Transportation Engineering- II

Lecture 1

By
Engr. Muhammad Waseem
Lecturer Department of Civil Engineering
UET, Jalozai Campus

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 Course Outline
 Introduction to Road Systems: Location Survey in Rural and Urban Areas; Urban
Location Controls; Highway Planning. Roads in Hilly Areas

 Highway Engineering: Highway Components, Elements of a typical cross-section of

road. Types of cross-section; Highway location; Classification of Highways; Highway
Materials, Types & Characteristics, Specifications & tests, Introduction to resilient
behavior

 Geometric Design: Design controls and criteria; Sight distance requirements; Horizontal
curves; Super elevation; Transition curve; Curve widening; Grade line; Vertical curves

 Pavement Design: Types of pavements. Wheel loads. Equivalent single axle load,
Repetition and impact factors. Load distribution characteristics; Design of flexible and
rigid pavements, Highway drainage, Pavement failures, Introduction to non-destructive
testing, Pavement evaluation; Construction, Maintenance and rehabilitation

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 Tests, Exams & Graded Marks
 Mid Term Exam = 20 marks

 Final Term Exam = 60 marks

 Quizzes = 10 marks

 CEP = 10 marks

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 Recommended Books
 Traffic and Highway Engineering 4th Edition by Nicholas J.
Garber, Lester A. Hoel

 Introduction to Transportation Engineering 2nd Edition by James

H. Banks

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 Transportation Engineering
 Transportation engineering or transport engineering is the
application of technology and scientific principles to the planning,
functional design, construction, operation and management of
facilities for any mode of transportation in order to provide for the
safe, efficient, rapid, comfortable, convenient, economical, and
environmentally compatible movement of people and goods

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 Highway Engineering
 Highway engineering is an engineering discipline that involves the
planning, design, construction, operation, and maintenance of
roads, bridges, and tunnels to ensure safe and effective
transportation of people and goods.

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 Functional Classification of Roads
 Functional classification is the process by which streets and
highways are grouped into classes, or systems, according to the
character of traffic service that they are intended to provide.

 The classification based on speed and accessibility is the most

generic one

 As the accessibility of road increases, the speed reduces

 Accordingly, the roads can be classified in the order of increased

accessibility and reduced speeds.

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Mobility and Accessibility

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 Functional Classification of Roads
 Freeways: A freeway may be defined as a divided highway with full
control of access and two or more lanes for the exclusive use of traffic in
each direction and are designed for high speeds. Most freeways are four
lanes, two lanes each direction, but many freeways widen to incorporate
more lanes as they enter urban areas. Access is controlled through the
use of interchanges
 Expressways: They are superior type of highways and are designed for
high speeds (120 km/hr is common), high traffic volume and safety.
They are generally provided with grade separations at intersections.
Parking, loading and unloading of goods and pedestrian traffic is not
allowed on expressways

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 Functional Classification of Roads
 Highways: They represent the superior type of roads in the country. Highways
are of two types – rural highways and urban highways. Rural highways are
those passing through rural areas (villages) and urban highways are those
passing through large cities and towns, ie. urban areas. Highways are designed
for speeds less than freeways and expressways (less mobility, 80km/hr.) and
with partially controlled access.
 Arterials: It is a general term denoting a street primarily meant for through
traffic usually on a continuous route. They are generally divided highways with
partially controlled access and speed of about 70km/hr. Parking, loading and
unloading activities are usually restricted and regulated. Pedestrians are allowed
to cross only at intersections/designated pedestrian crossings.

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 Functional Classification of Roads
 Collector streets: These are streets intended for collecting and
distributing traffic to and from local streets and also for providing access
to arterial streets. Normally full access is provided on these streets.
There are few parking restrictions except during peak hours. They are
designed for speeds of 50km/hr.

 Local streets: A local street is the one which is primarily intended for
access to residence, business or abutting property. It does not normally
carry large volume of traffic and also it allows unrestricted parking and
pedestrian movements. Local streets are designed for speeds with
30km/hr. - 40km/hr.
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Functional Classification of Roads

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 Highway Alignment
 Highway location involves the acquisition of data concerning the terrain
upon which the road will traverse and the economical siting of an alignment
 Important factors needing consideration: earthwork, geologic conditions, and
land use
 Geometric design principles are used to establish the horizontal and vertical
alignment, including consideration of the driver, the vehicle, and roadway
characteristics
 Design of parking and terminal facilities must be considered as they form an
integral part of the total system
 Since the new highway will alter existing patterns of surface and subsurface
flow, thus careful attention to the design of drainage facilities is required

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 Highway Alignment
 Roadway elements such as curvature and grade must blend with
each other to produce a system that provides for the easy flow of
traffic at the design capacity, while meeting design criteria and
safety standards

 The highway should cause a minimal disruption to historic and

archeological sites and to other land-use activities

 Environmental impact studies are therefore required in most cases

before a highway location is finally agreed upon

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 Highway Alignment
 The position or lay out of centerline of the highway on the ground is called the
alignment.
 It includes straight path, horizontal deviation and curves.
 Due to improper alignment ,the disadvantages are,
 Increase in construction
 Increase in maintenance cost
 Increase in vehicle operation cost
 Increase in accident cost
 Once the road is aligned and constructed, it is not easy to change the alignment
due to increase in cost of adjoining land and construction of costly structure.

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Highway Alignment

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Highway Alignment

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Highway Alignment

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 Requirements of Highway Alignment
 Short
 Easy
 Safe
 Economical
 Short: Desirable to have a short alignment between two terminal stations.
 Easy: Easy to construct and maintain the road with minimum problem also easy for
operation of vehicle.
 Safe: Safe enough for construction and maintenance from the view point of stability
of natural hill slope, embankment and cut slope also safe for traffic operation.
 Economical: Total cost including initial cost, maintenance cost and vehicle
operation cost should be minimum

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Factors Controlling Highway Alignment
 Factors Controlling Alignment
 Obligatory points
 Traffic
 Geometric design
 Economics
 Other considerations
 Additional Care in Hill Roads
 Stability
 Drainage
 Geometric standards of hill roads

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Factors Controlling Highway Alignment
 Obligatory Points
Obligatory points through which alignment is to pass
 Examples:-bridge site, intermediate town etc.…
Obligatory points through which alignment should not pass.
 Examples:-religious places, costly structure, unsuitable land etc.…
 Traffic
• Origin and destination survey should be carried out in the area and
the desire lines be drawn showing the trend of traffic flow.
• New road to be aligned should keep in view the desired lines, traffic
flow patterns and future trends.
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Factors Controlling Highway Alignment
 Geometric Design
Design factors such as gradient, radius of curve and sight
distance also govern the final alignment of the highway.
Gradient should be flat and less than the ruling gradient or
design gradient.
Avoid sudden changes in sight distance, especially near
crossings
Avoid sharp horizontal curves
Avoid road intersections near bend

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Factors Controlling Highway Alignment
 Economy

 Alignment finalized based on total cost including initial cost,

maintenance cost and vehicle operation cost.

 Other Consideration

 Drainage consideration

 Political consideration

 Surface water level, high flood level

 Environmental consideration

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Factors Controlling Highway Alignment
 Topographical Control Points (Controlling factors in Hilly Areas)
 The alignment, where possible should avoid passing through :
 Marshy (water logged) and low lying land with poor drainage
 Flood prone areas
 Unstable hilly features
 Materials and Constructional Features
Deep cutting should be avoided
Earth work is to be balanced; quantities for filling and excavation
Alignment should preferably be through better soil area to minimize pavement
thickness
Location may be near sources of embankment and pavement materials

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Factors Controlling Highway Alignment
 Stability
 A common problem in hilly roads is land sliding
 The cutting and filling of the earth to construct the roads on hilly sides
causes steepening of existing slope and affect its stability.
 Drainage
 Avoid the cross drainage structure
 The number of cross drainage structure should be minimum.
 Geometric Standard of Hilly Road
 Gradient, curve and speed
 Sight distance, radius of curve

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 Phases of Highway Location Process
 Office study of existing information

 Reconnaissance survey

 Preliminary location survey

 Final location survey

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 Office study of existing information
 Data Examination (office study) - The first phase in any highway location
study is the examination of all available data of the area in which the road is
to be constructed
 This phase is usually carried out prior to any field or photogrammetric
investigation.
 Data Sources: (National/Provincial departments - transportation, agriculture,
geology, hydrology, and mining)
 Existing engineering reports
 Maps
 Aerial photographs
 Charts

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 Office study of existing information
 The type and amount of data collected and examined depend on the type
of highway being considered
 Area characteristics covered in data collection:
 Engineering, including topography, geology, climate, and traffic
volumes
 Social and demographic, including land use and zoning patterns
 Environmental, including types of wildlife; location of recreational,
historic, and archeological sites; and the possible effects of air, noise,
and water pollution
 Economic, including unit costs for construction and the trend of
agricultural, commercial, and industrial activities
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 Office study of existing information
 Preliminary analysis of the data
 Will indicate whether any of the specific sites should be excluded from
further consideration because of one or more of the above
characteristics
 For example, if it is found that a site of historic and archeological
importance is located within an area being considered for possible
route location, it may be immediately decided that any route that
traverses that site should be excluded from further consideration.
 At the completion of this phase of the study, the engineer will be able
to select general areas through which the highway can traverse.

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 Reconnaissance Survey
 The object of this phase of the study is to identify several feasible routes,
each within a band of a limited width of a few hundred feet
 Rural roads - there is often little information available on maps or photographs,
and therefore aerial photography is widely used to obtain the required
information.
 Feasible routes are identified by a stereoscopic examination of the aerial
photographs, taking into consideration factors such as:
 Terrain and soil conditions
 Serviceability of route to industrial and population areas
 Crossing of other transportation facilities, such as rivers, railroads, and
highways
 Directness of route
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 Reconnaissance Survey
 Control points between the two endpoints are determined for
each feasible route

 For example, a unique bridge site with no alternative may be taken

as a primary control point

 The feasible routes identified are then plotted on photographic

base maps

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 Preliminary Location Survey
 During this phase of the study, the positions of the feasible routes
are set as closely as possible by:

1) Establishing all the control points

2) Determining preliminary vertical and horizontal alignments for each

 Preliminary alignments are used to evaluate the economic and

environmental feasibility of the alternative routes

 Economic Evaluation: Economic evaluation of each alternative route is

carried out to determine the future effect of investing the resources
necessary to construct the highway

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 Preliminary Location Survey
 Factors considered in economic evaluation
 Road user costs
 Construction costs
 Maintenance costs
 Road user benefits
 Road user dis-benefits - such as adverse impacts due to dislocation of families,
businesses, and so forth.
 Results of economic evaluation of the feasible routes:
 Provide information on the economic resources that will be gained or lost if a
particular location is selected
 Aid the policy maker in determining whether the highway should be built, and if
so, what type of highway it should be

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 Preliminary Location Survey
 Environmental Evaluation
 Highway construction at any location - significant impact on surroundings
 A highway - an integral part of the local environment
 Environment includes plant, animal, and human communities and encompasses
social, physical, natural, and man-made variables
 These variables are interrelated in a manner that maintains equilibrium and sustains
the lifestyle of the different communities
 The construction of a highway at a given location may result in significant
changes in one or more variables, which in turn may offset the equilibrium and
result in significant adverse effects on the environment.
 This may lead to a reduction of the quality of life of the animals and/or human
communities.
 Essential to evaluate environmental impact of alignment selected

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 Preliminary Location Survey
 In cases environmental impact study (EIS) is required, it is conducted at this stage to
determine the environmental impact of each alternative route

 EIS will determine the negative and/or positive effects the highway facility will have
on the environment

 Example:

 At grade freeway construction, urban area - may result in an unacceptable noise level for
the residents (negative impact)

 Highway facility may be located so that it provides better access to jobs and recreation
centers (positive impact)

 Public hearings are also held at this stage - provide an opportunity for constituents to give
their views point

 Best alternative, based on all the factors considered, is then selected as the preliminary
alignment of the highway.
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 Final Location Survey
 The final location survey is a detailed layout of the selected route

 The horizontal and vertical alignments are determined, and the

positions of structures and drainage channels are located

 The method used is to set out the points of intersections of the straight
portions of the highway and fit a suitable horizontal curve between these

 Best alignment is obtained using a trial-and-error process (designer’s

opinion) considering both engineering and aesthetic factors

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 Highway Earthwork and Final Plan
 The final element in the location process - to establish the
horizontal and vertical alignments of the highway project and to
prepare highway plans and specifications for estimating project
costs and preparation of bids by contractors

 Terrain significantly influences the cost to transport earthen

materials that will be used to construct the roadbed

 The final result of the location process is a highway plan used in

estimating quantities and computing the overall project cost

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 Highway Grades and Terrain
 One factor that significantly influences the selection of a highway location is
the terrain of the land, which in turn affects the laying of the grade line

 The primary factor that the designer considers on laying the grade line is the
amount of earthwork that will be necessary for the selected grade line

 One method to reduce the amount of earthwork is to set the grade line as
closely as possible to the natural ground level

 This is not always possible, especially in undulating or hilly terrain

 The least overall cost also may be obtained if the grade line is set such that
there is a balance between the excavated volume and the volume of
embankment

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 Highway Grades and Terrain
 Another factor that should be considered in laying the grade line is the existence
of fixed points, such as railway crossings, intersections with other highways,
and in some cases existing bridges, which require that the grade be set to meet
them.
 When the route traverses flat or swampy areas, the grade line must be set high
enough above the water level to facilitate proper drainage and to provide
adequate cover to the natural soil
 The height of the grade line is usually dictated by the expected floodwater level
 Grade lines should also be set such that the minimum sight distance
requirements are obtained
 Highway grade should be established that minimizes earth moving and
maximizes the use of native soil

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Final Location Survey

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Final Location Survey

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 Highway Location in Urban Areas
 Additional factors that significantly influence the location of
highways in urban areas include:

i. Connection to local streets

ii. Right-of-way acquisition

iii. Coordination of the highway system with other transportation

systems

iv. Adequate provisions for pedestrians

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 Highway Location in Urban Areas
 Connection to local streets

 Which local streets should connect with on- and off ramps to the
expressway or freeway?

 The main factor to consider is the existing travel pattern in the area

 The location should enhance the flow of traffic on the local streets

 The location should provide for adequate sight distances at all ramps

 Ramps should not be placed at intervals that will cause confusion or

increase the crash potential on the freeway or expressway.

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 Highway Location in Urban Areas
 Right-of-way acquisition
 Cost of acquiring right of way - significant affect on the location of highways in
urban areas
 Cost is largely dependent on the predominant land use in the right of way of the
proposed highway
 Costs much higher in commercial areas What if there in no
right of way available?
 Elevated structures in urban areas
 No acquisition of rights of way
 Minimum disruption of commercial and residential activities
 Minimal interference with existing land-use activities
 Noise or for aesthetic
 Very expensive to construct - problem of high costs not eliminated completely

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Highway Location in Urban Areas

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Highway Location in Urban Areas

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Highway Location in Urban Areas

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Highway Location in Urban Areas

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 Highway Location in Urban Areas
 Coordination of the Highway System with Other Transportation Systems
 Urban planners strive toward providing a fully integrated system of highways
and public transportation
 Integration should be taken into account during the location process of an urban
highway
 Main objective is to provide new facilities that will increase the overall level of
service of the transportation system in the urban area.
 Example: Park-and-ride facilities provided at transit stations to facilitate the use
of the Metro system
 Multiple use of rights of way – (transportation system integration)
 bus or rail facilities are constructed either in the median or alongside the
freeway
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 Highway Location in Urban Areas
 Adequate Provisions for Bicycles and Pedestrians
 Pedestrians are an integral part of any highway system but are more
numerous in urban areas than in rural areas
 Bicycles are an alternate mode of transportation that can help to reduce energy
use and traffic congestion
 Pedestrians facilities - include sidewalks, crosswalks, traffic-control features,
curb cuts, and ramps for the handicapped
 Facilities for bicycles - wide-curb lanes, bicycle paths and shared-use paths
 In heavily congested urban areas, the need for grade-separated facilities, such
as overhead bridges and/or tunnels, may have a significant effect on the final
location of the highway

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 Highway Survey Methods
 Highway surveys - involve measuring and computing horizontal and
vertical angles, vertical heights (elevations), and horizontal distances

 Surveys are used to prepare base maps with contour lines (that is, lines
on a map connecting points that have the same elevation) and
longitudinal cross-sections.

 Surveying techniques can be grouped into three general categories:

 Ground surveys

 Remote sensing

 Computer graphics

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 Highway Survey Methods
 Ground Surveys
 Ground surveys are the basic location technique for highways
 The total station is used for measuring angles in both vertical and horizontal planes,
distances, and changes in elevation through the use of trigonometric levels
 Level is used for measuring changes in elevation only
 Major survey equipment
 The Total Station
 Electronic Distance-Measuring Devices (EDM)
 Theodolite
 Levels
 Measuring Tapes
 Survey Data Collectors
 Global Positioning System Surveys

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 Highway Survey Methods
 Remote sensing
 Remote sensing is the measurement of distances and elevations by using
devices located above the earth, such as airplanes or orbiting satellites
using GPS
 The most commonly used remote-sensing method is photogrammetry,
which utilizes aerial photography
 Photogrammetry is the science of obtaining accurate and reliable
information through measurements and interpretation of photographs,
displaying this information in digital form and/or map form
 Fast and economical process for large projects but can be very expensive
for small projects
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 Highway Survey Methods
 Remote sensing
 The successful use of the method depends on the type of terrain. Difficulties will
arise when it is used for terrain with the following characteristics
 Areas of thick forest, such as tropical rain forests, that completely cover the
ground surface
 Areas that contain deep canyons or tall buildings, which may conceal the
ground surface on the photographs
 Areas that photograph as uniform shades, such as plains and some deserts
 Common uses of photogrammetry in highway engineering :
 Identification of suitable locations for highways corridor study
 Preparation of base maps for design mapping, showing all physical and man-
made features plus contours of 2- or 5-ft intervals

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Grand Canyon National Park - USA

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