Scientists rebut key argument for ending standards

WASHINGTON — As the Trump administration considers a rollback of strict Obamaera fuel standards, which aimed to reduce greenhouse gas emissions from the transportation sector, a recent study has provided a new argument in their favor: They might actually save lives.

One common way automakers improve the fuel efficiency of their vehicles — that is, how much gasoline they consume per mile — is to reduce the weight of the automobile. And the new study, a working paper published by the National Bureau of Economic Research in April, suggests that a reduction in the overall average weight of vehicles on the road may actually result in fewer fatalities as a result of car crashes.

This means that, even for critics who are not interested in reducing greenhouse gases from cars, there’s still an argument to be made for keeping vehicle fuel standards, said Antonio Bento, an environmental economics expert at the University of Southern California and one of the study’s coauthors.

The federal Corporate Average Fuel Economy, or “CAFE” standards, were first introduced in the United States in 1975. In 2012, the Obama administration approved a more stringent set of standards, which would steadily increase the efficiency of certain vehicles through 2025. The standards also changed some of the ways efficiency requirements are applied to cars of different sizes.

Facing opposition from the automobile manufacturing industry, the administration later conducted a review of the standards but concluded at the end of 2016 that they would remain in place. However, the Trump administration decided in March to reopen this review — meaning it could decide to weaken or remove the Obama administration’s update.

Over the decades, critics have argued that fuel standards sacrifice safety. Many of these critics have suggested that lighter-weight cars — which are typically more fuel efficient — are more likely to produce fatalities in an crash.

This may indeed be the case if you’re looking at a weight change in only one car. Say you observe a crash between two SUVs, both around the same size. If you downsize one of those vehicles to a Smart car, the chance of its passengers being injured or killed may increase. On the other hand, if you downsize both vehicles, the overall risk of fatality might become smaller than it was to begin with.

To investigate, the researchers analyzed data on vehicles sold in the U.S. between 1954 and 2005 to see how their weight changed after the original CAFE standards were introduced in 1975. Next, they collected police reports on 17 million car crashes across 13 states between 1989 and 2005, noting which ones produced fatalities and the weights of the vehicles involved.

The researchers then conducted simulations to see how these crashes might have turned out if the original CAFE standards had not been introduced and the vehicles’ weights had not been adjusted. The simulations suggested that 171 to 439 fewer fatalities occurred each year with the standards in place than without them, depending on factors such as the year and the location of the crashes.