During the late 1970's and early 1980's considerable effort was expended in the improvement of truck aerodynamics to reduce fuel consumption. This first-generation effort focused on aerodynamic drag reduction obtained from add-on aerodynamic aids to the cab or the trailer, from improved cab shaping and from body/trailer front-end edge rounding.
Rising fuel prices have renewed interest in further aerodynamic improvements. This paper will review past developments and show that several unused concepts offer potential as second-generation, add-on, fuel-saving technology. It will raise the issue of finding successful means for bringing them profitably into service, which will require concerted action by the trucking industry, manufacturers and government.