In New England AFAIK, the speed limit is never over 65mph. (Andrew may know of higher spots in Maine. :-)) I generally cruise between 75 and 79, and I get passed by many cars. I have gone through radar traps at 79 many times. The fastest traffic that I have encountered anywhere in the country is between Manchester NH and Boston on I93. Of course, I generally only drive East of Illinois and in California.

OTOH, here in Mass., we have many built-in speed traps on lower roads. Mass. does not use those signs that say "Speed limit reduced ahead.", so you'll be cruising in a 55 zone and suddenly there's a sign for 40. I got bagged just beyond one of thse signs in the Western end of the state. Being semi-retired, I took a day off to go fight it and won. However, had I lost, I was told that it would cost me approsimately $500 in addition to the fine! Not having been bagged for many years, I get a good driver discount of about $100 on my insurance. I would have lost that for five years.