Yes. It happened to one of my cars which was sitting in the driveway. It was an old convertible with plenty of cabin air leaks and there’s no way that pressure built up. The pieces went outside the car, eliminating a projectile as the cause, but that’s probably what leads people to believe it’s caused by pressure. As I understand, it’s just one of those weird things that sometimes happens with glass.
No way the presssure can build up. An auto is not air tight.
Popping windows/windshields is due to improper installation of the glass and thermal expansion of the glass causing breakages.
Poster removed to protect the uninformed.
Never saw such pressure relief vents. Any specifics? Makes?
Windows never did pop out because all us geezers always cracked the windows1 
Goodness! How did you guys ever get your car doors open after a cold night when the air contracted enough to form a partial vacuum…
Oh, I know, the windows imploded during the night so you could get in the next day.
I agree with this. I had a rear quarter window explode on a freeway once while I was driving. Sounded like a gunshot. Examination of the cracked window showed no impact damage. :eek: 
It was about 60F that morning, so it was not heat related.
Ah how about any current production car? Contrary to what has been posted, usually these are located in the trunk area often just in front of the rear corners of the car. I have never seen any located in the doors, although many doors leak air live sieves. On some cars if you slam the door with all the windows up, you can hear the vents as they seal back up (SLAM [1/2 second pause]thump from back of car) While they will act as a pressure relief, they are flow through ventilation system.
It’s solar powered too, so the hotter it is, the faster the fan can turn.
That was actually an idea I thought of years ago. Unfortunately I never did anything with that idea. 
It seems like a well-designed unit like that would work well.
I don’t mean to say I think the one they’re advertising is well-designed (I’ve never seen one in person), I just mean the idea seems sound in principle!
In my experience, leaving the car windows open lowers the temperature in the car by bringing on a cooling summer thunderstorm.
Here’s a related question, if anyone knows the answer:
How much do tinted windows (especially the 5% or whatever limo tint is) help keep the inside of a car cool?
For all of the scientists out there, where’s the error in this logic?
Heat rises. Open windows (to whatever degree) allows air circulation. There is such a thing a “greenhouse” effect whereby in an enclosed environment heat will build up to a higher temperature than on the outside.
If those assumptions are correct . . . crack the window, allow for outside air to circulate into the inside environment, allow the heat to rise out. Therefore, cracking the windows has to mitigate the “greenhouse” effect.
If there is an error in the logic I would like to educate myself as to what it is. In my practical experience, cracking the windows lessens the heat build up. Maybe not entirely, but it lessens it because it physically has to.
It doesn’t have to be theoretical. I used to take naps in my SUV during lunch at the parking lot at work. You can regulate the temperature inside the vehicle on most sunny days of the year by cracking window(s) a given amount. I was pretty good at figuring out the right amount quickly. By the time full summer comes, any amount of window cracking helps but it usually takes a lot to get it where it is comfortable to sit in. I crack my windows at work all day these days but sometimes I forget. The difference is obvious although it still may be hot inside on really sunny, hot days.
I found this study.
“Heat”, or more accurately thermal energy, doesn’t rise, hot air rises because it is less dense than cold air. Sunlight strikes your car, causing every surface to heat up. The thermal energy radiates out and heats the air. If the windows are closed, the hot air can’t escape and it heats further. Some energy radiates away from the car altogether, which is why the car doesn’t heat until it melts. If the windows are open, the hot air inside escapes and transports additional energy away from the car, lowering the temperature. I haven’t made measurements, but I would say that opening the windows an inch or two makes the car maybe 5-10 degrees cooler, depending on the car and weather conditions. That’s enough to make the car less uncomfortable until the AC kicks in, but not enough to make it safe for leaving children or pets in. Even if the windows are all the way down, a car parked in the sun will still be warmer than the outside air because of all those hot surfaces. A strong enough wind might negate that effect, I’m not sure.
Back in '94, I got my Saturn tinted with this new 3M metallic tint that had some sort of fine metallic grid embedded in the tint. It was supposed to help reflect sunlight. The windows were pretty dark…the back seat and rear window were probably limo and the front windows were around 20%.
I found that the car was still hot as hell during the summer and the metallic tint didn’t do anything except make the windows so hot they’d burn you, not to mention that touching the inside glass of the window would give you a static shock during the winter.
I put tint on the back window of my 2-door pickup truck, and it definitely feels a LOT cooler in there when the sun is shining on the back of the truck.
I think while parked after a while it’s going to heat up either way. But while you’re moving and when parked for a short time, I think it makes a difference.
Every hear that there are lies damn lies and statistics? 
Take a look at this chart from your link. For the first 50 minutes the temp in the car with cracked windows is lower.
They also did not repeat the test with the windows open further than 1.5" Also they say they cracked the windows, but was this just the front 2 or all 4? Report does not say. Furthermore after the first hour test, they opened the door to return the air in the car to ambient, but did nothing to remove the heat build up on interior parts. Needless to say a fair amount of heat can radiate off a hot dash, hot seats etc. This would cause the window open test to hit the same temp sooner. :dubious:
While I agree that leaving a kid or pet in a car is a really dumb idea, I don’t think this report supports that there is no difference between a cracked window and a sealed car.
All the link shows is that you can’t save your infant’s life by cracking the windows. There is a difference between experimental results and real-world application 
.
Solar power is run by heat? So cloudy days aren’t a problem as long as it is hot?
I am wondering what would be a good set of variables to perform some decent believable tests. Heck at these temps car dealers have to be hurting, might be able to get one to indulge you a few identical cars in the back lot for such a little test.
A ruler for setting window openings, some digital thermometers, maybe several per car, identical placement of thermometers, identical facings of car relative to sun, one closed up tight, one 1" 1 window, 1" 2 windows, etc, etc 1 all the way open on all windows.
How big of a sample size would we need to get a respectable study?
The local news just did one of those “does it work?” consumer tests, where they try out the latest gimmicky product. It’s the same one thelurkinghorror linked.
The reporter put the rubber strip on top of the window, closed the door and the fan promptly snapped in half (the plastic hook hanging it on the window came off. They fixed it, put it back on, tried again and the same thing happened. She said they tried closing the door gently, closing it from the inside, putting it on the window and rolling it up before getting out (I guess you’d either put it on the back or passenger window, or get out the other side), and nothing they tried would get it to stay on.
They called customer service who told them it works better on manual windows, and it shouldn’t be used on tinted windows (which the ads don’t say).
It’ll probably be up on this page eventually.