Comment by fiddlerwoaroof

The Cayenne would not be safer going 35 instead of 40 "regardless of all other variables": it's statistically safer to go closer to the flow of traffic because you're then "at rest" with respect to other drivers (assuming a controlled access road without pedestrian traffic). If the speed limit is 55 and the flow of traffic is 70–80 (as is the case with the Beltway around DC, despite automated enforcement), then going 55 is more dangerous than "speeding". The issue with 100% enforcement is every law assumes certain circumstances or variables and the real world is infinitely more complex than any set of variables that can reasonably be foreseen by law (and laws that attempt to foresee as many variables as possible are more complicated and, consequently, harder for normal people to apply, which is another reason for latitude in enforcement).