It’s one of the most frustrating things that can happen to a driver — a rock flying off a dump truck damages your windshield or vehicle.

But many trucking companies try and avoid responsibility for the damage with signs and disclaimers on their trucks.

When you’re tooling down road, there are trucks on the asphalt that say it’s not their fault if they break your windshield. We’re talking dump trucks that carry signs warning you to keep back because they aren’t responsible for damage.

“The simple truth is — they are responsible for it,” says attorney John McCabe.

What happens on the roads keeps glass companies busy because even small rocks can cause big headaches.

Glass guy Joe McConnell, of McConnell Auto Glass, says truck debris damage happens a lot around the Triangle.

“It’s very common,” says McConnell. “I mean, every day we’re doing glass.”

But what about the warning signs on the backs of dump trucks that say things like “Keep back 300 feet” or “not responsible for windshield damage”?

“Those signs have zero legal effect,” says McCabe. “They are not binding at all. It’s fraudulent, it’s deceptive and it’s false that they are not responsible.”

But, responsibility depends how the truck damages your vehicle.

”There’s a difference between a rock falling out of a dump truck vs. one kicking one up,” says McCabe.

Here’s the basic breakdown:

  • If a rock or other debris falls off a truck and strikes your vehicle, the company is responsible.
  • If the rock falls off the truck and hits the road first and then damages your vehicle, the company is not responsible.
  • The same is true for any debris kicked up by a truck you are following. If the truck kicks the rock off the road then the company is not responsible.

Mud flaps on a truck’s rear tires are supposed to prevent rocks from flying back into other vehicles — but many dump trucks have worn mud flaps.

Our CBS 17 investigation reveals worn flaps aren’t illegal. The North Carolina State Highway Patrol says checking mud flaps is not part of the agency’s safety inspection for trucks.

“We have no Carolina statute in place for a mud flap-type law,” said Sgt. Travis Ingold of the N.C. State Highway Patrol Motor Carrier Enforcement Section.

If rocks from a passing truck damage your windshield it may be hard to figure out who owns the truck, because this state allows dump trucks not to have a rear license plate and most don’t have any company name on the back of the truck.

If your car is damaged by a passing truck, the highway patrol says let them handle it.

“Follow the vehicle, and call Star HP or 911 and follow at safe distance.’’ says Ingold.

But, you can’t always do that.

We asked McCabe if it would it be helpful if the General Assembly mandated identifying markings the rear of a dump truck — either a DOT number or company name.

“Absolutely,” he said. “I don’t know why they don’t have that to start with.”

If you do get all the information you need to file a damage claim, experts say let your insurance company battle with the trucking company. Don’t try and do it yourself.