A Shallow Dive into Traffic Congestions
It's easy to hate traffic, but there's more to it than it meets the eyes
Traffic is a menace. We have accepted it as a ‘fact of life’. Before Google Maps, knowing how to avoid traffic was an art. It still is, but much easier, when you have an app churning out the fastest route after processing petabytes of data. Within a city, you don’t describe distance in kilometers, but in minutes. ‘The nearest bar is 5 mins away’. Why is that? Because ease of travel doesn’t depend on how far you have to go, but how bad the traffic gets on the route that you have to take.
In theory, roads are public goods i.e. “a commodity or service that is provided without profit to all members of a society, either by the government or by a private individual or organization.” Public goods are also supposed to be non-excludable and non-rivalrous. That seems like a moot point, when trying to merge into traffic at 0630 PM on a Friday. Roads have drivers, and drivers are competitive. And whenever there is competition, there has to be an optimum strategy to win the competition. Common sense dictates that, if you are the bold one and don’t care about side-railing another vehicle, you will probably merge into traffic faster than other ‘dumb’ drivers. There’s a fundamental problem in this kind of common sense approach — if all competitors decide to be bold, everybody loses. And we have the good old fashioned congestion. It’s a classic example of two agents choosing a strategy that leads to an undesirable outcome for both the agents.
Traffic Flow Equilibrium
Imagine a situation where everyone knows the roads in the cities. To go from point A to point B, there are two routes. Route A is the shortest distance and has six lanes. Route B is longer than A and four lanes. It’s the time of the day, when everyone has to drive to work. Which route would you choose? To answer this question, one should remember that whatever decision you take is based on information which is public i.e. if you think the decision is the best, then everyone else will think that decision is the best.
So, Route A has all the good things going for it. It will also be more crowded than Route B, simply because most people will prefer Route A because of its shorter distance and more lanes. So, you will be better off taking Route B. It is longer, but it’s not that popular. So, less chances of congestion on Route B. In the rush hour, Route A will exceed its vehicular capacity (vehicles per hour) and even the tiniest breakdown will lead to delays due to congestion. So, you are better off taking Route B. But, wait! Wouldn’t everyone think that way? Sure, you can assume that everyone’s an idiot, but that’s a questionable assumption to make.
If there are multiple routes between two points, the travel times between them will eventually come to an equilibrium i.e. travel times between Route A and B in the example, will eventually be equal.
Traffic Congestion and Traffic Assignment
A pedantic definition of traffic congestion will not add anything new to the general understanding of the term. It’s an all-too-familiar part of urban and semi-urban life. So many of us have wondered, while being late for work or for a date — why can’t the congestion be solved? Is it such a hard problem?
Why is it hard to solve traffic congestion?
Traffic congestion has seven root causes. Traffic jams can sometimes come out of nowhere. Solving the problem of traffic congestion has numerous aspect. It all comes down to cost. Reducing traffic congestion would require roads with increased vehicular capacity i.e. wider roads. Wider roads require more space. In a city, where every square feet of land is prohibitively expensive, ‘just make the roads wide’ isn’t an easy solution. The relocation of the commercial establishment away from the road isn’t the most pleasant business for City Planners.
Another way to reduce congestion (and save Earth!) is to make Public Transport Systems have larger coverage and capacity. However, that is prohibitively expensive too. Moreover, taking the Public Transport everywhere is a lifestyle and takes a generation to become mainstream (i.e. cool).
There’s a more difficult problem — a mathematical one. Traffic flow, is an interaction of selfish agents, all having the same goal — to reach their destinations at the shortest time possible. When you have agents, competing for a utility (i.e. road), strategy matters. A wrong strategy would eventually lead to a sub-optimal traffic flow, creating bottlenecks ergo congestion. There are various mathematical models for traffic flow assignment. These models differ from each other in terms of the underlying assumptions. An introductory presentation for Dynamic Traffic Assignment can be found here.
The State is bound to interfere with the traffic assignment. Traffic lights, sign-boards which prohibit you from taking a turn at certain times of the day, ‘No Parking’ signs which are dependent on the time of the day, roundabout turns are all examples of State trying to make an optimal traffic flow assignment.
What can we do as Drivers?
Traffic Congestion is a problem of immense complexity and simplicity at the same time. Drivers compete on the road to reach their destinations at the fastest time. It might seem counter-intuitive, but winning the traffic game requires co-operation. You should co-operate with your fellow drivers and with the State. Traffic rules are their for a reason. Chaos and high entropy maybe the natural states of the universe, but to have an unnaturally smooth traffic, you have to go against your instincts to be the alpha driver. Follow the rules. Rules keep the entropy of the system low, and in turn creates an ordered flow.
Order in traffic is more important than free flow speeds. If you can go an a constant speed of 30 kmph, that’s way better than trying to cut lanes at 60 kmph only to end up in a stop-and-go traffic.
An example, as described in the video below, is to keep a safe distance between you and the vehicle ahead. That way, you won't have to break adversely, which ultimately avoids creating a phantom intersection. Your brake, back-propagates and creates a traffic congestion out of nowhere.
Happy Driving!
Completely agree with the author on this that mass transit is one of the most effective solutions for traffic congestion. However wider roads I.e increased vehicular capacity don’t solve the problem of traffic congestion as people have a tendency to buy more cars if there is more capacity on roads. Case in point LA