Traffic regulation: - traffic signs types of traffic signs ,regulatory , mandatory, warning signs route marker, lane marking, lane widthstandards as IRC . Necessity of traffic signals criteria for providing traffic signals types of traffic signals. Methods of designing traffic signals.

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PREPARED BY : ASST. PROF. VATSAL D. PATEL
MAHATMA GANDHI INSTITUTE OF
TECHNICAL EDUCATION &
RESEARCH CENTRE, NAVSARI.

2.  The various aids and devices used to control, regulate and
guide traffic are :
1. Signs
2. Signals
3. Marking
4. Islands
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3.  The function of traffic sign are :
1. They give timely warning of hazardous situations, when
they are not evident.
2. Traffic signs are helpful in regulating traffic by imparting
messages to the drivers about the need to stop, give way, speed
limit, etc.
3.They give information about highway routes, directions and
points of interest.
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4.  Various traffic signs have been recognized by the government
of India through motor vehicle act, 1939.
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TRAFFIC SIGNS
REGULATORY SIGNS
(Mandatory Signs &
Prohibitory Signs)
WARNING SIGNS
(Cautionary signs)
INFORMATORY SIGNS
(Indication, Direction,
Route Identification)

5.  Regulatory or mandatory signs are meant to inform the road
user of certain laws, regulations and prohibitions. The
violation of these signs is a legal offence.
 All mandatory or regulatory signs are circular in shape. They
are with red circular ring and diagonal bars with white/black
symbols or arrows or letters on white/blue background.
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6.  The regulatory signs are classified under the following sub-
heads :
 Stop and give-way sign
 Prohibitory signs
 No Parking sign and No stopping signs
 Speed limit and vehicle control signs
 Restriction end signs
 Compulsory direction control signs
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STOP GIVE WAY

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NO ENTRY ONE WAY

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VEHICLES
PROHIBITED IN
BOTH DIRECTIONS
LEFT/RIGHT TURN
PROHIBITED

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U-TERN PROHIBITED OVERTAKING PROHIBITED

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NO PARKING NO STOPPING

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PEDESTRIAN PROHIBITED HORN PROHIBITED

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SPEED LIMIT LOAD LIMIT

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HEIGHT LIMIT WIDTH LIMIT

15.  Warning or cautionary signs are used to warn the road user of
certain hazardous conditions that exists on or adjacent to the
roadway.
 The warning signs are in the shape of a equilateral triangle
with its apex pointing upwards. They have a white
background, red border and black symbols.
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16.  The side of triangle is 45 cm.
 The triangular plate is fixed to the vertical post with its lower
side 2.75 m above the ground level.
 About 15 cm below the triangular plate an explanatory plate of
size 45 cm X 40 cm is fixed.
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RIGHT HAND CURVE LEFT HAND CURVE

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HAIRPIN BEND

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PEDESTRIAN CROSSING NARROW BRIDGE

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SLIPPERY ROAD MAN AT WORK

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STEEP ASCENT GAP IN MEDIAN

22.  These signs are used to guide the road user along routes,
inform them of destination and distance and provide with
information to make travel easier, safe and pleasant.
 Information signs are rectangular in shape and are also used
with destination names and distances with arrows indicating
the direction.
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23.  These signs are placed at distance 0.6 m from the kerb and at
2.0 to 3.0 m from the edge of carriage way in case of roads
without kerb.
 Various informatory signs are :
1. Direction and place identification signs
2. Facility information signs
3. Parking signs
4. Flood gauge
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ADVANCE DIRECTION DIRECTION

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REASSURANCE PLACE IDENTIFICATION

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PUBLIC TELEPHONE HOSPITAL

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PETROL PUMP FIRST AID POST

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LIGHT REFRESHMENT RESTING PLACE

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NO THROUGH ROAD NO THROUGH SIDE ROAD

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PARK THIS SIDE PARKING LOT MOTOR
CYCLE & SCOOTER

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PARK LOT CYCLE PARKING LOT CARS

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FLOOD GAUGE

33.  The design of route marker signs for national highways has
been standardized in India by the IRC. It consists of a shield
painted on a rectangular plate 450 mm X 660 mm. The sign
has a yellow background and all letters, sign and border are
painted in black.
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34.  Location of signs :
 In India, traffic signs should be located on the left side of the
road.
 On multi-lane carriage ways, they may be repeated on the
other side of the carriage way.
 On wide expressways, overhead signs may also be provided.
 On hill roads, traffic signs are normally fixed on the valley
side of the road. The signs are usually mounted on posts.
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35.  Location of signs :
 As per IRC: 67 -2012, for all roads, the extreme edge of the
ground mounted sign adjacent to the roadway shall be at a
distance of 600 mm to 3 m from the carriageway or paved
shoulder edge. For road with curbs, it shall not be less than
300 mm from the curb line.
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36.  Location of signs :
 As per IRC: 67 -2012, for kerbed roads, the bottom edge of
the lowest sign shall not be less than 2.1 m and not more than
2.5 m. On roads without kerbs, the bottom edge of the lowest
sign shall not be less than 2.0 m and not more than 2.5 m
above the crown of the pavement. To improve the visibility of
the signs on multi lane roads, the minimum height of the lower
edge of the sign should be kept as 2.5 m above carriageway.
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37.  Location of signs :
 Table gives distances at which signs should be fixed on rural
roads, in advance of the hazards warned against.
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Plain and rolling
terrain
Hilly or mountainous
terrain
On National and state
Highways
120 m 60 m
On Major District roads 90 m 50 m
On other district roads 60 m 40 m
On village roads 40 m 30 m

38.  Colour for signs :
 Signs shall be provided with retro-reflective sheeting and/or
overlay film as given in IRC-67. The reverse side of all signs
shall be painted grey.
 The sign post shall be painted in 250 mm wide bands,
alternatively white and black. The lowest band next to the
ground shall be in black.
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39.  Colour for signs :
 The mandatory and warning signs shall be provided with
white background and red border.
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40.  Colour for signs :
 Colour pattern for direction information signs is given in table.
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Road type Background Arrow/Border/Letters
Expressway Blue White
National Highway (NH) Green White
State Highway (SH) Green White
Major District Road (MDR) Green White
Other District Road (ODR)
Village Road (VR)
White Black
Urban/City Road Blue White

41.  Material for signs :
 Concrete shall be of M 25 grade
 Reinforcing steel shall conform to IS : 1786 requirements
 The plates and support sections for the sign posts shall
conform to IS : 226 and IS : 2062
 The plate thickness of shoulder mounted ground signs with a
maximum side dimension not exceeding 60 mm shall not be
less than 1.5 mm for aluminim sheet and 3 mm for ACM sheet
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42.  Road markings are the lines, patterns, words of other devices
for control, warning and guidance of information of road
users.
 IRC has standardized these markings in IRC : 35-1970.
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43.  Controlling and guiding traffic.
 They promote road safety and bring about smooth and
harmonious flow of traffic.
 They serve to supplement the messages conveyed by road
signs and signals.
 They convey the required information to the driver without
distracting his attention from the carriage way.
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44.  Pavement or carriage way markings may generally be of white
paint.
 Yellow colour marking are used to indicate parking
restrictions and for continuous centre line marking.
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45.  Centre line :
 These are meant to separate the opposing streams of traffic on
undivided two-way roads on NH and SH, with two or three
lanes, single broken lines of width 0.1 m, and 3.0 m segments
and 4.5 m gaps may be painted on straight stretches.
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46.  Lane lines :
 These markings divide the carriageway into separate lanes on
either side of the centre line. This helps to guide the traffic and
regulate it.
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47.  Stop lines :
 These are meant for vehicles to stop near the pedestrian
crossing, signalized intersection etc. where vehicles have to
stop and proceed.
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48.  Cross walk lines :
 These markings are provided at important intersections to
facilitate pedestrians to cross a road. The width of pedestrian
crossing may be between 2.0 and 4.0 m.
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49.  Such type of markings are provided on horizontal curves and
summit curves on two and three lane highways where
overtaking maneuvers are prohibited.
 The marking for a “no overtaking zone” consists of a
combination line along the centre line.
 The combination line consists of a double line, the left hand
element of which shall be a solid barrier line.
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50.  The right hand element will be either a normal broken centre
line or solid barrier line. Where a solid barrier line is to the
right of the broken line the overtaking restriction shall apply
only to the opposing traffic. If both the lines are solid lines, no
overtaking is permitted in both directions.
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51.  Usually pavement edge line marking is done for pavement
without kerbs. They serve as a visual guidance for the drivers,
indicating to them the limit up to which the driver can safely
venture.
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52.  Marking on the kerb indicate certain regulation like parking
regulation. Marking on the kerb and edges of islands with
alternate black and white line increase the visibility from a
long distance.
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53.  Physical obstruction on or near the roadways are hazardous
and hence should be properly marked. Typical obstruction are
supports for bridge, level crossing gates, signs and signals,
traffic island, narrow bridges, culvert head walls, etc.
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54.  Reflector markers are used as hazard markers and guide
markers for safe driving during night. Hazard markers
reflecting yellow light should be visible from a long distance
of about 150m.
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55.  Traffic signals are provided at road intersection. These are
control devices which could alternatively direct the traffic to
stop and proceed at intersections using red and green traffic
light signals automatically.
 The main requirements of traffic signals are to draw attention,
provide meaning and time to respond and to have minimum
waste of time.
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56.  Maintain orderly flow of traffic.
 Reduce certain types of accidents.
 Improves safety and efficiency of movement of vehicles.
 Pedestrians can cross the roads safety.
 Provides nearly continuous movement of traffic.
 More economical than manual control.
 Stop heavy traffic to allow slow moving traffic to cross the
road safely.
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57.  The rear end collision may increase.
 Improper design and location of signals may lead to violations
of the control system.
 Failure of the signal due to electric power failure or any other
defect may cause confusion to the road users.
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58.  The traffic signals are classified into the following types :
 1. Traffic control signals
◦ A. Fixed time signals
◦ B. Traffic actuated signals
 2. Pedestrian signals
 3. Special traffic signals
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59.  Generally a traffic signal is composed of three lenses, arranged
vertically one above the other with red lens on top, yellow or
amber in the middle and a green lens at bottom. The normal
sequence of traffic signal is red, amber, green, amber, red and
so on.
 Red : Vehicle must stop
 Amber : Light about to change
 Green : Vehicles can proceed
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60.  The Indian standard on traffic signals prescribes the following
symbols for pedestrian.
 The RED standing man represent the don’t cross indication.
 The GREEN walking man represent cross indication.
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61.  The fixed time signals are set to repeat regularly a cycle of red,
amber and green lights.
 The timing of each phase of the cycle is predetermined based
on the traffic studies.
 These signals are the simplest type of automatic traffic signals
which are electrically operated.
 These signals are also called Pre-timed signals.
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62.  Simple in construction.
 Relatively inexpensive.
 Most successfully used in linked systems requiring a fixed
cycle length for a given pattern and speed of progression.
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63.  Inflexible and hence may cause avoidable delay.
 Required careful setting.
 Sometimes the traffic flow on one road may be almost nil and
traffic on the cross road may be quite heavy. Yet as the signal
operates with fixed timings, the traffic in the heavy stream will
have to stop at red phase.
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64.  Traffic actuated signals are those in which the timings of the
phase and cycle time are changed according to traffic demand.
 The vehicles on any intersection approach are sensed by a
detecting device (e.g. magnetic tape, loops or pneumatic pads)
placed in the road. By recording the timing the vehicles as
they cross the detector and by timing the interval between
vehicles, the signals are automatically adjusted to give
preference to the approach with the heaviest flow.
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65.  Usually reduces the delay.
 Usually increases the capacity.
 It is adaptable to short-term fluctuation in traffic.
 It provides continuous operation under low volume condition.
 It is most efficient for isolated intersections.
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66.  They are uneconomical. The cost is about two to three times
the cost of a fixed time signals.
 Detectors are very costly to install and present very difficult
maintenance problems.
 The actuated controller (complete electronic mechanism) is
much more complicated than fixed time controllers.
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67.  Fully actuated signals:
 These have detectors located on each approach and assign the
right of way to the various traffic movements on the basis of
demand.
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68.  Semi-actuated signals:
 Where traffic on heavy volume of high speed arteries must be
interrupted for relative light class traffic, semi-actuated traffic
signals are often installed.
 For these signals the detectors are placed only on the minor
street.
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69.  Cycle :
 A signal cycle is one complete rotation through all of the
indications provided.
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70.  Cycle length (C):
 The time required for one complete sequence of signal
indications (i.e. Red-Red/Amber-Green-Amber) is called cycle
length or time cycle. It may vary from 40 to 60 seconds
depending upon :
 1. Volume of traffic on approaches
 2. Width of the roads and intersection.
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71.  Interval:
 It indicates the change from one stage to another. There are
two types of intervals.
 1. Clearance amber interval
 2. Initial amber interval
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72.  Clearance amber interval :
 It is also called the amber time indicates the interval between
the green and red signal indications for an approach.
 They are normally have a value of 3 to 6 seconds.
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73.  Initial amber interval :
 It is also called all red and is provided after each amber
interval indicating a period during which all signal faces show
red and is used for clearing off the vehicles in the intersection.
 It is the interval between red and green signal.
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74.  Green interval :
 It is the green indication for a particular movement. This is the
actual duration the green light of a traffic signal is turned on.
 It is denoted by Gi
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75.  Red interval :
 It is the red indication for a particular movement. This is the
actual duration the red light of a traffic signal is turned on.
 It is denoted by Ri
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76.  Phase :
 A phase is the green interval plus the change and clearance
intervals that follow it.
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77.  Lost time :
 It indicates the time during which the intersection is not
effectively utilized by any movement.
 For example, when the signal for an approach turns from red
to green the driver of the vehicle will take some time to
perceive the signal and some time will be lost before vehicle
moves.
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