Public transit automobiles

Transportation accounts for about one-fourth of the primary energy consumption in the United States. And unlike other sectors of the economy that can easily switch to cleaner natural gas or electricity, automobiles, trucks, nonroad vehicles, and buses are powered by internal-combustion engines burning petroleum products that produce carbon dioxide, carbon monoxide, nitrogen oxides, and hydrocarbons. Efforts are under way to accelerate the introduction of electric, fuel-cell, and hybrid (electric and fuel) vehicles to replace sonic of these vehicles in both the retail marketplace and in commercial, government, public transit, and private fleets. These vehicles dramatically reduce harmful pollutants and reduce carbon dioxide emissions by as much as 50 percent or more compared to gasoline-powered vehicles. 

Average Energy Intensity and Occupancy Rates for U.S. Public Transit Buses and Passenger Automobiles, 1970-1997. SOURCE Davis, 1999. 

There has been an accelerated interest in polymer electrolyte fuel cells within the last few years, which has led to improvements in both cost and performance. Development has reached the point where motive power applications appear achievable at an acceptable cost for commercial markets. Noticeable accomplishments in the technology, which have been published, have been made at Ballard Power Systems. PEFC operation at ambient pressure has been validated for over 25,000 hours with a six-cell stack without forced air flow, humidification, or active cooling (17). Complete fuel cell systems have been demonstrated for a number of transportation applications including public transit buses and passenger automobiles. Recent development has focused on cost reduction and high volume manufacture for the catalyst, membranes, and bipolar plates. 

Public transit systems have been a critical part of major cities for the last few centuries. With the development and mass production of the automobile, particularly since the 1950 s, there were predictions that mass transit would be sharply reduced or would disappear completely. Cars, it was believed, would become the preferred way for people to get around for the foreseeable future. 

Public-transportation ridership peaked in the United States in 1944 and 1945. Rapid advancements in automobile technology, combined with the passage of the Eederal Aid Highway Act in 1956, led to a decline in use of mass transit. Streetcar systems in many major U.S. cities ceased in the mid-1950 s. However, sharp increases in gasoline prices in the 1970 s renewed interest in public transportation. 

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