What technology is used to measure closing speed?

The technology used to measure closing speed is high-frequency Doppler. This technology operates by emitting a signal and analyzing the frequency of the reflected signal that comes back after bouncing off a moving object, such as a vehicle. When the object is moving towards the source of the signal, the frequency of the reflected signal increases; conversely, if the object is moving away, the frequency decreases. This change in frequency allows for precise calculations of the speed at which the objects are approaching each other, or closing speed.

High-frequency Doppler technology is particularly advantageous in speed enforcement applications because it can accurately track the speed of multiple vehicles in motion, even in heavy traffic conditions. This technology provides reliable data that is vital for law enforcement in speed detection scenarios.

Other technologies mentioned, like radar, laser range finders, and ultrasonic sensors, have their own applications and capabilities, but high-frequency Doppler is the most directly associated with measuring closing speed due to its reliance on frequency shifts caused by relative motion.