There's also a significant tort issue. Consider the case where a drunk driver kills himself and someone else. Now consider the case where an autonomous vehicle kills its passenger and the passenger in another car.

A jury needs to award damages against A) the grieving widow of the drunk driver or B) A large corporation. I suspect the latter will be at least an order of magnitude higher. This means that until autonomous vehicles are an order of magnitude safer, the car companies will have to absorb more damages than the sum of what all of their customers would have.