The Trump administration has for several years been working to weaken federal vehicle fuel-efficiency standards. To justify these changes, regulatory agencies argued that more stringent standards would both cost consumers more and reduce road safety. A draft version of the new final rule, however, seems to directly contradict those lines of reasoning.

The draft of the Safer Affordable Fuel-Efficient (SAFE) Vehicles rule has not been released publicly, but Sen. Thomas Carper (D-Del.) has seen it. In a letter (PDF) to the White House, Carper says not only is the rule "replete with numerous questionable legal, procedural, and technical assertions," as well as "apparent typographical and other errors," but it also completely fails to provide the safety or economic benefits initially claimed.

Why SAFE?

The SAFE rule is part of a back-and-forth that hasn't literally been going on since the dawn of time, but it kind of feels that way. The kerfuffle all began in 2012 when the Obama administration adopted a fuel-economy standard that would gradually increase the average miles-per-gallon rating for most cars to 54.5mpg by 2025 (about 40mpg under real-world conditions). The Environmental Protection Agency finalized that standard in December 2016.

Like many regulations either finalized or enacted during the tail end of the Obama administration, though, the fuel-economy standard had a target on its back when the Trump administration began a month later. EPA Administrator Scott Pruitt in 2018 kicked off a rulemaking process to dump the 2012 rule and replace it with something weaker.

The EPA's core argument for again lowering fuel-economy expectations hinged on cost. More efficient cars would cost more to make, the EPA said, which in turn means higher costs for consumers. The agency estimated the price of a new car would go up by $2,340, hitting consumers right in the pocketbook.

From there, the argument went on, consumers would also be more at risk for injury and death in road accidents because newer cars are safer than older ones. But if prices went up, the argument goes, more drivers would instead choose to hang onto older, less safe models. The National Highway Traffic Safety Administration (NHTSA), which worked with the EPA to design the proposal, estimated that nixing the higher fuel-economy standard would save 12,700 lives through the 2029 model year.

An expert told Ars at the time that this reasoning seemed specious, noting that researchers have not yet demonstrated "a statistically rigorous association between traffic fatalities and fuel economy."

When more is less

Sen. Carper seems to agree, writing that the math simply doesn't add up. "Remarkably, the costs of the Trump administration's draft final rule exceed its benefits to Americans" relative to the current standards.

The senator writes:

While the draft final rule finds that the per vehicle purchase price would be reduced relative to the Obama rules by $977 (EPA greenhouse gas standards)/$1,083 (DOT's fuel economy standards), the draft final rule also projects that the increased gasoline consumers would have to use to operate the less fuel-efficient vehicles would ad $1,461 (EPA greenhouse gas standards)/$1,423 (DOT fuel economy standards) to these costs. Adding hundreds of dollars to the cost of each vehicle would seem to be the opposite of the more "affordable" vehicles the SAFE rule promised.

Further, Carper notes, the estimate of lives potentially saved over a nearly 50-year time period by upgrading to new cars does not take into account the lives potentially lost to illness and disease attributable to increased pollution from less efficient cars.

And of course, Carper notes, lower fuel-economy standards that result in consumers buying and using more gas, means burning more fossil fuels at a time when we should be doing the opposite.

"My office's review of the draft final rule indicates that it utterly fails to provide any demonstrable safety, environmental, or economic benefit to consumers or the country," Carper concludes. "It should be abandoned. At a minimum, I seek your commitment that you will not allow the finalization of this extreme and unlawful environmental rollback in any form that even remotely resembles" the current draft.

Meanwhile, the fight is unlikely to end with the passage of a new federal rule. A group of automakers has rallied behind a stricter standard developed by California regulators, which several other states have indicated they will also adopt. The administration sued California, which sued back; those cases are still winding their way through the court.