The federal government is close to proposing new auto-safety standards that would require all vehicles to have electronic stability control, technology shown to be highly effective in preventing rollovers.

Stability-control systems use sensors on the wheels that detect when a car is heading off its intended path and can automatically brake each wheel individually to get it back on course. Until recently, stability control was offered as an option or as standard equipment largely in vehicles made by luxury makers including DaimlerChrysler AG's Mercedes-Benz and BMW AG. But as studies have shown its effectiveness in preventing fatalities, particularly in rollover-prone sport-utility vehicles, auto makers have increasingly added the technology to their SUV fleets.

Some 20 percent of new vehicles sold in 2005 had the technology, up from 10 percent in 2004, and just 6 percent in 2003, according to Continental AG, one of the major suppliers of stability-control systems. Robert Bosch GmbH, TRW Automotive Holdings Corp. and Delphi Corp. are others. Still many cars, pickup trucks and minivans don't even offer the technology systems.

Now, however, the National Highway Traffic Safety Administration's proposal is expected to require stability-control systems and set a new performance standard for how a vehicle handles in sharp turns at highway speeds. Vehicles would repeatedly run through a single test that would emulate avoiding an obstacle on the highway. A driver going 50 miles an hour would jerk the vehicle in one direction and then back again, with each run-through increasing the severity of the turn of the steering wheel, until the vehicle either spins out or passes the test.

In a departure from typical practice, the proposed regulation would specifically require auto makers to adopt the stability-control technology. Normally, NHTSA establishes a test that manufacturers must meet, often with a particular technology as the way of meeting the test. But in a posting on the Transportation Department's Web site, the agency indicated this rule would go further and "require electronic stability-control systems on all newly manufactured passenger cars and light trucks."

The proposed requirement is a major step in a promised shift in emphasis at the agency toward preventing crashes. Throughout most of its 40 years, the agency has primarily worked on regulations that protect people after the vehicle crashes, such as seat belts, airbags, and its crash-testing program. Now the agency is working to play catch-up with auto makers' new technology, which in recent years has focused more on accident prevention.

The auto industry, which often opposes government mandates, is likely to support this one, says Eron Shosteck, spokesman for the Alliance of Automobile Manufacturers. "It's an innovative safety technology that has been proven in the field," he says, adding that the group's final position would depend on regulation details.

Rollovers kill more than 10,000 people a year on American roadways. Stability-control technology could save an estimated 7,000 lives a year, according to a study, and its effectiveness has been compared with that of seat belts. Not all vehicles have the stability technology available, but it comes as standard equipment or as an option on vehicles including General Motors Corp.'s Chevrolet Tahoe, Toyota Motor Corp.'s RAV4 and Volkswagen AG's Jetta. Car buyers can ask at the dealership which vehicles have it.

The agency's work on the new standard test is fairly complete, and officials hope to publish the proposal as early as this summer. First, it must be approved by the Department of Transportation and the White House Office of Management and Budget. Typically auto makers are given several years to adapt their vehicles to the new requirements, and it is unclear which model-year vehicles would first be affected by the regulation. "We've proposed something that will get it in place as quickly as we can," says Stephen Kratzke, associate administrator for rule-making at NHTSA.

In August Congress required the agency to devise standards for stability control as part of an effort to prevent rollovers. Lawmakers gave the agency until Oct. 1 to propose the regulation.

Stability control, introduced by Mercedes-Benz in 1995, has been most effective in preventing single-vehicle crashes which accounted for 21,739 deaths in 2004, the latest year for which statistics are available. Those deaths accounted for 57 percent of traffic fatalities involving vehicle occupants.

The push for the stability-control test came as the agency's own research showed the remarkable effectiveness of the technology. In a September 2004 study, NHTSA found that stability control reduced single-vehicle crashes in SUVs by 67 percent and reduced SUV fatalities by 63 percent. Passenger cars also saw a huge benefit: with single-vehicle crashes down 35 percent and fatalities down 30 percent. The results surprised agency staff, which elevated the effectiveness of stability-control technology to levels shared only with seat belts.

The following month the Insurance Institute for Highway Safety, an Arlington, Va.,-based research arm of auto insurers, published its own study with similar results. The Institute estimated some 7,000 lives could be saved annually if the technology were on all vehicles. Both studies compared crashes in vehicles that had stability control as standard equipment with crashes in the same vehicle without it. The studies also followed years of similar research results from auto makers and stability-control providers.

Following those research results, domestic auto makers announced they would make stability control standard on larger SUVs. Within months, GM took it a step further, saying it would make it standard equipment by 2010. But in the past year, no other auto maker has matched GM's pledge.