Washington (DC) Metro has purchased 28 diesel-electric hybrid buses manufactured by New Flyer, and using the GM-Allison parallel hybrid powertrain, and has agreed to buy 22 more, for a total of 50.
Not including the Metro order, there are some 364 GM hybrid-equipped buses operating in 25 cities across the US and Canada. The majority of those buses are in Seattle, which accounts for 237. With its order of 50 hybrids, Washington will represent the second largest deployment of GM hybrids.
When going through the selection process, we reviewed various types of alternative fuel and hybrid propulsion systems for buses. The decision to go with the GM hybrid system was based on its proven use in other transit systems, and the overall benefits that the system will provide Metro and its passengers.—Jack Requa, chief operating officer for Metrobus
Some operational and test results from metro fleets are emerging that challenge the promised benefits of parallel-hybrids. Seattle (with the largest parallel-hybrid fleet) has reported that the hybrids fall well short of the expected gains in fuel economy, although they exceed expectations in emissions reductions. (Earlier post.) A UConn study found that while GM hybrids used by CTTransit delivered some 10%–15% improvement in fuel economy, there was no reduction in PM emissions compared to baseline diesel transit buses. (Earlier post.)