Abstract: Vehicle mountable subsystems include a modified nose cone, deflecting air between the trailer and its tractor. Drag at the rear is reduced by vertical vanes at its rear corners, mounted by spring biased supports to allow opening rear doors and restoring the deflecting positions upon closing. Air from the top is deflected downwardly across the rear through a transverse upper scoop. A transverse lower scoop directs air from under the trailer upwardly across its rear surface. Both scoops are fabricated from a resilient material to allow compression against a loading dock structure. An undercarriage enclosure, fabricated into a number of longitudinal segments determined by trailer length, having side skirts and a trailer width upper panel, includes an air deflecting front surface and a channeled rear transverse surface. Flexible skirt extension panels depend toward the roadway.