"Carefully examining the locations and magnitudes of fuel-related emissions indicates that the proper policy focus is on the sectors that supply fuel rather than the choice of fuels in the auto sector. Therefore, beyond fundamental R&D, policies to commercialize AFVs are not necessarily required for climate protection at present."
This National Research Council (NRC) report assesses the potential to achieve twin goals of reducing petroleum use and cutting greenhouse gas (GHG) emissions from U.S. cars and light trucks to 80 percent below the 2005 level by 2050.
ABSTRACT. Improving the fuel efficiency of automobiles (cars and light trucks) is an important means of addressing transportation oil demand and greenhouse gas (GHG) emissions. This report examines the efficiency attainable through evolutionary changes in U.S. automobiles that have fueling characteristics as well as performance, size and other attributes similar to those of today. The analysis combines results from previous engineering studies of powertrain efficiency and load reduction with new examinations of rates of technology change and cost reduction.