What is the safety record for semi-autonomous cars per mile driven? I worry that even if it's better than human piloted vehicles, progress could be short-circu

What is the safety record for semi-autonomous cars per mile driven? I worry that even if it's better than human piloted vehicles, progress could be short-circuited by the fact that since this is a novel technology, it makes the news every time an accident occurs. On the other hand, while it seems that we're on the cusp of an autonomous vehicle revolution, and we'll see commercial use adopting early, consumers are going to be wary. The failure modes are very different than what drivers are used to. The systems appear "dumb" and make mistakes that humans rarely do. I see more promise in the short term for collision avoidance systems, or other systems which augment the driver's ability. For example anti-lock brakes have been an almost complete win, almost to the point of invisible ubiquity. I'd love to have something on-board my car that can help me safely avoid hitting a deer at 75mph.