If you assume that driverless cars will work, this is a neat perspective:
If you live in a big city, go outside and look up and down the street. You can see hundreds of autos just sitting there doing nothing. Some of these cars move less often than once per week. I don’t live in a big city and my car moves 2 hours a day on a day of heavy use.
Now envision 5-10 years from now…you go out on the street and there are no cars…because there’s an Enterprise rent-a-car parking garage with hundreds of self driving cars two miles from where you live. They have a smartphone app that you press a button for what kind of vehicle you need and it shows up out front in five minutes.
There’s more here on the efficiency gains when humans don’t need to operate cars (we’ll need less of them). And trucks, too.