In class, we briefly discussed how road networks play into game theory. We kept our model of real-world road networks relatively simple, limiting our congestion-reducing strategies to road construction and toll and subsidy implementation. We never delved into other traffic control innovations, such as the traffic signal, to which the following article pertains:

http://www.trafficpd.com/Publication/Signal1.pdf

The article is directed toward a Pennsylvanian audience, but it is nevertheless relevant to our nation’s and even the world’s traffic issues.

We all know traffic is an enormous problem in many major cities, and since the population is always increasing, there’s no mitigating the number of cars on the road until a better, more attractive method of transportation is invented. As we learned in class, adding roads will not necessarily solve traffic congestion (Braess’s Paradox), and this is a commonly accepted fact among traffic planning engineers, who would recommend new road construction only as a last resort. Traffic signals are one of the more efficient or effective solutions to traffic congestion that provide an alternative way to get around Braess’s Paradox. By sequentially assigning “the right-of-way to vehicles approaching an intersection from various directions,” traffic signals allow vehicles from side roads to merge into main roads, in addition to allowing vehicles to more easily make left turns.

In class, we neglected the fact that cars would somehow have to merge where more than two roads intersect, which if included in our analysis would have added a factor to the travel time. Traffic signals address this neglected effect, or oversimplification. Despite the theoretically high effectiveness of traffic signals, location, of course, is what really determines effectiveness. Like road construction, if placed at the wrong location, signals can cause unnecessary delays. They can even increase the likelihood of accidents, which is why sight distance and accident history for the area must be taken into account when deciding whether a signal is necessary.