If sales trends don't change dramatically, Toyota will sell more cars in the United States this year than each of the two brands that have dominated for a century: Chevrolet and Ford.

It would mark the first time a foreign automaker has held that mantle and illustrates the growing impact of Toyota Motor Corp., Honda Motor Co., Nissan Motor Co. and Hyundai Motor Co., all of which continue to expand their domestic lineups and manufacturing capacity.

"What you're seeing from Toyota is an expansion into new segments, both on the production and sales side, and a further entrenchment of their strong sales position in current vehicles like the Camry and Corolla," said Michael Robinet, vice president of global forecasting for CSM Worldwide, which provides market information and forecasts to more than 350 automotive suppliers.

On the passenger car side, Toyota, excluding its Lexus luxury brand, sold 520,991 cars in the United States through July, about 20,000 more than Ford and nearly 47,000 more than Chevy, General Motors Corp.'s top-selling brand.

Ford has been the top car seller in the United States for nearly a decade, although Toyota's Camry was the best-selling model last year.

One of Toyota's new converts is Jim Harper, 69, of Vandalia, Ohio. He was looking to replace a 7-year-old Chrysler with a new one when he test drove a 2003 Camry recently. He liked the performance and knew about the automaker's quality ratings and therefore opted for the Japanese make over another Chrysler product.

"When I get a new car, I like to hang on to it for six or seven years," said Harper, who owns a custom frame shop. "I don't want to spend half my time in a service department."

Despite Toyota's gains, U.S. automakers still dominate the overall domestic vehicle market, where trucks and sport utility vehicles are bigger sellers than cars. But Detroit's Big Three have seen market share declines this year.

For the first seven months of 2003, GM's U.S. market share was 27.6 percent, down from 28.5 percent a year ago, according to Autodata Corp. Ford Motor co. was at 19.6 percent, down from 20 percent. DaimlerChrysler AG fell to 13.2 percent from 13.5 percent.

Meanwhile, through July, Toyota's overall U.S. market share was 11 percent, up from 10.4 percent, and Honda was at 8.2 percent, well ahead of its 7.1 percent share a year earlier.

Analysts say market share figures for Asian automakers are likely to keep growing as they enhance their lineups with vehicles aimed directly at the Big Three — pickups and SUVs.

But GM, Ford and Chrysler, all of which have focused on their truck and SUV lineups in recent years, say they're in no way willing to concede the car market to Toyota or anyone else.

Chrysler has said 14 of 21 new products during the next few years will be car-based.

GM, the world's largest automaker, will introduce a new Chevy Malibu this fall, a high-volume car that will compete directly with the Camry and Honda's popular Accord. GM also will launch the Chevy Cobalt to replace the Cavalier next fall, the same time Pontiac will begin building a new midsize car, one notch above the Grand Am.

Ford also has ambitious plans for its cars, although Ben Poore, the Ford Division's car group marketing manager, acknowledged that Ford spent much of last year beefing up its SUVs and this year doing the same to its trucks and minivans.

"I'm not surprised to see the Toyota numbers," Poore said. "They have a much fresher product lineup than we do in cars. But guess what? We're coming back, and we're absolutely coming on with a vengeance."

Among Ford's new offerings in the next couple of years: the large Five-Hundred sedan, the GT supercar, a new Mustang and the Futura, which will be positioned between the smaller Focus and the Five-Hundred.

For all its gains, Toyota says it's pleased, but that market share gains in particular are not its priority. The automaker says its reputation for dependability and products with broad appeal are what fuel sales.

"Our focus is on what we can control," said Ernest Bastien, corporate manager for Toyota's vehicle operations group. "We look at where we're positioned in the market, how we can best take care of consumers, and we allocate our resources accordingly."

CSM Worldwide and J.D. Power and Associates both predict Chrysler — which includes the Chrysler, Dodge and Jeep nameplates — will maintain its No. 3 position in the domestic market during the next five years.

Jeff Schuster, J.D. Power's director of North American forecasting, said he expects Chrysler to maintain a sales gap of 400,000 to 500,000 vehicles over Toyota and its Lexus and Scion brands in the United States.