I don't see automated cars reducing the number of parking spaces needed.

If you have 150 people in a store, you're still going to have almost that many cars waiting outside to take them home. It will be more efficient for the cars to just wait, than it would be to release a car from the store only to send another car back in 15 minutes. If the stores don't have parking, the cars will just go round in circles on the streets near the stores causing huge congestion.

Cars are still going to need a place to park both near a users home and near their destinations. You're going to see huge parking lots/decks pop up with charging stations to keep all those cars juiced.

Automated cars are going lead to huge congestion issues as the cars make almost 50% of their trips empty.

If a family is going to try to survive with one car, that car will take bread-winner to work, comes home empty, Takes kids to school, comes home empty, Goes to store empty, Drives home with ice cream cake and bag of potatoes in drivers seat. [[placed there by robot at store. Potatoes too heavy to be delivered by drone aircraft) Car then has to collect kids, and collect bread-winner using 4 more trips.

You may be able to live with one car, It's lifespan in years will be seriously shorter than it is now. Cars have about 250,000 miles in them, this will only slowly increase.

We'll also see the effect of surge pricing at commuting time. It will probably be cheaper to buy your own car, if You want to get to the office the same time everyone else does. Rides to work and school will be more expensive at rush times if you don't own your vehicle.