[manyu]

Dear all ,

I have been a member of this esteemed community since 18 years and visit the forums regularly.

I would like to share this unexpected incident where i was being driven by my driver in my 2019 X3 G01 near Sikanderpur metro station Gurugram when a RMC truck passed us from the left and had a tyre burst.

The truck must have crossed us 3 or 4 feet apart when the his tyre burst and all curtain airbags in my car got deployed along with the passenger side seat air bags. This happened without our car got a single scratch or dent/impact.

My left hand got severely injured by the incident (pics attached) and have dropped the car today itself for repairs pending insurance approvals. This entire incident has me lost faith in BMW as a brand.

Dear members kindly help and chip in your views on how to go about this incident.

[agambhandari]

Sad to see your hand injured, hope you and your family are safe and recovering now.

From your description, i can decipher that the tyre burst must have let out air with a reasonable force to trigger the impact sensors on the side of the car (that's why passenger side and curtain airbags are deployed and not the remaining).

There was obviously no way for you to avoid this, but would suggest you to follow up with BMW so they scan and see the crash data and confirm what triggered this deployment. I would not lose faith in such a case, this was clearly an unexpected scenario that most likely triggered the airbags.

[NomadSK]

Originally Posted by manyu

The truck must have crossed us 3 or 4 feet apart when the his tyre burst and all curtain airbags in my car got deployed along with the passenger side seat air bags.

Glad that you are safe.

Side impact sensors are pressure based unlike the front sensors which activates on rapid deceleration or on G forces.

But I’m surprised a loud tyre burst can activate the airbags, was it that loud enough to mimic an explosion and create some blast wave, highly unlikely.

But IMO this should be taken care under manufacturing defect, probably will need to recalibrate their sensors and in any other developed country you can actually drag the maker to courts.

[Chetan_Rao]

Originally Posted by NomadSK

...

But I’m surprised a loud tyre burst can activate the airbags, was it that loud enough to mimic an explosion and create some blast wave, highly unlikely...

It's not the sound itself, it's the pressure and resulting shockwave.

A commercial vehicle tire would be ~100 PSI inflated pressure (without even accounting for the added pressure from the vehicle's weight and possibly loaded bed), and one exploding 3-4 feet away could very easily create a momentary shockwave enough to trigger pressure sensors.

BMW would need to run diagnostics to confirm what exactly caused the airbag trigger event, but a 100 PSI inflated & loaded tire exploding a few feet away is very capable of causing serious damage.

Sample video, seems pretty similar to the scenario OP described:

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

[NomadSK]

Originally Posted by Chetan_Rao

A commercial vehicle tire would be ~100 PSI inflated pressure (without even accounting for the added pressure from the vehicle's weight and possibly loaded bed), and one exploding 3-4 feet away could very easily create a momentary shockwave enough to trigger pressure sensors.

This makes sense, if it creates a blast wave over the threshold of the pressure sensors to activate the airbags.

However, this threshold scenario should have been taken into consideration by the manufacturer during the design stage to avoid such specific circumstances. But then I guess, it will compromise in deploying of the airbags when needed while getting T-boned or having side impacts.

[ajmat]

Originally Posted by NomadSK

But I’m surprised a loud tyre burst can activate the airbags, was it that loud enough to mimic an explosion and create some blast wave, highly unlikely.

Originally Posted by Chetan_Rao

It's not the sound itself, it's the pressure and resulting shockwave.
]

Unfortunately, this is the case, once, when driving through Marathahalli, I heard a loud bang and shock waves and made an emergency stop. I then saw an auto driver behind me in shock and dazed. There had been no contact or damage.

It took 2 min to process that a Volvo bus passing opposite had burst its tyre, and we were in the path of the shockwave.

Unfortunately, Manu was right next to the truck so am not surprised by this. Its not the BMW's fault, the duty of the airbag is to anticipate and protect. Please document this with pictures etc so that BMW can fine tune things and also that you have a record. When you sell the car on, the airbag trigger record might remain on the ECU.

Its just plain bad luck

[Brumby]

Originally Posted by manyu

The truck must have crossed us 3 or 4 feet apart when the his tyre burst and all curtain airbags in my car got deployed along with the passenger side seat air bags. This happened without our car got a single scratch or dent/impact.

My left hand got severely injured by the incident (pics attached) and have dropped the car today itself for repairs pending insurance approvals. This entire incident has me lost faith in BMW as a brand.

As you mentioned that there is no physical damage to the car, that surely means that the either the sensors were set to higher sensitivity than required or there was a malfunction triggered by the shockwave.

An investigation must be carried out by BMW.

Originally Posted by Chetan_Rao

It's not the sound itself, it's the pressure and resulting shockwave.

Sample video, seems pretty similar to the scenario OP described:

The sample video shows physical damage to the car, hence deployment of airbags is as expected.

Originally Posted by ajmat

Unfortunately, this is the case, once, when driving through Marathahalli, I heard a loud bang and shock waves and made an emergency stop. I then saw an auto driver behind my in hock and dazed. There had been no contact or damage.

It took 20 min to process that a Volvo bus passing opposite had burst its tyre, and we were in the path of the shockwave.

Unfortunately, Manu was right next to the truck so am not surprised by this. Its not the BMW's fault, the duty of the airbag is to anticipate and protect. Please document this with pictures etc so that BMW can fine tune things and also that you have a record. When you sell the car on, the airbag trigger record might remain on the ECU.

As far as I know, no airbag should deploy unless:
1. There is an impact causing physical damage to the vehicle
2. Though can be created only in a lab/testing facility, a case where decelerating force is high enough to make the sensors believe that there is an impact.

So this is a clear case of over sensitive airbag sensors or a malfunction, due to aging or wear and tear of the circuit.

Hope BMW does a proper investigation and a corrective action is taken.

Cheers.

[Mystic]

Airbags deployment happens if certain conditions are being met. These conditions can be infinite and impossible for the OEM to be sure that every possible scenario is considered. In your case, tyre burst to big vehicles on multi lane highway in close proximity is very common and I think this scenario must have been already considered. The root cause may be something that is beyond us (In India we tend to put metal statues of Gods on dashboard over the airbag and imagine if this scenario is considered on what would happen to passenger in time of deployment of airbag to the sharp edged statue). Another scenario is after market wirings in which technicians freely conceal the wire behind the curtain airbags). Let the specialists figure it out instead of us speculating. This case must be brought to their attention. May be there is a work around to figure out from the computer like black box in planes to understand the airbag deployment especially when it is in a luxury car). This reminds of how much we are depending on computers these days. It seems a self driving car decided to crash head on with another car to avoid a pedestrian. The computer took a logical decision.

[after]

Originally Posted by NomadSK

But I’m surprised a loud tyre burst can activate the airbags, was it that loud enough to mimic an explosion and create some blast wave, highly unlikely.

Tires of heavy vehicles have a lot of air in them. Many manufacturers recommend 100+ PSI cold pressure, this tire was hot plus Indian trucks are grossly overloaded most times. A tire like that bursting can kill a human standing nearby, or cause severe injury and deafness, there are plenty of documented cases online about this. So I can absolutely see how the airbags triggered. It's bad luck for you, though.

[Random_Alien]

As others pointed out, the tyre burst pressure wave may have triggered the airbag sensors. However, we must also take into account the 3-4m gap. Pressure decreases sharply as distance increases. So, vaguely estimating using say a 120psi tyre, the sensor could have detected anywhere from 5N to 80N force.

80N is a significant amount of force. Not too much, but not negligible either. I suggest asking BMW to investigate on this matter.

Hope you're feeling better now. Stay safe.

[Reality]

That is a bad one. Take care! New fear unlocked as I have been in a similar situation where a truck tyre burst while i was overtaking. It took me a couple of seconds to figure what happened. There was no impact on the car thankfully but the sound and vibrations were loud and scary. Dash cam footage attached.

[Jeroen]

Yes, most side impact airbag sensors are of the pressure kind. But they are built inside the chassis frame. When a side impact occurs, the frame, or bits get compressed and that triggers the sensor.

Obviously, the chassis frame is not air tight, but a collision will compress the air inside quick enough to trigger the sensor.

An outside occurance such as this one is very unlikely to affect he air pressure inside the chassis frame. The pressure wave would need to make its way through some very narrow openings in the chassis to the sensor. I don't see that happening.

Unless it somehow managed to push a panel inwards. If the tire exploded near enough maybe a panel was bent, momentarily, inwards which would raise the air pressure and trigger the sensor.

Look for some tell tales on the car, anything that looks slightly deformed?

Jeroen

[speedmiester]

Truck tyre bursts can be scary and destructive if you are in the vicinity.

I had faced a similar incident few years ago in my Ecosport. This was on the NICE road and the truck ahead had a tyre blowout just as I was about to over take it.
The sound was very loud and the debris hit the front of my car, but luckily there was no damage.

This got captured in the Dashcam. Though, there is no audio in the video, just the dust and debris from the blowout can be unnerving.

https://www.youtube.com/watch?v=91cSU4y0ULk

Recommend to document the incident for insurance purpose and any potential issues down the line. See if you can gather any CCTV footage which might have captured the incident, this will help in your insurance claims.

[whitewing]

As others have mentioned, the shock wave is quite intense. Have seen a few instance where we could feel the shock wave across quite some distance.

While unfortunate, thank your lucky stars that your ears are unharmed and the tyre burst did not pick up additional debris on to your car. Leaving the paint & the glasses intact.

[bravo82in]

The force generated by a tyre burst and the resulting shock wave can be extremely powerful. As an orthopaedic surgeon, I have encountered cases where such incidents led to fractures and blast-induced lung injuries—some severe enough to be fatal. Fortunately, in your case, the BMW’s sensors were sensitive enough to detect the intense pressure changes, triggering airbag deployment. From what I observe, the airbags functioned exactly as intended, and I see no fault with their performance