I've lived in Boston, Jacksonville, and Miami and i think you're right on point. Miami has a special intersection (pun!) of retirees, newer immigrants, tourists, and young people (not saying any of these groups are bad drivers as a rule, but they certainly have a wide array of driving styles); combined with poor infrastructure design it's a deadly mix. I have friends who've moved from Miami to LA, and they all agree the traffic in South Florida is worse.
