Hybrid buses highlight clean-air agenda at Yosemite

California’s Yosemite National Park took delivery in April of 18 diesel-electric hybrid buses in a move designed to reinvigorate the park’s shuttle fleet. The buses were manufactured by Hayward, Calif.-based Gillig Corp., with hybrid powertrains designed by General Motors Corp. According to the San Jose Mercury News, Yosemite’s old fleet was wearing out, with some buses reaching the 14-year mark. The U.S. National Park Service considered other options, such as clean diesel and pure electric buses, but settled on hybrid technology. GM says the hybrid system being used on Yosemite’s buses reduces certain emissions by up to 90% and offers 50% better acceleration than traditional diesel bus engines. As a bonus, park officials said the new models have improved fuel economy over existing hybrid buses in service in places such as Seattle by as much as 55%. Fuel economy is achieved by the two-mode hybrid design that relies primarily on the electric motor at low speeds and the internal combustion engine when climbing, passing or traveling at higher speeds. The buses are part of a large-scale effort to renovate the park and reduce air pollution. Early returns have been promising. “Visitor reaction has been overwhelmingly positive,” said Scott.