TRAFFIC CONTROL DEVICE

Lecture Outline
1. Components and Objectives
2. General Requirements
3. Traffic Signs
4. Latest Trend In Signs
5. Sign Problems in Bangladesh

Ref:
Manual of Uniform Traffic Control Devices
(MUTCD) + BRTA

2
 TRAFFIC CONTROL DEVICES

Traffic control device include all

» Signs
» Markings
» Signals

Objective
– To regulate
– To warn
– To guide traffic movements
– To ensure safe and smooth flow of traffic
movements
 General Requirements:

Traffic control devices should:

➢ Fulfill a need- must be reasonable and appropriate for the

traffic requirements at the locations used
➢ Command attention & respect of drivers & pedestrians
➢ Convey a clear and simple meaning-legible at long range and
understandable at a glance.
➢ Give users time for proper response
➢ Be uniform in design and application-the size, shape, color of
the device/letter/Symbol, mounting height, and lighting should
be uniform and consistent
➢ Be visible both at day and night
 General Requirements (cont..)

Traffic control devices should:

Be maintained at high standard - to ensure legibility and
visibility
Generally as some control devices impose restriction on
vehicle movements — it is recommended that –

o These should be used conservatively to avoid

disrespect by the drivers — if used in excess, tend to
lose their effectiveness.

o Moreover, these should not be used alone, where

enforcement is required to compel drivers to obey
them.
How These Requirements are Met?

Design
Placement
Uniformity
Operation (for electronic signs)
Maintenance
 Traffic Signs
Traffic signs are mainly used to
•inform drivers about regulation
•adjust their lane position and speed.
•guide them to reach their point of interest.
Classification
Traffic Sign

Warning Mandatory Informative

Spl
Regulatory Prohibitory
Mandatory
Mandatory Signs: (shall follow)
• Inform users about traffic laws & regulations.
• Violation is a legal offence.
• Usually circular in shape with red border, white background

Types:
1. Regulatory 2. Prohibitory 3.Special Mandatory Signs
Regulatory Signs are traffic signs intended to instruct road users on
what they must or should do under a given set of circumstances.
They give users notice of traffic laws and regulations.
Example: Slow, Keep Right/left, One way traffic etc.
Prohibitory Traffic Signs :

• Prohibitory traffic signs are used to prohibit certain

types of maneuvers or some types of traffic.

• Examples: No right/left/U turn, No entry, No horn,

No parking etc.

• Shape: Most mandatory road signs are Circular

having white symbols on a blue background with
white border or having black symbols on a white
background with a red border, although the latter is
also associated with prohibitory signs.
Prohibitory Signs
Prohibitory Signs
Special Mandatory Signs
 Special Mandatory Signs- YIELD
In road transport, a yield (Canada, Ireland, and the United
States) or give way (many Commonwealth countries)
traffic sign indicates that a driver of a vehicle must slow
down and prepare to stop if necessary (usually while
merging into traffic on another road) but does not need to
stop if there is no reason to.

Used when vision is not obstructed and stop is needed

only when necessary

Shape: Equilateral triangular pointing downward, with

white border and white symbol, red letters
 Special Mandatory Signs- Stop Sign

A stop sign is a traffic sign, usually employed at road

junctions, that instructs drivers to stop and then to
proceed only if the way ahead is clear.

Used when vision is obstructed.

In the United States and Canada they are commonly

used in residential areas, and near places where
children play, as a general safety measure.

SHAPE: Octagonal, red background with white border

and white symbol/letters
Warning or Cautionary Signs: (should
follow)
• Convey message to warn or to direct attention
to condition on or adjacent to a street that pose
potential hazards to traffic operations (Safety
Sign)
• Violation is not always an offence.
• Examples: Junctions, Side road, Narrow bridge,
School, Hospital, Sharp bend, level X,
zigzag/slippery road etc.
• Shape: In most countries, they usually take the
shape of an equilateral triangle or diamond. with
a white background and a thick red border.
Warning or Cautionary Signs: (Example)
Informatory or Guide Signs: (may
follow)

• An information sign informs people the direction

of important places of interest
• Guide the road users to make the travel
convenient, safe and comfortable.
• Used in a location where motorists would be in
doubt.
• Don’t loose effectiveness by over-use.
• Examples: Route direction, milestone / distance
etc.
• Shape: Usually rectangular.
Informatory or Guide Signs
 Sign Dimensions
Placement:
Left side of the road
Open/rural area: not more than 2 m away
Built up area: not more than 0.5 m
For multilane HW: overhead sign
Height:
Open area: 1.5 m
Built up area: 2.0 m

Size of Letterings: Should be such that they can be easily read

when vehs are moving.
USA: Type of HW
UK: Empirical formula related to traffic speed
 Sign Support
• Unless properly designed, unshielded traffic
signs may invite hazard.

• A tremendous amount of impact force creates

when out-of-control vehicles collide/strike with
the rigid signposts/supports.

• As such breakaway/collapsible sign support is

recommended - to absorb impact energy instead
of to react (with this arrangement when a
vehicle strike the post, it rotate about the
hinged joint and clear the vehicle as it passes).
Breakable/Collapsible Sign-posts
Sign Vandalism and Options

1.Perforated sign support.

2.Effective road marking which is
cost-effective
Reflective Post Panels
 New Trend
• Increasing use of icons, logos and symbols
instead of using letters and words.
• Increasing use of breakable/collapsible /shock
absorbing typed sign-posts especially when
they are placed near to the carriageway
• Increasing use of Variable Message Signs
(VMS)
 VMS

A variable- (also changeable) message sign, is an electronic traffic

sign often used on roadways to give travelers information about
special events.

Conventional signs are very rigid but VMS displays real time
information,

They are more responsive to field condition.

They need electricity and data communication network.

 VMS
The information is most often displayed in real-time and can be
controlled either from a remote centralized location or locally at
the site.

Traveler information displayed on VMS may be generated as a

result of a planned or unplanned event, which is programmed
or scheduled by operations personnel.

Examples of traveler information include: Travel times between

known destinations, Congestion conditions along a freeway
corridor, Construction notices, Special event notice and
motorist instructions, Maintenance operations schedule,
Pending severe weather announcement, Incident notification
VMS
VMS
VMS
VMS
 Chevron Arrows
• Signs indicating a sharp bend on a road.
• Chevron shaped arrows on rectangular signs may
be placed at the actual location of the bend or
curve to further mark the location of the curve
and to assist in negotiation of the curve.
Sign Problems in
Bangladesh
Sign problems in Bangladesh
-Absence of complete “Highway Manual”.
-Faulty designs (inconsistent size, color,
wording, incorrect height, placement etc.).
-Absence of required signs at potentially
hazardous locations.
-Misuse of signs.
-Obstructed signs.
-Poor maintenance.
Sign problems in Bangladesh (cont..)

@ Existence of misguiding signs.

@ Lack of supplementary markings.
@ Presence of a large number of illiterate road users.
# Eventually all these factors contributed to drop the
respect & effectiveness of traffic signs as controlling
device and in consequence, with time a tendency has
developed among the road users to ignore the signs.
# As power failure is very common, use of retro- reflective
signs/markings would be most appropriate even within the
city areas.
Example Video
Any Question