It is a tragic failure of imagination to believe that a driverless car will offer the same opportunities as a bus or subway. Yes, I'm sure there will be a public transit version of them. Yes, I'm sure that you'll occassionally have to reject one because there's a pool of vomit it in it. But, no, it'll be nothing like walking down the street for a bus, or, for a young woman, hailing a taxi driven by a stranger, at night.