Sometimes they line the shoulder; sometimes they’re in the lane of traffic; sometimes they end up in the median. And, if you’re not paying attention or you’re unlucky enough, they might end up under your vehicle.

Shredded tires litter roadsides across America and are not only unsightly, but can also create a real hazard for motorists. But what can be done about them? To put it simply, probably not much.

As long as cars and trucks ply the roads, tire industry officials and state environmentalists say shredded tires are a fact of modern life we can do little to prevent.

Because of its widespread use of retread tires, the trucking industry is often blamed as the main culprit behind shredded tires on America’s roads. But that blame is misguided, according to both the tire industry and the Missouri Department of Natural Resources (DNR).

"Tire debris on the highway is of great concern to our industry, but the facts are very different from the perception," said Harvey Brodsky of the Tire Retread and Repair Information Bureau, based in Pacific Grove, Calif. "The fact is that retread tires are not the cause of rubber on the road and there is enough documentation on this to fill an office."

Brodsky said the main cause of shredded tires is the failure of vehicle owners to maintain proper air pressure in their tires, whether the tire is a retread or not. Officials with the DNR’s Solid Waste Management Program do not dispute Brodsky’s claim.

"If a tire is driven underinflated, meaning it doesn’t have enough air pressure, it is not a question of if the tire will come apart, it’s a question of when the tire will come apart," Brodsky said. "You are asking the tire to do what it was not designed to do."

Brodsky admits that, "far too many truckers improperly maintain their tires," but said the same is true for the average motorist.

"Walk around your office and ask people when was the last time they checked the air pressure in their tires and for the most part you’re going to get a blank look," he said.

Further exacerbating the problem, Brodsky said, is that people take their tires for granted, unlike other components of their vehicle.

"If you have a dead battery, you’re not moving. If you press on the brake pedal and it goes to the floor, you’re not moving. But you can abuse the heck out of a tire and it will keep on going. Some people have four tires with four different inflations, but they turn the key and off they go."

Instead of keeping and using a tire pressure gauge, Brodsky said many motorists use a less accurate method of checking tire pressure.

"If you think you can tell how much air you have in your tire by kicking or thumping it, you might as well thump your gas tank to find out if you need any fuel," he said.

Because tire debris on roadsides is so visible compared to other forms of litter, some individuals and environmentalists have called for a ban on the use of retread tires. But banning retread tires from America’s roads would cause a bigger problem than it would solve, according to Chris Nagel, a DNR compliance enforcement section chief.

"By reusing the tire casings you get multiple uses out of them so they don’t enter the waste stream near as quickly," Nagel said. "You also reduce the energy consumption and the amount of raw materials needed to create new tires. If we banned retreads it would mean that every time a tire wore out you would have to toss the entire casing and buy a new one."

According to Brodsky, a new tractor-trailer tire costs about $450, while a retread costs about $150.

Nagel also points out that if the trucking industry were forced to buy new tires exclusively, the extra cost would likely be passed on to the American consumer.

"Also consider this," Nagel said. "The average truck tire weighs between 100 and 200 pounds. That’s 100 to 200 pounds of solid waste we’d have to deal with. Just in Missouri alone we have reclaimed more than 15 million tires from illegal dumps since 1990. If you get rid of retreads, we’re going to up that number considerably."

Like Brodsky, Nagel disagrees with those who blame the trucking industry for all the shredded tires on the roads.

"When people see a shredded tire on the highway, how do they know it’s actually a retread? Many shredded tires are due to a blowout because of a sudden loss of tire pressure," he said.

"Also keep in mind the number of tractor-trailers on the road and how many miles they travel compared to the average motorist."

Since there are at least nine retread tire plants in Missouri, both Brodsky and Nagel said banning retreads would also put local people out of work.

Nagel said state and local highway departments do the best they can to remove shredded tires from the roadside, but pointed out that the average citizen can also help.

"You can join the Adopt-A-Highway program and help pick them up," he said.