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Discussion Starter · #1 ·
A good friend of mine just got rear ended in his S550 this past weekend by a 745. ..... his s550 suffered about $9-$10k worth of damage based on initial estimate from his insurance. The bimmer was out of commission after the accident, front end pushed in....undrivable and had to be pushed to the side of the road.

according to my friend, the bimmer driver got a bloody nose and the airbag didn't deploy so the other driver was pissed and said he would contact BMW about that....so that got me thinking, is there a way to periodically test the airbag system? or it's so well designed that it can't fail which certainly is not ture.
 

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Well not sure but was your friend going a certain speed. Dont think airbag will deploy if your going 10 mph it may be a certain speed or if impact was hard enough to break sensors in bumper im sure something has to happen before airbag will deploy.
 

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wow are you serious? malfunction for a safety issue? This is something BMW should consider about.
 

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Discussion Starter · #6 ·
The reason I didn't mention speed in the original post is because no one can say it for sure. My friend was brake hard to stop and the bimmer just slammed into his car. From the damage described, which is the only evidence of seriousiness of imapct, I would think the bad should be deployed....But all those defeats the purpose of the post, how do you know if the airbag is working properly. that's the one thing you really don't want it to fail when/where it really counts....
 

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The reason I didn't mention speed in the original post is because no one can say it for sure. My friend was brake hard to stop and the bimmer just slammed into his car. From the damage described, which is the only evidence of seriousiness of imapct, I would think the bad should be deployed....But all those defeats the purpose of the post, how do you know if the airbag is working properly. that's the one thing you really don't want it to fail when/where it really counts....
was the car creeping or was it going like 50mph or 60mph?

its easy to tell between a 10 mph accident and a 50 or 60 mph accident, right?
 

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Discussion Starter · #8 ·
was the car creeping or was it going like 50mph or 60mph?

its easy to tell between a 10 mph accident and a 50 or 60 mph accident, right?
I think they are going at local speed, probalby between 10-40mph....but from the damaged on the 745 I mentioned earlier, ie. front totally pushed in, won't start, undrivable, had to be pushed to the side...i am thinking it's got be more than 10-20mph...and the S550 suffered closed to 10k damage and that's mainly in the trunk, bumper area, which are probably the esaist area to fix in the bodyshop, speaks for the severity of the crash.
 

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A good friend of mine just got rear ended in his S550 this past weekend by a 745. ..... his s550 suffered about $9-$10k worth of damage based on initial estimate from his insurance. The bimmer was out of commission after the accident, front end pushed in....undrivable and had to be pushed to the side of the road.

according to my friend, the bimmer driver got a bloody nose and the airbag didn't deploy so the other driver was pissed and said he would contact BMW about that....so that got me thinking, is there a way to periodically test the airbag system? or it's so well designed that it can't fail which certainly is not ture.
It is VERY HIGHLY likely that the BMW was a "salvaged" car or otherwise compromised (e.g. previously wrecked and not correctly repaired) otherwise the airbag would have properly deployed. This is getting to be more and more common as the prices on these things drop (lot's of fraud going on). The guy "thinks" he is getting a great deal UNTIL something like this happens and he learns ONLY THEN that he bought a POS that likely does not have any warranty on it AT ALL. It's most likely NOT a BMW issue but rather an >O< (between the ears) issue
 

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the srs does a self check every time that you key up and turn the car on. there is no 'check' per se other than this self check.

if the vehicle was a repaired vehicle with 'dummy bags', then i believe the srs has to be turned off and the bulb removed (not 100% sure though, and it most likely will vary by state law on this aspect).

other things that could affect srs deployment would be the use/non use of seatbelts, g force of the impact not surpasing the threshold, or the system being shut down due to failure of a self test (in which case, the bulb should have been on constant), or even a blown bulb (which would hide the fact the system is inoperable due to lack of ilumination).

without actually looking into the recorded data, there is no way of knowing what the facts of the incident are.


df
 

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Generally you have to have a 30 MPH speed change for the airbags to deploy and there are usually a number of sensors in the front that have to be triggered as well. A 30 MPH speed change is quite a bit. All vehicles have to meet the FMVSS of either a 10 or 15 mPH bumper impact, don't remember off the top of my head but there are standards that vehciles have to meet for frontal or rear end impacts.

YOu can't always look at the damage and tink the airbag should have gone off. Modern cars are now designed to crumple and give which decreases the "impulse" time and absorbing the energy instead of transferring it to the occupants. That's also why airbags are a supplemental restraint in addition to seatlbelts. I'm curious to know if the person who had the bloody nose had their seatbelt on. IN theory if your belted theres nothing for you to hit since the seatblet will stop you.
 

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the srs does a self check every time that you key up and turn the car on. there is no 'check' per se other than this self check.

if the vehicle was a repaired vehicle with 'dummy bags', then i believe the srs has to be turned off and the bulb removed (not 100% sure though, and it most likely will vary by state law on this aspect).

other things that could affect srs deployment would be the use/non use of seatbelts, g force of the impact not surpasing the threshold, or the system being shut down due to failure of a self test (in which case, the bulb should have been on constant), or even a blown bulb (which would hide the fact the system is inoperable due to lack of ilumination).

without actually looking into the recorded data, there is no way of knowing what the facts of the incident are.

df
That is true, the SRS system does a check to make sure that the components are still there (undeployed, however beyond this there is a whole lot unknown to the system (whether the deployment substance is still good, etc). The bag could have been defective in some way and the SRS system couldn't have picked it up.

Also SRS is being thrown around here, does anyone know what it is? SUPPLEMENTAL Restraint System; it's designed to supplement the seattbelt, not designed to protect your body for even the slightest thing.

airbag deployment is not guaranteed ! which is tuff to swallow ! i've been to quite a few high speed accident's where the airbag has not gone off ! usually resulting in a skull sized hole in the windscreen !!
Airbags are never guaranteed to go off, it's a chemical reaction, odium azide (NaN3) with potassium nitrate (KNO3) to produce nitrogen gas, that inflates the bag. If any of these chemicals was not released in the correct proportions or one of the chemicals was contaminated, the bag would not have gone off.

Generally you have to have a 30 MPH speed change for the airbags to deploy and there are usually a number of sensors in the front that have to be triggered as well. A 30 MPH speed change is quite a bit. All vehicles have to meet the FMVSS of either a 10 or 15 mPH bumper impact, don't remember off the top of my head but there are standards that vehciles have to meet for frontal or rear end impacts.

YOu can't always look at the damage and tink the airbag should have gone off. Modern cars are now designed to crumple and give which decreases the "impulse" time and absorbing the energy instead of transferring it to the occupants. That's also why airbags are a supplemental restraint in addition to seatlbelts. I'm curious to know if the person who had the bloody nose had their seatbelt on. IN theory if your belted theres nothing for you to hit since the seatblet will stop you.
very true about the speed, I nearly forgot about that!

also very good comment on not judging the safety of a car by the way it crumples. As said before newer cars (esp ACE constructed cars) are designed to crumple to absorb the impact of the crash so the occupants do not feel as much of a sudden deceleration (which is what really kills you). However the cars are constructed to keep the passenger compartment safe as well (non-crumple zone) which should stay intact during the whole ordeal. I wouldn't be surprised if the driver of the 745 had his seat and wheel set incorrectly and didn't wear a seatbelt (no idea how he could have done that, my 7 chimes the brains out of you)
 

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its not the speed that kills you, suddenly becoming stationary... thats what gets you
Actually you are correct. What really kills you is comonly referred to as an aortic dissection. Basically your aorta become separated from your heart and well doesn't take a rocket scientist to figure out what happens next.

When you have a collision its actually a series of smaller collisoins. For instance in a rear end type collison the first one is the cars hitting or your car colliding with an object. The second is your body colliding with the seatbelt and the third, and this is the killer, is your internal organs colliding with your body. If your traveling at 50-MPH when you hit your body is going to be propelled at 50-MPH and your organs are actually going that speed as well. Thats whats know as the impulse time. The airbag and seatbelts are designed to increae that impulse time to slow eveything down to prevent the internal injuries.

Also keep in mind any loose itmes in your car that get flung about are also going to be traveling at that speed as well. Just for all those people that like to keep objects sitting on top of the rear deck area.
 
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