THE ENERGY AND ENVIRONMENTAL CONSEQUENCES OF INCREASED VEHICLE SIZE AND WEIGHT. VOLUME I

The study objectives are to determine whether increased size and weight vehicles would be energy efficient and cost effective and to investigate operational and environmental consequences resulting from their use. Not all the objectives were obtained since only Phase I of a proposed two-phase study was completed, and lack of data restricted work in cost responsibility, safety and bridges. Findings include (1) non-uniformity in size and weight regulations between states which creates artificial barriers to economic truck operation, (2) increasing axle loads by 33 percent could reduce pavement surface life by 80 percent unless thickness is increased by 2 1/2 inches, (3) further work is needed to define the effect of heavier trucks on bridges, (4) the effect of larger, heavier trucks on the traffic stream can be quantified using a computer program developed in the study, (5) the data base for safety effects is inadequate, (6) operating costs are less for heavier, larger trucks, (7) environmental effects appear to be less significant than effects on bridges, etc., (8) incremental fuel requirements for different size and weight trucks can be quantified while assessment of energy requirements for highway construction and maintenance needs further work and (9) considerable additional work is needed to define how the costs and benefits attributed to vehicles of various sizes are distributed to impacted or benefitting groups.