I was reflecting on this the other day, and thought I would get some opinions on this issue. About 2 years ago, I had a 99 SR5 4Runner and was on the highway coming home when someone came hurling across the median headed directly for me. I quickly swerved out of the way (going a constant 70 MPH), however I underestimated the sensitivity of the steering wheel and went off the side of the road over a good 5-6 foot drop and flipped the truck head over heels 3-4 times before stopping (or so they say...I can't really remember). I never even had a chance to hit the brakes. No one was hurt (I was the only one in my truck) and the only injury I sustained was a broken collarbone due to the seatbelt (damn thing was strong as hell ).

Anyway, I was curious to know why the airbags did not deploy. The truck was completely torn up (totaled), with all 4 tires blown out, and the roof heavily bent in on the back (but hey, it kept me alive). I was just curious as to what everyone thought about why the airbags didn't deploy. I don't know if they would have been more harm than help in this incidence, however you would think with the truck undergoing that much trauma, they should deploy.

Any thoughts?

BTW- I'll try to dig up some pics of the truck before and after the accident to show you how well (considering) the truck held up. Toyota makes one hell of a strong and safe truck...that's why I bought another one as soon as the insurance company cut the check.

 

The sensors that deploy the air bag are designed for a frontal impact. I believe thats the only purpose for them.

Jay

 

Yes, this is true. I have recently complete a VRT (Vehicle Rescue Technician) class and we learned a whole heck of alot about air bags. Basically the airbags are to slow the head impact and prevent the head from going through the windshield, hitting the dash, etc., and prevent neck injury. This safety is only capable if the seatbelt is properly worn. The reason that the airbag did not go off is because the front did not sustain an impact that was strong enough to deploy the airbag.

On a side note, just because the airbag did not deploy and the vehicle was damaged, does not mean the airbag is inactive. Even after the battery is disconnected, the airbag remains active for close to an hour. The only way that you can disconnect the airbag for sure is to remove the airbag module in the vehicle. This should not be done by anyone other than trained rescuers or technicans at a shop. Basically the best thing that you can do is to get out of the vehicle, if you are able to, or just assume that the airbags are going to deploy and position yourself so they will not impact you and injure you. Please be careful, airbags are very dangerous.

I hope this helps and I am glad to hear that you were not "seriously" injured! :fireman:

 

Hey guys,

Thanks for the replies. The only thing that stumps me is that when I went off the highway, the first thing that hit the ground 5-6 feet later was the front end. It dropped like a ROCK.

 

HUH, that is strange. The only thing that I can think is that they were malfunctioning or maybe because you were falling, they some how cut out. I don't know what to tell you now. Sorry! :fireman:

 

I'm not an airbag designer, but there are an awful lot of variables involved. The designers are trying to make them so the airbags don't go off too soon or to late, don't go off unless the collision is hard enough to need them , trigger only when you hit or are hit in the front (at least for the front ones), etc. etc. They're certainly not perfect. If the front hit such that a lot of the force was up instead of directly into the front, it might not have been large enough or with the right kind of "pulse" to trigger them. It sounds kind of tricky and compromises certainly have to be made.
Alan

 

I have also heard that if the impact is sever enough it could actually damage the airbag sensors and disable them not allowing the airbag to deploy......I don't know how true this statement is but it's what I heard....

 

Thanks for all the input! It was actually a good thing that the airbags did not deploy just because of the nature of the incident. I'm not by any means complaining...the 4Runner kept me alive and safe. I was just curious as to the technical aspects behind it. It could have turned out alot differently if I was driving any less of a vehicle.

I initially bought the 4Runner for it's looks and features (first was the 99), but now, because of additional obvious reasons, I am hooked to the 4Runner for life.