DETROIT, Nov. 22 (UPI) -- For the eighth straight year, Japan's luxury Lexus tops the list of most durable passenger cars four to five years after purchase, according to a study by J.D. Power and Associates.
Buick was the highest ranked U.S.-made brand on the survey based on responses from more than 30,000 original car owners.
In terms of long-term reliability, Lexus reported 159 problems per 100 vehicles in 4-year-old models, an improvement from the 173 problems reported per 100 vehicles in 1997 models.
Buick, Cadillac, Lincoln and Mercury were the only American cars that scored above the industry average for long-term durability in the annual Vehicle Dependability Index Study.
DaimlerChrysler's Mercedes Benz division scored below average in long-term durability for the first time, with 364 problems per 100 vehicles.
Brian Walters, director of product research at J.D. Powers, said Mercedes' quality decline was entirely because of problems that plagued the introduction of the M-Class sport-utility vehicle in 1998. The M-Class was Mercedes first high-volume SUV assembled in a U.S. plant.
Four Japanese brands -- Infinity, Acura, Honda and Toyota -- followed Lexus in long-term durability. Porsche, Jaguar and BMW also were above average.
Audi, Chevrolet, Chrysler, Dodge, Ford, GMC, Hyundai, Isuzu, Jeep, Kia, Land Rover, Mitsubishi, Oldsmobile, Plymouth, Pontiac, Saab, Saturn, Suzuki, Volkswagen and Volvo all scored below the industry average of 3.55 problems per vehicle.
The auto industry has improved initial quality -- defects that turn up during the first 90 days of ownership -- by 10 percent over 2001, while long-term dependability increased 7 percent.
"This kind of improvement in quality doesn't happen by accident," said Walters when the initial quality survey was released in May. "It takes a concerted effort by designers, engineers and assembly line workers of both manufacturers and their suppliers."
The Lexus GS 300 and GS 430 were the highest-rated cars in initial quality.
Among 2002 vehicles, the Toyota Corolla and gas-electric Prius hybrid tied for best compact car, the Chevrolet Malibu was the top entry midsize car, Buick Century best premium mid-size car, Buick La Sabre best full-size car, Ford Thunderbird best entry luxury car, Mazda Miata best sporty car and the Chevrolet Corvette top premium sports car.
The quality continued in Toyota and Lexus SUVs, which led nine product segments in initial quality.
Toyota was the class among trucks with the Tacoma named best compact pickup, Tundra top full-size pickup, RAV4 best entry SUV, Highlander best mid-size SUV and Sienna top minivan. The Ford Expedition was best full-size SUV and the Lexus LX470 best luxury sport-utility.