The only emissions fuel cells produce are heat and water. Toyota and Honda both sell hybrid gasoline-electric cars in the United States. But while every U.S. automaker has a hybrid project in development, none has yet been brought to market. The amount of money Detroit puts into hybrid research and development and the speed with which they bring these cars to market will depend upon consumer demand. Again, many advanced technology vehicles are already available for use by fleets with the ability to refuel and maintain them.
Some automakers tout diesel fuels as the way to improve efficiency and prevent global warming.
But reliance on diesels comes at the unacceptable price of human health and clean air. Diesel particulate exhaust has been declared a carcinogen by the World Health Organization, the National Institute for Occupational Safety and Health, and the California Air Resources Board. Diesel engines account for approximately 26 percent of the total hazardous particulate pollution in the air, and 66 percent of particulate pollution from motor vehicles. Particulates are linked to increased asthma emergencies and to thousands of premature deaths in the United States every year. Diesel vehicles also emit high amounts of nitrogen oxides, a major component of smog and acid rain.