An apparatus for reducing the drag on a moving vehicle includes combinations of a movable diverter with a corresponding fixed diverter. Each combination is adapted to be mounted the rear of a vehicle with the fixed diverter positioned forward of the movable diverter. The movable diverter has a retracted position and an extended position and is biased to the retracted position. The movable diverter deploys to the extended position when moving above a predetermined velocity and returns to the retracted position when moving below the predetermined velocity. The movable diverter in the extended position having the rear end extending over the rear of a vehicle to direct air thereto.