Recently, I've had more requests than "normal" along the lines of "how fast do I have to be going to get an airbag to deploy," or "what impact speed is required to get an airbag to deploy?" This prompted some light research into what's being said on the internet that I thought Forum members might find interesting.
From "Yahoo! Answers:
Some of the answers there weren't too terribly bad......I believe I was traveling somewhere around 25mph when the accident occurred and my airbags went off. The front of my car is pretty smashed in, and the car is probably totaled, etc. My paranoid Mother claims you have to be going much faster than 25-mph to set off your airbags, but I'm 98% sure that is wrong....
From "how fast do you have to go for airbags to deploy"
and a couple personal favorites from the RX8 Club.vom forum "what does it take to set off a airbag":...Generally speaking over 25MPH. The impact must be frontal and not side. Thats 25mph as if you hit a wall, non moving obsticle. If you hit a car from behind and it moves forward then the impact must be much greater to fire the bags. Also hitting a car head on when both vehicles are moving at say 12MPH will set them off. So any combined frontal force over 25MPH will usually do it.
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...This is only a guess on my part but if you locked the wheels during your skid the car could have been sliding more that 40 MPH but the computer thought is wasn’t moving at all. Speed of impact is the main thing that controls the bags. Wheels not moving hitting the back of a truck going forward = not enough the set off the bags?? Again just thinking out loud ...
And then there are the significantly better technical references like this from ih8mud.com topic "Airbag Deployment with an Aftermarket Bumper". There's actually some good information sprinkled into that Forum thread....Correct me if I'm wrong...air bags deploy when the sensor in the panels and bumpers are activated (hit by the other car)...
There's still a lot of misinformation out there about "when does an airbag deploy" and this might be a good place to collect some of the really odd (and some of the really good) references.