According to a study published by global automotive market intelligence firm Polk, cars and trucks in the United States are aging – and at a pretty fast rate.

The average age of cars and light trucks currently in operation the U.S. has increased to 10.8 years. Cars have recorded a relatively small surge in age, from an average of 11 years in 2010 to 11.1 years in 2011, while the median age of light trucks, pickups and SUVs rose from 10.1 to 10.4 years.

The report says that the slowdown of the economy in 2008 and 2009, and the uncertainty it has since created among consumers, has resulted in low volume sales these two years.

Despite the fact that more trucks were sold during that period than passenger cars, their average age increased faster – a trend which Polk analysts estimate will change due to the increasingly high sales of smaller SUVs.

On the other hand, last year marked the end of the declining vehicle numbers that begun in 2008. The study shows that, compared to July 2010, the number of vehicles that were operational in July 2011 had increased by 500,000 units, to 240.5 million.

As always, there are two sides on each coin. Polk global aftermarket practice leader Mark Seng explains: “The increasing age of the vehicle fleet, together with the increasing length of ownership, offers significant business growth opportunity for the automotive aftermarket. Dealer service departments and independent repair facilities, as well as aftermarket parts suppliers, will see increased business opportunity in need of vehicle service.”