The interesting thing is that Maryland drivers are among the worst I've seen over a wider spectrum of factors. Sober California drivers seem pretty safe. Virginia drivers are miserable on interstates because they pass one another at 1-3mph differentials (I assume this is a response to the reputed harsh soeeding enforcement there) and are victims of often-wrong signage, but are otherwise uninteresting. South Carolina drivers cause dangerous situations by trying to give away their right of way. Maryland drivers aggressively fight back agaibst merges, change lanes erratically, and crash in a quarter inch of snow at shocking rates, despite the fact that their salt trucks have higher mass-flow-rates than their snow storms. The only drivers who stand out vs Maryland are in big military areas where there's a significant minority of people driving 20mph faster than traffic and merging erratically while doing so.
Having just left VA after a year in residence, VA drivers pass at 1-3mph deltas because they're already doing 15mph+ over the speed limit. Perhaps enforcement is different in southern VA, but I'd estimate only seeing speed traps/vehicles pulled over once every 3-4 weeks.
Maryland (and, to a lesser degree, New Jersey) drivers are legitimately terrible whenever you find them.