Jaguar and Buick topped the most dependable vehicles list, toppling the 14-year leader Lexus in a J.D. Power and Associates automotive study.The two brands were tied at the top spot as the most dependable in the US, with Jaguar climbing nine spots and Buick rising by five from their respective rankings in 2008.J.D. Power's Vehicle Dependability Study focuses on problems experienced by original owners of three-year old vehicles separated into various segments, with the scores based on the number of "problems experienced per 100 vehicles" or PP100. A lower PP100 score indicates a higher vehicle quality. This year's results were based on information gathered from 46,000 original owners of 2006-model vehicles covering a total of 202 different problems across all areas of a vehicle.Both the Jaguar and the Buick recorded a PP100 score of 122, followed by the Lexus with 126.The rest of the brands on the top ten most dependable cars are Toyota (129), Mercury (134), Infiniti (142), Acura (146), Lincoln (147), Cadillac (148) and Honda (148).The industry's PP100 average is 170."Automakers have improved long-term dependability by an average of ten percent each year since the inception of the study, which is a testament to the industry's commitment to continuously improve and sustain quality," said David Sargent, J.D. Power and Associates vice president for automotive research.Sargent added that consumers are holding off the purchase of brand new vehicles under the current economic condition, making the dependability of vehicles more important.