MILFORD, Mich. (AP) -- General Motors Corp. will make side curtain air bags that protect people in rollover crashes standard equipment on all retail vehicles by the 2012 model year, the automaker announced Tuesday.

The announcement was made as GM unveiled a new $10 million crash test facility in suburban Detroit that will help it study rollover crashes.

GM said it planned to perform 150 rollover tests next year at the Milford Proving Grounds to help the company better understand rollover crashes, which in 2005 accounted for about 4 percent of all crashes but 33 percent of those occupants of passenger vehicles killed on the nation's highways.

GM's new facility includes a 120-foot bay of lights, which can move from 27 feet above to within one foot of the floor and articulate to 80 degrees, allowing better illumination of the crashes that are captured on high-speed video for analysis.

Engineers demonstrated a rollover test during the facility's unveiling, which was attended by Nicole Nason, administrator of the National Highway Traffic Safety Administration.

Nason said her agency is working on rules to protect people involved in rollover crashes from being ejected from vehicles.

When asked if those rules would include rollover-protection air bags, she said: "Stay tuned."

GM said it now has rollover air bags on 43 percent of its trucks.

Nason also said NHTSA should have a final rule on electronic stability control requirements by early next year. In September, NHTSA proposed that all new cars, SUVs and other vehicles have stability control by the 2012 model year.

She lauded GM for its commitment to safety and the new facility and said it would benefit the government.

"I think continued research on rollover crashes at facilities like this one is going to be helpful to everyone," she said.

Kevin Reale, an automotive analyst at AMR research, said all manufacturers are developing similar safety systems that will make vehicles much safer in the future.

"I think everyone is probably trending down the path of increased safety, inclusive of additional airbags as well as other sensing devices that keep their occupants safe and improve stability of the vehicle to keep it from rolling over," he said.

More and more safety features will become standard equipment in the future as opposed to options, he said.

During GM's crash test, a red Buick Rainier approached a single-track ramp at more than 40 miles an hour, went airborne, landed on its side and slid into a large net anchored by retractable tension cables.

GM officials hope to find ways to keep people from being ejected in rollovers and develop sensors for rollover-enabled air bags, which can help reduce injuries and prevent ejections.

Rollover-enabled air bags stay open for five seconds compared with the basic head curtain air bag, which offers protection for about three-tenths of a second.

Bob Lange, GM's executive director for safety, said electronic stability control and rollover air bags will increase the cost of GM vehicles, but: "We think the value of providing this increased level of safety is well worth the added product cost."

GM plans to install electronic stability control on all of its vehicles by the end of 2010.