I think it's very clear that we /could/ engineer an automotive system that is much safe, even without self-driving tech, by modeling it on the aviation system: much more rigorous licensing requirements, certifications based on vehicle type, third-party traffic control, filing "drive plans", obsessive focus on reliability and safety. It would look a lot different from the current system, and there is no political will to get there, but the thought experiment shows that we /could/ prevent most car accidents.