Speeding in New England

Rory Blyth has a good rant about speeding in New England. As the comments show, its not unique to New England -- San Diego, especially, I find amazing that an urban freeway has a speed limit of 70, heavy traffic and curves, and average speed of 85+.

So why are some areas so speed limit tolerant? Virginia Beach, Virginia has excellent interstates where driving 65 is unusual (and without a high cop presence -- speed traps have an obvious effect on behavior). Charleston, SC is pretty slow. North Carolina has some fast drivers but is mostly slow. Yet go to San Diego, Boston suburbs, or Orlando, and its pretty close to the Indy 500.