A new study finds that over their 40-year history, fuel economy standards in the United States have helped reduce reliance on foreign oil producers, saved $5 trillion in fuel costs and prevented 14 billion metric tons of carbon from being released into the atmosphere. The standards (known as CAFE standards), first enacted to reduce foreign oil dependence, were cost-effective, fair, durable and adaptive, the researchers find.

Using data including household spending data, oil use, and greenhouse gas emissions, the researchers found that the standards (known as the CAFE standards), which were first enacted in 1975 as a way to reduce dependence on foreign oil after the oil crisis, set well-defined societal objectives and were cost-effective, fair, durable and adaptive. The standards required automakers to produce more efficient vehicles over time, increasing the number of miles per gallon required of their vehicle fleets. The researchers cite that the standards saved $5 trillion in fuel costs and prevented 14 billion metric tons of carbon from being released into the atmosphere, the equivalent of the United States eliminating all emissions from all sectors for nearly three years.

«It has been one of the most effective policies to date,» said Judi Greenwald, a co-author of the study, former top U.S. Department of Energy official and non-resident fellow at the Princeton University’s Andlinger Center for Energy and the Environment.

The paper, coauthored by Greenwald, Rebecca Ciez and David Greene, was published on August 23 in the journal Energy Policy. Ciez was a Distinguished Postdoctoral Fellow at the Andlinger Center and Greene is a research professor in the Department of Civil and Environmental Engineering at the University of Tennessee, Knoxville. Ciez has accepted a position as assistant professor in mechanical engineering and environmental and ecological engineering at Purdue University.

«There really hasn’t been any comprehensive lookback to day one of the standards to consider what their impacts have been, how they changed over time, whether the potential threats to their effectiveness materialized or not, and their overall impact,» said Greene.

The researchers noted that the policies helped, in part, to keep the rate of yearly growth in U.S. gasoline consumption to 0.2% since 1975. The policy, in addition to fluctuations in gas prices, reduced oil imports and saved 2 trillion gallons of gasoline, enough to fuel all the light-duty vehicles in the United States for fifteen years.

Story Source: Materials provided by Princeton University, Engineering School. Original written by Molly A. Seltzer. Note: Content may be edited for style and length.