The president and the Congress have placed among the highest national objectives that of reducing fossil fuel imports (and in particular, petroleum). DOE’s EERE, parent of the FCVT and 21CTP, has as its top priority: “Dramatically reduce or even end dependence on foreign oil” by spurring creation of a domestic biofuel industry; increasing the viability and deployment of renewable energy technologies; increasing the energy efficiency of buildings and appliances; leading by example through government’s own actions; continuously improving the way EERE does business; reducing the burden of energy prices; increasing the energy efficiency of industry; and increasing the reliability and efficiency of electricity generation and use.3
While the fuel consumed per mile by light-duty vehicles improved substantially between 1966 and 2003, that of the average heavy-duty vehicle remained nearly constant (Figure 1-4). The flat fuel economy of heavy duty trucks was accompanied by a doubling of vehicle miles traveled per year (Figure 1-2). Fuel economy (miles per gallon) for passenger cars and light trucks such as sport utility vehicles and pickups rose from the late 1970s through the early 1990s. Fuel economy for passenger cars continued to rise through 2003 whereas the fuel economy of light trucks decreased from 2000 to 2003.
In fact, the U.S. transportation system relies nearly exclusively on petroleum, as shown in Figure 1-5 (DOE, EIA, 2006). That dependence grows more each year, despite attempts to substitute other fuels and energy sources.
The production of oil domestically, for its part, has declined continuously since 1985, so more and more of the nation’s fuels are imported (Figure 1-6). That fact alone makes it increasingly vital to the national interest to reverse this trend. Trucks account for increasing highway transportation energy use.
Emission standards have become increasingly stringent since the passage of the Clean Air Act in 1963. Their evolution following the passage of the Clean Air Act is discussed in more detail in Appendix D, “Vehicle Emission Regulations.” These increasingly stringent standards have dictated that new technologies be developed to comply with them. As an additional challenge, increasingly stringent emission standards for heavy-duty vehicles tend to adversely affect fuel economy at a time when there are challenges to improve fuel economy. Recognizing these dual challenges, the 21CTP adopted the simultaneous goals of improving the thermal