BMW X3 Owners Manual: The concept

HDC is a downhill driving assistant that automatically controls vehicle speed on steep downhill gradients. Without applying the brakes, the vehicle moves at slightly more than walking speed.

Hill Descent Control can be activated at speeds below approx. 22 mph/35 km/h. When driving downhill, the vehicle reduces its speed to approx. walking speed and then keeps its speed constant.

As long as there is active braking, the system is on standby. The system does not brake the vehicle during this time.

Only use HDC in low gears or in selector lever position D or R.