Under the U.S. SmartWay Transport Partnership  Technology Program, aerodynamic trailer technologies are verified for their fuel-saving potential.  Included are trailer boat tails with an estimated fuel savings of 1% or more; trailer side skirts with estimated fuel savings of 4% or greater; and advanced trailer end fairings and advanced trailer skirts, each with estimated fuel savings of 5% or more. Five years of fuel-economy evaluations of trailer side skirt and undercarriage ...