Which technology is less effective in measuring speed when several vehicles are in close proximity?

Radar technology is less effective in measuring speed when several vehicles are in close proximity due to its method of operation. Radar uses radio waves that can bounce off multiple objects, which causes difficulty in accurately determining the speed of a target vehicle. When multiple vehicles are present, the radar may pick up the signals from more than one of them, leading to misleading speed readings or maximum speed capture of the closest vehicle rather than the target intended for measurement.

In contrast, Lidar utilizes light pulses and has a more focused beam. It allows for better differentiation between vehicles that are close together, as it can measure distances and speeds with higher precision. This ability to narrowly target specific vehicles lends itself to more accurate speed enforcement, particularly in densely populated areas with multiple vehicles.

In this scenario, while both technologies have their uses, radar's broader signal and difficulty in distinguishing individual vehicles make it less effective in situations where numerous vehicles are nearby.