In 1999, after federal regulators raised concerns that side air bags could injure passengers when deployed, the automobile industry decided to fix the problem itself instead of opening up the possibility of federal regulation. Now, faced with mounting criticism about the safety of sport-utility vehicles, carmakers are taking the same approach. They told the National Highway Traffic Safety Administration that they would try to create a voluntary standard to make SUVs less dangerous in side and frontal crashes with cars.

"There are many details to be sorted out to make all of this happen, but there is a strong commitment to move forward expeditiously," the Alliance of Automobile Manufacturers and the Insurance Institute for Highway Safety said in a Feb. 13 letter to Jeffrey W. Runge, NHTSA's administrator.

Soon after he arrived in Washington, Runge, an emergency-room physician from North Carolina, created teams to examine the increasing numbers of injuries and deaths from rollovers of SUVs and the damage they cause when they hit smaller vehicles. He then shook up the industry last month at a Detroit meeting by citing SUV rollover death statistics and telling reporters he wouldn't let his daughter buy an SUV rated poorly in rollover tests "if it was the last one on earth."

Agency staffers presented the results of their SUV work to Runge at a Warrenton, Va., retreat Feb. 11 and 12.

The automobile alliance, which represents the major domestic and foreign carmakers, is holding a briefing today to try to convince the public that SUVs, long a major profit center for U.S. manufacturers, are safe. Sen. John McCain (R-Ariz.), chairman of the Senate Commerce Committee, has called a hearing on SUV safety for tomorrow.

From its examination of the government's accident and fatality data, the car group concluded that many rollover fatalities could be avoided with the use of seat belts, and that SUVs were as safe as cars in the average front, side or rear crash.

NHTSA said its interpretation of the statistics showed a higher rate of deaths in crashes involving SUVs than in cars or vans and, in general, that there are thousands more fatalities on the road annually because of the growing number of SUVs and pickup trucks.

The industry effort doesn't specifically address rollovers. It focuses on what it calls the "compatibility" between SUVs and cars. The issue is how to minimize the differences in size and strength between the two classes of vehicles to reduce the chances of injury and death when larger SUVs hit cars in the side or ride over the top of them in frontal crashes.

The agency is working separately on a test standard to rate SUVs on their potential to roll over in certain kinds of maneuvers.

Runge told reporters right after his Detroit appearance last month, "We cannot regulate ourselves out of this mess."

Though the industry considers its voluntary side air-bag standard a success, auto safety groups say they aren't confident it would work on SUV safety problems, which might involve fundamental design questions.

And one NHTSA official said the SUV safety issue is so complex that it might not lend itself to the same voluntary industry collaboration. But he stressed that the agency needs industry input to put safer products on the road faster than it might through traditional regulating, which can take years to complete.

The quickest fix would be to use side air bags, which act as protective devices for the occupants of cars and SUVs for side crashes. The other would be to lower the height of SUVs and light trucks so they would not ride over the top of cars in front-end accidents. The longer-term solutions involve making SUVs less rigid, to ameliorate their impact with cars -- without sacrificing the safety of the SUV occupants.

"Ultimately, we'll adopt best practices. It will be industry and government working together to move the ball forward. It will be much faster than the government doing it and drawing the line in the sand," said Robert S. Strassburger, vice president of vehicle safety for the alliance.

Rae Tyson, a spokesman for NHTSA, said that while waiting for the industry results, the agency staff recommendations on SUV safety will be published in the Federal Register for comment. They are likely to include encouraging states to pass stricter seat-belt laws, possibly some new rules and perhaps a change in fuel-efficiency standards, sources said. Relying on the auto industry to regulate itself troubles auto-safety advocates, who say they are excluded from the process and there is no way to monitor compliance with a voluntary standard or hold automakers to it.

"You're relying on a promise to do better," said Clarence M. Ditlow, executive director of the Center for Auto Safety. "Even if they develop a voluntary standard, it's voluntary. Nobody has to meet it."

A NHTSA official said the agency has not yet decided how it will keep tabs on whether manufacturers are meeting the new voluntary guidelines they adopted on side air bags or how that information will be made available to the public. The alliance said 60 percent of the side air bags available in 2003 were engineered according to the working-group guidelines adopted in August of 2000.

Safety groups prefer a formal rulemaking that requires public participation and access to the work done on the rule. The relationship that the industry and NHTSA will have under the voluntary approach wouldn't require including consumer groups, or any public record of the meetings.

Gerald A. Donaldson, senior research director for Advocates for Highway and Auto Safety, a nonprofit group involved in auto and truck safety issues, said he recently attended a session of the side-air-bag industry working group, which is still meeting, but was not allowed to stay for the entire presentation. "In this group, even if invited, it's not a very welcoming atmosphere," said Donaldson.

Adrian K. Lund, chief operating officer of the Insurance Institute, said the SUV working groups will have the "necessary experts" and "presumably" will use procedures "for everyone to see."

"The government or anyone can check them," he said.