What is the Doppler effect in relation to speed detection?

The Doppler effect refers to the change in frequency of waves, such as sound or electromagnetic waves, as they move relative to an observer. In the context of speed detection, this phenomenon allows law enforcement agencies and speed detection equipment to determine the speed of moving vehicles. When a vehicle approaches, the frequency of the sound waves it emits increases, resulting in a higher pitch. Conversely, as it moves away, the frequency decreases, leading to a lower pitch.

Devices like radar guns utilize this principle by emitting radio waves that reflect off a moving vehicle. The frequency of the reflected waves is compared to the frequency of the emitted waves. By calculating the difference between these frequencies, the speed of the vehicle can be accurately determined. This application of the Doppler effect is crucial for effective speed enforcement in various scenarios.