DETROIT, AUG. 27 -- General Motors Corp. said today that all domestically designed passenger cars will be equipped with driver's-side air bags where possible by the fall of 1995.

The world's largest automaker said last November that driver's-side air bags would be standard or optional equipment on 1.3 million 1991 models. GM said it has sold 450,000 model 1990 cars equipped with the safety devices.

Chrysler Corp. currently equips all its North American-made cars with air bags and Ford Motor Co. has air bags in about half of its fleet.

Engineering and market considerations led GM to decide to install driver's-side air bags in all domestic cars by late 1995, said Donald Postma, spokesman for GM's Technical Staffs Group.

The only GM cars lacking driver's-side air bags would be those in which the systems posed unforeseen design problems. But Postma said: ''As far as we know there won't be any exceptions.''

GM first introduced air bags as optional equipment in the 1988 model year.

Since then, the automaker has made the devices standard on some models and introduced them as options on others, which Postma said would continue until 1995.

Postma declined to say how much each air-bag system costs GM.

Air bags on the 1990 Oldsmobile 98 and Oldsmobile 88 are options costing the consumer $850, he said.

GM will begin offering passenger-side air bags in the 1992 model year, President Lloyd Reuss said in a statement.

Postma said GM is conducting research on rear-seat air bags, but there are no firm plans to offer them.

The 1.3 million 1991-model cars equipped with air bags are expected to represent betweenone-third and one-half of GM's sales for the model year.

''We feel comfortable with what we have and how they're working,'' Postma said.

Before deciding to install air bags in all cars, GM wanted to ensure suppliers could handle the production volume required, he said.

Postma added that the automaker ''wanted to make sure people were ready for this amount of safety.

"The automotive marketplace has shown that safety is beginning to sell cars,'' he said.