Though cars still develop more problems as they age, an American consumer organisation's survey has found that some nine-or 10-year old models can have fewer problems than some newer models.

Consumer Reports' annual car reliability survey was expanded to include vehicles up to 10 years old from the 1997 model year to 2006.

Questions relating to some of the 16 different trouble areas, ranging from the engine and transmission to body hardware and electrical systems, were also revised to give more details into the types of problems which vehicles experienced.

For example, according to CR's survey, the 1998 Lexus LS400 had slightly fewer problems than the 2006 Mercedes-Benz ML500.

The Lexus LS has been the most reliable car in the survey for years, the consumer group noted.

CR's data showed that Asian, American, and European vehicles aged differently with, on average, Toyotas and Hondas holding up best.  Ford had fewer problems than Chrysler and GM for three-year-old and older vehicles. Volkswagen showed the steepest problem increase as its vehicles aged.

The biggest increase in problem rates was between five- and six-year-old cars, but there was less of a difference in reliability between eight- and 10-year-old models as a whole, CR said.