The National Highway Traffic Safety Administration announced this week that it will begin subsidizing the purchase of new cars for the federal government to ensure that they have air bags.

NHTSA has withdrawn a rule requiring that all new cars be equipped with so-called passive restraints, and has fought the issue to the Supreme Court. But NHTSA Administrator Raymond A. Peck Jr. said yesterday that the federal government's commitment to buy cars with air bags guarantees "that there will be manufacturing capability and marketing resources to make them available for everyone else who wants them."

General Services Administration chief Gerald P. Carmen added that the project is "an experimental effort to pursue a commitment to vehicle safety by means of incentive and example rather than government regulation." Under an agreement between the two agencies, GSA will include air bags in its bid specifications for new cars, and NHTSA will pick up the additional cost.

If the funding can be arranged in time, GSA plans to order the airbags in 5,000 new 1984-model sedans. The bags are expected to cost between $300 and $500 per car, but the cost could be lower on a contract as large as the government's.