Where I live, I don’t see many people going 15 over. I see most people going within −3 to +9 of the speed limit. They’re following the law—maybe not strictly as written, but as socially understood. There are a few people breaking the law—and they get ticketed, etc. There are places where the speed limit is unreasonably low, and gets ignored (e.g. speed limit drops from 75 to 55 for construction zone, but no construction activity is visible), but in general, people around here follow the speed limit—as socially understood.
The social definition is that +9 is OK, and it is logically based. Speed limits are only given to the nearest 5 MPH, so arguably (not legally arguably, but in people’s heads) going 4 MPH over is not really speeding. Then, you need some kind of reasonable cushion. It defies common sense (but not the law) that a certain speed is perfectly legal in a variety of reasonable conditions, but 1 MPH faster than that is a crime. So, you have to have reasonable padding, say one 5 MPH increment. Thus, if you’re going within 9 MPH of the speed limit, you’re not speeding, just bending the speed limit, pushing into that safety margin.
Bumping a speed limit from the current value of 55 (+ social tolerance) to 65 (no tolerance) would not work. It would quickly become 65 (+ social tolerance), because you have not addressed the arbitrary nature of the speed limit. With strict enforcement, you could reduce the social tolerance value (I believe it was smaller before the 1970s national speed limit of 55 fostered widespread disrespect for speed limits), but it would difficult to eliminate it.
Where I live, I don’t see many people going 15 over. I see most people going within −3 to +9 of the speed limit. They’re following the law—maybe not strictly as written, but as socially understood. There are a few people breaking the law—and they get ticketed, etc. There are places where the speed limit is unreasonably low, and gets ignored (e.g. speed limit drops from 75 to 55 for construction zone, but no construction activity is visible), but in general, people around here follow the speed limit—as socially understood.
The social definition is that +9 is OK, and it is logically based. Speed limits are only given to the nearest 5 MPH, so arguably (not legally arguably, but in people’s heads) going 4 MPH over is not really speeding. Then, you need some kind of reasonable cushion. It defies common sense (but not the law) that a certain speed is perfectly legal in a variety of reasonable conditions, but 1 MPH faster than that is a crime. So, you have to have reasonable padding, say one 5 MPH increment. Thus, if you’re going within 9 MPH of the speed limit, you’re not speeding, just bending the speed limit, pushing into that safety margin.
Bumping a speed limit from the current value of 55 (+ social tolerance) to 65 (no tolerance) would not work. It would quickly become 65 (+ social tolerance), because you have not addressed the arbitrary nature of the speed limit. With strict enforcement, you could reduce the social tolerance value (I believe it was smaller before the 1970s national speed limit of 55 fostered widespread disrespect for speed limits), but it would difficult to eliminate it.