The surface transportation assistance act of 1982 permitted the use of twin trailer trucks and semitrailers 48 feet long and 102 inches wide on most major us roads with the intention of increasing theefficiency of freight transport. A controversial move, provision was built into the act for the national academy of sciences to monitorits effects with particular regard to safety. The results are presented of an examination carried out by the committee set up to study all aspects of the impact of new truck sizes. The history of truck size and weight regulations and the debate surrounding the 1982 act are outlined. Three major areas of impact are identified and examinedin detail - trucking costs, safety and the impact on highway conditions, operations and design. In each area past experience is reviewed, evidence from the monitoring programme assessed and a projection made of the probable magnitude of the effects nationally and regionally. Recommendations are made for future data collection, improvements in truck safety and continuation of the study.
Abstract