Wheel Speed

• These are the sensors positioned in the wheel to determine the wheel's rotation speed. They are also called wheel speed sensors.
  
  

Anti-Lock Brake System

• One of the purposes of the wheel speed sensor is to deliver data to the anti-lock brake system. In case of an emergency when one of the wheels will lock up, the ABS rotates the wheels appropriately. This can be felt as a pulsing action.
  
  

Traction Control System

• The traction control system also takes data from the wheel speed sensors but uses it to keep control of the vehicle on the road when excess throttle is applied. This has been an important feature in high performance vehicles.
  
  

Crankshaft Speed

• The crankshaft speed sensor indicates how fast the crankshaft spins. It determines how fast the vehicle is traveling.
  
  

Speedometer

• The speedometer is the gauge in the dashboard which takes information from the crankshaft speed sensor and displays it as a miles-per-hour or kilometers-per-hour.