However, for a number of reasons, including the energy density of petroleum fuels, the internal combustion engine has been the power source of choice for automobiles and most other vehicles. However, with the oil shocks of the past few decades, as well as an increasing awareness of the emissions of air pollutants and greenhouse gases from cars and trucks, interest in the use of electrical power train systems has grown. PNGV focused on near-term goals and the development of hybrid electric vehicles, while FreedomCAR, which replaced PNGV in 2002, focuses on long-term research on fuel cells and hydrogen fuel. Japanese manufacturers were the first to introduce high-efficiency gasoline-electric hybrid vehicles in the U.S. market. Four advanced propulsion technologies of key interest are electric vehicles, hybrid vehicles, plug-in hybrids, and fuel cell vehicles. However, as with pure electric vehicles, maintenance of the electric components in hybrid vehicles generally must happen at licensed dealers, who will have more access to the technology. Many of these demonstrations are in conjunction with the California Fuel Cell Partnership, a consortium of auto manufacturers, fuel providers, fuel cell developers, and state and federal agencies. Further research and development would be necessary to achieve these benefits. In January 2002, the Bush Administration announced the FreedomCAR program, which focuses federal vehicle research on fuel cell vehicles. To complement this program, in January 2003, the Administration announced the Hydrogen Fuel Initiative, which focuses research on hydrogen fuel and infrastructure, as well as research on fuel cells for other applications (e.g., backup power). Component Technologies

Another way to improve the fuel economy and emissions characteristics of vehicles is to use advanced components that reduce friction, decrease vehicle weight, or improve system efficiency. This technology is already available on consumer EVs and HEVs. The three key issues for the marketability of advanced technology vehicles are cost, infrastructure, and performance. Therefore, research and development has been a key issue in the discussion of these vehicles, as have efforts to make the vehicles more affordable and the infrastructure more accessible.
Research and development of cleaner and more efficient vehicle technologies has been ongoing for the past few decades. Much of this research started in response to the oil shocks of the 1970s, which triggered concerns about rising fuel costs and growing dependence on imported fuel. The urgency of those concerns was lost as fuel prices declined in the 1980s and 1990s. At the same time, however, rising concerns about vehicle contributions to air pollution and global climate change added a new dimension to the issue. Recently, instability in world oil prices and political concerns have reawakened the energy dependence concerns of the 1970s. Meanwhile, research on new technologies continues, with a particular focus on commercialization. Despite widespread agreement in principle on the benefits of decreased dependence on petroleum and the internal combustion engine, the practical challenges posed by a transition to advanced vehicle technologies are formidable. Nonetheless, significant research and development progress has been made since the 1970s.
These new technologies have sparked more interest as some major auto manufacturers have introduced high-efficiency production vehicles to the American market, and others have plans to introduce similar vehicles in the future. Furthermore, interest has grown recently as a result of higher petroleum prices, and the announcement of new emission regulations for passenger vehicles.
In January 2002, the Bush Administration announced the FreedomCAR initiative, which focuses federal research on fuel cell vehicles. In conjunction with FreedomCAR, in January 2003, President Bush announced the Hydrogen Fuel Initiative, which focuses federal research on hydrogen fuel and fuel cells for stationary applications. The goal of these initiatives is to improve the competitiveness of hydrogen fuel cell vehicle technologies. However, fuel cell vehicles share many components with hybrid and pure electric vehicles. Thus, this research will likely promote advanced vehicle technologies in general.
This report discusses four major vehicle technologies—electric vehicles, hybrid electric vehicles, plug-in hybrids, and fuel cell vehicles—as well as advanced component technologies. Each technology is discussed in terms of cost, fueling and maintenance infrastructure, and performance.