Hence, if your car doesn't need to wait for you where you got out, then city-centre car parks disappear and retail gets remade (such of it as survives the shift to ecommerce, of course). No more worrying about parking. If you don't need to worry about parking yet can be driven there directly and affordably, how much travel shifts from public transport to cars? How many people visit a busy central area they might previously have avoided for that reason (the West End of London, for example)? But then, where does that car go afterwards - does it drop you off for dinner and drive off to a cheap carpark, or does it spend the next few hours driving other people around for a fee? The more autonomous cars there are, the more appealing on-demand becomes. Quite where the second-order effects end up is hard to predict - for example, where does it leave public transport if routes start emptying out, and what does that mean for people on very low incomes?
Like I said before: driverless, on-demand fleets of electric cars will transform humanity the same way the steam engine created cities and the automobile created suburbs.