I once proposed that for airport rental cars - you'd call for a rental car, and it would self-drive, slowly, from the rental yard to the terminal. Then the renter takes over driving. At return, the driver gets out at the terminal, pushes the "done with rental" button, and the car drives itself, slowly, back to the rental yard.

Major destinations with big parking lots could be on the system. Convention centers, sports stadiums, major hotels. Again, the driver gets out at a convenient unloading point and the car drives and parks itself.

All autonomous driving would be around 15-20mph. At that speed, slamming on the brakes is an adequate solution to almost all problems.

But airport security was too touchy an issue a decade ago. What if one of the self-driving cars had a bomb in it? Might be worth another look now.