According to industry consultants McKinsey & Company, once autonomous vehicles go mainstream, the need for parking space in the United States could reduce by more than 5.7 billion square meters. That's nearly the size of Delaware. There are many reasons for this. For one thing, traditional cars are parked 95% of the time, on average. Once driverless cars are widely available, private car ownership could become the exception to the rule, with people sharing cars with friends and family or paying a subscription fee for on-demand transport. That could slash the number of cars on the road—and in parking lots. University of Texas professor Dr. Kara Kockelman told Curbed, "I think we'd lose 50 percent of parking demand. If everyone [stopped owning a car], you could get rid of 7 out of 8 cars on the road, so you'd need an eighth of the spots."
But even the driverless cars that would be around would take up less parking space than traditional cars. That's because they drop you off before they park themselves, so parking spaces don't need to leave room for the cars to open their doors.