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1. Traffic operation/management
Dr Rawid
Shoaib.M

2. Books
• Transportation Engineering Introduction to
Planning, Design and Operations, by Jason C,
Yui, Elsevier, Latest Edition.
• Introduction to Transportation Engineering, by
James H Bank, McGraw Hill.
• Traffic Engineering by MC Shane, Rogers P. Roess,
Elena. S. Prassas.
• Traffic Engineering and Design, by Salter R. J.,
McGraw Hill, Latest Edition.

3. Traffic control devices
• Control, regulate and guide the traffic.
• Get free flow of traffic without un-necessary
interruption and congestion.
• Minimize road accident by regulating the
traffic
• Protect pedestrians from accidents
• Provide general safety and efficiency to the
road way
(TCD)

4. TCD on roads
• Traffic control devices made by paints (white,
yellow), may be lines, words, patterns or
symbols on the pavement, kerb, side of the
island or on fixed objects near the road way
• Convey simple and clear meaning
• Give adequate time for proper response

5. Requirements of control devices
• The most common traffic control devices are:
• Road marking and islands
• Traffic signs
• Traffic signals

6. Type of road marking
• Pavement marking
• Kerb marking
• Object marking
• Pavement marking: Centreline (used in two lane
highways to separate the opposite flow)
• Lane line: To separate lanes of multilane highway
• Non passing zone: they indicate that overtaking is
not permitted here
• Pavement edge lane: To show the edge of the
pavement

7. TCD
• Turn marking: to take turn at intersections
• Stop lines: transverse line to stop or zebra
crossing
• Zebra crossing: transverse lines at intersection
for pedestrians
• Channelizing lines: To channelize the traffic on
proper line
• Parking space limits: shows that parking
facility is available

8. TCD
• Kerb marking: visibility, lane/turning direction
• Object marking: strips are painted on
bridge/flyover support, traffic island, signal
poles etc to indicate the visibility.

9. Traffic island
• Raised area constructed in right of way mostly
at intersection to channelize the vehicle in the
desired direction/ route. It may be
• Divisional island
• Channelized island
• Roundabout
• Refuge (for pedestrian to wait for traffic to
stop)

10. Traffic island

11. Traffic signs
• Traffic signs are mounted on a support to
warn, direct or guide the road user. The sign is
fixed at a distance/location such that it is
clearly visible from a distance so that driver
can percept on time.
• Colour and shape of sign explains the message
• Types: Regularity, warning and informatory
• Regularity: It indicate a definite regulation
that has to be fallowed by all the vehicles
followed

12. Traffic signs

13. TCD
• Regularity may be (1) mandatory: A definite
positive instruction, (2) Prohibitry: A definite
negative instruction, Keep left/ right, Weight
limit, Reduce speed
• Warning sign: gives information about a hazard
that may be present on or close to road. steep
slope, turn left/ right, U turn, rough road
• Information signs: provides information about
destination, facilities etc. Islamabad 140km, rest
area 3km, parking signs are also informatory

14. Design of traffic signs
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15. Traffic signs
• V is the design speed,
• A driver can read a 1 inch high letter from a
distance of 50 feet
• It takes (N/3+2) sec to read a sign consists of
N number of words.
• Shape of sign board: Circular (regularity),
triangular (warning), square(informatory)
• (In US the warning signs are of diamond
shape)

16. Traffic signals
• A traffic signal is advice which is normally
electrically or mechanically operated so that
traffic alternatively directed to stop and
permitted. It consist of: a signal head and control
mechanism
• control mechanism may be:
• Local control mechanism
• Central control mechanism
• Cycle time : time required to control one
sequence (green-amber-red)

17. Benefits of signals
• Increase capacity,
• Reduce accident,
• Provide continuous movement,
• Economical
• Readable under fogy / dark condition
• Interruption of heavy traffic for crossing
• Impartial
• Types of signals: (1) continuous off-on and (2)
sequence (green-amber-red)

18. Signal controller
• Automatic controlled signals: where the traffic is
supervised with the help of predetermined cycle
time (pre-timed signals), it is good for constant
traffic intensity, may cause delay during peak
hours
• Traffic actuated signals:, where the cycles time
varies according to the traffic demand and it
received signals from traffic detectors and thus
adjust the cycle time. May be fully or semi
actuated

19. TCD
• Location of signals: (1) over head, (2) pole on
road side.
• Flexible progressive system: The signals are so
coordinated that a vehicle which is allowed to
proceed the first intersection gets a green
light at every one of the subsequent
intersection. Traffic actuated signals may be
used in flexible progressive system.

20. Channelization
• Layout design of road sections for specifying
vehicular paths is considered as channelization
• Purpose of channelization: It reduce area of
conflict, diverting traffic to a specific lane.
• Types/examples of channelization: turn at
intersection, a lane ahead closed due to accident,
road maintenance etc.
• For channelization during night, extra lighting is
provided to increase visibility (red/amber colour
light is good for visibility)

21. Channelization

22. Channelization

23. Speed studies
• Rate of change of distance or distance/time,
expressed as mile/hr, km/hr etc
• It is used for :
• Geometric design: Horizontal and vertical
curves, vertical gradient, Superelevation, Sight
distance
• Traffic control devices: traffic sign location,
timing of signals

24. Speed studies
• Accident location: Effective mass and traffic
control
• Travel time and delay study: identification of
problem location, measurement of level of
service, input to economic analysis
• Spot speed: it is the instantaneous speed of a
vehicle as it passes on a specified point for
example at intersection, bridge etc.

25. Speed studies
• Spot speed study is used for:
• To study speed trend
• Traffic capacity
• Planning traffic control measures such as signals,
signs, island etc
• Re-designing/improvement of existing highway
• Studying causes of accidents
• Studying driver behaviours (old, middle age and
young drivers)

26. Speed studies
• Time mean speed & space mean speed:
• Running speed: average speed maintained by
vehicle over a certain section of route.
• Running speed=(length of journey)/(time of
journey-delays at signals, crossing, intersections
etc)
• Design speed: The maximum safe speed that can
be maintained over a specific section of highway
when the conditions are so favourable that the
design features of the highway govern

27. Speed studies
• Factors affecting speed/spot speed:
• Drivers/road users (single, long or short journey)
• Type/condition of vehicles
• Road way (gradient, curves, width etc)
• Traffic volume
• Time (slight difference during day and night time)
• Environment (fog, raining, snow etc)

28. Speed studies
• Measurement of spot speed:
• By time and distance (using tape and stop
watch , using mirror box (it is not a suitable
one))
• Pneumatic tube method
• Using Doppler's effect (radar, ultrasonic)
• Time laps photography