Urban planners talk about two visions of the future city: heaven and hell. Hell, in case it's not clear, is bad—cities built for technologies, big companies, and vehicles instead of the humans who actually live in them. And hell, in some ways, is here. Today's US cities are dominated by highways there were built by razing residential neighborhoods. Few sidewalks and fewer bike lanes. It's all managed by public policies that incentivize commuting in your car. Alone. Trapped in traffic.