Transit Agencies Should Take Lock-in Effects into Account when Purchasing Alternative Fuel Buses.
Long-term factors can have a substantial effect on life-cycle costs for alternative fuel bus options.
Made Public Date


United States

Life cycle ownership cost and environmental externality of alternative fuel options for transit buses


Researchers used characteristics of the operations and 736-bus fleet of the Port Authority of Allegheny County (PAAC) to estimate life-cycle costs associated with several alternative fuel options for transit buses. The analysis considered the following variations for a 40-foot and a 60-foot transit bus:

  • Conventional bus powered by either diesel or a biodiesel blend (B20 or B100) 
  • Diesel hybrid-electric bus
  • Sparking-ignition bus powered by Compressed Natural Gas (CNG) or Liquefied Natural Gas (LNG) 
  • Battery electric bus (BEB) (rapid or slow charging)

Estimates were made for life cycle ownership that included costs for buses and infrastructure, and costs associated with environmental externalities attributable to greenhouse gases (GHGs) and criteria air pollutants (CAPs) emitted during the life cycle of bus operation. Two funding scenarios were modeled: a common 80 percent external / 20 percent local; and a 100 percent agency funded scenario.

Lessons Learned

  • Some alternative fuel options, such as CNG, LNG, and BEBs, have strong lock-in effects due to the refueling or charging infrastructure required.
  • Agencies that operate BEBs should be prepared to adjust to changes in planning and scheduling due to differences in range and charging. Rapid-charging BEBs may be more feasible on routes operating on dedicated right-of-ways that have consistent running times. 
  • A transit agency is unlikely to be able to operate more than one alternative fuel option due to limited financial, human, and land resources.

Researchers recommend that transit agencies carefully consider both short and long-term perspectives when selecting buses for purchase.