“The essential economic and social purpose of cities is bringing people together, taking advantage of opportunities for interaction and agglomeration economies. Cities perform this function in two principal ways, by providing accessibility (putting people close to one another and to common destinations), and through mobility, the ability to move easily from one point to another.
National discussions of how to make cities work better have tended to focus on making it easier for people to move, which has had the paradoxical effect of leading cities to be less dense. And the measures we use to describe how well city transportation systems work have reflected this bias toward mobility. In that sense, the emphasis on mobility measures has driven us apart. Putting more emphasis on accessibility can bring us closer together.”