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-   -   Frontal Crash - Airbags didn't deploy. Why? (https://www.team-bhp.com/forum/road-safety/157842-frontal-crash-airbags-didnt-deploy-why-4.html)

ABS equipped cars don't generally leave skid marks.

From the snap it is evident that the sensor holder is intact. The bonnet has crumpled and folded over the same. How could the airbags deploy when the impact has not reached the sensor(s)?

Airbags are called as SRS (Secondary Restraint Sys), the primary being seat belts. There are a lot of things that have to happen in a particular sequence in a span of micro secs for Airbags to deploy. Unwarranted deployment of Airbags can cause severe damage as explosives are used for deployment as only they can perform the action in such short span of time and the force of deployment has been known to break ribs. Hence some countries ban pregnant women and infants to be in front seat to prevent injuries due to airbags.

The airbags are generally designed for a particular angle of collision and I have rarely seen a deployment after a crash with a pole, car turning turtle or on rear ending a truck or trailer. So I feel in the accident with Terrano that would be the reason for non deployment.

MANY interesting lessons can be learned from this great double-impact video:

First, lets watch the video...

https://www.youtube.com/watch?v=tADvFcj7Cm4

Now, lets break it down:

@ 00:03

• Always indicate a turn well in advance.
• Brake gradually. Sudden breaking increases the chance of you getting rear-ended.
• Check your mirrors when slowing down to a standstill.
• Pay attention, don't speed & don't use your phone when driving (I'm talking to you, white-pickup guy).

From here on is where it gets really interesting...

@ 00:06

• Note that while at a standstill he turns his wheels, in preparation for his upcoming the left turn. This is a mistake!
• When waiting to go across oncoming traffic, you should NEVER turn your wheels until you start to move. Reason: If you get rear-ended and your wheels are turned, you will get pushed into oncoming traffic!!

*BANG* - he gets rear-ended

@ 00:07

• Seat belts are lifesavers.
• Note that the airbag (correctly) did not inflate in this situation.
• Look at the fear in his eyes as he gets pushed straight into an oncoming truck - because his wheels were turned.

*BANG* - he goes head-on into the truck

@ 00:08

• Moment of 2nd impact (frontal) is when the airbag does finally inflate, and correctly so! It's been engineered for situations like this (which are a common occurrence in accidents).
• Note again: Seat belts are lifesavers.

@ 00:13

• Look at his face. Man is amazed to be alive, thanks to modern safety systems and a touch of luck.

@ 00:20

• After an accident, do NOT unbuckle yourself or get out of your car unless you are sure it is safe to do so. Thankfully it was 3rd time lucky for this guy, despite him not looking around properly before unbuckling.

Note that all of the real damage happened in just ~6 seconds!

Just a few additional seconds of correct procedure and safer driving might have prevented a lot of it!

Thanks for an excellent analysis Rehaan.
:OT but...
Amazing how many drivers actually DON'T do that - check rearward traffic before slowing down or changing lanes or taking turns. But it does appear that the driver did a quick head check on his (left) ORVM, but missed the other car coming up fast behind.
True except perhaps in the Indian context.:D Remember those lane cutters who will come up on your left and stop with their driver doors (or their 2-wheelers) 1.5 inches from the edge of your bumper, and THEN wait for their chance to turn right? Well, getting rear-ended with your front wheels straight might just mean you'll end up with your front left wheel on his lap!

Apart from not turning the wheel before moving into the turn, stomp down hard on the brake pedal when stationary. Keeps the brake lights glowing, and reduces forward movement of the car in case of being rear-ended. Applies to stops at red lights too, unless there are a few cars stopped behind you.

Interestingly, old style advanced driving courses said, take your foot off the brake once another car has stopped behind you, so that you stop dazzling him as a matter of courtesy. Current outlook is, safety is more important than a dazzled stationary driver behind you.
This depends on situation to situation. In the event you smell fuel, get out of the car as fast as you can, and help others out too ASAP. Most cars nowadays have impact-sensing fuel cut-off valves, but in case of rear-end damage in a situation like this, rupturing the fuel tank itself is not difficult.

Yes he did! However, like you said, the car behind him was coming up fast and hence was rather far away when he did.

I guess another point can be made that safety isn't just one or two things you do to negate danger, but rather a full system of things that should always be followed. Add to that, unfortunately, it is a collaborative effort between all road users.

Good point. In our road conditions some rules don't carry over perfectly, and it's best to judge based on the situation.

:thumbs up

I think that even in a situation like this, it's better to exit the car only after looking around properly! :)

In most Indian cities, the window of opportunity to make a turn at busy intersections is so narrow that there is no time for you turn the wheels and press the accelerator.

In Bangalore at least, there are a million busy intersections with no traffic lights or cops. Back here, playing chicken (move a bit, make eye contact, move a bit more to see if he stops, hit the brakes if he doesn't, go ahead if he does) works optimally.

So, I had an accident about two weeks ago.

Driving on the Bangalore Mysore highway, just at the end of a curving stretch, a tempo had parked in the middle of a highway and was (supposedly) arguing with a bullock cart driver. (more on this new scam in a seperate post!)

I must have been doing at least 80kmph when I saw him. Too little too late as the vehicle screeched to a head on collision with the rear of the tempo (speed of impact? I don't know.. 50-60kmph?)

As you can see from the pics, the front was quite badly done in. Bumper, radiator, headlights, bonnet, compressor, side panels blah blah are all being replaced. The radiator had been ripped out of its bed and slammed into the engine head. (still not sure if there's any engine damage though)

Had the car towed to VW Mysore.

Now, the airbags didn't deploy. That was alarming enough for me. A full frontal impact and no deployment? According to their own documents "frontal airbags are designed to deploy in moderate to severe frontal or near frontal crashes, equivalent to hitting a solid fixed barrier at 8-14mph or higher. "

But what was worse was when I asked the VW guys about it, they said (im quoting verbatim here) "I don't know why it didn't deploy sir, sometimes it doesn't deploy for a 'semi-major' accident"

What on earth does that mean? Is every car a lottery card when it comes to airbag deployment?

A lot of folks are suggesting I should take them to consumer court and to that effect im waiting for the investigation summary and the final bill to be handed over before making a fuss.

To answer a few thoughts before you ask:

• Yes, I was wearing my seatbelt.
• No injuries, just minor whiplash/neck sprain. Scarily enough I was on my way to pick up my wife and new born daughter to bring them home. *shuddering at the thought of what if!*
• I complained to VW on FB, Twitter etc. Not even the basic courtesy of a call or a response
• I refuse to take the "chalta hai, it could have been worse" attitude that lets these OEM's get away with stuff. If this really is a sensor failure/airbag failure, I want to see what my options are.
• The bill thus far is in excess of 2L. Insurance will cover most of it so thank god for small mercies.

Im in two minds on whether to take action or accept that even though it was a frontal accident, maybe the impact was not enough for the inertia to reach the steering wheel? My head didn't hit the steering wheel or vice versa.

Any thoughts/advise folks?

That is scary.
I don't see why a legal action shall not be initiated against VW of they do not provide a satisfactory explanation or compensation.

First, I'm relieved you're safe and that your wife and new-born baby were not in the car when the unfortunate accident happened. I hope your neck is okay now. It's good that you were wearing the seatbelt, as it could have been much worse if you hadn't belted up.

I hope the other fellows didn't suffer any serious injuries, either. Sorry to see the damage to the car, and to hear of expenses for the repair.

From the pictures, it looks like the car's safety structure did absorb most of the forces when the impact happened, and the seatbelt surely did its job of restraining you and preventing your head or chest from hitting the steering wheel.

As for the airbags not deploying, I don't really know. It may not have been a failure in this case. The impact sensors get the airbag control module to deploy the airbags only when a certain threshold has been crossed. If the forces acting on the impact sensors are less than this threshold, then the airbags wouldn't deploy. One can't call it a failure if this is the case, as it's designed that way.

Perhaps someone with more knowledge on the conditions necessary to trigger airbag inflation would be able to throw more light on this.

Sorry to hear this. Dont get me wrong. The minor scrapes you had as you described also explains why the air bag didnt deploy.

Only two reasons comes to my mind.

1) Faulty sensor which VW should take ownership on. Find if the sensor was replaced or service. Thats not right if they did it without admitting issues. If they are returning the car without touching the AIr Bag sensors, i am pretty sure they are ok with the sensor. Find any trace of work done on the Air bag, wires and sensors.

2) The impact was actually not worthy of air bags. The original statement i made on minor scrapes could have been worse with air bags deploying as its not a soft cotton ball but in reality its like hitting water face up from say atleast 8th floor.

The reason i say is from the pictures the body or the main frame seems to be intact with the major components including bumber, radiator and even the front bonnet taking the impact really well which is exactly what they are meant for.

I may be wrong but you hit the cart in a way and speed that help dissipate the impact and kept you safe with minor scrapes.

Just understand the work that was done for Airbag to get a better understanding.

Now coming to VW. THey are always lazy and take customer for granted. They deserve to explain atleast like how i did with a story instead of remaining silent.

Keep pursuing and invite all your friends to start posting about this in social media. Social shame them as much.

Thanks, my sentiments precisely!

His tempo had a wrought iron beam that took the impact, not a scratch on him (I envy him to be honest!)

Could not agree more. I cant understand whether this is airbag failure or a training/communication issue on the part of the SA. Which is why im hoping fellow bhp'ians will be able to help me figure out which of the two it might be! :)

A great relief to hear you got away unscathed. The crumple zones seem to have worked pretty well. That's why airbags alone aren't enough to keep budget hatches safe as they don't have structural strength like your car. Am sure VW wouldnt want their cars airbags going off at every little bump .At the same time VW needs to be more proactive in reassuring it's customers.

Good point. But now that I've asked them about the airbags what's to stop them from replacing the sensors without my knowledge to limit their liability?

Ive had a crash in the US which was at a far less speed (hit a stationary motorbike from the side while taking a left turn (so you can imagine the speed - 10mph maybe? The airbag went off. And you\'re right, it hits like someone socked you in the chest/face with a bowling ball. But this was far far worse an impact than that and yet nothing. Could it be a case of indian standards for indian cars then? Which is an even bigger issue in that case!

Looking at the pictures, the impact is not severe to cause airbags to deploy. The front beam is intact and has not crumpled. Basically crumple zone is intact. This will equate to no airbag deployment.

Secondly, VW has a very poor design with respect to radiator. The entire radiator assembly which sits on a frame in the front is made of plastic not metal. Any small impact will cause the entire thing to break.

Thirdly, airbags are not meant to deploy easily. Unless impact is very very severe. If they did you would see more injuries. This is because airbags deployment is a controlled explosion. This explosion can cause burns in some cases.