Thousands of recalled rental cars go unrepaired for months or longer, two U.S. automakers told federal regulators the week of Feb. 21, according to the Detroit News.

However, rental car companies generally have better repair rates than consumers, who often fail to get recalled vehicles fixed.

To see how quickly rental cars vehicles are repaired, the National Highway Traffic Safety Administration looked at nearly 3 million recalled vehicles from General Motors Co., Ford Motor Co., and Chrysler Group LLC that were sold to rental car companies.

Rental car companies are not legally required to complete recalls before they rent the cars to customers. But safety advocates say some renters are driving vehicles that were recalled and not repaired.

Bob Barton, president of the American Car Rental Association, noted that hundreds of recalls and service bulletins affecting millions of vehicles in North America are issued annually. Rental car companies often place a "hold" on recalled vehicles so they are not rented until the recall work is completed, he said.

GM and Chrysler told NHTSA that 30 days after a recall,10 to 30 percent of vehicles sold to rental car companies had been repaired. By 90 days, it had improved to about 30 percent, and within a year, the number had improved to 50 percent or higher. Ford said the release of the information could damage its relationship with rental car companies and result in "decreased sales of motor vehicles to rental car fleets," so the automaker did not make its data public.

Because rental cars move around so much, it can take weeks or months for the company to find out a model has been recalled, which leads to a much longer time period before repairs take place.

NHTSA stated that dealers have a legal obligation not to sell a new vehicle that's been recalled before it is fixed.

The government's review covers 29 models - from sedans to minivans to sport utility vehicles - built from 2000-2010.

The Center for Auto Safety, a group founded by Ralph Nader and Carol S. Houck, has filed a petition with the Federal Trade Commission urging Enterprise Holdings Inc. to repair vehicles before they rent them.

Houck and her husband filed a suit against Enterprise Rent-A-Car after the 2004 deaths of their two daughters, Raechel and Jacqueline, ages 24 and 20. The sisters rented a PT Cruiser from Enterprise that, unknown to them, had been recalled for risk of under-hood fires. While traveling through Monterey County in California, the car caught fire, causing it to collide with a semi-trailer truck, killing the women, the petition said. Trial was held on the issue of damages only and the couple won a $15 million verdict in June.