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Rear ended Airbags not deployed in car that caused accident

We drive a 2008 Equinox and were rear end by a 2002 PT cruiser, damage to our car is considerable (bumper, lift gate, spoiler, muffler, and possible frame damage). the PT cruiser was worse, The wife was amazed that the PT’s airbags didn’t deploy, she feels that if a cars front end is damaged the airbags should deploy. The only thing I can think of is that his bumper never actually hit our car but went under ours.

Air bag systems have multiple impact sensors and a computer that determines if and when to deploy the bags. What may look like a severe crash to you, may not to the system.

Or it’s one of those people who drive for months or years with that constant little yellow glow .
“aah, doesn’t mean much, I’ll fix that when I have boat loads of spare money.”

Was the driver of the other car injured? If not, then the airbags probably did their job in not deploying… They generally are designed to not deploy unless the impact speed is over 10 mph, and even then it is dependent upon the exact distribution of forces in the accident.

The damage you describe to your vehicle could easily occur in an impact of 10 mph - even a 5 mph bumper strike can easily run $1000-3000 in damage on many cars… which is probably about what your Equinox suffered… and describing the PT Cruiser as “worse” doesn’t really help us narrow down how much damage it really suffered - it might be very much inline with the amount of damage expected in a 10 mph impact…

That car could have been in an earlier accident where the air-bags went off and they never fixed them when the put it back together (although they were suppose to).

In a ‘submarine’ accident like yours the impact is less, lots of damage as your car scrapes across the PT, but not a sharp impact. That’s my guess as to why the PT’s airbags didn’t go off. As long as they weren’t hurt, it’s a good thing.

Did’t clarify the accident. Pt Cruiser hit us at approx. 35-40 mph. Driver and passenger were not hurt to my knowledge. damage to PT was grill, hood, pass. side fender, loss of fluid prob coolant, Car was not drivable

That damage is typical of this type accident, as the PT went under your car creating all the damage absorbed some of the energy. No easy way to tell if the bags should have gone off.

35-40 mph? I doubt that the impact speed was anywhere near that high… even if the driver is traveling 35 mph, any braking before the accident scrubs off significant speed. 35-40 mph impact speed is likely to result in some significant injuries even if the airbags do deploy.

Here’s what a 40 mph collision in a PT Cruiser looks like… note that the front of the car is pushed back almost to the A-pillar.:

Airbags are designed to deploy only if deploying them will help more than harm the occupants of the vehicle. If the occupants of the PT Cruiser were not injured, the air bags were not needed and may have actually injured them by deploying (burns and temporary tinnitis/respiratory irritation are common injuries from airbag deployment).

My sister was in a single vehicle accident a few years ago after the driver fell asleep at the wheel. The car was traveling 70 mph when it veered into the median, went airborne across the oncoming lanes of traffic (15-20 feet according to witnesses), and landed primarily on its nose and front wheels in the ditch on the other side of the highway. The most serious injury is that my sister broke her thumb. When I picked her and the driver up at the ER, she complained that the airbags did not deploy during the accident. I told her that the airbags would have done more harm than good in that type of accident and that is why they did not deploy. Airbags typically become helpful around 25-30 mph if the car is colliding with an immovable object.

A lot of it depends on where the sensors are located. If they are mounted low and the majority of the impact was high then the bags might not blow. There are several variables in this but, just because the vehicle was hit in the front does not mean the bags should have blown.

I"m not surprised the rear end of yours was significantly damaged. There were some studies done a few years ago (sorry, I don’t have actual data), and from what I remember, SUV’s (then fairly new to the mass market) always had incredible bills when hit from behind. Everything from rear mounted spares destroying the gate, window, wiper, even themselves, to bent/broken hinges and damage all the way up to the roof, and even damage to the body structure. That was all from under 30mph crashes.

Pt Cruiser hit us at approx. 35-40 mph.

How fast were you going?

We were stopped. waiting for the truck and trailer to make a left turn. PT never slowed down or applied brakes

All of the reasons for non-deployment have been posted here…

And I’d still wager that the PT Cruiser wasn’t going 35-40 mph at impact. How do you know that was the speed they were going? The posted limit? If so, that isn’t proof of anything. And how do you know they never slowed down or applied brakes?

I have a hard time believing the impact speed was that high and that they escaped injury without airbags deploying…

I’ll use my own car’s wiring plans to illustrate.

As you can see, in my (typical) setup there are multiple sensors, each of which feeds into an “assembly center” (multiple inputs into one system). Each is an inertia sensor. A signal indicating an excessive deceleration rate from any one sensor will trigger the airbags.

As you can also see, the sensors are all at bumper level. If the PT Cruiser’s bumper went under your car’s bumper, the Cruiser’s sheetmetal and the action of the engine being driven below the unibody (they’re designed to do this) may have absorbed the energy at a rate slow enough (the speed with which the Cruiser’s road speed decreased) that the inertial sensors did not trip the bags.

Or, Ken may be correct. He often is.