If by self driving car you mean a car that can only drive itself after a programmer specifically resolves whichever breaking problem it had (which may or may not occur after your life has ended DUE to this very problem), then I guess they are here!
I’d say they’re here when the probability of being injured, at every level of severity, is less than that of a human driver, and the occasional “oops we’re stuck in a weird situation” problems (which happen to human taxis too) are similarly infrequent and tolerable enough that people consider the minuscule risk of inconvenience worth the ride.
