Modeling Traffic in South African Cities
The article I read discusses a severe traffic problem occurring in South Africa. In the cities of Johannesburg, Durban, Pretoria, Cape Town, Mother City and more, highways have been facing bumper-to-bumper traffic. One wrong turn can cost hours in these very congested cities which prevents citizens from arriving to work on time. What comes as a surprise to the people of South Africa is that it has been suggested that by closing more roads, the flow of traffic can be optimized. The article explains how the concept behind this odd occurrence is known as the Braess Paradox. With extra roads, because every driver is trying to minimize their own travel time, their interests conflict with one another and no driving time is lowered. If the drivers were to divide who takes which route evenly, then total driving time would be lowered. However, as drivers are self-interested, everybody chooses to use the fastest route causing the route to actually increase total driving time.
This article clearly references concepts discussed in class such as Network Traffic, Nash Equilibrium, and Braess’s paradox. Braess’s paradox explains why, even with so many roads, these cities experience such terrible traffic. The writer explains how, when all drivers try to take the fastest route, a Nash Equilibrium is created. At this Nash Equilibrium, no individual driver has an incentive to switch routes. However, as they are all taking the same route, travel time is increased. The article even provides a visual representation of how travel time for a given group of cars can, somewhat counterintuitively, be increased by introducing an alternate route.