In LIDAR, the Cosine effect is in whose favor?

The Cosine effect in LIDAR refers to how the angle of incidence of the LIDAR beam can affect the measurement of distance to a target. When an object, such as a vehicle, is approaching the LIDAR device at a very shallow angle, the reflected signal can be weaker, and the device may underestimate the speed of that object. This effect can favor motorists because it can lead to an inaccurate speed reading, potentially resulting in lower speed estimates than are actually true.

In practical terms, if a motorist is traveling fast but is detected at a shallow angle, the speed calculated by the LIDAR may not reflect the true speed. This phenomenon means that motor vehicles approaching the LIDAR device at a slight angle might avoid getting flagged for speeding, benefiting them compared to other road users like pedestrians or cyclists, who may be measured more accurately due to their typical angles of movement.

Other groups, like law enforcement and pedestrians, do not benefit in the same way from the Cosine effect. Law enforcement relies on accurate measurements for speed enforcement, while pedestrians and cyclists typically do not encounter situations where their speeds would be misrepresented in the same context as motorists. Hence, the Cosine effect ultimately favors motorists.