I worked as city PD in Montana for 10 years before going federal. As you would enter town from the west, you would come down from an overpass going from 55 to 35 it was common for drivers to maintain their speed for nearly a mile before slowing down. Generally, we would not cite for speed unless they were more than 1/4 mile past the 35 sign.
I stopped a driver doing 60, 1/2 mile beyond the 35 mph sign, and being a smart ass, When I approached the driver I said "OK Sky King, let's see your pilots license" The driver looked at me with a quizical expression and handed me his BRAND NEW PILOTS LICENSE that he had just recieved. He was on his way home and so excited about getting it he was not paying attention.
All I could do was congraulate him, ask for closer attention to speed and send him on his way. The lesson here was for me.