See also:

Remove attached parts following use
Remove unneeded auxiliary mirrors, roof or rear luggage racks after use. Attached parts on the vehicle impair the aerodynamics and increase the fuel consumption. ...

The concept
The system is functional at speeds beginning at approx. 20 mph/30 km/h. It maintains the speed that was set using the control elements on the steering wheel. The system brakes on downhill gradie ...

Remove attached parts following use
Remove auxiliary mirrors, roof or rear luggage racks which are no longer required following use. Attached parts on the vehicle impair the aerodynamics and increase the fuel consumption. ...