There are some cases where we want amazing drivers, for example ambulances. But for an ordinary day to day commute, people shouldn't have to be at the top of th

There are some cases where we want amazing drivers, for example ambulances. But for an ordinary day to day commute, people shouldn't have to be at the top of their game. I think your point boils down to variance. Human drivers have a high variance, we all can be very good or very bad somewhat randomly. Your point about research is really interesting. I think a large majority of cars actually following the speed limit, looking before changing lanes, and using turn signals will have a positive effect on overall safety, even if they aren't anywhere near as good at dealing with extraordinary situations. It would be nice to know what % of "good drivers" is required to minimize those extraordinary situations, if any at all. We've all seen that one car weaving in and out of traffic. Perhaps they do indeed make us safer because they force us to pay attention. But they do seem to create a whole bunch of extraordinary situations for dozens or hundreds of drivers to deal with. It only takes the one weak driver (i'm assuming weaker than self driving here) to panic and then the freeway is a parking lot for an hour. That research would be interesting.