It’s just LA. Having lived there and many other places, my hypothesis is that unlike the rest of the country, which was built around and reflecting natural geography, and so has, you know, dead-mans-curves and bad weather, LA is a big flat 8-lane-road grid, and since it’s all pretty flat, there are few places where one can actually, say, take a sharp turn and perish due to poor driving habits. People aren’t challenged by LA the way they are by, say, Boston or Pittsburgh, so stupid people survive long enough to be TOTALLY FRIGHTENED AND CRAZED by rain, because it is so uncommon. In the rest of the country, such drivers either a) die or b) get much better at driving very fast. Hence LA being seemingly populated by driving morons.