What to do if your airbags don't deploy in a crash

You’ve just crashed your car. You look around, and the airbags have not deployed. Should you sue the manufacturer? Let’s talk about that.

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This issue blipped on my radar because I recently got an email from Teg Sethi.

You probably remember Teg. He’s the guy from the Lemon Jeep video. He bought a Grand Jeep Cherokee. It bit him on the arse multiple times, so he made a hilarious video about that (right).

It got 2.5 million views and struck a real blow for lemon-car afflicted consumers here in Australia (and also around the world).

Teg and I stay in touch, kind of loosely, and he sent me details of a case he’s investigating, in his new role of lemon-car advocate, concerning a guy named Troy.


Troy owns a SS Commodore, which is like a Pontiac G8, if you’re from America). Troy does something you should never do: fall asleep at the wheel at 70 km/h, which I guess is about 40mph in America. But luckily enough, there is an ‘afterwards’ for Troy in this situation. 

Troy wakes up, and I bet it was a memorable wake-up call, and he’s parked on the side. I bet that wasn't in the script. There’s sundry damage around the car. He’s run through a billion little scrubby trees and a fence.

This would have been a violent, brutal, chaotic event. He’s woken up, he’s looked at the car, there’s a great deal of cosmetic damage. The laminated windscreen is smashed… there’s a whole bunch of things that are suddenly imperfect about his chariot.  

Basically, he looked around and he said: ‘OMG, the airbags, not deployed’. He’s gone into: ‘My car must be defective! I didn’t get my fries with that! I had my crash, I want my airbags!’.

‘Madame, I did not get my happy ending and I’d like to talk to you about that.’

That kind of thing.



I guess, half a dozen times a year, I get complaints to that effect through my own inbox. When I’ve spoken privately to the members of various car companies, they tell me off the record, that their customer care centres have this as one of the most common post-crash complaints. People who did not get their ‘happy ending’. 

So let’s talk about what really happens when your airbags actually go off.


This segment is rated 'P' for Physics, but that’s okay because it’s also rated HE for Happy Ending. So to drill down into that, when you actually deserve your ‘HE' rating ('happy ending'...) in a crash.

You have to stop thinking about car crashes as one continuous event and break them down into three component parts. Every serious car crash is actually three crashes all strung together and it’s the third one that kills you.


Crash No.1:
Car versus world

Crash number one occurs between the car and whatever it hits. This is pretty obvious. You’ve got an unyielding object, the car runs into it and immediately metal starts to bend.

Obviously it takes energy to bend metal so energy is robbed from the car’s kinetic energy to bend the metal and the result is rapid deceleration.

If you’re an engineer or a scientist, you’d probably view the term deceleration as a kind of bullshit physics term and that’s merely because it’s all acceleration. You know, Newton’s second law: F = ma (that kinda stuff). 

Deceleration is just what happens when you’ve got velocity in one direction and acceleration in the opposite direction.

At the moment though, crash number one is just between you and the thing it hits causes this rapid acceleration in this direction slowing you down, and at the moment, but just for a few milliseconds, you and the passengers of your car are completely uninvolved. 


Crash No. 2:
You versus car

Just a few milliseconds after crash number one starts, you become embroiled in crash number two.

Crash number two occurs between you and the car. Hopefully it occurs with the seatbelt. If you’re unrestrained, it’s much worse. You’ll be having crash number two with the laminated glass windscreen - and it never ends well when you try to punch a hole through a laminated glass screen with your head.

So, good safety tip: always wear the belt. As a consequence of the car accelerating rapidly and slowing down, and your body having a whole bunch of inertia, you collide with the seatbelt and your body starts to interact with the vehicle’s restraint systems. 

But that’s okay because crash number two is not going to kill you. It crash number three that chalks you up. We don’t even need the car for that.


Crash No. 3: Internal organs versus skeleton

Most of us are disinclined to think about ourselves as if we are just machines powered to an extent by some gruesome internal plumbing, but when you think about surviving a crash, that’s exactly what you’ve got to consider.

The critical crash number three plays out in exactly this 'internal plumbing' domain.

Your internal organs slosh forward and run into the inside of your skeleton so, in a crash where you hit your head against the glass windshield, your skull will stop moving relative to the windshield but for a few milliseconds, your brain will keep moving, owing to its own inertia. It will run into the inside of your skull. The same thing plays out with the major blood vessels and organs in your chest. The ones that can kill you quickly. 

Your chest will stop moving relative to the seatbelt but your internal organs keep going, thanks to their inertia. All of these things have load limits. Evolution has not endowed us with great robustness in the context of the changes in energy that are experienced in car crashes, the loads that are imposed. If these blood vessels exceed their limits they will fail, and if they do, it’s all over. 



The whole purpose of all of this machinery, these precisely engineered crumple zones, the pyrotechnic seatbelt pre-tensioners, the airbags that are, perhaps, visually the most apparent part of crash protection but really are the last line of defence:

All of these things are aimed at one outcome, and that is to extend the duration of the second collision in order to mitigate crash number three, the one that can kill you.  

So, there’s a whole bunch of engineers, there’s hundreds of thousands of engineering man-hours that jump out of the blocks and try and protect you by mitigating crash number three. This is really what this is all about.

Not all cars are created equal in this domain. Check out the relative differences at ANCAP >>


Obviously all crashes are different. There’s a great deal of variation out there in the real world. So let’s talk about lines of defence.

The primary line of defence for you in a crash is the structure of the car at the pointy end because it’s very carefully designed to deform in a controlled way and absorb energy. This deformation attenuates the amount of load that you experience in crash number two and the knock-on effect is that it mitigates cars number three, which can kill you.

The next thing that might happen in a crash, is determined by a crash sensor. It sometimes says ‘fire off’ the load limiting pre-tensioners in the seatbelt so these explosives devices fire off and they pull the seatbelt tight. This has two principle benefits. 

First one is, it yanks you into the seat so that you present in relation to the airbag in an anatomically correct way that maximises the chance that the airbag can protect you. 

The second thing it does, is it basically eliminates any slack between you and the belt because you don’t want to rush forward and then slam into the belt. You want the belt to be holding you snug and tight. You wouldn’t want to drive with the seatbelt as tight as it would be when those bolts fire off but in a crash, with those high loads being imposed on you, you definitely want the seatbelt that tight. 

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So, a good safety tip is, don’t do this (right). Don’t grab the wheel and then reach down into your bag to fish around for whatever – your lippy, your phone, the bottle that the baby has just dropped – any of that stuff. If you do and you crash and you’re out of position (as pictured) and the pretensioner fires, it could break your collarbone, and that’s going to be bad, the knock-on effects of that in a crash could be very bad as well. It might puncture your lung, it’s certainly going to be painful and there will be weeks to months of recuperation.

You also don’t want to have your hand across the wheel (as pictured) as you reach because if the airbag deploys, it’s going to blow your forearm into your head at 300 km/h, which is the approximate deployment speed, and it’s also going to spoil the life-saving protection offered by the airbag. So don’t do that.

These devices are not risk-free when they deploy. In a serious, life-threatening crash scenario, it's a little bit like having cancer. It’s a bad situation. But we’ve got chemotherapy. Chemotherapy isn’t fun, but it’s better than not having chemotherapy in many cases. Airbags and pretensions are like that. It’s the best we’ve got in the middle of a very grim situation.



This is, of course, why the engineers, who develop this technology, don’t deploy any of this stuff in a trivial fashion. It’s not like: ‘Would you like fries with that?’ at all. It’s like: ‘You’re about to check out, this is the best we’ve got’.

If you don’t get your airbags, your 'happy ending' guess what?

The crash was not severe enough to take you out.

The acid test for this is, in the aftermath of a crash, it’s been loud, it’s been upsetting, it’s been violent and brutal and chaotic and all of those things. But if your brains are intact to the extent that you are able to write the car company a letter, then they just didn’t need to deploy. It really is that simple.

So instead of firing off an indignant missive: ‘Dear Sir, I wish to complain about not getting my happy ending. I crashed recently and your airbags stayed in their box…’ why don’t you write the car company a letter of sincere thanks for saving your life. That’s certainly what I would do.

When carmakers talk about technology to consumers, they talk about bluetooth and a wireless charging pad for the phone and all the other trivial stuff. The toys. But the most impressive technology in cars is stuff that you don’t see. It’s the decision making algorithm that can fire off the airbag in less than a blink of an eye and all of a sudden, this life-saving technology comes out and you go: 'Wow, there’s an afterwards. I might bitch and moan about the airbags.'

In the 1970s, there would not have been an afterwards for you to complain in.  

So, if you’re in crash, you don’t get your airbags, it just hasn’t been severe enough - and that’s really the bottom line.