A federal court on Friday upheld the government's decision that allows automakers to postpone until 1993 a requirement for passive safety belts on a car's passenger side if the driver is protected by an air bag.

The National Highway Traffic Safety Administration last year agreed to a request by the Ford Motor Co. that allows continued use of manual safety belts on the passenger side in cars that have driver-side air bags.The ruling was challenged by Public Citizen, a Washington-based public interest group, which claimed that the ruling postpones passive restraint protection for car passengers for four years and puts them in additional danger.

But the U.S. Court of Appeals on Friday upheld the NHTSA decision, throwing out Public Citizen's suit.

Joan Claybrook, head of Public Citizen, said no decision has been made on whether to appeal the ruling.

"Essentially, what the court did is put passenger occupants (of cars equipped with driver-side air bags) in a position of a likelihood of harm when the driver will walk away from the crash," Claybrook said.

Jeffrey Miller, deputy administrator of NHTSA, called the court decision "good news for consumers because air bags will now be available sooner and in more cars."

The highway safety agency in issuing the ruling last year agreed with auto industry claims that more time was needed to develop air bag systems for front-seat passengers.

Miller said the decision creates an incentive for automakers to make driver-side air bags available while working on developing systems that protect both drivers and front-seat passengers.

An air bag is a device that inflates rapidly in an automobile collision, protecting a driver's head and upper torso, before it rapidly deflates.

The Transportation Department several years ago directed automakers to phase in passive restraints - either air bags or belts that automatically wrap around a person entering a car - with all cars to be equipped with the devices by the fall of 1989.

Last year's ruling, which was upheld by the court Friday, postponed the requirement in the case of front-seat passengers in any car where the driver is protected by an air bag.