Autonomous vehicles do of course have the potential to reduce deaths but there are lots of examples of this being the preferred method of regulation in the auto industry. For example if you want to sell a motorcycle in the US it has to have a kill switch in a specific place on the right handlebar. You don't (as a manufacturer) get to innovate about this because it's a safety feature and a first responder needs to be able to locate the kill switch so it always has to be in the same exact place so they can always find it. If you want to sell a car in Europe (I believe) it has to have seatbelts, ABS and a catalytic converter that meets a particular specification etc etc.