Airbag Deployment Questions

Okay, does anyone know exactly how the current airbags in the Tacoma double-cab deploy? For example, in a frontal collision (causing front airbags to deploy), do the side airbags deploy as well or only during side impacts? Same question regarding the front airbags during a side impact. What about an angle impact in one of the four corners of the vehicle?

Evidently some vehicles offer an option of tailoring airbag deployment, enabling or disabling certain ones. Is this strictly (or even) a dealer controlled option or am I missing something in the owners manual that I can do? Of course, I'm aware of the passenger seat airbag control.

 

No one will be able to give you a definitive answer on this. It all depends on angles speeds etc... A lot goes into the computation of when to deploy the air bags. Nothing to worry about IMO.

 

Some great videos by whippet answer your questions right there. Never heard of trail prong deployment myself but never looked into it either. The reason only the sides airbags go off or only the front airbags is because of where the impact sensors are located. But this doesn't always mean they're going to deploy either. Cause like jimmyh said, there's a lot of variable that go into it. For example in my case I rear ended a guy at approximately 30 km/hr and the airbags never went off. Upon disassembly you could see clearly that the left front impact sensor for the airbags was hit. You just never really know what will happen. And now I have to ask, how come you're interest in how the airbags on the Tacoma deploy?

 

Good videos, and as far as controling the air bags, I know on my off road, you can turn off the side curtain, for off road situations, so they don't go off if your on a steep tilt. Other than that, I know of no other settings. Just have to have faith in what Toyota designed.

 

in the 09-12 Tacoma , once you engage 4x4 , side curtain airbags are automatically disabled. Also , the side airbags should only deploy in a side collision when the side sensors detect impact. there is no option anywhere to manually disable any airbag besides the front passenger one. no dealer, or shop is allowed to bypass or modify any airbag system per the Nhtsa.

 

Are you sure about that? Why would switching to 4x4 turn those off? Could still have a side impact while in 4WD.

 

I was looking at the schematic diagram for the srs as I typed the original post.
there is clearly a 4wd connection to side curtain airbag cutoff sw.

 

Maybe what you see is the side curtain air bags shut off button can only be pushed while in 4WD.

 

Correct, I see it now in the schematics, 7.5a> RSCA off >airbag ecu> curtain airbag cutoff SW

 

I know some manufacturers deploy the side curtains in frontal impacts to keep your head from hitting the B-Pillar as you rebound, keep your head in the passenger compartment, or from hitting any hard surfaces.

http://www.youtube.com/watch?v=hThEj28hsds

From the IIHS: " After the dummy moved forward into the frontal airbag, it rebounded into the seat with its head grazing the side curtain airbag and protected from any stiff structure that could cause injury."

And you can see where the dummy grazed the curtain airbags here:



Sadly for Toyota, the Side Airbags don't deploy in the front crash tests I've seen from the IIHS and NHTSA, but that doesn't necessarily mean they won't. They can, they just didn't in the IIHS and NHTSA tests. The thing I find interesting about the NHTSA tests is that the Front Air Bags deploy in those side tests, but not in the IIHS ones.

Here are the NHTSA Tests:

Frontal: http://www.youtube.com/watch?v=B5kye8Wm6yY

Side:http://www.youtube.com/watch?v=IfO-ucb8Azo

 

I knida figured they would never truly be "off"

 

Well, after searching diligently through the manual and internet, never thought about looking at crash tests to find the answer. Evidently the alternative airbags (side during frontal, etc) don't typically deploy. Thanks, Christian.

Mainly just curiosity. Manufacturers often tout which airbags they have (front, side, etc), but rarely provide a lot of details about how they work or interact. The NHTSA requirements provide some details (must protect an unbelted, average weight, adult male, for example), but gets a little weak (and confusing) after that.

Found out myself about permanently disabling the airbags. Appears the age of tailoring airbag deployment is over. Now, except for the front passenger seat, an NHTSA waiver is required, which is difficult to get without specific disabilities. Even with that waiver, dealers or manufacturers can still refuse.

Of course, the side airbags can be temporarily disabled while off-roading (RSCA button). For a more permanent solution with vehicles used only off-road (racing, etc), there's always the options of removal or triggering intentionally beforehand.

 

Usually depending which area of the vehicle gets hit determines what air bags go off. If you get hit hard enough in the front all air bags should go off. There are sensors in the front under the headlights and side impact sensors underneath the scuff plates. The airbag ECU also has a sensor that determines yaw and other vehicle angles so it knows what air bags to deploy. I had a 2009 tundra and got nailed in the driver front wheel. All air bags went off in that case cause he hit me so hard. Truck was totaled before I could even get the first oil change.

 

I had been wondering about the sensor placements, So replacing/upgrading the front bumper wont kill my airbags?

 

Sensors aren't mounted to the bumper. They are mounted behind it. If you look down from the front of the truck with the hood open you will see them.

 

Ahh, OK, cool!
Now I can start Christmas shopping for myself again!
I seen a few bumpers on here that would like very sweet on my Taco..

 

I stole this
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There is a general misconception that airbags provide a soft cushion and will prevent bruising or other minor injuries in low severity crashes - this is incorrect. SRS airbags are designed to reduce peak loads on the head and chest in severe crashes (those where death or long term brain injury are possible). When deploying, the airbag is firm, but it absorbs energy as the gases are released through the vents.

While airbags significantly reduce the risk of serious or fatal injury in crashes, there are some risks from the deployment of airbags in low speed crashes. For this reason modern cars use a range of intelligent sensing functions to ensure that a crash is really happening (not just a bump in the road or a minor knock in the car park) and to fire airbags at the best time. This reduces the likelihood of airbags deploying in minor crashes.

Modern design and construction methods used in today’s vehicles include progressive crumple zones in the body and frame structure to reduce the rate of deceleration in severe frontal impacts. For this reason, damage sustained by a vehicle in a head on collision may appear quite extensive and the airbags may not have deployed because the crumple zones have absorbed a significant amount of the energy of the impact. In these cases, the airbag sensors have detected that the rate of vehicle deceleration has not been sufficient to require triggering of the airbags.

Typically, the driver and or passenger airbags deploy in head-on collisions where the force of the impact is equal to or greater than striking an immovable and non deformable barrier (such as steel or concrete) at a speed of around 18-25 km/h or higher. In offset collisions or in a head-on collision with another vehicle or other deformable and/or movable object, the speed would generally need to be significantly higher than 25 km/h for the airbags to deploy. Airbags designed for frontal impacts usually do not deploy in rear end collisions, side impacts, rollover accidents or in most underride accidents.

In addition to the frontal impacts described above, airbags may deploy in cases where:

A moderate to severe impact has been sustained by a vehicle’s undercarriage such as when striking an elevated median strip or kerb.
A wheel has struck a deep (severe) hole or pothole, or when driving down a very steep slope and the front strikes the ground at the end of the slope.
Damage to vehicle body panels may appear relatively minor in these cases.

 

You can turn them all off. In front of the shifter under the radio is the SRS ECU. Follow the bright yellow wires. Disco the battery and unplug the SRS ECU and your airbags will be permanently off. Obviously, use your own judgement. I have a full cage and five point harness, and disabled mine in case I dirt dart on a jump. You can use the old airbags for some interesting things if you are of the mind to do so. Safety third!

 

Massive thread necro -- almost a decade!

Does airbag deployment -- any or all of them -- disable the engine? Can you immediately turn the ignition key, start the engine, & drive away post-deployment? (Assuming of course that the vehicle & driver is otherwise operable, no severe damage to drivetrain or electronics, etc.)