Traffic signals in India- What is the first thing that comes to your mind when you hear the civil engineering subject? The one who disturbs the rhythm of your journey without your permission, right? Jokes apart, it plays a relevant role in the traffic management of the country. Being wide and heterogeneous in nature, it is not a cakewalk to control the huge population including you and me.

Now, before we get into the details, let me tell you that traffic signals in India and traffic signs are not the same!

Traffic sign v/s signal

There is often a misconception that traffic signals and signs are the same. But the truth is that both are traffic control devices, but different. Traffic signs are placards provided to guide you in the journey whereas signals are placed only at the main intersections to manage the traffic.

For example, imagine a junction where heavy traffic is found usually in the north-south direction. If there is no much traffic in the east-west direction, traffic signals are not required at the junction. Yeah, simple logic.

The importance of traffic signals

Growing traffic density and insufficient expansion of available road space have resulted in congestion and related delays during peak hours in urban roads around the world. It results in increased travel time, which reduces the performance of the transport network. This problem is more serious in urban roads with frequent intersections, which are the main points of conflict for traffic movements. Traffic signals at the main intersections can curb the situation.

Mechanism of traffic signals in India

The design of signals will be such that it shows a green light where there are less traffic and red where there is more traffic. It also considers the pedestrians who may cross the road in between and allots minimum of 10 to 15 seconds for that. Another interesting fact it considers is that the overall waiting time should not exceed 120 seconds at normal situations, which is the average tolerance level of humans.

Advantages of traffic signals in india

• Provide orderly movement
• Minimises the number of conflicting movements
• Increase capacity
• Interrupt heavy traffic to allow other traffic to enter or cross
• The coordinate continuous movement of traffic at the desired speed
• Promote driver confidence

Okay. Let’s see the varieties now.

Types of traffic signals

Traffic signals are broadly classified into three.

a) Traffic control signals

These are the signal lights in red, green and yellow. Red to stop, green to go and yellow to get ready. Obviously, you have seen the rangoli of colors in your life.

Traffic control signals are futher divided into 3.

i) Fixed time signal

These signals operate at fixed time periods without considering the real time traffic.

ii) Manually operates

This type of signals are manually operated which makes it more reliable.

iii) Traffic actuated

This includes semi actuated and fully actuated signals. The timings are real time.

b) Pedestrian signals

These are the signals for pedestrians who cross the road or walk along the footpaths.

c) Special traffic signals

All other signals which don’t come in the previous categories belong to this type.

Types of traffic signal system

The whole system of traffic signals in India are divided as follows.

1. Simultaneous system
2. Alternate system
3. Simple progressive system
4. Flexible progressive system

We have seen different faces of signals. Now, let me get you the warrents for traffic control signals.

Warrants for traffic control signal in india

1. Minimum vehicular volume warrant

Case 1- The average traffic volume for 8 hours on both approaches should be at least 650 vehicles/hr on major streets with single lane and 800 vehicles/hr on streets with 2 or more lanes.

Case 2- Minor street (One direction atleast 200 veh/hr- single lane

                                                                   250 veh/hr- two lanes

Case 3- >60kmph, 70 percent increase in major case

2. Interruption to continuous traffic flow on major street with 1000- 1200 veh/hr that there is undue delay or hazard to traffic on minor road with a traffic 100- 150 veh/hr in one direction only during any 8 hours on average day

3. Minimum pedestrian volume movement

4. Accident experience warrant

5. Combination of warrants

Lastly, in areas where there is huge traffic, ramps are preferred. But ramps are not suitable to heterogeneous traffic through some of the planned cities have implemented them. Its better to use flyovers and over bridges in these cases.

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