In a debate over whether some vehicle recalls are more important than others, several major rental car companies say they rent recalled vehicles if they believe the problem is not serious, according to a Wheels blog by Christopher Jensen at nytimes.com.

The companies said they faced so many recalls that determining what a Hertz executive called "a true safety recall" was difficult. But a National Highway Traffic Safety Administration (NHTSA) spokeswoman says no recalls are unimportant. All recalled vehicles should be fixed promptly, she said.

NHTSA, however, lacks the authority to force rental companies to act, just as it cannot force consumers to have their recalled vehicles repaired.

Rental companies have urged NHTSA to adopt a labeling system for recalls that would indicate whether a recall was so serious that the affected vehicles should immediately be parked. They also say the focus on rental companies is unfair when other fleet operators or even individual consumers are not required to carry out recall repairs.

NHTSA in March asked Dollar Thrifty, Enterprise Holdings, the Hertz Corp. and the Avis Budget Group to provide details about how they respond to recalls. All but Dollar Thrifty responded, and their letters were recently posted on the agency's Web site. Dollar Thrifty was granted an extension.

Enterprise Holdings stated that when it received a recall notice from a manufacturer, it did not rent that vehicle again "until all repairs are completed." But Enterprise added it "may rent the vehicle prior to the recall work being completed" if the recall was determined by Enterprise to not pose an immediate risk to public safety.

A Hertz committee reviews recalls. If the committee determines a recall does not "represent an imminent or potentially serious risk," the affected vehicles may still be rented out.

Avis Budget commonly contacts automakers to inquire "whether the conditions involved in the recall notice render the vehicle inoperable or unsafe to drive, or if the vehicle can be driven safely until the repairs are made."