In L.A., car is king and there are millions of them. To me, the problems are not generally from lack of knowledge or lack of skill, (these can be a problem, of course), but from the attitudes of the drivers. Street racing, texting while driving, road rage, and even drunken driving are things people know they aren't supposed to do, but they do anyway.
The number of drivers who drive in an aggressive, attacking manner is staggering. Everyone should be forced to be a pedestrian, a cyclist, and a motorcyclist to learn empathy.