The US auto safety regulator has denied a request to formally investigate complaints alleging potential airbag failure in certain Toyota Corollas.

The National Highway Traffic Safety Administration (NHTSA) said it had reviewed a petition by a Williamsburg, Virginia, couple and eight other complaints and concluded that further investigation of Corolla airbags would not likely turn up a defect, Reuters reported.

The petition and other documents said the vehicle’s front airbags did not deploy after the car struck a deer at 55 miles per hour in Pennsylvania in November 2009. Neither the driver nor the passenger suffered serious injuries.

Investigators found that the crash and point of impact did not sufficiently slow the car enough to activate the airbags.

“Based on the information available at the present time, NHTSA does not believe that a safety-related defect currently exists,” it said.

The agency said it would continue to monitor any new complaints.

A formal investigation would have covered up to 170,000 vehicles.

Toyota said it was pleased with the government’s decision.

Reuters noted it was the second time this year regulators cleared the Corolla of possible mechanical problems. NHTSA investigated steering complaints in 2009 and 2010 Corollas before concluding in May that it had found no defects.

Toyota has sold 154,000 units this year to the end of July, company figures showed.

NHTSA also said its consumer complaint database includes similar reports of potential airbag failure in comparable compacts made by Ford, Honda, Hyundai and General Motors .

The agency said it found nothing remarkable in the complaint rate between the 2008 Corolla and the other vehicles.

In a frontal crash tests, the model 2005-2008 Corollas received the highest government safety rating in frontal crashes.