CHARLOTTE, N.C. -- It was a routine ride to work until Wade Owens heard it.

"It sound like something exploded," says Wade.

Wade then felt small pieces of glass raining into his car and into his eyes.

The sunroof on his 2013 Kia Sportage had shattered, a scary experience, but not an isolated one.

It was no less frightening for Ayesha Farr when she heard the sound while driving in her 2013 Kia Optima.

Ayesha recalls, "It was closed. Luckily, that day it was closed. I mean, literally sounded like a gunshot. I was scared because I thought someone was shooting on the highway."

The ensuing investigation found hundreds of complaints to the National Highway Traffic Safety Administration about the problem. The complaints lead Audi and Hyundai to issue voluntary recalls on some models.

But as drivers call other car manufacturers, like Kia, to report what NHTSA has named "spontaneous sunroof breakage," the company blamed "external impacts from rocks or other foreign objects."

Don Phillips, an engineer, says, "They're not taking responsibility because they've had to make the cars lighter."

Donald Phillips consults in accident investigations and specializes in auto glass. He says there are several factors resulting in so many fractured and faulty sunroofs in recent model years.

"The main issue is that the glass in the structure around the sunroof is being made thinner in vehicles" says Phillips.

Phillips says car makers are under pressure from the federal government to make vehicles with better fuel mileage, and they're doing that by using lighter metals for the frame and auto bodies.

Kia's own investigation found no evidence of a defect, but federal regulators opened their own, noting that the rate of reported incidents is concerning. That investigation that started in May 2014, and it's still open.

Experts say, when it's really hot out, you should leave the shade to your sunroof open when you're not in the car, so heat doesn't build up between the glass and the shade that will put more pressure on the glass.

They also suggest that getting your sunroof tinted on the inside would prevent glass from showering down on you if the sunroof did break.

You can search for your car's make and model in NHTSA's database online to find out how many times others have complained about this issue happening in the car you drive.