A drag reducing device for a vehicle includes an air flow turning component having a curved surface adapted to turn air flow passing over the curved surface, a first mounting component for connecting the air flow turning component to a rear door of the vehicle, and a second mounting component for connecting the air flow turning component to one of the opposite side walls of the vehicle. The mounting components are configured so that the air flow component is automatically in a deployed position when the rear door is closed, in which position the air flow turning component turns air flow passing along the side the vehicle inward to thereby reduce drag. The mounting components are further configured so that the air flow component is automatically stowed between the rear door and the vehicle side wall when the door is fully opened. The air turning component is an extrusion sized for a minimal prominence in the stowed position.