Clive Thompson in Mother Jones:
The average automobile spends 95 percent of its time sitting in place. People buy cars because they need to move around, but the amount of time they actually do move around is tiny. So the cars are parked, and in multiple spaces: A car owner needs a spot near home, but also spots near other places he or she might go—the office, a shopping mall, Epcot.A 2011 study at the University of California-Berkeley found that the United States has somewhere close to a billion parking spots. Since there are only 253 million passenger cars and light trucks in the country, that means we have roughly four times more parking spaces than vehicles. If you totaled up all the area devoted to parking, it'd be roughly 6,500 square miles, bigger than Connecticut.
And finding one of the parking spaces is a PITA:
And worst of all may be the emissions that parking causes. Studies have found that anywhere from about 30 to 60 percent of the cars you see driving around a downtown core are just circling, looking for an open space to claim. (An IBM survey found that worldwide, urban drivers spend an average of 20 minutes per trip looking for parking.)
We are, [some experts] say, on the cusp of a new era, when cities can begin dramatically reducing the amount of parking spaces they offer. This shift is being driven by a one-two punch of social and technological change. On the social side, people are increasingly opting to live in urban centers, where they don't need—or want—to own a car. They're ride-sharing or using public transit instead.And technologically, we're seeing the rapid emergence of self-driving cars. Google's models have traveled more than a million miles with almost no accidents, and experts expect that fully autonomous vehicles will hit the consumer market as early as a decade from now. [...]
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."