The average age of all light vehicles on U.S. roads rose to a record high of 11.4 years in 2013, up from 11.3 years in 2012 and 10.8 years in 2010. The data comes from the latest survey conducted by IHS Inc. (NYSE: IHS) subsidiary R.L. Polk & Co. The company reviewed more than 247 million U.S. car and light truck registrations in January of this year to retrieve the data.

The rise marks the 11th consecutive year that the average age of U.S. cars has risen, beginning in 2002 when the average was 9.8 years. The average age of passenger cars is now 11.4 years and the average age of light trucks is 11.3 years, both record highs.

According to the Polk survey, the number of 6- to 11-year-old vehicles declined slightly at the same time that vehicles more than 12 years old increased by 20%.

Auto industry analysts cite two reasons for the increasing age of the U.S. auto fleet. First, the shaky U.S. economy has encouraged car owners to hold onto their vehicles for longer. Second, quality improvements in engineering and manufacturing have made vehicles last longer.

There is some good news for automakers in this report, though. The aging fleet means that demand is building — if slowly — among consumers. New auto sales have been rising steadily since 2010 and are on track to move 15.6 million cars in 2013. In 2007, before the U.S. recession, new car sales topped 16 million units.