A Wheel Speed Sensor is a device used in vehicles to monitor the speed of each wheel. It provides real-time data to the vehicle's anti-lock braking system (ABS) and traction control system, helping to enhance safety and performance. By detecting the rotational speed of the wheels, the sensor can identify issues like wheel slippage or locking. These sensors typically use magnetic or optical technology to measure wheel speed. When a wheel spins, the sensor generates a signal that is sent to the vehicle's computer. This information is crucial for adjusting braking force and maintaining vehicle stability during various driving conditions.