Because US roads traffic control systems suck ALSO licenses are much easier to get, there is more of a tacit tolerance of drunk driving, and the lower rate of public transport makes more people forced to drive despite preferring not to, leading to less of a selective effect of drivers.

We've consequentially paved over the issues (no pun intended) via creating a socioeconomic hierarchy of insulation from traffic injuries. Giant SUV's have become the mainstay of the upwardly mobile 30s suburbanite, who is immunized from the road hazards, collisions and dangers that would cripple sedans.