In January 2002, the National Research Council (NRC) released their final report on Corporate Average Fuel Economy (CAFE) Standards. The report was requested by Congress and produced by a National Academy of Sciences (NAS) committee. Union of Concerned Scientists (UCS) analysis of the results from that study indicate that it is both technically feasible and cost effective to raise the average fuel economy of new passenger cars and light trucks from today’s level of 24 miles per gallon (mpg) to 37 mpg within 10 to 15 years, even if gas drops back to $2.50 a gallon.

Technical Potential

The report explored three paths to increase fuel economy, two focused on existing technologies that could be used within 10 years, and one focused on emerging technologies that could be used in 10 to 15 years. For each path, NAS estimated potential increases for each of ten major car classes (e.g., subcompacts, large SUVs). Based on Model Year 2000 market shares and NAS estimates for the 10 year potential, a fleet fuel economy of 33 mpg is possible within the decade of the report publication (2002). Using the emerging technologies added in Path 3, the fleet could reach 37 mpg in the 2012 to 2017 timeframe.  

Since the report was published, many of the emerging technologies have become available. Further, as recently noted by the panel’s chair, the report did not anticipate the progress that has happened with hybrids and cleaner diesel. The report also did not account for growing oil demand from the developed world, the full impact of 9/11, or Hurricanes Katrina and Rita.

Even with the limits on the panel’s work, the results are in close agreement with UCS analysis of fuel economy potential. While the panel either increased the weight of the vehicles or left it the same, UCS included the potential for even more improvements using high-strength, advanced materials to safely reduce vehicle weight.

Cost Effectiveness

In evaluating costs, the NAS report undertook what they called a “cost efficiency” analysis. This analysis identifies the fuel economy level where consumers save the most money, assuming a gasoline price of $1.50 per gallon. However, as analysis of the report shows, the higher the fuel economy the better when gasoline is at $2.50 per gallon.

UCS’s analysis of the NAS cost and fuel economy projections show that the technologies available for a 37 mpg fleet would yield very positive consumer benefits, saving drivers $2,500 more at the pump than the cost of the fuel economy improvements. Even in this case the NAS did not consider the use of hybrid technology, cleaner advanced diesel engines, or advanced high-strength materials, which would have made the potential fuel economy, and the savings to consumers, even higher. 

Safety Impacts

The NAS committee could not come to agreement on the question of safety and fuel economy. Some panel members dissented from the conclusion that past fuel economy improvements have had a negative impact on safety. They cite several problems with the majority analysis. The majority findings are further predicated on the assertion that past data can be used to evaluate current and future safety implications.  However, it is clear that the cars and trucks of today are not the same as those from 10-20 years ago—and those differences drastically influence the nature of accidents today. Since the release of the panel’s report, several studies have shown that increasing weight is bad for highway safety. These studies cast further doubt on the theory of fuel economy having negative safety impacts.

UCS and the Center for Auto Safety, in both Building a Better SUV and Drilling in Detroit, demonstrate that fuel economy can be improved while actually improving safety. First, both the NAS and the American Council for an Energy Efficient Economy conclude that large fuel economy gains are achievable simply through technical modifications that do not affect vehicle safety in any way. Second, if there is serious concern about the fact that over 40,000 people die on U.S. highways every year, then a significant focus should be placed on the most important factor, vehicle design—safety standards should be tightened to require better technology to avoid crashes and better protect occupants when crashes do happen. Third, even if weight were to be taken out of vehicles, high-strength materials that have superior crash safety performance can be used and vehicle size, a more important safety factor, can be maintained. Finally, reducing the weight disparity between heavy vehicles and light vehicles can actually improve safety of the overall fleet.

Regulatory Loopholes

Light Truck Loophole. The NAS committee found that the distinction between cars and light trucks “has been stretched well beyond its original purpose.” [p. ES-4] and will lead to further erosions in fuel economy as new trucks replace older vehicles that had higher fuel economy.  Recently enacted rules from the National Highway Traffic Safety Administration claim to address this, but since they only apply to light-trucks the rules will not close the loophole.

Dual-Fuel Loophole. NAS also found that oil dependence is being increased by the CAFE provision allowing dual-fuel vehicles (vehicles that can run on gasoline or an alternative fuel) to garner extra CAFE credits and calls for the elimination of the credits. Less than one percent of these dual-fuel vehicles ever use alternative fuels. Instead of closing the loophole, it was extended in the final version of HR 6, the recently enacted energy bill.