DETROIT -- The U.S. government's highway safety agency has decided to seek further information from General Motors about air bag failures in some Chevrolet Impala full-size cars.

The National Highway Traffic Safety Administration began an inquiry into the issue after receiving a petition from Donald Friedman of Xprts LLC, a Santa Barbara, California, company that examines crashes.

Friedman examined an April 2011 car crash in Hidalgo County, Texas, that severely injured an elderly man named Roberto Martinez. His wife Aurora, was driving their 2008 Impala when it was hit on the passenger side by an SUV and forced into a concrete highway divider. The passenger air bags didn't deploy, and Roberto suffered permanent brain injuries, according to a lawsuit filed by the couple against GM. He died about 10 months later.

Friedman alleges that because Roberto Martinez was bounced around during the incident, the weight sensor in the passenger seat misread his weight and didn't fire the air bag. The air bag is supposed to inflate for anyone other than a child or small adult. Friedman says the cars should be recalled and the computers reprogrammed.

The petition says GM used the same system in other models from 2004 through 2010. The inquiry, which is not a formal investigation, covers about 320,000 Impalas from the 2007-2009 model years.

GM may be getting greater scrutiny from NHTSA after the company admitted knowing about a deadly ignition switch problem in some of its older small cars for more than a decade, yet it didn't recall them until this year. Eventually the company recalled 2.6 million cars for that problem, and the agency fined GM the maximum $35 million for failing to disclose information in the case.

The Martinez case was settled out of court about two years ago, said the couple's attorney, Manuel Guerra. He would not disclose the sum.

Friedman said in an interview Friday that even though the lawsuit was settled, he filed the petition so the government would address the problem. "It seemed to me that it was an important thing to get in front of NHTSA and have the other vehicles that could have had the same defect taken care of," he said.

Although NHTSA's inquiry so far hasn't found any defects, the agency will seek more data from GM "in an abundance of caution," NHTSA said in documents posted Friday on its website.

GM spokesman Alan Adler says the company will co-operate. He said GM did its own review and decided not to take any action, although he would not comment on the reasons for that decision.