Retractable air deflection apparatus for reduction of vehicular air drag

A drag reduction apparatus for the rear end of a cargo-carrying compartment of a cargo-hauling ground vehicle, said cargo-carrying compartment being characterized by a rear wall formed by substantially planar wall portions arranged above, below and on opposite sides of an opening with at least one door disposed therein, the drag reduction apparatus comprising two non-planar air deflection elements and a plurality of support members associated with each said air deflection element and coupling each said air deflection element to a respective associated portion of the exterior surface of said vehicle that is adjacent and substantially orthogonal to said rear wall, each said air deflection element having a leading edge and a trailing edge, said plurality of associated support members allowing selective displacement of each said air deflection element between a retracted position and at least one deployed position, said at least one deployed position comprising at least a first deployed position and a second deployed position, wherein in said retracted position the leading edge of each said air deflection element is substantially flush with said respective associated portion of said exterior surface and the trailing edge of each said air deflection element substantially abuts said respective associated portion of said exterior surface, and wherein said two air deflection elements comprise the left-side air deflection element and the right-side air deflection element for said vehicle.