Efficiency characteristics of tractor-semitrailers

Tractor-semitrailer is the most common truck configuration in many countries accounting for more than 70% of truck traffic in North America. The types and number available are dictated by the regulatory setting of the particular jurisdiction. This paper presents the efficiency characteristics of some tractor-semitrailertrucks with five or more axles using a proposed concept of efficiency measure. The relative efficiencies are measured in tenns of the productivity, infrastrUctUre impacts, vehicle stability and control characteristics. It is shown that the six-axle tractor­ semitrailer with close-spaced tridem axle unit on the semitrailer is the most efficient truck among those investigated. The semitrailer with a belly single axle is less efficient compared to one with close-spaced tridem in terms of both dynamic and operational performance. Using wide spaced single axles on the semitrailer to maximize payload , does not improve operational efficiency and stability and control properties.