If the speed driven and the target speed differ, and you activate DSR on a slippery road surface, the wheels may lose traction.
If you fail to adapt your driving style, DSR can neither reduce the risk of an accident nor override the laws of physics. It cannot take into account road, weather or traffic conditions. DSR is only an aid. You are responsible for maintaining a safe distance to the vehicle in front, for vehicle speed, for braking in good time and for staying in lane.
You are always responsible for keeping control of the vehicle and for assessing whether the downhill gradient can be managed. Depending on road surface and tyres, DSR may not always be able to keep to the target speed. Select a target speed suitable for the environmental conditions and also apply the brakes yourself if required.