General Motors Corp. and Ford Motor Co. said yesterday that they are rushing to adopt a new safety technology called electronic stability control, and together they will make such systems standard on most of their large and mid-size sport-utility vehicles by the end of next year.

The nation's two biggest automakers were quick to offer the new technology on 1.8 million vehicles after preliminary testing by the government and the insurance industry showed enormous safety benefits, especially for popular SUVs that ride high and are more likely to roll over during a crash.

Stability control systems, which use sensors to automatically apply brakes or reduce engine power to prevent loss of driver control, could reduce single-vehicle crashes by 41 percent, according to a study released last month by the Insurance Institute for Highway Safety. Nearly a third of all U.S. traffic accidents and 60 percent of fatal accidents are single-vehicle crashes, according to government statistics.

Many of those crashes are rollovers involving SUVs or pickup trucks. The insurance institute, which is funded by the auto insurance industry, said stability control systems make all vehicles more stable, not just SUVs.

"Clearly the new research shows that electronic stability control is very effective," said Russ Rader, spokesman for the institute. "Safety should not be an option, and evidence is mounting that [stability control] produces a significant safety benefit and should be standard on all vehicles."

Rader said such systems are so effective, they belong in a class with safety belts and air bags as essential lifesaving equipment.

At the same time, neither the institute nor the federal government has determined which of the various stability control systems offered by different manufacturers are most effective. Such systems are already standard on many high-end European imports and optional on domestic products.

Yesterday GM said it will make stability control standard immediately on many of its biggest SUVs: the Chevrolet Tahoe, Suburban and Avalanche and the GMC Yukon and Yukon XL. The Hummer H2 will get the system in 2006; models of the Cadillac Escalade and GMC Yukon Denali already feature the system.

GM's mid-size SUVs will get the system beginning next year: the Chevrolet Trailblazer, GMC Envoy, Hummer H3, Saab 9-7X and Buick Rainier. In total, GM said, the system will be installed on 1.3 million of these vehicles.

Ford's system is a bit different. Called "roll stability control," it is aimed not just at preventing loss of control, but specifically at sensing roll and stopping rollovers. Ford will make the system standard on 500,000 vehicles, beginning on 2005-model Explorers, Lincoln Navigators and Aviators, Mercury Mountaineers and Volvo XC90s. The system will be an option on the 2005 Ford Expedition.