OT, but does anyone know what the shape of the curve for the number of automobile crashes per human driver? Is it uniform distribution, where everyone is more or less likely to get into, say, 1.2 fender-benders per lifetime? Or there is a cluster of people who are much more likely to be involved in crashes? I suppose automobile insurance companies would have this type of information.
I'm willing to bet it's the latter. There's a reason your premiums go up after you get into an accident. Insurance companies are betting that you are going to have more of them.
It's more complicated than just "good drivers" and "bad drivers". Your driving performance is very different on minute 10 of a trip vs minute 600, or 11am vs 11pm, or happy vs having a bad day. You're also very likely to be in very different environments at all of these times, and have different familiarities.
Insurance risk estimates are practical simplifications instead of trying to model how risky an individual driver is on a particular day at a particular time, in a particular area. Waymo's results are trying to compare to a statistically average driver with all other variables controlled.
It is very much the latter. It is like the statistics of average alcohol consumption: half the people consume none, and that one guy drinks non-stop. In fact, the drinking guy and the crashing guy might be the same guy.
