What triggers an air bag?

[daengmei]

I parked my truck close to the entrance at WalMart. As I shut the door I heard this enormous crash and it was an SUV hitting a yellow barrier pole around the handicap parking, just 15 or so feet from me. Driver backed up a few feet and stopped. I did not see a cell phone... She got out and started crying, saying she need pulled out of the way. At 730am there is little traffic to worry about and I tried my best to calm her. I looked for a strap, forgetting mine is on loan. As I told her I could go inside and get one, I looked and the driver side ball joint was sheared off. Both wheels were facing outwards and I told her to wait for a truck, more damage might happen if I pull it.

I did make sure she wasn't hurt before anything else. Poor gal was crying and didn't know what to do.... laid against me in the rain while crying. I had to insist she got back in to stay dry.

So with that, why didn't her air bag go off? Nearly new SUV. She had hit the pole with the wheel on one side and the fender on the other side.

[Outpost75]

Inertia switch 3g load not triggered.

[osteodoc08]

Wasn’t going fast enough and airbag would have done possibly more damage to driver had it gone off at that slow a speed.

How old was the lady? Should she even be on the road?

Sounds like quite the Walmart trip. I’m not a fan. Walmart seems to draw a certain crowd at times.

Good on you for helping the lady out.

[Winger Ed.]

Some vehicles have what looks like a push button switch behind the bumper in the center.
If the side was hit, the bumper's center may not have been pushed back enough to press it.

Some people unplug them.

I've seen when low end body shops patch a blown airbag case back together, and more or less use glue like bondo
rather than spend a few hundred dollars to get a new one.

[tomme boy]

Used to drive a tow truck right out of HS. Seen lots of airbags not deploy on severe crashes. The company I worked for had picked up a Hyundai in a full frontal crash. One of them died. NONE of the 9 air bags went off. They had that car in storage for almost 2 years as the people sued Hyundai. And they won. Hyundai was at their shop hundreds of times hooking up to the computer and checking over the sensors. Each time the other side had people there to keep watch to make sure something was not changed or tampered with. I know Mark got over $12K in storage fees when it settled.

[daengmei]

Very young pretty gal. When her father?/older man arrived he said "You can leave now." No thanks. I said, "She is very upset and be easy with her." Then I almost left, forgetting I had to shop. When I came out they were still there, now with her husband a soldier. I think I have seen her before and I'll be thanked in the future...one way or another.

[Idaho45guy]

Chevy Colorado air bags go off when doing mild off-roading...

https://www.cnet.com/roadshow/news/chevy-colorado-zr2-off-road-airbags/

Owners of Chevrolet's hardcore Colorado ZR2 off-road pickup truck are having problems with their side curtain airbags deploying in decidedly not hardcore off-road situations, Jalopnik reports, citing reports from multiple owners, and GM doesn't seem to be doing anything about it.

According to owners' statements, their vehicles experienced side curtain airbag deployments while traversing reasonably mild terrain in their Colorado ZR2s. The vehicles apparently determined that the movement of the trucks off-road qualified as rollover events, deploying the airbags and alerting OnStar to what it believed were crashes.

Repair costs stemming from the airbag deployments and the subsequent effects on other vehicle systems have cost owners thousands of dollars, and in many cases, General Motors has laid the blame for the deployment at the owners' feet, according to Jalopnik's report.

The report claims that GM blamed one incident on an owner's modification of a tailgate latch wiring harness and others on the fact that the vehicles were being used off-road, even though the ZR2, in particular, has been marketed as a competent, capable off-road vehicle.

Many of the affected owners believe that the Colorado's airbag sensors are improperly calibrated for a vehicle that is designed for the trail, with some citing the lack of a system like Toyota's RSCA Off switch, which allows drivers to disable the side curtain airbag sensors during off-road driving, preventing unintended deployments.

Nissan owners were having similar problems for years until the company issued a recall and refunds for repairs stemming from off-road related airbag deployment repairs. The company's fix involved recalibrating the side airbag sensors to allow for more height difference from one side of the vehicle to the other before deploying.

General Motors currently offers no such remedy, and many owners are taking the matter into their own hands, whether pulling the fuse that controls the airbag system or installing a switch that allows them to disable the airbags themselves when they want to go off-road. Neither situation seems ideal, since both fixes likely affect the whole airbag system and could leave the driver unprotected in the event of an actual off-road rollover situation.

It's worth mentioning that our own Emme Hall has has extensive off-road experience in the Colorado ZR2, including campaigning one in the Rebelle Rally last year, and hasn't experienced any issues with the vehicle's airbags.

GM representatives didn't immediately respond to requests for comment.

[tomme boy]

If you take any vehicle off the PAVED road the manufacturers can void your warranty. So I can see GM denying the bags that go off when 4 wheeling.

We had a F150 that had less than 1000 miles on it when the motor grenaded. It had a severe rod knock. And the dealer told us to drive it to them and that I was mistaken for the noise. Well it did not make it to them before the rod went through the side of the block.

We fought for a year to get it covered under warranty. They said we took it off road so it was not covered. We lived on a gravel road at the time! We had to drive about a mile from the paved road down the gravel. Once we got the lawyers involved it was taken care of. As a ONE TIME DEAL! According to Ford.

[NyFirefighter357]

During a crash, the vehicle's crash sensors provide crucial information to the airbag electronic controller unit (ECU), including collision type, angle and severity of impact. Using this information, the airbag electronic controller unit's crash algorithm determines if the crash event meets the criteria for deployment and triggers various firing circuits to deploy one or more airbag modules within the vehicle. Working as a supplemental restraint system to the vehicle's seat-belt systems, airbag module deployments are triggered.

United States regulations require deployment in crashes at least equivalent in deceleration to a 14 mph barrier collision, or similarly, striking a parked car of similar size across the full front of each vehicle at about twice the speed. Because airbag sensors measure deceleration, vehicle speed is not a good indicator of whether an airbag should have deployed. Airbags can deploy due to the vehicle's undercarriage striking a low object protruding above the roadway due to the resulting deceleration.

The airbag sensor is a MEMS accelerometer, which is a small integrated circuit with integrated micro mechanical elements. The microscopic mechanical element moves in response to rapid deceleration, and this motion causes a change in capacitance, which is detected by the electronics on the chip that then sends a signal to fire the airbag.

Today, airbag triggering algorithms are becoming much more complex. They try to reduce unnecessary deployments and to adapt the deployment speed to the crash conditions. The algorithms are considered valuable intellectual property. Experimental algorithms may take into account such factors as the weight of the occupant, the seat location, seatbelt use, and even attempt to determine if a baby seat is present.








https://en.wikipedia.org/wiki/Airbag

[merlin101]

Far cry from the first gen air bag systems I worked on! Back then it was drivers side only in many cars and passenger side on a few. Her in NY it's illegal for a salvage yard to sell bags from a salvaged vehicle even if it's there due to mechanical, so they are sold out of state or destroyed. 12 volts sets them off just fine and it can be fun getting creative launching stuff in the air or using them as command detonated land mines!

[Winger Ed.]

it can be fun getting creative launching stuff in the air or using them as command detonated land mines!

There's a guy on youtube who puts them on a bicycle seat, and leaves it in a obvious place.
He then videos it when people steal the bike, and ride off a few yards before he triggers the airbag.

[osteodoc08]

There's a guy on youtube who puts them on a bicycle seat, and leaves it in a obvious place.
He then videos it when people steal the bike, and ride off a few yards before he triggers the airbag.

I thought he used an electric jolt on them. Either way, sounds funny.....but a legal liability

[OldBearHair]

I have three experiences. One, we spun out in a Buick water 1/2 inch deep, one worn tread on rear, slammed into a guard rail backwards and no deployment of anything. Two, following a wrecker with the sharp edge on the back stopped at the light . Started forward on green light, a siren went off very loud. I looked to the left and back quickly and saw the stoplight on the truck. Impact at 10 mph or less. Then a two second pause and boom, the airbag went off hitting me , my arms straight on the wheel. No harm to me except the nasty smell of exlosives. Three, going through the green light, a green car hit the left front coming toward me at about a 60 degree angle. Came to momentarily and saw a steel fence in front, my chin on the dash , head against the cracked windshield, and heard the wrecker driver say "Hey this old boy is still alive, they are usually dead when it is this bad. Next I remember the cutting noises to get me out. Came to on the ER table. One broken leg bone, feet over-extended backwards all ligaments damaged, one split knee cap, one piece of plastic door light cover sliver in left leg that did not show on X-Ray, lacerations on the face,three broken corners of neck bones they didn't find. They told me "Well you are blessed, and you will be sore tomorrow and released me. Later the Dr gave me a leg boot, and the Chiropractor found the neck bones a couple weeks later. The airbag saved my bacon. God Bless America Took a while to get over that. Never did get back the Testoerone level as before.

[scattershot]

Donald Trump triggers Nancy Pelosi, does that count?

[shaune509]

Seat belt retractors also get locked on deployment. a frontal impact with 2 occupants will require the replacement of 2 blown the seat belts, 2+ airbags [ steering wheel and dash assy], the sensors and the reflash of the body ecm at $20000+ before any body work, ie totaled.
Shaune509

[MT Gianni]

I hit 10 deer in a ten year period with no air bag deployments.

[phonejack]

deleted

[Cheeto303]

I dunno, generally I stay away from politics or religion but nowadays they pretty much get triggered by anything.