Hand-held radar is the original "gun" speed trap. The older "analogue" designs were limited in features. Newer Radar Guns utilizing "Digital Signal Processing" are superior in discriminating amongst several vehicles in the "target zone".
In most states of Australia, hand-held Laser is preferred by Police departments. This is due to the very narrow beam that can isolate a single vehicle in dense traffic. On country roads, where traffic is not congested, Radar Speed-Guns are effective, stationary speed checking devices. Their robust construction suggests less frequent calibration and a longer service life.