Hill Descent Control (HDC)

The Hill Descent Control is an electronic safety device that controls and regulates the speed of a vehicle when it is going downhill. The first HDC system was developed by Bosch for Land Rover. Once the HDC button is switched on the vehicle will maintain a set speed of about 7 km/h without any driver input while driving downhill. The driver can of course speed up or slow down the vehicle with the throttle pedal or brake pedal respectively. Once the driver lets go of the pedals the vehicle will again fall back to the HDC set speed. 

Hill Descent Control works in sync with the vehicle’s Anti-lock Braking System (ABS) and Traction Control System (TCS) to ensure that no individual wheel loses traction on loose or slippery surfaces and prevents the wheels from locking if you jam the brakes. HDC allows the driver to only concentrate on steering the vehicle while driving down a tricky steep downhill slope. 

HDC goes into fade out mode once the vehicle stops descending the slope giving the driver enough time to take control of the vehicle again. When HDC is on if the driver exceeds 60 km/h the on board computer automatically deactivates the HDC function. The Cruise Control controls can also be used to control the speed of the vehicle while driving downhill with HDC activated.