That's because most DOT numbers are on the inside of the tire, not the outside. Safety advocates we talked says it would be a lot more consumer friendly to force tire manufacturers to put that number on the outside. That sounds like a simple change, but so far it's not happening.
Figuring out what the DOT number means also isn't very easy.
The letters DOT on your tire means it conforms to all federal standards.
The next two numbers of letters are the plant code where it was manufactured. And the last four numbers are the date that tire was made. So the number 1208 would mean that tire was made the 12th week of 2008.
Some older tires only have three numbers at the end. For instance in our story we showed you a tire with the number 459. That means it was made in the 45th week of 1999. Further adding to the confusion, in rare cases it could also mean it was made the 45th week of 1989.
Safety advocates have pushed for change. They say it would be much easier to imprint January 2008 on a tire instead of 0208. Safety advocates also suggest that instead of inputting the manufacturing date of the tire, tire makers should put expiration dates on their tires.
They compare that to the expiration date we all look for on milk and other diary products.
Jack Crane, the father of 18-year old Bobby Crane who died in an accident when his 14-year old tires blew out, put it another way.
"The code should be on the outside of the tire where you can see it. It should be a date that's easily understood by the consumer, said Crane. "And there should be some restriction on selling tires that are past a date that makes them safe. That just seems simple to me. Why the tire companies seem to object to that, I don't understand. It's too their advantage to sell more tires. So wouldn't you think they be in favor of something like that. But apparently they're not. Why they're not, I don't understand." The National Highway Traffic Safety Administration does agree that tires do age even when not in use, like in the trunk of a car or sitting in a warehouse. In a report to congress, NHTSA cited statistics from a major, but unnamed insurance company. That company told NHTSA that 84 percent of the tire claims it received involved tires six years or older.