"Averroës, Kant, Socrates, Newton, Voltaire, could any of them have believed it possible that in the twentieth century the scourge of cities, the poisoner of lungs, the mass murderer and idol of millions would be a metal receptacle on wheels, and that people would actually prefer being crushed to death inside it during frantic weekend exoduses instead of staying, safe and sound, at home?" ― Stanisław Lem, The Futurological Congress
Though it's still early, I haven't made any real predictions—today seems like a good day to start. By the year 2025, few people will own cars. I'll go further, and estimate that there will be only one vehicle for every five people in the United States. This hinges upon the adoption of autonomous vehicles.
Consider transportation in Europe. Per capita, the United States consumes 2.5 times as much petroleum as Europe—most likely because there are more than twice as many vehicles per capita. I've heard anecdotes that Europe, indeed, has much better public transportation than even the best U.S. cities. European policy makers have tended to favor mass transit and improving walkability over other forms of transportation. If metropolitan bus fleets in the United States can be automated, they could be operated more cheaply—or expanded to offer more continuous service or more routes. With increasing petroleum prices, policies will have to favor more efficient use of fuel.
However, let's say you want access to a private vehicle—it may not be necessary to own one, outright. With cars able to drive themselves, one vehicle could easily serve many people in a day. There are already car sharing companies that could easily expand their business with fleets of driverless cars. Improved fuel efficiency may also extend the time that oil will remain cheaply available—at least, it could smooth the transition to a post-petroleum economy.
