My good friend [drememynd] just lost her young daughter in an automobile accident.
She lost control of the car and went off the road, upside down, into a river. She was not able to open doors or windows. Apparently she made efforts to kick the windshield out but was not successful, and she drowned.
I was thinking about how I would have responded in the same situation, and came to the conclusion that I might have met the same end.
Although I have extensive experience at task loading underwater on SCUBA, and while breath-hold freediving, I was unaware of the difficulty of getting a windshield out.
Apparently the best exit is a side window, which, if struck properly, will shatter.
But an appropriate tool is required. I've searched, and there's several marketed, but none are ideal. Finding such a tool after a crash may be challenging, since even properly secured equipment may come loose and be lost somewhere else in the car.
I would like to see a hinged device built into each door, near the corner of the window. This device would have a hardened, spring-loaded tip.
It would readily unfold and with a push of the hand or a kick impact the window and start the shattering process that we've all seen in cars that have been broken into.
You then have to wait until the car fills with water, take a breath from the remaining air bubble and exit after the inflow of water has largely stopped.
I do not wish to appear insensitive by posting this, but I consider myself relatively skilled at emergency exits, and I probably would have not passed this test. I hope that by educating people about this I can redeem some small positive thing from this tragedy.-- normzone, Nov 14 2007 (?) One of the combination tools. http://www.crystalb...ergency-hammer.htmlFlashlight, LED light,, hammer, and seat belt cutter. [Canuck, Nov 15 2007] (?) Velcro it to the door http://www.redboxto....cfm?productID=1482 [half, Nov 15 2007] Mythbuster's sinking car https://www.youtube...watch?v=2YaMEW30bv4Adam waits for the car to hit bottom before attempting escape [5th Earth, Nov 17 2007] Top Gear sinking car test http://www.youtube....tsE&feature=relatedConclusion: You can't exit until it hits bottom [5th Earth, Nov 17 2007] "Bubble Buster" http://www.safeair1.com/index.htmScroll to the bottom [Klaatu, Nov 20 2007] Manual override for power windows https://image-ppubs...downloadPdf/6021691 [ldischler, Nov 21 2007] -- po, Nov 14 2007 +-- baconbrain, Nov 15 2007 Yes, there are many tools out there (see link), but your suggestion of something spring-loaded makes a lot of sense, particularly in a situation where someone on the outside is trying to break the window under water. Perhaps a tool that can be loaded into a snap-in bracket in the glove compartment door? Or the driver's side armrest?-- Canuck, Nov 15 2007 I looked at a couple online, and talked with a comrade who is knowledgable about such things.
It comes down to bigger is better. The keychain models don't pack as much punch (read: reliability) as the models sufficiently large to make people unlikely to carry them.
And I watched a Florida Highway Patrol video that showed a large man break a side window in a completely filled car with a small hammer, apparently effortlessly, but not everybody is going to have the presence of mind or strength to pull this off.
[baconbrain], I thought about this from a few angles, and reached the conclusion that for it to be ideal:
The tool has to always be as close to the window as possible.
It has to be integral so as to prevent losing it in the chaos of a rollover (been there, done that, objects flying everywhere).
It has to be available for whatever window is useable.
That's why I want it to be standard equipment on all doors.-- normzone, Nov 15 2007 Some years ago I read a longish newspaper article on this subject. Its advice was to wait. Apparently, if you sit still, shut up and don't hyperventilate, then you can survive long enough for most of the car to fill with water. This is important, because it equalizes the pressure on the doors and windows.
Then, you take one deep breath from the remaining bubble of air at the top of the car and open a door or window (which you can now do, since you no longer have a huge weight of water pushing against you)... then, you swim to the surface.
I have not tried this.
In any case, this approach would also require a half-baked tool, in the form of an upper lip stiffener.-- pertinax, Nov 15 2007 Um, I didn't say anything earlier, just meant to express much sympathy. Is it so obvious that I'll be over-analyzing this?
I'm thinking of having something always in place, and VERY easy to operate. Like somehow making a suction-cup thing that gets glued to the window, flat enough to allow the window going up and down, having a puncher in the middle to react when hit with your elbow. Dunno how yet, though.
Or something to clip onto the seatbelt. That'd be a lot easier, although the folks might remove the seatbelt right away.
How about a law that all side windows must break from the inside under yea much blunt impact? [Later: No, I was thinking of dual-layer glass.]-- baconbrain, Nov 15 2007 I believe this issue is the result of the plethora of percieved safety and security devices incorporated in modern vehicles. Bonded in laminated screens certainly resist any attempts to kick them out. Similarly, security side glass is specifically intended not to shatter, to prevent break-ins. I wouldn't trust that any door or window mechanism would function after a crash, especially when the windows are electric and the doors have central locking.
The answer is either to do without security glass and complex locks etc, or to add more safety systems to overcome the problems caused by the existing systems.
Vehicle safety has much more to do with the perception of the consumer than anything else, so removing existing 'safety' features will not be acceptable. We will continue to add features until the vehicle will no longer move. Until then, it will keep me in a job.-- Twizz, Nov 15 2007 +-- xandram, Nov 15 2007 This was on Mythbusters recently. Ever since I've kept a screwdriver in the glovebox for just such an emergency. Aparently they make very good window breakers.-- simonj, Nov 15 2007 Howzabout making the window-breaker part of the seatbelt buckle? The buckle is heavy, metallic and either in your hand as part of getting out, or hanging right next to the exit.-- baconbrain, Nov 15 2007 If you are so worried about this issue, why not carry a small canister of pressurized air? Or emergency inflatable pontoons stored over the roof?
Yes, it is very sad that this thing happened to someone. But it remains an extremely unlikely cause of death.
Get some exercise every day, wear sunscreen, eat right, wear a seatbelt, and protect yourself from the things that WILL kill you. It will save your life a hundred thousand times over before you ever flip your car into a river.-- GutPunchLullabies, Nov 15 2007 We could just reintroduce the manual window winder handle. Then you could very calmly roll the window down, allow the car to fill then make your getaway. The neatest part of this being that all the engineering and know how to make these manual escape handles already exists.-- jhomrighaus, Nov 15 2007 Initially I wanted explosive bolts integrated into the frame/doors/windows, but I figured that might be a bit much to ask.
I didn't know they were toughening up side window glass to prevent breakins. That's going to eliminate escapes in that manner.
They also advocate popping your trunk, letting down your back seat, and exiting that way. Of course, in all the training scenarios everything is ideal - the vehicle is upright, the body is not sprung so all the doors, trunk and hood work flawlessly.
Real life is a lot more challenging. I think maybe I should stick with explosive bolt construction.-- normzone, Nov 15 2007 what happens to the passenger when you set off explosive bolts underwater?-- jhomrighaus, Nov 15 2007 The inevitable lawsuits for deafened passengers will result in hearing protection laws.
[GutPunchLullabies], regarding your comment about carrying pressurized air: During California's sporadic and violent rainy seasons, we Californians who live on the freeway have a tendency to go off the road and into flooded areas that used to be parks or parking lots, and often drown in the process.
During those seasons I keep my fins, wetsuit, mask, weight belt and a Spare Air bottle in the car. I'd hate to be needed and not be prepared.-- normzone, Nov 15 2007 Many regrets for your friend's daughter. I must agree with Twizz, and Jhomrighaus. A friend of mine once described power windows as "A dramatic step backwards in technological innovation." They should definitely be done away with. Everyone should know that once the car gets in the water, the electricity will be the first thing to short out. I don't care to consider the number of senseless deaths that have arisen because some lazy car designer thought cranking down a window was too hard for the average american. I will never buy a car with power windows. The ones I've had experience don't even work reliably when the car's in perfect condition.
Good tips are at least coming out of this discussion. I wouldn't have thought to try the trunk. You might also discuss the possibility of forcing the window down by hand. Power windows are notoriously bad at letting criminals do just that.
I very much like the idea of making seat belt buckles that double as window-breaking tools. Most vehicles have at least one more seatbelt buckle than they have side windows. The middle rear seatbelt in particular will rarely be used, and therefore chances of having at least one free for use are pretty good.
You might also consider designing these things so the windows can be forced down manually. The cheap plastic gears can break fairly easily, so with a few finger loops on the inside top of the window it should be possible to pull them down in an emergency.
However, this too may not be enough. Existing devices are designed to be swung at the window. If you've just gone off a cliff, chances are you may not feel strong enough to swing as hard as you'll need to break the window, so explosive bolts and spring mounts are an interesting idea.
Oh... You might devise a way to force the passenger side airbag to deploy. When I was in an accident, I discovered that the passenger side airbags come with a pop up lid, which hits the front window hard enough to crack it. It doesn't shatter in most cases, but that might at least help in kicking it out... Or you could come up with some way to use the explosive round in the airbag to crack the windows, but that sounds like a very dangerous idea.-- ye_river_xiv, Nov 15 2007 If you want to do this, I suspect there's a better way, using leverage to shatter the side window.
Consider the inside top-edge of the door (ie, the below bottom edge of the side window - I suspect it's called the "door cap" but I may be wrong). Now imagine a handhold towards the back end of the door cap. If you grab and pull this handhold (pulling inwards, towards the centre of the car) with sufficient force, the rear part of the door-cap hinges inwards, pivoting about a hinge-point located towards the front of the door-cap. The result is that the front end of the doorcap is forced outwards against the window- glass with considerable leverage. This could be used to shatter the glass.
In other words, turn the door-cap into a lever which can be pulled in an emergency to apply a large force to the window glass. Much better than relying on an impact.-- MaxwellBuchanan, Nov 15 2007 I'm confused about who was driving the car and how the driver survived and how come the driver couldn't save the daughter.
I haven't read most of the previous annotations, but wouldn't it be very dangerous to brake a window open underwater because the water would rush in so fast depending on how deep the car is.?-- BJS, Nov 15 2007 please dear norm, convey to [drememynd] our sadness. this is such a dreadful business and my (our) hearts have poured out to one of our own!-- po, Nov 15 2007 [BJS] Taarna, [drememynd]'s daughter, was alone in the automobile. Apologies if my writing was not clear.
It's extremely difficult to exit the car against the flow of water coming in.
Apparently you want to open an exit, in whatever manner you can, then stay in the car breathing from the air bubble at the top of the car, then take a breath as the air bubble is disappearing and make your way through the exit, now made easier by the lack of water rushing in.
[ye_river_xiv], I like the seat belt buckle idea. It will take a bold automaker to be willing to imply that electric doorlocks and windows are less than ideal. I've heard that they were reluctant to include a spare tire because it implies the ones that come with the care are not perfect.
[MaxwellBuchanan], I like the doorcap idea - probably less complex than designing it into a door. May be more likely to be fouled and become unusable in a rollover accident.
I've also just received an opinion that a rear window may be easier to kick out than a front window, theoretically not being designed to withstand frontal impact.
[po], thanks. I'll let her know.
I plan on taking this up with some fire fighters and getting their input as well.-- normzone, Nov 15 2007 //May be more likely to be fouled and become unusable in a rollover accident.// I don't think so. COnsider two ways in which the door might become deformed. First, in a rontal impact, the doorframe may be squashed front-to-back, in such a way as to prevent the door opening. This could potentially jam the lever if it extended right to the rear of the door- cap, but not if it stopped short by an inch. Second, the door may be caved inwards - but anything sufficient to foul the lever would probably also shatter the glass, which lies in the same plane as the lever.
Also, this levery device could be built into the door-cap (ie, you effectively just grab a handhold on the doorcap itself, and pull it inwards) - no need for any obtrusive hardware. Since you very rarely have cause to pull inwards on the inside of the doorcap, this wouldn't interfere with the normal operation of the door.-- MaxwellBuchanan, Nov 15 2007 [MaxwellBuchanan], you make some good points, but I hope I'm never in a rontal impact.-- normzone, Nov 15 2007 I was a little bit confused only because you said she was young, 'cause in most places it is illegal for youngins to drive, so of course it is more likely that she might have an accident, especially if she was driving illegally.-- BJS, Nov 15 2007 Young by how much opportunity she'd had to live - Nineteen. I watched her learn to drive, she did fine.
I'm guessing maybe fell asleep or dodging an animal on the road.-- normzone, Nov 16 2007 Hi it's me. It seems that in this this discussion of abstract what-ifs there are people who want to know details - so that they can imagine how the ideas might have been applied in my daughter's case.
She was 19, and she was a good driver. She was not speeding, but it was dark and raining, probably foggy on a deserted two lane road.
The car rolled over, and landed upside down in a creek at the bottom of a ditch. The doors wouldn't have opened because the sides of the ditch were in the way. Manual doors wouldn't have helped.
The rear window was inaccessible because the back of the roof had been caved in by a rock on the way down.
And there was no question of time to think because windows were already broken, the back window, the driver's side window, but exit was blocked by the sides of the creek.
The water was rushing in and the only window that was really a possibility was the windshield.
The water was just deep enough to completely fill the car, and not leave air pockets for her.-- drememynd, Nov 16 2007 what [po] said-- pertinax, Nov 16 2007 A note on the oft-repeated "trick" of letting the car fill with water so the pressure equalizes, making opening the door possible.
It doesn't work.
The problem is the, even when the car fills completely, if it is still sinking, the pressure is still not equal. Water density increases with depth, and the pressure inside and outside will only equalize once the car stops sinking, i.e. some time after it hits the bottom. Until then, even when it's full, the pressure inside will be less than outside, and the difference is large enough to prevent opening the door.
This has been verified experimentally on both the British TV show Top Gear and the American TV show Mythbusters. Both shows reached the conclusion that your best bet in the event of driving into a lake is to open the door as soon as possible, before the water level gets too high to make this possible.-- 5th Earth, Nov 16 2007 Damn. I've been avoiding asking for details until you were ready to share. Thanks.
That pretty much reduces it down to aftermarket explosive bolt retrofit kits.-- normzone, Nov 16 2007 [normzone] the explosive bolts could not have helped in this tragedy. As stated the car was lodged in a narrow ravine or creek bed. The doors could not be opened. Perhaps a shaped charge integrated into the perimeter of the windshield mounting just inboard of the perimeter seal could have been triggered by the shock and rollover to sever the windshield from the car entirely. Though from the description it sounds as if there were no good options in this situation. She may not have even been able to move let alone escape in the cold water. The only other option would be some type of rescue breather that might have allowed her to breath until help could arrive.
Our deepest regrets for your loss [drememynd] and our deepest thanks for sharing the details of this sad event. Information is the seed of wisdom.-- jhomrighaus, Nov 16 2007 This is an extremely sad discussion, not being at all hypothetical. But really, how can you go wrong with a small tube of canned air with a regulator velcroed under the dashboard? It would give you time to think without panicking, probably the most important thing in any emergency.-- GutPunchLullabies, Nov 16 2007 Ceramic, such as that found in spark plugs, works best against glass, security glass or normal. Place the device in the gear lever head (automatic/manual). Detachable in case of emergency. None of this means anything, however. My thoughts are with you in this dark hour.-- 4whom, Nov 16 2007 [drememynd], deepest sympathy for your great loss. I shall give my daughter an extra hug tonight.
[5th Earth] What the heck? /Water density increases with depth// That's just wrong. Google that phrase and read carefully.
Water density increases SLIGHTLY with lowering temperature, which generally occurs with increasing depth, but thats as far as it goes. A lot of folks think that density increases greatly with depth, and that sinking ships only sink so far, but it ain't true.
Once a car is completely full of water, the pressure inside will be equal to the pressure outside. The pressure will also equalize if there is a bubble of air in the car, as the bubble of air is compressed. (If you are breathing from that bubble, you will need to exhale on the way to the surface.)
IF there is a bubble of air in the car, AND the car is still sinking, AND the holes that allow water into the car are small, then yes, there will still be greater pressure on the outside of the car. But if the car is FULL of water, the door will open.-- baconbrain, Nov 16 2007 I thought the weight of the water was what made the pressure, in which case the pressure is entirely dependant on depth.
EDIT - but that's not what he said. I think he meant pressure.-- theleopard, Nov 16 2007 Pressure is dependent on depth, yes, but not the density. Water is, generally, incompressible. So the pressure inside a car full of water will be the same as that of the water outside. You can get out.
Darnit, I have to go work.-- baconbrain, Nov 16 2007 I would like to focus, for a minute, or an age, on dememynd's loss. There is a great body of thought residing here at the bakery, and nothing we can do, or say, take away your loss. ________________________ Sometimes, I feel Like I am living at the edge of the world Its just the way I smile, you said. ~ Plainsong (the Cure)-- 4whom, Nov 16 2007 [Baconbrain] Error noted, pressure was the correct term, and what I meant. I want to clarify as well: The doors can be opened *eventually*, once the car has hit bottom, is completely flooded, and has had several moments to completely equalize. However, this process can take a long time after the point when the interior floods over the driver's head, and, it would seem in tests, will not happen at all until the car stops sinking.
I've just linked to the Top Gear Episode where Hammond tries to get out of a sinking car. He is unable to open the door until after the car touches bottom. This doesn't happen until well after he has had to use the emergency air supply.
I was unable to find the original Mythbusters segment, but I found a later clip testing a different sinking car myth. Note Adam (the guy in the car) does not even attempt to exit until the car hits the bottom--this is because in previous tests, they had established that opening the door was impossible until this point.
I stand by my statement: In two independent experiments, it was shown that the doors in a sinking car can only be opened at two points: Before the doors are totally submerged, and once the car hits bottom and stops sinking. You can in theory wait for the car to fill and equalize, but in deep water you'll drown first.-- 5th Earth, Nov 17 2007 Yeah, the pressure-equalizer thing won't work. If you can survive long enough for the car to have enough water for it to work, you probably have gills or something. Personally, I am worried about the pressure. If you shatter a glass with a great amount of pressure on one side, dangerously sharp shards of glass will fly at your face. And that would make escape pretty hard. My idea would be to have emergency air-canisters in cars/in purses. If you get submerged, you can get a few more breaths. This would also be helpful in horrible crashes and similar situations. + for the sentiment.-- Shadow Phoenix, Nov 18 2007 Okay, thanks for checking and clarifying. I was mostly being pedantic, and shoulda let it go, but couldn't bear the thought of someone doing the wrong thing for any reason.
How about a pressure equalization hatch built into the car? Something that blows out or breaks to let water in fast, maybe under the back seat. The window could be made shatterproof, that way. The door will open as long as the door locks release.
Hmm, or how about a big air bottle that pressurizes the inside of the car? That'd give you air and equalize pressure so the doors can open. (If you could fire the airbags, you'd get pressure, but non-breathable gasses.)-- baconbrain, Nov 18 2007 My condolences to [drememynd].
I think, to be honest, that this comes down to the fact that there are more ways to have accidents than there are to prevent them. If you had devices to prevent every conceivable kind of accident, then an inconceivable accident would happen.-- MaxwellBuchanan, Nov 18 2007 "Inconceivable!"
"You keep using that word -- I do not think it means what you think it means"-- normzone, Nov 19 2007 You don't have to strike tempered glass hard to break it. If you take a hardened steel punch and grind it to a sharp point, merely pressing it firmply against tempered glass will break it. This is because tempered glass is under internal tension, and will fail at the tiniest crack. Tempered glass is very hard, but concentrating force on a very small areal will cause a tiny failure that will make the entire thing break.
So there is no need for explosive bolts to break side glass; a sharpened, spring-loaded nail set (like in the idea) will do the trick.
If the question is where to put it, the logical place would be to hide it in the door behind the panel. About a fourth of the glass of a car window you never see, because it is attached to the mechanism inside the door.
If the question is how to trigger it, I would say use a mechanical pressure switch. When the switch is under water, it triggers the punch, which breaks the window. Or maybe a small sodium trigger device if you could shield the device from incidental water contact. Or a combination of both. (a certain water pressure activates valve, releasing water into a chamber with a small amount of sodium, which triggers punch).
As for the windshield, I think the solution may be found in older trucks which had a big floppy gasket that held the windshield in.
The gasket was HC-shaped in cross-section. The bottom of the H held the glass. The top of the H held the interior edge of the window hole. When a round spline was inserted in the C, the whole thing tightened up and held the window in.
It was often difficult to get the spline in, but it was super easy to get gasket-installed windshields out. Just pull out the spline and the windshield would practically fall out.
If the spline was reactive to water in some manner, and was on the inside of the car rather than the outside, you would have a windshield that would fall out or that could be easily kicked out when it got wet on the inside.-- nomocrow, Nov 19 2007 "[...] dangerously sharp shards of glass will fly at your face". I'm not sold on that. One of the beneficial properties of tempered glass is how it breaks. It does not break into long sharp-edged shards. It breaks into little chunks.
Mind you, I'd prefer not to have those chunks flying at my face at high speed, but if you're talking about the pressure outside being caused by water against the window, they'll be carried in with water when the glass breaks making them unlikely to do major damage. I think the spring loaded punch would be a very good option.
What is it about the electrical workings that would prevent an electric window from being rolled down when the car is submerged? Did Mythbusters or Top Gear test that? Assuming the electrical system remains largely intact and the doors aren't smashed in from the sides, what could be done to insure that the windows would still work (assuming that they ordinarily wouldn't)?
Just because the electrical system is submerged doesn't mean there's no possibility of running the windows. Unless the water is extremely conductive, I'd expect the battery to still be able to supply current for a time.
I assume that relay contacts are one of the most likely points of failure. Easy enough to solve with solid state relays, transistors, bigger wire directly controlling the current to the motors, etc.
Brushes in a brush type motor might be another potential point of failure. But, being in the door, some of the motors I've seen are sealed enough that they'd probably operate for a minute or two before getting water in them. Liquid surrounding the rotor doesn't necessarily mean the motor won't run. Some fuel pumps actually suck fuel through the innards of a permanent magnet motor, including the commutator & brushes, for cooling.-- half, Nov 20 2007 They generally short out after the car is in the water for a few minutes.-- nomocrow, Nov 20 2007 [half], when Top Gear tested the car, they did try rolling down the electric windows--no go. The electrical system goes berserk more or less immediately after hitting the water, at least in the car they tested.
Mythbusters tested both manual and power windows, both of which failed, but for a different reason--the exterior pressure on the window mashed it against the frame of the car, creating so much friction it couldn't be opened. However, they tested out of water, with no pressure on the inside, and weights on the outside to simulate pressure. Once the car flooded, it might be a different story, for manual windows anyway.
On their website, Mythbusters noted that "power windows can withstand immersion in fresh water for prolonged periods and still function", but don't say how they tested this, and there may have been some flaw. Note this disagrees with what Top Gear found. I know electric motors work fine under water, but some other part of the system might fail--blown fuses or something.-- 5th Earth, Nov 20 2007 I imagine the failure would have something to do with the electronic control of the windows. I'd be willing to bet that the windows in my ancient Mercedes Benz, which has nothing other than good ol' fashioned switches in the circuitry would work for quite awhile under water. Short of a, uh, short taking out the fuse, there's not much there that would fail in less than a few minutes.
All in all, I don't think there's a much simpler solution than the spring loaded punch (link) for eliminating the door glass. The little hammers seem to work okay, but it seems to me that the punch could be actuated under a lot more less-than-ideal circumstances than the hammer.-- half, Nov 20 2007 Actually, you could integrate this into the hand brake, a la the "Bubble Buster" <link>. But, [+] on your idea.-- Klaatu, Nov 20 2007 [half], doesn't submerging the battery automatically short it out? Water being conductive between the two terminals and all that?-- normzone, Nov 20 2007 I had the opposite problem once: rolling up all four windows during a sudden downpour, I blew a fuse. After that I bought a car with manual windows.-- ldischler, Nov 21 2007 I wonder why cars can't just have both.-- acurafan07, Nov 21 2007 +-- k_sra, Nov 21 2007 I just want to say thank you to all the halfbakers who have expressed their sympathy and support for me, my friends and family, and all those who knew and loved my daughter.-- drememynd, Nov 27 2007 Drememynd mentions that the car flipped over, crushing the windows... so while some of our ideas may be good, I suspect they would not have helped in this situation.
It occurs to me that many cars have very little material or parts in between the floor of the car and the road itself. Perhaps it would be possible to make some sort of escape hatch out of the floor boards.
Such a safety feature might be easier to market, since cars which flip and trap people under the crushed roof are somewhat more common than cars which land in water of any kind.
This would of course be a totally different solution, and not necessarily better, since to open under water, they would have to move inward, and be difficult to get out of the way once opened.-- ye_river_xiv, Nov 27 2007 No, we've just come back to explosive bolts again. I've never used them in anything before, and I'm just itching for the chance to try it.-- normzone, Nov 27 2007 [drememynd] My thoughts stay with you. How can a part feel so much more than the whole? How can THE part not be missed?
"And the temperation of all things proceeded therefrom, and the superior and inferior worlds were mitigated."-- 4whom, Nov 29 2007 Having just stumbled across this, I'll start by saying what a horrific thing to happen to anyone, and my heart goes out to [drem] and those that knew and loved her daughter.
.. Reading through the suggestions above - I think many are missing the first and second real impediments to escaping a rolled and/or submersed car - and that is the seatbelt (which will be nearly always jammed) and the now-inflated airbags, which probably did a great job of preventing you from shattering your skull, but are now seriously hindering your escape efforts.
I drive offroad *very regularly, in an extremely remote area, whereby in some tracks, the next car may not come along for days, or even weeks. I therefore need to be self-reliant for all things. There are many water crossings that I regularly go through, some with dropoffs downstream that could easily fit my whole car should I roll over - and so I "go prepared" for this possibility. I have escape tools strapped to the inside of the sun shades of the front seats, and also in the pouches behind the front seats (accessible from the back seat). These excape tools combine a seatbelt cutter, glass breaking hammer, and I add a sharp edge for shredding airbags myself. They're 440 stainless and will last forever, or until needed. I aslo keep a maglite torch with integral glassbreaker rear cap immediately to hand in the drivers side door pocket - just in case (makes a pretty capable elf defence tool with the side handle and strike bezel as well).
I've not had to use my escape tool in anger, but have practiced a few times on wrecks - It went through the window like a treat and the seatbelt as well.
A few years ago there was a rollover in the town I live in where the passenger was burned badly by not being able to escape due to a jammed seatbelt and no blade handy. Since then I buy them as gifts for my friends.
Last note - I will never embark on a water crossing without first rolling all of the windows down. I see people do the opposite all the time and can't imagine taking so stupid a risk.-- Custardguts, Jul 17 2012 Was going to post this myself, I see it's already been suggested. This really needs to be done. Little emergency handle covered by a red "Lift in case of emergency only" cover and a handle that says "Pull to break glass".
I'd add there should be one you can retrofit yourself so you know exactly where it is if you need it and further, you know it won't be knocked off where you stored it during a crash because it's permanently attached right next to the window.
Easy to make, easy to attach, I'd put one on each family car myself if they were available.
I'll add that the retrofit idea might be better because people will be more likely to know what it does having installed it themselves. Some might see the "Pull to break glass" lever and test it to see if it works if they're not familiar with it.-- doctorremulac3, Feb 24 2023 random, halfbakery