A longtime critic of the auto industry says consumer demands for safer vehicles have created such significant improvements that "you no longer have to be afraid to buy an American car."

Auto-safety advocate Jack Gillis said that while car buyers should continue to exercise caution, "prospects for a consumer finding a pretty good car in the 1991 batch are better than ever."Gillis commented in releasing the 11th edition of "The Car Book," his annual guide to the merits and faults of the new automobile models.

For the first time in decades U.S. automakers, responding to consumer demands for safer cars and the inroads made by the Japanese auto industry, are making safety a focus of advertising rather than style and power, Gillis said.

"I think it is probably the most exciting thing that has happened this year," he said. "We are seeing, for the first time, car companies competing head to head in the area of safety."

Gillis said that competition is reflected in the manufacturing process, with more emphasis on building stronger, safer auto frames and the wider availability of air bags.

American carmakers have yet to match the attention to detail shown by their Japanese competitors, he said.

"But you no longer have to be afraid to buy an American car; that's the bottom line," Gillis added.

"What I see as the catalyst is that now that more American consumers have access to information, they are starting to vote their dollars," he said. "And American carmakers are now starting to listen to the buyer who is now demanding safer and more reliable cars."

Gillis said there also have been significant improvement in car manufacturers' warranties over the past two years.

But he said the main change has been that "you now see automobile companies shifting away from an emphasis on styling and performance to safety, quality and repairability issues."

Gillis' book, first issued in 1981 for the government but soon thereafter published as a private venture, is based on government data.

It rates cars in the areas of crash safety, repair costs, fuel economy, warranties, insurance costs, resale value and complaint history.

A central feature is the complaint index. It lists complaints registered by U.S. car owners with the National Highway Traffic Safety Administration, compiled for Gillis' recent companion volume, "The Used Car Book" and used in the latest edition of "The Car Book."

The index is the number of complaints per million cars sold - the fewer, the better.

Here are the cars with the fewest complaints per million and those with the most.

The best: Geo Prizm, 1989-91, 0; Geo Tracker, 1989-91, 0, Honda CRX 1988-91, 0; Toyota Starlet 1981-84, 0; Isuzu pickup, 1988-90, 11; Subaru Legacy, 1989-91, 31; Mitsubishi Mirage, 1989-91, 34; Chrysler new Yorker, 1988-91, 39; Nissan hardbody pickup, 1987-91, 57; Mitsubishi Mighty Max 101; Dodge Spirit, 1989-91, 103; Dodge Raider, 1987-89, 109; GMC Jimmy, 1981-91, 117; Nissan 240SX, 1989-91, 121; Mazda B Series pickup, 1986-91, 123; Geo Metro, 1989-91, 133.

The worst: Chrysler Imperial, 1981-83, 24,414; Renault 18i, 1981-85, 13,909; Eagle-Renault Med, 1988-89, 12,082; Renault Fuego, 1982-85, 8,127; Audi 5000, 1984-88, 6,927; Sterling 800 Series, 1987-91, 4,969; Peugeot 504-505, 1981-91, 4,886; Pontiac Fiero, 1984-88, 4,314; Volkswagen Dasher, 1981-82, 4,167; Dodge Mirada, 1981-83, 3,680; Oldsmobile Omega, 1981-84, 3,551; AMC Alliance-Encore, 1983-87, 3,548; Pontiac Phoenix, 1981-84, 3,426; Yugo, 1986-91, 3,368; Audi 5000, 1981-83, 3,237; Cadillac Cimarron, 1984-86, 3,227; Chevrolet Blazer, 1981-91, 3,206; Chrysler Laser, 1984-86, 3,188; Buick Skylark, 1981-85, 3,118; AMC Eagle, 3,077.