Prince Frederick, Maryland Speed Traps
Route 4 in Calvert County is aggressively patrolled along its entire length, with many speed traps that change location very frequently, by both county sheriffs and state police. The number of traps and patrolling cars, with and without radar, marked and unmarked cars including vans etc., is greater per mile than anywhere I have seen in almost 6 decades of driving all over the USA. Generally you can exceed the limit by 10 or even 15 mph, but not always.
Got a ticket from a cop running a trap on PF Blvd right after the light at Dares Beach heading toward 231. He sits so you can’t see him before you come around the curve and its too late. I think this one might be rare though, because I’ve only seen it once.