You still have to power the thing. Declining oil production and the limitations of battery power are going to be a severe limiting factor that will influence the way we roll out self-driving automobiles.
Fleets of self-driving vehicles nearly eliminate the problems with battery power; they can easily schedule when they need to return to the station to swap out their battery packs for fresh ones.
I still think technology is winning the resource depletion race, even if we ignore the fact that it's really starting to look like oil production isn't actually near the end of its road yet. And if we don't ignore that, the likelihood that gas (or more broadly "energy") will just be "too expensive" for people to want to jaunt about anytime in the next 20 years seems to be decreasing rather than increasing. A great deal of our current apparent shortages of various things are 100% self-imposed.
Presumably a robot could also connect to overhead or embedded wires, reducing the size of batteries to that needed for areas without that infrastructure.
Buses in SF run totally with overhead wires. You see the drivers having to reconnect to them when they pop out.
