Washington — After years of wandering down the back roads of the US bureaucracy, the issue of auto air bags may finally have reached a resolution. Under a regulation issued Wednesday by the Department of Transportation (DOT) , new cars sold in the United States after 1989 must have air bags, automatic seat belts, or other ''passive'' safety devices as standard equipment.
The requirement won't take effect, however, if states comprising two-thirds of the US population make it illegal to not buckle up your old-fashioned, manual seat belt.
This approach to auto safety ''will save as many lives as possible, as soon as possible,'' Transportation Secretary Elizabeth Dole said at a press conference.
Air bags and passive safety equipment first rose to national prominence around 1970, when the federal government began considering making them mandatory in new cars. Since then, the issue has suffered through some 60 different regulatory proceedings, with congressional investigations and court cases almost too numerous to follow.
By now, there are few arguments about whether passive restraints would be effective. Experts figure they would save some 9,000 lives a year.
At issue is whether the US public will accept the intrusive effects and cost of the devices (DOT estimates that air bags, for instance, would add $320 to the price of a new car). Opponents also argue that other approaches, such as mandatory selt-belt laws, might be more effective lifesavers.
The Reagan administration, when it took office, at first decided that passive safety equipment wasn't worth the cost, and threw out a Carter-designed rule that would have required the devices by this year. The US Supreme Court in 1983 decided that move was ''arbitrary and capricious,'' and ordered the Transportation Department to think about air bags again.
Wednesday's action was the result of this reconsideration.
Under the rule issued by Secretary Dole, use of passive restraints will start slowly and crescendo over the next six years. Ten percent of all new passenger cars sold in the US after Aug. 29, 1986, will have to have the devices, with the requirement rising gradually to 100 percent of new cars after Sept. 1, 1989.
The regulation doesn't require use of a particular technology. It only requires that front-seat passengers be automatically protected from harm in crashes at speeds up to 30 miles per hour. Manufacturers would receive extra credit, however, for using air bags or such new devices as ''passive interiors, '' in which passengers would bounce around harmlessly.
If enough states make the wearing of traditional seat belts mandatory during the next five years, the rule won't take final effect, Mrs. Dole explained. The New York legislature has already passed such a law, requiring a $50 fine for those caught unbuckled. In a recent Gallup poll, however, 65 percent of those surveyed opposed fines for not wearing seat belts.
''Seat belts are the most rejected auto-safety technology,'' says Joan Claybrook, chief of the National Highway Traffic Safety Administration under President Carter and now head of the Ralph Nader organization Public Citizen.
The new rule ''is very confusing,'' she says, and may be designed to undermine adoption of air bags. Mr. Nader himself calls the action ''too little, too late.''
Auto companies were not angry over the ruling. ''We are pleased to see Secretary Dole recognize the dramatic lifesaving potential of mandatory seat-belt laws, and provide they can be an alternative,'' says General Motors spokesman James Farmer. GM, according to Mr. Farmer, will push hard for states to pass such laws.