(NPN)- We all know how important it is for our cars to have four good tires. Federal mandates require vehicles built today be able to monitor tire pressure. But what about how worn down those tires are? Do you know when they should be replaced? When's the last time you even thought about it?
There's new technology to help remind you, but some argue you might not be interested - especially if it means others will know you need new tires, too.
Petya Papazova found out the tires on her car needed to be replaced when a van in front of her stopped short.
"There was probably about a distance of 50 feet and I just could not stop the car," Papazova said.
Her mechanic blamed her tires.
"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," Papazova said.
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," said Dan Zielinski, Rubber Manufacturers Association.
But Papazova's not the only one who doesn't know those marks exist.
"About two-thirds of the people don't even know that those are in there," said Nick Hodel, Tire Performance Indicators.
And that means lots of us are having a hard time keeping track of our tires.
"We did a study that found about 13 percent of vehicles on the road had at least one bald tire," Zielinski said.
But now, there's new technology to help make it clear that it's time to change. From rubber that changes color to an indicator stud that sends you a signal.
"When your tire wears out, you see this vibrant color, red or orange or, or some other color," Zielinski said.
"Green you're good. When you see yellow, you- its caution, it's time to think about starting to replace those tires, and if you see red you should be replacing the tires," Hodel said.
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," Zielinski said. "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.
"By having these indicators in their tires they're empowered to make these decisions themselves, before a catastrophic result occurs," said Pat O'Brien, Icon Tries.
As Papazova learned, bald tires can be bad news.
"A new tire will stop at 70 mph in about 190 feet a worn out tire would stop at about 379 feet, which can mean the difference between life and death," Hodel said.
Papazova admits her accident opened her eyes.
"You're never safe on the road, when it comes to tires if you don't know the specifics," she said.