So, I was driving home from our local YMCA tonight, only to find a nice crack running across my windshield... Nothing hit it, and was only goin about 50. It was pretty warm here in Jersey today, so cold didnt affect it. This happened to my dads 07 impala as well, just randomly cracked on him. I am so pissed I have to pay to fix that now...

 

Sounds like a stress fracture. Thats a problem with the unibody cars, without a real frame, the bodies flex alot and can lead to things like that.

 

Stress cracks can happen but are extremely rare. Take a very close look at the crack in the area where it originated and I'll bet you find a very small,sometimes barely detectable chip that createsthe fatigue that leads to the crack starting.After it starts, thermal expansion & contraction plays a role in the crack getting bigger.

 

Posting that Farfig posted by accident in another thread. He meant it to be here.

If its not in your field of vision, and it looks like it might potentially lead that way. Grab a can of canned air, turn it upside down so cold air comes out(don't get that on bare skin because it can cause frost bite. Anyways. Spray in on the crack in the direction you want it to travel. I did it on my old car. It was a temporary fix till i replaced the windshield, that way the crack didn't move into my field of vision.

I dunno if they has a chance of breaking the glass or anything. I haven't heard of it happening, but you never know.