The federal Clean Air Act Amendments of 1990 and the Energy Policy Act of 1992, along with other state regulations, have stimulated or mandated the use of alternative fuels to power transit system bus fleets. Among such fuels, compressed natural gas (CNG) is attractive, even though it must be stored in robust, pressurized cylinders capable of withstanding pressures up to 34,450 kPa (5,000 psi). Such systems are typically heavier than conventional diesel storage tanks. As a result, gross vehicle weight is raised, sometimes significantly, which then increases the consumption of the pavement over which CNG buses operate. Capital Metro, the Austin, Texas, transit authority, is evaluating a number of CNG-fueled buses. As part of the U.S. Department of Transportation's University Transportation Centers Program, the scale of incremental pavement consumption associated with the operation of these buses was studied. The study suggests that replacing current vehicles with CNG-powered models using aluminum storage tanks would raise average network equivalent single-axle impacts by about 6%, which means an increase in total overlay rehabilitation costs across the network of more than 4% a year. Finally, it recommends that a full cost study be undertaken to evaluate the adoption of alternative bus fuels, including its pavement and environmental impacts.


  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 20-25
  • Monograph Title: Environmental issues: energy, water, noise, waste, and natural resources
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00711758
  • Record Type: Publication
  • ISBN: 030906113X
  • Files: TRIS, TRB, ATRI
  • Created Date: Sep 18 1995 12:00AM