ISTR that turnpike highways in the eastern U.S. simply record when cars reach each tollbooth. If a car arrives too soon at a booth, the driver is automatically fined for driving too fast. Can anybody confirm this?
NH has a lot of troopers on their highways, you really can't drive far without seeing several. In MA, I rarely see MSP troopers on the highways (aside from the one taking a nap in the middle of the cloverleaf on a big interchanges during the early evening commute when the traffic is crawling).
Driving through the NYC/NJ/Baltimore/DC I95 corridor, there's a lot of tolling going on, express lanes etc but I've never had a ticket despite averaging 10 over driving through at night.
FL has lots of tolling going on, but I can't say I've ever seen a FL trooper on patrol, usually only at the scene of an accident/breakdown.