COLORADO SPRINGS, Colo. -

The age of your tires could be putting you at risk, according to experts.

According to the Department of Transportation, it's safest to drive on tires that are no more than six years old.

"It could blow out, you can risk an accident, obviously loss of control," Vince White, of Tire World in Colorado Springs said.

The DOT number on the side of the tire indicates their age. Consumers should look at the last four numbers following the letters DOT. The first two of those four numbers indicate the week, and the latter two indicate the year the tire was made. That number should indicate an age of no more than six years, regardless of the date purchased or how often the consumer drives on them.

"The tire's made of rubber. It's the main compound. It's going to dry, it's going to get brittle, it's going to get hard,," White said. "Just think of it as a piece of fruit. You leave it on the counter top, just because you don't eat it, it (still) goes bad. Tires are the same way."

In an ABC News investigation, Chief Investigative Correspondent Brian Ross discovered dozens of tire shops are selling tires that are older than six years.

"We also found tires that were eight, 10, 12 years old for sale at tire stores, with no sense on the part of the clerks or the mechanics that there was any possible problem with the tires." he said.

But at Tire World, White said there are no tires older than six, maybe even three years. He said that's likely the case at most big chain tire stores. Regardless of where you're buying tires from,you should check their age.

"All tire purchases should have DOT numbers written on your receipt," he said. "So you'll as soon as you buy the tires."

He said it's a federal offense if a shop refuses to give out that information.