I assume by 'southern neighbors', you are referring to M*ssholechusetts and Rhode Island; recently ranked as the #1 and #2 worst drivers in the nation (although I listed them backwards, RI was #1). I spend a lot of time on the road, and whole-heartedly agree...those idiots should have their cars confiscated.
Dirty South? I concur with regards to the amount of trash on the side of any road that wasn't an Interstate.
Bingo with regards to the Massholes and Rude Islanders.
As for the Dirty South it's a civil war expression that has seen a resurrection in recent years due to gangsta rap. I was in the Army so I know about that stuff.