One study suggests a single self-driving car could replace up to 12 regular vehicles. Indeed, many urbanists predict that fleets of robocars could become so reliable that many, many people would choose not to own automobiles, causing the amount of parking needed to drop through the floor.

“Parking has been this sacred cow that we couldn’t touch—and now we can touch it,” says Gabe Klein, who has headed the transportation departments in Chicago and Washington, DC. He sees enormous potential—all that paved-over space suddenly freed up for houses and schools, plazas and playgrounds, or just about anything. “All that parking could go away, and then what happens?” he asks. “You unlock a tremendous amount of value.”