Assessment of Hybrid-Electric Transit Bus Technology

TRC's research team did analysis to determine whether compressed natural gas (CNG) or hybrid-electric bus (HEB) technology is more economically and environmentally efficient. The researchers developed a comprehensive bus life cycle cost model (LCCM) to evaluate HEB performance, taking into account both purchase price and operating costs. In the LCCM, 5 different bus technologies were tested in New York, NY; Seattle, WA; Long Beach, CA; and Washington, D.C. The technologies compared were pre-2007 diesel, conventional diesel, diesel hybrid-electric, gasoline hybrid-electric, and CNG buses. Analysis confirms that the HEB purchase was more expensive than the purchase of diesel or natural gas buses, but HEB offer superior fuel efficiency, particularly at low speed. HEB can increase fuel efficiency and reduce tailpipe emissions significantly for the transit fleet.