Id say Boston too. Someone had just gotten done telling me what bad drivers Bostonians were, and minutes later we saw a bizarre auto accident. What apparently happened was, some guy in a mail truck (might have been UPS or Fedex) was driving down the road, and it looked like someone parked had pulled out in front of him. He sideswiped this guy and what looked like a few other parked cars. I didnt see the whole thing, it might have been he just rammed the line of parked cars, but either way it was a pileup with only one vehicle involved that was actually being operated. Sheesh.
First, I’m shocked that Atlanta only placed 5th in the bad drivers poll, when I think Nashville, TN and Tampa, FL were horrible cities to visit, but then maybe you get used to dodging insannanuts in your own city. 
One thing about Mass…non-Boston-commuters may get freaked out on the highways if they don’t realize that the breakdown lanes around Boston are legally open to traffic during rush hour.
It’s the same way in the DC area on the beltway during rush hour and doubly so in winter. Once there is one accident, people cause more accidents around it because they are looking at the accidents that have happend already. They do this wheather or not it’s on the same side of the road or not. People are also very aggressive and do not let you merge into traffic from entrance ramps (they think-“How dare this person try to get in front of me, I was here first and I am already so late, I can’t let anyone else get in front of me”). IMHO, DC is the worst overall for stupid things happening. Although I’ve heard that Knoxville, TN is pretty bad too for people running red lights. And what gets me about Boston is drivning on the shoulders–what is up with that??
Boston drivers will drive wherever they have to in order to get ahead of you. If the road widens up they will treat it as a two-lane road to pass you. They will drive on shoulders. Thety will drive on sections that have been striped (indicating that YOU SHOULD NOT DRIVE ON IT)if they have to. I have seen them go over the grass-planted dividers to get ahead. Boston drivers, for whatever reason, are excessively pushy and aggressive, and won’t let the absence of a legal road restrict their movements.
Of course, they also have the fact that Boston doesn’t believe in marking its streets to help make them crazy. This is True, and still astonishes the out-of-towner. Most towns will only mark one of the streets at a crossroad. This makes finsding our position on a map very difficult. You know you’re on Main Street (or whatever), but you have no idea what street you’ve just crossed. So you drive one block further down and there’s only one sign, and it says “Main Street”. Massachusetts towns save 50% on street signs and gain a lot of free entertainment watching the out-of-staters get lost.
Everybody knows about Route 128. It may not e the hotbed of computer activity it once was, but it’s still as vital business road. Except none of the road signs says “Route 128”. Over most of the length of the road encircling Boston, Route 128 is coincident with Interstate 95, so all the signs direct you to I-95. Only as you’re about to get on it is there a tiny, aopologetic sign that tells you it’s also Route 128.
Add to this the fact that roads do, frequently, change their names without warning. The street our business is on has one name at one end and another name at the ther. No one seems to know at which point the street changes its name. (Both ends, by the way, are in the same town, Cambridge)
The philosophy seems to be that If you Don’t know where you’re going, You don’t Deserve to Get There.
I’ve lived and driven in Atlanta, Houston, San Diego, Athens (Georgia) and Honolulu, and the drivers on Oahu were by far the worst. They’re not rude, they’re not inconsiderate, they just don’t know what they’re doing.
…excluding Tijuana, in which the driving experience is not unlike the evacuation scenes in the film “Year of Living Dangerously,” I’d have to say Southern California in general and Hollywood and Irvine in particular…it’s like playing a video game every day. If I won the lotto here, I swear I’d buy a fleet of cheap cars and go ahead and ram all the idiot drivers not paying attention as they cruise through red lights yakking on their cellphones.
I think Tulsa has the worst drivers. I couldn’t cross the state at more than 40 mph because that the accepted speed for the fast lane of the freeway.