There is already a motor vehicle violation that applies to situations like this . . . it's called reckless driving, and it's far more serious than simply "speeding."
I plan and design transportation systems for a living (including highways), and I can assure you that there is no truly legitimate legal basis for a jurisdiction to impose a statutory speed limit of 55 or 65 miles per hour on a highway that has been designed to safely accommodate vehicles moving at 75-85 miles per hour (under wet conditions, mind you). Sure -- a vehicle that travels at 85 miles per hour is more "dangerous" by any objective measure than one traveling at 65. But a vehicle traveling at 65 is more dangerous than one traveling at 45, 35, etc. For that matter, a vehicle traveling at 5 miles per hour represents an infinitely greater threat to public safety than one that is stationary. So let's just outlaw motor vehicles altogether, eh?
Hmm. So you're saying that if I'm just "speeding," then it's not a danger to others. But if I'm speeding a lot, then it's a danger to others such that I can be arrested or ticketed? Huh. That seems pretty similar to the concept behind DWI laws.
Sure -- a vehicle that travels at 85 miles per hour is more "dangerous" by any objective measure than one traveling at 65. But a vehicle traveling at 65 is more dangerous than one traveling at 45, 35, etc. For that matter, a vehicle traveling at 5 miles per hour represents an infinitely greater threat to public safety than one that is stationary. So let's just outlaw motor vehicles altogether, eh?
I never said that, but because the cost of determining risk in every single instance is far too high, we line draw. For the most part, our legislatures have chosen to draw the line at 65 or 70. If they choose to draw the line at 55 or 45 or even, as you suggest, 5, that is the decision of the legislature. But, in the same way that we choose to draw lines in terms of speed limits, we also choose to draw lines in terms of operating a vehicle while intoxicated--.07 sends you on your way home. .08 puts you in the pokey.
And by the way, since you want to nit pick on the violations, try this one: policeman sitting in a bar/grill having dinner. Over the course of his meal, which takes an hour, he observes a patron consume several mixed drinks; say, half a dozen. Policeman leaves and sees patron walk to his car, get in, and drive off. Fourth Amendment violation to stop the driver?