DETROIT -- The average quality of new cars and trucks has improved significantly in the past year, but no one fared better than once-suspect South Korean vehicles, which for the first time top U.S. and European brands in initial quality, according to a closely watched study of 2004 models.

Led by Hyundai Motor Co., South Korean-branded vehicles have reduced initial quality problems by 57 per cent in the past six years -- dropping from 272 problems per 100 vehicles in 1998 to 117 problems per 100 vehicles this year, according to the annual report from J.D. Power and Associates, released yesterday.

Hyundai topped even perennial leader Toyota, although Toyota Motor Sales USA Inc., which includes the Lexus luxury brand, repeated as the company with the highest overall initial quality. Toyota Motor Sales had 101 problems per 100 vehicles -- 18 fewer than the industry average.

Toyota's Lexus brand was again best of all nameplates with 87 problems per 100 vehicles -- six fewer than No. 2 Cadillac, produced by General Motors Corp.

"A decade ago, as Korean manufacturers struggled with a universally poor reputation for vehicle quality, no one would have predicted they could not only keep pace but actually pass domestics and other imports in terms of initial quality," said J.D. Power executive director Joe Ivers.

South Korean brands had five fewer problems per 100 vehicles than their European rivals, and six fewer than domestic brands. But they still trail Japanese nameplates by six problems per 100.

Over all, initial-quality problems dropped 11 per cent from 2003. The industry average of 119 problems per 100 vehicles in 2004 was the lowest since the study was redesigned in 1998. The study, in its 18th year, is based on responses from more than 51,000 people who bought or leased new 2004 vehicles. Surveys were done in the first 90 days of ownership.

Among manufacturers, No. 1 Toyota was followed by American Honda Motor Co. and Hyundai Motor America (both with 102 problems per 100 vehicles) and BMW of North America (116). Those were the only auto makers to beat the industry average.

Each of Detroit's auto makers showed improvement. GM fared best, with 120 problems per 100 vehicles, an improvement from 134 problems last year.

DaimlerChrysler AG had 123 problems, 16 fewer than last year. Ford Motor Co. had 127 problems, an improvement from 136.

Porsche Cars North America Inc. ranked last with 159 problems per 100 vehicles, followed by Kia Motors America(153), a subsidiary of Kia Motors Corp. of South Korea. Kia's score was 9 per cent better than in 2003.