Petya Papazova found out the tires on her car needed to be replaced when a van in front of her stopped short.
Her mechanic blamed her tires.
She said, "The truth is I never changed the tires for four years. But there was no rule or an indicator to tell me that they were due for a change."
But actually, all tires in the U.S. are required to have something called "tread wears indicators."
Once your tire wears evenly with those tread wear indicators, you know that your tire is bald and it needs to be replaced."
But Papazova is not the only one who doesn't know those marks exist. About 2/3 of people don't even know they're there.
And that means lots of us are having a hard time keeping track of our tires.
Dan Zielinski of the Rubber Manufacturers Association said, "We did a study that found about 13 percent of vehicles on the road had at least one bald tire."
But now, there's new technology to help make it clear that it's time to change.
Zielinski said, "When your tire wears out, you see this vibrant color, red or orange or, or some other color."
Nick Hodel works for the company who developed these indicators. He said, "Green, you're good. When you see yellow, you- it's caution, it's time to think about starting to replace those tires, and if you see red you should be replacing the tires."
The Rubber Manufacturers Association says it's ultimately up to tire makers to get them on the road.
They're the ones that have to build the tire, that have to meet all rigorous federal safety performance standards. And, it also has to be marketable. You put a strip of colored rubber into the tire that very much broadcasts the condition of your tire, if a consumer or consumers don't buy that product, it's not going to help anybody anywhere."
Testing on tire studs is underway in Japan, and they're already being used on the icon tires brand sold in Canada.
Hodel says, "A new tire will stop at 70 mph in about 190 ft. A worn out tire would stop at about 379 feet, which can mean the difference between life and death."
Petya admits her accident opened her eyes.
She said, "You're never safe on the road, uh, when it comes to tires if you don't know, um, the specifics."
The Icon tires with the Tire Performance Indicator cost about $5 more per tire.