Most police forces us three different ways to catch speeding vehicles
Laser Radar Speed Enforcement
The officer has a hand held or laser radar on a tripod in a stationary set up with one or more police officers standing or parked on the side of the roadway.
The laser radar can catch drivers up to about one (1) Kilometer away
The officer has a hand held or radar mounted within the police car.
Depending upon the type of radar the officer can either use it in a stationary mode or while the police vehicle is moving.
Pacing Moving Vehicles
The officer uses there police vehicle to follow the vehicle and record it’s speed.
The speed recorded does not have to be 100 percent accurate but reasonable.