Cracking Open Car Windows: Any Studies

[Rick]

@garygnu

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 .

Nice backpedal. :dubious:
Well from your post

I found this study.

It was a little hard to tell.

Furthermore, from the quote you posted

Conclusions. Even at relatively cool ambient temperatures, the temperature rise in vehicles is significant on clear, sunny days and puts infants at risk for hyperthermia. Vehicles heat up rapidly, with the majority of the temperature rise occurring within the first 15 to 30 minutes. Leaving the windows opened slightly does not significantly slow the heating process or decrease the maximum temperature attained. Increased public awareness and parental education of heat rise in motor vehicles may reduce the incidence of hyperthermia death and improve child passenger safety.

It gives no indication that you believed that there is a difference between the real world and experimental results.
Look I have seen this type of question before, and have gone so far as to place thermocouples in parked cars and watched the temps rise. It is very dangerous to leave a kid or a pet in a parked car. But with that said like Shagnasty I have also sat in cars at the mall while my wife is in shopping and I can state for a fact that on a moderate day, you can control the temps in the car by lowering the windows. The methodology in the linked study, sucks IMHO. They set out to prove that it gets hot in cars, and did so. They did not prove that there is/might be a way to control the temp in the car by varying the amount of window opening, and they completely ignored the fact that their second test (windows open) starts with an interior that contains way more latent heat than the first test.
Like we used to say in Chem lab. It is a lot easier to write your results and then plot your data to match.

[Dag_Otto]

@Gary T

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.

I live in an area where the springtime winds can gust at peak of 80-90 mph. It’s a rare occurance, but the high winds can cause car windows to shatter. I lost two windows (on opposite side of the car) one time.

I’m not sure what the mechanism is for the shattering. It doesn’t make sense, since cars can routinely be driven at these speeds without the windows breaking, but it does happen. Tempered glass does have internal stresses which may cause it to shatter. From the wikipedia enter on tempered glass:

The glass is most susceptible to breakage due to damage to the edge of the glass where the tensile stress is the greatest, but shattering can also occur in the event of a hard impact in the middle of the glass pane. Shattering may not happen when the damage originally occurs and can be triggered by a minor stress like heat or small drop that would not normally effect the toughened glass. If any toughened glass shows any damage it must be replaced.

[sturmhauke]

@Dag Otto

I’m not sure what the mechanism is for the shattering. It doesn’t make sense, since cars can routinely be driven at these speeds without the windows breaking, but it does happen.

Yeah, but how often do you drive sideways at 90 mph? The windshield is curved and angled to deflect wind upwards. Side windows are much flatter and more vertical. When driving, the air is moving parallel to the side windows so there is very little force exerted on them. But if you’re parked and there’s a high wind hitting the windows at a right angle, they’re not designed to withstand that and they break.

[oboelady]

While I believe cracking the windows helps, sometimes it just doesn’t matter. If you’ve never experienced the desert sun in the southwest U.S., you can’t even imagine what it’s like. I drove my Geo Storm to work, cracked both windows about 3 inches, put a thick towel over the steering wheel and shifter and went inside. When I got into the car at 5:00 that evening, I could not touch the steering wheel without burning my hands. I keep a pair of leather driving gloves in the car in the summertime so I won’t burn my hands.

And if you want to read an interesting experiment (not completely scientific, but certainly enlightening) about sitting in a car in Tucson with the windows rolled up, check out this link.

http://www.azstarnet.com/sn/printDS/134029

[handsomeharry]

@Rigamarole

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?

I got some on my 86 Lincoln Towncar about 2 years ago. Before then, it took about 20 minutes to get the interior tolerably cool. After installation, it took about 2 minutes to have the interior VERY cool. However, the man that put it in pointed out that it was outside the legal limits set by the state, but that they didn’t enforce the limits, so…
Now, I bought some for my 05 Chrysler Sebring, about 2/3 the size of the Lincoln, from the same company, but from somebody that probably didn’t think I would want to be too cool in the summer. The tinting looked noticeably lighter, and inside the vehicle, with the AC going full blast 100% it now takes about 20 minutes to get tolerably cool.
Answer: it depends on the tint.

hh

[zagloba]

Incidentally, Audi had an option on some models that included a solar panel on the roof to drive fans to ventilate the car when parked. Don’t know if this is still offered.

[ralph124c]

Why do so many cars come with black interiors? years ago, i had a car with a white interior-it was MUCH cooler in the summertime. yes, its a bit harder to keep clean-but at least i didn’t fry myself getting in in the summer!