Airbag didn't deploy.

[montero1]

My neighbor has an '06 GMC Envoy. Rear-ended a trash truck going 30+ mph, no airbag. Seat belt didn't lock either (unless he's lying and wasn't wearing it). Does an impact need to be smack dead in the center of the front bumper for it to deploy? Looks like most of the impact was to the right side of the front license plate. He's talking about sueing GMC, I told him fat chance, too many variables here. Truck has 107,000 miles on it also.

 

[Colt45ws]

Was it operational beforehand? ie. the airbag light wasnt on?

An impact does not need to be smack dead in the center, but it has to trip more than one sensor to cause it to blow the bags. If only one sensor trips, it will assume a faulty sensor and lock out the airbag system. But any impact to the frontal area that causes metal to be deformed should trip multiple sensors.

 

[Unearthed]

My 2003 Sentra was clipped in the rear while I was going about 65 on the highway. I lost control and hit the middle guardrail head on. No airbag. I was told it was because of the height of guardrails the sensors go under them and the impact point is too high.

 

[NHGUY]

Its usually a matter of G force,or decelleration.However,you hear a lot about airbags not deploying in a lot of models.Makes one wonder why they get installed in the first place...oh yea,because the Feds mandate it.

 

[leeharvey418]

Airbags aren't set off by crush contacts in the front bumper, they're set off by accelerometers. Before the days of advanced airbags, those accelerometers were literally little more than two contacts separated by a spring plunger - now an accelerometer chip is cheap and reliable enough to do the job. I don't know when the cutoff for advanced airbags was, but being an older platform, I'd bet that the Envoy still has mechanical accelerometers (I'm sure the Sentra did). Either way, what it takes to set off an airbag system is the acceleration along the x-axis (fore/aft direction) exceeding a minimum threshold for a minimum time. It's possible that with older systems, the spring plunger mechanism might bind, especially under a lateral load, but more likely the reason the airbags didn't deploy was because the impacts weren't all that severe. Hitting a garbage truck with an actual impact speed of 30 mph would total any vehicle - most accidents have an impact speed that's in the ballpark of 15-20 mph.

 

[Trav]

I would check there is in fact an airbag installed.
The was a few gangs up here that were garages, when serviced airbag lights came in they would swap the real bag out for a dummy which was more or less just a big block of foam.
The seat belt is easy to test.

 

[bradepb]

You would be suprised at some of the crashes we have had with our little mini-buses that didnt trigger the airbag. Ford and GMC 1 ton chassis, a couple were totalled with no deployment, no injury either.

 

[eljefino]

The airbag controller would remember stuff like the decelleration rate and MPH at impact.

But it most likely wouldn't put it into long term memory if it chose not to deploy the bag. "Just another day".

If it DID remember, it would remember if the seat belt were buckled, if it detected weight in the passenger seat, etc.

On my car the airbag controller, under the handbrake, has the acellerometer(s) and no external parts, just wiring off to the bags and data bus.

 

[Truckedup]

To the OP,was your neighbor injured in the crash? If nothing more than minor stuff he was likely wearing his seatbelt and the impact wasn't severe enough to deploy the bag.
Generally speaking,passengers belted into a modern vehicle will be ok without an airbag in many situations.Airbags are for severe collisions.And we all know an unnecessary air bag deployment can cause injury...

 

[The motor guy]

you were only going 30mph Not fast enough to deploy.

 

[Astro14]

The essential point is this: it's a measure of acceleration (or deceleration) that triggers airbags, not speed of the crash. Because this was an offset (not dead-on) it may not have met the threshold for deploying the airbag, there are different safety/structural standards (validated through crash testing) for offset frontal crashes.

Bottom line: If he is uninjured after hitting a garbage truck at that speed, he should be thanking GMC for saving his life, not filing a lawsuit for systems he doesn't understand...

 

[Doog]

Originally Posted By: montero1
My neighbor has an '06 GMC Envoy. Rear-ended a trash truck going 30+ mph, no airbag. Seat belt didn't lock either


Doubtful he was going that fast. People have a tendency to over estimate their speed. The statistical chances that both the airbag and seat belt tensioner would fail simultaneously are astronomical.

 

[SLCraig]

There is no impact sensors in these actual areas, it works as a sort of inertia sensor, in my Saturns the airbag module was under the column between the gear selector and the rear seat. The airbags should go off if the vehicle is slowed down at a determined rate of speed, not an actual deploy sensor in the front bumper somewhere. It is odd they did not go off, if he is for some reason embelishing the speed he hit the truck, it could just be that simple.

 

[cchase]

Originally Posted By: Doog
Originally Posted By: montero1
My neighbor has an '06 GMC Envoy. Rear-ended a trash truck going 30+ mph, no airbag. Seat belt didn't lock either


Doubtful he was going that fast. People have a tendency to over estimate their speed. The statistical chances that both the airbag and seat belt tensioner would fail simultaneously are astronomical.


I agree. But as mentioned elsewhere in this thread, airbag deployment is a function of vehicle speed and vehicle deceleration. If the qualifications are not met, they won't fire.

That said, if you're wearing a seatbelt I'm not sure why you need a front airbag in the first place.

Suing GMC? Is this like the "sue because I'm too stupid not to crash into things, it can't possibly be my fault" mentality that is so commonplace these days?

 

[Eddie]

We have a winner here. I ran into a truck because it got in my way. Didn't the stupid truck driver realize how important I am.
)

 

[ARCOgraphite]

Deployment depends on deceleration rate. If not enough G-shock then bag wont deploy. Sometimes better than having your eardrums ruptured. In the not to distant past we worked on developing B--ch chip packages for these devices along with tire pressure sensors.

 

[Spazdog]

Originally Posted By: Astro14
The essential point is this: it's a measure of acceleration (or deceleration) that triggers airbags, not speed of the crash. Because this was an offset (not dead-on) it may not have met the threshold for deploying the airbag, there are different safety/structural standards (validated through crash testing) for offset frontal crashes.

Bottom line: If he is uninjured after hitting a garbage truck at that speed, he should be thanking GMC for saving his life, not filing a lawsuit for systems he doesn't understand...


This.

I was on a fire investigation for a vehicle equipped with our IID (Supercharged Grand Prix. Unit was not at fault and recovered intact). The GM rep was there working double duty on our fire and an Equinox accident. The Equinox owner was upset that the airbags didn't deploy and her daughter would be "forever scarred from her bruises"

" her words, not mine.
It was an offset collision similar to the one described above. Looked like the front right wheel had borne most of the impact. He tried in vain to explain the criteria for deploying the airbag but she wanted a big soft pillow to magically appear in front of her young daughter in a collision. I never did get the age or weight of her child. Probably too small to be in the front seat anyway.

 

[Kestas]

Let's talk vectors. The front air bags deploy only if there is frontal deceleration. If the car is hit on the side they won't deploy. Was the vehicle in any way sideways during impact?

 

[ahoier]

Originally Posted By: Unearthed
My 2003 Sentra was clipped in the rear while I was going about 65 on the highway. I lost control and hit the middle guardrail head on. No airbag. I was told it was because of the height of guardrails the sensors go under them and the impact point is too high.
Yep. My KIA Owner's Manual actually had a "picture" of this.....black and white cartoon-ish anyways....explaining this logic.

Yes, if you were to rear-end one of those "jacked up" pick up trucks, riding on 32" All Terrain tires or wahtever they put on them, and the point of impact were, say the "hood" of the car, it would not deploy the air bags.


My first accident, I was at a stop light, and an oncoming driver lost control (hydroplaned in the rain) of their vehicle and front-ended me. I was not moving, but my driver side air bag WAS deployed, even though I was not moving.

Was crazy, cause I could "see" the car coming at me, but no reaction time to "avoid" it, other than throw the trans into reverse and slam the gas Afterall there was no car BEHIND me....but like I said, it all happened so quick.

The air bag didn't do anything I don't think...I had 2 little burns on my wrist where I was gripping the steering wheel that's about it Was crazy, cause I didn't actually get to "see" it deploy By the time I snapped out, it was already deflated...

And I was expecting a Maggie Simpson pillow to catch me




My second accident, I was in the center turn lane, on a 5 lane road (2 lanes, going north and south, and 1 lane in the middle for merging), old lady blew a stop sign, T-boned my passenger side, I do not think my air bag even went off...makes sense though cause that car had sensors in the seat, so the air bag would not go off unless someone was actually "occupying" the seat....even stated in the manual to not keep luggage, bags, purses on the seat

 

[montero1]

.....close but no cigar, Monica. He's not blaming anyone, something came up from the road, cracked his windshield, he lost control, went across four lanes, and rear ended a trash truck. He suffered cuts to his chin, nose, and forehead from hitting the steering wheel.