Abstract: In a vehicle, especially a utility vehicle, aerodynamically acting device for reducing the aerodynamic resistance are provided at the corners between the side panel and roof and at the corners between the side panel and rear end. The flow around the edge between the side wall and roof, especially under side wind conditions, is optimized by means of a bent roof surface (7). At the rear end, the side panel and the roof surface are also bent (7) in a form that tapers the flow around them. For further resistance reduction, blowout openings (8) are provided on the edges of the rear end, by way of which openings either back pressure air from the relative wind or pressurized air from the fan is blown out obliquely to the center axis of the vehicle, so that the static pressure of the rear-end surface is relatively increased and the aerodynamic resistance is reduced thereby.

Abstract: A device for reducing the aerodynamic resistance of a moving commercial vehicle includes an inflatable air bladder element which carries at least one rigid spoiler element. The inflatable air bladder element is in a deflated condition when the vehicle is at rest, and is brought into an inflated condition by dynamic pressure of air flow in response to forward vehicle movement. The spoiler element is deployed in response to the inflatable air bladder element assuming its inflated condition so that it moves from a position substantially parallel to the rear end of the vehicle, to a deployed position in which it extends angularly with respect to the vehicle. In such a manner, the spoiler element improves the dimensional stability of the device.