And this is why most people will probably have a ride sharing membership with some sort of millage allotment with Uber, Lyft, Google, Apple, Chevy, Ford, Nissan, Lexus, etc. I will pay the company for 1000 miles of transportation about what my cost of owning the same vehicle will be. (There will be lots of competition, there will be a lot of incentive to undercut competitors for market share, so the price should be about the same as owning my own vehicle.) I'll never have to stop for gas, take it in for maintenance or repairs, park it myself at my destination, pay for parking, have a garage, worry about break-ins or theft. I'll never need to worry about the vehicle breaking down, because if it does, the service will send a replacement car and have their tow service take care of it.
And the company will be responsible for the insurance and any liability for operational error.
If somebody owns their own car, it will come with a disclaimer that if you modify the auto-driving system, and it malfunctions and causes a wreck, then you better have insurance that will have had a clause that prevents you from messing with said system, which means you will be paying the rate you would if you were operating the vehicle instead of the rate for your car using the manufacturer's auto-drive system.
For self owned cars, it should suffice that there is a warning signal that indicates a problem with the car, and when an error occurs, the vehicle move to a safe location (if needed), and the owner either can call for assistance, take manual control, or reboot to see if the fault is corrected. The system must refuse to drive the vehicle if there is a problem with the auto-drive, and the user will be forced to manually drive until such time as they get the problem with the auto-drive corrected.