I think ideal progression would be: 1st step: Everybody have their own cars and drive them manually (current situation, too many cars) 2nd step: Minority of t

I think ideal progression would be: 1st step: Everybody have their own cars and drive them manually (current situation, too many cars) 2nd step: Minority of the private individuals now own self driving cars (next step) 3rd step: Majority of the private individuals now own self driving cars. (almost all cars are self driving now!) 4th step: Commercial entities enter the self driving car sharing market as an option to privately owning a car, you pay for a subscription and have access to a fleet of cars. 5th step: People stop buying cars and the only cars on the road are owned by commercial entities, which can be rented at will. 5th step would be ideal, as this also eliminates the need of parking spaces within the city! Whenever their services are not needed, the autonomous cars can just navigate to a parking facility/hangar in the outskirts of the city. The amount of cars on the streets can be increased and decreased at will.