The world's major automakers are tempering their enthusiasm for hydrogen-powered fuel cells to solve the environmental and geopolitical problems caused by dependence on gasoline. Instead, as a three-day "green car" conference sponsored by French tire maker Michelin Group wrapped up Sept. 26, representatives of the major automakers said redesigned diesel engines, hybrid gas-electric cars and several alternative fuels would be the short-term answer to reducing emissions and cutting gasoline use, according to the Los Angeles Times. "No one has a silver bullet that will cure everything," said David Hermance, executive engineer for environmental engineering at the Toyota Motor Co. research and development unit in Torrance, Calif., according to the Times. Automakers have been trying numerous possibilities, including cleaner-burning gasoline engines; hybrids, which Toyota and Honda Motor Co. already have on the market; various diesels designed by European automakers; and battery-powered vehicles, according to the Times.