall be placed so that the long dimension is perpendicular to the
dominant direction of travel.
• Openings for wheel flanges at pedestrian crossings of nonfreight rail track shall be 2½ inches
maximum (3 inches maximum for freight rail track).
• For additional requirements when a PAR crosses a railroad, see 1510.13.

1510.08 Sidewalks
Sidewalks are one type of PCP. (See 1510.06 for PCP accessibility criteria.) Plan the design of
sidewalks carefully to include a PAR that provides universal access. (See 1510.07 for PAR
accessibility criteria.) Sidewalk design elements are found in Exhibit 1510-7 and details for raised
sidewalks are shown in the Standard Plans. Wherever appropriate, make sidewalks continuous
and provide access to side streets. The most pleasing and comfortable installation for the
pedestrian is a sidewalk separated from the traveled way by a planted buffer. This provides a
greater separation between vehicles and pedestrians than curb alone.

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1510.08(1) Sidewalk and Buffer Widths

The WSDOT minimum sidewalk width is 5 feet (excluding the curb), but providing wider
sidewalks is encouraged. Wider sidewalks are desirable on major arterials, in central business
districts, and along parks, schools, and other major pedestrian generators. When sidewalks abut
storefronts, additional width should be provided to accommodate window-shoppers and to avoid
conflicts with opening doors and pedestrians entering or leaving the buildings.
When a buffer (vegetated as well as alternate pavement) is provided, the buffer should be at
least 3 feet wide (excluding the curb). Document the decision to reduce a buffer width to less
than 3 feet in the DDP.
If trees or shrubs are included in a buffer, coordinate with the region or HQ Landscape Architect.
Take into account Design Clear Zone guidelines (see Chapter 1600). Design subsurface
infrastructure (such as structural soils) and select plants whose root systems do not cause
sidewalks to buckle or heave. Coordinate buffer planting with maintenance personnel.
Where possible, strive to accommodate snow storage while keeping the pedestrian route free of
snow accumulation. Make sure maintenance access is not obstructed. Shoulders, bike lanes, and
on-street parking are not considered buffers, but they do offer the advantage of further separation
between vehicles and pedestrians.

Sidewalks With Buffers

Exhibit 1510-6

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Buffer 5' - 0" min.

>3' - 0" (typ.) Sidewalk
Curb and
gutter 2% max.

Top soil if area is a

planting strip

5' - 0'’ min.

2% max.

5' - 0" min.

4"

2% max.

1' - 0"
Biofiltration area 5' - 0" min

1' - 0" 2% max

min.

Bridge or pedestrian railing

5' - 0" min. Barrier

2% max.

Notes:
If vertical drop is within the Design Clear Zone and the posted speed is > 35 mph, then barrier may be needed
(see Chapter 1600).
If vertical drop is > 2 feet 6 inches and barrier is not needed, then railing is indicated.
If vertical drop is < 2 feet 6 inches and barrier is not needed, then a 4-inch curb at back of sidewalk is adequate.

General:
See the Standard Plans for details on slopes at back of sidewalk.
See Chapter 1230 for slope selection criteria.
Sidewalks may be sloped away from the roadway for stormwater treatment (see the Highway Runoff Manual).

Typical Sidewalk Designs

Exhibit 1510-7

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1510.08(2) Sidewalks at Driveways

Provide a PAR where driveways intersect a PCP (see Exhibit 1510-8). The Standard Plans shows
details of driveway designs that provide a PAR. (See 1510.06 and 1510.07 for accessibility
criteria.) When a driveway is signalized as part of an intersection, contact the Region ADA
Liaison for guidance.

Typical Driveways
Exhibit 1510-8

1510.09 Curb Ramps

Curb ramps provide an accessible connection from a raised sidewalk down to the roadway
surface. A curb ramp, or combination of curb ramps, is required to connect PAR to crosswalks
(marked or unmarked) where curbs and sidewalks are present, except where pedestrian crossing is
prohibited. (See 1510.10(2)(c) for guidance on closed crossings and Exhibit 1510-17 for an
example.)
For new construction projects, provide a curb ramp oriented in each direction of pedestrian travel
within the width of the crosswalk it serves. For alteration projects, a curb ramp oriented in each
direction of pedestrian travel within the width of the crosswalk it serves is desirable.
Every curb ramp must have a curb ramp at the other end of the crosswalk it serves unless there
is no curb or sidewalk on that side (RCW 35.68.075).
Curb ramps are also required at midblock crossings where curbs and sidewalks are present.

1510.09(1) Types of Curb Ramps

Different types of curb ramps can be used: perpendicular, parallel, and combination. Carefully
analyze and take into consideration drainage patterns, especially when designing a parallel or
combination curb ramp installation.

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1510.09(1)(a) Perpendicular Curb Ramp

Perpendicular curb ramps (see Exhibits 1510-9 and 1510-10) are aligned to cut through the curb
and meet the gutter grade break at a right angle. The landing is to be located at the top of the curb
ramp.
1. Advantages

• Having the path of travel aligned to cross the gutter grade break at a right angle facilitates
usage by individuals with mobility devices.
• The height of the ramp run relative to the gutter elevation may facilitate drainage.
• The height of the ramp run relative to the gutter elevation discourages vehicular traffic
from cutting across the corner.
• On small-radius corners, the ramp alignment may be more closely aligned with the
alignment of the crosswalk markings, which facilitates direction finding for the
visually impaired.
2. Disadvantages

• The ramp run and landing might not fit within available right of way.
• On small-radius corners, the flares may not fit between closely spaced perpendicular
curb ramps.
• On larger-radius corners, there will be less facilitation of direction finding for the
visually impaired due to the requirement that the path of travel cross the gutter
grade break at a right angle.

Perpendicular Curb Ramp

Exhibit 1510-9

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Ramp cross slope

Ramp running slope

Level landing
Wi
dth
Fl
a n gth
re Le
mp
Ra
Detectable
warning surface Flar
e

Counter slope
Gutter
Curb

Perpendicular Curb Ramp Common Elements

Exhibit 1510-10

1510.09(1)(b) Parallel Curb Ramp

Parallel curb ramps (see Exhibits 1510-11 and 1510-12) are aligned with their running slope
in line with the direction of sidewalk travel, parallel to the curb. The landing is located at the
bottom of the curb ramp.
1. Advantages
• Requires minimal right of way.
• Allows ramps to be extended to reduce ramp grade within available right of way.
• Provides edges on the side of the ramp that are detectable to vision-impaired pedestrians
who navigate with a cane.
2. Disadvantages

• Depending on the style of parallel curb ramp, pedestrian through traffic on the sidewalk
may need to negotiate two ramp grades instead of one, possibly making it more difficult
to traverse for some.
• The installation of additional drainage features in the upstream gutter line may be
necessary to prevent the accumulation of water or debris in the landing at the bottom
of the ramp.

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Parallel Curb Ramp

Exhibit 1510-11

Ramp cross slope

Ramp running slope

Level landing
p
am

Ramp running slope

R

Ramp cross slope Gutter

p
Ram

Counter slope

Detectable
Curb warning
surface

Note: The pedestrian curb shown on the back of the curb ramp is intended to retain material in a cut
section and is not required if there is no material to retain due to the nature of the roadside topography.

Parallel Curb Ramp Common Elements

Exhibit 1510-12

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1510.09(1)(c) Combination Curb Ramp

Combination curb ramps (see Exhibit 1510-13) combine the use of perpendicular and parallel
types of curb ramps. Landings may be shared by multiple ramps in this application. Buffer areas
and pedestrian curbing that define the pedestrian path of travel are inherent design elements for
this type of curb ramp.
1. Advantages
• Allows the elevation difference between the sidewalk and the gutter line to be
transitioned with multiple ramps. This can help achieve compliant ramp running slopes.
• Provides additional locations in the gutter line along the radius where drainage structures
can be placed outside the pedestrian access route due to the well-defined pedestrian paths
of travel.
• Can be constructed within available right of way when the right of way boundary
is located at the back of the existing sidewalk, provided sufficient buffer width is
available on the roadway side of the sidewalk.
• Provides a way to avoid the relocation of existing features such as utility poles, fire
hydrants, and signal poles by incorporating those features into the buffer areas.
• The pedestrian curbing that defines the buffer areas and forms the curb returns for
the perpendicular ramp connections facilitates direction finding for a vision-impaired
person who navigates with a cane.
2. Disadvantages

• Has a higher construction cost than other curb ramp types due to extensive use
of curbing and a larger footprint.
• Due to generally flatter ramp grades and multi-tiered ramp elements, inadequate
drainage and accumulation of debris can occur.

Combination Curb Ramps

Exhibit 1510-13

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1510.09(2) Accessibility Criteria for Curb Ramps

The accessibility criteria for PCPs and PARs described in 1510.06 and 1510.07 also apply to curb
ramps, except where superseded by the following additional accessibility criteria specifically for
curb ramps.

1510.09(2)(a) Clear Width

• The clear width of curb ramps and their landings shall be 4 feet minimum, excluding flares.

1510.09(2)(b) Running Slope

• The running slope of curb ramps shall not exceed 8.3% maximum.
Note: It is recommended that running slopes be designed to be less than the allowed
maximum to allow for some tolerance in construction. For example, design for a
maximum 7.5% curb ramp running slope (rather than the 8.3% maximum).
• The running slope of a perpendicular curb ramp shall intersect the gutter grade break
at a right angle at the back of curb.
• If the maximum running slope of 8.3% cannot be achieved due to existing physical
constraints, the ramp shall be as flat as possible but the ramp length is not required to
exceed 15 feet.

1510.09(2)(c) Cross Slope

• The cross slope of curb ramp shall not be greater than 2%, measured perpendicular to the
direction of travel.
Note: It is recommended that cross slopes be designed to be less than the allowed maximum
to allow for some tolerance in construction. For example, design for a maximum 1.5% cross
slope (rather than the 2% maximum).
Exception: The cross slopes of curb ramps at midblock crossings are permitted to match the
street or highway grade.

1510.09(2)(d) Landing
A level landing is required either at the top of a perpendicular ramp or the bottom of a parallel
curb ramp, as noted in 1510.09(1)(a) and (b) for the type of curb ramp used.
• Provide a landing that is at least 4 feet minimum length by 4 feet minimum width.
• The running and cross slopes of a curb ramp landing shall be 2% maximum.
Note: It is recommended that cross slopes be designed to be less than the allowed maximum
to allow for some tolerance in construction. For example, design for a maximum 1.5% cross
slope (rather than 2% maximum).
Exception: The running and cross slopes of landings for curb ramps at midblock crossings
are permitted to match the street or highway grade.

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1510.09(2)(e) Flares
• Flared sides are to be used only where a PCP crosses the curb ramp from the side.
• Flared sides are to have a slope of 10% maximum, measured parallel to the back of curb.
1510.09(2)(f) Counter Slope
• The counter slope of the gutter or street at the foot of a curb ramp or landing shall be 5%
maximum.
1510.09(2)(g) Detectable Warning Surfaces
• Detectable warning surfaces are required where curb ramps or landings connect to
a roadway. (See the Standard Plans for placement details and other applications.)
• Detectable warning surfaces shall contrast visually (either light-on-dark or dark-on-light)
with the adjacent walkway surface, gutter, street, or highway.
Note: Federal yellow is the color used to achieve visual contrast on WSDOT projects.
Within cities, other contrasting colors may be used if requested by the city.

1510.09(2)(h) Surfaces
• Surfaces of curb ramps shall be firm, stable, and slip resistant.
• Gratings, access covers, utility objects, and other appurtenances shall not be located
on curb ramps, landings, or gutters within the pedestrian access route.

1510.09(2)(i) Grade Breaks

• Vertical alignment shall be planar within curb ramp runs, landings, and gutter areas
within the PAR.
• Grade breaks at the top and bottom of curb ramps shall be perpendicular to the direction
of travel on the ramp run.
• Surface slopes that meet at grade breaks shall be flush.
1510.09(2)(j) Clear Space
• Beyond the curb face where the bottom of a curb ramp or landing meets the gutter,
a clear space of 4 feet minimum by 4 feet minimum shall be provided in the roadway
that is contained within the width of the crosswalk and located wholly outside the
parallel vehicle travel lane.
Note: Clear space is easily achieved when a separate curb ramp is provided, oriented
in each direction of pedestrian travel within the width of the crosswalk it serves.

1510.09(3) Curb Ramp Drainage

Surface water runoff from the roadway can flood the lower end of a curb ramp. Provide catch
basins or inlets to prevent ponding at the base of curb ramps and landings. Exhibit 1510-14
shows examples of drainage structure locations. Verify that drainage structures will not be
located in the PAR.

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Flow direction of
surface runoff

Curb ramps Drainage feature

(catch basin or inlet)

If ponding could occur,

consider additional
catch basins or inlets

Drainage feature
Flow direction of
(catch basin or inlet)
surface runoff

Curb ramps

Typical Curb Ramp Drainage

Exhibit 1510-14

1510.10 Crosswalks
1510.10(1) Designing Crossing Facilities
Evaluate the following for crossing facilities to address the needs of all user modes:
• Minimize turning radii to keep speeds low. (See Chapter 1300 for design vehicle guidance.)
• Place crosswalks so they are visible and connect to the adjacent pedestrian facilities.
• Provide sight distance (driver to pedestrian; pedestrian to driver).
• Use a separate left-turn phase along with a “WALK/DON’T WALK” signal.
• Restrict or prohibit turns.
• Shorten crossing distance.
• Use a raised median/cut-through island for a pedestrian refuge.
• Use accessible pedestrian signals (APS).
• Use signing and delineation as determined by the region Traffic Engineer.
• Place crosswalks as close as practicable to the intersection traveled way.
• Provide pedestrian-level lighting.
• Consider the crosswalk location in relation to transit stops.
• Provide a PAR that meets the accessibility criteria at all pedestrian crossings.

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1510.10(2) Crosswalks at Intersections

Provide a PAR within marked and unmarked pedestrian crossings. (See 1510.07 for accessibility
criteria for PAR.)
Crosswalks are provided on all legs of an intersection, except in rare cases. There are normally
three crosswalks at a “T” intersection and four crosswalks at a “four-leg” intersection. For
pedestrian route continuity, the minimum number of crosswalks is two at “T” intersections
and three at “four-leg” intersections. One example where crosswalks might not be provided on
all interaction legs is a diamond interchange with heavy left-turn movements from the off-ramp
approach. (See 1510.10(2)(c) for Closed Crossings policy.)

The Traffic Manual provides recommendations for determining pedestrian markings based on lane
configuration, vehicular traffic volume, and speed. However, coordinate with the region Traffic
Engineer early on with any existing or proposed crosswalks. The Traffic Engineer makes the final
determination on appropriate signing and delineation.

1510.10(2)(a) Unmarked Crossings

Legal crosswalks exist at all intersections, whether marked or not, regardless of the number
of legs at the intersection. An unmarked crosswalk (see Exhibit 1510-15) is the portion of the
roadway behind a prolongation of the curb or edge of the through traffic lane and a prolongation
of the farthest sidewalk connection or, in the event there are no sidewalks, between the edge of
the through traffic lane and a line 10 feet from there (RCW 46.04.160).

Unmarked
crosswalk
areas 10 FEET

SHOULDER
SHOULDER

VARIES VARIES
(To back of curb ramp (To back of curb ramp
connection to street) connection to street)

SIDEWALK SIDEWALK

VARIES
(To back of curb ramp
connection to street)

Unmarked Crosswalks
Exhibit 1510-15

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1510.10(2)(b) Marked Crossings

Marked crosswalks are used at intersections or midblock crossings. They should not to be used
indiscriminately, but considered based on a thorough evaluation of site conditions. Maintenance
agreements and RCW 47.24.020 provide jurisdictional authority for decisions to mark crosswalks
based on a population threshold of 27,500 and should be consulted prior to a decision to mark a
crosswalk. Consult region Traffic Offices for “best practices” for marking crosswalks based on
intersection type. The MUTCD, the AASHTO Guide for the Planning, Design, and Operation of
Pedestrian Facilities, and the NACTO Urban Street Design Guide are all good resources to use
when evaluating locations for marked crosswalks.
The desirable width for a marked crosswalk is 10 feet (6 feet minimum, with justification). The
preferred type of marked crosswalk is a longitudinal pattern known as a Ladder Bar, which is
shown in the Standard Plans and Exhibit 1510-16. Stop and yield line dimensions and placement
must conform to the MUTCD and are shown in the Standard Plans.
Some decorative crosswalk materials (such as colored pavement or bricks) may cause confusion
for visually impaired pedestrians and can create discomfort for wheelchair users. Supplement
decorative crosswalks with pavement markings to enhance visibility and delineate the crosswalk.
Refer to the MUTCD and the Local Agency Crosswalk Options website:
 www.wsdot.wa.gov/design/standards/plansheet/pm-2.htm

Marked crosswalks

Refuge Island

Curb ramp

Marked crosswalks

Marked Pedestrian Crossing

Exhibit 1510-16

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1510.10(2)(c) Closed Crossings

Pedestrian crossings shall only be closed for documented potential or observed crash concerns or
for essential signal operations. If a crossing has been previously closed as indicated by existing
signing and ADA facilities are being evaluated, provide an appropriate treatment that is
detectable by people with vision difficulties who navigate with a cane, such as directional
pedestrian curbing and removal of ramps at these closed crossing. The region Traffic Engineer
is the approval authority for the closing of crossings.

Vacant
Exhibit 1510-17

1510.10(3) Midblock Crosswalks

On roadways with pedestrian crossing traffic caused by nearby pedestrian generators, a midblock
crossing may be appropriate. (See 1510.10(2) for crosswalk criteria and the Traffic Manual for
marked crosswalk recommendations at unsignalized intersections.) The approval authority is the
Traffic Engineer.
Engineering judgment of conditions that might increase the value of a midblock crossing includes
the following:
• High pedestrian crossing volume present with long block spacing.
• Evidence of pedestrian-vehicular midblock conflicts (site observations, law enforcement
reporting, and city traffic engineers).
• Proposed crossing with a realistic opportunity to channel multiple pedestrian crossings
to a single location.
• Sight lines that enable sufficient eye contact between motorists and pedestrians.
• Community commitment for a successful outcome.
• Ability to mitigate risks associated with the location using proven countermeasures such
as, but not limited to, refuge islands, rectangular rapid flashing beacons, and/or pedestrian
hybrid beacons.
• Modal interchange points where high volumes crossing pedestrians occur (e.g., transit
stop to apartment complex).
To meet the accessibility criteria, the PAR in the crosswalk may have a cross slope that matches
the grade of the roadway. An example of a midblock crossing is shown in Exhibit 1510-18. (See
Chapter 530 for further information on pedestrian access and paths on limited access facilities.)

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Midblock Pedestrian Crossing

Exhibit 1510-18

1510.10(4) Sight Distance at Crosswalks

When locating crosswalks at intersections, it is important to evaluate the sight lines between
pedestrians and motorists. Shrubbery, signs, parked cars, and other roadside elements can block
motorists’ and pedestrians’ views of one another. Exhibit 1510-19 illustrates these sight distance
concerns.

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Approaching vehicle Driver's line of

Parked car obstructs
sight
line of sight

Crosswalk

Parked cars Pedestrian waiting to

cross street

Conventional right-turn
curb radius

Right-turning
vehicle

Driver's line of
sight

Object blocking driver's

line of sight

Pedestrian waiting to
cross street
Crosswalk

Obstructed Line of Sight at Intersection

Exhibit 1510-19

1510.10(5) Curb Extensions

Curb extensions are traffic calming measures that may improve sight distance and reduce
pedestrian crossing times, which limits pedestrian exposure. Installing a curb extension can help
reduce the sight distance problem with parked cars that limit driver/pedestrian visibility. Curb
extensions may allow for better curb ramp design as well as provide more space for pedestrians.
Note: Curb extensions are not an option on streets with high-speed traffic or without on-street
parking because drivers would be confronted with sudden changes in roadway width. Extend the
curb no farther than the width of the parking lane. (See Chapters 1230, and 1520 for
shoulder/bike lane width guidance.) Design the approach nose to ensure adequate setback of
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vehicles to provide visibility of pedestrians. At intersections with traffic signals, the curb
extensions can be used to reduce pedestrian signal timing. Examples of sidewalk curb extensions
are shown in Exhibits 1510-20 and 1510-21.

Approaching
vehicle
Driver's line
of sight
Crosswalk

Parked cars Pedestrian waiting

to cross street

Improved Line of Sight at Intersection

Exhibit 1510-20

Curb Extension Examples

Exhibit 1510-21

The right-turn path of the design vehicle is a critical element in determining the size and shape
of the curb extension. Sidewalk curb extensions tend to restrict the width of the roadway and

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can make right turns difficult for large trucks. Ensure the geometry of the curb extension is
compatible with the turn path for the design vehicle selected.
Avoid interrupting bicycle traffic with curb extensions.
Do not use curb extensions on state highways when:
• The design vehicle (see Chapter 1300) encroaches on curbs or opposing lanes, and other
solutions will not improve the circumstances.
• On-street parking is not provided/allowed.
• The posted speed is above 35 mph.
Site features such as landscaping, cabinets, poles, benches, planters, bollards, newspaper
stands, and sandwich boards should be selected and placed so they do not obstruct the vision
of pedestrians or drivers within curb extension areas, as shown in Exhibit 1510-21. Take into
account motorist and pedestrian visibility and Design Clear Zone guidelines (see Chapter 1600).

1510.11 Raised Medians/Traffic Islands

Wide multilane streets are often difficult for pedestrians to cross, particularly when there are
insufficient gaps in vehicular traffic because of heavy volumes. Consider raised medians and
traffic islands with a pedestrian refuge area (see Exhibit 1510-22) on roadways with the
following conditions:
• Two-way arterial with intermediate to high speeds (greater than 35 mph), moderate to high
average daily traffic (ADT), and high pedestrian volumes.
• Significant pedestrian crash history.
• Near a school or other community center.
• Crossing distance exceeds 30 feet.
• Complex or irregularly shaped intersections.
A traffic island used for channelized right-turn slip lanes can provide a pedestrian refuge, but the
slip lane may promote faster turning speeds. Minimize the turning radius of the slip lane to keep
speeds as low as feasible. To reduce conflicts, keep the slip lane as narrow as practicable and
design a crosswalk alignment that is at a right angle to the face of curb. (See Chapters 1310 for
turn lanes, 1360 for interchange ramps, and 1320 for pedestrian accommodations in roundabouts.)
The PAR through a raised median or traffic island can be either raised with curb ramps or a cut-
through type (see Exhibit 1510-22). Curb ramps in medians and islands can add difficulty to the
crossing for some users. The curbed edges of cut-throughs can be useful cues to the visually
impaired in determining the direction of a crossing, especially on an angled route through a
median or island.

1510.11(1) Accessibility Criteria for Raised Medians and Traffic Islands

There are many design considerations when deciding whether to ramp up to the median or island
grade or create a cut-through median or island matching the roadway grade. These considerations
may include the profile grade and cross slope of the road, drainage patterns, and the length or
width of the median or island.
The following accessibility criteria apply:
• Each raised median or traffic island shall contain a PAR connecting to each crosswalk (see
1510.07).
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• A passing space shall be provided that is at least 5 feet wide for a distance of at least
5 feet for each PAR in a raised median or on a traffic island (see
Exhibit 1510-22).
Note: It is recommended that cut-throughs be designed to have a minimum width of
5 feet to ensure a passing space is provided.
• Medians and pedestrian refuge islands shall be 6 feet minimum in length in the direction
of pedestrian travel.
• Detectable warning surfaces are to be separated by 2 feet minimum length in the direction
of pedestrian travel.
• Detectable warning surfaces are located at each curb ramp or roadway entrance of a PAR
through a raised median or traffic island. The detectable warning surface shall be located
at the back of the curb (see Exhibit 1510-22).
• PARs of shared-use paths that go through raised medians or traffic islands shall be the same
width as the shared-use path (see Chapter 1515).

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Detectable warning
surface (Typ.)

2' - 0"
Min.

5' - 0"
Min.

Island Cut-Through

Island Cut-Through

Detectable warning
surface (Typ.)

5' - 0"
Min.
Curb ramp
(Typ.)

6' - 0" minimum

2' - 0" Min.
length

Raised Traffic Island With Curb Ramps

Median Island Cut-Through (full width shown)

(See 1510.11(1) for minimum accessibility criteria.)

See the Standard Plans for details.

Raised Islands With Curb Ramps and Pedestrian Cut-Throughs

Exhibit 1510-22

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1510.12 Pedestrian Pushbuttons

Pedestrian pushbuttons are an operating control with their own accessibility requirements. All
pedestrian pushbuttons, regardless of the type of system they are part of, require a level clear
space located so that users of all types can reach the button to actuate the associated system.

1510.12(1) Accessibility Criteria for All Pedestrian Pushbuttons (including APS)

1510.12(1)(a) Location Requirements
• See 1330.04(4) for pushbutton location requirements. These location requirements limit the
potential locations for the pedestrian pushbutton clear space.

1510.12(1)(b) Clear Space Requirements

• Grade: 2% maximum running and cross slopes.
• Clear space dimensions:
a. Standard: 48 inches in width by 60 inches in length, with the pushbutton located along
one of the long sides of the clear space.
b. Minimum: 48 inches minimum width by 48 inches minimum length. Although the ADA
minimum required clear space for an operational control is 30 inches by 48 inches, the
narrow dimension is increased to 48 inches to allow for maneuvering, similar to a curb
ramp landing (see Exhibit 1510-23). If the clear space is constrained on three sides, such
that the clear space is set back 15 inches or more from the PAR, then the clear space shall
be 48 inches minimum width by 60 inches minimum length, to allow for maneuvering
within the constrained space. (see Exhibit 1510-23).
• Additional unobstructed or traversable space of 12 inches on either end of the clear space
should be provided if possible, to allow for protruding equipment such as foot rests to extend
beyond the clear space. This helps mobility assistance device users get their shoulder line
closer to the pushbutton (see Exhibit 1510-23).
• Clear space is allowed to overlap other PAR elements (i.e., sidewalk/curb ramp landing) (see
Exhibits 1510-24a and 1510-24b).
• Clear space must be connected to the crosswalk served by the pedestrian pushbutton with a
PAR.

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Clear Space for Pedestrian Pushbutton

Exhibit 1510-23

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Perpendicular Ramp Concurrent Clear Space Examples

Exhibit 1510-24a

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Parallel Ramp Concurrent Clear Space Examples

Exhibit 1510-24b

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1510.12(1)(c) Reach Range Requirements

Pushbuttons are in locations considered unobstructed, and follow the allowable unobstructed
reach distance requirements of the ADA accessibility requirements. This manual designs clear
space for pushbuttons based on a parallel approach, due to difficulties in both accessibility and
design when attempting to accommodate a forward reach.
• The provided clear space must be within reach range of the pedestrian pushbutton.
• The reach range is 10 inches maximum, as measured from the edge of the clear space to the
center of the physical pushbutton (not just the housing).
• For new construction, the center of the physical pushbutton shall be no more than 9 inches
from the edge of the clear space. It is preferable to locate the pushbutton as close to the edge
of the clear space as possible.
• Different types of pushbuttons (front mount H-frame type versus side mount Accessible
Pedestrian Signal type) will have different reach ranges on the same pole. Generally,
designing for a side mount pushbutton will result in a front mount pushbutton also being
within the required reach range. This is generally not true the other way around. (see Exhibit
1510-25)
• The center of the physical pushbutton shall be 42 inches above the surface of the clear space.
Existing installations may remain if they are within a range of 36 inches minimum to 48
inches maximum above the surface of the clear space.
• The pushbutton shall be a minimum of 12 inches in from both ends of the clear space, and
should be at least 24 inches in from both ends of the clear space. Ideally, the pushbutton
should be centered along one side of the clear space. If the clear space is rectangular, the
pushbutton shall be located along one of the long sides of the clear space.

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NOTE: See Exhibits 1330-14a and 1330-14b for pole setback limits

Reach Range for Pedestrian Pushbuttons

Exhibit 1510-25

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1510.12(2) Accessible Pedestrian Signals (APS)

APS are only installed where there is a pedestrian traffic signal display (walking person / hand).
APS are not installed as part of crosswalk flashing beacon systems. See Chapter 1330 for
additional information on APS equipment.
1510.13 At-Grade Railroad Crossings
The design of pedestrian facilities that cross railroad tracks (see Exhibit 1510-26) often presents
challenges due to the conflicting needs of pedestrians and trains. In particular, the flangeway gap
for trains to traverse a crossing surface may create a significant obstacle for a person who uses
a wheelchair, crutches, or walking aids for mobility. Whenever practicable, align pedestrian
crossings perpendicular to the tracks in order to minimize potential problems related to flangeway
gaps. Crossing surfaces may be constructed of timber planking, rubberized materials, or concrete.
Concrete materials generally provide the smoothest and most durable crossing surfaces. When
detectable warning surfaces are used at railroad crossings, place them according to the MUTCD
stop line placement criteria.

Undesirable Recommended
Pedestrian Railroad Crossings
Exhibit 1510-26
There are a number of railroad crossing warning devices (see Exhibit 1510-27) intended
specifically for pedestrian facilities (see the MUTCD). When selecting warning devices, factors
such as train and pedestrian volumes, train speeds, available sight distance, number of tracks, and
other site-specific characteristics should be taken into account. Coordinate with the HQ Design
Office Railroad Liaison early in the design process so that all relevant factors are considered and
an agreement may be reached regarding the design of warning devices and crossing surfaces.

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Pedestrian Railroad Warning Device

Exhibit 1510-27

Except for crossings located within the limits of first-class cities,* the Washington Utilities and
Transportation Commission (WUTC) approves proposals for any new railroad at-grade crossings
or changes to warning devices or geometry at existing crossings. Additionally, any project that
requires the railroad to perform work such as installation of warning devices or crossing surfaces
must obtain a railroad construction and maintenance agreement. Contact the HQ Design Office
Railroad Liaison to coordinate with both the WUTC and the railroad company.
*RCW 35.22.010: A first class city is a city with a population of ten thousand or more at the time
of its organization or reorganization that has a charter adopted under Article XI, section 10, of the
state Constitution.
Note: There are very few first-class cities in the state of Washington. Verify with the HQ Design
Office Railroad Liaison.

1510.14 Pedestrian Grade Separations (Structures)

On the approach to a bridge that has a raised sidewalk, provide a ramp that transitions to the
sidewalk from the paved shoulder. A ramp that transitions from a paved shoulder to a sidewalk on
a bridge is to have a slope of 5% maximum and be constructed of asphalt or cement concrete. In
addition to aiding pedestrian access, the ramp also serves as a roadside safety feature to mitigate
the raised blunt end of the concrete sidewalk. If a PCP (such as a raised sidewalk or shared-use
path) is located near the bridge, consider eliminating the gap between the bridge sidewalk and the
PCP by extending the bridge sidewalk to match into the nearby PCP.
At underpasses where pedestrians are allowed, it is desirable to provide sidewalks and to maintain
the full shoulder width. When bridge columns are placed on either side of the roadway, it is
preferred to place the walkway between the roadway and the columns for pedestrian visibility
and security. Provide adequate illumination and drainage for pedestrian safety and comfort.
In cases where there is a pedestrian crash history, and the roadway cannot be redesigned
to accommodate pedestrians at grade, planners should consider providing a grade-separated
pedestrian structure (see Exhibits 1510-28 and 1510-29). When considering a grade-separated
pedestrian structure, determine whether the conditions that require the crossing are permanent. If
there is likelihood that pedestrians will not use a grade separation, consider less-costly solutions.
Locate the grade-separated crossing where pedestrians are most likely to cross the roadway.
A crossing might not be used if the pedestrian is required to deviate significantly from a more
direct route.

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It is sometimes necessary to install fencing or other physical barriers to channel the pedestrians
to the structure and reduce the possibility of undesired at-grade crossings. Note: The HQ Bridge
and Structures Office is responsible for the design of pedestrian structures.
Consider a grade-separated crossing where:
• There is moderate to high pedestrian demand to cross a freeway or expressway.
• There are large numbers of young children, particularly on school routes, who regularly cross
high-speed or high-volume roadways.
• The traffic conflicts that would be encountered by pedestrians are considered unacceptable
(such as on wide streets with high pedestrian volumes combined with high-speed traffic).
• There are documented crashes or close calls involving pedestrians and vehicles
• One or more of the conditions stated above exists in conjunction with a well-defined
pedestrian origin and destination (such as a residential neighborhood across a busy street
from a school).

1510.14(1) Pedestrian Bridges

Pedestrian grade-separation bridges (see Exhibit 1510-28) are more effective when the roadway
is below the natural ground line, as in a cut section. Elevated grade separations in cut sections,
where pedestrians climb stairs or use long approach ramps, tend to be underused. Pedestrian
bridges need adequate right of way to accommodate accessible ramp approaches leading up
to and off of the structure. The bridge structure must comply with ADA requirements and meet
the accessibility criteria for either a pedestrian circulation path (if the grade is 5% or less) or an
access ramp (if the grade is greater than 5% but less than or equal to 8.3%), and must include a
pedestrian access route. (See 1510.06 and 1510.07 for PCP and PAR accessibility criteria; see
1510.15(2) for access ramp accessibility criteria.)
For the minimum vertical clearance from the bottom of the pedestrian structure to the roadway
beneath, see Chapter 720. The height of the structure can affect the length of the pedestrian ramp
approaches to the structure. When access ramps are not feasible, provide both elevators and
stairways.
Provide railings on pedestrian bridges. Protective screening is sometimes desirable to deter
pedestrians from throwing objects from an overhead pedestrian structure (see Chapter 720).
The minimum clear width for pedestrian bridges is 8 feet. Consider a clear width of 14 feet where
a pedestrian bridge is enclosed or shared with bicyclists, or equestrians, or if maintenance or
emergency vehicles will need to access.

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Pedestrian Bridges
Exhibit 1510-28

1510.14(2) Pedestrian Tunnels

Tunnels are an effective method of providing crossings for roadways located in embankment
sections. Well-designed tunnels can be a desirable crossing for pedestrians. When feasible, design
the tunnel with a nearly level profile to provide an unobstructed line of sight from portal to portal
(see Exhibit 1510-29). People may be reluctant to enter a tunnel with a depressed profile because
they are unable to see whether the tunnel is occupied. Law enforcement also has difficulty
patrolling depressed profile tunnels.
Provide vandal-resistant daytime and nighttime illumination within the pedestrian tunnel.
Installing gloss-finished tile walls and ceilings can enhance light levels within the tunnel.
The minimum overhead clearance for a pedestrian tunnel is 10 feet. The minimum width
for a pedestrian tunnel is 12 feet. Consider a tunnel width between 14 and 18 feet depending
on usage and the length of the tunnel.

Pedestrian Tunnel
Exhibit 1510-29

Pedestrian tunnels need adequate right of way to accommodate accessible approaches leading
to the tunnel structure. The tunnel structure must comply with ADA requirements and meet the
accessibility criteria for either a pedestrian circulation path (if the grade is less than or equal to
5%) or an access ramp (if the grade is greater than 5% and less than or equal to 8.3%), and must
include a pedestrian access route. (See 1510.06 and 1510.07 for PCP and PAR accessibility
criteria; see 1510.15(2) for access ramp accessibility criteria.)
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1510.15 Other Pedestrian Facilities

1510.15(1) Transit Stops and School Bus Stops
The location of transit stops is an important element in providing appropriate pedestrian facilities.
(Coordinate with the local transit provider.) Newly constructed transit stops must conform to
ADA requirements. Design newly constructed transit stops so that they are accessible from the
sidewalk or paved shoulder. A transit stop on one side of a street usually has a counterpart on the
opposite side because transit routes normally function in both directions on the same roadway.
Provide adequate crossing facilities for pedestrians.
When locating a transit stop (see Traffic Manual 7.9), consider transit ridership and land use
demand for the stop. Also, take into account compatibility with the following roadway/traffic
characteristics:
• ADT
• Traffic speed
• Crossing distance
• Crash history
• Sight distance
• Connectivity to a pedestrian access route
• Traffic generator density
If any of these suggests an undesirable location for a pedestrian crossing, consider a controlled
crossing or another location for the transit stop. (See Chapter 530 for further information on bus
stops on limited access facilities.)
When analyzing a transit stop location with high pedestrian crash frequency, take into account
the presence of nearby transit stops and opportunities for pedestrians to cross the street in a
reasonably safe manner. At-grade midblock pedestrian crossings may be effective at transit stop
locations on roadways with lower vehicular volumes. Pedestrian grade separations are appropriate
at midblock locations when vehicular traffic volumes prohibit pedestrian crossings at grade. (See
the Traffic Manual for recommendations for marked crosswalks at unsignalized intersections.)
School bus stops are typically adjacent to sidewalks in urban areas and along shoulders in rural
areas. Determine the number of children using the stop and provide a waiting area that allows the
children to wait for the bus. Coordinate with the local school district. Because of their smaller
size, children might be difficult for motorists to see at crossings or stops. Determine whether
utility poles, vegetation, and other roadside features interfere with motorists’ ability to see the
children. When necessary, remove or relocate the obstructions or move the bus stop. Parked
vehicles can also block visibility, and parking prohibitions might be advisable near the bus
stop. Coordinate transit and school bus stop locations with the region Traffic Office.

1510.15(2) Access Ramps Serving Transit Stops, Park & Ride Lots, Rest Areas,
Buildings, and Other Facilities
An access ramp (see Exhibit 1510-30) provides an accessible pedestrian route from a pedestrian
circulation path to a facility such as a transit stop, park & ride lot, rest area, pedestrian
overcrossing/undercrossing structure, or building. When the running slope is 5% or less, it can be
designed as a pedestrian circulation path that includes a pedestrian access route. When
the running slope is greater than 5% to a maximum of 8.3%, it must be designed as an access
ramp. (See 1510.06 and 1510.07 for PCP and PAR accessibility criteria; see 1510.15(2)(a) for
access ramp accessibility criteria.)

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1510.15(2)(a) Accessibility Criteria for Access Ramps

Access ramps are composed of one or more ramp segments interconnected by level landings.
Unless superseded by the following specific accessibility requirements for access ramps, the
accessibility requirements for pedestrian access routes also apply:
• Ramp segments shall have a maximum running slope of 8.3%.
• The cross slope of ramp segments shall be 2% maximum.
• The minimum clear width of ramps is 4 feet; however, it is desirable to match the width
of the connecting pedestrian facility.
• The rise for any ramp segment shall be 30 inches maximum.
• A level landing (2% maximum running and cross slopes) shall be provided at the top and
bottom of each access ramp segment.
• An access ramp landing’s clear width shall be at least as wide as the widest ramp segment
leading to the landing.
• An access ramp landing’s length shall be 5 feet minimum.
• Access ramps that change direction between ramp segments at landings shall have a level
landing 5 feet minimum width by 5 feet minimum length.
• All access ramp segments with a rise greater than 6 inches shall have ADA-compliant
handrails (see 1510.15(3) for handrail accessibility criteria).
Provide edge protection complying with one of the two following options on each side of access
ramp segments:
• The surface of the ramp segment and landing shall extend 12 inches minimum beyond the
inside face of the handrail.
• A curb or barrier shall be provided that does not allow the passage of a 4-inch-diameter
sphere, where any portion of the sphere is within 4 inches of the ramp/landing surface.

Access Ramp With Accessible Handrails

Exhibit 1510-30

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Chapter 1510 Pedestrian Facilities

1510.15(3) Railings and Handrails for Pedestrian Facilities

Accessible handrails are required on stairs and also on access ramps that have a rise greater than
6 inches (see 1510.15(2)(a) for access ramp accessibility criteria). If the height of a drop-off
(typically greater than 30 inches) adjacent to a pedestrian facility necessitates the need to protect
pedestrians from falls, then a more robust railing system designed for fall protection should be
used. If the drop-off is adjacent to either a stairway or an access ramp with a rise greater than
6 inches, then a combined railing system that meets the requirements for both accessibility and
fall protection must be used.

1510.15(3)(a) Fall Protection Railing

Railing designed for fall protection alone is typically placed adjacent to pedestrian facilities other
than stairs or access ramps to prevent pedestrians or bicyclists from falls. The minimum railing
height for pedestrian fall protection is 42 inches. For facilities where bicycle traffic is anticipated,
such as on a grade-separation structure on a shared-use facility (see Chapter 1515), the minimum
railing height for bicyclist fall protection is 54 inches.
1510.15(3)(b) Accessible Fall Protection Railing
When fall protection is needed adjacent to stairs or an access ramp that has a rise greater than
6 inches, then a combined railing system that meets both the accessibility criteria for handrail
outlined in 1510.15(3)(d) and the requirements for fall protection must be used. The minimum
railing height for pedestrian fall protection is 42 inches. For facilities where bicycle traffic is
anticipated, such as on the approach to a grade-separation structure on a shared-use facility
(see Chapter 1515), the minimum railing height for bicyclist fall protection is 54 inches.

1510.15(3)(c) Accessible Handrail

Accessible handrail meeting the accessibility criteria listed in 1510.15(3)(d) that is not designed
to provide fall protection is to be used adjacent to stairs or access ramps that have a rise greater
than 6 inches at locations where robust fall protection is not needed.

1510.15(3)(d) Accessibility Criteria for Handrail

The following accessibility criteria apply to all handrail installations provided at stairs and access
ramps that have a rise greater than 6 inches.
1. Height
• The top of handrail gripping surfaces shall be 34 inches minimum and 38 inches
maximum vertically above walking surfaces, stair nosings, and ramp surfaces.
• The mounting height of the handrail shall also be at a consistent height.
2. Gripping Surface
• Clearance between handrail gripping surfaces and adjacent surfaces shall be 1½ inches
minimum.
• Handrail gripping surfaces shall be continuous along their length and shall not be
obstructed along their tops or sides.
• The bottoms of handrail gripping surfaces shall not be obstructed for more than 20%
of their length.
• Where provided, horizontal projections shall be located 1½ inches minimum below the
bottom of the handrail gripping surface.

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Pedestrian Facilities Chapter 1510

• Handrail gripping surfaces with a circular cross section shall have an outside diameter
between 1¼ inches minimum and 2 inches maximum.
• Handrail gripping surfaces with a noncircular cross section shall have a perimeter
dimension between 4 inches minimum and 6¼ inches maximum, and a cross section
dimension of 2¼ inches maximum.
• Handrail gripping surfaces and the surfaces adjacent to them shall be free of sharp
or abrasive elements and shall have rounded edges.
• Handrails shall not rotate in their fittings.
3. Placement and Continuity

• Handrails shall be provided on both sides of access ramps and stairs.

• Handrails shall be continuous within the full length of each access ramp run or stair
flight.
• Inside handrails on switchback or dogleg access ramps and stairs shall be continuous
between runs or flights.
4. Extensions

• Access ramp handrails shall extend horizontally above the landing for 12 inches
minimum beyond the top and bottom of ramp runs.
• At the top of a stair flight, handrails shall extend horizontally above the landing for
12 inches minimum beginning directly above the first riser nosing.
• At the bottom of a stair flight, handrails shall extend at the slope of the stair flight for
a horizontal distance at least equal to one tread depth beyond the last riser nosing.
• Handrail extensions shall return to a wall, guard, or the landing surface, or shall
be continuous to the handrail of an adjacent access ramp run or stair flight.
Exception: Handrail extensions shall not be required for continuous handrails
at the inside turn of switchback or dogleg access ramps or stairs.

1510.15(4) Other Pedestrian Facilities, Features, and Elements

This chapter covers the accessibility criteria for the most commonly encountered pedestrian
design elements in the public right of way. However, there are ADA requirements that apply to
any feature or element for pedestrian use, such as doorways, elevators, stairs, call boxes, and
drinking fountains. For accessibility criteria for less commonly encountered pedestrian design
elements, consult the applicable federal guidance document(s) listed in 1510.02(2).

1510.16 Illumination and Signing

In Washington State, the highest number of crashes between vehicles and pedestrians tends to
occur during November through February, when there is poor visibility and fewer daylight hours.
Illumination of pedestrian crossings and other walkways is an important design consideration
because lighting has a major impact on a pedestrian’s safety and sense of security. Illumination
provided solely for vehicular traffic is not always effective in lighting parallel walkways for
pedestrians. Consider pedestrian-level (mounted at a lower level) lighting for PCPs, intersections,
and other pedestrian crossing areas with high nighttime pedestrian activity, such as shopping
districts, transit stops, schools, community centers, and other major pedestrian generators or areas
with a history of pedestrian crashes. (See Chapter 1040 for design guidance on illumination, and
Chapter 1020 and the MUTCD for pedestrian-related signing.)

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1510.17 Work Zone Pedestrian Accommodation

While Title II of the ADA requires that a public entity maintain its pedestrian facilities in
operable working condition, including maintenance of their accessibility features, construction
and maintenance activities often temporarily disrupt these facilities. When this occurs, provide
access and mobility for pedestrians through and around work zones (see Exhibit 1510-31).
Address this in the temporary traffic control plans if the project occurs in a location accessible
to pedestrians. The designer must determine pedestrian needs in the proposed work zone during
the public input process and through field visits.
Detailed guidance on work zone pedestrian accommodation can be found in the WSDOT Field
Guide for Accessible Public Rights of Way, the MUTCD, and Chapter 1010.
Some work zone considerations include:
• Separate pedestrians from conflicts with work zone equipment and operations.
• Separate pedestrians from traffic moving through or around the work zone.
• Provide pedestrians with alternate routes that have accessible and convenient travel paths that
duplicate, as closely as feasible, the characteristics of the existing pedestrian facilities.
Provide walkways that are clearly marked and pedestrian barriers that are continuous, rigid, and
detectable to vision-impaired persons who navigate with a cane. Also, keep:
• The pedestrian head space clear.
• Walkways free from pedestrian hazards such as holes, debris, and abrupt changes in grade
or terrain.
• Access along sidewalks clear of obstructions such as construction traffic control signs.
• A minimum clear width path throughout: 4 feet for pedestrians or 10 feet for pedestrians
and bicyclists.
Temporary pedestrian facilities within the work zone must meet accessibility criteria to the
maximum extent feasible. (See 1510.06 and 1510.07 for pedestrian circulation path and
pedestrian access route accessibility criteria.)
Consider the use of flaggers if pedestrian generators such as schools are in the work zone vicinity.
Consider spotters who are prepared to help pedestrians through the work zone.
Provide for advance public notification of sidewalk closures in the contract special provisions and
plans.
Where transit stops are affected or relocated because of work activity, provide an accessible route
to temporary transit stops.

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Meets ADA requirements Does not meet ADA requirements

Work Zones and Pedestrian Facilities

Exhibit 1510-31

1510.18 Documentation
Refer to Chapter 300 for design documentation requirements.

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Chapter 1515 Shared-Use Paths
1515.01 General
1515.02 Shared-Use Path Design
1515.03 Intersections and Crossings Design
1515.04 Grade Separation Structures
1515.05 Signing, Pavement Markings, and Illumination
1515.06 Restricted Use Controls
1515.07 Documentation

1515.01 General
Shared-use paths are designed for both transportation and recreation purposes and are used by
pedestrians, bicyclists, skaters, equestrians, and other users. Some common locations for
shared-use paths are along rivers, streams, ocean beachfronts, canals, utility rights of way, and
abandoned railroad rights of way; within college campuses; and within and between parks as
well as within existing roadway corridors. A common application is to use shared-use paths to
close gaps in bicycle networks. There might also be situations where such facilities can be
provided as part of planned developments. Where a shared-use path is designed to parallel a
roadway, provide a separation between the path and the vehicular traveled way in accordance
with this chapter.

As with any roadway project, shared-use path projects need to fit into the context of
a multimodal community. Exhibits are provided throughout this chapter to illustrate possible
design solutions, which should be treated with appropriate flexibility as long as doing so
complies with corresponding laws, regulations, standards, and guidance. Engage various
discipline experts, including landscape architects, soil and pavement engineers, maintenance
staff, traffic control experts, ADA and bicycle coordinators, and others. Additionally, when
designing such facilities, consider way-finding.

This chapter includes technical provisions for making shared-use paths accessible to persons
with disabilities. Design shared-use paths and roadway crossings in consultation with your
region’s ADA Coordinator, Bicycle Coordinator, and State Bicycle and Pedestrian Coordinator.
For additional information on pedestrian and bicycle facilities, see Chapters 1510 and 1520,
respectively.

1515.02 Shared-Use Path Design

When designing shared-use paths, the bicyclist may not be the critical design user for every
element of design. For example, the crossing speeds of most intersections between roads and
pathways should be designed for pedestrians, as they are the slowest users. Accommodate all
intended users, and minimize conflicts. When designing to serve equestrians, it is desirable to
provide a separate bridle trail along the shared-use path to minimize conflicts with horses.

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Exhibit 1515 - 1 Shared-Use Path

1515.02(1) Design Speed

The design speed for a shared-use path is based on bicycle use and is dependent on the terrain
and the expected conditions of use. Design the shared-use path to encourage bicyclists to
operate at speeds compatible with other users. Higher speeds are discouraged in a mixed-use
setting. Design shared-use paths to maintain speeds at or below the speeds shown in Exhibit
1515-2 by designing to the horizontal curve radii shown.

Exhibit 1515 - 2 Bicycle Design Speeds

Design Speed Curve

Conditions
(mph) Radius (ft)
Long downgrades (steeper than 4%
and longer than 500 ft) 30 166

Open country (level or rolling);

shared-use paths in urban areas 20 74

Approaching intersections 12 27

When minimum radius curves cannot be obtained because of right of way, topographical, or
other constraints, consider installing the following mitigation measures for traffic calming to
slow bicyclists when approaching curves:
 Intermittent curves to slow or maintain desired speeds.
 Standard curve warning signs and supplemental pavement markings in accordance
with the MUTCD.

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Chapter 1515 Shared-Use Paths

 Perpendicular stripes painted on the pathway in decreasing intervals to provide the

perception of increased speed. This has been shown to slow drivers when applied
to roadways.
 Changes in pavement texture to encourage reductions in speed at tight curve
approaches.

The negative effects of tight radius curves can also be partially offset by widening the pavement
through the curves. Steeper vertical grades affect the running speed of bicycles. A shared-use
path should be designed not to exceed 5%. Refer to 1515.04(3) for further guidance.

1515.02(2) Widths, Cross Slopes, Side Slopes, and Clearances

1515.02(2)(a) Shared-Use Path Widths

The appropriate paved width for a shared-use path depends on the context, volume, and mix of
users. The desirable paved width of a shared-use path, excluding the shoulders on either side, is
12 feet. The minimum paved width, excluding the shoulders on either side, is 10 feet.

A paved width of more than 12 feet, excluding the shoulders on either side, may be appropriate
when substantial use by both pedestrians and bicyclists is expected or maintenance vehicles are
anticipated.

Shared-use path shoulders are typically unpaved and 2 feet wide on either side. Exhibits 1515-3
through 1515-5 provide additional information and cross-sectional elements.

On bridges or tunnels, it is common to pave the entire shared-use path, including shoulders. This
usable width can be advantageous for emergency, patrol, and maintenance vehicles and allows
for maneuvering around pedestrians and bicyclists who may have stopped. It also keeps the
structure uncluttered of any loose gravel shoulder material.
1515.02(2)(b) Exceptions to Minimum Path Widths

A reduced path width of 8 feet may be designed at locations that present a physical constraint
such as an environmental feature or other obstacle. Refer to the MUTCD for signing and
pavement markings for such conditions.
In very rare circumstances, a reduced width of 8 feet may be used where the following
conditions prevail:
 Bicycle traffic is expected to be low, even on peak days or during peak hours.
 Pedestrian use of the facility is not expected to be more than occasional.
 Horizontal and vertical alignments provide frequent, well-designed passing and
resting opportunities.
 The shared-use path will not be regularly subjected to maintenance vehicle loading
conditions that would cause pavement edge damage.
 The share-use path is a short distance such as a spur connection to a neighborhood.

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1515.02(2)(c) Existing Shared-Use Paths – Considerations

Some existing shared-use paths were constructed with narrower dimensions, generally
providing 8 feet of pavement. Evaluate existing older paths for current needs. Consider widening
an existing shared-use path to meet current geometric standards.

1515.02(2)(d) Cross Slope

The maximum cross slope on a paved shared-use path is to be 2%. The cross slope of the
shoulders can be no steeper than 6H:1V. To accommodate drainage, the entire section,
including shoulders, should transition through curves. It is desirable to design the pivot point on
the outside edge of one side of the shoulder or the other to avoid a pavement crown (see
Exhibits 1515-3 through 1515-5).

It is best practice to design the cross slope to be less steep than the allowed maximum to
account for some tolerance in construction. For example, design for a 1.5% cross slope (rather
than the 2% maximum).

Sloping the pavement surface to one side is desirable and usually simplifies drainage design and
surface construction. Generally, surface drainage from the path is dissipated as it flows down
the side slope.

1515.02(2)(e) Side Slopes and Pedestrian Rail

Side slopes along shared-use paths are an important design feature. Embankment side slopes of
6H:1V or flatter provide a gently sloping path border.

For shared-use paths with side slopes steeper than 3H:1V, or where obstacles or waterways may
exist, evaluate the potential risk and provide mitigation such as:
 A minimum 5-foot separation from the edge of the pavement to the embankment
edge. This can be accomplished by providing a 5-foot shoulder as shown in Exhibit
1515-5, Example 2.
 A natural barrier such as dense shrubbery on the side slopes.
 A physical barrier, such as a pedestrian rail.
 Where a shared-use path is adjacent to a vertical drop of 2 feet 6 inches or more, a
pedestrian rail is needed (see Exhibit 1515-5, Example 4).
 If the vertical drop is less than 2 feet 6 inches, a pedestrian rail, chain link fence, or
4-inch curb at the edge of the shared-use path may be installed to delineate the
edge.
 Where a shared-use path is constructed on the side of a hill, drainage facilities may
need to be considered.
1515.02(2)(f) Clearances

The minimum horizontal clearance from the edge of pavement to an obstruction (such as bridge
piers or guardrail) is 2 feet. For vertical clearances see 1515.04 Grade Separation Structures.

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Exhibit 1515 - 3 Two-Way Shared-Use Path: Independent Alignment

Exhibit 1515 - 4a Two-Way Shared-Use Path: Adjacent to Roadway (≤ 35 mph)

Note:
[1] 3 ft minimum. Provide as much separation from the roadway as practicable.

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Exhibit 1515-4b Two-Way Shared-Use Path: Adjacent to Roadway (> 35mph)

Notes:
A separation greater than 5 feet is required for path user comfort. If separation greater than 5 feet cannot be
obtained, provide barrier separation in accordance with Exhibit 1515-4c.
See Chapter 1600 for roadway clear zone design guidance for fixed objects.

Exhibit 1515-4c Two-Way Shared-Use Path: Attached to Roadway (> 35mph)

Notes:
It is desirable for the cross slope to slope toward grass areas for drainage.

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Chapter 1515 Shared-Use Paths

See Chapter 1610 for barrier design. Pedestrian rail height minimum is 42 inches.

Exhibit 1515 - 5 Shared-Use Path Side Slopes and Railing

2 ft
min Pedestrian Railing
Not
stee
p
3H: er than 42 in min
1V 2 ft

Example 1: Embankment min

Based on context, flatter slopes are desirable.

WALL
≥ 2.5 ft = 30 in

Example 4: Railing used at drop off

2 ft 3 ft
Apply railing or fencing a minimum of 42 inches
min min high when a drop off is present, such as along a
Stee retaining wall. Consult with the Region Materials
per
3H:1 than Engineer to determine if the shoulder along the
V
wall should be paved.
Example 2: Shoulder widening to 5 feet or
more
Used with steeper fill slopes to provide clear Note: These drawings depict some common
space between the hinge point and path. applications for various slope alternatives.
Vegetation can also be used as a buffer on
slopes. Consider a natural or physical barrier in
lieu of 3 ft additional widening.

n r
2 ft e gio ee
R gin
min s u l t En
n ls
2:1 Co eria
at
M
0.5 ft min

Example 3: Cut section with ditch

Consult with the Region Materials Engineer to
determine for appropriate cut slopes.

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1515.02(3) Running Slopes, Landings, and Rest Areas

1515.02(3)(a) Running Slopes

Design running slopes (grades) on shared-use paths less than or equal to 5% to accommodate all
user types, including pedestrians with disabilities.

When the path is within the highway right of way, its running slope can match the general grade
established for the adjacent roadway.

1515.02(3)(b) Landings

Shared-use path landings provide users a level place to rest on extended grades. Exhibits 1515-6
and 1515-7 show these features.

Design landings to:

 Permit users to stop periodically and rest.
 Not exceed maximum running slopes and cross slopes of 2%.
 Be in line and as wide as the shared-use path. Landings are to be at least 5 feet long.
 Avoid abrupt grade changes or angle points. Design transitions to landings
using vertical curves.

Exhibit 1515 - 6 Shared-Use Path Landing Profile

Landing

Landing

2.0% max.

5' min

2.0% max.

5' min ≤ 5% - No max length

Notes:
Landings are desirable on extended grades.
Design vertical curves to transition from the grade to the landing.
Exhibit 1515-7 illustrates a landing and a rest area.

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1515.02(3)(c) Rest Areas

Although not required, rest areas may be provided adjacent to the shared-use path outside of
the path travelled way as shown in Exhibit 1515-7.

Requirements for rest areas include:

 The maximum running slope and cross slopes are 2%.
 The minimum size is to be 5 feet by 5 feet.
 If features such as benches are provided, they must meet ADA requirements;
consult with the region ADA Coordinator for guidance.

Exhibit 1515 - 7 Shared-Use Path Landing and Rest Area

Notes:
Design inline landings at least 5 feet long and as wide as the shared-use path.
Design inline landings with a maximum cross slope and running slope of 2%.

1515.02(4) Pavement Structural Section

Design the pavement structural section of a shared-use path in the same manner as a highway,
considering the quality of the subgrade and the anticipated loads on the path. (Design loads are
normally maintenance and emergency vehicles.) Provide a firm, stable, slip-resistant pavement
surface.

Design the pavement structural section as recommended by the Region Materials Engineer.

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Use crushed rock or other suitable material for shoulder graded areas as recommended by the
Region Materials Engineer. On bridges or tunnels, it is common to pave the entire shared-use
path, including shoulders across the structure.

1515.02(5) Stopping Sight Distance

The distance needed to bring a shared-use path user to a complete stop is a function of the
user’s perception and braking reaction time, the initial speed, the coefficient of friction between
the wheels and the pavement, the braking ability of the user’s equipment, and the grade.
Exhibits 1515-14a and 14b provide a graph and an equation to obtain minimum stopping sight
distances for various design speeds and grades.
1515.02(5)(a) Stopping Sight Distance on Crest Vertical Curves

Exhibit 1515-15 provides a chart or equations to obtain the minimum lengths of crest vertical
curves for varying stopping sight distances and algebraic differences in grade. The values are
based on a 4.5-foot eye height for the bicyclist and a 0-foot height for the object (path surface).
1515.02(5)(b) Stopping Sight Distance on Horizontal Curves

Exhibit 1515-16 gives the minimum clearances to line-of-sight obstructions for sight distance on
horizontal curves. Provide lateral clearance based on the sum of stopping sight distances from
Exhibits 1515-14a and 14b for bicyclists traveling in both directions and the proposed horizontal
curve radius. Where this minimum clearance cannot be obtained, provide curve warning signs
and use centerline pavement markings in accordance with the MUTCD.

Exhibits 1515-14a, 14b, 15, and 16 are presented at the end of the chapter.

1515.03 Intersections and Crossings Design

This section covers path/roadway intersections and grade-separated crossings. Detectable
warning surfaces are required where shared-use paths connect to the roadway.

1515.03(1) Intersections with Roadways

Clearly define who has the right of way and provide sight distance for all users at shared-use
path and roadway intersections.

The common types of shared-use path/roadway at-grade intersection crossings are midblock
and adjacent.

For roadway intersections with roundabouts, see Chapter 1320.

Midblock crossings are located between roadway intersections. When possible, locate the path
crossings far enough away from intersections to minimize conflicts between the path users and
motor vehicle traffic. It is preferable for midblock path crossings to intersect the roadway at an
angle as close to perpendicular as practicable. A minimum 60-degree crossing angle is
acceptable to minimize right of way needs. A diagonal midblock crossing can be altered as
shown in Exhibit 1515-8.

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There are other considerations when designing midblock crossings. They include traffic right of
way assignments; traffic control devices; sight distances for both bicyclists and motor vehicle
operators; refuge island use; access control; and pavement markings.

Exhibit 1515 - 8 Typical Redesign of a Diagonal Midblock Crossing

See Chapter 1510 and

the Standard Plans for Path
detectible warning surface
and other accessibility
requirements.

Intersecting roadway
or railroad

Path

Notes:
For path and highway signing and markings, see the MUTCD and the Standard Plans.
 http://www.wsdot.wa.gov/publications/fulltext/Standards/english/PDF/m09.60-00_e.pdf
For radii approaching roadway intersections, see Exhibit 1515-2.

Adjacent path crossings are located at or near public intersection crosswalks and are normally
placed with them. These crossings are usually placed with pedestrian crossings, where motorists
can be expected to stop. If alternate intersection locations for a shared-use path are available,
select the one with the greatest sight distance.

Adjacent path crossings occur where a path crosses an existing intersection of two roadways, a T
intersection (including driveways), or a four-way intersection, as shown in Exhibit 1515-9. It is
desirable to integrate this type of crossing close to an intersection so that motorists and path
users recognize one another as intersecting traffic. The path user faces potential conflicts with
motor vehicles turning left (A) and right (B) from the parallel roadway and on the crossed
roadway (C, D, and E).

Consider crossing improvements on a case-by-case basis. Suggested improvements include:

move the crossing; evaluate existing or proposed intersection control type; change signalization
timing; or provide a refuge island and make a two-step crossing for path users.

Important elements that greatly affect the design of these crossings are traffic right of way
assignments, traffic control devices, and the separation distance between path and roadway.

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Exhibit 1515 - 9 Adjacent Shared-Use Path Intersection

Intersecting Roadway

Parallel Roadway E

Path

See Chapter
1510 and the
Standard Plans.
C D

Note:
For signing and pavement markings, see the MUTCD and the Standard Plans.

Additional Roadway/Path Intersection Design Considerations

Additional roadway/path intersection design considerations include the following:

Evaluate Intersection Control

Determine the need for traffic control devices at path/roadway intersections by using MUTCD
warrants and engineering judgment. Bicycles are considered vehicles in Washington State, and
bicycle path traffic can be classified as vehicular traffic for MUTCD warrants. Provide traffic
signal timing set for pedestrians.

Signal Actuation Mechanisms

Place the manually operated accessible pedestrian pushbutton in a location that complies with
ADA requirements. For additional information, see Chapters 1330 and 1510. A detector loop in
the path pavement may be provided in addition to the manually operated accessible pedestrian
push button.

Signing
Provide sign type, size, and location in accordance with the MUTCD. Place path STOP signs as
close to the intended stopping point as feasible. Do not place the shared-use path signs where

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they may confuse motorists or place roadway signs where they may confuse shared-use path
users. For additional information on signing, see the MUTCD and Chapter 1020.

Approach Treatments
Design shared-use path and roadway intersections with level grades, and provide sight
distances. Provide advance warning signs and pavement markings that alert and direct path
users that there is a crossing (see the MUTCD). Do not use speed bumps or other similar surface
obstructions intended to cause bicyclists to slow down. Consider some slowing features such as
horizontal curves (see Exhibits 1515-2 and 1515-8). Avoid locating a crossing where there is a
steep downgrade where bike speeds could be high.

Sight Distance
Sight distance is a principal element of roadway and path intersection design. At a minimum,
provide stopping sight distance for both the roadway and the path at the crossing. Decision sight
distance is desirable for the roadway traffic. Refer to Chapter 1260 for stopping sight distance
for the roadway and 1515.04(5) for shared-use path stopping sight distance.

Curb Ramp Widths

Design curb ramps with a width equal to the shared-use path. Curb ramps and barrier-free
passageways are to provide a smooth transition between the shared-use path and the roadway
or sidewalk (for pedestrians). Curb ramps at path/ roadway intersections must meet the
requirements for curb ramps at a crosswalk. For design requirements, see Chapter 1510, and for
curb ramp treatments at roundabouts, see Chapter 1320.

Refuge Islands
Consider refuge islands where a shared-use path crosses a roadway when one or more of the
following applies:
 High motor vehicle traffic volumes and speeds
 Wide roadways
 Use by the elderly, children, the disabled, or other slow-moving users

The refuge area may either be designed with the storage aligned perpendicularly across the
island or be aligned diagonal (as shown in Exhibit 1515-10). The diagonal storage area has the
added benefit of directing attention toward oncoming traffic since it is angled toward the
direction from which traffic is approaching.

1515.03(2) At-Grade Railroad Crossings

Wherever possible, design the crossing at right angles to the rails. For signing and pavement
marking for a shared-use path crossing a railroad track, see the MUTCD and the Standard Plans.
Also, see Chapter 1510 for design of at-grade pedestrian railroad crossings.

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Exhibit 1515 - 10 Roadway Crossing Refuge Area

Roadway
Shoulder
L

Sidewalk
Raised Island
X
Ramp Landing Ramp

Shared-Use Path
Y
Shared-Use Path

L = Length of taper
Sidewalk

(see Chapter 1210

for taper rates)

X = Length of island
each side of path

Shoulder
not less than L
Roadway

Y = Width of refuge
6 ft = minimum
10 ft = maximum
For striping details, see the
Standard Plans and the MUTCD.

For ADA requirements, see

Chapter 1510.

Note:
This exhibit shows a case where a path intersects a roadway framed with both a sidewalk and a paved shoulder,
for the purpose of showing detectible warning surface placements.

1515.04 Grade Separation Structures

Provide the same minimum clear width as the approach paved shared-use path plus the graded
clear areas.

Carrying full widths across structures has two advantages:

 The clear width provides a minimum horizontal shy distance from the railing or
barrier.
 It provides needed maneuvering room to avoid pedestrians and other bicyclists.

For undercrossings and tunnels, it is the Designer’s responsibility to determine the correct
minimum vertical clearance (shared use path pavement surface to overhead obstruction) of

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Chapter 1515 Shared-Use Paths

each undercrossing or tunnel based on coordination with maintenance and emergency services.
The minimum vertical clearance for bicyclists and equestrians is 10 feet.

Consult the region Maintenance Office and the HQ Bridge Preservation Office to verify that the
planned path width and vertical clearance meets their needs. If not, widen and/or increase
vertical clearance to their specifications.

Use expansion joints that accommodate shared-use path users. Expansion joints should be
perpendicular to the path and have a maximum gap of ½ inch or be covered with a slip-resistant
plate.

The installation of protective screening is analyzed on a case-by-case basis. Refer to Chapter 720
for guidance.

Exhibit 1515 - 11 Shared-Use Path Bridge and Approach Walls

Note:
On structures, the bridge railing type and height are part of the structure design. Contact the HQ Bridge and
Structures Office for additional information.

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Exhibit 1515 - 12 Bridge and Pedestrian Rail

Notes:
The photo above shows a bridge with a shared-use path separating the users from the roadway. Pedestrian rail is
used on the outside edge.
On structures, the bridge railing type and height are part of the structure design. Contact the HQ Bridge and
Structures Office for additional information.

1515.05 Signing, Pavement Markings, and Illumination

Generally, WSDOT does not provide continuous centerline striping or channelization for user
modes on shared-use paths. However, signing and pavement markings can be beneficial to warn
shared-use path users of curves, grades, obstructions, and intersections.

Refer to the MUTCD for guidance and directions regarding signing (regulatory, warning, and way
finding) and pavement markings.

The Standard Plans shows shared-use path pavement markings at obstructions in accordance
with the MUTCD and also shows placement of detectible warning surfaces.

For pavement marking around bollards and other obstructions, see Standard Plan M-9.60:
 http://www.wsdot.wa.gov/publications/fulltext/standards/english/pdf/m09.60-00_e.pdf

The level of illumination on a shared-use path is dependent on the amount of nighttime use
expected and the nature of the area surrounding the facility. If illumination is used, provide
illumination in accordance with Chapter 1040.

1515.06 Restricted Use Controls

This section presents considerations on use of fencing and other treatments to restrict roadway
and path users to their domains.

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1515.06(1) Fencing
Limited access highways often require fencing or other forms of controlling access. Shared-use
paths constructed within these corridors, such as shown in Exhibit 1515-13, likely require
fencing. For guidance on fencing, limited access controls, and right of way, refer to Division 5 of
the Design Manual. Evaluate the impacts of fencing on sight distances.

Exhibit 1515 - 13 Shared-Use Path in Limited Access Corridor

1515.06(2) Restriction of Motor Vehicle Traffic

Shared-use paths often need some form of physical barrier at roadway intersections to prevent
unauthorized motor vehicles from entering.

Bollards have been used by many path owners to prevent unauthorized vehicle access.
However, bollards should not be applied indiscriminately, and there are other considerations to
bollard installation.

1515.06(2)(a) Landscaped Islands

A preferred method of restricting entry of motor vehicles is to split the entry way into two
sections separated by low landscaping, thereby splitting a path into two channels at roadway
intersections. This method essentially creates an island in the middle of the path rather than
installing a bollard. Such an island could be planted with low-growing, hardy vegetation capable
of withstanding the occasional authorized vehicle traveling over it. When splitting a path,
employ MUTCD pavement markings and signing, such as is used for bollards and obstructions.

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1515.06(2)(b) Bollard Considerations

Typically, one bollard located in the center of the path is sufficient to control motor vehicle
access to the path. If more than one bollard is needed, the additional bollards should be placed
at the edge of the shared-use path.

Install bollards at entrances to shared-use paths to discourage motor vehicles from entering. Do
not use bollards to divert or slow path traffic. When locating such installations, stripe an
envelope around the bollards and paint and reflectorize them to be visible to path users both
day and night. Bollards located on or adjacent to shared-use paths represent an object that
needs to be avoided by bicyclists and pedestrians. To increase the potential for appropriate
maneuvering to occur, provide designs where the post is clearly visible and recognizable.

When designing bollards, the following apply:

 The desirable design is to provide a single bollard, installed in the middle of the path
to reduce confusion.
 When multiple bollard posts are used in wide path sections, use a minimum 5-foot
spacing between the edge of concrete footings to permit passage of bicycle-towed
trailers, wheelchairs, and adult tricycles, with room for bicycle passage without
dismounting.
 Provide 4 feet minimum (5 feet desirable) clear width between the edge of concrete
footing and edge of path.
 At a minimum, provide stopping sight distance to bollards. An ideal location
for bollard placement is in a relatively straight area of the path where the post
placement has the stopping sight distance given in Exhibit 1515-14a and 14b. Do not
place bollards in difficult-to-see locations (for example, immediately upon entering a
tunnel).
 For cases where multiple posts are used longitudinally along the path, locate them
at least 20 feet apart, with the first post in line from each direction having stopping
sight distance.
 Use a contrasting striping pattern on the post.
 Use reflective materials on the post, such as a band at the top and at the base.
 Design all bollards along a corridor to be uniform in appearance. Frequent cyclists
can become familiar with the posts and recognize them easily.
 Provide pavement markings in accordance with the Standard Plans and MUTCD at all
bollards on paved paths.
 Use removable bollards (Bollard Type 1) to permit access by emergency and service
vehicles.
 Non-removable bollards (Bollard Type 2) may be used where access is not needed.

Refer to the Standard Plans for bollard designs and the Standard Plans and MUTCD for pavement
markings at bollards.

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Chapter 1515 Shared-Use Paths

When bollards need to be placed near the roadway, see Chapter 1600 for clear zone
requirements.

1515.07 Documentation
For the list of documents required to be preserved in the Design Documentation Package and
the Project File, see the Design Documentation Checklist:
 www.wsdot.wa.gov/design/projectdev/
Exhibit 1515 - 14a Stopping Sight Distance for Downgrades
Grade, G (%)

Stopping Sight Distance, S (ft)

(Based on 2.5 second reaction time)
Note:
Shaded area represents grades greater than 5%.

2
V
S   3.67V

0.30 f  G 
Where:
S = Stopping sight distance (ft)
V = Speed (mph)
f = Coefficient of friction (use 16)
G = Grade (%)

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Exhibit 1515 – 14b Stopping Sight Distance for Upgrades

Grade, G (%)

Stopping Sight Distance, S (ft)

(Based on 2.5 second reaction time)

Note:
Shaded area represents grades greater than 5%.

2
V
S   3.67V

0.30 f  G 

Where:
S = Stopping sight distance (ft)
V = Speed (mph)
f = Coefficient of friction (use 16)
G = Grade (%)

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 Chapter 1515 Shared-Use Paths

Exhibit 1515 - 15 Minimum Lengths for Crest Vertical Curves

A Stopping Sight Distance, S (ft)

(%) 40 60 80 100 120 140 160 180 200 220 240 260 280
2 3 3 3 3 3 3 3 3 3 3 30 70 110 150
3 3 3 3 3 3 3 20 60 100 140 180 220 260 300
4 3 3 3 3 15 55 95 135 175 215 256 300 348 400
5 3 3 3 20 60 100 140 180 222 269 320 376 436 500
6 3 3 10 50 90 130 171 216 267 323 384 451 523 600
7 3 3 31 71 111 152 199 252 311 376 448 526 610 700
8 3 8 48 88 128 174 228 288 356 430 512 601 697 800
9 3 20 60 100 144 196 256 324 400 484 576 676 784 900
10 3 30 70 111 160 218 284 360 444 538 640 751 871 1,000
11 3 38 78 122 176 240 313 396 489 592 704 826 958 1,100
12 5 45 85 133 192 261 341 432 533 645 768 901 1,045 1,200
13 11 51 92 144 208 283 370 468 578 699 832 976 1,132 1,300
14 16 56 100 156 224 305 398 504 622 753 896 1,052 1,220 1,400
15 20 60 107 167 240 327 427 540 667 807 960 1,127 1,307 1,500
16 24 64 114 178 256 348 455 576 711 860 1,024 1,202 1,394 1,600
17 27 68 121 189 272 370 484 612 756 914 1,088 1,277 1,481 1,700
18 30 72 128 200 288 392 512 648 800 968 1,152 1,352 1,568 1,800
19 33 76 135 211 304 414 540 684 844 1,022 1,216 1,427 1,655 1,900
20 35 80 142 222 320 436 569 720 889 1,076 1,280 1,502 1,742 2,000
21 37 84 149 233 336 457 597 756 933 1,129 1,344 1,577 1,829 2,100
22 39 88 156 244 352 479 626 792 978 1,183 1,408 1,652 1,916 2,200
23 41 92 164 256 368 501 654 828 1,022 1,237 1,472 1,728 2,004 2,300
24 43 96 171 267 384 523 683 864 1,067 1,291 1,536 1,803 2,091 2,400
25 44 100 178 278 400 544 711 900 1,111 1,344 1,600 1,878 2,178 2,500

Minimum Length of Vertical Curve, L (ft)

AS 2 Where:
L when S < L S = Stopping sight distance (ft)
900
A = Algebraic difference in grade (%)
L = Minimum vertical curve length (ft)
900
L  2S  when S > L Based on an eye height of 4.5 ft and an
A object height of 0 ft.

Note:
Below represents S ≤ L.
Shaded area represents A>10%.

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Sight distance (S)

Exhibit 1515 - 16 Lateral Clearance for
Horizontal Curves
Height of eye: 4.50 ft
Height of object: 0.0 ft M
Line of sight at the M distance is normally 2.3 ft above
centerline of inside lane at point of obstruction, Line of
provided no vertical curve is present in horizontal sight
curve. Obstruction or
ius
 S 28.65 
backslope Rad
M  R1  COS 
 R  Center of lane

R  1 R  M 
S COS   Where:
28.65   R  S = Sight distance (ft)
S ≤ Length of curve R = Centerline radius of inside lane (ft)
Angle is expressed in degrees. M = Distance from inside lane centerline (ft)

Stopping Sight Distance, S (ft)[1]

R (ft)
40 60 80 100 120 140 160 180 200 220 240 260 280 300
25 7.6 15.9
50 3.9 8.7 15.2 23.0 31.9 41.5
75 2.7 5.9 10.4 16.1 22.7 30.4 38.8 47.8 57.4 67.2
95 2.1 4.7 8.3 12.9 18.3 24.6 31.7 39.5 47.9 56.9 66.2 75.9 85.8
125 1.6 3.6 6.3 9.9 14.1 19.1 24.7 31.0 37.9 45.4 53.3 61.7 70.5 79.7
150 1.3 3.0 5.3 8.3 11.8 16.0 20.8 26.2 32.1 38.6 45.5 52.9 60.7 69.0
175 1.1 2.6 4.6 7.1 10.2 13.8 18.0 22.6 27.8 33.4 39.6 46.1 53.1 60.4
200 1.0 2.2 4.0 6.2 8.9 12.1 15.8 19.9 24.5 29.5 34.9 40.8 47.0 53.7
225 0.9 2.0 3.5 5.5 8.0 10.8 14.1 17.8 21.9 26.4 31.2 36.5 42.2 48.2
250 0.8 1.8 3.2 5.0 7.2 9.7 12.7 16.0 19.7 23.8 28.3 33.0 38.2 43.7
275 0.7 1.6 2.9 4.5 6.5 8.9 11.6 14.6 18.0 21.7 25.8 30.2 34.9 39.9
300 0.7 1.5 2.7 4.2 6.0 8.1 10.6 13.4 16.5 19.9 23.7 27.7 32.1 36.7
350 0.6 1.3 2.3 3.6 5.1 7.0 9.1 11.5 14.2 17.1 20.4 23.9 27.6 31.7
400 0.5 1.1 2.0 3.1 4.5 6.1 8.0 10.1 12.4 15.0 17.9 20.9 24.3 27.8
500 0.4 0.9 1.6 2.5 3.6 4.9 6.4 8.1 10.0 12.1 14.3 16.8 19.5 22.3
600 0.3 0.7 1.3 2.1 3.0 4.1 5.3 6.7 8.3 10.1 12.0 14.0 16.3 18.7
700 0.3 0.6 1.1 1.8 2.6 3.5 4.6 5.8 7.1 8.6 10.3 12.0 14.0 16.0
800 0.2 0.6 1.0 1.6 2.2 3.1 4.0 5.1 6.2 7.6 9.0 10.5 12.2 14.0
900 0.2 0.5 0.9 1.4 2.0 2.7 3.6 4.5 5.5 6.7 8.0 9.4 10.9 12.5
1,000 0.2 0.4 0.8 1.2 1.8 2.4 3.2 4.0 5.0 6.0 7.2 8.4 9.8 11.2

Minimum Lateral Clearance, M (ft)

Note:
[1] S is the sum of the distances (from Exhibits 1515-14a and 14b) for bicyclists traveling in both directions.

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Chapter 1520 Roadway Bicycle Facilities
1520.01 General
1520.02 Roadway Bicycle Facility Types
1520.03 Bicycle Facility Selection
1520.04 Intersection Design Treatments
1520.05 Additional Bicycle Design Requirements and Considerations
1520.06 Documentation
1520.07 References

1520.01 General
The Washington State Department of Transportation (WSDOT) encourages and relies on bicycle
use on and interconnecting with its facilities. Bicycle facilities or improvements for bicycle
transportation are included in WSDOT’s project development and highway programming
processes.

This chapter is a guide for designing bicycle facilities within state highway right of way or
between the curb lines on city streets designated as state highways. When designing facilities
outside of state highway right of way or beyond the curb on city streets designated as state
highways, use the local agency’s design guidance. If the bicycle facility will have shared use with
pedestrians incorporate ADA requirements in Chapter 1515.

Guidance in this chapter applies to typical situations encountered on state highways, and
includes options for intersection and interchange design. Unique design challenges are resolved
using expertise and guidance from the regional Bicycle Coordinator or if none exists, the WSDOT
headquarters Bicycle Coordinator. Additional concepts to resolve unique bicycle facility design
situations can be found in guides referenced (1520.07), but may require additional approvals for
signing, pavement markings or bike facility types not presented within this chapter.

The region Traffic Engineer is responsible for determining which sections are inappropriate for
bicycle traffic on state highways. The State Traffic Engineer, after consultation with the Bicycle
Advisory Committee, prohibits bicycling on sections of state highways through the traffic
regulation process. Contact the region Traffic Office for further information.

1520.02 Roadway Bicycle Facility Types

WSDOT has adopted the following six types of bicycle facilities, from most protected to least
protected:
 Shared-Use Paths (see Chapter 1515 for guidance)
 Raised and Curb-Separated
 Separated Buffered Bike Lanes
 Buffered Bike Lanes
 Conventional Bike Lanes
 Shared Lane Markings

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Shared-use paths (see Chapter 1515) are the most protected type of bike facility because the
path is physically separated from motor vehicle traffic most commonly by a wide vegetated
outer separation or other physical barrier. Roadway bicycle facilities can range from separated
from motor vehicle traffic to physically sharing a lane with motor vehicle traffic. The following
subsections discuss five types of roadway bicycle facilities adopted for use on state highways.

All roadway bicycle facility types will be designated by striping, signage, and pavement markings
to indicate the preferential or exclusive use for bicycle users. See 1520.05(1) for more
information.

1520.02(1) Raised and Curb-Separated

Exhibit 1520-1 shows a raised and curb-separated bicycle facility. These facilities are considered
protected because they are vertically separated from motor vehicle traffic. When a raised and
curb-separated bicycle facility is applied, it is considered part of the streetside zone (see Chapter
1230); however, it cannot be combined with other zone areas because the intent is also
segregation from pedestrians. The raised and curb-separated facility is dedicated for bike users
and delineated with pavement markings, signing, and in some cases pavement material.

There are advantages in utilizing streetside zones in conjunction with a raised and curb-
separated bike facility. A furnishing zone can be used to help segregate pedestrian and bicycle
users or for additional separation between the bike facility and motor vehicle traffic. If a
furnishing zone is not used to separate the raised bike facility from the pedestrian zone,
consider different pavement types, signs, pavement borders, or striping within the streetside
zone to effectively separate pedestrian and bicycle users.

When the raised and curb-separated bike facility is placed adjacent to motor vehicle traffic,
consider using a sloped and mountable curb (see Chapter 1230) to enable passing maneuvers
between cyclists.

Within incorporated limits, raised and curb-separated bike facilities are located behind the curb
and therefore fall under a local agency’s jurisdiction. (See Chapters 1230, and 1600 for
additional information on jurisdictional boundaries). In these situations, follow the local
agency’s design guidance for this type of bike facility.

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Exhibit 1520-1 Raised and Curb-Separated Bike Facility

1520.02(2) Separated Buffered Bike Lanes

Separated buffered bike lanes are at grade with the roadway, and they include a bike lane, a
buffer area, and some type of vertical feature that reduces the likelihood of encroachment into
the bike lane by motor vehicles and increases user comfort. Bike markings (see the Standard
Plans) in the bike lane and signage are employed. The most common type of vertical separator
used within the buffer area is a pavement mounted flexible tubular marker or delineator. Use of
dual-faced curbing, raised medians, or the parking zone adjoining the buffer area can also
accomplish the same task.

If parked vehicles within the parking zone are used as the vertical separator, the parking zone
cannot encroach onto the buffer area. When a separated buffered bike lane is positioned
between motor vehicle lanes and a parking zone, consider including an additional buffer area
between the parking zone and bike lane. Use of the buffer area described in these two
configurations facilitates loading and unloading of the parked vehicles, and reduces the risk of a

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cyclist being struck when a parked vehicle door opens (aka “dooring”). See NACTO’s Urban
Bikeway Design Guide and Urban Street Design Guide for examples.

Exhibit 1520-2 shows an example of separated buffered bike lane using a flexible tubular marker
as the vertical separator. A painted buffer strip with flexible tubular marker helps accentuate
the bicycle facility from the motor vehicle lane, when curbing or a raised median (also
considered vertical separation) is not used for the buffer strip. Consider a 3-foot-wide buffer
strip whenever possible. When utilizing a buffer, the bike lane itself may be 3 feet in width.
However, 5 feet is recommended exclusively to the bike lane to enable passing maneuvers
between cyclists, and account for the effective width needs of bicyclists when drainage features
are present in the bike lane. In space constrained areas where inexperienced bicyclists, such as
children, are expected or where there is a steep uphill grade use a 4 foot minimum for the
bicycle lane. High bicyclist volume locations should consider more width to facilitate mobility
performance for this mode. In constrained spaces where lower volumes of cyclists are
anticipated and inexperienced bicyclists are not expected, the minimum total width of both the
bike lane and buffer combined is 5 feet.
Exhibit 1520-2 Separated Buffered Bike Lane

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1520.02(3) Buffered Bike Lane

Exhibit 1520-3 shows a buffered bike lane. The design is effectively the same as a separated
buffered bike lane (see 1520.02(2)) without the use of vertical separators. Consider a 3-foot
buffer strip whenever possible. When utilizing a buffer, the bike lane itself may be 3 feet in
width, but it is recommended that 5 feet be provided exclusively to the bike lane to enable
passing maneuvers between cyclists. High cyclist volume locations should consider more width
to facilitate mobility performance for this mode. In locations where the posted speed is 30mph
or less and lower volumes of cyclists are anticipated, the minimum total width of both the bike
lane and buffer combined is 5 feet. In locations where inexperienced bicyclists, such as children,
are expected or when there is a steep uphill grade the minimum total width of both the bike
lane and the buffer combined is 6 feet.

Exhibit 1520-3 Buffered Bike Lane

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1520.02(4) Conventional Bike Lane

Conventional bike lanes are at grade and adjacent to motor vehicle traffic lane and are
designated by a single solid wide stripe between the motor vehicle lane and bike lane.
Additional bike markings (see the Standard Plans) in the bike lane and signage are employed. A
width of 6 feet is recommended for a conventional bike lane when designing for the “Interested,
but Concerned” user type. The minimum width for a conventional bike lane is 5 feet when
adjacent to curb, or 4 feet when no curb is present. Additional width is considered when higher
volumes of cyclists are anticipated or when adjacent to parallel on-street parking. Exhibit 1520-4
shows a conventional bike lane.

Exhibit 1520-4 Bike Lane

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1520.02(5) Shared Lane

A shared lane is a combined motor vehicle and bicycle lane, as shown in Exhibit 1520-5. Shared
lanes are appropriate for lower-speed and lower-volume streets. Shared lanes employ
pavement markings and signage to indicate the combined use. Shared lanes are more common
in bicycle boulevards, establishing a complete network for cyclists within an urban or suburban
environment. Shared lanes may be used on state highways within the ranges presented in
1520.03; however, it is more likely that shared lanes will interface with state highways through
crossing situations. It is important to consider how to configure an intersection or dedicated
bicycle crossing location when intersecting with a bicycle boulevard network (see 1520.04(5)).

Exhibit 1520-5 Shared Lane Markings

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Shared lane markings (aka “sharrows”) are pavement markings specifically used to indicate a
shared lane or intersection space. The position of the marking can encourage a desired lateral
position within the lane for cyclists, as well as alerting motor vehicle users. Consider the shared
lane marking placement with respect to on-street parking and the potential for dooring that will
lower safety performance for the cyclist. Shared lane markings must be placed at least 4 feet
from the face of curb, or in the center of the shared lane (or at least 11 feet from face of curb)
when an adjacent parallel parking zone is present.

Conventionally, wide lanes have been encouraged for shared-lane applications, to allow for
motor vehicles to pass cyclists, or for cyclists to pass motor vehicles in a queue. However, wider
lanes may also encourage motor vehicle drivers to travel at higher speeds and a detriment for a
shared lane application. Permitting in-lane passing between motor vehicles and bicyclists can
lower safety performance for cyclists.

The speed of cyclists can vary significantly between users, and depends on the experience,
fitness level of the user, bike technology, and roadway grade. If a shared lane is proposed on an
hill, consider a conventional bike lane in the upgrade direction of travel.
1520.02(5)(a) Accommodating Bikes on Shoulders

Many rural highways are used by bicyclists for commuting between cities or for recreation.
Providing and maintaining paved shoulders can significantly improve convenience and safety for
both bicyclists and motorists along such routes.

Accommodating bicycle users on the shoulder is common on state highways, particularly on

rural high-speed facilities. Shoulder improvements to facilitate bicycle travel include widening
the shoulders to a minimum of 4 feet, improving roadside maintenance (including periodic
sweeping), and removing surface obstacles such as drain grates that are not compatible with
bicycle tires. If shoulder rumble strips are present, provide for at least 4 feet of usable shoulder
between the rumble strip and the outside edge of shoulder. If guardrail or barrier is present,
increase the dimension to 5 feet of usable shoulder.

Accommodating bicycle use on shoulders is appropriate at many locations. Note, however, that
bike on shoulder accommodations are not dedicated bicycle facilities, and bicycle users do not
have the same operating privileges as with designated roadway bike facilities. In rural to
suburban/urban transition areas consider converting the shoulder to a protected buffered bike
lane, both to encourage speed management of motor vehicle users through the transition and
to establish a dedicated special-use lane for cyclists to tie into the local network.

1520.03 Bicycle Facility Selection

Bicycle facilities are desirable in order to provide viable travel alternatives, and for bicycle users
to have the ability to access land use destinations along state highways.

Understand how the state highway interfaces with routes identified as local, state, or regional
bike routes. If the state highway is the bike route, intersects with an existing route, or if bicycle
users are an identified modal priority (See Chapter 1103), account for the bike facility needs
within the design. Other projects need to consider a design that does not preclude the future
vision for a planned bike route, depending on the context identification selection (See Chapter
1102) and design year selection (See Chapter 1103).

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The only instance during planning or design when performance effects on existing or planned
bike facilities may not be considered is in locations being designed for the existing context, and
the location is prohibits bicycle use. State highways that prohibit bike use can be found here:
 http://www.wsdot.wa.gov/bike/closed.htm

1520.03(1) Types of Cyclists

Recent research indicates that people have different viewpoints and thresholds that dictate
their willingness to utilize bike facilities. Three general types of cyclist users exist:
 Strong and Fearless – This cyclist type are confident not only in their abilities as a cyclist
but also with their ability to operate intermixed with other modal users.
 Enthused and Confident – These cyclists prefer utilizing separated facilities, but are
comfortable riding intermixed within other modes in some transportation contexts.
 Interested, but Concerned – Cyclists who primarily have safety concerns and who are
less skilled or less familiar with the rules of the road, but would like to ride more. These
cyclists are frequently dissuaded from cycling, even if bike facilities are present,
because of the degree of separation between themselves and other traffic. This
category includes children and others new to bicycling.

1520.03(1)(a) Designing for the Interested, but Concerned

The Interested, but Concerned cyclist constitutes the largest segment of cyclist types within
suburban, urban and small town populations. Bike facility selection on state routes is based on
designing for the “Interested, but Concerned” user type as a starting point. Exhibit 1520-6a
shows ranges of applications for the different types of bicycle facilities related to generally
accepted safety and mobility performance for this design user.

Other performance needs may increase or decrease the viability of certain types of bike
facilities, such as shared-use paths through aesthetic areas or those planned for a mixture of
commute and recreational purposes. Further considerations for cyclist perception of comfort
are another factor that can affect use of the facility. Designing for a higher level of separation
may be more important at locations that serve community activity centers, schools or popular
destinations (such as a retail oriented segment of a route) where additional accommodations
are appropriate for either the functional uses or less skilled cyclists (including children). In these
situations, separated facilities or wider dimensions may provide the level of comfort needed to
satisfy user needs and context considerations. Additionally, some suburban, urban, and small
town contexts will have more specific bicycle performance needs that will help identify either
spot improvements or alteration of the type of existing facility to enhance a specific
performance area. Bike facility selection in 1520.03(1)(b) are provided for these reasons.

1520.03(1)(b) Designing for the Confident

In some contexts, it is appropriate to design for the Strong and Fearless, and Enthused and
Confident user types. In cases, where right of way is very constrained or where bicycles are
not considered the modal priority (see Chapter 1103), it is appropriate to use Exhibit 1520-
6b for determining facility selection after input from community engagement efforts.
However, understand that the application of Exhibit 1520-6b may result in less mode shift or
use of the capacity provided.

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Exhibit 1520-6a Bicycle Facility Selection Chart – Interested, but Concerned Cyclists

Note: Adapted from Montgomery County Bicycle Planning Guidance, Montgomery County Department of Transportation, 2014.

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Exhibit 1520-6b Bicycle Facility Selection Chart – Confident Cyclists

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1520.03(2) Speed Considerations

While Exhibits 1560-6a and 1560-6b provide ranges of speeds in which different types of bike
facilities may be appropriate, it is critical to understand that motor vehicle speed plays a
significant role in crash severity between motor vehicles and cyclists. When designing
multimodal facilities, a target speed selection within the low speed design control is
encouraged. Safety performance increases as motor vehicle speeds are decreased. The optimum
target speed for safety performance of multimodal designs is the lowest statutory speed
allowed on state routes, which is 25 mph. See Chapter 1103 for further discussion on target
speed and speed management treatments.

1520.04 Intersection Design Treatments

The principle objective when designing intersections for bicycle mobility and safety performance
is to provide a visible, distinct, predictable, and clearly designated path leading to and through
the intersection while managing potential conflicts between all other users and cyclists. This
chapter covers options for intersection design for bicyclists while chapters in the 1300 series
provide guidance for intersection control type selection and design.

Intersection design to meet the bicycle safety and mobility performance of the cyclist is unique
to each location. The primary emphasis is to create a visible, distinct, predictable and clear path
for the cyclist to reduce conflicts between cyclists and other design users. This is most
commonly achieved through clear delineation of the bike facility leading up to and through the
intersection, along with segregating or prioritizing movements between design users. Several
proven state-of-the-practice intersection treatments are presented within this section.
However, pavement marking or aspects about the configuration may not currently be supported
by the Manual on Uniform Traffic Control Devices.

At the time of publication, bike boxes (1520.04(2)) and two-stage left turn lanes (1520.04(3)) are
subject to an experimentation request to FHWA. Obtain Headquarters (HQ) Traffic Office
approval and assistance with submitting a request for experimentation. Consult, as appropriate,
the Federal Highway Administration’s (FHWA) MUTCD website for bicycle facilities for a listing of
the current status of bicycle-related pavement markings and treatments:
 http://www.fhwa.dot.gov/environment/bicycle_pedestrian/guidance/mutcd/index.cfm.
See 1520.05(1) for additional information on bicycle pavement markings under MUTCD
evaluation.

Note: Exhibits 1520-7 through 1520-9 all show colored pavement markings to increase the
safety performance of intersection designs. However, colored pavement markings are not
required, and may be added at a later stage if the desired safety performance is not met.

1520.04(1) Approach Through Lanes

The approach to intersections needs to balance the bicycle user’s safety needs with the mobility
needs of other users. Clear delineation of user lanes and potential conflict areas is currently the
treatment most commonly used to manage the approach to intersections. Use dotted lines to
identify the conflict area. Colored pavement markings can be used to further enhance and
delineate the conflict area. Exhibit 1520-7 shows different applications of the approach through
lane most likely to be encountered.

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1520.04(2) Bike Boxes and Crossing Pavement Markings

Bike boxes are designated areas for bicyclists positioned across and in front of the bike and
motor vehicle lanes as shown in Exhibit 1520-8. Bike boxes are used at signalized intersections
and increase both mobility and safety performance for the bicycle mode. Applying a bike box
assists mobility performance by prioritizing the bicycle movement at an intersection, and
enables a cyclist to position for a left-turn movement. Bike boxes have also been found to
prevent cyclist and motor vehicle encroachment into the pedestrian crossing, reducing conflicts
with pedestrians at intersections. Bicycle safety performance is improved by increasing the
visibility of the cyclist, and by reducing conflicts between motor vehicles making a right turn and
the bicycle through movement (also known as “right-hook” conflict).

There are several different ways to delineate bike lanes through the intersection. Dotted lines
are the most common, but can be combined with sharrows or green pavement markings (see
1520.05(1)) to further enhance the bike facility’s presence and position within an intersection.

1520.04(3) Two-Stage Left Turns

Exhibit 1520-9 shows an example of a two-stage left-turn design for bicycle users. This design
utilizes a rectangular bike box to enable cyclist queueing at the crossroad signal phase. The
bicyclist passes partway through the intersection to access the bike box, and then waits for the
crossroad next signal phase to eliminate the bicyclist left turn movement. This treatment is has
best value at intersections with significant volumes of motor vehicle traffic or large volumes of
left-turn cyclists, or when separated or buffered roadway bicycle facilities are used on the
segment.

This treatment can increase safety performance by reducing conflicts between cyclists and other
users, segregating motor vehicle and bicycle users, and separating turning cyclists from through
cyclists.

The position of the queue box is a critical aspect of this intersection design. Depending on the
size and configuration of the intersection, it may present a modal performance trade-off
between bicycle mobility and safety versus motor vehicle mobility performance. Use turn
simulation software to verify the queue box is outside the crossroad left-turn path, or restrict
left turns at the crossroad to accommodate the queue box. Similarly, right turns may need to be
restricted for motor-vehicles approaching the queue box if motor vehicle right-turn lanes or
right-turn pockets are not present.

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Exhibit 1520-7 Approach Through Lanes

Notes:
 Not to scale and not all dimensions shown.
 See 1520.05(1)(a) for criteria when considering the use of green colored pavement markings.
 Consider both the speed of motorized vehicles and bicyclists when determining the length of weave and degree of taper for the bike lane.

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Exhibit 1520-8 Bike Box and Intersection Crossing Markings

Notes:
• This exhibit is intended to illustrate options for bike facilities through interchange areas, and not intended to represent recommended practice for any
other features including ADA criteria (See Chapter 1510 for ADA and pedestrian design).
• See 1520.05(1)(a) for criteria when considering the use of green colored pavement markings.

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Exhibit 1520-9 Two-Stage Left-Turn Queue Box

Notes:
• This exhibit is intended to illustrate options for bike facilities through interchange areas, and not intended to represent recommended practice for any
other features including ADA criteria (See Chapter 1510 for ADA and pedestrian design).
• Consider both the speed of motorized vehicles and bicyclists when determining the length of weave and degree of taper for the bike lane.
• See 1520.05(1)(a) for criteria when considering the use of green colored pavement markings.

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Exhibit 1520-10 Median Refuge Island for Cyclists

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1520.04(4) Traffic Signals Considerations

Consider bicycle needs and intersection geometry when timing the traffic signal cycle and when
selecting the method of detecting the presence of cyclists. Contact the regional Bicycle
Coordinator and region Traffic Engineer for assistance in determining the timing criteria. At a
minimum consider safety performance needs, projected bicycle volume, motor vehicle volume,
traffic delay, roadway grade and the types of bicyclists using the intersection that may require
more time to clear the intersection. Consider the installation of effective loop detectors or other
methods of detecting a bicycle within the bike lane (in advance of the intersection) and turn
lanes. Select detectors sensitive enough to detect bicycles, and use a bike detector symbol to
identify detector presence.

Push button actuators may also be used to facilitate movement of bicyclists through a signalized
intersection. However, requiring bicyclists to go out of their way to use push button actuators
may create motor vehicle driver confusion of the bicyclists intended path through the
intersection, as well as inconveniencing the bicyclist. If pushbutton actuators are used, consider
their position relative to the bike facility. Pushbutton actuators are more effective when the
bike facility is adjacent to the curb (curb extensions at intersections can create this
environment). Consider an additional push button actuator for the exclusive use of cyclists when
positioning of the actuator is in conflict with ADA design requirements (see Chapter 1510). For
additional guidance on signal design, see Chapter 1330.
1520.04(4)(a) Bike Signals

Intersections with separated bike lanes, other complex multimodal intersection treatments or
those with a specific baseline need to increase bicycle user safety performance may incorporate
a dedicated bike signal head with detection or actuation systems. Bike signal heads further
separate modal user movements at intersections, while also allowing for priority to cyclists at
intersections. Contact the region Traffic Engineer for approval for application of this treatment.

At the time of this publication, bike signal faces are subject to requirements of FHWA Interim
Approval for this treatment. For current status of the treatment and conditions of the Interim
Approval, if still applicable, see
 http://www.fhwa.dot.gov/environment/bicycle_pedestrian/guidance/mutcd/index.cfm

1520.04(5) Median Refuge Islands for Cyclists

Layered networks have the benefit of separating modes onto different facilities to either
enhance mobility or safety performance of active transportation modes. However, layered
networks do intersect and specific median treatments exist to manage the confluence of these
networks.

Median refuge islands provide a refuge for bicyclists to cross one direction of traffic at a time
while restricting motor-vehicle through movements on crossroads designated as primary bicycle
corridors or bike boulevards. The treatment minimizes impacts for bicyclists on the crossroad
while prohibiting motor vehicle left turn movements from the cross street to eliminate conflicts.

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Consider median refuge islands when one or more of the following occurs:
 Bike facilities cross a roadway with median restricted left turns.
 Bike facilities cross a moderate to high (motor vehicle) volume roadway, with
intermediate motor-vehicle speeds
 Bike facilities cross a 4 lane divided highway.
 Separated or buffered bike facilities used on the cross street.
 There is a performance need to restrict motor vehicle through traffic on a bike route.
 Safety or mobility performance need of mainline cyclists exist for left turning
movements onto a bike route or shared use pathway

Exhibit 1520-10 shows an example of a median refuge designed for cyclists. Design refuge areas
between 4 and 5 feet wide (longitudinally with respect to the median), additional width may be
needed if high volumes of cyclists exist or are anticipated at the crossing. Consider the types of
cyclists and destinations when determining the median refuge length (lateral dimension with
respect to the median) to adequately store the bicycle. Consider what locations may need to
accommodate the length of a bicycle and trailer. The refuge area is to be in alignment with the
approach and receiving lanes of the crossroad. In other situations the median refuge island may
be designed for both pedestrians and bicycle users. When this is the case, design the median
refuge predominately for the pedestrian as with midblock crossings (See Chapter 1510), note
that additional lateral and longitudinal dimensions will be necessary.

1520.05 Additional Bicycle Design Requirements and Considerations

1520.05(1) Signing and Pavement Markings

Use the MUTCD and the Standard Plans for signing and pavement marking criteria. (See Chapter
1020 for additional information on signing and Chapter 1030 for information on pavement
markings). Pavement marking and signing options for bicycle facilities are rapidly changing.
Situations may exist where unique project concerns may necessitate innovative pavement
markings or signage. Consult, as appropriate, the Federal Highway Administration (FHWA)
MUTCD website for bicycle facilities for a listing of the current status of bicycle-related
pavement markings and treatments:
 http://www.fhwa.dot.gov/environment/bicycle_pedestrian/guidance/mutcd/index.cfm

HQ Traffic Office approval is necessary for traffic control devices not currently approved for use
through the MUTCD.

1520.05(1)(a) Green Pavement Marking – Criteria for Consideration

Green -colored pavement markings are a traffic control device whose need must be
demonstrated before use and documented with a design decision. The highest benefit of
applying green colored pavement markings occurs where the potential conflicts exist between
cyclists and other design users, or when other design users should yield to cyclists. Green
colored pavement markings are only intended as a supplemental treatment for standard striping
configurations for bicycle facilities.

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The below criteria are provided when evaluating the need to apply green colored pavement
markings.

1. Existing Bike Facilities – retrofitting an existing facility with green pavement may be
considered when two or more of the following apply:
a. It is the engineering judgment of the Region Traffic Engineer
b. There is an existing traffic conflict area, such as bike lane crossing a motor vehicle
turn lane, and there are one or more observed motor vehicle and bicyclist crashes in
the last 5 years.
c. The bike mode is a modal priority (see Chapter 1103), and there is a baseline or
contextual need identified associated with increasing safety performance of the
mode.
d. When a bike route intersects a multilane highway, and the crossing is neither
signalized nor a roundabout.

2. Changing of Bike Facility Type –consider green pavement markings when one or more of the
following apply:
a. It is the engineering judgment of the Region Traffic Engineer.
b. A transition from a separated facility through a functional intersection or
interchange area necessitates additional delineation to create a clear, visible,
predictable and distinct travel path for bike users, and a bike signal or actuation
device is not used.
c. The facility type change does not substantively alter the configuration of an existing
conflict area, and there are one or more observed motor vehicle and bicyclist
crashes in the last 5 years at that conflict area.

3. New Bike Facility – Generally, the immediate application of green colored pavement on a
new bike facility is discouraged until the need for increased safety performance is
demonstrated. This said, consider green colored pavement when two or more of the
following conditions exist:
a. It is the engineering judgment of the Region Traffic Engineer
b. The bike mode is a modal priority (see Chapter 1103), and there is a baseline or
contextual need in which the application of green colored pavement markings is
needed to meet the stated modal safety performance target (see Chapter 1101).
c. The bike facility nodes and/or crossings are within 1 mile of activity centers, such as
schools, libraries, colleges, etc.
d. The bike facility crosses a motor vehicle free right turn to or from an interchange
ramp.
e. The bike facility is a bike route or bike boulevard (for definition, see NACTO’s Urban
Bikeway Design Guide).
f. The state route is also a city street, and the city policy or municipal code requires
green colored pavement markings as their standard.
g. The bike facility is raised and curb separated, and the city engineer requests green
colored pavement markings at either crossings or conflict areas.

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1520.05(1)(b) Green Pavement Marking – Configuration

Use green pavement markings to supplement the conventional white bike lane striping as
required by the MUTCD. Apply green colored pavement markings in conflict areas, consistent
with what is shown in Exhibits 1520-7 through 1520-9. Preceding the conflict area, apply solid
green 25-50 feet in length (see Exhibit 1520-11), use green ladder striping between the required
white dotted striping through the extent of the conflict area, and apply solid green after the
ladder striping for at least 25 ft but no more than 50 ft. If closely spaced conflict areas exist, it
may be appropriate to carry solid green into the next conflict area as determined by the Region
Traffic Engineer.
1520-11 Length of Solid Green Pavement Marking Preceding Conflict Area

Motor Vehicle Length of Solid Green Colored Pavement

Speed Marking Preceding Conflict Area
25 mph 25 ft

30 mph 30 ft

35 mph or more 35-50 ft

Interchange
See 1520.05(6)
Ramps

Additional configurations or styles exist for the application of green colored pavement and can
be used with the approval of HQ Traffic Office. Consider specifically when bike route continuity
with a local agency’s bike facilities is a concern.

1520.05(2) Drainage Grates and Manhole Covers

Locate drainage inlet grates and manhole covers to avoid bike lanes. When drainage grates or
manhole covers are located in a bike lane, minimize the effect on bicyclists. Consider providing 3
feet of lateral clearance between the edge of a drainage inlet grate and the bike lane stripe,
when practicable. Install and maintain grates and manhole covers level with the surface of the
bike lane.

Provide drainage inlet grates on bicycle facilities that have openings narrow enough and short
enough that bicycle tires will not drop into the grates. Replace existing grates that are not
designed for bicycles: a WSDOT vanned grate, herringbone grate, or other grate with an opening
4 inches or less center to center and perpendicular to the direction of travel.

1520.05(3) At-Grade Railroad Crossings

Whenever a bike lane crosses railroad tracks, continue the crossing at least as wide as the bike
lane. Use special construction and materials to keep the flangeway depth and width to a
minimum. Wherever possible, design the crossing at right angles to the rails. Where a skew is
unavoidable, widen the shoulder or bike lane, to permit bicyclists to cross at right angles. Exhibit
1520-12 shows options and details to consider for at-grade railroad crossings.

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Exhibit 1520-12 At-Grade Railroad Crossings

Direction of
bicycle travel

c ks
Bikeway Tra
RR
Large radii desirable
Striped
Widen to permit right
angle crossing

Bikeway
R a il
ro a d

Shoulder
14 ft
R/W

max Widened Shoulder

45°

Additional R/W
required
Bikeway

Curve
widening

Curve
widening
Additional R/W
required
R a ilr
Highway R/W

R a ilr

oad
oad

R/W
R/W

Bikeway
Bikeway
Shoulder
Shoulder

45o Crossing 90o Crossing

(acceptable) (most desirable)

Notes:
 Provide additional width at railroad crossings to allow bicyclists to choose their own crossing routes.
 When pedestrians are provided for, design as a shared-use path (see Chapters 1510 and 1515).

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1520.05(4) Barrier and Railing

When the edge of the bike lane is within 5 feet of a barrier or railing, provide a barrier height a
of 42 inches or more to reduce the potential for bicyclists to fall over the barrier (see Exhibit
1520-13). When the bicycle facility is adjacent to barrier, consider single slope barrier to
mitigate for pedal movement conflicts other barrier designs.

On structures, the bridge railing type and height are part of the structure design. Contact the HQ
Bridge and Structures Office for additional information. (See Chapter 720 for further
considerations.)
Exhibit 1520-13 Barrier Adjacent to Bicycle Facilities

Bike lane
42" [1][2]
Edge of
traveled way

Bike Lane

Bike lane between edge of traveled way and barrier

Edge of
traveled way

Bike Lane With Sidewalk or Curb

Bike lane between edge of traveled way and sidewalk

Notes:

[1] Height does not apply to bridge railing. On structures, the bridge railing type and height are part of
the structure design. (Contact the HQ Bridge and Structures Office for additional information.)
[2] Applies to bike lanes. Additional height is not needed for shared-use roadways.

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1520.05(5) Transit Considerations

Transit and bicycle facilities can generate unique conflicts because of their typical position
within the geometric cross section of the traveled way zone. Where public transport and cycling
facilities meet, an integrated design that does not inconvenience either mode is desirable to
meet the performance needs of these modes. Consider the following:
 Route the bike lane behind the transit stop location using a raised bike lane or outer
separation for that spot location. Ensure the resulting outer separation provided for
the transit stop meets the Americans with Disabilities Act (ADA) requirements (see
Chapter 1510). Ensure signing and pavement markings are used to alert cyclists and
pedestrians of the conflict area created with this design.
 Provide additional delineation in the bike lane to highlight the pedestrian and cyclist
conflict, when separated buffered bike lanes and in-lane transit stops are used. Bus
loading and other conflict areas will need to meet ADA requirements (see Chapter
1510) and those of the transit agency.
 Where bus operating speeds are low, consider a bus-bicycle shared lane with the
transit agency.

Consider providing bicycle parking facilities near public transportation stops to improve
accessibility performance needs.

1520.05(6) Interchange Considerations

Crossing bicycle facilities through an interchange functional area has a greater potential for
conflict because of higher travel speeds and lane configurations. Interchange crossings designed
in a manner similar to intersection crossings are more compatible to bicyclists. Exhibits 1520-
14a through 1520-14d illustrate design options for bike facilities design through an interchange
functional area. Interchanges can be special environments to evaluate the safety and mobility
needs of the bike mode. The specific challenge is often the inclusion of motor vehicle free right
turns to or from interchange ramps. The preferred configuration for bicycle safety performance
at an interchange will not provide the motor vehicle free right turn, and will realign ramps to
intersect perpendicular with the crossroad (see off ramp terminal in Exhibit 1520-14a).
However, given the modal priorities and operational performance needs of those priorities, this
configuration may not always be practicable.

In some cases, it is possible to align the bike facility to cross an off ramp with a more direct path
for the bike crossing (see Exhibit 1520-14d). Breaking up the work load for the motor vehicle
driver is one advantage of this configuration, similar to pedestrian treatments common in
roundabout design. Shortening the crossing distance required for the bicyclist is another
advantage with this configuration. Consider the inclusion of Rectangular Rapid Flashing Beacons
(RRFB) or a refuge island when there are multiple travel lanes. This configuration may also
require additional speed management (see Chapter 1103), signing or striping treatments on the
ramp.

Other situations may dictate additional delineation parallel to and matching the length of the
auxiliary lane provided at the ramp terminal as shown in Exhibit 1520-14b. This configuration
can be coupled with additional signing preceding the motor vehicle merge, and additional
separation or a buffer between the ramp’s auxiliary lane and the through bike lane. The length
of the motorized auxiliary lane will vary depending on speed and volume, so the length of green

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markings shown in Exhibit 1520-11 may not adequately satisfy the delineation desired at these
locations. Consult with the Region Traffic Engineer for determining the length of green
pavement markings at interchange locations, when they are provided according to
1520.05(1)(a).

Exhibit 1520-14c provides a design option in which the bike lane merges with the sidewalk, and
requires bicyclists to cross an interchange ramp at the pedestrian crossing. This configuration is
ideal when bicycle mode is not identified as a modal priority, there is high motor vehicle ADT,
there is a large intersection design vehicle, there is intermediate to high motor vehicle speeds,
or when there are identification design users (see Chapter 1103) that suggests low experienced
bicyclists will be present. Consider inclusion of an RRFB or a median refuge island when there
are multiple lanes. Exhibits 1520-14b and 1520-14d also show the option of providing a bike
ramp to the sidewalk. Providing options for cyclists at interchanges is encouraged, since the
range of comfort among users is known to be diverse. Consult with the local agency regarding
any prohibitions against bicyclists using the sidewalk that may negate the ability to implement
this configuration.

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Exhibit 1520-14a – Bike Facility Crossing On and Off Ramps

Notes:
• Adapted from the Draft Recommended Design Guidelines to Accommodate Pedestrians and Bicycles at Interchanges, ITE, unpublished.
• This exhibit is intended to illustrate options for bike facilities through interchange areas, and not intended to represent recommended practice for any other features including ADA criteria (See Chapter 1510 for ADA and pedestrian
design).

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Exhibit 1520-14b – Bicycle Facility Crossing Single Lane On Ramp

Notes:
• Adapted from the Draft Recommended Design Guidelines to Accommodate Pedestrians and Bicycles at Interchanges, ITE, unpublished.
• This exhibit is intended to illustrate options for bike facilities through interchange areas, and not intended to represent recommended practice for any other features including ADA criteria (See Chapter 1510 for ADA and pedestrian
design).
• Consider both the speed of motorized vehicles and bicyclists when determining the length of weave and degree of taper for the bike lane.

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Exhibit 1520-14c – Bicycle Facility Crossing Option for Dual Lane On-Ramp Configuration

Notes:
• Adapted from the Draft Recommended Design Guidelines to Accommodate Pedestrians and Bicycles at Interchanges, ITE, unpublished.
• This exhibit is intended to illustrate options for bike facilities through interchange areas, and not intended to represent recommended practice for any other features including ADA criteria (See Chapter 1510 for ADA and pedestrian
design).

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Exhibit 1520-14d – Bicycle Facility Crossing Option for Dual Off-Ramp

Notes:
• Adapted from the Draft Recommended Design Guidelines to Accommodate Pedestrians and Bicycles at Interchanges, ITE, unpublished
• This exhibit is intended to illustrate options for bike facilities through interchange areas, and not intended to represent recommended practice for any other features including ADA criteria (See Chapter 1510 for ADA and pedestrian
design).

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1520.05(7) Sight Triangles at Intersections and Conflict Areas

The visibility of all users is to be evaluated at intersections. Identifying sight triangles can help
determine the optimal configuration of bicycle and pedestrian crossings. See Chapter 1310 for
determining sight distance at an intersection, and Chapter 1340 for sight distance at road
approaches near midblock crossings. Visibility is impacted by both speed and the configuration
of the intersection. There are multiple benefits in multimodal intersection configurations to
proactively manage motorized vehicle speeds (see Chapter 1103 for speed reducing traffic
calming treatments) at intersection locations, rather than widening the intersection and/or
removing elements from the roadside or streetside zone to obtain the needed sight distance.
The primary objective at intersections and interchanges is to create a clear, distinct, and
predictable travel path for all users through the intersection.

1520.05(8) Maintenance Considerations

Consult with all maintenance jurisdictions for partnering opportunities and clearly understand
which jurisdiction will be responsible for specific elements of the bike facility maintenance.
Some maintenance jurisdictions may be better equipped to maintain the bike facility than
others. Certain bike facilities, like the raised and curb separated, clearly fall within the
jurisdictional authority of an incorporated city (see chapters 1230 and 1600 for more
information). For other facility types it may be more advantageous to discuss the capabilities of
each maintenance jurisdiction, and develop a maintenance agreement (see Chapter 301).

It is important to obtain information from maintenance regarding the facility type and
dimensioning, and discuss methods for maintaining the facility. The Maintenance Owner’s
Manual (See Chapter 301) is suggested to contain frequency, equipment needs and material
types necessary for the continual maintenance of facility features, including but not limited to:
 Sweeping
 Snow removal
 Striping and pavement markings
 Signing

1520.06 Documentation
Document the type of bike facility employed or changed in section 5 of the Basis of Design.
Dimensions chosen for the facility are documented on design parameter sheets.

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1520.07 References

1520.07(1) Federal/State Laws and Codes

Americans with Disabilities Act of 1990 (ADA)

23 Code of Federal Regulations (CFR) Part 652, Pedestrian and Bicycle Accommodations and
Projects

Revised Code of Washington (RCW), Chapter 35.75, Streets – Bicycles – Paths

 http://apps.leg.wa.gov/rcw/default.aspx?cite=35.75

RCW 46.04, Definitions

 http://apps.leg.wa.gov/rcw/default.aspx?cite=46.04

RCW 46.61, Rules of the road

 http://apps.leg.wa.gov/rcw/default.aspx?cite=46.61\

RCW 46.61.710, Mopeds, electric-assisted bicycles – General requirements and operation

 http://apps.leg.wa.gov/rcw/default.aspx?cite=46.61.710

RCW 47.26.300, Bicycle routes – Legislative declaration

 http://apps.leg.wa.gov/rcw/default.aspx?cite=47.26.300

1520.07(2) Supporting Information

Urban Bikeway Design Guide, NACTO, current edition (WSDOT endorsed)
 http://nacto.org/publication/urban-bikeway-design-guide/

Guide for the Development of Bicycle Facilities, AASHTO, current edition

 https://bookstore.transportation.org/collection_detail.aspx?ID=116

Separated Bike Lane Planning and Design Guide, FHWA, current edition
 http://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/separated_bikelane
_pdg/page00.cfm

Bicycle Parking Guidelines, Association of Pedestrian and Bicycle Professionals, current edition
 http://www.apbp.org/?page=Publications

Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA; as adopted
and modified by Chapter 468-95 WAC “Manual on uniform traffic control devices for streets and
highways” (MUTCD)
 www.wsdot.wa.gov/publications/manuals/mutcd.htm

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT
 www.wsdot.wa.gov/publications/manuals/m21-01.htm

Understanding Flexibility in Transportation Design – Washington, WSDOT, 2005

 www.wsdot.wa.gov/research/reports/600/638.1.htm

Selecting Roadway Design Treatments to Accommodate Bicycles, USDOT, Federal Highway

Administration (FHWA), 1994

WSDOT Design Manual M 22-01.12 Page 1520-31

November 2015
Roadway Bicycle Facilities Chapter 1520

NCHRP Report 766: Recommended Bicycle Lane Widths for Various Roadway Characteristics,
Transportation Research Board of the National Academies, 2014
 http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_766.pdf

NCHRP Report 500 Volume 18: A Guide for Reducing Collisions Involving Bicycles, Transportation
Research Board of the National Academies, 2006
 http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_500v18.pdf

Four Types of Cyclists?, Dill, Jennifer, and Nathan McNeil, Transportation Research Record:
Journal of the Transportation Research Board 2387.1 (2013): 129-138.

Recommended Design Guidelines to Accommodate Pedestrians and Bicycles at Interchanges, ITE,

unpublished.
 http://ecommerce.ite.org/IMIS/ItemDetail?iProductCode=RP-039

Montgomery County Bicycle Planning Guidance, Montgomery County Department of

Transportation, 2014.
 http://www.montgomeryplanning.org/transportation/bikeways/documents/FINALBicyclePla
nningGuidance.pdf

Separated Bike Lane Planning and Design Guide, Massachusetts Department of Transportation
(MassDOT), 2015
 http://www.massdot.state.ma.us/highway/DoingBusinessWithUs/ManualsPublicationsForms
/SeparatedBikeLanePlanningDesignGuide.aspx

Page 1520-32 WSDOT Design Manual M 22-01.12

November 2015
Chapter 1600 Roadside Safety
1600.01 General
1600.02 Clear Zone
1600.03 Mitigation Guidance
1600.04 Medians
1600.05 Other Roadside Safety Features
1600.06 Documentation
1600.07 References

1600.01 General
Roadside safety addresses the area outside the roadway and is an important component of total
highway design. There are numerous reasons why a vehicle leaves the roadway, including driver
error and behaviors. Regardless of the reason, a roadside design can reduce the severity and
subsequent consequences of a roadside encroachment. From a crash reduction and severity
perspective, the ideal highway has roadsides and median areas that are relatively flat and
unobstructed by objects. It is also recognized that different facilities have different needs and
considerations, and these issues are considered in any final design.

It is not possible to provide a clear zone free of objects at all locations and under all
circumstances. The engineer faces many tradeoffs in design decision-making, balancing needs of
the environment, right of way, and various modes of transportation. The fact that
recommended design values related to the installation of barrier and other mitigation
countermeasures are presented in this chapter, does not mean that WSDOT is required to
modify or upgrade existing locations to meet current criteria.

Roadside safety may be addressed by projects identified through priority programming, during
certain preservation project activities (See Chapter 1120), or may be considered by projects as
part of a safety analysis (See Chapter 321). Elements such as sideslopes, fixed objects, and water
are all features that a vehicle might encounter when it leaves the roadway and become part of
such an analysis.

On projects where the need to mitigate objects is determined based on location related to
Design Clear Zone, consider the following mitigation measures in this order: (See 1600.02 Clear
Zone)
1. Remove
2. Relocate
3. Redesign a fixed object by using breakaway features or making the fixed object traversable
(See Section 1600.03)
4. Shield with a traffic barrier
5. Delineate (To only delineate requires a Design Analysis. If this seems to be your only option,
consult your Region traffic barrier expert or your Region’s ASDE.)

Factors for selecting a mitigation measure include, but may not be limited to:
 Crash severity potential
 Maintenance needs
 Cost (initial and life cycle costs)

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Roadside Safety Chapter 1600

Rumble strips can be employed to reduce the potential for lane departure or roadside
encroachment in certain contexts (see Section 1600.05(1)). Use traffic barriers when other
measures cannot reasonably be accomplished and conditions are appropriate based on an
engineering analysis (See Chapter 1610).

1600.02 Clear Zone

A clear roadside border area is a primary consideration when analyzing roadside and median
features (as defined in Section 1600.03). The intent is to provide as much clear, traversable area
for a motorist to recover as practicable given the function and context of the roadway and the
potential tradeoffs. The Design Clear Zone is used to evaluate the adequacy of the existing clear
area and proposed modifications of the roadside. When considering the placement of new
objects along the roadside or median, evaluate the potential for impacts and try to select
locations with the least likelihood of an impact by an errant motorist.

In situations where the Design Clear Zone is beyond WSDOT right of way, evaluate options on a
case-by-case basis. Consider the nature of the objects within the Design Clear Zone, the roadway
geometry, traffic volume, and crash history. Coordinate with adjacent property owners when
proposed options include any work beyond WSDOT right of way. At a minimum, provide clear
zone to the limits of the WSDOT right of way.

Clear zone is measured from the edge of the through traveled way. All projects that alter the
relationship between the through lane and the roadside by widening or realignment have
altered the existing clear zone, and require an evaluation of objects in the clear zone. Auxiliary
lanes longer than 400 feet generally operate the same as a through lane and should be
considered through lanes for the purpose of determining Design Clear Zone.

1600.02(1) Design Clear Zone along Limited Access State Highways and
Other State Highways Outside Incorporated Cities and Towns
Use the Design Clear Zone Inventory form (Exhibit 1600-3) to identify features to be mitigated
and propose actions taken to address those features.

Guidance for establishing the Design Clear Zone for highways outside incorporated cities is
provided in Exhibit 1600-2. This guidance also applies to limited access facilities within the city
limits. Providing a clear recovery area that is consistent with this guidance does not require any
additional documentation. However, there might be situations where it is not practicable to
provide these recommended distances. In these situations, document the decision as a Design
Analysis as discussed in Chapter 300.

There is flexibility in establishing the Design Clear Zone in urbanized or urbanizing areas where
operating speeds are 35 mph or less. To achieve this flexibility, use a Design Analysis to establish
the Design Clear Zone that presents the tradeoffs associated with the decision. Provide
information on the benefits and effects of the Design Clear Zone selected in the Design Analysis,
including safety, aesthetics, the environment, economics, modal needs, and access control.
Although not a WSDOT policy document on clear zone, Chapter 10 of the AASHTO Roadside
Design Guide provides information to consider when performing a Design Analysis in urbanized
areas.

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Chapter 1600 Roadside Safety

In curbed sections, and where applicable (e.g. parking), provide an 18-inch operational offset
beyond the face of curb for lateral clearance to accommodate opening car doors or large side
mirrors.

1600.02(2) Design Clear Zone Inside Incorporated Cities and Towns

For managed access state highways within an urban area, it might not be practicable or
appropriate to provide the Design Clear Zone distances shown in Exhibit 1600-2. Roadways
within an urban area generally have curbs and sidewalks and might have objects such as trees,
poles, benches, trash cans, landscaping, and transit shelters along the roadside.

For projects on city streets as state highways that include work in those areas that are the city’s
responsibility and jurisdiction (see Exhibit 1600-1), design the project using the city’s develop-
ment/design standards. The standards adopted by the city must meet the requirements set by
the City Design Standards Committee for all arterial projects, bike projects, and federal-aid
projects. See the Local Agency Guidelines, Chapter 42, for more information on this Committee.

Exhibit 1600-1 City and State Responsibilities and Jurisdictions

City Extent of State City Extent of State City

Responsibility/ Responsibility/ Responsibility/ Responsibility/ Responsibility/
Jurisdiction Jurisdiction Jurisdiction Jurisdiction Jurisdiction

Roadway Surface / Roadway Surface /

Median
Traveled Way Traveled Way

CL Auxiliary Lane
R/W R/W
or Bus Pullout

Curb & Gutter (typ.)

Roadway with Raised Median

(Landscaped)

1600.02(2)(a) Roadside and Median

For managed access state highways inside incorporated cities, it is the city’s responsibility to
establish an appropriate Design Clear Zone in accordance with guidance contained in the City
and County Design Standards (Local Agency Guidelines, Chapter 42.) Exhibit 1600-1 shows an
example of state and city responsibilities and jurisdictions. Document the Design Clear Zone
established by the city in the Design Documentation Package. Have the responsible
transportation official from the city (e.g., City Engineer) document the Design Clear Zone, and
their acknowledgement and acceptance of the design and maintenance responsibilities for
project roadsides and medians, in a letter addressed to WSDOT, and file this letter as part of the
local agency coordination in the Design Documentation Package. Respond to the sender
acknowledging receipt.

1600.02(3) Design Clear Zone and Calculations

Use Exhibit 1600-2 to determine the Design Clear Zone based on posted speed, sideslopes, and
traffic volume at any given location. Note that there are no clear zones distances in the table for
3H:1V fill slopes. Although fill slopes between 4H:1V and 3H:1V are considered traversable if

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Roadside Safety Chapter 1600

free of fixed objects, these slopes are defined as nonrecoverable slopes. A vehicle might be able
to begin recovery on the shoulder, but likely will not be able to further this recovery until
reaching a flatter area (4H:1V or flatter) at the toe of the slope. Under these conditions, the
Design Clear Zone distance is called a recovery area. The method used to calculate the recovery
area and an example are shown in Exhibit 1600-4.

For ditch sections, the following criteria determine the Design Clear Zone:

(a) For ditch sections with foreslopes 4H:1V or flatter (see Exhibit 1600-5, Case 1, for an
example), the Design Clear Zone distance is the greater of the following:
 The Design Clear Zone distance for a 10H:1V cut section based on speed and the
average daily traffic (ADT); or
 A horizontal distance of 5 feet beyond the beginning of the backslope.

When a backslope steeper than 3H:1V continues for a horizontal distance of 5 feet beyond
the beginning of the backslope, it is not necessary to use the 10H:1V cut slope criteria.

(b) For ditch sections with foreslopes steeper than 4H:1V and backslopes steeper than 3H:1V,
the Design Clear Zone distance is 10 feet horizontal beyond the beginning of the backslope
(see Exhibit 1600-5, Case 2, for an example).

(c) For ditch sections with foreslopes steeper than 4H:1V and backslopes 3H:1V or flatter, the
Design Clear Zone distance is the distance established using the recovery area formula (see
Exhibit 1600-4; also see Exhibit 1600-5, Case 3, for an example).

1600.03 Mitigation Guidance

There are three general categories of features to be mitigated: sideslopes, fixed objects, and
water. This section provides guidance for determining when these objects are to be mitigated.
For each case, the following conditions need consideration:
 Locations with an expected elevated crash frequency.
 Locations with pedestrian and bicyclist usage (See Chapters 1510, Pedestrian Facilities,
1515, Shared-Use Paths, and 1520, Roadway Bicycle Facilities).
 Locations where speed management measures are present or contemplated (See
Chapter 1103).
 Locations with playgrounds, monuments, and other locations with high social value.
 Locations where redirectional landforms, also referred to as earth berms, were
installed to mitigate objects located in depressed medians and at roadsides. They were
constructed of materials that provided support for a traversing vehicle. With slopes in
the range of 2H:1V to 3H:1V, they were intended to redirect errant vehicles. The use of
redirectional landforms has been discontinued as a means for mitigating fixed objects.
Where redirectional landforms currently exist as mitigation for a fixed object, provide
designs where the landforms, and the feature(s) they were intended to mitigate, are
removed, relocated, made crashworthy, or shielded with barrier.

The use of a traffic barrier for features other than those described below requires justification.

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Chapter 1600 Roadside Safety

1600.03(1) Side Slopes

1600.03(1)(a) Fill Slopes

Fill slopes can increase the crash potential for an errant vehicle with the degree of severity
dependent upon the slope and height of the fill. Providing fill slopes that are 4H:1V or flatter can
mitigate this condition. If flattening the slope is not feasible or cost-effective, the installation of
a barrier might be appropriate. Exhibit 1600-6 represents a selection procedure used to
determine whether a fill sideslope constitutes a condition for which a barrier is a cost-effective
mitigation. The curves shown on Exhibit 1600-6 are based on the severity indexes and represent
the points where total costs associated with a traffic barrier are equal to the predicted cost of
crashes over the service life for selected slope heights without traffic barrier. If the ADT and
height of fill intersect on the “Barrier Recommended” side of the embankment slope curve, then
provide a barrier if flattening the slope is not feasible or cost-effective.

Do not use Exhibit 1600-6 for slope design. Design slopes consistent with guidance in Chapter
1239, evaluating designs with clear, traversable slopes before pursuing a barrier option. Also, if
Exhibit 1600-6 indicates that barrier is not recommended at a slope, that result is not
justification for a Design Analysis. For example, if the ADT is 4,000 and the embankment height
is 10 feet, barrier might be cost-effective for a 2H:1V slope, but not for a 2.5H:1V slope. This
process only addresses the crash potential on the slope. Objects on the slope can compound the
condition. Where barrier is not cost-effective, use the recovery area formula to evaluate fixed
objects on critical fill slopes less than 10 feet high.

1600.03(1)(b) Cut Slopes

A traversable cut slope reduces crash potential. The exception is a rock cut with a rough face
that might cause vehicle snagging rather than providing relatively smooth redirection.

Analyze the location and evaluate the roadside characteristics, crash potential, and other
benefits of treatment of rough rock cuts located within the Design Clear Zone. Conduct an
individual investigation for each rock cut or group of rock cuts. A cost-effectiveness analysis that
considers the consequences of doing nothing, removal, smoothing of the cut slope, grading at
the base of the rock cut to provide a smooth surface, and other viable options to reduce the
severity of the condition can be used to determine the appropriate treatment. Some potential
mitigative options are roadside barrier and rumble strips.

1600.03(2) Fixed Objects

Use engineering judgment when considering the following objects for mitigation:
 Wooden poles or posts with cross-sectional areas greater than 16 square inches that
do not have breakaway features.
 Signs, illumination, cameras, weather stations, and other items mounted on non-
breakaway poles, cantilevers, or bridges.
 Trees with a diameter of 4 inches or more, measured at 6 inches above the ground
surface.
 Fixed objects extending above the ground surface by more than 4 inches; for example,
boulders, concrete bridge rails, signal/electrical/ITS cabinets, piers, and retaining walls.
 Drainage elements, such as culvert and pipe ends.

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Roadside Safety Chapter 1600

1600.03(2)(a) Trees

When evaluating new plantings or existing trees in the Design Clear Zone, consider the
maximum allowable diameter of 4 inches, measured at 6 inches above the ground when the
tree has matured. When removing trees within the Design Clear Zone, complete removal of
stumps is preferred. However, to avoid significant disturbance of the roadside vegetation, larger
stumps may be mitigated by grinding or cutting them flush to the ground and grading around
them.

Removal of trees may reduce the severity of impacts of roadway departure. It is recognized that
different facilities have different needs and considerations, and these issues are considered in
any design. For instance, removal of trees within the Design Clear Zone may not be desirable in
suburban, urban, or urban core areas, or in other land use contexts that provide for non-
motorized uses, such as a forest, park, or within a scenic and recreational highway. In these
situations, analyze crash reports’ contributing factors to determine whether roadside vegetation
is contributing to the severity of crashes. If large vegetation is removed, consult guidance
contained in established vegetation management plans, corridor plans, or the WSDOT Roadside
Manual. Additional guidance for maintenance of roadside vegetation can be found for some
routes in the Memorandum of Understanding between the US Forest Service and WSDOT,
Highways Over National Forest Lands, dated July 2002. In incorporated cities, refer to guidance
in 1600.02(2).
1600.03(2)(b) Mailboxes

For mailboxes located within the Design Clear Zone, provide supports and connections as shown
in the Standard Plans. The height from the ground to the bottom of the mailbox is 3 feet 3
inches. This height may vary from 3 feet 3 inches to 4 feet if requested by the mail carrier. If the
desired height is to be different from 3 feet 3 inches, provide the specified height in the contract
plans. (See Exhibit 1600-7 for installation guidelines.) Coordinate with homeowners when
upgrading mailboxes.

Where sidewalks are present, contact the postal service to determine the most appropriate
mailbox location. Locate mailboxes on limited access highways in accordance with Chapter 530,
Limited Access. A turnout, as shown in Exhibit 1600-7, is not needed on limited access highways
with shoulders of 6 feet or more where only one mailbox is to be installed. On managed access
highways, mailboxes are to be on the right-hand side of the road in the postal carrier’s direction
of travel. Avoid placing mailboxes along high-speed, high-volume highways. Locate
Neighborhood Delivery and Collection Box Units outside the Design Clear Zone.
1600.03(2)(c) Culvert Ends
Provide a traversable end treatment when the culvert end section or opening is within the
Design Clear Zone. No part of the culvert or end treatment should protrude more than 4"
above the ground line. Traversable end treatments include:
 Culverts perpendicular to direction of travel:
o Culverts 36” and smaller as measured parallel to the direction of travel (Consider
treating these culvert ends even outside Design Clear Zone)
 For roadway side slopes 4:1 or steeper, see Standard Plan B-70.20
 For slopes flatter than 4:1 (see Standard Plan B-70.20 and note “treatment for
slopes flatter than 4:1”)
o Culverts larger than 36 inches, as measured parallel to the direction of travel,
require Type 1 safety bars. (See Standard Plan B-75.50)

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Chapter 1600 Roadside Safety

 Culverts parallel to direction of travel require safety bars:

o Type 2 safety bars are used for circular culverts up to 36 inches. (See Standard Plan
B-75.60)
o Type 3 safety bars are used for metal end sections of circular culverts between 36
inches and 60 inches and for metal end sections of arched culverts between 30
inches and 72 inches. (See Standard Plan B-80.20)
o Type 4 safety bars are used for metal end sections of circular culverts between 15
inches and 60 inches and for metal end sections of arched culverts between 18
inches and 72 inches. (See Standard Plan B-80.40)

Bars are permitted where they will not significantly affect the stream hydraulics and where
debris drift is minor. Consult the Region Maintenance Office and Region Hydraulics to verify
these conditions. If debris drift is a concern, consult Region Hydraulics for options to reduce the
amount of debris that can enter the pipe.
1600.03(2)(d) Signposts

Whenever possible, locate signs behind the standard run, but not the end terminals, of existing
or planned traffic barrier installations to eliminate the need for breakaway posts, and place
them such that the sign face is behind the barrier. (See Chapter 1020 for additional information
regarding the placement of signs.) Use the MUTCD to guide placement of the warning sign.

Signposts with cross-sectional areas greater than 16 square inches that are within the Design
Clear Zone and not located behind a barrier are to have breakaway features as shown in the
Standard Plans.

Sign bridges and cantilever sign supports are designed for placement outside the Design Clear
Zone or must be shielded by barrier.
1600.03(2)(e) Traffic Signal Standards/Posts/Supports

Breakaway signal posts generally are not feasible or desirable, and barrier is not generally an
option due to constraints typically found at intersection locations. To reduce potential for
drivers making contact with posts, and to avoid impeding the movement of pedestrian or
bicyclist traffic in the vicinity, locate posts in accordance with Chapter 1330.

For ramp meter systems, single lane ramp meters use breakaway Type RM signal standards.
Multilane ramp meters normally use Type II signal standards, which must either be located
outside of clear zone for all adjacent roadways or be protected by some type of barrier.

1600.03(2)(f) Fire Hydrants

Fire hydrants are typically allowed on WSDOT right of way by franchise or permit. Fire hydrants
that are made of cast iron can be expected to fracture on impact and can therefore be
considered a breakaway device. Any portion of the hydrant that will not be breakaway must not
extend more than 4 inches above the ground. In addition, the hydrant must have a stem that
will shut off water flow in the event of an impact. Provide mitigation to address potential vehicle
impact with hydrant types not expected to fracture on impact.

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Roadside Safety Chapter 1600

1600.03(2)(g) Utility Poles

Since utilities often share the right of way, utility objects such as poles are often located along
the roadside. It is normally undesirable or infeasible to install barrier for all of these objects, so
mitigation is usually in the form of relocation (underground or to the edge of the right of way) or
delineation. In some instances where there is a history of impacts with poles and relocation is
not possible, a breakaway design might be appropriate.

Evaluate roadway geometry and crash history as an aid in determining locations that exhibit the
greatest need. Contact the Headquarters (HQ) Design Office for information on breakaway
features. Coordinate with the HQ Utilities Unit when appropriate.

For policy and guidance on locating utility poles along state highways, also see Chapter 9 of the
Utilities Manual. Document the determination of appropriate mitigative measures and
coordination with the region Utilities Office.

1600.03(2)(h) Light Standards

Provide breakaway light standards unless fixed light standards can be justified, even if outside of
the Design Clear Zone. Fixed light standards may be justified if one of the following criteria are
met:
 Posted speed is below 35 MPH (See 1600.02(1) for Design Clear Zone in urbanized and
urbanizing areas, and 1600.02(2) in cities).
 Mounted on barrier (top or elbow mount).
 Behind traffic barrier, beyond the barrier’s deflection design value (see Chapter 1610).
 Within a parking lot.
 Along isolated walkways and shared-use paths that are outside of Design Clear Zone.

Breakaway light standards require additional embankment widening to ensure proper

operation, as shown in the Standard Plans. If this additional embankment widening
cannot be constructed, such as in cases where the toe of slope will extend beyond right of
way or into a water body or other sensitive area, fixed bases and traffic barrier may be
considered. Document the decision to use fixed bases in the Design Documentation
Package.

1600.03(3) Water
Water with a depth of 2 feet or more and located with a likelihood of encroachment by an
errant vehicle is to be evaluated for mitigation.

Perform a benefit-cost analysis that considers the consequences of doing nothing versus
installing a longitudinal barrier to determine the appropriate treatment (see Chapter 321 for
more information). For fencing considerations along water features see Chapter 560.

1600.04 Medians
Median barriers are normally used on limited access, multilane, high-speed, high-volume
highways. These highways generally have posted speeds of 45 mph or higher. Median barrier is
normally placed on limited access state highways. Where median barrier is used on managed
access highways where bicyclists, pedestrians, and transit users are present, consider providing

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Chapter 1600 Roadside Safety

accessible barrier openings at crossing locations. Providing access through median barrier
results in openings, therefore, end treatments are needed.

Provide median barrier on full access control multilane highways with median widths of 50 feet
or less and posted speeds of 45 mph or higher. Consider median barrier on highways with wider
medians or lower posted speeds when there is a history of cross-median crashes. Contact the
HQ Design Office for more information.

Provide a left-side shoulder when installing median barrier using width criteria given in Chapter
1230. Consider a wider shoulder area where the barrier might cast a shadow on the roadway
and hinder the melting of ice. (See Chapter 1239 for additional criteria for placement of median
barrier, Chapter 1610 for information on the types of barriers that can be used, and Chapter
1260 for lateral clearance on the inside of a curve to provide the needed stopping sight
distance.) Consider the need to accommodate drainage as a result of the addition of median
barrier treatments.

When median barrier is being placed in an existing median, identify the existing crossovers and
enforcement observation points. Provide the needed median crossovers in accordance with
Chapter 1370, considering enforcement needs. Chapter 1410 provides guidance on HOV
enforcement.

1600.05 Other Roadside Safety Features

1600.05(1) Rumble Strips

Rumble strips are milled grooves or rows of raised pavement markers placed perpendicular to
the direction of travel, or a continuous sinusoidal pattern milled longitudinal to the direction of
travel, intended to alert inattentive drivers to a potential lane departure. A sinusoidal pattern
can be used when a low noise design is desired.

The pavement receiving rumble strips needs to be in good condition and thick enough to
support the rumble strips. Certain pavement types, such as open graded pavements, are not
suitable for rumble strip installation. Grinding rumble strips into inadequate pavement will lead
to premature deterioration of the surrounding pavement. Areas where the pavement is
inadequate for rumble strip installation require removal and replacement of the existing
pavement at and adjacent to the location of the rumble strip. Consult with the Region Materials
Engineer to determine whether the existing pavement is adequate for rumble strip installation.
The Region Materials Engineer will provide a pavement design for removing and replacing the
existing pavement near the rumble strip if needed. When installing both rumble strips and
recessed lane markers, follow the Standard Plan to avoid overlapping the grindings.

Installing rumble strips in bituminous surface treatment (or BST) or other thin surface
treatments can expose pavement structure and lead to delamination. In new rumble strip
locations where BST will be applied on an Hot Mix Asphalt (HMA) pavement, install the rumble
strips in the HMA pavement before placing the BST. In existing rumble strip locations, note that
a single application of BST on top of an existing rumble strip installation typically results in
satisfactory rumble strip depth. Where rumble strips currently exist and an additional BST
application is contemplated, evaluate whether the depth of the grooves following paving will
provide their continuing function to alert drivers. If not, or in the case of an HMA overlay, it may
be necessary to remove existing rumble strips and install new ones.

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Roadside Safety Chapter 1600

Provide an offset to the longitudinal paving joint so that rumble strips are not ground into the
joint where practicable. For additional guidance on surface preparation and pavement stability,
refer to the WSDOT Pavement Policy.

The noise created when vehicle tires contact a rumble strip may adversely impact nearby
residences and other land uses. Left-turning or passing vehicles, frequent passing maneuvers on
two lane highways, and off-tracking of vehicles or trailers in tight radius curves, are examples of
situations where incidental contact can happen. Noise impacts may be anticipated, and a low
noise rumble strip design may be warranted, when installing rumble strips in urban growth
areas, and/or within 600 feet of a residence, school, church, or campground. In situations where
a low noise rumble strip is desired but is not feasible, measures can still be taken to reduce
incidental contact, including discontinuing the rumble strip through frequently used road
approaches, through passing zones, and in tight radius curves. Contact HQ Design for more
information about low noise rumble strip designs, noise mitigation strategies, and the criteria
for employing them.

There are three types of rumble strip functions: roadway, shoulder, and centerline, and each are
described in the following sections.

1600.05(1)(a) Roadway Rumble Strips

Roadway rumble strips are placed transversely in the traveled way to alert drivers who are
approaching a change of roadway condition or object that requires substantial speed reduction
or other maneuvering. Some locations where advance roadway rumble strips may be placed
include:
 Stop-controlled intersections
 Port of entry/customs stations
 Lane reductions where crash history shows a pattern of driver inattention, and
 Horizontal alignment changes where crash history shows a pattern of driver
inattention.

They may also be placed at locations where the character of the roadway changes, such as at
the end of a freeway.

Contact the HQ Design Office for additional guidance on the design and placement of roadway
rumble strips.

Document decisions to use roadway rumble strips in the Design Documentation Package.

1600.05(1)(b) Shoulder Rumble Strips and Rumble Stripes

Shoulder rumble strips (SRS) are placed parallel to the traveled way just beyond the edge line to
warn drivers they are entering a part of the roadway not intended for routine traffic use.
Shoulder rumble stripes are rumble strips placed immediately under the shoulder delineation
paint, with any excess width milled or placed outward towards the shoulder. Shoulder rumble
stripes are only installed where there is insufficient space to install shoulder rumble strips per
one of the standard configurations (see Section 1600.05(1)(b)(2)).

When shoulder rumble strips and shoulder rumble stripes are used, discontinue them where no
edge stripe is present, such as at intersections and where curb and gutter are present.
Discontinue shoulder rumble strips and rumble stripes where shoulder driving is allowed.

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Chapter 1600 Roadside Safety

Shoulder rumble strip and rumble stripe patterns vary depending on whether bicyclists are
expected to use the highway shoulder, and whether they are placed on divided or undivided
highways. Rumble strip patterns for undivided highways are shallower and may be narrower
than patterns used on divided highways. Rumble strips and rumble stripes installed on
undivided highways also provide gaps in the pattern, providing opportunities for bicycles to
move across the pattern without having to ride across the grooves. There are four shoulder
rumble strip and four shoulder rumble stripe patterns. Consult the Standard Plans (rumble
strips) or Plan Sheet Library (rumble stripes) for patterns and construction details.
1. Divided Highways

Install shoulder rumble strips on both the right and left shoulders of rural Interstate highways.
Consider them on both shoulders of rural divided highways. Use the Shoulder Rumble Strip or
rumble stripe Type 1 pattern on divided highways.

Shoulder rumble strips and rumble stripes may be omitted under any of the following
conditions:
 When another project scheduled within two years of the proposed project will overlay
or reconstruct the shoulders or will use the shoulders for detours.
 When overall shoulder width is less than 4 feet wide on the left and 6 feet wide on the
right. The minimum right shoulder width is reduced to 5 feet where rumble stripes are
used.
2. Undivided Highways

Shoulder rumble strips or rumble stripes are considered on undivided highways during
centerline rumble strip installation or pavement rehabilitation. A list of prospective locations are
provided to regions by HQ Design as a starting point in their development of a final list. The final
list is compiled based on a detailed review of the prospective locations using the following
criteria. Document decisions to omit prospective locations in the final list.

Shoulder rumble strips or stripes may be omitted from a highway segment under any of the
following conditions:
 Where at least 4 feet of usable shoulder between the rumble strip and the outside
edge of shoulder cannot be provided. In cases where guardrail or barrier is present,
increase this dimension to a minimum of 5 feet of usable shoulder. Field-verify these
dimensions.
 Where downhill grades exceed 4% for more than 500 feet in length along routes where
bicyclists are frequently present.
 Where sections of rumble strips are omitted as a measure to reduce noise (see Section
1600.05(1)).

When selecting a rumble strip or rumble stripe design, consult the Standard Plans and Plan
Sheet Library for the patterns and construction details, and apply the following criteria:
 Consider using a low noise pattern, or employ measures to reduce incidental contact,
in areas where noise impacts are anticipated (apply criteria in Section 1600.05(1)).
 Consider using a rumble stripe pattern where usable shoulder width is less than 4 feet
(5 feet where barrier is present).

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February 2019
Roadside Safety Chapter 1600

 The Shoulder Rumble Strip Type 2 or Type 3 pattern is used on highways with minimal
bicycle traffic. Use the Shoulder Rumble Strip Type 4 pattern where the bicycle traffic
level on the shoulder is determined to be high. Consult the region and Headquarters
Bicycle and Pedestrian Coordinators to determine the bicycle traffic level, and engage
them in decision-making processes related to the use of rumble strips or rumble
stripes on bike touring routes, and/or on other routes where bicycle events are
regularly held.

Document the decision to omit shoulder rumble strips or rumble stripes in a Design Analysis,
when that decision is outside of the policy provided in this section (see Chapter 300.)

1600.05(1)(c) Centerline Rumble Strips

Centerline rumble strips are installed on the centerline of undivided highways to alert drivers
that they are entering the opposing lane. They are installed with no differentiation between
passing permitted and no passing areas. Refresh pavement markings when removed by
centerline rumble strips.

Centerline rumble strips are typically installed on rural highways where the posted speed is 45
mph or higher. They may also be installed on urban routes with posted speeds as low as 35
mph. A list of prospective centerline rumble strip installation locations are provided to regions
by HQ Design as a starting point in their development of a final list. The final list is compiled
based on a detailed review of the prospective locations using the following criteria.
 Field verify lane and shoulder widths. See Chapter 1230 for guidance on lane and
shoulder widths. Centerline rumble strips are only installed where the combined lane
and shoulder width in either direction is greater than 12 feet.
 In locations where the combined lane and shoulder width in either direction is 14 feet
or less, consider the level of bicyclist and pedestrian use along the route before
installing centerline rumble strips. When drivers shift their lane position away from
centerline to avoid the rumble strips, they are moving closer to pedestrians and
bicyclists on the shoulder.
 Consider using a low noise rumble strip design in locations where noise is an issue, or
employ measures for reducing incidental contact where a low noise design is not
feasible (apply criteria in Section 1600.05(1)).
 In urban areas, do not consider installing rumble strips where the need to interrupt the
rumble strip pattern to accommodate left-turning vehicles is very frequent, or where
the posted speed is 35 mph and below.
 Do not use centerline rumble strips where two way left-turn lanes exist.
Document the decision to omit centerline rumble strips in a Design Analysis, when that
decision is outside of the policy provided in this section (see Chapter 300.)

1600.05(2) Headlight Glare Considerations

Headlight glare from opposing traffic is most common between opposing main line traffic. Glare
screens can be used to mitigate this condition. Other conditions for which glare screen might be
appropriate are:

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February 2019
Chapter 1600 Roadside Safety

 Between a highway and an adjacent frontage road, multi-use path, or parallel highway,
especially where opposing headlights might seem to be on the wrong side of the driver.
 At an interchange where an on-ramp merges with a collector-distributor and the ramp
traffic might be unable to distinguish between collector and main line traffic.
 Where headlight glare is a distraction to adjacent property owners. Playgrounds, ball
fields, and parks with frequent nighttime activities might benefit from screening if
headlight glare interferes with these activities.

Glare screening is normally not justifiable where the median width exceeds 20 feet, and the ADT
is less than 20,000 vehicles per day. Document the decision to use glare screening using the
following criteria:
 Higher frequency of night crashes compared to similar locations or based on statewide
experience.
 Higher than normal ratio of night-to-day crashes.
 Unusual distribution or concentration of nighttime crashes.
 Over-representation of older drivers in night crashes.
 Combination of horizontal and vertical alignment, particularly where the roadway on
the inside of a curve is higher than the roadway on the outside of the curve.
 Direct observation of glare.
 Public complaints concerning glare.

There are currently three basic types of glare screening available: chain link (see the Standard
Plans), vertical blades, and concrete barrier (see Exhibit 1600-8).

When the glare is temporary (due to construction activity), consider traffic volumes, alignment,
duration, presence of illumination, and type of construction activity. Glare screening may be
used to reduce rubbernecking associated with construction activity, but less expensive methods,
such as plywood that seals off the view of the construction area, might be more appropriate.

1600.06 Documentation
Refer to Chapter 300 for design documentation requirements.

1600.07 References

1600.07(1) Federal/State Laws and Codes

Revised Code of Washington (RCW) 47.24.020(2), Jurisdiction, control

RCW 47.32.130, Dangerous objects and structures as nuisances

1600.07(2) Design Guidance

Highway Safety Manual, AASHTO

Local Agency Guidelines (City and County Design Standards), M 36-63, WSDOT

WSDOT Design Manual M 22-01.16 Page 1600-13

February 2019
Roadside Safety Chapter 1600

Roadside Design Guide, AASHTO, 2011

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01, WSDOT

1600.07(3) Supporting Information

A Policy on Geometric Design of Highways and Streets (Green Book), AASHTO, 2011

Understanding Design Clear Zone – This e-learning course for WSDOT employees covers how to
determine the appropriate Design Clear Zone for recoverable and nonrecoverable slopes as well
as ditches. Request this training via the web-based Learning Management System.

Highways Over National Forest Lands, MOU, 2013, US Forest Service and WSDOT,
 www.wsdot.wa.gov/publications/manuals/m22-50.htm

Utilities Manual, M 22-87, WSDOT. Chapter 9 provides Control Zone guidance for utilities in the
WSDOT right of way.

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Chapter 1600 Roadside Safety

Exhibit 1600-2 Design Clear Zone Distance Table

Posted Average Cut Section (Backslope) Fill Section

Speed Daily (H:V) (H:V)
(mph) Traffic 3:1 4:1 5:1 6:1 8:1 10:1 3:1 4:1 5:1 6:1 8:1 10:1
35 or Less The Design Clear Zone Distance is 10 ft
Under 250 10 10 10 10 10 10 * 13 12 11 11 10
251 – 800 11 11 11 11 11 11 * 14 14 13 12 11
40 801 – 2,000 12 12 12 12 12 12 * 16 15 14 13 12
2,001 – 6,000 14 14 14 14 14 14 * 17 17 16 15 14
Over 6,000 15 15 15 15 15 15 * 19 18 17 16 15
Under 250 11 11 11 11 11 11 * 16 14 13 12 11
251 – 800 12 12 13 13 13 13 * 18 16 14 14 13
45 801 – 2,000 13 13 14 14 14 14 * 20 17 16 15 14
2,001 – 6,000 15 15 16 16 16 16 * 22 19 17 17 16
Over 6,000 16 16 17 17 17 17 * 24 21 19 18 17
Under 250 11 12 13 13 13 13 * 19 16 15 13 13
251 – 800 13 14 14 15 15 15 * 22 18 17 15 15
50 801 – 2,000 14 15 16 17 17 17 * 24 20 18 17 17
2,001 – 6,000 16 17 17 18 18 18 * 27 22 20 18 18
Over 6,000 17 18 19 20 20 20 * 29 24 22 20 20
Under 250 12 14 15 16 16 17 * 25 21 19 17 17
251 – 800 14 16 17 18 18 19 * 28 23 21 20 19
55 801 – 2,000 15 17 19 20 20 21 * 31 26 23 22 21
2,001 – 6,000 17 19 21 22 22 23 * 34 29 26 24 23
Over 6,000 18 21 23 24 24 25 * 37 31 28 26 25
Under 250 13 16 17 18 19 19 * 30 25 23 21 20
251 – 800 15 18 20 20 21 22 * 34 28 26 23 23
60 801 – 2,000 17 20 22 22 23 24 * 37 31 28 26 25
2,001 – 6,000 18 22 24 25 26 27 * 41 34 31 29 28
Over 6,000 20 24 26 27 28 29 * 45 37 34 31 30
Under 250 15 18 19 20 21 21 * 33 27 25 23 22
251 – 800 17 20 22 22 24 24 * 38 31 29 26 25
65 801 – 2,000 19 22 24 25 26 27 * 41 34 31 29 28
2,001 – 6,000 20 25 27 27 29 30 * 46 37 35 32 31
Over 6,000 22 27 29 30 31 32 * 50 41 38 34 33
Under 250 16 19 21 21 23 23 * 36 29 27 25 24
251 – 800 18 22 23 24 26 26 * 41 33 31 28 27
70 801 – 2,000 20 24 26 27 28 29 * 45 37 34 31 30
2,001 – 6,000 22 27 29 29 31 32 * 50 40 38 34 33
Over 6,000 24 29 31 32 34 35 * 54 44 41 37 36

Notes:
This exhibit applies to:
 All state highways outside incorporated cities.
 Limited access state highways within cities.
For Roadside and Median areas on managed access state highways within incorporated cities, see 1600.02 for
guidance. Curb is not considered adequate to redirect an errant vehicle.
Design Clear Zone distances are given in feet, measured from the edge of traveled way.
*When the fill section slope is steeper than 4H:1V, but not steeper than 3H:1V, the Design Clear Zone distance is
modified by the recovery area formula (see Exhibit 1600-4) and is referred to as the recovery area. The basic
philosophy behind the recovery area formula is that the vehicle can traverse these slopes but cannot recover
(control steering); therefore, the horizontal distance of these slopes is added to the Design Clear Zone distance to
form the recovery area. Provide a minimum of 10 feet at the toe of all traversable, non‐recoverable fill slopes.

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Roadside Safety Chapter 1600

Exhibit 1600-3 Design Clear Zone Inventory Form

See: www.wsdot.wa.gov/design/support.htm for this form template in PDF, Word, or Excel spreadsheet.
(PDF Shown Below) Remember, this form has 2 sides when copying.

Front sheet

Back sheet

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Chapter 1600 Roadside Safety

Exhibit 1600-4 Recovery Area

* When the fill section slope is steeper than 4H:1V, but not steeper than 3H:1V, the Design Clear Zone
distance is modified by the recovery area formula (see Exhibit 1600-4) and is referred to as the recovery
area. The basic philosophy behind the recovery area formula is that the vehicle can traverse these slopes
but cannot recover and return to the roadway (control steering); therefore, the horizontal distance of
these slopes is added to the Design Clear Zone distance to form the recovery area.

Formula:

Recovery area = (shoulder width) + (nonrecoverable slope distance) +

the greater of [10 ft or (Design Clear Zone distance – shoulder width)]

Example: Fill section (fore slope 3H:1V and 6H:1V)

Conditions:
Speed = 45 mph
Traffic = 3,000 ADT
Fore Slope = 3H:1V (Nonrecoverable)
Fill Slope = 6H:1V = 17 ft from Exhibit 1600‐2

Criteria:
Fore Slope 3H:1V  Use recovery area formula
Recovery area = (shoulder width (8 ft)) + (nonrecoverable slope distance (12 ft)) + Greater of (1) or (2):
(1) 10 ft
(2) Design Clear Zone distance for 6H:1V (17 ft) – shoulder width (8 ft)) = 9 ft

Recovery area = 20 + 10 ft = 30 feet

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Roadside Safety Chapter 1600

Exhibit 1600-5 Design Clear Zone Examples for Ditch Sections

Case 1: Cut section with ditch (foreslope 4H:1V of flatter)

Conditions:
Design Clear Zone = 23 ft
Speed = 55 mph
6 ft 8 ft 3 ft
Traffic = 4,200 ADT Shoulder
Slope = 4H:1V
Edge of 4H:1
Criteria: V 1V
traveled way 3H:
Greater of:
(1) Design Clear Zone for 10H:1V cut section, 23 ft
(2) 5 feet horizontal beyond beginning of back slope, 22 feet

Design Clear Zone = 23 feet

Case 2: Cut section with ditch (foreslope steeper than 4H:1V and backslope steeper than 3H:1V)
Conditions: NA
Design Clear Zone = 19 ft
Criteria: 10 feet horizontal beyond
beginning of backslope 3 ft 6 ft 10 ft
Shld
Design Clear Zone = 19 feet
1V
2H :
3H:1
Edge of V
traveled way

Case 3: Cut section with ditch (foreslope 3H:1V or steeper and backslope not steeper than 3H:1V)
Conditions:
Design Clear Zone = 21 ft
Speed = 45 mph
Traffic = 3,000 ADT 6 ft 6 ft
Shoulder
Foreslope = 2H:1V
Backslope = 4H:1V 2H
:1V
Edge of 4H:1V
Criteria: Use recovery area formula traveled way

Recovery area = (shoulder width) + (horizontal distance) + (Design Clear Zone distance – shoulder width)

= 6 + 6 + (15 – 6 ) = 21

Recovery Area = 21 feet

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Chapter 1600 Roadside Safety

Exhibit 1600-6 Guidelines for Embankment Barrier

Below curve: barrier

recommended on
new installations

Note:

Routes with ADTs under 400 may be evaluated on a case-by-case basis.

WSDOT Design Manual M 22-01.16 Page 1600-19

February 2019
Roadside Safety Chapter 1600

Exhibit 1600-7 Mailbox Location and Turnout Design

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Chapter 1600 Roadside Safety

Exhibit 1600-8 Glare Screens

WSDOT Design Manual M 22-01.16 Page 1600-21

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Roadside Safety Chapter 1600

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February 2019
Chapter 1610 Traffic Barriers
1610.01 Introduction
1610.02 Barrier Impacts
1610.03 General Barrier Design Considerations
1610.04 Beam Guardrail
1610.05 High-Tension Cable Barrier
1610.06 Concrete Barrier
1610.07 Bridge Traffic Barriers
1610.08 Other Barriers
1610.09 References

Chapter Organization: The first sections (Introduction and Barrier Impacts) present information to
consider when deciding whether to install a barrier. The next section (General Barrier Design
Considerations) contains guidance common to ALL barrier types, such as deflection distance, length
of need and sight distance. The remaining sections present design information organized by
specific barrier type (beam guardrail, cable barrier, etc.).

Refer to the Design Manual Glossary for many of the terms used in this chapter.

Refer to Chapter 300 for design documentation requirements.

1610.01 Introduction
WSDOT uses traffic barriers to reduce the overall severity of crashes. Consideration is given
as to whether a barrier is preferable to the recovery area it may replace. In some cases,
installation of a traffic barrier may result in more crashes as it presents an object that can be
struck. Barriers are designed so that such encounters might be less severe and not lead to
secondary or tertiary crashes. However, traffic barriers are not guaranteed to redirect an
impacting vehicle without resulting injury to its occupants or triggering additional crashes.
Barrier performance is affected by the characteristics of the vehicles that collide with them.
Different vehicles will react differently given the characteristics and dynamics of the crash.
Therefore, vehicles will be decelerated and redirected differently given the size, weight and
direction of force imparted from the vehicle to the barrier.

Barriers are not placed with the assumption that the system will restrain or redirect all
vehicles in all conditions. It is recognized that the designer cannot design a system that will
address every potential crash situation. Instead, barriers are placed with the assumption
that, under typical crash conditions, they might decrease the potential for excessive vehicular
deceleration or excessive vehicle redirection when compared to the location without the
barrier.

Traffic barriers do not prevent crashes or injuries from occurring. They often lower the
potential severity for crash outcomes. Consequently, barriers should not be used unless a
reduced crash severity potential is likely. No matter how well a barrier system is designed,
optimal performance is dependent on drivers’ proper maintenance and operation of their
vehicles and the proper use of passenger restraint systems. The ultimate choice of barrier

WSDOT Design Manual M 22-01.18 Page 1610-1

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Traffic Barriers Chapter 1610

type and placement should be made by gaining an understanding of site and traffic
conditions, having a thorough understanding of and applying the criteria presented in
Chapters 1600 and 1610, and using engineering judgment.

Barrier systems and vehicle fleets continue to evolve. The choice of a barrier is based on the
characteristics of today’s vehicle fleet and testing criteria, not on speculative assumptions of
future vehicle designs. This continuum of change does not allow engineers to predict the
future with any degree of certainty. Consequently, engineering decisions need to be made
based on the most reliable and current information.

Engineers are constantly striving to develop more effective design features to improve
highway safety. However, economics, asset management and maintenance needs, and
feasibility do not permit the deployment of new designs as soon as they become available on
the market or are invented by a manufacturer. Further, most new designs only make
marginal changes to systems and do not imply that old designs are unsafe or need
modification.

Solutions may consider crash frequency and severity. As discussed previously, performance
of the system relies on the interaction of the vehicle, driver, and system design at any given
location. Additionally, the ability to safely access, maintain and operate over time is
incorporated into the final barrier decision.

When barriers are crash-tested, it is impossible to replicate the innumerable variations in

highway conditions under which the barrier applications occur. Therefore, barriers are crash-
tested under standardized conditions. These standard conditions were previously
documented in National Cooperative Highway Research Program (NCHRP) Reports 230 and
350. These guidelines have been updated and are now presented in the AASHTO publication,
Manual for Assessing Safety Hardware (MASH).

As roadside safety hardware changes occur on the highway system they will use MASH crash
testing criteria instead of NCHRP Report 350. To learn more about WSDOT’s plan for
implementing MASH-compliant hardware see the following website:
 http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm

1610.01(1) Site Constraints

Site constraints play a major role in decisions regarding guardrail selection and placement.
Depending on the location, these constraints may include (but are not limited to)
environmental considerations, topographic challenges, restricted right-of-way, geologic
concerns or conflicts with other infrastructure to name just a few. Document barrier location
decisions, including any site constraints encountered that influenced those decisions. A
decision to install barrier using criteria outside the guidance provided in this chapter requires
a Design Analysis (See Chapter 300).

1610.02 Barrier Impacts

Engineering judgment is required in determining the appropriate placement of barrier
systems, therefore consider the location of the system and the possible impacts the barrier
may have to other highway objectives.

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Chapter 1610 Traffic Barriers

1610.02(1) Assessing Impacts to Stormwater and Wetlands

The presence of stormwater facilities or wetlands influence the choice and use of barrier
systems. For example, the placement of concrete barrier may increase the amount of
impervious surface, which could then result in retrofit or reconstruction of the existing
retention/detention systems and environmental impact requirements and studies. Assess
whether concrete barrier or beam guardrail placement will cause the need for an evaluation
by the HQ Environmental Services Office. Conduct this evaluation early in the project’s
development process to allow adequate time for discussion of options.

1610.02(2) Assessing Impacts to Wildlife

The placement of concrete barriers in locations where wildlife frequently cross the highway
can influence wildlife-vehicle crash potential. When wildlife encounters physical barriers that
are difficult to see beyond or cross, such as concrete barriers, they often stop or move
parallel to those barriers, increasing their time on the highway and their exposure.

Traffic-related wildlife mortality may play a role in the decline of some species listed under
the Endangered Species Act. To address wildlife concerns, see Exhibit 1610-1 to assess
whether barrier placement needs to have an evaluation by the HQ Environmental Services
Office to determine its effect on wildlife. Conduct this evaluation early in the project
development process to allow adequate time for discussion of options.

Exhibit 1610-1 Concrete Barrier Placement Guidance: Assessing Impacts to Wildlife

Will the barrier be

Does the project propose to use a concrete barrier? installed on or adjacent to
lands administered by a
federal or state agency or
YES an American Indian Tribe
NO NO or private conservation
organization?
Will the barrier be left within the same NO
milepost limits for greater than 60 days?
No Contact NO
Necessary YES
YES Will the barrier be installed in a
WSDOT-identified highway
segment with a high or medium
Is the project located entirely within a YES
rank for wildlife-related safety
developed urban area? (Consult
or ecological stewardship
Highway Log)
(information available on
WSDOT Environmental
NO Workbench under Habitat
YES Connectivity), or in a section of
Contact the Region or
Is right of way fenced with 6-foot YES highway posted with wildlife
or higher chain link or wire mesh
HQ Environmental warning signs?
fence? Services Office
for Assistance in
NO
NO Determining the Effect YES
YES of Barrier Placement
Will the barrier be installed
Will the barrier be entirely on an elevated adjacent to a stream, river,
structure (bridge, overpass, viaduct)? wetland, lake, or pond?
NO

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Traffic Barriers Chapter 1610

1610.03 General Barrier Design Considerations

See Chapter 1105 Design Element Selection for guidance regarding required design elements
for the various different project types (programs and subprograms).

Chapter 1120 identifies those elements and features to be evaluated and potentially
addressed during the course of a Preservation project.

Follow the guidance in this chapter for any project that introduces new barrier onto the
roadside (including median section) and follow the guidance in Chapter 1600 for removal of
barrier that is not needed. Slope flattening is recommended when the crash reduction
benefit justifies the additional cost to eliminate the need for barrier.

When selecting a barrier, consider the barrier system’s deflection characteristics, cost,
maintainability and impacts to traffic flow during repair. Barriers are categorized as flexible,
semi-rigid, or rigid depending on their deflection characteristics (see Exhibit 1610-3). Barrier
types include:
 Beam Guardrail
 Cable Barrier
 Concrete Barrier
 Bridge Traffic Barrier
 Other Barriers

Since non-rigid systems typically sustain more damage during an impact, consider the
amount of traffic exposure maintenance crews might incur with the more frequent need for
repairs.

The costs for procuring and maintaining the barrier system are important factors when
considering what system to install. Considerations may include:
 Consultation with the Area Maintenance Superintendent to identify needs or
recommendations.
 Drainage, alignment, and drifting snow or sand are considerations that can
influence the selection of barrier type. Beam guardrail and concrete barrier can
contribute to snow drifts. Consider long-term maintenance costs associated with
snow removal at locations prone to snow drifting. Cable barrier is not an
obstruction to drifting snow.
 Analysis of potential reduction of sight distance due to barrier selection and
placement.
 Additional widening and earthwork requirements. With some systems, such as
concrete barrier and beam guardrail, the need for additional shoulder widening or
slope flattening is common. Selection of these types of barriers may require
substantial environmental permitting or roadway reconstruction. Permits issued
under the SEPA and NEPA processes may lead to the use of a barrier design, such as
cable barrier, which has fewer potential environmental impacts and costs.
 For concrete barrier systems:
o Lower maintenance costs than for other barrier types.

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Chapter 1610 Traffic Barriers

o Deterioration due to weather and vehicle impacts is less than most other
barrier systems.
o Unanchored precast concrete barrier can usually be realigned or
repaired after a vehicle impact. However, heavy equipment may be
necessary to reposition or replace barrier segments. Therefore, in
medians, consider the shoulder width and the traffic volume when
determining the acceptability of unanchored precast concrete barrier
versus rigid concrete barrier. See Exhibit 1610-3 for deflection area
requirements.

Consider the following for existing barrier systems:

 Install, replace, or modify transitions as discussed in 1610.04(6) Transitions and
Connections.
 When installing new terminals, extend the guardrail to meet the length-of-need
criteria found in Section 1610.03(5).
 When replacing damaged terminals, consider extending the guardrail to meet the
length of need criteria in 1610.03(5)
 When the end of a barrier has been terminated with a small mound of earth,
remove and replace with a terminal as described in 1610.06(3).
 Special use or aesthetic barriers may be used on designated Scenic Byway and
Heritage Tour routes if funding, permits, and approvals can be arranged (see
1610.08).
 Design Manual Chapter 1120 identifies specific requirements to be addressed for a
Preservation project. For other projects, address barrier runs that include:
o W-beam guardrail with 12-foot 6-inch post spacing, or no blockouts, or
both.
o W-beam guardrail on concrete posts.
o Cable barrier on wood or concrete posts.
o Half-moon or C-shaped rail elements.

1610.03(1) Barrier Placement Considerations

Proper installation of a barrier system is required for the system to perform similar to the
crash tests that resulted in its acceptance for use on our highways. Maximize the distance
between the barrier and the travelled way.

See Chapter 1239 for minimum lateral clearance requirements.

1610.03(1)(a) Placement on a Slope

Slopes may affect barrier placement. Considerations for barrier placement on a slope
include:
 For slopes that are 10:1 or flatter, concrete barrier, beam guardrail or cable barrier
can be installed anywhere beyond the edge of shoulder. See Exhibit 1610-2.
 For additional placement guidance see 1610.05(1) for cable barrier, see 1610.04(2)
for beam guardrail, and see 1610.06 for concrete barrier.

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Traffic Barriers Chapter 1610

Exhibit 1610-2 Traffic Barrier Locations on Slopes

1610.03(1)(b) Placement in Median Locations

Considerations for barrier placement in a median include:

 Address the design deflection characteristics of the barrier to avoid placement of
barrier where the design deflection extends into oncoming traffic.
 Narrow medians provide little space for any maintenance activities, including repair
or repositioning of the barrier. Installing barriers in medians that provide less than 8
feet from the edge of the traveled way to the face of the barrier will likely require
temporarily closing the adjacent lane during maintenance activities. This will impact
the travelling public and impact maintenance staff, and maintenance staff should be
consulted. See Chapter 301 Design and Maintenance Coordination.
 At locations where the roadways are on independent alignments and there is a
difference in elevation between the roadways, the slope from the upper roadway
might be steeper than 6H:1V. In these locations, position the median barrier along
the upper roadway and provide deflection and offset distance as discussed
previously. Barrier is generally not needed along the lower roadway except where
there are fixed features in the median.
 In wider medians, the selection and placement of barrier might depend on the
slopes in the median. At locations where the median slopes are relatively flat
(10H:1V or flatter), unrestrained precast concrete barrier, beam guardrail, and cable
barrier can be used depending on the available deflection distance. At these
locations, position the barrier as close to the center of the median as possible so
that the recovery distance can be maximized for both directions. There may be a
need to offset the barrier from the flow line to avoid impacts to the drainage flow.
 In general, cable barrier is recommended with medians that are 30 feet or wider.
However, cable barrier may be appropriate for narrower medians if adequate
deflection distance exists.
 When W-beam barrier is placed in a median as a countermeasure for cross-median
crashes, design the barrier to be struck from either direction of travel. For example,
the installation of beam guardrail might be double-sided (Type 31-DS).
 For additional placement guidance see 1610.05(1) for cable barrier, see 1610.04(2)
for beam guardrail, and see 1610.06 for concrete barrier.

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1610.03(2) Sight Distance

When selecting and placing a barrier system, consider the possible impact the barrier type
and height may have on sight distance. In some cases, barriers may restrict the sight
distances of road users entering the roadway, such as from road approaches, intersections,
and other locations. In these cases, the barrier may need to be adjusted to meet the sight
distance requirements at these locations.

1610.03(3) Barrier Deflections

Expect all barriers, except for certain types of rigid barriers (such as concrete bridge rails,
barrier integral to retaining walls, or embedded cast-in-place barriers), to deflect when hit by
an errant vehicle. The amount of deflection is primarily dependent on the stiffness of the
system. However, vehicle speed, angle of impact, and weight of the vehicle also affect the
amount of barrier deflection.

For roadside or wide median installations of flexible and semi-rigid roadside barriers (high
tension cable barrier and beam guardrail), the deflection distance is designed to prevent the
impacting vehicle from striking the object being shielded. For unrestrained rigid systems
(unanchored precast concrete barrier), the deflection distance is designed to help prevent
the barrier from being knocked over the side of a drop-off or steep fill slope (2H:1V or
steeper).

For narrower median installations, design systems so that the anticipated deflection will not
enter the lane of opposing traffic. When evaluating new barrier installations, consider
whether impacts would require significant traffic closures to accomplish maintenance. Rigid
embedded barrier systems are used when no barrier deflection is necessary or desired (areas
such as narrow medians, at the edge of bridge decks, or other vertical drop-off areas). Runs
of rigid embedded concrete barrier can be precast, cast in place, or extruded with
appropriate footings.

In locations where deflection distance is limited, precast concrete barrier can be anchored.
Some movement can be expected for rigid anchored barrier systems and repairs may be
more expensive (anchoring pins may damage the asphalt or concrete surface that the barrier
is placed upon during a vehicle collision).

Use of an anchored precast concrete barrier and other deflecting barrier systems placed on
top of a retaining wall at less than the deflection distances provided in Exhibit 1610-3
requires approval from the HQ Design Office. See 1610.06 for more information on concrete
barrier.

Exhibit 1610-3 provides barrier deflection design values when selecting standard runs of
longitudinal barrier. This exhibit does not provide deflection values for specialty barrier
systems or installations (for example long span guardrail systems, box culvert guardrail
systems, Type 31 barrier installed on a flare, etc.). Contact HQ Design for specialty barrier
systems or installations deflections. The deflection values for cable and beam guardrail are
minimum distances measured between the face of the barrier to the fixed feature. The
deflection values for concrete barrier are minimum distances measured from the back edge
of the barrier to the fixed feature, drop-off, or slope break.

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Exhibit 1610-3 Longitudinal Barrier Deflection

Barrier Type System Type Deflection Distance

6 ft to 10 ft typical [1]
High-tension cable barrier Flexible
(face of barrier to object)
3 ft [4]
Beam guardrail, Types 1, 1a, 2, and 10 Semi-rigid
(face of barrier to object)
4 ft
Beam guardrail, two‐sided Types 3, and 4 Semi-rigid
(nearest face of barrier to object)
Beam guardrail Type 31 5 ft
Semi‐rigid
(including two-sided and omitted post) (face of barrier to object)
Rigid 6 ft [2]
Permanent precast concrete barrier, unanchored
Unrestrained (back of barrier to object)
Rigid 3 ft [3]
Temporary precast concrete barrier, unanchored [5]
Unrestrained (back of barrier to object)
2 ft
Permanent precast concrete barrier, anchored Rigid Anchored
(back of barrier to object)
1 ft [3] [6]
Temporary precast concrete barrier, anchored [5] Rigid Anchored
(back of barrier to object)
Rigid
Cast in place or precast concrete barrier, embedded No deflection [7]
Embedded

Notes:

This exhibit provides deflection values for standard runs of barrier. It does not provide
deflection values for specialty systems or installations (e.g. long span guardrail systems, box
culvert guardrail systems, Type 31 barrier installed on a flare, etc.).
[1] See 1610.05(2)
[2] When placed in front of a 2H:1V or flatter fill slope and not shielding fixed
objects, the barrier deflection distance can be reduced to 2 feet.
[3] When used as temporary bridge rail, anchor all barrier when the back of barrier
is located within 3 feet of a drop-off.
[4] Place any new objects a minimum of 5 feet from the face of existing beam
guardrail type 1.
[5] Steel barrier is also available for temporary applications. See Ch. 1010 for more
information.
[6] When anchoring temporary precast concrete barrier on bridges or other drop-
offs, see applicable Standard Plans for anchorage details, lateral offsets, and
deflection distances.

[7] When placed in front of a fill slope or on top of an MSE wall, provide a minimum
distance of 2-feet of widening with a 10:1 or flatter slope from the back of barrier to
the slope break point.

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1610.03(4) Flare Rate

A roadside barrier is considered flared when it is not parallel to the edge of the traveled way.

Flare the ends of longitudinal barriers where site constraints allow (see 1610.01(1)). The four
functions of a flare are to:
 Maximize the distance between the barrier (and its terminal) and the travelled way.
 Reduce the length of need.
 Redirect an errant vehicle.
 Minimize a driver’s reaction to the introduction of an object near the traveled way.

Keeping flare rates as flat as site constraints allow preserves the barrier’s redirectional
performance and minimizes the angle of impact. It has also been shown that an object (or
barrier) close to the traveled way might cause a driver to shift laterally, slow down, or both.
The flare reduces this reaction by gradually introducing the barrier so the driver does not
perceive the barrier as an object to be avoided. The flare rates in Exhibit 1610-4 are intended
to satisfy the four functions listed above. Flares that are more gradual may be used. Flare
rates are offset parallel to the edge of the traveled way. Transition sections are not flared.

Situations exist where hardware installations may have barrier flare rates different than
shown in Exhibit 1610-4. If a Standard Plan for a barrier installation shows a different flare
rate than is shown in Exhibit 1610-4, the flare rate shown on the Standard Plan can be used.

Exhibit 1610-4 Longitudinal Barrier Flare Rates

Posted Speed Rigid & Rigid Unrestrained Rigid

Semi-rigid
(mph) Anchored System System
65–70 20:1 18:1 15:1
60 18:1 16:1 14:1
55 16:1 14:1 12:1
50 14:1 12:1 11:1
45 12:1 11:1 10:1
40 or below 11:1 10:1 9:1

1610.03(5) Length of Need

Length of need refers to the total length of longitudinal barrier needed to shield a fixed
feature.

In many cases, there may be a portion of the traffic barrier installation that is not redirective
in capability. For instance, if a run of concrete barrier is terminated with an impact
attenuator, there will likely be a section of the impact attenuator that is not redirective (see
Chapter 1620 for more information). Therefore, in most cases, the Length of Need does not
equal (i.e., it is shorter than) the actual physical length of the traffic barrier installation
required to achieve that length of need.

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Length of need is dependent on the location and geometrics of the object, direction(s) of
traffic, posted speed, motor vehicle traffic volume, and type and location of traffic barrier.

When designing a barrier for a fill slope (see Chapter 1600), the length of need begins at the
point where the need for barrier is recommended. For fixed objects and water, Exhibit 1610-
5 shows design parameters for determining the needed length of a barrier for both adjacent
and opposing traffic on relatively straight sections of highway.

When barrier is to be installed on the outside of a horizontal curve, the length of need can be
determined graphically as shown in Exhibit 1610-7. For installations on the inside of a curve,
determine the length of need as though it were straight. Also, consider the flare rate, barrier
deflection, and barrier end treatment to be used.

When beam guardrail is placed in a median, consider the potential for impact from opposing
traffic when conducting a length of need analysis. When guardrail is placed on either side of
objects in the median, consider whether the trailing end of each run of guardrail will shield
the leading end of the opposing guardrail. Shield the leading end when it is within the Design
Clear Zone of opposing traffic (see Exhibit 1610-8). This is also a consideration when objects
are placed in the outer separations between the main line and collector-distributors.

Before the actual length of need is determined, establish the lateral distance between the
proposed barrier installation and the object shielded. Provide a distance that is greater than
or equal to the anticipated deflection of the longitudinal barrier. (See Exhibit 1610-3 for
barrier deflections.) Place the barrier as far from the edge of the traveled way as possible
while maintaining the deflection distance.

If the end of the length of need is near an adequate cut slope, extend the barrier and embed
it in the slope (see 1610.04(5)). Avoid gaps of 300 feet or less. Short gaps are acceptable
when the barrier is terminated in a cut slope. If the end of the length of need is near the end
of an existing barrier, it is recommended that the barriers be connected to form a continuous
barrier. Consider maintenance access issues when determining whether or not to connect
barriers.

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Exhibit 1610-5 Barrier Length of Need on Tangent Sections

Note:
For supporting length of need equation factors, see Exhibit 1610-6

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Exhibit 1610-6 Barrier Length of Need

Design Parameters
ADT Barrier Type
Posted
Rigid &
Speed Rigid
Over 5,000 to 1,000 to Under Rigid Semi-rigid
(mph) Unrestrained
10,000 10,00 4,999 1,000 Anchored Barrier
Barrier
Barrier
LR (ft) LR (ft) LR (ft) LR (ft) F F F
70 360 330 290 250 20 18 15
65 330 290 250 225 20 18 15
60 300 250 210 200 18 16 14
55 265 220 185 175 16 14 12
50 230 190 160 150 14 12 11
45 195 160 135 125 12 11 10
40 160 130 110 100 11 10 9
35 135 110 95 85 11 10 9
30 110 90 80 70 11 10 9
25 110 90 80 70 11 10 9
L1 = Length of barrier parallel to roadway from adjacent-side fixed feature to beginning of barrier flare. This is
used if a portion of the barrier cannot be flared (such as a bridge rail and the transition).
L2 = Distance from adjacent edge of traveled way to portion of barrier parallel to roadway.
L4 = Length of barrier parallel to roadway from opposite-side fixed feature to beginning of barrier flare.
L5 = Distance from centerline of roadway to portion of barrier parallel to roadway. Note: If the fixed feature is
outside the Design Clear Zone when measured from the centerline, it may only be necessary to provide a
crash-tested end treatment for the barrier.
LH1 = Distance from outside edge of traveled way to back side of adjacent-side fixed feature.
Note: If a fixed feature extends past the Design Clear Zone, the Design Clear Zone can be used as LH1.
LH2 = Distance from centerline of roadway to back side of opposite-side fixed feature. Note: If a fixed feature
extends past the Design Clear Zone, the Design Clear Zone can be used as LH2.
LR = Runout length, measured parallel to roadway.
X1 = Length of need for barrier to shield an adjacent-side fixed feature.
X2 = Length of need for barrier to shield an opposite-side fixed feature.
F = Flare rate value.
Y = Offset distance needed at the beginning of the length of need.
Different end treatments need different offsets:
 For the SRT 350 and FLEAT 350, use Y = 1.8 feet.
 For evaluating existing BCTs, use Y = 1.8 feet.
 For the FLEAT TL-2, use Y = 0.8 feet.
 No offset is needed for the non-flared terminals or impact attenuator systems. Use Y = 0.

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Exhibit 1610-7 Barrier Length of Need on Curves

Notes:
 This is a graphical method for determining the length of need for barrier on the
outside of a curve.
 On a scale drawing, draw a tangent from the curve to the back of the fixed feature.
Compare T to LR from Exhibit 1610-6 and use the shorter value.
 If using LR, follow Exhibits 1610-5 and 6.
 If using T, draw the intersecting barrier run to scale and measure the length of
need.

Exhibit 1610-8 W-Beam Guardrail Trailing End Placement for Divided Highways

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1610.03(6) Barrier Delineation

Refer to Chapter 1030 for barrier delineation requirements.

1610.04 Beam Guardrail

Strong post W-beam guardrail and thrie beam guardrail are semi-rigid barriers used
predominantly on roadsides. They have limited application as median barrier. A strong-post
W-beam (commonly referred to as W-Beam) guardrail system is the most common type of
guardrail system used. The design uses wood or steel posts, rail, and blockouts to support
the rail away from the post. The system resists a vehicle impact through a combination of the
tensile and flexural stiffness of the rail and the bending or shearing resistance of the post.

Installed incorrectly, strong post W-beam guardrail can cause vehicle snagging or spearing.
This can be avoided by lapping the rail splices in the direction of traffic (as shown in the
Standard Plans), by using crash-tested end treatments, and by blocking the rail away from
the posts.

Beam guardrail systems are shown in the Standard Plans.

1610.04(1) Beam Guardrail Systems

1610.04(1)(a) Type 31 Beam Guardrail
Use Type 31 guardrail for new installations. The Type 31 system uses many of the same
components as the old WSDOT Type 1 system. The main differences are that the blockouts
extend 12 inches from the posts, the rail height is 31 inches from the ground to the top of
the rail, the deflection requirements are 2 feet greater, and the rail elements are spliced
between posts.

Type 31 guardrail offers tolerance for future HMA overlays. The system allows a 3-inch
tolerance from 31 inches to 28 inches without adjustment of the rail element.

Type 31 guardrail is available double-sided, which can be used in medians.

1610.04(1)(b) (Old) Type 1 Beam Guardrail

Previous WSDOT standard practice was to install W-beam guardrail at a rail height of 27 to
28 inches, and is referred to as “Type 1” guardrail. WSDOT is phasing out the use of Type 1
guardrail. Do not use Type 1 guardrail for new installations, except when the Type 1 guardrail
weak post system is the best choice at an intersection due to site constraints (see
1610.04(7)(a)). Place new objects a minimum of 5 feet behind the face of existing beam
guardrail type 1. For more information on (Old) Beam Guardrail Type 1, see:
 http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm.

Existing runs of Type 1 guardrail are acceptable to leave in place. If an existing run of Type 1
guardrail requires extending, use the Beam Guardrail Type 31 to Beam Guardrail Type 1
Adaptor shown in the Standard Plans, and complete the guardrail extension using Type 31
guardrail.

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1610.04(1)(c) Other Guardrail Types

W-beam guardrail Type 2 and Type 3 have a height of 30 inches and utilize a rubrail. A rubrail
is a structural steel channel added below the W-beam rail and is used in these specific
designs to reduce vehicle snagging on the post. Existing runs of Type 2 or Type 3 guardrail are
acceptable to leave in place. If the existing run of Type 2 or 3 requires extending contact
WSDOT Design Office to identify appropriate extension methods.

Type 4 guardrail is a double-sided version of the Type 1 guardrail system. For new
installation, use the Type 31 double-sided w-beam guardrail instead of Type 4 guardrail.
Existing runs of Type 4 guardrail are acceptable to leave in place. If the existing run of Type 4
requires extending contact WSDOT Design Office to identify appropriate extension methods
to transition to the Type 31 double-sided system.

Type 10 and Type 11 are thrie-beam guardrail systems. Existing runs of Type 10 or 11
guardrail are acceptable to leave in place. If an existing run of Type 10 or Type 11 guardrail
requires extending, contact the WSDOT Design Office to discuss options.

Weak post W-beam guardrail (Type 20) and thrie beam guardrail (Type 21) are flexible
barrier systems primarily used in conjunction with a Service Level 1 bridge rail system for
bridges with timber decks. These systems use weak steel posts. For information on Type 20
and Type 21 guardrail see:  http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm

1610.04(2) Beam Guardrail Placement

There a number of considerations regarding guardrail placement. These include:
 During the project development processes, consult with maintenance staff to help
identify guardrail runs that may need to be modified.
 When existing Type 1 guardrail is replaced by Type 31 guardrail along existing
shoulders with a width greater than 4 feet (5 feet for bicycles), the shoulder width
may be reduced by 4 inches to accommodate the 12-inch blockout. A Design
Analysis is not required for the reduced shoulder width. If the remaining shoulder
width is 4 feet or less, see Chapter 1030 for barrier delineation guidance.
 Keep the slope of the area between the edge of the shoulder and the face of the
guardrail 10H:1V or flatter.
 Type 31 or Type 1 beam guardrail can be placed anywhere outside of the shoulder
on fill slopes 10:1 or flatter,.
 Type 1 beam guardrail can be placed on fill slopes between 6H:1V and 10H:1V at
the slope break point of the shoulder or at least 12 feet from the slope breakpoint.
This placement case does not apply to Type 31 beam guardrail.
 Do not place Type 31 or Type 1 beam guardrail with standard length posts on a fill
slope steeper than 6H:1V. See Exhibit 1610-9 for allowable placement exceptions
on fill slopes steeper than 6H:1V using long post beam guardrail.
 On the high side of superelevated sections, place beam guardrail at the edge of
shoulder prior to the slope breakpoint.
 For W-beam guardrail installed at or near the shoulder, 2 feet of widening behind
the barrier is generally provided from the back of the post to the slope breakpoint

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of a fill slope (see Exhibit 1610-9, Case 2). If the slope is 2H:1V or flatter, this
distance can be 2.5 feet measured from the face of the guardrail rather than the
back of the post (see Exhibit 1610-9, Case 1).
 On projects where no roadway widening is proposed and site constraints prevent
providing the 2-foot shoulder widening behind the barrier, long post installations
are available as shown in Exhibit 1610-9, Cases 3, 4, 5, and 6. When installing
guardrail where the roadway is to be widened or along new alignments, the use of
Cases 5 and 6 requires a Design Analysis.

Exhibit 1610-9 Beam Guardrail Post Installation

Notes:
 Use Cases 1 and 3 when there is a 2.5-foot or greater shoulder widening from face
of guardrail to the slope breakpoint.
 Use Case 2 when there is a 4.0-foot or greater shoulder widening from the face of
the guardrail to the slope breakpoint.
 Use Cases 4, 5, and 6 when there is less than a 2.5-foot shoulder widening from face
of guardrail to the slope breakpoint.
 Cases shown do not apply to terminals, transition sections or anchors. Install
terminals, transition sections and anchors per the Standard Plans.

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1610.04(3) W-Beam Barrier Height

See Chapter 1120 when evaluating guardrail system height on Preservation (P1, P2, P3)
projects.

For other projects requiring evaluation of guardrail (see Section 1105.02(1)), evaluate the
guardrail system height as follows:
 For existing Type 1 guardrail with heights falling outside the range from 26.5 inches
to 31 inches, adjust or replace the rail to a minimum height of 28 inches up to a
maximum height of 30 inches, or replace the run with 31-inch-high Type 31 beam
guardrail.
 For existing Type 31 guardrail runs with heights falling outside the range of 28 to 32
inches, adjust or replace the rail to a height of 31 inches, or replace the run with a
new run of 31-inch-high Type 31 beam guardrail.

For Type 1 and Type 31 standard run W-beam guardrail, the blockout and rail element may
be raised up to 4 inches by field drilling a new hole in the guardrail post. Verify that the
condition of the posts and blockouts are suitable for raising in this manner. If not, the post or
block will need to be replaced. See the Standard Plans.

If Type 1 Alternative W-beam guardrail is present, the blockout and rail element may be
raised after each overlay by using the pre-drilled holes in the guardrail posts.

See Section 1610.04(5) for information on adjusting the height of guardrail terminals.

1610.04(4) Additional Guidance

Additional guidance related to w-beam guardrail:
 Crossroad and driveway locations cause gaps in the guardrail creating situations
requiring special consideration. The preferred solutions are either to eliminate the
need for the barrier, or realign the crossroad or driveway to accommodate the
necessary guardrail run length. Alternatively, an intersection design guardrail
system can be installed at the intersection. See 1610.04(7)(a) for more information.
At these locations, a barrier flare might be needed to provide sight distance.
 Snowload post and rail washers are not used in new guardrail installations or
guardrail terminal installations. Snowload post and rail washers installed on existing
guardrail installations may remain in place except when the rail element is removed
from post for any reason. If this occurs, remove and discard the snowload post and
rail washers before reassembling the guardrail components.
 In most cases, the use of curb in conjunction with beam guardrail is discouraged.
When a curb is needed place the curb as follows:
o For Type 1 W-beam guardrail, a 3-inch high curb is preferred and it is
placed flush with the face of rail or placed behind the face of the rail. The
3-inch high curb can be used for any posted speed. If necessary, a 4-inch
high extruded curb is placed flush with the face of rail or placed behind
the face of the rail and can be used for any posted speed. Finally, a 6-
inch high extruded curb is placed flush with the face of rail or placed
behind the face of the rail and can be used where the posted speed is 50

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mph or below. When replacing extruded curb at locations where the

posted speed is above 50 mph, use 3-inch high or 4-inch high curb. (See
the Standard Plans for extruded curb designs.)
o For Type 31 W-beam guardrail, a 3-inch, 4-inch, or 6-inch curb is placed
flush with the face of rail or placed behind the face of the rail and can be
used for any posted speed. Use the shortest height curb possible. An
acceptable option is to place up to a 6-inch-high extruded curb at a
maximum 6 inch offset in front of the rail face at any posted speed.
Contact the WSDOT Design Office for more information.
 Guardrail posts should be able to rotate when the rail is impacted. When installing
strong post W-beam guardrail posts in a rigid surface such as asphalt or concrete
pavement, use leave-outs. Leave-outs are areas around the post that has no rigid
material, which allows the post to rotate. Contact the WSDOT Design Office for
more information.
 For (Old) Guardrail Types 1, 2, 3, and 4, it is acceptable to use blockouts that extend
the rail element from the post for a distance not to exceed 16 inches.
 Where it is not feasible to install a post on a Type 31 system (i.e. utility or drainage
conflict), one post may be omitted every 56.25 feet (9th post), except that an
omitted post must be a minimum of 75 feet from an anchorage post, a minimum of
35 feet from the beginning of a thrie beam transition, and a minimum of 35 feet
from the point where a terminal system joins the standard run.
o Do not omit posts in guardrail runs with posts placed less than 2 feet
from the slope break point. Guardrail runs with omitted posts must have
at least 2 feet of 10:1 or flatter embankment behind them as shown in
DM Exhibit 1610‐10 Case 2.
o Do not omit posts where curb is in front the guardrail.
o Consult HQ Design for acceptable conditions to omit single posts in
guardrail runs with 12’ – 6”, 18’ – 9”, or 25’ – 0” span systems (see Std.
Plan C‐20.40) placed within the run.
o List all the locations of omitted posts in the project plans to ensure that
posts are omitted following the conditions described in this section.
 In locations where shallow fill depth prevents the installation of standard length
guardrail posts (i.e. box culverts, drainage), guardrail can be spanned over the
location or be attached to the top of the structure (see standard plans). Other
shallow fill designs are available. Contact HQ Design for more information about
these alternative designs.

1610.04(5) Terminals and Anchors

A guardrail anchor is required at the end of a run of guardrail to develop tensile strength
throughout its length. In addition, when the end of the guardrail is subject to head-on
impacts, a crash-tested guardrail terminal is required (see the Standard Plans).

See Chapter 1120 for guidance regarding the evaluation of terminals on Preservation
projects (P1, P2, and P3).

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For other projects requiring evaluation of terminals (see Section 1105.02(1)), evaluate the
terminals as follows:

Replace guardrail terminals that do not have a crash-tested design with MASH compliant
crash-tested guardrail terminals. Common features of systems that do not meet current
crash-tested designs include:
 No cable anchor.
 A cable anchored into concrete in front of the first post.
 Second post not breakaway (CRT).
 Design A end section.
 Design C end sections may be left in place if the terminal is otherwise a crash-tested
design —see the Standard Plans for end section details.
 Terminals with beam guardrail on both sides of the posts (two-sided).
 Buried guardrail terminals that slope down such that the guardrail height is reduced
to less than 28 inches (measured in relation to a 10H:1V line extended from the
breakpoint at edge of shoulder).

When the height of a terminal or anchor, as measured from the ground to the top of the rail
element, will be affected by the project, adjust the terminal or anchor based upon the
following criteria:
 If the height of the terminal or anchor adjoining Types 1, 2, 3, or 4 guardrail will be
reduced by the project to be less than 26.5 inches or increased to greater than 30
inches, adjust the height of the terminal to a minimum of 28 inches and a maximum
of 30 inches. A terminal height of 30 inches is desirable to accommodate future
overlays.
 If the height of the terminal or anchor adjoining Type 31 guardrail will be reduced
by the project to be less than 28 inches or increased to greater than 32 inches,
adjust the height to 31 inches.
 When adjusting terminals that are equipped with CRT posts, the top-drilled holes in
the posts need to remain at the surface of the ground.
 When adjusting the height of a terminal or anchor, adjust it by raising the posts of
the terminal or anchor and tamping the ground around the posts to prevent
settlement of the raised posts. Note: do not raise the blockouts or rail of the
terminal or anchor by drilling new holes in the terminal posts.

One terminal that was used extensively on Washington’s highways was the Breakaway Cable
Terminal (BCT). This system used a parabolic flare similar to the Slotted Rail Terminal (SRT)
and a Type 1 anchor (Type 1 anchor posts are wood set in a steel tube or a concrete
foundation). For guidance regarding BCT’s and other terminals on Preservation projects see
Chapter 1120. For non-Preservation projects, replace BCTs with a currently approved
terminal using the following guidance:

 Verify length of need, and adjust the terminal location as required.

 Replace adjacent transition sections that are not compliant with 1610.04(6).

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 Transition from Type 1 to Type 31 using the adaptor (Standard Plan C‐25.80) where
required.

 Raise or replace the entire run if engineering judgement indicates that it is prudent
for that situation.

 Use the grading criteria shown on the terminal standard plans (C‐22.40 or C‐22.45).
When using existing grading, check to see that it complies with the grading criteria
shown on the current terminal standard plans.

 Remove curbs from in front of terminals if hydraulically acceptable.

Information regarding (Old) Type 1 beam guardrail terminals can be found at:
 http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm

1610.04(5)(a) Buried Terminal (BT) for Type 31 Beam Guardrail

A buried terminal is designed to terminate the guardrail by burying the end in a backslope.
The BT is the preferred terminal because it eliminates the exposed end of the guardrail.

For new BT installations, use the Buried Terminal Type 2. Previously, another BT option (the
Buried Terminal Type 1) was an available choice. For existing installations, it is acceptable to
leave this option in service as long as height requirements and other design criteria is met.
See the plan sheet at:  www.wsdot.wa.gov/design/standards/plansheet.

The BT uses a Type 2 anchor to develop the tensile strength in the guardrail. The backslope
needed to install a BT is to be 3H:1V or steeper and at least 4 feet in height above the
roadway. The entire BT can be used within the length of need for backslopes of 1H:1V or
steeper if the barrier remains at full height in relation to the roadway shoulder to the point
where the barrier enters the backslope.

For backslopes between 1H:1V and 3H:1V, design the length of need beginning at the point
where the W-beam remains at full height in relation to the roadway shoulder—usually
beginning at the point where the barrier crosses the ditch line. If the backslope is flatter than
1H:1V, provide a minimum 20-foot-wide by 75-foot-long clear area that is free of fixed
features behind the barrier and between the beginning length of need point at the terminal
end to the mitigated object to be protected.

Flare the guardrail to the foreslope/backslope intersection using a flare rate that meets the
criteria in 1610.03(4). Provide a 4H:1V or flatter foreslope into the face of the guardrail and
maintain the full guardrail height to the foreslope/backslope intersection in relation to a
10H:1V line extending from edge of shoulder breakpoint. (See the Standard Plans for details.)

1610.04(5)(b) Non-flared Terminals for Type 31 Beam Guardrail

If a buried terminal cannot be installed as described in 1610.04(5)(a), install a non-flared
terminal. These systems use W-beam guardrail with a special end piece that fits over the end
of the guardrail. When hit head on, the end piece is pushed over the rail, absorbing the
energy of the impacting vehicle in the process. An anchor is included for developing the
tensile strength of the guardrail. The length of need does not begin at the impact head, but
will vary by system. Non-flared terminals may be provided for two different design levels that
are based on the posted speed of the highway. For highways with a posted speed of 50 mph

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or above, use only a TL-3 (Test Level 3) product. For highways with a posted speed of 45 mph
or below, either a TL-2 or a TL-3 product is acceptable. See the Standard Plans.

The availability and acceptance of these systems is expected to change rapidly over time.
Refer to the Type 31 Beam Guardrail Terminals website for the latest information on
availability or acceptance of different systems (see
 http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm).

Although non-flared terminals do not need to have an offset at the end, a flare is
recommended so that the end piece does not protrude into the shoulder. See the Standard
Plans.

Four feet of additional widening behind the terminal is needed at the end posts to properly
anchor the systems (See the Standard Plans). When widening includes an embankment,
properly placed and compacted fill material will be necessary for optimum terminal
performance (see the Standard Specifications for embankment widening for guardrail).

For Type 31 non-flared terminals, no additional embankment widening is required at the

terminal when installed on slopes 10:1 or flatter.

No snowload rail washers are allowed within the limits of these terminals.

WSDOT does not currently use a flared terminal system for the Type 31 guardrail system.

Note: Approved shop drawings for terminals can be found by accessing the following
website:  http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm

1610.04(5)(c) Terminal Evolution Considerations

Some currently approved terminals have been in service for a number of years. During this
time, there have been minor design changes. However, these minor changes have not
changed the devices’ approval status. Previous designs for these terminals may remain in
place.

Note: If questions arise concerning the current approval status of a device, contact the HQ
Design Office for clarification when replacement is being considered.
1610.04(5)(d) Anchors
A guardrail anchor is needed at the end of a run of guardrail to develop tensile strength
throughout its length.
 Use the Type 10 anchor to develop the tensile strength of the guardrail on the end
of Type 31 guardrail runs where a crash-tested terminal is not needed.
 A Type 2 anchor is used with the buried terminal.

For information on anchor types used in runs of (Old) Beam Guardrail Type 1, see:
 http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm.

1610.04(6) Transitions and Connections

When there is an abrupt change from one barrier type to a more rigid barrier type, a vehicle
hitting the more flexible barrier may be caught in the deflected barrier pocket and directed

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Traffic Barriers Chapter 1610

into the more rigid barrier. This is commonly referred to as “pocketing.” A transition stiffens
the more flexible barrier by decreasing the post spacing, increasing the post size, and using
stiffer beam elements to reduce the possibility of pocketing.

When connecting beam guardrail to a more rigid barrier or a structure use the transitions
and connections that are shown in Exhibits 1610-10 and 1610-11 and detailed in the
Standard Plans. Verify the length of need (see 1610.03(5)) when designing transitions,
particularly transitions between beam guardrail or end terminals to bridge structures.

Type 21 transitions can be used on highways with all posted speeds to connect w-beam
guardrail to single slope, safety shape or vertical concrete barriers.

Type 22 and Type 23 transitions are used to connect w-beam guardrail to thrie beam on
bridges.

Type 24 transitions can be used on highways with a posted speed of 45 mph or less to
connect w-beam guardrail to single slope, safety shape or vertical concrete barriers.

When connecting a Type 21 or Type 24 Transition to an existing vertical faced bridge rail with
a low parapet, a special connection plate may be required. Coordinate with the WSDOT
Bridge and Structures Office (BSO). The transition pay item includes the connection.

Install transitions on 10:1 or flatter slopes with the 10:1 or flatter slope extending a minimum
of 2 feet behind the guardrail transition post similar to what is shown in DM Exhibit 1610-9
Placement Case 2.

For information regarding transitions used with (Old) Type 1 guardrail see:
http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm.

Exhibit 1610-10 Guardrail Connections

Condition Connection
Unrestrained precast concrete barrier A
Rigid, rigid anchored, untapered safety shape bridge rails or barriers [1] B
Bridge rails with curbs 9 inches or less in width B
Bridge rails with curbs between 9 and 18 inches wide C
Vertical walls, single slope bridge rail or concrete barrier, or tapered safety
D
shape barrier [1]
All bridge rail and concrete barrier types located on trailing ends of one-way
F
roadways

Note:
[1] New single slope and safety shape bridge rails are designed with the toe of the barrier
tapered so that it does not project past the face of the approach guardrail.

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Exhibit 1610-11 Transitions and Connections

Transition
Connecting Type 31 W-Beam Guardrail to: Connection
Type*
New Installation 21, 24 [3] D
Concrete Parapet > (Greater Than) 20 in. 21, 24 [3] Exh. 1610-10 [2]
Existing Concrete
Concrete Parapet < (Less Than) 20 in. 21, 24 [3] Exh. 1610-10 [2]
Bridge Rail [1] Thrie Beam at Face Approach End 23 n/a
of Curb Trailing End (two-way traffic only) 23 n/a

Thrie Beam at Bridge Approach End 22 n/a

Rail (curb exposed) Trailing End (two-way traffic only) 22 n/a

Concrete Rigid & Rigid Anchored 21, 24 [3] Exhibit 1610-10

Barrier Unrestrained 21, 24 [3] A

Transition
Connecting Thrie Beam Guardrail to: Connection
Type*
Bridge Rail or
Concrete See the thrie beam transition in the Plan Sheet Library Exhibit 1610-10
Barrier

*Consult Section C of the Standard Plans for details on transition types.

Notes:
[1] For Service Level 1 bridge rail,
see: http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm., Type 1 Beam Guardrail
Placement Cases, Placement Case 14.
[2] When connecting a Type 21 or Type 24 Transition to an existing vertical faced bridge rail with a low
parapet, a special connection plate may be required. Contact the WSDOT BSO for details.
[3] Transition Type 21 is acceptable for use on highways with all posted speeds. Transition Type 24 is
acceptable for use on highways with posted speeds 45 mph or below.

1610.04(7) Guardrail Placement Cases

The Standard Plans and Plan Sheet Library contain placement cases that show beam
guardrail elements needed for typical situations. For new installations, use the appropriate
Type 31 placement option (except as noted below).

Information regarding placement cases for (Old) Type 1 beam guardrail can be found at
 http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm.

1610.04(7)(a) Beam Guardrail Placement Cases

 Case 1-31 is used where there is one-way traffic. It uses a crash-tested terminal on
the approach end and a Type 10 anchor on the trailing end.
 Case 2-31 is used where there is two-way traffic. A crash-tested terminal is used on
both ends.

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 Case 3-31 is used at railroad signal supports on one-way or two-way roadways. A

terminal is used on the approach end, but usually cannot be used on the trailing
end because of its proximity to the railroad tracks. If there is a history of crossover
collisions, consider additional protection such as an impact attenuator.
 Case 4-31 is used where guardrail on the approach to a bridge is to be shifted
laterally to connect with the bridge rail. A terminal is used on the approach end and
a transition is needed at the bridge end. Curves (bends) are shown in the guardrail
to shift it to the bridge rail. However, the length of the curves are not critical. The
criterion is to provide smooth curves that are not more abrupt than the allowable
flare rate (see Exhibit 1610-4).
 Case 5-31 is a typical bridge approach where a terminal and a transition are needed.
 Case 10 (A-31, B-31, and C-31) is used at roadside fixed features (such as bridge
piers) when 5 or more feet are available from the face of the guardrail to the
feature. The approach end is the same for one-way or two-way traffic. Case 10A-31
is used with two-way traffic; therefore, a terminal is needed on the trailing end.
Case 10B-31 is used for one-way traffic when there is no need to extend guardrail
past the bridge pier and a Type 10 anchor is used to end the guardrail. Case 10C-31
is used for one-way traffic when the guardrail will extend for a distance past the
bridge pier.
 The Beam Guardrail Type 31 Placement 12'-6", 18'-9", or 25'-0” Span design is used
when it is necessary to omit one, two, or three posts. This application is typically
used when guardrail is installed over a shallow buried obstruction, such as drainage
structures. This design may be used in other situations where there are no above
ground objects located behind the guardrail and within the lateral deflection
distance. Three CRT posts are provided on each end of the omitted post(s). Type 31
guardrail (including terminals and anchors) must extend at least 62.5 feet (10 posts)
upstream and downstream from the ends of the outer CRT posts (furthest from
obstruction) in order for the guardrail system to function as designed during a
vehicle crash. Also, this guardrail design has specific grading requirements, see
applicable standard plan. Note: This guardrail design may require fall protection.
See Section 730.04(7)(b) for worker fall protection requirements. See Section
1510.15(3) for pedestrian fall protection requirements. When a fall protection
system is located within the deflection zone of the barrier system, contact HQ
Design for options.
 Guardrail Placement at intersections – Two solutions are currently available for use
where bridge ends or similar conditions exist in close proximity to a roadway
intersection or driveway. These designs are used at crossroads or road approaches
where a barrier is needed and where the length of need cannot be achieved using
standard components such as standard longitudinal barrier runs, transitions, and
terminals. The “Strong Post Intersection Design” uses Type 31 guardrail and is
available for use in new installations. A “Weak Post Intersection Design,” which uses
Type 1 guardrail, is available and may also be used in new installations (see
1610.04(1)(b)).
 Type 31 guardrail placement with less than 5-feet from face of guardrail to a fixed
or breakaway object – There may be instances where Type 31 beam guardrail
cannot be placed at least 5-feet from the face of rail to the front edge of an object

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which does not meet the minimum deflection distance of the Type 31 guardrail
system. Contact HQ Design to discuss barrier placement options when this occurs.

1610.05 High-Tension Cable Barrier

Cable barrier is a flexible barrier system that can be used on a roadside or as a median
barrier. Early cable barrier designs centered around low-tension cable systems. With
research and crash analysis of these systems, the designs evolved into high-tension cable
systems. These high-tension cable systems are primarily used in medians and are preferred
for many installations due in part to high benefit-to-cost ratios. Read about advantages for
selecting a cable barrier system here:
 http://www.wsdot.wa.gov/publications/fulltext/design/Policy/CableBarriers.pdf.

There are a number of manufacturers of high-tension cable barrier systems. These systems
have been designed using either three or four-cables fixed to metal posts placed at a fixed
spacing. Each cable system has specially designed anchors placed at both ends of the barrier
run to provide the proper tensioning in the cables. Currently, both three and four-cable high-
tension cable barrier systems are installed along WSDOT state routes. See additional
information about these approved cable barrier systems here:
 http://www.wsdot.wa.gov/publications/fulltext/design/Policy/CableBarriers.pdf.

Use four-cable high-tension cable barrier systems for all new installations.

1610.05(1) High-Tension Cable Barrier Placement

High-tension cable barrier can be placed in a median or along the roadside.

Note: Additional placement cases are shown in the WSDOT Standard Plans. For non-typical
installations, such as double runs of cable barrier or median ditch cross sections that differ
significantly from those shown, contact the HQ Design Office for guidance.

1610.05(1)(a) Median Applications

For typical cable barrier installations in a median, the following apply (see Exhibit 1610-12a):
 Install the cable barrier as far from the edge of traveled way as site constraints
allow. Consider a minimum placement distance of 8 feet from the edge of traveled
way to allow vehicles to use this area for refuge.
 Install cable barrier on slopes 6H:1V or flatter.
 There are approved high-tension cable barrier systems that can be placed on slopes
as steep as 4H:1V. The use of these systems requires special placement
considerations, contact the HQ Design Office for guidance.
 Provide an obstruction free zone within the cable barrier system’s lateral deflection
distance (see 1610.05(2)).
 On tangent sections of a roadway where no ditch is present, consider installing the
cable barrier in the middle of the median. See Exhibit 1610-12a.
 Along horizontal curves, consider installing the cable barrier along the inside of the
curve. Reduce the post spacing per manufacturer’s recommendations.
 In medians with ditches, install the cable barrier as follows (See Exhibit 1610-12a):

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o The preferred location is to install the cable barrier at an 8-foot or

greater offset from the ditch centerline.
o Alternatively, the cable barrier can be installed at the centerline of the
ditch out to a 1-foot offset either side of the ditch centerline. While
permissible, this is not the preferred area to install cable barrier due to
the potential of post scour, possible interference with drainage
structures, and maintenance concerns.
o Do not install cable barrier in the area between 1-foot to 8-foot offset
from the ditch centerline to avoid “under-riding” of vehicles crossing the
ditch.
 In some situations, it may be advantageous to terminate a run of cable barrier on
one side of the median (to provide maintenance access to a feature, for example)
and then begin an adjacent cable barrier run on the opposite side of the median. In
this application, it is important to provide adequate cable barrier overlap distance
between the two runs. For placement guidance, see Exhibit 1610-13a.
 Narrow medians provide little space for maintenance crews to repair or reposition
the barrier. Wherever site conditions permit, provide at least 14 feet of clearance
from the adjacent lane edge to the face of the cable barrier.

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Exhibit 1610-12a Median Cable Barrier Placement

Notes:

1 Cable barrier may be installed at an 8-foot or greater offset from centerline

(preferred placement), or it may be installed in the center of the ditch out to a 1-
foot offset from the ditch centerline (left or right).

2 Avoid installing cable barrier in the area between 1-foot to 8-foot offset from the
ditch centerline (left or right).

Provide an obstruction free zone within the cable barrier’s lateral deflection
3
distance, and provide sufficient lateral barrier deflection distance to prevent a

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Traffic Barriers Chapter 1610

vehicle’s encroachment into the opposite lane of travel. See 1610.05(2) for more
information.

1610.05(1)(b) Roadside Applications

For typical non-median roadside applications, the following apply:
 Install the cable barrier as far from the edge of traveled way as site constraints
allow.
 Consider a minimum placement distance of 8 feet from the edge of traveled way to
allow vehicles to use this area for refuge.
 Install cable barrier on slopes 6H:1V or flatter
 There are approved high-tension cable barrier systems that can be placed on slopes
as steep as 4H:1V. The use of these systems requires special placement
considerations, contact the HQ Design Office for guidance.
 Along horizontal curves, consider installing along the inside of the curve. Reduce
post spacing per manufacturer’s recommendations
 Provide an obstruction free zone within the cable barrier system’s lateral deflection
distance, see 1610.05(2).

Exhibit 1610-12b Roadside Cable Barrier Placement

Notes:

1 Provide an obstruction free zone within the cable barrier’s lateral deflection
distance, see Section 1610.05(2)

1610.05(2) High-Tension Cable Barrier Lateral Deflection Distances

Depending on the high-tension cable barrier system, lateral deflection distances for each
barrier system vary based upon the length of the barrier run, the spacing of the end anchors,
and post spacing. Provide an obstruction free zone within the system’s lateral deflection
distance for the following situations:

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In the direction of travel (located in the median or along roadside), locate the cable barrier
system so that there are no fixed objects within the limits of the cable barrier lateral
deflection distance.

For opposing traffic (where present), locate the cable barrier to provide lateral deflection
distance to prevent a vehicle’s encroachment into the opposite lane of travel.

Low–tension cable barrier systems require 12 feet of lateral deflection. Use high-tension
cable barrier systems in new cable barrier installations. High-tension barrier systems have
lateral deflection distances between 6 to 10 feet. Specify the maximum allowable lateral
deflection distance in the contract documents in order for the contractor to select a cable
barrier manufacturer that meets the lateral deflection requirements.

Note: There are new high-tension cable barrier systems under development that may change
selection and placement criteria. For example, newer systems may allow placement on
steeper slopes or have reduced deflection distances. Contact the HQ Design Office for
guidance.

1610.05(3) High-Tension Cable Barrier Termination

Manufacturers of high-tension four-cable barrier systems provide designed anchors for the
ends of cable barrier runs. Whenever practicable, locate high-tension cable barrier terminals
in areas where they are least likely to be hit by errant vehicles (e.g. located outside clear
zone, located behind another barrier system).

Often, high-tension cable barrier systems will overlap/interface with a stiffer barrier system
(typically beam guardrail but can be concrete barrier). When terminating a cable barrier run
to begin a beam guardrail run, there are essentially four choices for the overlap/interface of
the two barrier systems (contact HQ Design when terminating a cable barrier run to begin a
concrete barrier run). The four choices are:

Connect Cable Barrier to Beam Guardrail: This placement connects the cable barrier directly
onto the beam guardrail runs (such as cable barrier connected to beam guardrail transitions
coming off bridge rails) or to a different cable barrier anchorage system.

When connecting cable barrier onto beam guardrail, the guardrail must continue at least 75
feet downstream from the point where the cable barrier attaches to the beam guardrail, or
the beam guardrail needs to be connected to a stiffer system (i.e. bridge rail, concrete
barrier) to reduce the chance of beam guardrail posts pulling out of the ground from the
tension in the cable barrier system. When terminating cable barrier in this manner; review
field conditions, check local maintenance personnel needs, and specify the required
connection option in the contract documents.

When cable barrier is connected directly to a more rigid barrier, a transition section is
typically needed. Contact the HQ Design Office for further details.

Install Cable Barrier Behind Beam Guardrail: This placement terminates the cable barrier
behind the beam guardrail system. Ensure the lateral distance between the two barrier
systems exceeds the deflection distance of the beam guardrail system placed in front of the
cable barrier system. This will reduce the chances of having the two barrier systems

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interfering with each other during a vehicle impact, or having an errant vehicle rebound off
the cable barrier into the back of the beam guardrail during a vehicle impact. Exhibit 1610-
13b shows an example of terminating cable barrier behind a beam guardrail system.

Install Cable Barrier in Front of Beam Guardrail: This placement terminates the cable barrier
in front of the beam guardrail system. Ensure that the standard run of cable barrier extends
to, or past, the Length of Need post of the beam guardrail terminal, and provide a minimum
lateral distance of 4-feet between the two barrier systems. This will reduce the chances of
having the two barrier systems interfere with each other during a vehicle impact. Exhibit
1610-13b shows an example of terminating cable barrier in front of a beam guardrail system.

Terminate Cable Barrier in Advance of Beam Guardrail: This placement terminates the cable
barrier in advance of the beam guardrail system. This placement leaves a gap in guardrail
coverage and can be a maintenance concern if both terminals are hit by an errant vehicle.
However, this placement can be used when side slope grades become an issue (i.e. slope is
too steep to place cable barrier or beam guardrail, slope widening requires large amounts of
fill to accommodate barrier systems). Exhibit 1610-13b shows an example of terminating
cable barrier in advance of a beam guardrail system.

Exhibit 1610-13a Cable Barrier Placement: Overlap on Divided Highways

Cable Barrier Median Overlap

𝐿𝐻1−𝐿2
𝐵𝑂 = 𝐿𝐻1 (Direction A shown)
𝐿𝑅

Notes:

[1] Calculate barrier overlap (BO) from both directions of travel. Use the greatest value
of BO obtained.

[2] For supporting length of need equation factors, see Exhibit 1610-6.

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Exhibit 1610-13b Cable Barrier Placement: Cable Barrier Termination/Overlap with Beam
Guardrail

LH1 − L2
BO =
LH1/LR

Cable Barrier Termination: Install Behind Beam Guardrail

Cable Barrier Termination: Install in Front of Beam Guardrail

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Exhibit 1610-13b Cable Barrier Placement: Cable Barrier Termination/Overlap with Beam
Guardrail (cont)

Cable Barrier Termination: Terminate In Advance of Beam Guardrail

Notes:
These barrier placements can be placed in both roadside and medians.

[1] The beam guardrail may need to be extended and flared in advance of a cable barrier
terminal to maintain adequate barrier overlap, lateral offset distance between
barrier systems, and shoulder width.

[2] Typical applications may be at either bridge transitions or where high-tension cable
and beam guardrail systems end or begin.

[3] For supporting length of need equation factors, see Exhibit 1610-6.

1610.05(4) High-Tension Cable Barrier Curb Placement

Avoid the placement of curb in conjunction with high-tension cable barrier systems.
Currently, there are no known acceptable cable barrier systems that have been successfully
crash tested with this feature present.

1610.06 Concrete Barrier

Concrete barriers are identified as either rigid, rigid anchored, or unrestrained rigid systems.
They are commonly used in medians and as shoulder barriers. These systems are stiffer than
beam guardrail or cable barrier, and impacts with these barriers tend to be more severe.
Consider the following when installing concrete barriers:
 For slopes 10H:1V or flatter, concrete barrier can be used anywhere outside of the
shoulder.
 Do not use concrete barrier at locations where the foreslope into the face of the
barrier is steeper than 10H:1V.
 Light standards mounted on top of precast concrete median barrier must not have
breakaway features. (See the concrete barrier light standard section in the Standard
Plans.)
 When considering concrete barrier use in areas where drainage and environmental
issues (such as stormwater, wildlife, or endangered species) might be adversely

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impacted, contact the HQ Hydraulics Office and/or the appropriate environmental

offices for guidance. Also, refer to 1610.02.

1610.06(1) Concrete Barrier Shapes

Concrete barriers use a single-slope or safety shape (New Jersey or F-Shape) to redirect
vehicles while minimizing vehicle vaulting, rolling, and snagging. A comparison of these
barrier shapes is shown in Exhibit 1610-14.

The single-slope barrier face is the recommended option for embedded rigid concrete barrier
applications.

Exhibit 1610-14 Concrete Barrier Shapes

Bridge Transitions: When the single-slope or F-Shape face is used on structures and precast
barrier is selected for use on the approaches; a transition section is needed to provide
gradual stiffening from the less rigid precast barrier system to the more rigid bridge rail
system and to ensure that no vertical edges of the barrier are exposed to oncoming traffic
due to the difference in shapes and height of the barriers. Note: Precast concrete barrier
transitions to bridges are currently under development. Contact HQ Design for more
information. For details on bridge rail designs, see the Bridge Design Manual.

Roadside/Median Shape Transitions: Use a transition section when it is necessary to change

the shape of the barrier within a single run (i.e. Type F to Single Slope, Type 2 to Type F).
Transition designs will differ when used on roadside/wide median applications (subject to
vehicle impacts on one side only), or narrow median applications (subject to vehicle impacts
on both sides). Note: Precast concrete barrier shape transitions for roadside and median
applications are currently under development. Contact HQ Design for more information.

Stiffness Transitions: A transition section is also needed when changing the stiffness of the
barrier system within a single run but not the barrier shape (i.e. Type F anchored to Type F
unanchored). This type of transition requires a change in anchoring pin configuration when
moving from an unanchored barrier system to an anchored barrier system. There is no other
change to the barrier other than the anchoring pin configuration. Note: Precast concrete

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barrier transition plans for barrier system stiffness changes are currently under development.
Contact HQ Design for more information.

For aesthetic reasons, avoid changes in the shape of the barrier face within a project or
corridor.

The New Jersey shape and F-shape barriers are commonly referred to as “safety shapes.” The
New Jersey shape and F-shape have an initial overall height of 32 inches. This height includes
provision for up to a 3-inch future pavement overlay that can reduce the barrier height to 29
inches minimum.

As part of the implementation of MASH-compliant hardware, WSDOT has transitioned from

using New Jersey shape barrier (Type 2 barrier) for precast concrete barrier to using F-shape
concrete barrier (Type F barrier) instead. F-Shape (Type F) barrier is used in permanent or
temporary installations. New Jersey shape (Type 2) barrier is only allowed to be used in
temporary installations. Existing runs of Type 2 barrier permanently installed are allowed to
remain in place. When replacing concrete barrier, use Type F. When removing and resetting
Type 2 barrier, contact HQ Design for more details.
1610.06(1)(a) Safety Shape Barrier

Concrete Barrier Type F (see the Standard Plans) is a freestanding precast barrier that has the
F-shape on both sides. The F-Shape barrier can be used in permanent or temporary
installations. It can be used for both median and shoulder installations. Unanchored units are
connected with steel pins through metal loops. For permanent installations, this barrier is
placed on a paved surface and a paved surface is provided beyond the barrier for deflection.
For temporary installations, this barrier can be placed on a paved or a compacted unpaved
surface with the respective surface provided beyond the barrier for deflection. Do not anchor
Type F barrier on a compacted unpaved surface. See Exhibit 1610-3 for deflection
requirements.

Concrete Barrier Type 2 (see the Standard Plans) is a freestanding precast barrier that has
the New Jersey shape on two sides. The Type 2 barrier is only used in temporary installations.
It can be used for both median and shoulder installations. Unanchored units are connected
with steel pins through wire rope loops. For temporary installations, this barrier can be
placed on a paved surface or a compacted unpaved surface with the respective surface
provided beyond the barrier for deflection. Do not anchor Type 2 barrier on a compacted
unpaved surface. See Exhibit 1610-3 for deflection requirements.

The cost of precast safety shape barrier is significantly less than the cost of the cast-in-place
barriers. Therefore, consider the length of the barrier run and the deflection needs to
determine whether transitioning to precast barrier is desirable. If precast safety shape
barrier is used for the majority of a project, use the single slope barrier for small sections that
need cast-in-place barrier (such as for a light standard section). Precast concrete barrier
transitions are currently under development. Contact HQ Design for more information.

Type F narrow base is a precast, single-faced F-Shape barrier. These units are not
freestanding and are to be placed against a rigid structure (or anchored to the pavement in
temporary installations). If Type F narrow base barriers are used back to back, fill any gap
between them to prevent tipping.

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Type F barrier can be anchored where a more rigid barrier is needed. The barrier can be
anchored in permanent or temporary installations on asphalt pavement, concrete pavement,
or bridge decks (Anchoring methods are shown in the Standard Plans). Consult with the
WSDOT BSO for details when anchoring permanent precast concrete barrier to a rigid
(Portland cement concrete) pavement or bridge deck.

Precast Type 2 barrier can be anchored where a more rigid barrier is needed. The barrier can
be anchored in temporary installations using Type 1 and Type 2 anchors for rigid concrete
pavement, and Type 3 anchors for asphalt pavement (Anchoring methods are shown in the
Standard Plans). Consult with the WSDOT BSO for details when anchoring precast concrete
barrier to a bridge deck.

Precast barrier used on the approach to bridge rail is to be connected to the bridge rail by
installing loops or a loop bar embedded into the bridge rail with epoxy resin and as detailed
in the Standard Plans.

Place unrestrained (unanchored) precast concrete barrier on slopes of 5% (20H:1V) or flatter

where possible. The maximum slope for placement of concrete barrier is 10% (10H:1V).
1610.06(1)(b) Single-Slope Barrier

Single-slope barrier is available in various heights as shown in the Standard Plans. Single-
slope concrete barrier can be cast-in-place or precast. Single-slope barrier is considered a
rigid system regardless of the construction method used provided that precast barrier is
embedded a minimum of 3-inches in the roadway wearing surface (asphalt or concrete) on
both sides, precast barrier is embedded a minimum of 10-inches in compacted soil (i.e. CSBC,
select borrow, gravel borrow, native soil) on both sides, and cast-in-place barrier is
embedded a minimum of 3-inches in the roadway wearing surface (asphalt or concrete) or
compacted soil on both sides.

For new installations in asphalt, concrete, or compacted soil; the minimum height of the
single-slope barrier above the roadway is 2 feet 10 inches which allows a 2-inch tolerance for
future overlays. The minimum total height of the barrier section is 3-feet-6 inches (including
embedment). The single-slope barrier can be installed with grade separation between
roadways as follows:
 For cast-in-place barrier with a minimum 3-inch embedment, or pre-cast barrier
installed in asphalt or concrete with a minimum 3-inch embedment; a grade
separation of up to 4-inches is allowed when using a 3-foot-6-inch tall barrier
section, a grade separation of up to 7-inches is allowed when using a 4-foot tall
barrier section, and a grade separation of up to 10-inches is allowed when using a 4-
foot-6-inch tall barrier section as shown in the Standard Plans.
 For pre-cast barrier installed in compacted soil with a minimum 10-inch
embedment; a grade separation of up to 4-inches is allowed when using a 4-foot tall
barrier section, and a grade separation of up to 10-inches is allowed when using a 4-
foot-6 inch tall barrier section.
 The barrier is to have a depth of embedment equal to or greater than the grade
separation. Contact the WSDOT BSO for grade separations greater than 10-inches.
 Cast-in-place and pre-cast High Performance single-slope barrier can be installed
with a grade separation between the roadways as well, see the Standard Plans.

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Traffic Barriers Chapter 1610

1610.06(1)(c) High-Performance Concrete Barrier

High-Performance Concrete Barrier (HP Barrier) is a rigid barrier with a minimum height of 3-
foot-6-inch above the roadway surface. This barrier is designed to function more effectively
during heavy-vehicle crashes. This taller barrier may also offer the added benefits of reducing
headlight glare and reducing noise in surrounding environments. WSDOT HP Barrier utilizes
the single-slope shape. (See the Standard Plans for barrier details.)

Use HP Barrier in freeway medians of 22 feet or less. Also, use HP Barrier on Interstate or
freeway routes where crash history suggests a need or where roadway geometrics increase
the possibility of larger trucks hitting the barrier at a high angle (for example, on-ramps for
freeway-to-freeway connections with sharp curvature in the alignment).

Consider the use of HP Barrier at other locations such as highways with narrow medians,
near highly sensitive environmental areas, near densely populated areas, over or near mass
transit facilities, or on vertically divided highways.

1610.06(1)(d) Low-Profile Barrier

Low-profile barrier designs are available for median applications where the posted speed is
45 mph or below. These barriers are normally used in urban areas. They are typically 18 to 20
inches high and offer sight distance benefits. For barrier designs, terminals, and further
details, contact the HQ Design Office.

1610.06(2) Concrete Barrier Placement in Front of Bridge Piers

Consult with the HQ Bridge traffic barrier specialist when placing concrete barrier in front of
bridge piers for projects with new or reconstructed bridges. See Standard Plans for barrier
placement in front of bridge piers for retrofit projects.

1610.06(3) Concrete Barrier Height

Overlays in front of safety shape concrete barriers can extend to the top of the lower, near-
vertical face of the barrier before adjustment is necessary.
 Allow no less than 2-foot 5 inches from the pavement to the top of the safety shape
barriers. Allow no less than 2-foot 8-inches from the pavement to the top of the
single-slope barrier.

1610.06(4) Concrete Barrier Terminals

Whenever possible, bury the blunt end of a concrete barrier run into the backslope of the
roadway. If the end of a concrete barrier run cannot be buried in a backslope or terminated
as described below, terminate the barrier using a guardrail terminal and transition or an
impact attenuator (see Chapter 1620).

To bury the blunt end of the barrier into a backslope, the following conditions must be met:
 The backslope is 3H:1V or steeper
 The backslope extends minimum of 4 feet in height above the edge of shoulder

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Chapter 1610 Traffic Barriers

 Flare the concrete barrier into the backslope using a flare rate that meets the
criteria in Section 1610.03(4)
 Provide a 10H:1V or flatter foreslope into the face of the barrier and maintain the
full barrier height until the barrier intersects with the backslope. This might create
the need to fill ditches and install culverts in front of the barrier face.

The 10- to 12-foot single-slope barrier terminal (precast or cast-in-place) may be used in the
following conditions:
 Outside the Design Clear Zone.
 On the trailing end of the barrier when it is outside the Design Clear Zone for
opposing traffic.
 On the trailing end of one-way traffic.
 Where the posted speed is 25 mph or below.

See the Standard Plans for barrier terminal details. Note: The Type F concrete barrier
terminal standard plans are currently under development. Contact HQ Design for
information.

1610.07 Bridge Traffic Barriers

Bridge traffic barriers redirect errant vehicles and help to keep them from going over the side
of the structure. (See the Bridge Design Manual for information regarding bridge barrier on
new bridges and replacement bridge barrier on existing bridges).

When considering work on a bridge traffic barrier consult the WSDOT Bridge and Structures
Office (BSO).

The standard bridge traffic barrier is a 3 foot 6 inch single slope or F Shape traffic barrier.

For corridor continuity, a 2 foot 10 inch single slope or 2 foot 8 inch F Shape traffic barrier
may be used with a pedestrian railing attached to the top for a total height of 3 foot 6 inch
height inches. This also meets requirements for worker fall protection.

Approach barriers, transitions, and connections are usually needed on all four corners of
bridges carrying two-way traffic and on both corners of the approach end for one-way traffic.
(See 1610.04(6) for guidance on beam guardrail transitions). A concrete barrier transition is
being made available to connect the Type F concrete barrier (F-shape) and the bridge barrier
(F-Shape or Single Slope) (Note: Transitions are currently under development. Contact HQ
Design for further details).

Bridge railing attaches to the top of the bridge barrier. When bridge barrier is included in a
project, the bridge rails, including crossroad bridge rail, are to be addressed. Consult the
WSDOT BSO regarding bridge rail selection and for design of the connection to an existing
bridge. Consider the following:
 Use an approved, NCHRP 350 or MASH crash-tested bridge traffic barrier on new
bridges or bridges to be widened. The Bridge Design Manual provides examples of
typical bridge rails. The BSO’s minimum crash test level for all state and interstate
bridges is a TL-4.

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Traffic Barriers Chapter 1610

 An existing bridge rail on a roadway with a posted speed of 30 mph or below may
remain in place if it is not located on a bridge over a National Highway System (NHS)
highway. When Type 7 bridge rail is present on a bridge over an NHS highway with a
posted speed of 30 mph or below, it may remain in place regardless of the type of
metal rail installed. Other bridge rails are to be evaluated for strength and
geometrics. (See 1610.07(1) for guidance on retrofit techniques.)
 The Type 7 bridge rail is common. Type 7 bridge rails have a curb, a vertical-face
parapet, and an aluminum top rail. The curb width and the type of aluminum top
rail are factors in determining the adequacy of the Type 7 bridge rail, as shown in
Exhibit 1610-15. Consult the WSDOT BSO for assistance in evaluating other bridge
rails.
 When considering an overlay on a bridge, consult the WSDOT BSO to verify the
overlay depth can be placed on the bridge deck based on the type of traffic barrier.
There may be instances where the height of the bridge barrier will not allow for the
planned overlay depth without removal of existing pavement.

Exhibit 1610-15 Type 7 Bridge Rail Upgrade Criteria

Curb Width
Aluminum Rail
Type
9 Inches or Less Greater Than 9 Inches*

Type R, S, Bridge rail

Bridge rail adequate
or SB adequate

Bridge rail Upgrade

Type 1B or 1A
adequate bridge rail

Other Consult the WSDOT BSO

*When the curb width is greater than 9 inches, the

aluminum rail must be able to withstand a 5 kip load.

1610.07(1) Bridge Barrier Retrofit

If the bridge barrier system does not meet the criteria for strength and geometrics,
modifications to improve its redirectional characteristics and its strength may be needed.
Consult the WSDOT BSO to determine which retrofit method described below can be
completed.

1610.07(1)(a) Concrete Safety Shape

Consult the WSDOT BSO to determine whether the existing bridge deck and other
superstructure elements are of sufficient strength to accommodate this bridge barrier

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Chapter 1610 Traffic Barriers

system and provide design details for the retrofit. Retrofitting with a new concrete bridge
barrier is costly and requires authorization from Program Management when no widening is
proposed.
1610.07(1)(b) Thrie Beam Retrofit
Retrofitting the bridge barrier with thrie beam is an economical way to improve the strength
and redirectional performance of a bridge barrier. The thrie beam can be mounted to steel
posts or the existing bridge barrier, depending on the structural adequacy of the bridge deck,
the existing bridge barrier type, the width of curb (if any), and the curb-to-curb roadway
width carried across the structure. Exhibit 1610-16 shows typical retrofit criteria.

Note that Bridges designated as historical landmarks may not be candidates for thrie beam
retrofitting. Contact the Environmental Services Office regarding bridge historical landmark
status.

Consider the Service Level 1 (SL-1) system on bridges with wooden decks and for bridges with
concrete decks that do not have the needed strength to accommodate the thrie beam
system. Contact the WSDOT BSO for information needed for the design of the SL-1 system.

If a thrie beam retrofit results in reduction in sidewalk width ensure ADA compliance is
addressed, see Chapter 1510.

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Traffic Barriers Chapter 1610

Exhibit 1610-16 Thrie Beam Rail Retrofit Criteria

Concrete Bridge Deck

Curb Bridge Wood Bridge Deck or
Low- Strength
Width Width Steel or Wood Post
Concrete Bridge Rail (existing) Concrete Deck
Bridge Rail (existing)

Thrie beam mounted to existing  Service Level 1

Thrie beam mounted to
[2]
bridge rail and blocked out Bridge Rail. [2]
<18 inches steel posts [2] at the face
of curb. Height = 32 inches  Height = 32
to the face of curb. Height = 32
inches. inches.
[2]
Thrie beam mounted to steel posts at the face of curb. [1]  Curb or wheel
> 28 ft
>18 inches guard needs to
(curb to curb) Height = 32 inches.
be removed.
Thrie beam mounted to
Thrie beam mounted to existing
< 28 ft steel posts [2] in line with
>18 inches bridge rail.[2]
(curb to curb) existing rail.
Height = 35 inches.
Height = 35 inches.

Notes:
[1] To maximize available curb/sidewalk width for pedestrian use, thrie beam may
be mounted to the bridge rail at a height of 35 inches.
[2] Contact the WSDOT BSO for design details on bridge rail retrofit projects.

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Chapter 1610 Traffic Barriers

1610.08 Other Barriers

1610.08(1) Redirectional Landform

Redirectional landforms, also referred to as earth berms, were formerly installed to help
mitigate crashes with fixed objects located in depressed medians and at roadsides. They
were constructed of materials that provided support for a traversing vehicle. With slopes in
the range of 2H:1V to 3H:1V, they were intended to redirect errant vehicles. The use of
redirectional landforms has been discontinued. Where redirectional landforms currently
exist as mitigation for a fixed object, provide alternative means of mitigating the fixed object,
such as removing, relocating, changing the fixed object to a crash-tested breakaway system,
or shielding with barrier.

1610.08(2) Aesthetic Barrier Treatment

An aesthetic barrier may be desired on a project, or it may be required by a memorandum of
understanding, a Scenic Byway designation, an easement or corridor management plan, or as
a result of stakeholder engagement. Contact the region or HQ Landscape Architect Office to
confirm this requirement, and to verify any specific conditions with respect to the barrier’s
appearance in the applicable plan or corridor document. Reactive coloring agents and
powder coating are approved treatment options for w-beam guardrail, and may be
applicable to other barrier types. Check with the manufacturer and/or the product
documentation when specifying aesthetic treatment for proprietary devices, such as
guardrail terminals.

One alternative to the use of aesthetic treatments are barriers designed to be aesthetic, such
as steel-backed timber guardrail and stone guard walls. These alternative barriers will likely
necessitate a partnering effort because of their higher costs, although grants may be
available for this purpose if the need is identified early in the project definition phase.

1610.08(3) Steel-Backed Timber Guardrail

Steel-backed timber guardrails consist of a timber rail with a steel plate attached to the back
to increase its tensile strength. There are several variations of this system that have passed
crash tests. The nonproprietary systems use a beam with a rectangular cross section that is
supported by either wood or steel posts.

A proprietary (patented) system, called the Ironwood Guardrail, is also available. This system
uses a beam with a round cross section and is supported by steel posts with a wood covering
to give the appearance of an all-wood system from the roadway. The incorporation of the
Ironwood Guardrail will need to be documented. Consult with the Assistant State Design
Engineer to determine what justification (proprietary or a public interest finding) will be
required.

The most desirable method of terminating the steel-backed timber guardrail is to bury the
end in a backslope, as described in 1610.04(5). When this type of terminal is not possible, use
of the barrier is limited to highways with a posted speed of 45 mph or below. On these

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Traffic Barriers Chapter 1610

lower-speed highways, the barriers can be flared away from the traveled way as described in
1610.03(4) and terminated in a berm outside the Design Clear Zone.

For details on these systems, contact the HQ Design Office.

1610.08(4) Stone Guardwalls

Stone guardwalls function like rigid concrete barriers but have the appearance of natural
stone. These walls can be constructed of stone masonry over a reinforced concrete core wall
or of simulated stone concrete. These types of barriers are designed to have a limited
textured projection of the stones to help aid in the redirectional characteristics of the barrier.
The most desirable method of terminating this barrier is to bury the end in a backslope, as
described in 1610.06(3). When this type of terminal is not possible, use of the barrier is
limited to highways with a posted speed of 45 mph or below. On these lower-speed
highways, the barrier can be flared away from the traveled way and terminated in a berm
outside the Design Clear Zone.

For details on these systems, contact the HQ Design Office.

1610.08(5) Dragnet
The Dragnet Vehicle Arresting Barrier consists of chain link or fiber net that is attached to
energy absorbing units. When a vehicle hits the system, the Dragnet brings the vehicle to a
controlled stop with limited damage. Possible uses for this device include the following:
 Reversible lane entrances and exits
 Railroad crossings
 Truck escape ramps (instead of arrester beds—see Chapter 1270)
 T-intersections
 Work zones
 Swing span bridges

Coordinate with the HQ Design Office for design details.

1610.09 References

1610.09(1) Design Guidance

WSDOT Roadside Safety site:
 http://www.wsdot.wa.gov/Design/Policy/RoadsideSafety.htm

Bridge Design Manual LRFD, M 23-50, WSDOT

Roadside Design Guide, AASHTO, 2011 with Errata (July 2015)

Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans), M 21-01,
WSDOT

Traffic Manual, M 51-02, WSDOT

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Chapter 1610 Traffic Barriers

1610.09(2) Supporting Information

Manual for Assessing Safety Hardware (MASH), AASHTO, 2016

Manual for Assessing Safety Hardware (MASH), AASHTO, 2009

NCHRP 350, TRB, 1993

Determining Length of Need. This e-learning course for WSDOT employees covers the
“Length of Need,” which is a calculation of how much longitudinal barrier is necessary to
shield objects on the roadside. Request this training via the web-based Learning
Management System.

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Chapter 1620 Impact Attenuator Systems
1620.01 General
1620.02 Design Criteria
1620.03 Selection Considerations
1620.04 Transportable Attenuators (Truck-Mounted and Trailer-Mounted)
1620.05 Older Systems
1620.06 Inertial Barrier Systems (Sand Barrels)

1620.01 General
Impact attenuator systems are protective systems that help aid an errant vehicle from impacting
an object by either gradually decelerating the vehicle to a stop when hit head-on or by
redirecting it away from the feature when struck on the side. These systems are used for rigid
objects or other features that cannot be removed, relocated, or made breakaway.

Approved systems shall meet standardized testing defined in the American Association of State
Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH)
as updated in 2016. In addition, these devices shall have an acceptance letter from FHWA that
certifies that the device meets the appropriate crash test criteria and is eligible for federal-aid
reimbursement.

1620.02 Design Criteria

The following design criteria apply to new, existing, or reset permanent and temporary impact
attenuators.

Impact attenuators are placed so that they do not present a feature that requires mitigating in
relation to opposing traffic. For median and reversible lane locations, the backup structure or
attenuator-to-object connection is designed to help in aiding opposing traffic from being
snagged.

Avoid placement of curbs between attenuators and traffic. Refer to the specific attenuator
manufacturer’s instructions if considering placement of curbing between an attenuator and the
travelled way. It is desirable that existing curbing be removed and the surface smoothed with
asphalt or cement concrete pavement before an impact attenuator is installed. However,
mountable curbs 4 inches or less in height may be retained depending on the feasibility of
removal and as long as the manufacturer’s installation requirements are met.

In general, attenuators are aligned parallel to the roadway.

Consult with the Area Maintenance Superintendent who will be maintaining the system prior to
selecting the attenuator systems to include in a construction contract.

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1620.03 Selection Considerations

WSDOT classifies impact attenuators as permanent (for final installations that will remain in
place) or temporary (for systems that will be in place during work zone traffic control operations
and then removed). Some impact attenuator systems can be used in both a temporary capacity
and then in a final/permanent installation.

For approved systems to choose from, see the WSDOT Impact Attenuator Design page at
http://www.wsdot.wa.gov/publications/fulltext/design/ProductFolder/PENDING_Impact_Att
enuator_Design.docx.
Consider that each application is unique when selecting impact attenuators for use in particular
applications. This applies to both permanent and temporary installations.

To select an appropriate impact attenuator system, the following factors must be assessed:
• Posted speed
• Operating speed
• Average daily traffic (ADT)
• Repair crew exposure
• Proximity to the roadway
• Anticipated number of yearly impacts
• Available space (length and width)
• Lifecycle Maintenance costs
• Initial cost
• Duration (permanent or temporary use)
• Portion of the impact attenuator that is redirective/gating (see Exhibit 1620-1)
• Width of object to be shielded

Entries on the WSDOT Impact Attenuator Design page indicate whether the system is National
Cooperative Highway Research Program (NCHRP) Report 350 or MASH-compliant. If it’s
determined that a MASH-compliant system is not available for the specific configuration
required, document the selection of an NCHRP 350 system in the DDP.

When selecting the appropriate impact attenuator system, consider the portion that is designed
to redirect vehicles during a side impact of the unit, such that fixed objects, either permanent or
temporary (such as construction equipment), are not located behind the gating portion of these
devices (see Exhibit 1620-1).

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Chapter 1620 Impact Attenuator Systems

Exhibit 1620-1 Impact Attenuator Distance Beyond Length of Need

Notes:

[1] Impact attenuator type and manufacturer varies with application. See the Attenuator Selection
Template at:
http://www.wsdot.wa.gov/publications/fulltext/design/ProductFolder/Impact_attenuator_selectio
n_template.xlsx)
[2] Distance beyond the length of need. This portion is gating.
[3] This portion is redirective (nongating) and can be included as part of the barrier needed to satisfy
length of need.
[4] Concrete barrier shown for illustration purposes only. Type of fixed object varies.

Select the system and configuration appropriate for the posted speed. In the interest of a cost-
effective design, selecting a system applicable for the posted speed is recommended (although
using a system tested for a higher speed is acceptable). Note that attenuators used on highways
with posted speeds of 70 mph have additional considerations discussed below. Where there is
evidence that the average operating speed of the facility is higher than the posted speed,
consider selecting an attenuator system rated at the facility’s operating speed.

Manufacturer’s product information may indicate that a different system is required for speeds
of 70 mph or greater. These models are generally referred to as “high speed” or “70 mph”
systems. Use of these systems on facilities with 70 mph posted speeds is not required, and
selection of a system rated for at least 60 mph will typically be appropriate for most sites on
these facilities. For permanent installations where unusual conditions warrant consideration of a
high-speed device, these systems are available and may be used with justification. Contact the
HQ Design Office for guidance when considering one of these systems.

For information regarding spatial requirements and initial cost information related to impact
attenuator systems, see the Attenuator Selection Template at:
http://www.wsdot.wa.gov/publications/fulltext/design/ProductFolder/Impact_attenuator_sel
ection_template.xlsx.

When considering maintenance costs, anticipate the average annual impact rate. If few impacts
are anticipated, lower-cost devices might meet the need. (See Chapter 301 for examples of how
to determine lifecycle costs for proposed hardware). Attenuators with the lowest initial cost and
initial site preparation will have high maintenance costs after each impact. Labor and equipment

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Impact Attenuator Systems Chapter 1620

are needed to clean up the debris and install a new attenuator, as the lowest cost attenuators
are typically destroyed after a single impact. Attenuators with higher initial installation cost
typically have lower maintenance costs.

In selecting a system, one consideration is the anticipated exposure to traffic that the workers
making the repairs may encounter. In areas with high traffic exposure, a low-maintenance
system that can be repaired quickly is most desirable. Some systems need nearly total
replacement or replacement of critical components (such as cartridges or braking mechanisms)
after a head-on impact, while others simply need to be reset.

When a transition to connect with a concrete barrier, fixed object, or beam guardrail is needed,
the transition type and connection may need to be specified (see the impact attenuator
descriptions accessible through the Attenuator Selection Template at:
http://www.wsdot.wa.gov/publications/fulltext/design/ProductFolder/Impact_attenuator_sel
ection_template.xlsx).

In most cases, the transition type and connection required will be a custom design per the
manufacturer (these transitions are included in the cost of the impact attenuator). In a few
cases, the transition type and connection to use will be as described in Chapter 1610 and the
Standard Plans (these transition sections are not included in the cost of the impact attenuator
and must be included as a separate bid item in the construction contract).

Consult with the Area Maintenance Superintendent who will be maintaining the systems before
finalizing the list of attenuators to be included in the contract.

1620.03(1) Low-Maintenance Category

Low maintenance devices have a higher initial cost, requiring substantial site preparation,
including a backup or anchor wall in some cases, and cable anchorage at the front of the
installation. However, repair costs are very low, with labor typically being the main expense.
Maintenance might not be needed after minor side impacts with these systems.

Installation of a low-maintenance device is desirable at locations that meet at least one of the
following criteria:
• Sites with an ADT of 25,000 or greater
• Sites with a history/anticipation of more than one impact per year
• Sites with unusually challenging conditions, such as limitations on repair time, a
likelihood of frequent night repairs, or narrow gore locations
Document the decision in the DDP to use any device other than a low-maintenance device at
locations meeting at least one of the criteria above.

The HQ Design Office conducts a periodic review of maintenance records to consider which
devices should be included in the Low-Maintenance category. For a description of requirements
that need to be met in order to be included in the Low-Maintenance category, see:
 www.wsdot.wa.gov/publications/fulltext/design/roadsidesafety/low_maint.pdf

1620.03(2) Documenting Attenuator Selection

As the factors discussed previously are analyzed, identify inappropriate systems and eliminate
them from further consideration. List the systems that are not eliminated in the contract. When
the site conditions vary, it might be necessary to have more than one list of acceptable systems

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Chapter 1620 Impact Attenuator Systems

within a contract. Acceptable systems cannot be eliminated without documented justification as

to why they should not be used. Also, wording such as “or equivalent” is not to be used when
specifying these systems. If it’s determined that MASH-compliant system in not available for a
specific configuration, NCHRP 350 systems may be used, with Assistant State Design Engineer
approval.
Document attenuator selection using the Attenuator Selection Template found at:
http://www.wsdot.wa.gov/publications/fulltext/design/ProductFolder/Impact_attenuator_sel
ection_template.xlsx

1620.04 Transportable Attenuators (Truck-Mounted and Trailer-Mounted)

Truck Mounted Attenuators and Trailer-Mounted Attenuators are portable systems mounted
on trucks or trailers. They are intended for use in work zones and for temporary applications.

1620.05 Older Systems

Many older systems are in use on Washington State highways and may be left in place or reset
with concurrence of the WSDOT Area Maintenance Superintendent who maintains the system.
New installations of these systems are not allowed.

For a list of older systems see:

http://www.wsdot.wa.gov/publications/fulltext/design/ProductFolder/PENDING_Impact_Att
enuator_Design.docx.

1620.06 Inertial Barrier Systems (Sand Barrels)

Inertial barrel systems (sand barrels) commonly provide advantages in temporary installations
where the locations change and there is sufficient space available or in permanent locations
where there is a lower risk of collisions and where the debris, from the initial barrier when hit,
will have a minimal impact to traffic. Refer to the manufacturer for system dimensions and
specifications.

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Impact Attenuator Systems Chapter 1620

Page 1620-6 WSDOT Design Manual M 22-01.16

February 2019
Chapter 1710 Safety Rest Areas
1710.01 General
1710.02 References
1710.03 Definitions
1710.04 Safety Rest Area Project Team
1710.05 Location, Access, and Site Design
1710.06 Buildings
1710.07 Utilities
1710.08 Documentation

1710.01 General
The Washington State Department of Transportation (WSDOT) has developed a
statewide system of traveler stopping opportunities along Interstate highways and
state routes. This system includes safety rest areas (see Exhibit 1710-1), roadside
parks, and viewpoints. These services provide universal access for rest, traveler
information, and restroom facilities. Benefits include improved safety by reducing
driver fatigue and the number of vehicles parked on the shoulders of state routes,
refuge from adverse driving conditions, and increased tourism promotion.
Safety rest areas (SRAs) are spaced approximately every 60 miles on the National
Highway System and on Scenic and Recreational Highways. Use the Safety Rest Area
Program Strategic Plan as a guide when selecting a site location. The link to the SRA
Strategic Plan can be found in the SRA Section of the Capital Facilities Office internal
web page at:  http://wwwi.wsdot.wa.gov/operations/facilities/
Safety rest areas are planned and designed by a multidisciplinary team lead through
the Facilities Administrator in the Capital Facilities Office, a branch of Maintenance
Operations. (See 1710.04 for an expanded discussion on team roles and membership.)

Photo: Keith Anderson, VERG

WSDOT Safety Rest Area

Exhibit 1710-1

WSDOT Design Manual M 22-01.09 Page 1710-1

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Safety Rest Areas Chapter 1710

1710.02 References
(1) Federal/State Laws and Codes
23 Code of Federal Regulations (CFR) 1.23, Rights-of-way
23 CFR 635, Construction and Maintenance
23 CFR 752, Landscape and roadside development
23 CFR 771, Environmental impact and related procedures
42 United States Code (USC) Chapter 126, Section 12101 et seq., Americans with
Disabilities Act of 1990
20 USC Chapter 6A, Section 107, The Randolph-Sheppard Act
Revised Code of Washington (RCW) 46.17.375, Recreational vehicle sanitary disposal fee
RCW 46.68.170, RV account – Use for sanitary disposal systems
RCW 47.01.460, Adjustments to recreational vehicle fees
RCW 47.06.040, Statewide multimodal transportation plan
RCW 47.28.030, Contracts – State forces
RCW 47.38, Roadside areas – Safety rest areas
RCW 47.39, Scenic and Recreational Highway Act of 1967
RCW 47.42, Scenic Vistas Act
Washington Administrative Code (WAC) 246-290, Group A public water supplies
WAC 468-66, Highway Advertising Control Act

(2) Design Guidance

As the lead WSDOT organization for SRA project teams, the Capital Facilities Office
coordinates design details and standards for SRA-related items.
ADA Accessibility Guidelines for Buildings and Facilities (ADAAG)
 www.access-board.gov/adaag/html/adaag.htm
Manual on Uniform Traffic Control Devices for Streets and Highways, USDOT, FHWA;
as adopted and modified by Chapter 468-95 WAC “Manual on uniform traffic control
devices for streets and highways” (MUTCD)
 www.wsdot.wa.gov/publications/manuals/mutcd.htm
Highway Runoff Manual, M 31-16, WSDOT
Hydraulics Manual, M 23-03, WSDOT
Plans Preparation Manual, M 22-31, WSDOT
Maintenance Manual, M 51-01, WSDOT
Right of Way Manual, M 26-01, WSDOT
Roadside Manual, M 25-30, WSDOT
Roadside Policy Manual, M3110, WSDOT

Page 1710-2 WSDOT Design Manual M 22-01.13

July 2016
 Standard Plans for Road, Bridge, and Municipal Construction (Standard Plans),
M 22-01, WSDOT
Traffic Manual, M 51-02, WSDOT

(3) Supporting Information

Safety Rest Area Strategic Plan, WSDOT Capital Facilities Office
 http://wwwi.wsdot.wa.gov/operations/facilities/
Guide for Development of Rest Areas on Major Arterials and Freeways, AASHTO
Task Force on Geometric Design
Project Management Online Guide, WSDOT

(4) Agreements
Interpretive Signs and Markers Agreement – Washington State Parks Commission
 (GM 869) 1989 Highways and Local Programs Division
Traveler and Commercial Information Services – Private Vendor (StoreyCo, Inc.)
 (AA-1-12097) 2007 Capital Facilities Office
Vending Machines – Department of Services for the Blind (DSB)
 (GCA 10377) Capital Facilities Office

1710.03 Definitions
ancillary services Those secondary services, also considered amenities, provided
at safety rest areas that include, but are not limited to, vending machines, picnic areas,
interpretive signing, telephones, recreational vehicle (RV) sanitary disposal facilities,
trails, scenic viewpoints, commercial and public information displays, and visitor
information centers.
Recreational Vehicle Account In 1980 the RV account was established for use by
the department of transportation for the construction, maintenance, and operation of
recreational vehicle sanitary disposal systems at safety rest areas (RCW 46.68.170).
A recreational vehicle sanitary disposal fee is required for registration of a recreational
vehicle (RCW 46.17.375). Adjustments to the recreational vehicle fee by the department
of transportation may be implemented after consultation with the citizens’ representatives
of the recreational vehicle user community (RCW 47.01.460).
roadside park A roadside user facility for safe vehicular parking off the traveled way
and separated from the highway by some form of buffer. These sites might be equipped
with features or elements such as points of interest, picnic tables, and/or vault toilet
buildings. Unlike a safety rest area, a roadside park does not always provide a permanent
restroom building.

safety rest area (SRA) A roadside facility equipped with permanent restroom
building(s), a parking area, picnic tables, refuse receptacles, illumination, and other
ancillary services. SRAs typically include potable water and might include traveler
information and telephones.

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Safety Rest Areas Chapter 1710

Safety Rest Area Strategic Plan Developed in 2008 under a stakeholder-coordinated

effort of executive and advisory team members, this plan provides guidance for current
and future management of the SRA program.
traveler information Commercial and noncommercial information that informs and
orients the traveling public. This includes access information for food, gas, lodging, local
attractions, regional tourist attractions, roadway conditions, and construction schedules.
universal access Access for all persons regardless of ability or stature.
viewpoint A roadside stopping opportunity with a view of some point of interest or
area scenery. This area is not typically separated from the traveled way by some form
of highway buffer.
Visitor Information Center (VIC) A staffed or nonstaffed booth or separate building
that displays and dispenses free tourist travel maps and brochures. These are typically
located at border-entry SRAs to provide travel information to highway users as they
enter the state.

1710.04 Safety Rest Area Project Team

The Capital Facilities Office has primary responsibility for program oversight and
communication and is the primary point of contact for questions concerning SRAs.
Duties include planning and programming for capital Preservation and Improvement
projects, maintenance operations oversight and policy development, and project delivery.

Exhibits 1710-2 and 1710-3 outline the many disciplines involved with SRA planning,
design, construction, and maintenance. The exhibits outline roles during the different
phases of SRA management. Services are provided by internal WSDOT staff, other
government agencies, and private consultants.

1710.05 Location, Access, and Site Design

(1) Conformance With the Safety Rest Area Strategic Plan
Regional planners, in coordination with the Capital Facilities Office, will use the Safety
Rest Area Strategic Plan as a guide to determine which areas in the state are potential
areas of need for a new facility. Verify current locations of SRAs, roadside parks,
viewpoints, and undeveloped SRA properties that could be utilized for development
of a new SRA. Coordinate all SRA planning and design efforts with the SRA Program
located in the Capital Facilities Office.

(2) Highway Spacing Guidelines

It is preferred to space SRAs and roadside parks approximately every 60 miles on the
National Highway System and Scenic Byways. Consider the location of other available
public facilities when deciding where to locate an SRA. Other public or private facilities
may offer stopping opportunities that could mitigate the need for construction of a new
SRA. Reference the SRA Strategic Plan for potential areas of need for new stopping
opportunities.

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Chapter 1710 Safety Rest Areas

Programming & Operations & Agreements &

WSDOT Office Planning Design Construction
Budget Maintenance[1] Partnerships
Capital Facilities Lead Lead Lead Lead Oversight Lead
Maintenance
Support N/A Support Support Lead Lead/Support
Operations
Capital Program
Approver Approver Approver Approver N/A N/A
Development
Budget and
N/A Approver N/A N/A N/A N/A
Financial Analysis
Highways and
Support N/A Support N/A N/A Support
Local Programs
Design Support N/A Support Support N/A N/A
Construction NA N/A Support Support N/A N/A
Landscape Support N/A Support Support Support N/A
Architect
Utilities NA N/A Support Support Support Support
Environmental Support N/A Support Support Support N/A
Hydraulics Support N/A Support Support N/A N/A
Traffic Support N/A Support Support Support N/A
Public-Private
Support N/A Support N/A N/A Lead/Support
Partnerships
Freight Systems
Support N/A Support N/A N/A Support
Division
Statewide Travel
and Collision Support N/A Support N/A N/A N/A
Data
Real Estate
Support N/A Support N/A Support Support
Services
Emergency
Support N/A Support N/A Support N/A
Management

Note:
[1] The SRA section in the WSDOT Maintenance Manual provides additional information pertaining to daily
operations at the rest areas. Operations policy is outlined for all the ancillary services provided at each
rest area site, such as the free coffee program, vending machines, literature distribution and posting,
site security, seasonal or temporary closures, and other site activities.

WSDOT’s SRA Project and Programming Roles

Exhibit 1710-2

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July 2012
Safety Rest Areas Chapter 1710

Programming & Operations & Agreements &

Organization Planning Design Construction
Budget Maintenance Partnerships
Federal Highways
Approver N/A Approver Approver Support Approver
Administration
Attorney General N/A N/A N/A N/A N/A Support
Washington State
Support N/A Support Support Support Support
Patrol
Department of
Support N/A N/A N/A N/A Support
Commerce
Washington State
Support N/A Support N/A N/A Support
Historical Society
RV Citizens Advisory
Support Support Support N/A Support Support
Committee[1]
Association of
Visitor Information Support N/A N/A N/A N/A Support
Centers of WA
Washington State
Hotel and Lodging Support N/A N/A N/A N/A Support
Association

Note:
[1] Recreational Vehicle Citizens Advisory Committee: The department utilizes a volunteer citizen-based
group of recreational vehicle users to help define the RV needs at SRAs. This group provides guidance
on the expenditure of funds from the RV account and fee adjustments. The fee adjustments must be
preceded by an evaluation per RCW 47.01.460.

Additional Safety Rest Area Resources

Exhibit 1710-3

(3) Adjacent Land Use

Consult local planning offices for information about zoning and expected development
in the area of a proposed site to ensure compatibility with a new safety rest area or
roadside park. Acquire a buffer area or scenic easement on adjacent lands, if possible,
to protect scenic views and existing vegetation. Incorporate any cultural, historical,
or scenic points of interest into the site design to enhance visitor experience and area
education. For Interstate safety rest areas, vehicular ingress and egress will be from
the main line only.

(4) Availability of Utilities

Determine the proximity and availability of water, power, and sewer systems prior to
site acquisition. Prepare required legal documents such as well agreements, easements,
water rights, and acquisition documents. The Capital Facilities Office uses annual traffic
data in the area to estimate the number of rest area users and determine the adequacy of
potable water supply, power capacity, parking space needs, and sewage disposal system
options. New construction should meet the 20-year projected growth rate based on
potential traffic increases.

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Chapter 1710 Safety Rest Areas

(5) Level of Development

Roadside facilities have different levels of development and require varying site size and
amenity levels. Exhibit 1710-4 shows recommended site sizing and amenities for SRAs,
roadside parks, and viewpoints.

(6) Site Conditions

SRAs need large parcels of land to provide adequate space for parking passenger vehicles
and trucks, on-site sewage treatment, and on-site water systems if provided. Any selected
site should consider the terrain to allow for safe ingress and egress from the highway.
Other considerations are:
 Grades and slopes to accommodate parking, sewage treatment, and the building site.
 High water level, particularly if the site is in a floodplain.
 Soil conditions and soil type for structural designs and the on-site sewage treatment
system.
 Vegetation and natural features to understand potential mitigation costs from
impacts to existing wetlands or stormwater drainage, etc.
 Prevailing wind direction and typical wind velocities that can affect building
siting/design and visitor experience.

(7) Site Security

Design the facility to maximize line of sight for rest area users. Design vegetation for
visibility to avoid hiding places on-site. If electrical power is available on-site, provide
lighting around all parking areas, buildings, and other site amenities that are made
available to the public.

(8) Site Sustainability

During site development, adhere to the U.S. Green Building Council’s Leadership
in Energy and Environmental Design standards where practicable. Strive for energy
efficiency, water conservation, and low operational costs in building designs. Ensure
landscaping features will be durable and easy to maintain. Contact the Capital Facilities
Office for minimum requirements and standard details.

(9) Stormwater Management

For stormwater management, particularly in areas covered by the National Pollutant
Discharge Elimination System (NPDES) permit, make an effort to minimize the use
of storm drainage devices such as catch basins, oil-water separators, and retention
vaults. Design the site to accommodate sheet flow off paved surfaces to vegetative
areas for on-site infiltration and management of stormwater where practicable. (See
the Highway Runoff Manual for stormwater design information.)

(10) Traffic Ingress and Egress

Design connections to the main line highway in accordance with Design Manual chapters
in Division 13. Consult with the HQ Access and Hearings Section for establishing new
or modifying existing highway access points.

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Safety Rest Areas Chapter 1710

Site Development Safety Rest Area Roadside Park Viewpoint

Site
Minimum site size – Professional judgment should
Up to 30 acres Up to 3 acres Up to 1 acre
be used based on site-specific requirements
ADAAG code compliance Required Required Required
Utilities
Potable water Optional Optional No
Off-site sewage disposal Optional Optional No
On-site sewage disposal Optional Optional No
RV sanitary disposal systems Optional No No
Electrical power Optional Optional Optional
Electric vehicle charging stations* Optional No No
Restroom Buildings
Permanent building Required Optional No
Toilets and hand cleaning Required Optional No
Portable toilets: vault, chemical, or composting Optional Optional Optional
ADAAG code compliance Required Required Required
Parking and Pavement
Impervious Required Optional Optional
Truck parking Optional Optional No
RV parking Optional Optional Optional
Site Amenities
Pedestrian plaza Optional Optional No
Sidewalks Optional Optional Optional
Picnic tables Optional Optional Optional
Recreation trails Optional Optional Optional
Pet walking area Optional Optional No
Bicycle access and/or racks Optional Optional Optional
Historical or area information display Required Optional Optional
Ancillary Services
Telephone service Optional Optional No
Refuse receptacles Required Optional Optional
Vending machines* Optional No No
Volunteer refreshment area* Optional No No
Visitor information booth* Optional No No
Travel information kiosk* Optional Optional No
Interpretive displays, markers, or memorial signs Optional Optional Optional
Safety and Security
Fencing Optional Optional Optional
Site illumination* Optional Optional No
Surveillance cameras* Optional No No
*If provided, electrical power is required.

Roadside Facilities Level of Development

Exhibit 1710-4

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Chapter 1710 Safety Rest Areas

(11) ADAAG Compliance

You must comply with the Americans with Disabilities Act Accessibility Guidelines
(ADAAG) for all site components that are made available to the public. Provide at least
one accessible route of travel, defined in ADAAG, from the parking area to each on-site
amenity or ancillary service.

(12) Parking Area Design

Consider the parking area layout when generating a site master plan. Include stages
of construction if applicable. Provide separate parking areas for trucks/RVs/buses
and passenger cars. For new designs, locate large-vehicle parking on the far side
of the site away from the highway for improved highway visibility and site security
purposes. Provide shade for vehicles where practicable. Exhibit 1710-5 shows an
example of a truck parking area layout. AASHTO’s Guide for Development of Rest
Areas on Major Arterials and Freeways provides parking area design considerations.
Consider areas for snow storage needs. Refer to the Hydraulics Manual for drainage
design. Preserve existing landscape features to the greatest extent possible. Design
vehicular and pedestrian routes to be safe, simple, direct, and obvious. Meet local
building codes and ADAAG requirements for public parking.

(13) Recreational Vehicle (RV) Sanitary Disposal Facilities

Construct RV sanitary disposal facilities (dump stations) only at sites served by
municipal sewage disposal systems, or at sites served by sewage lagoons with adequate
capacity. On-site septic systems with drainfields are not an option for RV dump stations
because of sewage volume, technical/maintenance requirements, and costs. Contact the
Capital Facilities Office for details on RV dump station design and operation.

(14) Walkways
Design walkways for direct pedestrian movement to all facilities and comply with
ADAAG requirements. Provide sidewalk width a minimum of 48 inches, which
exceeds ADAAG requirements.

(15) Vegetation
Vegetation enhances the physical environment by providing shade, shelter from wind,
visual screening, wildlife habitat, and other benefits. Landscape Architects engaged in
the project employ designs that emphasize low-maintenance practices and obstacle-free
lawns, and minimize water usage for irrigation and impacts to existing native vegetation
where practicable.

(16) Picnic Tables

Provide one picnic table for every ten passenger car parking stalls, with a minimum
of four tables per SRA where practicable. Provide shelters for 50% of the picnic
tables on-site. Provide windscreens for picnic tables exposed to frequent high winds.
Each SRA is required to provide a minimum of one picnic table that complies with
ADAAG requirements. Place picnic tables near walkways but also provide privacy
from restroom users.

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Safety Rest Areas Chapter 1710

Variables (ft)
Ø A B C D E
Restroom 30˚ 85 30 50 30 100
35˚ 90 35 55 35 105
(typical location)
40˚ 95 35 60 35 110
Pavement marking 45˚ 100 45 65 45 115
100'
for parking stalls
A
20' min*

20' min

'
15
'
15

20' min
C E
A
Ø
'
20

D
A
* If exit ramp is tangent or has curve radii greater than 1,000', this width may be reduced to 14'.

Curb usage optional

Building
location

0.02'/ft 0.02'/ft

Section A-A

Curb usage optional

Building
location

0.02'/ft

Section A-A
Alternate

Typical Truck Storage

Exhibit 1710-5

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Chapter 1710 Safety Rest Areas

(17) Recreation Trails

Provide trails or nature walks where practicable. (See Chapter 1515 for more information
about shared-use paths.)

(18) Pet Areas

Provide ADAAG-compliant, well-lit areas for visitors to walk their pets away from
kiosks, plaza areas, and moving vehicles. Provide trash receptacles and pet waste
bags near pet areas.

(19) Electric Vehicle Charging Stations

Electric vehicle (EV) charging stations are provided at select sites. One ADAAG-
compliant parking stall with an accessible route is required when EV charging stations
are installed. Because EV charging is not the primary purpose of SRAs, locate the EV
parking stalls at the ends of the passenger vehicle parking area.

(20) Bicycle Facilities

Provide bicycle racks where this type of active transportation mode is accessible to
an SRA. (See Chapter 1520 for more information about roadway bicycle facilities.)

1710.06 Buildings
(1) Codes
Comply with current versions of the International Building Code, International Plumbing
Code, National Electric Code, Americans with Disabilities Act Accessibility Guidelines,
and all applicable state and local code requirements.

(2) Americans with Disabilities Act Accessibility Guidelines (ADAAG)

You must comply with accessibility guidelines specified in ADAAG for all building
components that are available to the public. Design restrooms, ancillary service buildings,
picnic benches, and information kiosks to ADAAG standards.

(3) Restroom Capacity

Provide a male/female restroom stall ratio of 40:60, and one unisex restroom that can be
opened to allow for daily cleaning operations where practicable. If the unisex restroom is
the only ADAAG-compliant toilet stall on-site, it must remain open at all times. Contact
the Capital Facilities Office for restroom standards and to verify the number of stalls that
should be provided at each site.

(4) Building Security

Design rest area buildings to provide a safe, comfortable experience for the traveling
public. Avoid building designs with potential hiding places, and ensure adequate building
lighting is provided around the perimeter.

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Safety Rest Areas Chapter 1710

(5) Building Sustainability

Buildings and systems are to adhere to the U.S. Green Building Council’s Leadership
in Energy and Environmental Design standards where practicable. Design facilities for
energy efficiency, water conservation, and low operational costs. Ensure materials are
durable and easy to maintain. Contact the Capital Facilities Office for minimum
requirements and standard details.

(6) Vandalism Mitigation

Consider vandal-resistant materials as a preferred option for building components such
as fixtures, fasteners, and surface coatings.

WSDOT Safety Rest Area Building – Adaptive Reuse Historic Preservation

Exhibit 1710-6

(7) Plaza Areas

Provide paved/concrete plaza areas at all new SRAs, where practicable, to enhance
safety, reduce wear and maintenance on heavy-travel areas, and provide unobstructed
pedestrian movement. Consider pedestrian movement when designing exterior fixtures
such as benches, kiosks, telephones, and vending machines in plaza areas. Avoid creating
potential hiding places and ensure appropriate lines of sight for safety.

(8) Building Signage

Ensure building signage meets current standards for rest area signage. Contact the Capital
Facilities Office for details.

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Chapter 1710 Safety Rest Areas

(9) Kiosks
Install travel information kiosks at all Interstate rest areas and at non-Interstate rest areas
as needed. A kiosk is usually equipped with backlit information displays.

(10) Volunteer Refreshment and Coffee Services

Construct volunteer services buildings at all Interstate rest areas and at non-Interstate rest
areas as needed. They can usually be incorporated with the travel information kiosks.
Wire, plumb, and heat these buildings to meet building codes as an occupied space.
Locate these buildings to give volunteers an unobstructed view of restroom entrances
and parking areas if feasible.

(11) Rehabilitation and Expansion

Minor renovation projects to address specific building and system deficiencies such as
roofs, interior fixtures and partitions, wall and floor surfaces, HVAC, electrical, water,
and sewer will extend the usefulness of the building and minimize maintenance and
operations costs. When major renovations are needed, consider restroom capacity
increases to meet current standards based on expected user volumes.
Other facility components that will eventually need rehabilitation are kiosks, irrigation
systems, sidewalks, picnic tables, parking areas, and RV dump stations. All projects must
meet current ADAAG building and site requirements. Consider efficiency improvements
that can be made to reduce operational costs. Coordinate with the Capital Facilities Office
for all renovation or expansion projects.

1710.07 Utilities
Contact the region Utilities Office for acquisition of Utility Service Agreements for
any utility needs. Coordinate with the Capital Facilities Office for long-term planning
considerations. Telephones are provided at most SRAs and must meet ADAAG
requirements. Because of the availability of cellular phones, and due to vandalism
and other reasons, public telephone service may be cancelled after coordination
between the Capital Facilities Office and region Maintenance.

(1) Power Capacity

A new or upgraded electrical service provided on-site will meet the projected needs
of the facility over the next 20 years where practicable. Provide three-phase service
where available. Consider building capacity increases, site lighting improvements,
electric vehicle charging stations, truck parking electrification, and other potential
needs. Contact the Capital Facilities Office for site-specific details or master plans.

(2) Water & Sewer Systems

Refer to the Hydraulics Manual for information on water and sewage disposal systems,
including reservoirs, long-distance pressure sewers, septic tanks, drainfields, and sewage
lagoons. Install separate water meters to quantify irrigation, building, RV dump stations,
and source water where practicable. Consider maintenance needs for water and sewer
system designs. Coordinate with the Capital Facilities Office for all issues related to
water and sewer systems at SRAs.

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Safety Rest Areas Chapter 1710

(3) Stormwater Systems

Stormwater management and treatment systems are to meet the guidelines and requirements
of the National Pollutant Discharge Elimination System (NPDES). Ensure runoff from
impervious surfaces at SRAs is managed on-site using typical best management practices.
Contact the Hydraulics Office for specific design recommendations, and the Maintenance
Operations Office for specific site requirements noted in the statewide NPDES permit.

(4) Future Utilities

Provide sleeves and conduits for future utilities in accordance with the site master plan
for water, sewer, power, and telephone. Address site-specific agreements by coordinating
with region Maintenance, utility companies, the Capital Facilities Office, and others
during site design.

1710.08 Documentation
(1) Design Documentation Checklist
For the list of documents required to be preserved in the Design Documentation Package
and the Project File, see the Design Documentation Checklist:
 www.wsdot.wa.gov/design/projectdev/
Also, coordinate design documentation with the Capital Facilities Office for any SRA
design projects.

(2) Environmental Documentation and Permitting

Coordinate with the appropriate environmental support personnel or region Environmental
Office during the planning and design stages of the project to determine what environmental,
cultural, or historical documentation will be required. Environmental staff will determine
applicable exemptions and required environmental permits for project delivery.

(3) Permanent Safety Rest Area Closures

Safety rest areas may be closed permanently or relocated. Federal Highways Administration
approval is required for any closure or transfer of such facilities to other federal, state, or
local agencies. Detailed closure procedures are stated in 23 CFR 752. Coordinate with the
Capital Facilities Office for proposal to close any WSDOT SRA.

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Chapter 1720 Weigh Sites
1720.01 General
1720.02 Definitions
1720.03 Planning, Development, and Responsibilities
1720.04 Permanent Facilities
1720.05 Portable Facilities
1720.06 Shoulder Sites
1720.07 Federal Participation
1720.08 Procedures
1720.09 Documentation

1720.01 General
Truck weighing facilities are needed to protect state highways from overweight vehicles, to
provide for vehicle safety inspection, and to provide a source of data for planning and research.
The development, construction, and maintenance of these facilities is a cooperative effort
between the WSDOT and the Washington State Patrol (WSP).

1720.02 Definitions
Note: For definitions of roadway, traveled way, lane, median, outer separation, shoulder,
decision sight distance, sight distance, and stopping sight distance, see the Glossary.

Commercial Vehicle Information Systems and Networks (CVISN) A network that links
intelligent transportation systems (ITS) to share information on commercial vehicles. When in
operation at a weigh site, it can enable commercial vehicles to clear the facility without
stopping.

Frontage road: An auxiliary road that is a local road or street located beside a highway for
service to abutting property and adjacent areas and for control of access.

Static scale: A scale that requires a vehicle to stop for weighing.

Usable shoulder: The width of the shoulder that can be used by a vehicle for stopping.

Weigh in motion (WIM): A scale facility capable of weighing a vehicle without the vehicle
stopping.

1720.03 Planning, Development, and Responsibilities

The WSP works with WSDOT Strategic Planning and Programming to develop a prioritized list of
weigh facility needs for each biennium. The list includes:
 New permanent facilities.
 New portable facilities.
 New shoulder sites.
 WIM equipment.

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Weigh Sites Chapter 1720

 Vehicle inspection facilities.

 Scale approach slab reconstruction.

The WSP provides the Program Management Office of Strategic Planning and Programming a
Project Definition, which includes:
 A statement of need, the purpose of the project, and the type of work.
 The general location of the project.

Program Management sends this information to the region for preparation of a Project
Summary. The region works with the WSP to identify the specific location of the facility. The
region then prepares a design decision estimate and submits it to Program Management.

The region negotiates and the Regional Administrator executes any formal agreements with the
WSP required for the design, construction, or maintenance of vehicle weighing and inspection
facilities.

The Memorandum of Understanding Related to Vehicle Weighing and Equipment: Inspection

Facilities on State Highways, Exhibit 1720-8, contains details about the various responsibilities of
WSDOT and the WSP.

1720.04 Permanent Facilities

Permanent truck weighing facilities have permanent scales and may have buildings. When these
facilities are in operation, trucks are required stop. However, when Weigh In Motion (WIM) and
Commercial Vehicle Information Systems and Networks (CVISN) capabilities have been installed,
the driver may be notified to continue without stopping. The notification to continue may be
through the use of signs or transponders.

1720.04(1) Site Locations

The exact location of a truck weighing facility is generally controlled by topography, highway
alignment, and geometrics. It is also desirable to select a site where adequate right of way is
already available. Select the most economical site to minimize site preparation, expense, and
impact on the environment. Water, electricity availability, and sewage treatment and disposal
are other considerations for site selection. Additionally, use the following criteria:
 Locate the facility such that its operation will not hinder the operation of the
highway or other related features such as intersections and interchanges.
 To the extent feasible, eliminate options for truck traffic to bypass the weigh site.
 Base the site selection on the type and volume of trucks using the route.

An Access Revision Report (ARR) is required for weigh sites on multilane divided highways with
access control (see Chapter 550).

1720.04(2) Design Features

On multilane highways, provide off- and on-connections as shown in Chapter 1360. Exhibit
1720-1 is the minimal design of a weigh site on multilane highways.

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Chapter 1720 Weigh Sites

Design weigh facilities on two-lane highways to best fit the existing conditions, with particular
consideration given to the matter of access to and from the site. Off- and on-connections, as
shown in Chapter 1360, are preferred. However, with justification, on-connections may be
designed as intersections (see Chapter 1310). Exhibit 1720-2 is a guide for the design of weigh
sites on two-lane highways.

The following special design features apply to weigh sites:

 Level cement concrete approach slabs are required at both ends of the scales.
 Hot mix asphalt (HMA) approach slabs will be allowed only when adequate soil
conditions exist, projected truck volume is light, and benefit/cost analysis justifies
the HMA based on the small percentage of time the scales will be in operation.
 The approach slabs must be level and in the same plane as the scale.
 Provide adequate parking and storage to ensure trucks do not impede the main line
through traffic. The WSDOT Regional Administrator and the WSP agree on the area
to be provided.
 On multilane divided highways, install illuminated electronically controlled “open”
and “closed” message signs that can be operated from the scalehouse or the control
cabinet. Provide permanent signing for the facility, as requested by the WSP.
 The need for a vehicle safety inspection facility at any site is identified by the WSP.
Exhibit 1720-3 is a guide for a site plan for a single-bay vehicle inspection facility.
Additional bays and site adaptation will be on a site-by-site basis. The WSDOT
Regional Administrator and the WSP agree on the area to be provided.
 The need for some form of approach protective treatment for the scale house or
a protective fence between the scale and roadway is identified by the WSP and
agreed upon by the WSDOT Regional Administrator and the WSP. The need for the
device is to protect the scale house from errant vehicles. (See Chapter 1600 for
additional clear zone considerations.)
 The need for WIM or CVISN capabilities is identified by the WSP. Design the in-place
facilities to provide the ability to notify drivers whether to continue on or to stop for
further investigation before they reach the exit for the static scale. The design is
agreed upon by the WSDOT Regional Administrator and the WSP.
 When WIM and CVISN are not included in the project, provide conduit for their
future installation.
 With justification, at locations where space is limited, the depressed outer
separation between the weigh facility and the through lanes may be replaced with
concrete traffic barrier. (See the Collector-Distributor: Outer Separations exhibit in
Chapter 1360.)
 Provide a clear view of the entire weigh site for the facility’s operator and the driver
of an approaching vehicle.
 Hot mix asphalt is acceptable for use on the ramp and storage areas. Design the
depth in accordance with the surfacing report.

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Weigh Sites Chapter 1720

 To optimize scale efficiency, make the storage area flat; however, to facilitate
drainage, the slope may be up to 2%.
 Provide illumination when requested by the WSP. Illumination is required if the
facility is to be operated during the hours of darkness and may be desirable at other
locations to deter unauthorized use of the facility. (See Chapter 1040 for additional
information on illumination.)

1720.05 Portable Facilities

Portable truck weighing facilities have no permanent scales or buildings. When these facilities
are in operation, they operate in the same manner as permanent facilities.

1720.05(1) Site Locations

Design portable truck weighing facilities located on two-lane and multilane roadways to best fit
the existing conditions. Minor portable scale sites, as shown in Exhibit 1720-4, are used with
two-way traffic and on multilane highways with low traffic volumes. Major portable scale sites
(see Exhibit 1720-5) are for use on expressways, freeways, and where traffic volumes are high.

Locate the weighing facility such that its operation will not hinder the operation of the highway
or other related features such as intersections.

An ARR is required for weigh sites on multilane divided highways with access control (see
Chapter 550).

1720.05(2) Design Features

The following special design features apply to portable facilities:

 Off- and on-connections, as shown in Exhibits 1720-4 and 1720-5, are preferred;
however, with justification on highways with no access control, on-connections may
be designed as intersections (see Chapter 1310).
 With justification, at locations where space is limited, the depressed outer
separation between the weigh facility and the through lanes may be replaced with
concrete traffic barrier. (See the Collector-Distributor: Outer Separation exhibit in
Chapter 1360.)
 Provide adequate parking and storage to ensure trucks do not impede the main line
through traffic. The WSDOT Regional Administrator and the WSP agree on the area
to be provided.
 Hot mix asphalt is acceptable for use on the ramp and storage areas. Design
the depth in accordance with the surfacing report.
 To optimize portable scale efficiency, make the storage area flat; however,
to facilitate drainage, the slope may be up to 2%.
 Provide permanent signing for the facility, as requested by the WSP.
 Provide illumination when requested by the WSP. Illumination is required if the
facility is to be operated during the hours of darkness and may be desirable at other

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Chapter 1720 Weigh Sites

locations to deter unauthorized use of the facility. (See Chapter 1040 for additional
information on illumination.)

1720.06 Shoulder Sites

Shoulder sites are used by the WSP to pull a truck over for inspection and weighing with
portable scales.

1720.06(1) Site Locations

Design shoulder sites to best fit the existing conditions. Small shoulder sites (see Exhibit 1720-6)
are for use on lower-volume roadways (ADT 5000 or less) with two-way traffic. Large shoulder
sites (see Exhibit 1720-7) are to be used with higher-volume two-way roadways and multilane
highways. Locate the weighing facility so that its operation will not hinder the operation of the
highway or other related features such as intersections.

1720.06(2) Design Features

Shoulder sites are designed in coordination with the WSP. Input from the local WSP Commercial
Vehicle Enforcement personnel will ensure the proposed site will meet their needs without
over-building the facility. Obtain written concurrence from the WSP for the length, width, and
taper rates before the design is finalized.

When the ADT is 1,500 or less, and with the written approval of the WSP, the tapers at small
shoulder sites may be eliminated. The shoulders on either side of the site may be used as
acceleration and deceleration lanes, whether or not they were designed for this use. Therefore,
provide adequate strength to support truck traffic.

Hot mix asphalt is acceptable for use on all shoulder sites. Design the depth in accordance with
the surfacing report. Design the shoulder pavement at this depth for a length not less than the
deceleration lane length before, and the acceleration lane length after, the site (see Chapter
1360).

When the shoulders are designed to be used for deceleration and acceleration lanes, the
minimum width is 12 feet with full pavement depth for the deceleration/ acceleration lane
lengths (see Chapter 1360).

Use a maximum 2% slope in order to optimize portable scale efficiency and facilitate drainage.

1720.07 Federal Participation

Federal funds appropriate to the system being improved may be used for the acquisition of right
of way and the construction of truck weighing facilities and vehicle inspection facilities. This
includes, but is not limited to, on- and off-ramps, deceleration/acceleration lanes, passing lanes,
driveways, parking areas, scale approach slabs, vehicle inspection facilities, roadway
illumination, and signing.

1720.08 Procedures
Prepare site plans for all truck weighing facilities that include:
 Class of highway and design speed for main line (see Chapter 1103).

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Weigh Sites Chapter 1720

 Curve data on main line and weigh site.

 Number of lanes and width of lanes and shoulders on main line and weigh site.
 Superelevation diagrams for the main line and weigh site.
 Stationing of ramp connections and channelization.
 Illumination.
 Signing.
 Water supply and sewage treatment.
 Roadside development.

Get WSP approval of the site plans before the final plan approval.

1720.09 Documentation
Refer to Chapter 300 for design documentation requirements.

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Chapter 1720 Weigh Sites

Exhibit 1720-1 Truck Weigh Site: Multilane Highways

On-connection (See Chapter 1360)

(See Chapter 1360)

WSDOT Design Manual M 22-01.17 Page 1720-7

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Weigh Sites Chapter 1720

Exhibit 1720-2 Truck Weigh Site: Two-Lane Highways

(See Chapter 1360)

(See Chapter 1360)

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 Chapter 1720

September 2019
WSDOT Design Manual M 22-01.17
Edge of pavement
E
D
20 ft 15 ft
ft
Exhibit 1720-3 Vehicle Inspection Installation

50

ft
5 0 in C B A
A Truck storage and parking m 50
ft 100 ft typ
B Outside truck inspection and parking
70
C Truck inspection building ft 20 ft 50 ft min (typ)
D Scalehouse
E Scale
Edge of pavement
Weigh Sites

Page 1720-9
Weigh Sites Chapter 1720

Exhibit 1720-4 Minor Portable Scale Site

Edge of through lane 20 ft

2 ft 4 ft

Match
1
10 min
4 ft

line
15 ft
10 ft 15 ft

300 ft min

(Not to Scale)

Edge of through lane 2 ft

line

1
Match

25 min

15 ft 8 ft

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Chapter 1720 Weigh Sites

Exhibit 1720-5 Major Portable Scale Site

R = 6 ft
Edge of through lane 34 ft
2 ft 4 ft

Match
1
15 min
4 ft

line
15 ft

10 ft 15 ft

300 ft min

(Not to Scale)

R = 4 ft
10 ft Edge of through lane 2 ft
line

1
Match

50

15 ft 8 ft

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Weigh Sites Chapter 1720

Exhibit 1720-6 Small Shoulder Site

Optional Travel lane Optional

(see text) (see text)

20 ft

1 1
15 15

200 ft min
Length to be established by
agreement with the WSP, but not
less than 200 feet

Exhibit 1720-7 Large Shoulder Site

Travel lane

20 ft
1 1
15 25

300 ft min

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Chapter 1720 Weigh Sites

Exhibit 1720-8 MOU Related to Vehicle Weighing and Equipment: Inspection Facilities on State
Highways

WSDOT Design Manual M 22-01.17 Page 1720-13

September 2019
Weigh Sites Chapter 1720

Exhibit 1720-8 (continued) MOU Related to Vehicle Weighing and Equipment: Inspection Facilities
on State Highways

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Chapter 1720 Weigh Sites

Exhibit 1720-8 (continued) MOU Related to Vehicle Weighing and Equipment: Inspection Facilities
on State Highways

WSDOT Design Manual M 22-01.17 Page 1720-15

September 2019
Weigh Sites Chapter 1720

Exhibit 1720-8 (continued) MOU Related to Vehicle Weighing and Equipment: Inspection Facilities
on State Highways

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Chapter 1720 Weigh Sites

Exhibit 1720-8 (continued) MOU Related to Vehicle Weighing and Equipment: Inspection Facilities
on State Highways

WSDOT Design Manual M 22-01.17 Page 1720-17

September 2019
Weigh Sites Chapter 1720

Exhibit 1720-8 (continued) MOU Related to Vehicle Weighing and Equipment: Inspection Facilities
on State Highways

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Exhibit 1720-8 (continued) MOU Related to Vehicle Weighing and Equipment: Inspection Facilities
on State Highways

WSDOT Design Manual M 22-01.17 Page 1720-19

September 2019
Weigh Sites Chapter 1720

Exhibit 1720-8 (continued) MOU Related to Vehicle Weighing and Equipment: Inspection Facilities
on State Highways

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Chapter 1720 Weigh Sites

Exhibit 1720-8 (continued) MOU Related to Vehicle Weighing and Equipment: Inspection Facilities
on State Highways

WSDOT Design Manual M 22-01.17 Page 1720-21

September 2019
Weigh Sites Chapter 1720

Exhibit 1720-8 (continued) MOU Related to Vehicle Weighing and Equipment: Inspection Facilities
on State Highways

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Chapter 1720 Weigh Sites

Exhibit 1720-8 (continued) MOU Related to Vehicle Weighing and Equipment: Inspection Facilities
on State Highways

WSDOT Design Manual M 22-01.17 Page 1720-23

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Weigh Sites Chapter 1720

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 Glossary

Acronyms

Glossary of Terms

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July 2018
 Acronyms
AADT Annual average daily traffic HSS Highways of Statewide Significance
ACT Alternatives Comparison Table ICD Inscribed circle diameter
ADA Americans with Disabilities Act of 1990 ICE Intersection Control Evaluation
ADT Annual daily traffic ITS Intelligent transportation systems
ALJ Administrative law judge L/A Limited access
AOS Apparent opening size LOS Level of service
APS Accessible pedestrian signal MEF Maximum extent feasible
ARR Access Revision Report MOU Memorandum of Understanding
AWDVTE Average weekday vehicle trip ends MPO Metropolitan Planning Organization
B/C Benefit / cost NEPA National Environmental Policy Act
BLM Bureau of Land Management NHS National Highway System
BOD Basis of Design PAR Pedestrian access route
BRT Bus rapid transit PCP Pedestrian circulation path
BST Bituminous surface treatment PEL Planning and Environmental Linkage
CAR Crash Analysis Report PF Project File
CE Categorical Exemption (SEPA) PoDI Project of Division Interest (FHWA)
CE Categorical Exclusion (NEPA) PS Project Summary
CFA Contributing Factors Analysis PSF Pounds per square foot
CFR Code of Federal Regulations PS&E Plans, Specifications, and Estimates
CGT Continuous Green “T” intersection QOL Quality of Service
CIPP Capital Improvement and Preservation R/W Right of way
Program
CPMS Capital Program Management System RCUT Restricted Crossing U Turn
CRT Controlled releasing terminal post RCW Revised Code of Washington
CSS Context sensitive solutions RFP Request for Proposal
CTR Commute Trip Reduction ROD Record of Decision
CVISN Commercial Vehicle Inf. System and RTIP Regional Transportation Improvement Program
Networks
DDHV Directional design hour volume RTPO Regional Transportation Planning Organization
DDI Diverging Diamond Interchange SEPA [Washington] State Environmental Policy Act
DDP Design Documentation Package SHS Sustainable Highway Safety
DHV Design hourly volume SHSP Strategic Highway Safety Plan
DLT Displaced Left Turn SIMMS Signal Maintenance Management System
DNS Determination of Nonsignificance (SEPA) SOV Single-occupant vehicle
DS Determination of Significance (SEPA) SRA Safety rest area
E&EP Environmental & Engineering Programs SPUI Single Point Urban Interchange
Division
EA Environmental Assessment (NEPA) STIP Statewide Transportation Improvement Program
EIS Environmental Impact Statement STP Surface Transportation Program
ERS Environmental Review Summary TIA Traffic Impact Analysis
FGTS Freight and Goods Transportation System TIP Transportation Improvement Program
FHWA Federal Highway Administration TMA Transportation Management Area
FONSI Finding of No Significant Impact (NEPA) TMP Transportation management plan
FTA Federal Transit Administration TWLTL Two-way left-turn lane
GIS Geographic Information System UPO [Central Puget Sound] Urban Planning Office
GMA Growth Management Act USC United States Code
HCM Highway Capacity Manual VE Value engineering
HCP Highway Construction Program VECP Value Engineering Change Proposal
HMA Hot mix asphalt VIC Visitor Information Center
HOT High-occupancy toll VPH Vehicles per hour
HOV High-occupancy vehicle WAC Washington Administrative Code
HQ WSDOT’s Headquarters in Olympia WIM Weigh in motion
HSM Highway Safety Manual WSDOT Washington State Department of Transportation
HSP Highway System Plan WSPMS Washington State Pavement Management System
WTP Washington Transportation Plan

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 Glossary

Glossary of Terms

A B C D E F G H I J K L M N O P Q R S T U V W Y Z

access A means of entering or leaving a public road, street, or highway with respect to abutting
property or another public road, street, or highway.

access break Any point from inside or outside the state limited access right of way limited access
hachures that crosses over, under, or physically through the plane of the limited access, is an access
break or “break in access,” including, but not limited to, locked gates and temporary construction access
breaks.

access connection An access point, other than a public road/street, that permits access to or from a
managed access highway on the state highway system.

access connection permit A written authorization issued by the permitting authority for a specifically
designed access connection to a managed access highway at a specific location; for a specific type and
intensity of property use; and for a specific volume of traffic for the access connection based on the final
stage of the development of the applicant’s property. The actual form used for this authorization is
determined by the permitting authority.

access control The limiting and regulating of public and private access to Washington State’s highways,
as required by state law. A design control (see Chapter 1103) – there are two categories of controlling
access to state highways limited access and managed access.

Access Control Tracking System Limited Access and Managed Access Master Plan A database list,
related to highway route numbers and mileposts, that identifies either the level of limited access or the
class of managed access:  www.wsdot.wa.gov/design/accessandhearings

access density The number of access points (driveways) per mile.

access design analysis A design analysis (see Chapter 300) that authorizes deferring or staging
acquisition of limited access control, falling short of a 300-foot requirement, or allowing an existing
access point to stay within 130 feet of an intersection on a limited access highway. Approval by the
Director & State Design Engineer, Development Division, or designee, is required (see Chapter 530).

access hearing plan A limited access plan prepared for presentation at an access hearing.

access management The programmatic control of the location, spacing, design, and operation of
driveways, median openings, interchanges, and street connections to a roadway.

access point Any point that allows private or public entrance to or exit from the traveled way of a state
highway, including “locked gate” access and maintenance access points.

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Glossary

access point revision A new access point or a revision of an existing interchange/ intersection
configuration. Locked gates and temporary construction breaks are also access point revisions.

access point spacing On a managed access highway, the distance between two adjacent access points
on one side of the highway, measured along the edge of the traveled way from one access point to the
next (see also corner clearance).

access revision report (ARR) A technical report which documents specific analyses in order to approve
or reject a proposed revision to freeway access. See Chapter 550.

access report plan A limited access plan prepared for presentation to local governmental officials at
preliminary meetings before preparation of the access hearing plan.

access rights Property rights that allow an abutting property owner to enter and leave the public
roadway system.

accessible Usable by persons with disabilities (ADA compliant). (ADA term)

accessible pedestrian signal (APS) A device that communicates information about the “WALK”
phase in audible and vibrotactile (vibrating surface that communicates information through touch,
located on the accessible pedestrian signal button) formats. (ADA term)

accessible route See pedestrian access route. (ADA term)

ADA An abbreviation for the Americans with Disabilities Act of 1990. The ADA is a civil rights
law that identifies and prohibits discrimination based on disability. Title II of the ADA requires public
entities to design new pedestrian facilities or alter existing pedestrian facilities to be accessible to and
usable by people with disabilities. (ADA term)

adaptive lighting system A lighting system with a control system connected, allowing for dimming,
on/off operation by time of night, and independent scheduling of individual lights for select hours of
operation during nighttime hours.

affidavit of publication A notarized written declaration stating that a notice of hearing (or notice of
opportunity for a hearing) was published in the legally prescribed manner.

affidavit of service by mailing A notarized written declaration stating that the limited access hearing
packet was mailed at least 15 days prior to the hearing and entered into the record at the hearing.

alteration A change to a facility in the public right of way that affects or could affect access,
circulation, or use. Alterations include, but are not limited to: renovation; rehabilitation; reconstruction;
historic restoration; resurfacing of circulation paths or vehicular ways; or changes or rearrangement of
structural parts or elements of a facility. Alterations do not include: Spot pavement repair; liquid-asphalt
sealing, chip seal (bituminous surface treatment), or crack sealing; or lane restriping that does not alter
the usability of the shoulder. (ADA term)

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 Glossary

alternative(s) Possible solutions to accomplish a defined purpose and need. These include local and
state transportation system mode and design options, locations, and travel demand management and
transportation system management-type improvements such as ramp metering, mass transit, and high-
occupancy vehicle (HOV) facilities.

Alternatives Comparison Table (ACT) A table that documents and presents the tradeoffs among those
performance metrics identified for each alternative under consideration on a project. The ACT is used to
assist in analyzing the baseline and contextual performance tradeoffs and ultimately to select an
alternative. It is a supplemental document to the “Alternatives Analysis” section of the Basis of Design.

ancillary services Those secondary services, also considered amenities, provided at safety rest areas
that include, but are not limited to, vending machines, picnic areas, interpretive signing, telephones,
recreational vehicle (RV) sanitary disposal facilities, trails, scenic viewpoints, commercial and public
information displays, and visitor information centers.

annual average daily traffic (AADT) The total volume of traffic passing a point or segment of a
highway facility in both directions for one year divided by the number of days in the year. Normally,
periodic daily traffic volumes are adjusted for hours of the day counted, days of the week, and seasons
of the year to arrive at average annual daily traffic.

annual daily traffic (ADT) The average 24 hour volume, being the total volume during a stated period
divided by the number of days in that period. Normally, this would be periodic daily traffic volumes over
several days, not adjusted for days of the week or seasons of the year.

approach An access point, other than a public road/street, that allows access to or from a limited
access highway on the state highway system.

approach and access connection These terms are listed under the specific access section to which they
apply. The first section below is for limited access highways and uses the term approach. The second
section below is for managed access highways and uses the term access connection. Approaches and
access connections include any ability to leave or enter a highway right of way other than at an
intersection with another road or street.

(a) limited access highways: approach An access point, other than a public road/street, that allows
access to or from a limited access highway on the state highway system. There are five types of
approaches to limited access highways that are allowed:
 Type A An off and on approach in a legal manner, not to exceed 30 feet in width, for the
sole purpose of serving a single-family residence. It may be reserved by the abutting owner
for specified use at a point satisfactory to the state at or between designated highway
stations. This approach type is allowed on partial and modified control limited access
highways.
 Type B An off and on approach in a legal manner, not to exceed 50 feet in width, for use
necessary to the normal operation of a farm, but not for retail marketing. It may be reserved
by the abutting owner for specified use at a point satisfactory to the state at or between
designated highway stations. This approach type is allowed on partial and modified control
limited access highways. This approach type may be used for wind farms when use of the

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Glossary

approach is limited to those vehicles necessary to construct and maintain the farm for use in
harvesting wind energy.
 Type C An off and on approach in a legal manner, for a special purpose and width to be
agreed upon. It may be specified at a point satisfactory to the state at or between
designated highway stations. This approach type is allowed on partial and modified control
limited access highways and on full control limited access highways where no other
reasonable means of access exists, as solely determined by the department.
 Type D An off and on approach in a legal manner, not to exceed 50 feet in width, for use
necessary to the normal operation of a commercial establishment. It may be specified at a
point satisfactory to the state at or between designated highway stations. This approach
type is allowed only on modified control limited access highways.
 Type E This type is no longer allowed to be constructed because of the requirements that
there be only one access point per parcel on a limited access state highway.
 Type F An off and on approach in a legal manner, not to exceed 30 feet in width, for the
sole purpose of serving a wireless communication site. It may be specified at a point
satisfactory to the state at or between designated highway stations. This approach type is
allowed only on partial control limited access highways. (See WAC 468 58 080(vi) for further
restrictions.)
(b) managed access highways: access connection An access point, other than a public road/street,
that permits access to or from a managed access highway on the state highway system. There are
five types of access connection permits:
 conforming access connection A connection to a managed access highway that meets
current WAC and WSDOT location, spacing, and design criteria.
 grandfathered access connection Any connection to the state highway system that was in
existence and in active use on July 1, 1990, and has not had a significant change in use.
 joint-use access connection A single connection to a managed access highway that serves
two or more properties.
 nonconforming access connection A connection to a managed access highway that does
not meet current WSDOT location, spacing, or design criteria, pending availability of a future
conforming access connection.
 variance access connection A connection to a managed access highway at a location not
normally allowed by current WSDOT criteria.
(c) managed access connection category There are four access connection permit categories for
managed access connections to state highways: Category I, Category II, Category III, and Category IV
(see Chapter 540).

area of influence The area that will be directly impacted by the proposed action: freeway main line,
ramps, crossroads, immediate off-system intersections, and state and local roadway systems.

articulated bus A two-section bus that is permanently connected at a joint.

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 Glossary

auxiliary aids and services (1) Qualified interpreters, notetakers, transcription services, written
materials, telephone handset amplifiers, assistive listening devices, assistive listening systems,
telephones compatible with hearing aids, open and closed captioning, telecommunications devices for
persons with hearing or speech difficulties (TDDs), videotext displays, or other effective methods for
making aurally delivered materials available to individuals with hearing limitations; (2) Qualified readers,
taped texts, audio recordings, Brailled materials, large print materials, or other effective methods for
making visually delivered materials available to individuals with visual impairments; (3) Acquisition or
modification of equipment or devices; (4) Other similar services and actions; and (5) Providing and
disseminating information, written materials, and notices in languages other than English, where
appropriate.

auxiliary lane The portion of the roadway adjoining the through lanes for parking, speed change,
turning, storage for turning, weaving, truck climbing, and other purposes supplementary to through-
traffic movement.

average light level The average of all light intensities within the design area.

average weekday vehicle trip ends (AWDVTE) The estimated total of all trips entering plus all trips
leaving a road approach on a weekday for the final stage of development of the property served by the
road approach.

backslope A sideslope that goes up as the distance increases from the roadway (cut slopes).

barrier terminal A crash-tested end treatment for longitudinal barriers that is designed to reduce the
potential for spearing, vaulting, rolling, or excessive deceleration of impacting vehicles from either
direction of travel. Barrier terminals include applicable anchorage.

baseline The approved time phased plan (for a project, a work breakdown structure component, a
work package, or a schedule activity), plus or minus approved project scope, cost, schedule, and
technical changes. Generally refers to the current baseline, but may refer to the original or some other
baseline. Usually used with a modifier (e.g., cost baseline, schedule baseline, performance measurement
baseline, technical baseline).

baseline performance metric A description of need in terms that can be measured or assessed in both
the existing and proposed (future) state.

baseline performance need The primary reason a project has been proposed. It refers to the threshold
determination at the project location resulting from a statewide biennial prioritization and funding
process. It may also be the specific issue to be addressed by the project described by a partnering
agency that is providing the funding.

basic number of lanes The minimum number of general purpose lanes designated and maintained
over a significant length of highway.

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Glossary

Basis of Design (BOD) A document and template used to record information, decisions, and analysis
needed in the development of a project design, including all factors leading to the development and
selection of a project alternative, and the selection of design elements associated with that alternative.

benefit/cost analysis A method of valuing a proposition by first monetizing all current expenditures to
execute―cost―as well as the expected yields into the future―benefit, then dividing the total benefit by
the total cost, thus providing a ratio. Alternatives may be rendered and compared in this fashion where,
typically, a higher ratio is preferable, indicating a better return on investment.

bicycle Any device propelled solely by human power upon which a person or persons may ride, having
two tandem wheels, either of which is 16 inches or more in diameter, or three wheels, any one of which
is more than 20 inches in diameter.

bicycle route A system of facilities that is used or has a high potential for use by bicyclists or that is
designated as such by the jurisdiction having the authority. A series of bicycle facilities may be combined
to establish a continuous route and may consist of any or all types of bicycle facilities.

bike lane A portion of a highway or street identified by signs and pavement markings as reserved for
bicycle use.

buffer A space measured from the back of the curb to the edge of the sidewalk that could be treated
with plantings or alternate pavement, or be used for needs such as drainage treatment or utility
placement. (ADA term)

buffer-separated HOV lane An HOV lane that is separated from the adjacent same direction general-
purpose freeway lanes by a designated buffer.

bus A rubber-tired motor vehicle used for transportation, designed to carry more than ten passengers.

business access transit (BAT) lanes A transit lane that allows use by other vehicles to access abutting
businesses.

bus pullout A bus stop with parking area designed to allow transit vehicles to stop wholly off the
roadway.

bus rapid transit (BRT) An express rubber tired transit system operating predominantly in roadway
managed lanes. It is generally characterized by separate roadway or buffer-separated HOV lanes, HOV
direct access ramps, and a high-occupancy designation (3+ or higher).

bus shelter A facility that provides seating and protection from the weather for passengers waiting for
a bus.

bus stop A place designated for transit vehicles to stop and load or unload passengers.

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 Glossary

capacity The maximum sustainable flow rate at which vehicles or persons can reasonably be expected
to traverse a point or uniform segment of a lane or roadway during a specified time period under given
roadway, geometric, traffic, environmental, and control conditions. Capacity is usually expressed as
vehicles per hour (vph), passenger cars per hour (pcph), or persons per hour (pph).

Capital Improvement and Preservation Program (CIPP) WSDOT’s program of projects developed each
biennium that delivers capital investments in highway, marine, and rail facilities that have been funded
in part or in whole by the state Legislature. The CIPP is submitted to the Governor and, ultimately, by
the Governor to the Legislature.

Categorical Exclusion (CE) (NEPA) or Categorical Exemption (CE) (SEPA) Actions that do not
individually or cumulatively have a significant effect on the environment.

central island The area of the roundabout, including the truck apron, surrounded by the circulating
roadway.

central island diameter The diameter of the central island, including the truck apron (see Chapter
1320).

circulating lane A lane used by vehicles circulating in the roundabout.

circulating roadway The traveled lane(s) adjacent to the central island and outside the truck apron,
including the entire 360° circumference of the circle.

circulating roadway width The total width of the circulating lane(s) measured from inscribed circle to
the central island (see Chapter 1320).

clear run-out area The area beyond the toe of a nonrecoverable slope available for use by an errant
vehicle.

clear width The unobstructed width within a pedestrian circulation path. The clear width within a
pedestrian circulation path must meet the accessibility criteria for a pedestrian access route. (ADA term)

clear zone The total roadside border area, available for use by errant vehicles, starting at the edge of
the traveled way and oriented from the outside or inside shoulder (in median applications) as
applicable. This area may consist of a shoulder, a recoverable slope, a nonrecoverable slope, and/or a
clear run-out area. The clear zone cannot contain a critical fill slope, fixed objects, or water deeper than
2 feet.

climate change vulnerability The risk a transportation facility will be impacted by the effects of climate
change.

climbing lane An auxiliary lane used for the diversion of slow traffic from the through lane.

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collector A context description of a roadway intended to provide a mix of access and mobility
performance. Typically low speed, collecting traffic from local roads and connecting them with
destination points or arterials. This term is used in multiple classification systems, but is most commonly
associated with the Functional Classification System.

collector-distributor road (C-D road) A parallel roadway designed to remove weaving from the main
line and reduce the number of main line entrances and exits.

collector system Routes that primarily serve the more important intercounty, intracounty, and
intraurban travel corridors; collect traffic from the system of local access roads and convey it to the
arterial system; and on which, regardless of traffic volume, the predominant travel distances are shorter
than on arterial routes (RCW 47.05.021).

Commercial Vehicle Information Systems and Networks (CVISN) A network that links intelligent
transportation systems (ITS) to share information on commercial vehicles. When in operation at a weigh
site, it can enable commercial vehicles to clear the facility without stopping.

complex ramp alignment and grade As related to Chapter 1040 Illumination. The exit advisory speed
is 35 mph or lower than the posted main line speed, or there is a 6% or greater change in grade from
existing main line grade to the ramp grade.

conflict point A point where road user paths cross, merge, or diverge.

consider To think carefully about, especially in order to make a decision. The decision to document a
consideration is left to the discretion of the engineer.

construction impact zone The area in which an alteration to an existing facility takes place (also known
as the project footprint). If a crosswalk (marked or unmarked) will be reconstructed, paved
(overlay or inlay), or otherwise altered as part of a project, then the curb ramps that serve that
crosswalk are within the construction impact zone. (ADA term)

context Refers to the environmental, economic, and social features that influence livability and travel
characteristics. Context characteristics provide insight into the activities, functions, and performance
that can be influenced by the roadway design. Context also informs roadway design, including the
selection of design controls, such as target speed and modal priority, and other design decisions.
See Chapter 1102.

context categories The naming convention used to describe either a land use or transportation
context (see Chapter 1102).

context characteristic A distinguishing trait within a context, either land use or transportation. Chapter
1102 lists several common characteristics that help distinguish between one type of context versus
another. There may be additional traits not covered in the chapter.

contextual performance metric A restatement of a contextual performance need in terms that can be
measured or assessed in both the existing and proposed (future) state.

contextual performance need A statement of need that applies to a project location which has not
been identified as a baseline need.

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contiguous parcels Two or more pieces of real property, under the same ownership, with one or more
boundaries that touch and have similarity of use.

continuous load The electrical load on a circuit that lasts for a duration of three or more hours on any
day.

contributing factors Those operational conditions, human factors, context conditions, design
elements, design controls, or actions identified by data, engineering judgment, or the community that
contribute to a performance need under evaluation.

controlled releasing terminal (CRT) post A standard-length guardrail post that has two holes drilled
through it so it might break away when struck.

conventional traffic signal A permanent or temporary installation providing alternating right of way
assignments for conflicting traffic movements. At least two identical displays are required for the
predominant movement on each approach.

corner clearance On a managed access highway, the distance from an intersection of a public road or
street to the nearest access connection along the same side of the highway. The minimum corner
clearance distance (see Chapter 540) is measured from the closest edge of the intersecting road or
street to the closest edge of the traveled way of the access connection, measured along one side of the
traveled way (through lanes) (see also access point spacing).

corridor sketch An information source that describes the attributes of a state highway corridor, its
current and future function, as well as its performance expectations. It will ultimately identify cost-
effective strategies for future consideration. A completed corridor sketch may have information that is
valuable at the project level in determining contextual performance needs, and project alternatives. A
corridor sketch is not a substitute for detailed planning and analysis, nor is it a list of investments or
projects.

corridor vision The future transportation context from a regional perspective. Practical Design
considers and accounts for the contextual needs of the longer section of highway in the development
and evaluation of alternatives to ensure a favorable outcome for the greater system.

counter slope The slope of the gutter or roadway at the foot of a curb ramp or landing where it
connects to the roadway, measured along the axis of the running slope extended. (ADA term)

countermeasure An action taken to counteract an existing or anticipated condition.

court reporter A person with a license to write and issue official accounts of judicial or legislative
proceedings.

Crash Analysis Report (CAR) A template that is used for documenting required analysis for I-2
CAL/CAC/IAL projects, as described in Chapter 321.

critical fill slope A slope on which a vehicle is likely to overturn. Slopes steeper than 3H:1V are
considered critical fill slopes.

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Glossary

cross slope The slope measured perpendicular to the direction of travel. (ADA term)

crossroad The minor roadway at an intersection. At a stop-controlled intersection, the crossroad has
the stop.

crosswalk A marked or unmarked pedestrian crossing, typically at an intersection, that connects the
pedestrian access routes on opposite sides of a roadway. A crosswalk must meet accessibility criteria.
A crosswalk is also defined as:
 “…the portion of the roadway between the intersection area and a prolongation or
connection of the farthest sidewalk line or in the event there are no sidewalks then
between the intersection area and a line ten feet therefrom, except as modified by a
marked crosswalk” (RCW 46.04.160).
 “(a) That part of a roadway at an intersection included within the connections of the
lateral lines of the sidewalks on opposite sides of the highway measured from the curbs
or in the absence of curbs, from the edges of the traversable roadway, and in the
absence of a sidewalk on one side of the roadway, the part of the roadway included
within the extension of the lateral lines of the sidewalk at right angles to the center
line; (b) any portion of a roadway at an intersection or elsewhere distinctly indicated as
a pedestrian crossing by lines on the surface, which might be supplemented by
contrasting pavement texture, style, or color” (MUTCD, 2003; Guide for the Planning,
Design, and Operation of Pedestrian Facilities, AASHTO, 2004). (ADA term)

curb extension A curb and sidewalk bulge or extension out into the parking lane used to decrease the
length of a pedestrian crossing and increase visibility for the pedestrian and driver. (ADA term)

curb ramp A combined ramp and landing to accomplish a change in level at a curb. This element provides
street and sidewalk access to pedestrians with mobility impairments. (ADA term)

 parallel curb ramp A curb ramp design where the sidewalk slopes down to a landing at
road level with the running slope of the ramp in line with the direction of sidewalk
travel
 perpendicular curb ramp A curb ramp design where the ramp path is perpendicular to
the curb and meets the gutter grade break at a right angle.

curb section A roadway cross section with curb and sidewalk.

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decision sight distance The distance needed for a driver to detect an unexpected or difficult-to-
perceive condition, recognize the condition, select an appropriate maneuver, and complete the
maneuver based on design conditions and design speed.

deflection (in respect to roundabouts) The change in the path of a vehicle imposed by the geometric
features of a roundabout resulting in a slowing of vehicles.

delineation Any method of defining the roadway operating area for the driver.

deliverable Any unique and verifiable product, result or capability to perform a service that must be
produced to complete a process, phase, or project.

Design Analysis A process and tool to record design element changes where the dimensions chosen do
not meet the value, or lie within the range of values, provided for that element in the Design Manual.
(see Chapters 300 and 1106).

Design Approval Documented approval of the design at this early milestone locks in design policy for
three years. Design approval becomes part of the Design Documentation Package (see Chapter 300.)

design-bid-build The project delivery method where design and construction are sequential steps in
the project development process (23 CFR 636.103).

design-build contract An agreement that provides for design and construction of improvements by a
consultant/contractor team. The term encompasses design-build-maintain, design-build-operate,
design-build-finance, and other contracts that include services in addition to design and construction.
Franchise and concession agreements are included in the term if they provide for the franchisee or
concessionaire to develop the project that is the subject of the agreement (23 CFR 636.103).

design-builder The firm, partnership, joint venture, or organization that contracts with WSDOT to
perform the work.

design controls Key parameters that critically shape design decisions and effect calculated dimensions
for some design elements. Design controls are conscientiously selected and work together with the
context characteristics to achieve a particular outcome (see Chapter 1103)

Design Clear Zone The minimum clear zone target value used in highway design.

Design Documentation Package (DDP) See Project File.

design element Any component or feature associated with roadway design that becomes part of the
final product. Examples include lane width, shoulder width, alignment, and clear zone (see Chapter
1105.)

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designer This term applies to WSDOT design personnel. Wherever “designer” appears in this manual,
design-build personnel shall deem it to mean: Engineer of Record, Design Quality Assurance Manager,
design-builder, or any other term used in the design-build contract to indicate design-build personnel
responsible for the design elements of a design-build project, depending on the context of information
being conveyed.

design hourly volume (DHV) Computed by taking the annual average daily traffic times the K-factor. It
can only be accurately determined in locations where there is a permanent traffic recording device
active 365 days of the year. It correlates to the peak hour (see peak hour), but it is not equivalent. In
some circumstances, it is necessary to use the peak hour data instead of DHV because peak hour can be
collected using portable traffic recorders.

design speed A design control; the speed used to determine the various geometric design features of
the roadway.

design up An approach to developing project alternatives utilizing the smallest dimensions that meet
the need by providing the desired performance.

design users A broad term intended to capture all modal users that currently utilize or are legally
permitted on a roadway segment or node.

design variance Same as Design Analysis.

design vehicle See intersection design vehicle.

design year The forecast year used for design as described in Chapter 1103. See also horizon year.

desirable Design criteria that are recommended for inclusion in the design.

detectable warning surface A tactile surface feature of truncated dome material built into or applied to
the walking surface to alert persons with visual impairments of vehicular ways. Federal yellow is the
color used on WSDOT projects to achieve visual contrast. Colors other than federal yellow that meet the
light-on-dark/dark-on-light requirement may be used on projects where cities have jurisdiction.
(Detectable warning surfaces are detailed in the Standard Plans.) (ADA term)

Determination of Nonsignificance (DNS) (SEPA) The written decision by the Regional Administrator
that a proposal will not have a significant impact and no EIS is required.

Determination of Significance (DS) (SEPA) A written decision by the Regional Administrator that a
proposal could have a significant adverse impact and an EIS is required.

directional design hour volume (DDHV) The traffic volume for the design hour in the peak direction of
flow, in vehicles per hour. For example, if during the design hour, 60% of the vehicles traveled
eastbound and 40% traveled westbound, then the DDHV for the eastbound direction would be the
DHV x 0.60.

divided multilane A roadway with two or more through lanes in each direction and a median that
physically or legally prohibits left turns, except at designated locations.

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document (verb) The act of including a short note to the Design Documentation Package that explains
a design decision.

dooring Describes a conflict with a parked vehicle door opening into a roadway bike facility.

driveway A vehicular access point that provides access to or from a public roadway.

easement A documented right, as a right of way, to use the property of another for designated
purposes.

element An architectural or mechanical component or design feature of a space, site, or public right of
way.

emergency escape ramp A roadway leaving the main roadway designed for the purpose of slowing
and stopping out-of-control vehicles away from the main traffic stream.

emergency vehicle signal A special adaptation of a conventional traffic signal installed to allow for the
safe movement of authorized emergency vehicles. Usually, this type of signal is installed on the highway
at the entrance into a fire station or other emergency facility. The signal ensures protected entrance
onto the highway for the emergency vehicle. When not providing for this movement, the signal either
operates continuously (consistent with the requirements for a conventional traffic signal) or displays
continuous green, which is allowed at non-intersection locations only. At least two identical displays are
required per approach.

enforcement observation point A place where a law enforcement officer may park and observe traffic.

entry angle The angle between the entry roadway and the circulating roadway measured at the yield
point (see Chapter 1320).

entry curve The curve of the left edge of the roadway that leads into the circulating roadway (see
Chapter 1320).

entry width The width of an entrance leg at the inscribed circle measured perpendicular to travel (see
Chapter 1320).

Environmental Assessment (EA) (NEPA) A document prepared for federally funded, permitted, or
licensed projects that are not categorical exclusions (CE), but do not appear to be of sufficient
magnitude to require an EIS. The EA provides enough analysis to determine whether an EIS or a FONSI
should be prepared.

Environmental Impact Statement (EIS) A detailed written statement of a proposed course of action,
project alternatives, and possible impacts of the proposal.

Environmental Review Summary (ERS) (see Project Summary) Part of the Project Summary document,
the ERS identifies environmental permits and approvals. It is prepared in the region and is required for
Design Approval.

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expressway A divided highway that has a minimum of two lanes in each direction for the exclusive use
of traffic and that may or may not have grade separations at intersections. A transportation context
characteristic that is designated for a divided highway with limited access that provides regional
mobility.

extrude A procedure for applying marking material to a surface by forcing the material through a die
to give it a certain shape.

facility All or any portion of buildings, structures, improvements, elements, and pedestrian or
vehicular routes located in a public right of way.

feature A component of a pedestrian access route, such as a curb ramp, driveway, crosswalk, or
sidewalk.

Federal Highway Administration (FHWA) The division of the U.S. Department of Transportation with
jurisdiction over the use of federal transportation funds for state highway and local road and street
improvements.

Federal Transit Administration (FTA) The division of the U.S. Department of Transportation with
jurisdiction over the use of federal funds for financial assistance to develop new transit systems and
improve, maintain, and operate existing systems.

final design Any design activities following preliminary design; expressly includes the preparation of
final construction plans and detailed specifications for the performance of construction work
(23 CFR 636.103). Final design is also defined by the fact that it occurs after NEPA/SEPA approval has
been obtained.

Finding of No Significant Impact (FONSI) (NEPA) A federal document indicating that a proposal will not
significantly affect the environment and an EIS is not required.

findings and order A document containing the findings and conclusions of a limited access hearing
approved by the Assistant Secretary, Engineering & Regional Operations (see Chapter 210).

findings and order plan A limited access plan, prepared after a limited access hearing, which is based
on the hearing record.

fixed feature (object to be mitigated) A fixed object, a side slope, or water that, when struck, can
result in impact forces on a vehicle’s occupants that may result in injury or place the occupants in a
situation that has a high likelihood of injury. A fixed feature can be either constructed or natural.

flangeway gap The gap for the train wheel at a railroad crossing. The space between the inner edge of
a rail and the pedestrian crossing surface. (ADA term)

flare The widening of the approach to the roundabout to increase capacity and facilitate natural
vehicle paths.

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flyer stop A transit stop inside the limited access boundaries.

footcandle (fc) The illumination of a surface one square foot in area on which a flux of one lumen is
uniformly distributed. One footcandle equals one lumen per square foot.

foreslope A sideslope that goes down as the distance increases from the roadway (fill slopes and ditch
inslopes).

freeway A divided highway that has a minimum of two lanes in each direction for the exclusive use of
traffic and with full control of access.

frontage road An auxiliary road that is a local road or street located beside a highway for service to
abutting property and adjacent areas and for control of access.

functional classification The grouping of streets and highways according to the character of the
service they are intended to provide.

geocomposites Prefabricated edge drains, wall drains, and sheet drains that typically consist of a
cuspated or dimpled polyethylene drainage core wrapped in a geotextile. The geotextile wrap keeps the
core clean so that water can freely flow through the drainage core, which acts as a conduit.
Prefabricated edge drains are used in place of shallow geotextile-wrapped trench drains at the edges of
the roadway to provide subgrade and base drainage. Wall drains and sheet drains are typically placed
between the back of the wall and the soil to drain the soil retained by the wall.

Geographic Information System (GIS) A computerized geographic information system used to store,
analyze, and map data. Data may be used with GIS if the data includes the Accumulated Route Mile
(ARM) or State Route Milepost (SRMP) programs. Global Positioning System (GPS) technology provides a
means of collecting data and is an alternative to ARM and SRMP. WSDOT’s primary desktop tool to view
and analyze GIS data is ArcGIS software. GIS is used to gather and analyze data to support the purpose
and need as described in the Project Summary
( http://wwwi.wsdot.wa.gov/gis/supportteam/default.asp).

geogrids A polymer grid mat constructed either of coated yarns or a punched and stretched polymer
sheet. Geogrids usually have high strength and stiffness and are used primarily for soil reinforcement.

geomembranes Impervious polymer sheets that are typically used to line ponds or landfills. In some
cases, geomembranes are placed over moisture-sensitive swelling clays to control moisture.

geonets Similar to geogrids, but typically lighter weight and weaker, with smaller mesh openings.
Geonets are used in light reinforcement applications or are combined with drainage geotextiles to form
a drainage structure.

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Glossary

geosynthetic erosion control The minimizing of surficial soil particle movement due to the flow of
water over the surface of bare soil or due to the disturbance of soil caused by construction activities
under or near bodies of water. This is the primary function of geotextiles used as silt fences or placed
beneath riprap or other stones on soil slopes. Silt fences keep eroded soil particles on the construction
site, whereas geotextiles placed beneath riprap or other stones on soil slopes prevent erosion from
taking place at all. In general, the permanent erosion control methods described in Chapter 630 are only
used where more natural means (like the use of biodegradable vegetation mats to establish vegetation
to prevent erosion) are not feasible. These functions control some of the geosynthetic properties, such
as apparent opening size (AOS) and permittivity, and in some cases load-strain characteristics. The
application will also affect the geosynthetic installation conditions. These installation conditions
influence the remaining geosynthetic properties needed, based on the survivability level required.

geosynthetic filtration The passage of water through the geosynthetic relatively unimpeded
(permeability or permittivity) without allowing passage of soil through the geosynthetic (retention). This
is the primary function of geotextiles in underground drainage applications.

geosynthetic survivability The ability of the geosynthetic to resist installation conditions without
significant damage, such that the geosynthetic can function as intended. Survivability affects the
strength properties of the geosynthetic required.

geotextiles (nonwoven) A sheet of continuous or staple fibers entangled randomly into a felt for
needle-punched nonwovens and pressed and melted together at the fiber contact points for heat-
bonded nonwovens. Nonwoven geotextiles tend to have low-to-medium strength and stiffness with high
elongation at failure and relatively good drainage characteristics. The high elongation characteristic
gives them superior ability to deform around stones and sticks.

geotextiles (woven) Slit polymer tapes, monofilament fibers, fibrillated yarns, or multifilament yarns
simply woven into a mat. Woven geotextiles generally have relatively high strength and stiffness and,
except for the monofilament wovens, relatively poor drainage characteristics.

gore The area downstream from the intersection of the shoulders of the main line and exit ramp.
Although generally referring to the area between a main line and an exit ramp, the term may also be
used to refer to the area between a main line and an entrance ramp.

gore nose At an exit ramp, the point at the end of the gore area where the paved shoulders of the
main line and the ramp separate (see Chapter 1360) or the beginning of traffic barrier, not including any
impact attenuator. Also, the similar point at an entrance ramp.

grade break The intersection of two adjacent surface planes of different grade. (ADA term)

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hearing An assembly to which the public is invited and at which participation is encouraged. Types of
hearings include:

 administrative appeal hearing A formal process whereby a property owner may appeal
WSDOT’s implementation of access management legislation. The appeal is heard by an
administrative law judge (ALJ), who renders a decision. (See Chapter 540 for administrative
appeal hearing procedures.)
 combined hearing A hearing held when there are public benefits to be gained by combining
environmental, corridor, design, and/or limited access subjects.
 corridor hearing A formal or informal hearing that presents the corridor alternatives to the
public for review and comment before a commitment is made to any one route or location.
This type of hearing is beneficial for existing corridors with multiple Improvement projects
programmed over a long duration.
 design hearing A formal or informal hearing that presents the design alternatives to the
public for review and comment before the selection of a preferred alternative.
 environmental hearing A formal or informal hearing documenting that social, economic, and
environmental impacts have been considered and that public opinion has been solicited.
 formal hearing format A hearing conducted by a moderator using a formal agenda, overseen
by a hearing examiner, and recorded by a court reporter, as required by law. Limited access
hearings require the use of the formal hearing format (see Chapter 210).
 informal hearing format A hearing where oral comments are recorded by a court reporter, as
required by law. An informal hearing often uses the “open house” format (see Chapter 210). A
formal agenda and participation by a hearing examiner are optional.
 limited access hearing A formal hearing that gives local public officials, owners of abutting
properties, and other interested persons an opportunity to be heard about the limitation of
access to the highway system.

hearing agenda An outline of the actual public hearing elements, used with formal hearings. (See
Chapter 210 for contents.)

Hearing Coordinator The HQ Access and Hearings Section Manager: (360) 705-7266.

hearing examiner An administrative law judge from the Office of Administrative Hearings, or a WSDOT
designee, appointed to moderate a hearing.

hearing script A written document of text to be presented orally by department representatives at a

hearing.

hearing summary Documentation prepared by the region and approved by Headquarters that
summarizes environmental, corridor, and design hearings. (See Chapter 210 for content requirements.)

hearing transcript A document prepared by the court reporter that transcribes verbatim all oral
statements made during the hearing, including public comments. This document becomes part of the
official hearing record.

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high-occupancy toll (HOT) lane A managed lane that combines a high-occupancy vehicle lane and a
toll lane.

high-occupancy vehicle (HOV) A vehicle that meets the occupancy requirements of the facility as
authorized by WAC 468-510-010.

high pavement type Portland cement concrete pavement or hot mix asphalt (HMA) pavement on a
treated base.

highway A general term denoting a street, road, or public way for the purpose of vehicular travel,
including the entire area within the right of way.

Highway Construction Program (HCP) A comprehensive multiyear program of highway Improvement

and Preservation projects selected by the Legislature.

Highway System Plan (HSP) A WSDOT planning document that addresses the state highway system
element of the Washington Transportation Plan (WTP). The HSP defines the service objectives, action
strategies, and costs to maintain, operate, preserve, and improve the state highway system for 20 years.
The HSP is the starting point for the state highway element of the CIPP and the state Highway
Construction Program. It is periodically updated to reflect completed work and changing transportation
needs, policies, and revenues. It compares highway needs to revenues, describes the “constrained”
costs of the highway programs, and provides details of conceptual solutions and performance in the
improvement program.

Highways of Statewide Significance (HSS) Include interstate highways and other principal arterials
that are needed to connect major communities in the state. The designation helps assist with the
allocation and direction of funding. (http://www.wsdot.wa.gov/planning/HSS)

Horizon year Typically considered to be 20 years from the year construction is scheduled to begin, as
described in Chapter 1103. See also design year.

HOV direct access ramp An on- or off-ramp exclusively for the use of HOVs that provides access
between a freeway HOV lane and a street, transit support facility, or another freeway HOV lane without
weaving across general-purpose lanes.

HOV facility A priority treatment for HOVs.

impact attenuator system A device that acts primarily to bring an errant vehicle to a stop at a
deceleration rate tolerable to the vehicle’s occupants or to redirect the vehicle away from a fixed
feature.

incorporated city or town A city or town operating under RCW 35 or 35A.

inscribed circle The outer edge of the circulating roadway.

inscribed circle diameter (ICD) The diameter of the inscribed circle (see Chapter 1320).

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inner corridor access a means of entering or leaving a roadside area inside of the state limited access
right of way without crossing over, under, or physically through the plane of limited access.

intelligent transportation systems (ITS) An integrated system of advanced sensor, computer,

electronics, and communication technologies and management strategies, used to increase the safety
and efficiency of the surface transportation system.

interchange A system of interconnecting roadways, in conjunction with one or more grade

separations, providing for the exchange of traffic between two or more intersecting highways or
roadways.

intermediate pavement type Hot mix asphalt pavement on an untreated base.

intersection An at-grade access point connecting a state highway with a road or street duly established
as a public road or public street by the local governmental entity.

intersection angle The angle between any two intersecting legs at the point the centerlines intersect.

intersection area The area of the intersecting roadways bounded by the edge of traveled ways and the
area of the adjacent roadways to the farthest point: (a) the end of the corner radii, (b) through any
marked crosswalks adjacent to the intersection, (c) to the stop bar, or (d) 10 feet from the edge of
shoulder of the intersecting roadway (see Chapter 1310).

Intersection, at grade The general area where a roadway or ramp terminal is met or crossed at a
common grade or elevation by another roadway.

 four-leg intersection An intersection formed by two crossing roadways.

 split tee A four-leg intersection with the crossroad intersecting the through roadway at two
tee intersections offset by at least the width of the roadway.
 tee (T) intersection An intersection formed by two roadways where one roadway terminates
at the point it meets a through roadway.
 wye (Y) intersection An intersection formed by three legs in the general form of a “Y” where
the angle between two legs is less than 60°.

intersection control beacon (also flashing beacon) A secondary control device, generally suspended
over the center of an intersection, that supplements intersection warning signs and stop signs. One
display per approach may be used; however, two displays per approach are desirable. Intersection
control beacons are installed only at intersections that control two or more directions of travel.

intersection leg Any one of the roadways radiating from and forming part of an intersection.

 entrance leg The lanes of an intersection leg for traffic entering the intersection.
 exit leg The lanes of an intersection leg for traffic leaving the intersection.
Note: Whether an intersection leg is an entrance leg or an exit leg depends on which movement is
being analyzed. For two-way roadways, each leg is an entrance leg for some movements and an exit
leg for other movements.

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intersection density The ratio of intersections per mile.

intersection design vehicle A specific selection of the vehicle to be used to dimension intersection
design elements at an individual intersection.

intersection sight distance The length of roadway visible to the driver of a vehicle entering an
intersection.

Interstate System A network of routes designated by the state and the Federal Highway
Administration (FHWA) under terms of the federal-aid acts as being the most important to the
development of a national system. The Interstate System is part of the principal arterial system.

island A defined area within an intersection, between traffic lanes, for the separation of vehicle
movements or for pedestrian refuge.

justify Preparing a memo to the DDP identifying the reasons for the decision: a comparison of
advantages and disadvantages of all options considered. A more rigorous effort than document.

K-factor The proportion of AADT occurring in the analysis hour is referred to as the K-factor, expressed
as a decimal fraction (commonly called “K,” “K30,” or “K100”). The K30 is the thirtieth (K100 is the one-
hundredth) highest peak hour divided by the annual average daily traffic. Normally, the K30 or K100 will
be in the range of 0.09 to 0.10 for urban and rural areas. Average design hour factors are available on
the web in the Transportation Data, GIS & Modeling Office’s Annual Peak Hour Report.

lamp lumens The total light output from a lamp, measured in lumens.

lane A strip of roadway used for a single line of vehicles.

lane control signal (reversible lanes) A special overhead signal that permits, prohibits, or warns of
impending prohibition of lane use.

lane width The lateral design width for a single lane, striped as shown in the Standard Plans and the
Standard Specifications. The width of an existing lane is measured from the edge of traveled way to the
center of the lane line or between the centers of adjacent lane lines.

landing A level paved area, within or at the top and bottom of a stair or ramp, designed to provide
turning and maneuvering space for wheelchair users and as a resting place for pedestrians. (ADA term)

lateral clearance The distance from the edge of traveled way to a roadside object.

layered networks Roadway network arrangement where the objective is to separate modes onto
different facilities with planned interconnection locations.

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lead agency The public agency that has the principal responsibility for carrying out or approving a
project.

left-cross Describes the intersection conflict between a motor vehicle left-turn and bicycle through
movement in the opposing direction.

legal road approach A road approach that complies with the requirements of Chapter 530 for limited
access facilities and Chapter 540 for managed access facilities.

length of need The length of a traffic barrier used to shield a fixed feature.

level of service (LOS) LOS is based on peak hour, except where noted. LOS assigns a rank (A – F) to
facility sections based on traffic flow concepts like density, delay, and/or corresponding safety
performance conditions. (See the Highway Capacity Manual and AASHTO’s Geometric Design of
Highways and Streets ["Green Book"] for further details.)

life cycle cost The total cost of a project or item over its useful life. This includes all of the relevant
costs that occur throughout the life of a project or item, including initial acquisition costs (such as right
of way, planning, design, and construction), operation, maintenance, modification, replacement,
demolition, financing, taxes, disposal, and salvage value as applicable.

light emitting diode (LED) A two-lead semiconductor light source.

limited access (L/A) Full, partial, or modified access control is planned and established for each
corridor and then acquired as the right to limit access to each individual parcel (see Chapter 520).

 acquired limited access control Access rights have been purchased.

 established limited access control An access hearing has been held and the Assistant
Secretary, Engineering & Regional Operations, has adopted the findings and order, which
establishes the limits and level of control.
 planned limited access control Limited access control is planned for some time in the future;
however, no access hearing has been held.

Limited Access and Managed Access Master Plan A map of Washington State that shows established
and planned limited access highways:  www.wsdot.wa.gov/design/accessandhearings

limited access highway All highways listed as “Established L/A” on the Limited Access and Managed
Access Master Plan and where the rights of direct access to or from abutting lands have been acquired
from the abutting landowners.

 full access control This most restrictive level of limited access provides access, using
interchanges, for selected public roads/streets only, and prohibits highway intersections at
grade.
 partial access control The second most restrictive level of limited access. At grade
intersections with selected public roads are allowed, and there may be some crossings and
some driveway approaches at grade. Direct commercial access is not allowed.

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 modified access control The least restrictive level of limited access. Characteristics are the
same as for partial access control except that direct commercial access is allowed.

local roads Non-state highways that are publicly owned.

long tunnel A tunnel, lid, or underpass that is greater than 80’ in length and has a length to vertical
clearance ratio greater than 10:1.

low pavement type Bituminous surface treatment (BST).

lumen The unit used to measure luminous flux.

luminaire A complete lighting unit comprised of a light bulb or light emitting Diode (LED) module,
wiring, and a housing unit.

luminance The quotient of the luminous flux at an element of the surface surrounding the point and
propagated in directions defined by an elementary cone containing the given direction, by the product
of the solid angle of the cone and area of the orthogonal projection of the element of the surface on a
plane perpendicular to the given direction. The luminous flux may be leaving, passing through, and/or
arriving at the surface.

luminous flux The time rate of the flow of light.

M2D2 Multimodal Development and Delivery

managed access highway Highways where the rights of direct access to or from abutting lands have
not been acquired from the abutting landowners.

managed lane A lane that increases efficiency by packaging various operational and design actions.
Lane management operations may be adjusted at any time to better match regional goals.

managing project delivery A WSDOT management process for project delivery from team initiation
through project closing.

maximum extent feasible (MEF) From the U.S. Department of Justice, 28 CFR Part 36.402, Alterations.
The phrase “to the maximum extent feasible” applies to “the occasional case where the nature of an
existing facility makes it virtually impossible to comply fully with applicable accessibility standards
through a planned alteration.” This phrase also refers to a stand-alone piece of design documentation
that WSDOT uses to record its reasons for not being able to achieve full ADA compliance in alteration
projects (called a Maximum Extent Feasible document). (ADA term)

maximum uniformity ratio The average light level within the design area divided by the minimum light
level within the design area (see Chapter 1040).

maximum veiling luminance ratio The maximum veiling luminance divided by the average luminance
over a given design area for an observer traveling parallel to the roadway centerline (see Chapter 1040).

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mcd/m2/lux Pavement marking retroreflectivity is represented by the coefficient of retroreflected

luminance (RL) measured in millicandelas per square meter.

Measures of Effectiveness (MOEs) In the context of Chapter 320, examples are: speed, delay, density,
LOS, QOS, person or vehicle throughput, cost vs. benefit, and queue. (See FHWA’s MOE List.)

median The portion of a divided highway separating vehicular traffic traveling in opposite directions.

median functions one or more reason(s) for a median as described in Chapter 1239.

median opening An opening in a continuous median for the specific purpose of allowing vehicle
movement.

Memorandum of Understanding (MOU) for a road approach permit There is a MOU (Highways Over
National Forest Lands) between the United States Forest Service (USFS) and WSDOT that requires the
USFS to obtain a road approach permit for new access to a state highway that is crossing Forest Service
land.

metering signal A signal used to control the predominant flow rate of traffic at an at-grade facility.

Methods and Assumptions Document A mandatory document developed at the beginning of the ARR
phase to record ARR assumptions, methodologies, criteria, and decisions (see Chapter 550).

Metropolitan Planning Organization (MPO) A lead agency designated by the Governor to administer
the federally required transportation planning process in a metropolitan area with a population over
50,000. The MPO is responsible for the 20 year long-range plan and Transportation Improvement
Program (TIP).

midblock pedestrian crossing A marked pedestrian crossing located between intersections. (ADA term)

minimum average light level The average of all light intensities within the design area, measured just
prior to relamping the system (see Chapter 1040).

minimum light level The minimum light intensity of illumination at any single point within the design
area measured just prior to relamping the system (see Chapter 1040).

minor arterial system A rural network of arterial routes linking cities and other activity centers that
generate long distance travel and, with appropriate extensions into and through urban areas, form an
integrated network providing interstate and interregional service (RCW 47.05.021).

minor operational enhancement projects These projects usually originate from the Q2 component of
the Q Program and are quick responses to implement low-cost improvements. They are typically narrow
in scope and focus on improvements to traffic operations and modifications to traffic control devices.
Guidance on the type of work included in the Q subprograms is in the Chart of Accounts.

modal compatibility An assessment to determine which mode(s) need to be considered strictly based
on the context characteristics present or planned. The assessment is independent of whether any

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particular mode is present on the segment, and intended to guide strategic investment opportunities on
a segment.

modal priority Mode(s) that will be prioritized when making design decisions for the project, guided by
the outcome of the modal compatibility assessment.

mode A specific type or form of transportation. Typically for roadway design the modes are:
automobiles, transit, truck freight, pedestrians, skateboards, and bicycles.

monument As defined in Chapter 410, a monument is any physical object or structure that marks or
references a survey point. This includes, but is not limited to, a point of curvature (P.C.), a point of
tangency (P.T.), a property corner, a section corner, a General Land Office (GLO) survey point, a Bureau
of Land Management (BLM) survey point, and any other permanent reference set by a governmental
agency or private surveyor.

monument removal or destruction The physical disturbance or covering of a monument such that the
survey point is no longer visible or readily accessible.

mounting height – luminaire The vertical distance between the surface of the design area and the
center of the light source of the luminaire. Note: This is not to be confused with pole height (H1), but is
the actual distance that the luminaire is located above the roadway edge line.

movable bridge signal (also drawbridge signal) A signal installed to notify traffic to stop when the
bridge is opened for waterborne traffic. Movable bridge signals display continuous green when the
roadway is open to vehicular traffic.

multimodal connection The point where multiple types of transportation activities occur; for example,
where transit buses and van pools drop off or pick up passengers (including passengers with bicycles).

National Highway System (NHS) The NHS was developed by the U.S. Department of Transportation
(DOT) in cooperation with the states, local officials, and metropolitan planning organizations (MPOs).
The NHS includes the following subsystems of roadways (note that a specific highway route may be on
more than one subsystem):

 Interstate The Eisenhower Interstate System of highways retains its separate identity within
the NHS.
 Other Principal Arterials These are highways in rural and urban areas that provide access
between an arterial and a major port, airport, public transportation facility, or other intermodal
transportation facility.
 Strategic Highway Network (STRAHNET) This is a network of highways that are important to
the United States' strategic defense policy and that provide defense access, continuity, and
emergency capabilities for defense purposes.
 Major Strategic Highway Network Connectors These are highways that provide access
between major military installations and highways that are part of the Strategic Highway
Network.

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 Intermodal Connectors These highways provide access between major intermodal facilities
and the other four subsystems making up the National Highway System.

natural vehicle path The natural path that a driver navigates a vehicle given the layout of the
intersection and the ultimate destination.

need A statement that identifies the transportation problem(s) or other performance gap

negative illumination Lighting the background and leaving the object dark to contrast with the light
behind it as the driver views it.

network connectivity How the various roadways and other transportation facilities within a network
interconnect in a defined geographic area.

nighttime The period of time from one-half hour after sunset to one-half hour before sunrise and any
other time when persons or objects may not be clearly discernible at a distance of 500 feet (RCW
46.04.200).

no-build condition The baseline, plus state transportation plan and comprehensive plan
improvements, expected to exist, as applied to the year of opening or the design year.

nonconforming road approach A road approach that does not meet current requirements for location,
quantity, spacing, sight distance, or geometric elements.

nonrecoverable slope A slope on which an errant vehicle might continue until it reaches the bottom,
without having the ability to recover control. Fill slopes steeper than 4H:1V, but not steeper than 3H:1V,
are considered nonrecoverable.

nonseparated HOV lane An HOV lane that is adjacent to and operates in the same direction as the
general-purpose lanes with unrestricted access between the HOV lane and the general-purpose lanes.

notice of appearance A form provided by WSDOT for anyone wanting to receive a copy of the findings
and order and the adopted limited access plan (see Chapter 210).

notice of hearing (or hearing notice) A published advertisement that a public hearing will be held.

notice of opportunity for a hearing An advertised offer to hold a public hearing.

occupancy designation The minimum number of occupants required for a vehicle to use the HOV
facility.

operating speed The speed at which drivers are observed operating their vehicles during free flow
conditions.

order of hearing The official establishment of a hearing date by the Director & State Design Engineer,
Development Division.

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outer separation The area between the outside edge of traveled way for through traffic and the
nearest edge of traveled way of a frontage road or collector-distributor (C-D) road.

overlapped displays Overlapped displays allow a traffic movement to operate with one or more
nonconflicting phases. Most commonly, a minor street’s exclusive right-turn phase is overlapped with
the nonconflicting major street’s left-turn phase. An overlapped display can be terminated after the
parent phase (the main phase the overlap is associated with) terminates. An overlapped display
programmed for two or more parent phases continues to display until all of the parent phases have
terminated. An overlap is made up of two or more phases—not one phase controlling two movements.

painted nose The point where the main line and ramp lanes separate.

passenger loading zone An area provided for pedestrians to board/disembark a vehicle. (ADA term)

passing lane An auxiliary lane on a two-lane highway used to provide the desired frequency of passing
zones.

passing sight distance The distance (on a two-lane highway) needed for a vehicle driver to execute a
normal passing maneuver based on design conditions and design speed.

pavement marking A colored marking applied to the pavement by spray, extrusion, adhesives, or glue
to provide drivers with guidance and other information.

pavement marking beads Glass: Small glass spheres used in highway pavement markings to provide
retroreflectivity. Composite: any non-glass bead intended to provide wet weather retroreflectivity.

pavement marking durability A measure of a pavement marking’s resistance to wear and

deterioration.

peak hour The 60-minute interval that contains the largest volume of traffic during a given time
period. If a traffic count covers consecutive days, the peak hour can be an average of the highest hour
across all of the days. An a.m. peak is simply the highest hour from the a.m., and the p.m. peak is the
highest from the p.m. The peak hour correlates to the DHV, but is not the same. However, it is close
enough on items such as intersection plans for approval to be considered equivalent.
pedestrian Any person afoot or using a wheelchair (manual or motorized) or means of conveyance
(other than a bicycle) propelled by human power, such as skates or a skateboard. (ADA term)
pedestrian access route (PAR) (synonymous with accessible route) A continuous, unobstructed
walkway within a pedestrian circulation path that provides accessibility. Pedestrian access routes consist
of one or more of the following pedestrian facilities: walkways/sidewalks, curb ramps (excluding flares),
landings, crosswalks, pedestrian overpasses/underpasses, access ramps, elevators, and platform lifts.
Note: Not all transportation facilities need to accommodate pedestrians. However, those that do
accommodate pedestrians need to have an accessible route. (ADA term)

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pedestrian circulation path A prepared exterior or interior way of passage provided for pedestrian
travel. Includes independent walkways, shared-use paths, sidewalks, and other types of pedestrian
facilities. All pedestrian circulation paths are required to contain a continuous pedestrian access route
that connects to all adjacent pedestrian facilities, elements, and spaces that are required to be
accessible. (ADA term)

pedestrian facilities Walkways such as sidewalks, walking and hiking trails, shared-use paths,
pedestrian grade separations, crosswalks, and other improvements provided for the benefit of
pedestrian travel. Pedestrian facilities are intended to be accessible routes. (ADA term)

pedestrian overpass or underpass A grade-separated pedestrian facility, typically a bridge or tunnel

structure over or under a major highway or railroad that allows pedestrians to cross. (ADA term)

pedestrian refuge island An island in the roadway that physically separates the directional flow of
traffic, provides pedestrians with a place of refuge, and reduces the crossing distance. Note: Islands with
cut-through paths are more accessible to persons with disabilities than are raised islands with curb
ramps. (ADA term)

pedestrian signal An adaptation of a conventional traffic signal installed at established pedestrian

crossings. It is used to provide a protected phase for pedestrians by terminating the conflicting vehicular
movements to allow for pedestrian crossings. (ADA term)

performance-based decisions Decisions that are made based on performance, performance metrics,
performance targets, and performance gaps. Also, decisions made using performance evaluation tools,
such as the Highway Safety Manual predictive methods for evaluating safety performance.
performance category Any broad area of performance important to an organization, project, or place.
WSDOT’s six performance categories: Economic Vitality, Preservation, Safety, Mobility, Environment,
and Stewardship are the result of legislative policy per RCW 47.04.280.
performance evaluation tools Quantitative tools used to measure performance. Examples of these
tools currently being used by WSDOT are Highway Safety Manual methodology (for safety performance)
and Highway Capacity Manual (for mobility performance).
performance gap The difference between the measured and targeted performance unit for a
performance metric. This gap is another way of describing the performance need(s) at a location.
performance metric Any measurable indicator used to assess the achievement of outcomes.
performance need See baseline performance need and contextual performance need
performance target(s) An outcome or desired state intended for a project. Performance targets are
identified as either baseline or contextual (see Chapter 1101).
permit holder The abutting property owner or other legally authorized person to whom an access
connection permit is issued by the permitting authority.
permitted access connection A connection for which an access connection permit has been issued by a
permitting authority.

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permitting authority The agency that has legal authority to issue managed access connection permits.
For access connections in unincorporated areas, the permitting authority is WSDOT; for access
connections within corporate limits, the permitting authority is a city or town.

person with a disability Per the U.S. Department of Justice: An individual with a disability is defined by
the ADA as a person who has a physical or mental impairment that substantially limits one or more
major life activities, a person who has a history or record of such an impairment, or a person who is
perceived by others as having such an impairment. It is defined by law through the American with
Disabilities Act. (ADA term)

physical nose The point, upstream of the gore, with a separation between the roadways of 16 to 22
feet (see Chapter 1360).
planning Transportation planning is a decision-making process required by federal and state law used
to solve complex, interrelated transportation and land use problems.
Planning and Environmental Linkage (PEL) A collaborative and integrated approach to transportation
decision-making that (1) considers environmental, community, and economic goals early in the planning
process, and (2) uses the information, analysis, and products developed during planning to inform the
environmental review process.
Plans, Specifications, and Estimates (PS&E) The project development activity that follows Project
Definition and culminates in the completion of contract-ready documents and the engineer’s cost
estimate.
pole height (H1) The vertical distance from the light source to the pole base. This distance is specified
in contracts and used by the pole manufacturers to fabricate the light standard.

portable traffic signal A type of conventional traffic signal used in work zones to control traffic. This
signal is most commonly used on two-way two-lane highways where one lane has been closed for
roadwork. This signal is most commonly operated in pairs, with one signal at each end of the work zone.
This eliminates the need for 24-hour flagger control. The traffic signal provides alternating right of way
assignments for conflicting traffic movements. The signal has an adjustable vertical support with two
three-section signal displays and is mounted on a mobile trailer with its own power source.

positive illumination Lighting the surface of the object as the driver views it.

posted speed The maximum legal speed as posted on a section of highway using regulatory signs.

Practical Design/Practical Solutions An approach to making project decisions that focuses on the
specific problem the project is intended to address. This performance-based approach looks for lower
cost solutions that meet outcomes that WSDOT, partnering agencies, communities and stakeholders
have identified. Practical design is a fundamental component to the vision, mission, values, goals, and
reforms identified in Results WSDOT- WSDOT’s Strategic Plan. With practical solutions, decision-making
focuses on maximum benefit to the system, rather than maximum benefit to the project. Focusing on
the specific project need minimizes the scope of work for each project so that system-wide needs can be
optimized.

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prehearing packet A concise, organized collection of all necessary prehearing data, prepared by the
region and approved by the HQ Access and Hearings Section Manager prior to the hearing (see Chapter
210).

preliminary engineering (PE) A term used to describe the Project Delivery process from project
scoping through PS&E review.

principal arterial system A connected network of rural arterial routes with appropriate extensions into
and through urban areas, including routes designated as part of the Interstate System, that serves
corridor movements with travel characteristics indicative of substantial statewide and interstate travel
(RCW 47.05.021).

Priority Programming Process The rational selection of projects and services according to factual need
and an evaluation of life cycle costs and benefits.

project The Project Management Institute defines a project to be "a temporary endeavor undertaken
to create a unique product or service."

Project Definition (see Project Summary)

Project Development Approval Final approval of all project development documents by the
designated representative of the approving organization prior to the advertisement of a capital
transportation project (see Chapter 300).

Project Engineer This term applies to WSDOT personnel. Wherever “Project Engineer” appears in this
manual, the design-builder shall deem it to mean “Engineer of Record.”

Project File (PF) A file containing all documentation and data for all activities related to a project (see
Chapter 300).
 Design Documentation Package (DDP) The portion of the Project File, including Design
Approval and Project Development Approval that will be retained long term in accordance with
WSDOT document retention policies. Depending on the scope of the project, it contains the
Project Summary and some or all of the other documents discussed in Chapter 300. Technical
reports and calculations are part of the Project File, but they are not designated as components
of the DDP. Include estimates and justifications for decisions made in the DDP (see Chapter
300). The DDP explains how and why the design was chosen and documents approvals.

project management plan A formal, approved document that defines how the project is executed,
monitored, and controlled. It may be in summary or detailed form and may be composed of one or
more subsidiary management plans and other work planning documents. For further information, see
the Project Management Guide:
http://www.wsdot.wa.gov/Projects/ProjectMgmt/OnlineGuide/ProjectManagementOnlineGuide.htm

project need statement A statement identifying the baseline performance need for the project. For
each identified project need, there may be one or more performance metrics, targets, and gaps.

Project Scoping See scoping phase.

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Project Summary A set of documents consisting of the, Environmental Review Summary (ERS), and
Project Definition (PD). The Project Summary is part of the design documentation required to obtain
Design Approval and is ultimately part of the design documentation required for Project Development
Approval (see Chapter 300).

 Environmental Review Summary (ERS) A document that records the environmental

classification (class of action) and considerations (consequences of action) for a specific project.
 Project Definition (PD) A document that records the purpose and need of the project, along
with program level and design constraints.

Projects of Division Interest (PoDIs) A primary set of projects for which FHWA determines the need to
exercise oversight and approval authority, as described in Chapter 300.

proposal The combination of projects/actions selected through the study process to meet a specific
transportation system need.

public art An enhancement to a functional element, feature, or place within a transportation facility to
provide visual interest. The enhancement could be an addition to a functional element, integrated into a
design, or for purely aesthetic purposes. An element is considered “public art” if it is beyond WSDOT
standard practice for architectural treatment.

public involvement plan A plan to collaboratively involve the public in decision making, tailored to the
specific needs and conditions of a project and the people and communities it serves. It is often part of a
broader communications plan.

public transportation Passenger transportation services available to the public, including buses,
ferries, rideshare, and rail transit.

purpose General project goals such as improve safety, enhance mobility, or enhance economic
development.

Quality of Service (QOS) Defined by the Highway Capacity Manual or by agreement. Intended to
describe how well a facility or service operates or functions from the perspective of the user.

quantitative safety analysis An analysis of quantitative safety performance based on data-driven

science based tools and techniques that model modal crash potential.

quantitative tools Analytical tools used to measure performance. Examples of tools currently being
used by WSDOT are:
 Highway Safety Manual predictive methods (for safety performance)
AASHTOWare SafetyAnalyst
ISATe (spreadsheet tool for implementing the HSM predictive methods for
freeways and interchanges)
IHSDM (FHWA software tool for implementing the HSM predictive methods)

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HSM Enhanced Spread Sheets (spreadsheet tools for implementing the HSM
predictive methods for rural two lane two way roadways, rural multilane roads,
and urban and suburban arterials)
See also http://wwwi.wsdot.wa.gov/highwaysafety
 Highway Capacity Manual (for mobility performance)

queue cutter traffic signal A traffic signal used at highway-rail grade crossings where the queue from a
downstream traffic signal is expected to extend within the Minimum Track Clearance Distance. It is used
to keep vehicles from an adjacent signalized intersection from queuing on the railroad tracks.

raised median A raised island in the center of a road used to restrict vehicle left turns and side street
access. Note: Islands with cut-through paths are more accessible to persons with disabilities than are
raised islands with curb ramps. (ADA term)

ramp A walking surface with a running slope steeper than 20H:1V (5%). (ADA term)

ramp (in relation to a Roadway) A short roadway connecting a main lane of a highway with another
facility, such as a road, parking lot, or transit stop, for vehicular use.

ramp connection The pavement at the end of a ramp, connecting to a main lane of a roadway.

ramp meter A traffic signal at a freeway entrance ramp that allows a measured or regulated amount of
traffic to enter the freeway.

ramp terminal An intersection at the end of a ramp.

Record of Decision (ROD) Under the National Environmental Policy Act, the Record of Decision
accompanies the Final Environmental Impact Statement; explains the reasons for the project decision;
discusses alternatives and values considered in selection of the preferred alternative; and summarizes
mitigation measures and commitments that will be incorporated in the project.

recoverable slope A slope on which the driver of an errant vehicle can regain control of the vehicle.
Slopes of 4H:1V or flatter are considered recoverable.

recovery area The minimum target value used in highway design when a fill slope between 4H:1V and
3H:1V starts within the Design Clear Zone.

Recreational Vehicle Account In 1980 the RV account was established for use by the department of
transportation for the construction, maintenance, and operation of recreational vehicle sanitary disposal
systems at safety rest areas (RCW 46.68.170). A recreational vehicle sanitary disposal fee is required for
registration of a recreational vehicle (RCW 46.17.375). Adjustments to the recreational vehicle fee by
the department of transportation may be implemented after consultation with the citizens’
representatives of the recreational vehicle user community (RCW 47.01.460).

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Regional Transportation Planning Organization (RTPO) A planning organization authorized by the

Legislature in 1990 as part of the Growth Management Act. The RTPO is a voluntary organization with
representatives from state and local governments that are responsible for coordinating transportation
planning activities within a region.

relocation assistance program A program that establishes uniform procedures for relocation
assistance that will ensure legal entitlements and provide fair, equitable, and consistent treatment to
persons displaced by WSDOT-administered projects, as defined in the Right of Way Manual.

Request for Proposal (RFP) The document package issued by WSDOT requesting submittal of
proposals for the project and providing information relevant to the preparation and submittal of
proposals, including the instructions to proposers, contract documents, bidding procedures, and
reference documents.

rest area An area to the side of a path.

résumé An official notification of action taken by WSDOT following adoption of a findings and order
(see Chapter 210).

retroreflection The phenomenon of light rays striking a surface and being returned directly back to the
source of light.

Retroreflection, coefficient of (RL) A measure of retroreflection.

retroreflectometer An instrument used to measure retroreflectivity.

right-hook Potential intersection conflicts between motor vehicles making a right turn and the bicycle
through movement.

right of way (R/W) A general term denoting land or interest therein, acquired for or designated for
transportation purposes. More specifically, lands that have been dedicated for public transportation
purposes or land in which WSDOT, a county, or a municipality owns the fee simple title, has an
easement devoted to or required for use as a public road/street and appurtenant facilities, or has
established ownership by prescriptive right.

right of way and limited access plan (R/W and L/A plan) A right of way plan that also shows limited
access control details.

road approach An access point, other than a public road/street, that allows access to or from a limited
access highway on the state highway system.

roadside park A roadside user facility for safe vehicular parking off the traveled way and separated
from the highway by some form of buffer. These sites might be equipped with features or elements such
as points of interest, picnic tables, and/or vault toilet buildings. Unlike a safety rest area, a roadside park
does not always provide a permanent restroom building.

roadway The portion of a highway, including shoulders.

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roadway luminance The light projected from a luminaire that travels toward a given area, represented
by a point on the pavement surface, and then back toward the observer, opposite to the direction of
travel. The units of roadway luminance are footcandles.

roundabout A circular intersection at grade with yield control of all entering traffic, channelized
approaches with raised splitter islands, counter-clockwise circulation, and appropriate geometric
curvature to force travel speeds on the circulating roadway generally to less than 25 mph.

rumble strips Rumble strips are grooves or rows of raised pavement markers placed perpendicular to
the direction of travel, or ground in a continuous longitudinal sinusoidal pattern. They are used to alert
inattentive drivers.

running slope A slope measured in the direction of travel, normally expressed as a percent. (ADA term)

Safety Analyst A program developed to implement the Highway Safety Manual methodology

safety rest area (SRA) A roadside facility equipped with permanent restroom building(s), a parking
area, picnic tables, refuse receptacles, illumination, and other ancillary services. SRAs typically include
potable water and might include traveler information and telephones.

Safety Rest Area Strategic Plan Developed in 2008 under a stakeholder-coordinated effort of
executive and advisory team members, this plan provides guidance for current and future management
of the SRA program.

sawtooth berth A series of bays that are offset from one another by connecting curb lines, constructed
at an angle from the bus bays. This configuration minimizes the amount of space needed for vehicle pull
in and pull out.

scoping phase An initial phase of project development for a specific project. The scoping phase
precedes the design and/or preliminary engineering phase and is intended to support priority
programing and budget building scenarios. The Project Summary is the documentation developed during
this phase.

security lighting A minimal amount of lighting used to illuminate areas for public safety or theft
reduction. Security lighting for walkways is the lighting of areas where shadows and horizontal and
vertical geometry obstruct a pedestrian’s view.

separated HOV facility An HOV roadway that is physically separated from adjacent general-purpose
lanes by a barrier or median, or is on a separate right of way.

shared-use landing A level (0 to 2% grade cross slope and running slope) paved area within the
shared-use path, designed to provide turning and maneuvering space for wheelchair users and as a
resting place for pedestrians.

shared-use path A facility physically separated from motorized vehicular traffic within the highway
right of way or on an exclusive right of way with minimal crossflow by motor vehicles. Shared-use paths

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are primarily used by bicyclists and pedestrians, including joggers, skaters, and pedestrians with
disabilities, including those who use nonmotorized or motorized wheeled mobility devices. With
appropriate design considerations, equestrians may also be accommodated by a shared-use path
facility.

short tunnel A tunnel, lid, or underpass that is shorter than 80’ in length and has a length to vertical
clearance ratio of 10:1 or less.

shoulder The portion of the roadway contiguous with the traveled way, primarily for accommodation
of stopped vehicles, emergency use, lateral support of the traveled way, and where allowed, use by
pedestrians and bicycles.

shoulder width The lateral dimension of the shoulder, measured from the edge of traveled way to the
edge of roadway or the face of curb.

sidewalk A walkway along a highway, road, or street intended for use by pedestrians. (ADA term)

sight distance The length of highway visible to a driver.

SIgnal Maintenance Management System (SIMMS) A database used for traffic signals, illumination,
and Intelligent Transportation Systems (ITS). SIMMS is used to establish an inventory base, enter work
reports, print timesheets, and store maintenance records for electrical/electronic systems within
WSDOT right of way.

single-lane roundabout A roundabout having single-lane entries at all legs and one circulating lane.

single-occupant vehicle (SOV) Any motor vehicle other than a motorcycle carrying one occupant.

site Parcel(s) of land bounded by a property line or a designated portion of a public right of way. (ADA
term)

site design Style and configuration of the built environment or parcel(s).

slip base A mechanical base designed to allow the light standard to break away from the fixed
foundation when hit by a vehicle traveling at the design speed and traveling at a departure angle less
than or equal to the design departure angle.

slip lane A lane that separates heavy right-turn movements from the roundabout circulating traffic
(see Chapter 1320).

slip ramp A connection between legs of an intersection that allows right-turning vehicles to bypass the
intersection or a connection between an expressway and a parallel frontage road. These are often
separated by an island.

slow-moving vehicle turnout A shoulder area widened to provide room for a slow-moving vehicle to
pull out of the through traffic, allow vehicles to pass, and then return to the through lane.

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speed The operations or target or posted speed of a roadway. There are three classifications of speed
established:
 Low speed is considered 35 mph and below.
 Intermediate speed is considered 40-45 mph.
 High speed is considered 50 mph and above.

speed limit sign beacon A beacon installed with a fixed or variable speed limit sign. The preferred
display is two flashing yellow indications.

speed management An engineered effort to achieve a targeted speed.

speed transition segment An engineered segment of road intended to lower the operating speed
between contexts with different target speeds.

splitter island The raised island at each two-way leg between entering and exiting vehicles, designed
primarily to control the entry and exit speeds by providing deflection. They also discourage wrong-way
movements, and provide pedestrian refuge.

state highway system All roads, streets, and highways designated as state routes in compliance with
RCW 47.17.

static scale A scale that requires a vehicle to stop for weighing.

stopping sight distance The distance needed for a driver to stop a vehicle traveling at design speed
based on design conditions.

stop sign beacon A beacon installed above a stop sign. The display is a flashing red indication.

street furniture Sidewalk equipment or furnishings, including garbage cans, benches, parking meters,
and telephone booths. (ADA term)

streetside The portion of the public right of way dedicated to the pedestrian thoroughfare and
supporting the accessibility, activities and functions of the local land use. The streetside is comprised of
a frontage zone, pedestrian zone and furnishing zone (see Chapter 1238). Note some local agencies may
divide the streetside zone.

study area The transportation system area to study in the study process and for an ARR. The study
area is a minimum of one interchange upstream and downstream from the proposal. The study area
shall also include the intersecting roadway in the area to the extent necessary to ensure its ability to
collect and distribute traffic to and from the interchange. The study area should be expanded as
necessary to capture operational impacts of adjacent interchanges in the vicinity that are, or will be,
bottlenecks or chokepoints that influence the operations of the study interchange.

study plan A term associated with environmental procedures, this plan proposes an outline or “road
map” of the environmental process to be followed during the development of a project that requires
complex NEPA documentation (see Chapter 210 and the Environmental Manual).

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subject matter expert A person who is an authority in a particular area or topic, and understands the
data and the limitations on the use and application of the data.

superelevation The rotation of the roadway cross section in such a manner as to overcome part of the
centrifugal force that acts on a vehicle traversing a curve.

superelevation runoff The length of highway needed to accomplish the change in cross slope from a
section with adverse crown removed (level) to a fully superelevated section, or vice versa.

superelevation transition length The length of highway needed to change the cross slope from normal
crown or normal pavement slope to full superelevation.

support team An integral part of the ARR process consisting of an assemblage of people from the
regions, FHWA (for Interstates), WSDOT HQ Access and Hearings, and other representatives organized
to develop and analyze alternatives to meet the need of a proposal, including approval authorities.

Surface Transportation Program (STP) A federal program established by Congress in 1991 that
provides a source of federal funding for highway and bridge projects.

tangent runout The length of highway needed to change the cross slope from normal crown to a
section with adverse crown removed (level).

target speed A proactive approach to establishing a speed consistent with the context characteristics.
Target speed is the design operating speed, which aligns design, posted and operating speed as the
same value.

temporary traffic signal A conventional traffic signal used during construction to control traffic at an
intersection while a permanent signal system is being constructed. A temporary traffic signal is typically
an inexpensive span-wire installation using timber strain poles.

tradeoffs analysis An analysis method for balancing factors, performance or outcomes, which are not
attainable at the same time.

traffic barrier A longitudinal barrier, including bridge rail or an impact attenuator, used to redirect
vehicles from fixed features located within an established Design Clear Zone, help mitigate median
crossovers, reduce the potential for errant vehicles to travel over the side of a bridge structure, or
(occasionally) protect workers, pedestrians, or bicyclists from vehicular traffic.

traffic barrier/longitudinal barrier A device oriented parallel or nearly parallel to the roadway whose
primary function is to contain or safely redirect errant vehicles away from fixed features or to
(occasionally) protect workers, pedestrians, or bicyclists from vehicular traffic. Beam guardrail, cable
barrier, bridge rail, concrete barrier, and impact attenuators are barriers, and they are categorized as
rigid, rigid anchored, unrestrained rigid, semirigid, and flexible. They can be installed as roadside or
median barriers.

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traffic calming Design techniques that have been shown to reduce traffic speeds and unsafe
maneuvers. These techniques can be stand-alone or used in combination, and they include lane
narrowing, curb extensions, surface variations, and visual clues in the vertical plane. (ADA term)

traffic calming treatments Treatments along the roadway that can be used to reduce speeds through
a section of roadway (see Chapter 1103).

Traffic Impact Analysis (TIA) (sometimes called Traffic Impact Study (TIS)) If a traffic analysis is not an
ARR it is a TIA. TIAs are used for environmental reviews and developer projects (see Chapter 320).

transit A general term applied to passenger rail and bus service used by the public.

transit facility A capital facility that improves the efficiency of public transportation or encourages the
use of public transportation.

transit flyer stop A multimodal connection located within the boundaries of a limited access facility.

transition A section of barrier used to produce the gradual stiffening of a flexible or semirigid barrier
as it connects to a more rigid barrier or fixed object.

transitional segments Segments of a pedestrian circulation path that blend between existing
undisturbed pedestrian facilities and newly altered pedestrian facilities. Use of transitional segments
may permit the work of the alteration to more nearly meet the new construction standards. At a later
time, when other segments of the pedestrian circulation path are altered, the noncomplying transitional
segments can be removed and replaced with pedestrian facilities that meet the accessibility criteria.
(ADA term)

transit lane A lane for the exclusive use of transit vehicles.

transit stop A facility for loading and unloading passengers that is set aside for the use of transit
vehicles only.

transit vehicle A bus or other motor vehicle that provides public transportation (usually operated by a
public agency).

Transportation Management Area (TMA) Urbanized areas with populations of 200,000 or greater are
federally designated as Transportation Management Areas.

transportation management plan (TMP) A set of traffic control plans, transportation operations plans,
and public information strategies for managing the work zone impacts of a project. A TMP is required for
all projects to address work zone safety and mobility impacts.

travel demand The demand travelers will make on the system based on the number and types of trips
they will take and the mode and routes they will use. Local travel demand represents short trips that
should be made on the local transportation system, such as intracity roads and streets. Regional travel
demand represents long trips that are made on the regional transportation system, such as Interstate,
regional, and/or intercity/interregional roads, streets, or highways.

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traveled way The portion of the roadway intended for the movement of vehicles, exclusive of
shoulders and lanes for parking, turning, and storage for turning.

traveled way zone The portion of the roadway intended for the movement of people and goods,
exclusive of shoulders, roadsides, on-street parking, medians and streetside zones.

traveler information Commercial and noncommercial information that informs and orients the
traveling public. This includes access information for food, gas, lodging, local attractions, regional tourist
attractions, roadway conditions, and construction schedules.

traveling public Motorists, motorcyclists, bicyclists, pedestrians, and pedestrians with disabilities.

trips Short trips are normally local. Long trips are normally interstate, regional, or interregional.

truck apron The optional mountable portion of the central island of a roundabout between the raised
nontraversable area of the central island and the circulating roadway (see Chapter 1320).

turning radius The radius that the front wheel of the intersection design vehicle on the outside of the
curve travels while making a turn (see Chapter 1320).

turning roadway A curve on an open highway, a ramp, or the connecting portion of the roadway
between two intersecting legs of an intersection.

two-way left-turn lane (TWLTL) A lane, located between opposing lanes of traffic, to be used by
vehicles making left turns from either direction, from or onto the roadway.

undivided multilane A roadway with two or more through lanes in each direction on which left turns
are not controlled.

uniformity ratio The ratio of the minimum average light level on the design area to the minimum light
level of the same area (see Chapter 1040).

universal access Access for all persons regardless of ability or stature. (ADA term)

urban area An area designated by the Washington State Department of Transportation (WSDOT) in
cooperation with the Transportation Improvement Board (TIB) and Regional Transportation Planning
Organizations (RTPO), subject to the approval of the Federal Highway Administration (FHWA).

urbanized area An urban area with a population of 50,000 or more.

usable shoulder The width of the shoulder that can be used by a vehicle for stopping.

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validation A process to confirm the reasonableness, accuracy and completeness of estimated costs
and quantities.

Value Engineering (VE) Analysis A systematic approach to identifying and removing unnecessary costs
which do not contribute to a desired result by analyzing cost versus function.

Value Engineering Change Proposal (VECP) A construction contract change proposal submitted by the
construction contractor based on a VECP provision in the contract. The intent of these types of
proposals is to (1) improve the project's performance, value, and/or quality, (2) lower construction
costs, or (3) shorten the delivery time, while considering their impacts on the project's overall life-cycle
cost and other applicable factors.

Value Engineering (VE) Job Plan A systematic and structured action plan (see Chapter 310) for
conducting and documenting the results of the VE analysis. While each VE analysis shall address each
phase in the VE Job Plan, the level of analysis conducted and effort expended for each phase should be
scaled to meet the needs of each individual project. The WSDOT VE analysis uses the Seven-Phase Job
Plan shown in Exhibit 310-1.

veiling luminance The stray light produced within the eye by light sources produces a veiling
luminance that is superimposed on the retinal image of the objects being observed. This stray light
alters the apparent brightness of an object within the visual field and the background against which it is
viewed, thereby impairing the ability of the driver to perform visual tasks. Conceptually, veiling
luminance is the light that travels directly from the luminaire to the observer’s eye.

viewpoint A roadside stopping opportunity with a view of some point of interest or area scenery. This
area is not typically separated from the traveled way by some form of highway buffer.

violation rate The total number of violators divided by the total number of vehicles on an HOV facility.

visioning exercises a process of determining the goals for a facility or place.

Visitor Information Center (VIC) A staffed or nonstaffed booth or separate building that displays and
dispenses free tourist travel maps and brochures. These are typically located at border-entry SRAs to
provide travel information to highway users as they enter the state.

walk interval That phase of a traffic signal cycle during which the pedestrian is to begin crossing,
typically indicated by a WALK message or the walking person symbol and its audible equivalent. (ADA
term)

walkway The continuous portion of the pedestrian access route that is connected to street crossings
by curb ramps. (ADA term)

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warning beacon A beacon that supplements a warning or regulatory sign or marking. The display is a
flashing yellow indication. These beacons are not used with STOP, YIELD, or DO NOT ENTER signs or at
intersections that control two or more lanes of travel. A warning identification beacon is energized only
during those times when the warning or regulation is in effect.

warrant A minimum condition for which an action is authorized. Meeting a warrant does not attest to
the existence of a condition that needs attention. Further justification is required.

Washington Transportation Plan (WTP) A WSDOT planning document developed in coordination with
local governments, regional agencies, and private transportation providers. The WTP addresses the
future of transportation facilities owned and operated by the state as well as those the state does not
own but in which it has an interest. It identifies needed transportation investments, which are defined
by service objectives and specific desired outcomes for each transportation mode.

weaving section A length of highway over which one-way traffic streams cross by merging and
diverging maneuvers.

weigh in motion (WIM) A scale facility capable of weighing a vehicle without the vehicle stopping.

wet film thickness Thickness of a pavement marking at the time of application without beads.

work zone An area of a highway with construction, maintenance, or utility work activities. A work zone
is identified by the placement of temporary traffic control devices that may include signs, channelizing
devices, barriers, pavement markings, and/or work vehicles with warning lights. It extends from the first
warning sign or high-intensity rotating, flashing, oscillating, or strobe lights on a vehicle to the END
ROAD WORK sign or the last temporary traffic control device (MUTCD).

work zone impact Highway construction, maintenance, or utility work operations in the traveled way,
adjacent to the traveled way, or within the highway’s right of way that creates safety and mobility
concerns for workers or the traveling public.

work zone traffic control The planning, design, and preparation of contract documents for the
modification of traffic patterns due to work zone impacts.

wye (Y) connection An intersecting one-way roadway, intersecting at an angle less than 60°, in the
general form of a “Y.”

yield-at-entry The requirement that vehicles on all entry lanes yield to vehicles within the circulating
roadway.

yield point The point at which entering traffic must yield to circulating traffic before entering the
circulating roadway (see Chapter 1320).

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