[ufo]

Cars are carry less people per area of road than buses do and it's even worse for self driving cars that are empty half the time.

[freddref]

My car is empty 99% of the time, it could be very highly utilised by the general public.

[wolfram74]

Given the current lower bound of one passenger in personal vehicles the process for using driverless cars needs to incentivize car pooling to the point that the average occupancy of traveling cars is considerably above 1 to make up for all the cars taking up road space while empty.

There is a possibility of municipalities having many mid to large vans that do routes at higher frequencies because they don't need drivers.