Braess’s Paradox Applied to the Real World
http://www.nytimes.com/1990/12/25/health/what-if-they-closed-42d-street-and-nobody-noticed.html
When intuitively thinking about traffic and commuting times, it is rational to believe that the addition of extra paths can lead to a decrease in commuting times and allow for less traffic. However, in INFO 2040, we have learned that quite the opposite can occur; this phenomenon is called Braess’s Paradox in which transportation infrastructures can be negatively affected as a collective when alternative paths are introduced.
I found an applicable example that occurred in the real world in New York City during the holiday period of 1990. On Earth Day of 1990, New York City’s Transportation Commissioner closed 42nd street, a heavily congested street infamous among New Yorkers. While the expected outcome is increased congestion throughout the city, this actually did not happen. Instead, traffic flow actually improved and no historic traffic jam was reported. As we learned during this class, in crowded conditions, drivers will try an alternative path which leads to the clogging of not only the original street, but also the streets that provide access to it. Thus, distributing the traffic through 42nd street onto other major streets did not make much of a difference.
This led to discussions among members of the academic world. Joel Cohen, a mathematician at Rockefeller University, interestingly noticed that this paradox does not always hold as non-congested traffic routes can actually be improved by adding additional paths. However, in congested networks, adding a new street makes things worse more than half the time. The moving entities that selfishly choose their path can reduce overall performance when extra capacity is added to a network. Furthermore, Cohen cited a German paper that reported the City of Stuttgart’s downtown traffic being worsened when a new street had been added.