[ryaldin]

In montana, the speed limit used to be defined as "reasonable and prudent", about five years ago. Unfortunately, the Supreme court ruled it unconstitutional, and therefore, we have typical federal speed limits for interstates at 75 (you can usually get away with about 80) and highway speed limits set to 70 (and the standard buffer of 5 mph is applicable here as well).

Reasonable and Prudent, was of course, open to interpretation, so people who had been driving for 20 years, with no speeding tickets, no accidents, a fast car, completely updated and with the proper equipment to handle such speeds (tires, suspension, etc.) could reasonably expect to get away with 120 mph with the police right there. BUT, if your a pimply teenager who's had his licensce for four and a half months, and you own a 1984 toyota cressida, with rusted paneling and bald tires, a cracked windshield and you don't use you blinker, you couldn't really expect to get away with much over 80. It was a reasonable rule, but oh well.