According to the survey, commissioned by the National Highway Traffic Safety Administration (NHTSA), the big three in the rental car business -- Hertz, Enterprise which owns National and Alamo, and Avis/Budget -- have been letting tens of thousands of drivers go on the road without repairing defects.
Last November, NHTSA had asked the domestic car manufacturers to provide recall repair information from the car rental companies because of "incidents involving allegations of personal injury and death" allegedly caused by "safety defects" on rental vehicles.
"The bottom line shows that none of the rental car companies are doing a good job," Clarence Ditlow, executive director of the Center for Auto Safety, told ABC News.
The best overall performance came from Enterprise, but it was hardly outstanding.
In a study of 10 General Motors and Chrysler recalls, after 90 days, the company had fixed an average of only 30 percent of the cars before renting or selling them -- meaning 70 percent were not fixed when drivers took them out on the road.
For Avis/Budget, 26 percent of the cars were fixed and 74 percent were not. At Hertz, only 21 percent of the cars rented 90 days after a recall had been fixed, meaning 79 percent had not.
The study came after ABC News reported on "Good Morning America" last July on the deaths of the Houck sisters of California, 24-year old Raechel and 20-year old Jacquie, who were killed in an accident involving their Enterprise rental car. The car they were driving was a Chrysler PT Cruiser, one that a month earlier had been recalled because a possible leak in the power steering fluid could "result in an under hood fire."
The Houck's car was never fixed. Raechel and Jacquie died instantly after the PT Cruiser caught fire and hit an oncoming semi-tractor trailer on Highway 101 in Northern California. The sisters had rented the car in Santa Cruz, Calif., to visit their parents in Ventura County.
"We found out that they had rented this same car three times in that month period before they rented it to Raechel and Jacquie," Houck's family lawyer, Larry Grassini, said.
The Houcks sued Enterprise, and after a lengthy legal fight, the company admitted negligence and was required to pay $15 million in damages to the family. Now, the girls' mother Cally Houck is pushing the California legislature to pass a law requiring rental car companies to ground all recalled vehicles until they are fixed. Citing the Houck case, the Center for Auto Safety has also petitioned the Federal Trade Commission to require Enterprise to fix vehicles under recall before renting them out.
"I do not want another family to have to go through this type of ordeal," Cally Houck said.
Rental Companies Dispute Survey Findings
The rental companies dispute the survey findings and said they pick and choose which recalls are most important, and have a high rate of fix for the most serious problems. Both Avis and Enterprise noted that after a 2010 recall of Pontiac vehicles over sticking accelerator pedals, they grounded and repaired the vehicles in question before renting them out.
However, the NHTSA survey found that in the recall of a series of Chrysler vehicles with a brake problem "that could cause a crash without warning," Enterprise/National fixed 16 percent after 90 days, according to the survey, and Avis/Budget fixed 14 percent. Hertz fixed only 2.2 percent, meaning 97.8 per cent were rented or sold without being fixed.
"They cannot pick and choose," Ditlow said. "They're gambling with your life."
Hertz said it has dramatically changed its policy and told ABC News that as of last summer, it now grounds all cars recalled for any reason, and will not rent them until they are fixed -- a change of policy that grew out of the public attention drawn to the tragic case of the two sisters.
It is a position safety advocates said they hope the other rental car companies will follow. In the meantime, Ditlow said the best recourse for consumers is to simply ask rental car agents if their vehicle is subject to an outstanding safety recall.
"If they don't tell you, they're deceiving you and if they won't tell you, just go to another company, go to another counter," said Ditlow. "They're all right there in the airport, this is a free market, pick somebody who's more responsible."