TLDR: It will crack all the way sooner or later. Very dangerous.

Can a Cracked Windshield Shatter?
Phillip Thompson
January 16, 2017
By Phillip Thompson
The short answer is yes, a cracked windshield can shatter. But there are several factors involved, and realize that using the word “shatter” may not be entirely accurate. Windshield glass is laminated, meaning it consists of two layers of glass with a thin plastic film between the layers. You may have heard it called “safety” glass, as its construction prevents the glass from breaking into more dangerous shards. It usually breaks into smaller pieces.

A cracked window screen has the potential to grow as the glass expands and contracts due to temperature fluctuations, pressure applied to the glass, an object striking the glass, or dirt introduced to the crack. Any of these factors could worsen the crack – which has already weakened the glass – and cause it to “shatter.”

broken-windshield

But even if the glass does shatter, the likelihood of it collapsing into your vehicle or onto your hood, is unlikely. Windshields are held in place with strong urethane adhesives, which prevent leaks, noise and movement of the glass. Also, because the glass is laminated, the entire windshield generally won’t separate from the frame.

This doesn’t mean it’s safe to drive with a cracked windshield. Even a small crack on glass means your windshield’s structural integrity has been compromised, which means it is now a safety hazard to you and your passengers. Even if the crack or chip is small, it’s important to have it checked out. You’ll need a qualified auto glass technician to help you determine if the glass can be repaired or if it should be replaced.