Question about air bag deployment.

Ok so this is the scenario:

Two people drunk in a 2011-2012 Mercedes E-Class go off the road at a high rate of speed, bounce off a couple trees and a boulder, roll the car over and slide to a stop upside down.

Neither people were wearing their seat belts.

Should the air bags have gone off?

The airbags did not deploy and it is being said that because they did not have their seat belts on, the car would not have deployed the airbags.

I feel that is incorrect.

airbags are controlled explosions in an already very un-controlled situation (any crash).

I see the logic to not add more explosions and possible impacts to a crash when the occupant's positions' in the passenger compartment are now largely unknowns (if they were wearing seatbelts, you could probably make a semi-accurate guess as to where the occupants are; no seatbelts, no accurate guesses).

Without having a look at the logic the MB airbag computer uses to determine when to deploy the airbags, it's hard to say if they should have deployed or not.

Seems like they should have gone off.

Yes, they are more effective with the belts on, but the entire reason they are forced on cars are to save people who don't wear their seat belts.

Back in the 80's, we had belts that were on rails, belts attached to the doors, OR an air bag. Then two air bags for people who don't use the belts.

Now they don't go off if you don't have the belts? that's not how I remember them being in cars.

Absent a solid frontal impact, I could see the airbag control logic being much as described by rcutclif above.

MCarp22 wrote: Without having a look at the logic the MB airbag computer uses to determine when to deploy the airbags, it's hard to say if they should have deployed or not.

This. It's possible the computer was programmed to not activate the airbags if the seatbelts weren't in use, but that would be stupid.

Stupid from a legal liability and safety aspect, although I do like a car that says "Oh you don't want any seatbelts huh? Guess you're Superman, I'll disable the airbags so that they don't muss your hair."

My experience with late model Nissans is that if the occupant sensor in the seat doesn't sense a load/weight in the seat at or above its factory determined threshold, it will not deploy the air bag, regardless of if the seat belt is buckled or not.

If the occupant isn't buckled in, and is therefore thrashing about in the car, as apposed to being held firmly in the seat by the seat belts, then there's a good chance that there wasn't enough weight in the seat for the SRS computer to justify deploying the air bags.

I am all for making no effort to enhance accident survivability for people who refuse to use a seat belt. Kuddos to whoever wrote that program.

alfadriver wrote: the entire reason they are forced on cars are to save people who don't wear their seat belts.

That reasoning isn't cited in FMVSS 208 at all. Can you provide me with a link/document discussing where airbags being mandated is intended for unrestrained occupants?

This is not the first time I have heard of this, just never really looked into whether it was true or not.

Did they ever hit anything hard with the front of the car? I buy cars all the time from insurance salvage, most of them with front end damage, and most of them with intact air bags. It takes a pretty good smack to light one off.

MCarp22 wrote:

alfadriver wrote: the entire reason they are forced on cars are to save people who don't wear their seat belts.

That reasoning isn't cited in FMVSS 208 at all. Can you provide me with a link/document discussing where airbags being mandated is intended for unrestrained occupants?

No, I can't. But back in the 80s when the whole air bag thing really took off, there was lots of interest to improve accident survivability- either by forcing the driver to use a belt or an airbag. So cars either had one system or the other.

And since air bags are call Suplamental Restraint Systems, SRS, they are there to do that.

That's why I don't understand why airbags would not go off without the belts. They are there to help, and a beltless human should be factored into that.

Because if a belt less human is too close to the exploding airbag, some lawyer will argue the airbag killed him instead of his own stupidity in not wearing a seatbelt.

Streetwiseguy wrote: Did they ever hit anything hard with the front of the car? I buy cars all the time from insurance salvage, most of them with front end damage, and most of them with intact air bags. It takes a pretty good smack to light one off.

Well considering they bounced the car off two trees and a boulder at god knows how fast and rolled it over, I would expect something to fire off whether it be front airbags, side restraint, or head restraint, but nothing fired off at all.

alfadriver wrote: That's why I don't understand why airbags would not go off without the belts. They are there to help, and a beltless human should be factored into that.

Perhaps they did factor into that. The way it's supposed to work is decel - airbag inflates - occupant hits airbag. I could see how they might decide above a certain rate of deceleration with an unrestrained occupant, the sequence might be decel - occupant hits airbag - airbag inflates, which would result in further injuries for no benefit.

bigdaddylee82 wrote: My experience with late model Nissans is that if the occupant sensor in the seat doesn't sense a load/weight in the seat at or above its factory determined threshold, it will not deploy the air bag, regardless of if the seat belt is buckled or not. If the occupant isn't buckled in, and is therefore thrashing about in the car, as apposed to being held firmly in the seat by the seat belts, then there's a good chance that there wasn't enough weight in the seat for the SRS computer to justify deploying the air bags.

This. A recent Mercedes like that should have "intelligent" airbags that deploy depending on the weight of the individual. I'm guessing that when the car left the road at high rate of speed, the pasengers bottoms were no longer in their seats, or light enough that they were determined to be kids. Hence, no airbag deployment.

I will not shed a tear on drunk drivers that do not wear their seatbelts. I will when said idiots sue Mercedes and win because Mercedes wasn't good enough at protecting them from their own stupidity...unless Darwin already took care of them?

alfadriver wrote:

MCarp22 wrote:

alfadriver wrote: the entire reason they are forced on cars are to save people who don't wear their seat belts.

That reasoning isn't cited in FMVSS 208 at all. Can you provide me with a link/document discussing where airbags being mandated is intended for unrestrained occupants?

No, I can't. But back in the 80s when the whole air bag thing really took off, there was lots of interest to improve accident survivability- either by forcing the driver to use a belt or an airbag. So cars either had one system or the other. And since air bags are call Suplamental Restraint Systems, SRS, they are there to do that. That's why I don't understand why airbags would not go off without the belts. They are there to help, and a beltless human should be factored into that.

i would argue that the word "Supplemental" means they are used with seat belts, not in place of seat belts. and i could totally see why you wouldn't want them firing off if you didn't know where the occupant was. but i can also see how plaintiff attorneys will be falling over themselves to sue the vehicle manufacturer.

ThunderCougarFalconGoat wrote: Because if a belt less human is too close to the exploding airbag, some lawyer will argue the airbag killed him instead of his own stupidity in not wearing a seatbelt.

Instead of that, you get the driver and passenger going through the windshield.

Yea, I think an airbag without the belt is better.

alfadriver wrote:

ThunderCougarFalconGoat wrote: Because if a belt less human is too close to the exploding airbag, some lawyer will argue the airbag killed him instead of his own stupidity in not wearing a seatbelt.

Instead of that, you get the driver and passenger going through the windshield. Yea, I think an airbag without the belt is better.

So it's basically a real-life version of the airline crash position conspiracy theory?

In reply to AngryCorvair:

again, the alternative is that the front seat occupants colide with the hard stuff in front of them.

Suplamental back in the 80s meant that it was an alternative to the belt. Preventing the collision between the head and the windshield.

GameboyRMH wrote:

alfadriver wrote:

ThunderCougarFalconGoat wrote: Because if a belt less human is too close to the exploding airbag, some lawyer will argue the airbag killed him instead of his own stupidity in not wearing a seatbelt.

Instead of that, you get the driver and passenger going through the windshield. Yea, I think an airbag without the belt is better.

So it's basically a real-life version of the airline crash position conspiracy theory?

?? I don't understand your point.

Remember, back in the 80's, not that many people used seat belts. This was way before any state had seat belt laws. But air bags were beginning to be available- so they had to be able to constrain drivers (since passenger bags didn't exist) without the belt.

Since they worked, legislation was passed that car could either have belts that had to be used or airbags. That's why cars had belts on runners or belts installed in the doors OR they had airbags.

So the airbag is programmed not to deploy if the seatbelt isn't in use, because even though the airbag going off is technically preferable to the person going through the windshield, it could harm them and cost the manufacturer big money in a lawsuit later if the airbag causes their injury or death instead of something outside the car.

Sounds a lot like the conspiracy theory that the aircraft crash brace position is meant to kill you so that the airline won't have to cover your disability. Except real.

In reply to alfadriver:

I didn't say it was better, or even smart. But when asking why a car manufacturer did or didn't do something, the answer is probably "because of lawyers".

It would be a lot harder to sue the manufacturer about colliding with the windshield than an airbag in mid inflation. I can see some lawyer advising them to program the airbags not to deploy if the occupants aren't belted in.

In reply to GameboyRMH:

Would make some tin hat sense, execpt that I'm pretty sure the point of the SRS laws in the first place was to prevent deaths when belts were not worn.

In reply to ThunderCougarFalconGoat:

That implies that death is better than injury. Which it never is.