Monday would have been Jacqueline Houck's 26th birthday. Instead, it was the day that her mother, Carol Houck, joined two auto-safety groups in seeking to prohibit the car-rental practice - continuing to rent recalled vehicles before they have been repaired - that family members blame for her 2004 death.

Jacqueline, 20, and her sister, Raechel, 24, were killed in a PT Cruiser they had rented from Enterprise Rent-a-Car to visit family near Los Angeles. Jackie was an artist, planning a trip to Costa Rica. Raechel had been in Italy as a teacher and au pair and was planning to be a translator.

The sisters visited their mother and father and headed back to Santa Cruz on Oct. 10, 2004. At 3 o'clock the next morning, her mother got the phone call of every parent's nightmares. Jackie and Raechel had been killed in a fiery crash.

In June, an Alameda County jury decided that Enterprise - which had admitted full liability in May - should pay $15 million in damages to Houck, of Ojai, Calif., and her ex-husband, Chuck Houck, of Agoura Hills, Calif.

But Carol Houck, a small-town lawyer, decided to push for a broader legacy for her daughters, who she said died a pointless death because Enterprise put "profits before safety."

On Monday, Houck joined with two groups, the Center for Auto Safety and Consumers for Auto Reliability and Safety, in a petition to the Federal Trade Commission that asks the agency to bar Enterprise from renting vehicles that have been recalled but not yet repaired.

Clarence Ditlow, executive director of the Center for Auto Safety, said records from the Houcks' lawsuit show that Enterprise did not have policies or procedures in place to keep recalled vehicles out of renters' hands.

Ditlow said that even after the jury verdict, Enterprise said it would evaluate recalls case by case. Enterprise's parent company, Enterprise Holdings, the nation's largest car-rental company, also owns the National and Alamo rental businesses.

"To us, if it's a safety recall, it should be parked until it's fixed," Ditlow said. "It's just black and white."

Enterprise spokeswoman Laura Bryant said the company stood by a July 7 statement issued by executive vice president Greg Stubblefield. The statement said the company had tightened its procedures since the Houck crash but left open the possibility that some recalled vehicles could be rented.

Stubblefield said the Houck deaths "deeply sadden all of us at Enterprise," and noted that until liability claims were dismissed in its bankruptcy, Chrysler had been a codefendant in the Houcks' suit. The Houcks contended that a broken power-steering hose on the PT Cruiser - described as a fire hazard in a recall a month before the crash - had caused an under-hood fire and loss of control that led to the sisters' deaths.

"Given all we have learned, today we would not rent the vehicle the Houck sisters were driving until it was repaired," Stubblefield said. He said that any vehicles would be withheld when recalls involved "the risk of sudden loss of control, safety-restraint failures, or fire hazards."

The safety groups' complaint centers on how Enterprise deals with recalls in which the manufacturer does not explicitly recommend that vehicles be grounded.

Stubblefield said Enterprise "has grounded vehicles even when manufacturers have not issued any such notice" when recalls are announced in conjunction with the National Highway Traffic Safety Administration.

But he did not rule out rentals when manufacturers "do not suggest grounding, but instead ask owners to contact their local dealers to schedule a service appointment" - and noted that "neither Chrysler nor NHTSA had recommended grounding the PT Cruiser."

Ditlow said the safety groups and Houck petitioned the FTC because they consider the practice of renting recalled but unrepaired vehicles a deceptive trade practice, especially when Enterprise ads tout its vehicles' maintenance and reliability.

Ditlow said the lack of a bright-line rule takes away a consumer's ability to choose how to respond to a recall.

"Consumers know the hazard if their car is recalled. Some consumers will take it in immediately. Some will wait a couple days. Some will use other means of transportation," Ditlow said. "But Enterprise isn't telling consumers that the car has a recall."

Houck said she was determined to force change at Enterprise, which she said callously put her daughters at risk by renting them a car that already had been rented three times in the weeks after the recall.

"It was the last car on the lot, and they were told they were getting an upgrade," Houck said. She said a lawsuit and damages would not be sufficient to force change.

"The amount of our verdict represented about a quarter of a day of revenue for Enterprise," she said. "It was like a little tiny pebble hitting Goliath."