The Washington PostDemocracy Dies in Darkness

Experts question logic of Trump administration’s claim that low gas mileage saves lives

The Trump administration claimed Thursday that in addition to lowering the price of vehicles, it can save 12,700 lives over the coming decades by weakening Obama-era emissions standards for cars and trucks. But that estimate relies on assumptions that have been questioned by experts in and out of the federal government.

The proposal would freeze tailpipe pollution standards at an average of 37 miles per gallon in 2020, instead of raising them to more than 50 mpg by 2025 as set under President Barack Obama.

Half of the deaths the Trump plan says it would prevent are based on the idea that making new cars more efficient would make them cheaper to drive, because people wouldn’t have to spend as much on gas. That would lead people to spend more time on the road and increase the potential for fatalities.

According to the Trump administration’s logic, cars that burn more gas and are more expensive to drive will be used significantly less, and so will lead to 6,340 fewer deaths.

The other half of deaths that would come from sticking with Obama-era standards, according to the Trump fuel-efficiency proposal released Thursday, would fall into two other basic categories.

The first is linked to the argument that technologies to make vehicles more efficient are expensive, which will drive up new car prices, reduce sales and keep some motorists behind the wheel of older cars that are less safe.

The second chunk is more mysterious, and has become a particular source of wonky debate and speculation among the small group of experts trying to digest the dense tables and thousands of pages of analysis that underpin the new fuel-standards proposal, which is one of the Trump administration’s most aggressive regulatory rollbacks.

Jeff Alson, a senior engineer who spent a decade working on the emissions standards at the Environmental Protection Agency, says this second category in particular, even with numerous unknowns, points to major shortcomings in the administration’s proposal.

That category is based on a “wacky”-seeming set of numbers that suggests an argument he had never encountered in four decades of environmental work with the agency, Alson said. The Trump administration seems to be saying that jettisoning the Obama-era standards will not only get more people to buy new cars — which may or may not be true, Alson said — but it is also saying it will get other people to drive their old cars even less.

“It’s making up the fact that people will drive less in their used old cars, and that’s a major blunder,” said Alson, who retired from the agency in April. He added that he doesn’t “know whether it was conscious or not.”

But the reduced driving is a major factor in the administration’s argument that it can save lives, he said.

Backup tables released last week show the administration assumes, depending on how it is counted, that in the coming decades Americans will drive between about 1.5 trillion and more than 3 trillion fewer miles than they otherwise would under the Obama standards, he said. That’s a difference of a few percentage points a year, Alson said.

“You shouldn’t blame the standards for whether people are driving more or driving less. Those are choices people make,” Alson said. “They’re not saving lives because the vehicles are safer. They’re saving lives in the model because people are driving less, which accounts for the bulk of the fatalities.”

The EPA directed inquiries to the Department of Transportation, which did not immediately answer questions about whether its model appears to have a major flaw, as Alson asserts.

The proposal, released jointly by the National Highway Traffic Safety Administration and EPA, does acknowledge that some of the decrease in driving under its plan — and thus lives saved — would be based on “consumer choice.”

Because of that, the administration said the dollar figures in its cost-benefit calculations do not include monetary values for the lives that it claims will be saved through the “rebound effect.” That is the technical term for the concept that more efficient cars will be driven more.

Analysts say the rebound effect is a real phenomenon. It is also true that more driving is associated with more deaths, which transportation researchers have tracked at times when the economy is picking up, for example. But critics said the Trump administration has far overstated the rebound effect, saying it will be twice as big as what analysts working in the Obama administration assumed.

That bigger estimated effect of better mileage on driving behavior helped boost the death totals the new proposal said would occur under Obama-era standards.

In the proposal released Thursday, those lives were tallied up and used to make the administration’s public case for its new plan.

“The fatalities are included because they are in fact physical impacts of the proposed standards, and it is important to present that transparently,” the department said in a statement.

Backers of the administration’s emissions plan say it is intended to reduce the burden that regulations place on industry and to find the right balance among the environment, economy and public safety.

“We are delivering on President Trump’s promise to the American public that his administration would address and fix the current fuel economy and greenhouse gas emissions standards,” said EPA Acting Administrator Andrew Wheeler in a statement. “More realistic standards can save lives while continuing to improve the environment.”

Transportation Secretary Elaine L. Chao said the proposal “will promote a healthy economy by bringing newer, safer, cleaner and more fuel-efficient vehicles to U.S. roads and we look forward to receiving input from the public.”

Several Republican lawmakers, free-market advocates and oil and gas interests praised the move.

Others have been highly critical, including health and environmental groups, but also experts whose own research is cited in the administration’s proposal.

Antonio Bento, a professor of public policy and economics at the University of Southern California, said Trump administration officials seemed to have “cherry-picked” the effects that would lead to the conclusion they wanted: that more efficient cars would be more expensive and lead to more traffic fatalities.

But Bento, whose work was referenced throughout the analysis, said the real-world evidence doesn’t support such an assumption.

For starters, he said, the administration’s estimates that complying with Obama-era requirements would cost more than $2,000 per vehicle do not account for flexibilities that manufacturers have and the advances in technology in recent years. But he said calculating that vehicles would become more expensive allowed the administration to make another key argument: that higher prices would lead people to delay purchases and stay in older, less-safe cars for longer.

“The minute you increase the price [in the models],” he said, “then you can start telling the story you want.”

Bento also took issue with the way the government calculated fatalities, using what he called “very simplified assumptions” that ignore the dispersion of the weight of vehicles in a crash and tying safety largely to the age of a vehicle. In addition, he said that administration officials essentially cut the climate-related benefits of higher fuel economy standards “down to nothing.”

The Obama administration had used a widely accepted figure of $40 per ton to calculate the “social cost of carbon” — which measures the economic harm from emitting one ton of carbon dioxide into the atmosphere. The Trump administration reduced the benefits of reducing carbon dioxide emissions to $5 per ton.

“When you put it all together, you have a very problematic document,” Bento said. “One can be sympathetic and provide constructive feedback when there are a few mistakes, and mistakes that are done with no intention. But when you look at this entire document, I don’t think these mistakes happened by accident. . . . I would not call these mistakes. I’d call it deliberately scaling down the benefits and inflating the costs.”

Ultimately, Bento said, he also worries that the Trump administration’s approach will prove “very shortsighted” — that it possibly might save automakers money in the short term but put them at a competitive disadvantage in the global marketplace in the long run.

As for the analysis overall: “I do not think it’s defensible. I do not think the assumptions as a whole are correct.”

Juliet Eilperin contributed to this report.