General Motors Corp.'s Buick brand tied Toyota Motor Corp's Lexus for top ranking in a widely watched U.S. survey of vehicle reliability released on Thursday.

The result marked the first time in 12 years that another brand had challenged Toyota's luxury nameplate for bragging-rights as most dependable in the closely watched J.D. Power and Associates survey, the firm said.

The annual survey, which was based on responses from more than 53,000 owners of 2004 model-year vehicles, tracks how many problems are encountered on average over the first three years of the life of a new car or truck.

Automakers and industry analysts track such measures of dependability closely because of their demonstrated link to customer loyalty, the residual values of used vehicles and warranty costs.

Over the past three years, Lexus and Buick owners reported an average of 145 problems for every 100 vehicles on the road, compared to an industry average of 216 problems, the J.D. Power survey said.

Rounding out the top five ranked nameplates by dependability were GM's Cadillac, Ford Motor Co.'s Mercury and Honda Motor Co'sHonda brand.

Honda Motor Co.and Toyota Motor Co, perennial favorites in vehicle quality measures, were the only two mass-market brands to beat the industry average. Ford, GM's Chevrolet, Chrysler LLC's Chrysler and Dodge brands and Nissan Motor Co. all trailed the average.

Toyota dominated the rankings of most-reliable vehicles on a segment-by-segment basis. Lexus placed first in five vehicle segments, the highest such tally in the industry.

Toyota's RAV 4, Sequoia, Tacoma and Tundra also captured best-in-segment awards for utility vehicles and trucks, while Toyota's Scion xA was named most-dependable subcompact.

For the second straight year, Land Rover was ranked as the least reliable brand in the survey. The Ford-owned nameplate cut its reported problems by 9 percent to 398, but still trailed the next-to-last Suzuki Motor Corp at 324 problems.

GM's heavy-duty Hummer brand was the most improved nameplate but still ranked below the industry average for dependability, J.D. Power said.

The market research firm said its findings showed vehicles with strong dependability rankings tend to retain up to 15 percent more of their sticker price over three years than lower-scoring vehicles.

For instance, a Scion xA might be worth up to $10,607 compared to its original sale price of $14,939 after three years, J.D. Power said. An average, by contrast, would only be worth $8,366 at the end of three years, it said.

In addition to their importance to consumers, automakers track such residual values as an important element in calculating vehicle lease payments.

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