California is letting the autonomous car genie out of the bottle in the expectation that they will collect improved accident data that will bolster their position. Maybe that will happen, but first they will need to deal with accidents that kill people due to self-driving errors. It's already happened once, and will no doubt happen more as time goes on.
Imagine you have lost a loved one because someone else's auto-drive car screwed up. Will you be willing to just accept the loss as the price of progress? Unlikely. Most people will decide their loved one would still be alive were it not for the new law allowing such cars on the road, and will go to court for damages.
So there will be a need for a second law, blocking survivors from taking this sort of action. In short, it's gonna get messy real fast.