What is needed in urban (and even suburban neighbourhoods) is efficient transport. If a minibus system with an autonomous driver were available with reasonable (under 5 minute) headings and better than human driver delivery times, I suspect most people would opt for it rather than their own car. Traffic would be reduced and parking would no longer be as much of a problem. Helsinki is currently the home prototype system of this sort, but with human rather than autonomous drivers.
Nothing, unless the autonomy extends to busses/trains/etc (busses seem like a bad idea), then public transport could get even better.