DETROIT, MI - For car quality, J.D. Power's authoritative rankings for 2015 has Korean nameplates widening their lead at the top, European companies surpassing Japanese ones for the first time, and Japanese nameplates on par with domestic carmakers.

"This is a clear shift in the quality landscape," Renee Stephens, vice president of U.S. automotive quality at J.D. Power, said in the company's 2015 Initial Quality Study. "For so long, Japanese brands have been viewed by many as the gold standard in vehicle quality."

But while Japanese automakers are continuing to make improvements in quality, Korean brands including Kia and Hyundai have simply been accelerating their rate of improvement, she said.

"Leading companies are not only stepping up the pace of improvements on existing models, but are also working up front to launch vehicles with higher quality and more intuitive designs," Stephens said.

To determine the "initial quality" of vehicles, J.D. Power examined the number of problems per 100 vehicles experienced by owners in the first 90 days of ownership.

A lower number indicates a better score. As is seen at the right, Porsche topped the list for nameplates, marking the third consecutive year the Volkswagen Group brand has done so. Kia hit second place, besting all non-premium makes for the first time in the study's 29-year history.

Fiat continued to struggle, sitting at the bottom of the list.

David Muller is the automotive and business reporter for MLive Media Group in Detroit. Email him at dmuller@mlive.com or follow him on Twitter