Cities were designed around that dream. Frazer quotes University of Houston historian Martin Melosi, who said that roughly half of the space in American cities has been given over to roads, parking lots, parking spots, gas stations, traffic signals, and other things pertaining to cars. And at the same time, space for other forms of transportation — like sidewalks — were squeezed out. Even the sidewalks themselves are designed to resist change; large concrete slabs, they don’t lend themselves to being changed around. Making an infrastructure change can cost millions, a price many cities won’t or can’t pay.

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