And this is one reason they will be better to rent than own. How many times have you had a perfectly drivable car with some failing sensor? In an autonomous vehicle, such sensor failures will essentially brick the vehicle until it's fixed.

If the sensors are redundant enough, a failure or two shouldn't prevent the car from driving; it'll just drop you off and drive itself to the nearest repair place.

Plus this will make these cars safer. There are thousands of people who drive cars that should not be on the roads.

Actually, rockets work like this.

On that note, here's an interesting interview with the analysis lead for Mission and Fault Management on the NASA’s Space Launch System program: http://omegataupodcast.net/100-system-health-mgt/