How does radar technology calculate the speed of a moving vehicle?

Radar technology calculates the speed of a moving vehicle primarily by using the Doppler effect. This phenomenon involves the change in frequency or wavelength of waves in relation to an observer who is moving relative to the wave source. When a radar device emits a signal towards a moving vehicle, that signal reflects back to the radar unit after hitting the vehicle. If the vehicle is moving towards the radar, the frequency of the returned signal increases, and if the vehicle is moving away, the frequency decreases.

The radar unit measures this frequency change and calculates the vehicle’s speed based on the difference between the emitted signal and the returned signal frequency. This process allows for immediate and accurate determination of speed, which is crucial for law enforcement and traffic monitoring.

In contrast, other options like measuring sound waves, analyzing color changes, or using GPS coordinates do not apply to radar technology. Sound waves operate under different principles, color changes do not provide any speed-related information, and GPS, while it can track movement, relies on satellite technology, not radar measurements.