ISSUES IN TRUCK SIZES AND WEIGHTS--IMPROVED TRUCK SIZE AND WEIGHT LIMITS: THEIR CONTRIBUTION TO CONSERVING ENERGY OVER THE PERIOD 1975-1980

This paper estimates the gallons of diesel fuel conserved by trucks operating under modern truck size and weight regulations since January 1, 1975, when the Federal-Aid Highway Amendments Act of 1974 allowed the permissive weight limits of 20,000 pounds for single axles, 34,000 pounds for tandem axles, and a gross vehicle weight of 80,000 pounds. The paper is composed of two parts. The first part calculates the actual diesel fuel conserved by twin-trailer combinations for the period 1975-1980 as compared to the estimated savings potential during the same period. The second part estimates the diesel fuel conserved by five-axle trucks operating within states which allowed 80,000 pound gross vehicle weights on the Interstate Highway for the same year period. The paper estimates that 65-foot twin-trailers have saved over 595 million gallons of diesel fuel since 1975. Unfortunatley, 501 million gallons of potential diesel fuel savings were forfeited for the following reasons: 303.1 million gallons were lost due to restrictive truck size and weight limit states encircling liberal and midwestern states; 126.2 million gallons were lost due to the interstate effect of traffic moving west-east when restricted by the lower limits of key eastern and midwestern states; and 72.1 million gallons were lost due to the isolation of three eastern states. Assessing the impact of gross vehicle, limits the paper estimates 700 million gallons of diesel were saved by five-axle tractor semitrailer combinations operating in the 45 states which permit 80,000 pounds gross vehicle weights. Moreover above 75 percent of the 700 million gallon savings can be directly attributed to the 35 states (including the District of Columbia) which were able to increase their weight limits as a direct result of the Federal-Aid Highway Amendement Act of 1974. Ten states had weight limits at or above 80,000 pounds in 1975 under a provisions, known as the "grandfather clause", in the Federal-Aid Highway Act of 1956. (Author)

• Corporate Authors:

  American Trucking Associations

  Research and Economics Division, 1616 P Street, NW
  Washington, DC  United States  20036
• Authors:
  • KOLINS, R W
• Publication Date: 1981

Media Info

• Features: Appendices; Figures; Tables;
• Pagination: 46 p.

Subject/Index Terms

• TRT Terms: Diesel fuels; Energy conservation; Fuel consumption; Gross vehicle weight; Laws; Savings; Size; Size and weight regulations; Trucks; Trucks by weight; Weight
• Uncontrolled Terms: Increase
• Subject Areas: Energy; Environment; Highways; Law; Motor Carriers; Planning and Forecasting; Vehicles and Equipment; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 00335414
• Record Type: Publication
• Report/Paper Numbers: TSW-81-2 Tech Rpt.
• Files: TRIS
• Created Date: Jan 29 1982 12:00AM