WASHINGTON -- Which is safer, a car sold in the Europe or the United States?

Automakers see little or no difference, but they have struggled to win over regulators, who are wary of an industry push to make safety standards interchangeable across the Atlantic through a free-trade deal.

Now the car companies are asking academics to help them press their case.

This week lobbyists for U.S. and European automakers enlisted the University of Michigan Transportation Research Institute in Ann Arbor, Michigan, and SAFER, a transportation research group at Chalmers University in Gothenburg, Sweden, to find common ground between U.S. and European Union standards.

Automakers say that if regulators were to accept equivalent standards from their counterparts across the Atlantic, the companies could trim hundreds of millions of dollars in costs.

The reason is scale. Car companies are investing heavily in global platforms to improve efficiency, but cars sold globally, such as the Ford Focus or Volkswagen Golf, must still be re-engineered multiple times to satisfy crash-test standards around the world.

“Regulators tend to believe that their standards are the best. They have ‘not-invented-here syndrome,’ ” said Gloria Bergquist, a spokeswoman for the Alliance of Automobile Manufacturers, a Washington D.C.-based lobbying group whose members include General Motors, Toyota and Volkswagen. “We want to show them that our standards may differ in some modest ways, but the ones that we’re looking at harmonizing are essentially equivalent.”

The research initiative will be announced tomorrow at a meeting here at which industry groups, regulators and trade negotiators will discuss the proposed U.S.-EU trade deal known as the Transatlantic Trade and Investment Partnership.

The auto industry, which claims to account for 10 percent of all trade between the United States and European Union, has emerged as one of the most vocal supporters of a trade pact.

The lobbying groups funding the research project are the Alliance; the American Automotive Policy Council, which represents the Detroit 3; and the Brussels-based European Automobile Manufacturers' Association.

Robert Strassburger, a vice president at the Alliance, said it might be the most ambitious and complicated research effort the trade group has commissioned in the field of auto safety.

Controlling variables

To show that cars are equally safe in Europe and the United States, Strassburger said, researchers will have to control for variables -- such as differences in traffic patterns, driving speeds and weather -- that can affect the number of car crashes.

“If the world were simple, we could just compare fatality rates in both regions per vehicle mile traveled and call it good. But the reality is: a mile driven here is different than a mile driven in Europe,” Strassburger said. “The study we’re doing is going to account for all those differences on an apples-to-apples basis.”

And the auto industry’s push has raised concerns about a “race to the bottom” scenario, in which businesses seek to reconcile two sets of standards by pushing for the less stringent rules at the expense of public safety.

Uphill battle

Adrian Lund, president of the Insurance Institute for Highway Safety, said the car companies are fighting an uphill battle with U.S. regulators, who firmly believe their standards are more rigorous than those in Europe.

“I think there’s going to be quite a bit of angst about accepting that a European regulation that consumer advocates have had no opportunity to comment on is going to be the law of the land for the United States as well,” he said.

It is not the first time automakers have tried. In the late 1990s, car companies asked the National Highway Traffic Safety Administration to deem the U.S. and European side-impact crash tests equivalent. NHTSA rejected the petition, saying Europe’s standards did not do enough to protect rear-seat passengers.

Some U.S. benefits

But in some cases aligning regulations could have benefits for the United States, which tends to adopt new technology more slowly, Lund said. Audi, for example, has struggled to win U.S. approval for new high beams, first sold in this year’s European-spec A8 sedan, that automatically dim to avoid blinding other drivers.

“If you try to do some overarching equivalence, where a vehicle approved for sale in Europe is approved in the U.S.,” Lund said, “that clearly has pluses and minuses.”

The backers of the study have asked researchers at the Michigan institute and SAFER to gather data and come up with a methodology by late April or early May.

After that the academics would conduct an analysis and finish their report by the end of 2014, around the time Obama administration and European Commission officials say they hope to be finishing a free-trade deal.