How Barcelona “superblocks” can improve traffic by closing off roads
Barcelona is introducing a radical plan to transform city streets and return them to the people. The plan uses the concept of a “superblock”, a square of 9 traditional city blocks where the inner four intersecting roads are closed off from vehicles and reserved as space for pedestrians. This plan will be implemented throughout the city and plans to reduce traffic congestion by 21% in Barcelona. In addition, the plan hopes to make the city over pedestrian-friendly, increase environmental quality, reduce noise pollution, and reduce car accidents.
One may think that removing access to roads would increase traffic congestion; however, as we discussed in class, a game theoretic analysis reveals that this is not necessarily the case. Braess’s Paradox reveals that there are cases where adding additional roads can actually increase traffic congestion assuming individuals make a selfish decisions. The basis of this “paradox” is a game theoretic approach where the equilibrium travel time of the augmented network is actually worse than before, yet the situation ensures that the other routes are suboptimal. The inverse of Braess’ Paradox implies that removing roads can actually improve travel time, and that is what cities are trying to do.
This phenomenon is explained succinctly in the article by Michael Gastner, a computer scientist at the Santa Fe Institute, who says “Because selfish drivers optimize a wrong function, they can be led to a better solution if you remove some of the network links.” Indeed, the article cites an instance in Boston, where the commute between Harvard Square to Boston Common could be improved by closing off six words, as well as a similar instance in Singapore. The city government of Barcelona hopes to replicate these previous successes and transform the city experience into a more enjoyable, green, human-focused one while simultaneously removing traffic.