Faced with intolerable congestion and noxious pollution, cities around the world are rethinking their reliance on cars. In the US a loosely organised livability movement seeks to reduce car use by reconfiguring urban space into denser, transit-oriented, walkable forms. Through a detailed case study of San Francisco, Jason Henderson examines how this is not just a struggle over what type of transportation is best for the city, but a series of ideologically charged political fights.