Braess’s Paradox in 1990
webpage link: https://www.nytimes.com/1990/12/25/health/what-if-they-closed-42d-street-and-nobody-noticed.html
On Earth Day of 1990, the New York City’s Transportation Commissioner decided to close 42d Street, a well-known congesting street. At that time, all New Yorkers expected the decision will cause greater traffic jam. On the contrary, to everyone’s surprise, the traffic flow was even improved during that day! This is the real-world example of Braess’s Paradox, that is. when a network of streets is already jammed with vehicles, adding a new street can make traffic flow even more slowly. The reason behind the theory is that since all roads are already extremely congested, adding one more road to diverse drivers from one crowded road to another doesn’t ease the traffic environment. Nevertheless, the Braess’s Paradox is the conclusion based on a very simple statistical model. When using more sophisticated mathematical model to describe the traffic system, this theory doesn’t always hold true.
This article more specifically discussed the Braess’s Paradox which we’ve covered in the lecture about Game Theory. By giving the concrete example of the street 42d in New York City, I understood the motivation and the reason behind such a counter-intuitive theory. To compellingly convince readers, the article even mentioned another experiment conducted by Dr. Cohen and Dr. Kelly. When the V-shaped street whose two end both lead drivers to jammed in one side of the lane, adding one street to connect the previous two ends tends to further slow people down. More noticeable, this article further discussed the drawback of Braess’s Paradox: uncertainty in more sophisticated scenario.
Although the article was published during 1990, it’s still worthy for us to get a sense about the Braess’s Paradox 30 years later.