Vascar?

[predator20]

I look for a better shot of the vascar unit.

VASCAR (Visual Average Speed Computer And Recorder) is a technology for determining the speed of a moving vehicle. It is used by police officers to catch speeders, mainly in jurisductions where RADAR and/or LIDAR are illegal, or to prevent detection by those with radar detectors. A VASCAR unit couples a stopwatch with a simple computer. Speed calculation is done by dividing the distance between two markers (such as a white circle or square painted on the carriageway) by the time the target vehicle takes to travel between the markers.

This also allows determination of vehicle speeds by aerial platforms, such as helicopters, making it easier to make a conviction.