Earlier quoted context omitted.
The other day, I came within two feet of a crash because the other driver completely disregarded a red light. It's pretty clear that if a human can't even pay attention to a light directly pointed at them, we have a very long time to go before humans can safely drive cars without a computer to intervene when needed.
One thing worth mentioning (even though I agree with the gist of your point) is that machines make the same mistakes consistently. This is pretty rare for a human. Imagine 10% of the cars on the road are autonomous and they all make this same mistake.
Of course, the road system is designed for humans' foibles, not computers' foibles, and computers will have to deal with that. But the bar is low.
Computers aren't really as consistent as you say, either. Obviously, a deterministic machine will produce the same outputs for the same inputs. But when your inputs are camera data from the real world, you'll never get the same input twice. For example, my car sometimes misreads or fails to read speed limit signs, but it'll usually read the exact same sign perfectly fine the next time I go past.