Three physicists claim that shutting certain Boston roads at rush hour could actually improve traffic flow. Unfortunately, we'll have to wait for the next issue of Physical Review Letters to learn which roads. In the meantime, we have this synopsis from the Economist of the paper by Hyejin Youn and Hawoong Jeong, of the Korea Advanced Institute of Science and Technology, and Michael Gastner, of the Santa Fe Institute, who spent quite a bit of time analyzing traffic flows in Boston, London and New York. Locally, they looked at different ways to get from Harvard Square to Boston Common:
... Modifying the road network could reduce delays. And contrary to popular belief, a simple way to do that might be to close certain roads. This is known as Braess's paradox, after another mathematician, Dietrich Braess, who found that adding extra capacity to a network can sometimes reduce its overall efficiency.
In Boston the group looked to see if the paradox could be created by closing any of the 246 links. In 240 cases their analysis showed that a closure increased traffic problems. But closing any one of the remaining six streets reduced the [total commute time] of the new Nash equilibrium.
Via John Keith.