Vehicle Speed Enforcement Using Absolute Speed Handheld Lidar

Commonly used handheld Lidars for traffic speed enforcement measure relative speed and not absolute speed. The underreporting of the actual vehicle speeds, called the cosine effect, provides offending drivers an inordinate amount of benefit of doubt, thereby increasing the propensity of aggressive drivers aware of this limitation to push farther above the speed limit. This paper presents two approaches to augment these devices by calculating the absolute speed. The manual mode approach uses an additional intermediate measurement and geometric calculation, whereas the automatic mode makes use of MEMS sensor(s) to calculate the tangential velocity component as an intermediate step. The goal is to provide traffic speed enforcers tools that ultimately lead to safer roadways. This can be applied to other motorized transport scenarios as well.