The worst drivers (IMO) are in Orlando, FL and Ann Arbor, MI. That's just in the U.S. though, in their native habitat, South Koreans can't drive worth a ****.
It's so bad in S Korea, actually, that the tow trucks wait on the side of the highway. In my 7 months of living over there, I never once saw a car accident on a Korean highway that DIDN'T involve AT LEAST 5 cars. I swear, they drive like it's Fast and the Furious or something, except they all drive ****ty cars.