If your point is that highways are easier for L2/L3 but harder for L4, that makes some sense. The metric should probably be at-fault fatalities, not all fatalities; hitting a wrong-way freeway driver is hard to blame on the right-way car. Crazy stuff happens on city streets too though, and latency / reaction time is MUCH faster for the FSD computer than a human, so even highway speed is probably not the limiting factor. Granted we are not there yet; my Model Y on FSD v12.3.3 / v11 (HW3) recently ran over a
5-gallon paint bucket on the highway (fortunately empty, no damage) when I took my eyes off the road for a split second. But this is solvable, I think, and far easier than many city-streets scenarios. I expect the E2E highway stack to make tremendous improvements over v11 here.