A side window that suddenly blew apart on a car for no apparent reason makes rock chips an even less likely explanation than ever, according to an auto consumer advocate.

Melanie Marchand was driving on Highway 16 west of Edmonton, when the passenger side window in her 2012 Gucci Edition Fiat 500 suddenly shattered with a loud bang, spraying her and the interior with thousands of pieces of broken glass.

“There was no one around me ,” she said. “It’s the passenger side window and I’m in the the right hand lane. How does that happen?”

Though startled, Marchand managed to get the car safely stopped on the shoulder.

But getting the window replaced is proving to be more difficult.

Chrysler Canada won’t replace the window because it doesn’t consider it defective.

In a statement Chrysler Canada said it wasn’t aware of any reports similar to that of the Marchands.

No proof of defect, Chrysler says

Glass isn’t covered under warranty unless there’s proof of a defect, said LouAnne Gosselin, Chrysler’s head of communications. 

Gosselin said such a defect or an improper installation would have made itself apparent before now.

shattered side window

Neil and Melanie Marchand insist the shattered window was defective. (CBC)

“This glass has been through two thermal cycles already (purchased in April 2012).  If the glass was defective or improperly installed, it would not have lasted this long,"  Gosselin wrote.

It wasn’t a decision Marchand’s husband Neil was expecting to hear.

“I was extremely upset,” he said. “This is ridiculous.

“They basically said, 'It’s an insurance issue, go talk to your insurance.' I think this is a warranty issue they should cover. This is not normal.”

Marchand said he found other complaints in online car forums of the same window blowing out on the same model Fiat in the United States

“There’s no doubt in my mind (this is a defect),” Marchand said. “It’s a very low sales-volume car and the fact three or four happened in the past 6 months demonstrates to me it’s a design flaw,” he said.

Rock theory 'pure fantasy,' author says

Although there have been some manufacturers’ recalls, mostly for glass sunroofs, most manufacturers and glass installers say windows explode because they have been weakened by a stone chip.

But Phil Edmonston, author of the Lemon-Aid guides, said he believes rocks are a convenient excuse for poor materials or improper installation.

“Generally these explanation are just pure fantasy,” Edmonston said.

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“A rock isn’t going to attack your side window. It defies science.”

“What’s happening is these parts are becoming generic and are being sold by outside suppliers who are looking for the cheapest price,” he said. “And because you’re using this part across a number of automobile lines, you’re going to have this happen across many car lines.”

Edmonston believes the Marchands and others will be successful if they take car makers to small claims court.

“In most of the consumer protection legislation in most of our provinces there is a thing called the balance of probability,” he said.

“Provincial courts have held ... that if the explanation sounds bizarre then it probably is,” he said

“Don’t take ‘no’ for an answer. They’re going to come  with many probabilities, but the most likely one is they have a defective part and they’re responsible."

Laminated windows cost more but won’t shatter

Zul Lila, of Jeff’s Auto Glass, said shattered side windows are becoming commonplace.

“Sometimes in a week we get five to eight of these and it’s the same story from every driver. They’re just driving down the road and window just spontaneously shatters on them,” he said.

Lila believes rocks are still the likely cause, but shattering glass poses an unnecessary safety hazard.

“It’s a very scary experience. Most people would start swerving left and right.”

Lila said tempered glass shatters so people can get out in the event doors are jammed in an accident, but said glass that suddenly explodes on the highway also poses a hazard.

Lila said a few manufacturers have begun using laminated glass similar to that used in windshields.

“This window will never explode on a driver or passenger. Just crack and stay in place,” he said

“It was almost experimental to see how it worked, how the manufacturers liked it, and it’s becoming standard now.”

But laminating two sheets of glass together will likely cost more.

“You’re probably looking at twice the cost in just raw materials in glass,” Lila said.

Neil Marchand said cost shouldn’t be a factor in deciding what glass to use in a vehicle.

“This is more of a safety issue,” he said.

“You get glass exploding in someone’s face it’s extremely dangerous. I know my wife and her ability to drive, but my mother-in-law, she’d be in the ditch for sure.”