City traffic

Real reason of traffic jams in cities are explained with solution to have long-term traffic-free roads in highly populated cities.

Traffic does not depend on number of vehicles on road, wideness of the road and time of the day. Traffic only depends on number of blockages and duration of blockages of vehicle movement. If there are more blockages, there will be slow vehicle movement. If there is long duration of blockage, accumulation of vehicles will be more. Combination of slow vehicle movement and accumulation of vehicles cause all types of traffic jams.

Blockage includes traffic signals, road humps, potholes, rough road, blind curves, vehicle breakdown, cows, other domestic animals and so on. Only traffic signals are taken care in the solution as other things are one time task to clear.

A city’s development depends on its traffic. Traffic jams on city roads hinder development of the city. As city gets developed, number of vehicles increases. That does not mean that there will be heavy traffic. Traffic and traffic jams depend on infrastructural plan of the city.

Emergency

When we talk about emergency, only ambulance comes to our mind. When ambulance is seen on the road, we give way. What about many more emergencies on the road? When somebody is critical at home, they don’t call ambulance and wait for it to come and take the patient. They take the patient to hospital in their own vehicle. Isn’t it an emergency? 90% of patients with medical emergencies (other than road accidents) are taken to hospital in car or auto. Just because it is a private vehicle, we don’t feel their urgency. It is very critical to reach on time for a person who is attending an interview. What about a student who is going for an exam? If there is traffic jam, whether he/she is travelling by private vehicle or public transport, will the college allow the student to write exam and give the lost time?

Common solutions

Common solutions that many people suggest while talking about traffic are:

Starting early
Starting early is not a solution for traffic problem. What is Starting early for medical emergencies? Starting early is solution only for individuals. Starting 3 hours early on Friday evening on few roads of Bangalore does not guarantee you to reach railway station on time. If it rains on that day, the hope is completely lost. What is starting early in this case?

Widening of roads
Widening of roads can only allow accumulation of more vehicles. It can never solve traffic problem.

How traffic jams happen?

The following simple calculation shows how traffic jams happen.

Assumptions:

100 cars that are distributed equally on 1km stretch of a single lane road are moving with 60kmph speed.

Road length: 1km (1000 meters)
Number of cars: 100
Car length: 3m
Gap between cars: 7m
Speed of cars: 60kmph

If there is a junction with green signal for 60 seconds, all these 100 cars can cross the junction in 60 seconds.

If a junction on the road gets a red signal for 60 seconds, all cars will come and get adjusted in front of the signal in a stretch of 300 meters.

After red signal, if it gets green signal for 60 seconds, can all 100 cars cross the junction? No. Because each car has to start with 0kmph speed and increase its speed slowly. If each car takes 3 seconds to start and move forward and give enough space for next car to move, only about 20 cars can cross the junction in 60 seconds. So the remaining 80 cars come forward and get adjusted near the junction. In this gap of 2 minutes, many other cars also come and join the already waiting vehicles. This accumulation increases as number of vehicles on the road increases. Duration of red signal is much more than duration of green signal because 3 directions get green signal while we are waiting in red signal. So because of long red signal, the accumulation time and thereby number of accumulated vehicles will be very high.

If always a green signal is given at a junction, there will not be any accumulation of vehicles and there will not be any traffic jam. In this case, according to our above calculation, about 6000 cars can cross the junction every hour on a single lane road. If it is two-lane road, about 12000 cars can cross the junction every hour.

Solution: Signal free roads

60% to 80% of traffic congestion can be reduced by making one lane each side completely signal free on major roads of the city. The procedure is as follows:

• Identify few roads of the city as major roads. All the major roads of the city should be made signal free. When two major roads cross, that junction should be made complete signal free junction.
• Identify all major and minor junctions with respect to both vehicle movement and pedestrian movement. Number of vehicles crossing each junction in each direction should be recorded for a particular period to label each junction as minor or major. This data will give idea of which roads and junctions will go signal free.
• Reduce number of junctions by closing junctions at small road crossings. A junction that has negligible vehicle movement in two directions compared to other two directions is a minor junction. So it can be made straight road by blocking two directions.
• At every junction, construct an over bridge of two lanes, one for going and the other for coming back. On a road with 4 lanes, two lanes will be used for signal free straight road and other two lanes will be used for left and right turning vehicles.
• Below the over-bridge, it will be a signal controlled junction. Side road vehicles and vehicles of main road that needs to turn left or right will be moving according to the signal.

Pedestrians

A city road plan or traffic control plan without including pedestrian crossing will be a failure always. Demand for pedestrian crossing is not same at all junctions. So some level of analysis is required before planning for it.

• Similar to vehicle movement, statistics of pedestrian movement at every junction has to be studied to decide whether to install a pedestrian crossing bridge or a pedestrian signal at the junction.
• All signal junctions below over-bridges will have pedestrian crossing option in the signal. Pedestrian crossing is allowed at some of the other junctions where vehicle crossing is not allowed. Pedestrian crossing will be allowed only through signals at all junctions.
• Where very high number of pedestrian crossing is expected, a pedestrian crossing bridge will be constructed across the road. It can be an under-pass or overhead iron bridge.
• Signals of all the junctions of a main road will be synchronized. This synchronization is very important to control the traffic. With this synchronization, all vehicles will stop at same time and start at same time so that there will not be any accumulation or traffic jam problems.
• Synchronization of all signals of the main road with real clock time will help pedestrians to plan their tasks. They can avoid waiting on the road and utilize that time for something else.
• 1 minute is given at every 5 minute cycle for pedestrian crossing at signal junctions below over-bridge. 1 minute is given at every 15 minute cycle for pedestrian crossing at all other junctions where vehicle crossing not allowed.
• LED timers will be displayed at all junctions so that pedestrians will know exactly when they are going to get their turn and also the time left for them to cross.

Benefits

With signal free roads, one hour journey can be completed in 15 minutes. That means:

75% reduction in travel time
All emergencies are taken care automatically. Productivity of people will improve and they get more time for their life.

75% reduction in fuel consumption
Huge reduction in transportation/travel cost. Fuel savings of all vehicles of peak hour can be used for national development.

75% reduction in air pollution
Reduction in air pollution reduces lot of health hazards of humans and all other living creatures. And also helps in urban development. You can read Urban Air Pollution article to know more advantages.