This document summarizes how speed cameras detect vehicle speed using Doppler radar technology. Speed cameras transmit radar signals that bounce off vehicles and return to the camera. The difference in frequency of the transmitted and returned signals, known as the Doppler effect, allows the camera to calculate the vehicle's speed. Speed cameras were introduced in the 1990s and have been shown to reduce road accidents and casualties by deterring speeding. The document discusses how Doppler radar works, the basic components and principles of speed cameras, and their effectiveness even in poor weather conditions. It stresses the importance of public awareness about how speed cameras promote road safety.