Passenger Vehicle Standards
Fuel economy standards were instituted following the energy crisis of 1973 without consideration of how they might affect safety. These corporate average fuel economy
(CAFE) standards require motor vehicle manufacturers to increase the sales-weighted average fuel economy of passenger cars and light-duty trucks.
Fuel economy standards were instituted following the energy crisis of 1973 without consideration of how they might affect safety. These corporate average fuel economy (CAFE) standards require motor vehicle manufacturers to increase the sales-weighted average fuel economy of passenger cars and light-duty trucks.
The CAFE standards have always been controversial. Manufacturers complain that the standards run counter to market demand and impose extra costs on consumers and industry. Safety advocates complain that the standards increase risk by encouraging sales of smaller vehicles to save fuel. However, those concerned about environmental protection and the costs of imported fuel have supported the standards as necessary.
Throughout the entire period during which the standards have been applied, their actual effects on costs, sales, fuel economy, emissions, and safety have been disputed. Accordingly, in fall 2001, Congress asked The National Academies to conduct a study evaluating the effectiveness and impacts of the CAFE standards (Effectiveness and Impact of Corporate Average Fuel Economy (CAFE) Standards; NRC 2002). The Academies had conducted a similar study in 1991. In both cases, TRB provided assistance on the safety issues (the focus here), and the Board on Energy and Environmental Systems focused on energy-saving technology opportunities and costs.
In the past, manufacturers reduced the size and weight of vehicles to make them more fuel-efficient. A key debate concerns whether the ability of a vehicle to absorb energy (its “crush space”) can be retained if the vehicle is made lighter through design changes and the use of lighter-weight materials. Even within the committee, the safety issues involved were controversial. The majority of the committee members concluded that the downsizing (and downweighting) of vehicles that occurred in the late 1970s and early 1980s probably resulted in 1,300 to 2,600 crash fatalities and 13,000 to 26,000 serious injuries in 1993 (the most recent year for which a comprehensive estimate has been developed). The proportion of these casualties attributable to fuel economy standards is uncertain, however, because some consumers shifted from larger to smaller vehicles to save on fuel costs. Two of the committee members, however, dissented from these conclusions. They noted that the relationships between vehicle weight and safety are complex and difficult to measure with any degree of certainty, and the models used to estimate the safety consequences of downweighting are subject to considerable criticism.
For the future, it is not clear whether significant weight reduction can be achieved without some additional downsizing, which could be expected to result in additional deaths and injuries. The committee unanimously recommended that the National Highway Traffic Safety Administration (NHTSA) consider a regulatory system that would not provide incentives for merely reducing vehicle mass (downsizing) to meet fuel economy standards and strongly encouraged the agency to conduct additional research to resolve the debate over the safety effects of the CAFE standards. The Bush administration announced in 2005 that they would adopt the committee’s recommendation to implement revised CAFE regulations that would not encourage downsizing.