Detroit auto makers continue to improve vehicle dependability at a faster rate than their foreign rivals, a closely watched industry study says, but Japan-based Toyota remains the gold standard in long-term quality.

Toyota places all three of its brands in the top five in quality in the annual J.D. Power & Associates Vehicle Dependability Study, which surveyed 31,000 U.S. buyers of ’09 model cars and trucks after three years of ownership.

The quality report could prove a shot in the arm for Toyota and its U.S. dealers this year, as the auto maker moves to replenish inventories restricted in 2011 by natural disasters in Japan and Thailand and recover the resulting loss of more than two full points in U.S. market share.

The auto maker’s Lexus luxury unit scores No.1 overall in the study, while its volume Toyota nameplate and youth-oriented Scion unit also occupy the top five with Porsche and Cadillac. Scion ranks among the most-improved brands.

Owners of the Lexus LS report the fewest quality problems in the study. Altogether, eight Toyota nameplates perform better than their direct competition to give the auto maker an industry leading eight best-in-segment awards.

The performance comes despite a string of defect problems in 2009 and 2010, which prompted the recall of 11.5 million vehicles in the U.S. and resulted in a record $32.5 million in fines levied against Toyota by the National Highway Traffic Safety Admin. for not reporting the issues in a more timely fashion.

Interestingly, the owners polled for the J.D. Power study bought their vehicles at the height of the recall controversy, lending strong testimony to the strength of Toyota’s reputation for building bulletproof vehicles.

Ford earned three segment awards for top dependability with the Ford Explorer, Ford Fusion and Lincoln MKZ.

General Motors nabbed two awards. The Buick Lucerne, which discontinued production last year, and the popular Chevrolet Equinox were best-in-segment.

The Hyundai Genesis also received an award, giving further evidence to the Korean auto maker’s remarkable rise in vehicle quality.

However, many brands performing well in the study still face challenges in changing stubborn consumer perceptions, J.D. Power says, citing specifically Buick, Cadillac, Ford, Hyundai and Lincoln.

“Building vehicles with high levels of dependability is obviously a necessary element in reshaping consumer perceptions,” says David Sargent, vice president-Global Automotive at J.D. power.

“Negative quality perceptions are notoriously difficult to change, and it takes considerable time, but effectively communicating improvements in dependability may reduce concerns, and by extension, help new-vehicle sales,” Sargent says in a statement.

The industry sets a record for the fewest problems experienced by owners over the last 12 months with their 3-year-old vehicles in the study that dates back to 1990. Those vehicles previously had set a best-ever mark in another J.D. Power study measuring initial quality.

The consultant also says 25 of 32 brands show improvement in the dependability study, while six decline and one remains stable.

Detroit Three nameplates improved at a faster rate than their foreign rivals, a feat made more remarkable given 2009 marked a low-point for Ford, GM and Chrysler, with the latter two going through bankruptcy.

jamend@wardsauto.com