To the drivers in Delhi


I am going to do something laughable. I will attempt to coax the junta of Delhi to change just one of their driving habits by presenting a rational argument.

Before I lay out the rationale, here is the summary: I’d like you, the people of Delhi, to stop adding new ‘lanes’ to road at a traffic light by shoving your vehicles at the sides diagonally in an attempt to make it ahead of the car to your side.

First, let me explain a concept: The flow or traffic (or fluid for that matter) through any particular cross-section of road is the largest when unrestricted and is in a single direction. That’s how faucets work – no in a kind of reverse way ?

One of the most important principle in traffic is to avoid collisions. This is done by maintaining adequate separation from all other adjacent vehicles. Imagine a scenario on a two-lane road where no vehicle can possibly change lanes. In this scenario, the only separation a vehicle needs to worry about is front and back. Now by allowing for vehicles to change lanes, the need for maintaining sufficient sideways separation becomes important. If the vehicle in front of you in the adjacent lane wants to come in to your lane you need to either reduce your speed or (if you’re a Delhi driver) increase your speed making the other guy wait for you to pass. Either way the average speed of the two lanes reduces, adversely impacting the throughput of the road.

Extending the above scenario to a case where there are lanes on either side of you, the potential reduction in speed is even greater because you could have vehicles come in from either side. You get the drift. You could argue that vehicles can instead indicate their intention of changing of lanes beforehand. That does allow for inter-vehicle separation to be kept lower but it nevertheless does impact average speed on either lane albeit a bit lesser.

Now imagine what happens when a lot of vehicles are waiting at a red light waiting for it to turn green. The throughput of the road (number of cars that pass through in one unit of time) essentially depends on the speed of the vehicles in front. If they are slow, the entire traffic behind them is slow.

So what happens when another vehicle edges at the side of the traffic light hoping to get ahead of the one already in waiting ? It adds an additional lane to the traffic and due to a greater need for separation causes the vehicle already at the light to be even slower than what it is. This in turn reduces the throughput of the *entire* road affecting every vehicle. Perhaps two or three vehicles do gain by edging from the sides and the impact is the reduction in speed of about 50 other vehicles.

In my book, this is not cool. So I urge you to consider not creating a new lane by edging your vehicle in.  Do this for the greater good. Do it for the warm fuzzy feeling that you did not cause agony to about 50 other vehicles as well.

The downside ? That punched-in-the-stomach feeling that some other sucker still did that leaving you in the slow lane. If only I knew the way around that…