Closing Roads Sometimes Improves Traffic Flow
"At first blush, this study seems dissonant with findings that traffic flows can be improved by increasing vehicular anarchy. As I noted a few months back, there is considerable evidence that removing all traffic controls – lights, signs, road markings, and even the distinction between streets and sidewalks – can actually make traffic move more smoothly, as well as cut down on the number of accidents and increase the area's economic vitality. The idea behind these "shared streets," which have been successfully deployed in many European cities, is that the lack of traffic signs makes you take personal responsibility for directly negotiating with the pedestrians, cyclists, and other cars around you, instead of, say, gunning it through an intersection just because you know you have the light.
But maybe these two traffic models have more in common than it first seems. Both encourage individuals to drive more slowly so that everyone gets to his destinations faster. Both favor a holistic approach to traffic, one that designs from the perspective of the overall flow rather than that of an individual driver. And both open up more space for pedestrians."