Actually, the majority of auto accidents are the result of operator error. I agree we've engineered today's cars pretty well; not so much the hundreds of thousands of older ones still on the road. Traffic engineering? Sure, more limited access, divided highways. But the weak link is still behind the wheel. Driver education in the USA, IMHO, is a joke. Driver behavior in most places ditto.
Solution - don't have one. People seem to think it's their right to drive stupid and if you or I suffer for it, too bad.