Air bags: why didn't they inflate when Tiger Woods hit the tree?

The pictures of Tiger Woods vehicle after it hit the tree look to me like the air bags should have inflated but reports say not.

What are your conjectures?

He was traveling less than 35 mph at the time of impact.

How old of a car would it have to be for a sub-35mph impact airbag deployment?

If he were a politician, I would say professional courtesy.

Otherwise I got nothing except to say that my son hit a tree at about 25 - 30MPH, in a 15 year old van, and the airbag deployed.

I have a '98 Corolla and my airbags didn’t inflate when I was struck from behind a few years ago.

Thread win.

Probably early to mid 1990s. Airbags didn’t really become common until the late 80s and initially they were hailed as the next big thing in automotive safety. As injuries from minor accidents started becoming more and more common, they started adding regulations for when exactly the things should deploy so that they weren’t likely to cause more harm than good.

A friend of mine was involved in a minor fender bender in a parking lot in the early 90s. If he hadn’t had an airbag, he would have been fine. The airbag deployed, though, and he ended up with severe burns on his wrist and bruising from the airbag. As I recall, it was around this time that airbags started to get a lot of criticism for hurting people in minor accidents. A few kids also got seriously hurt or killed by passenger side airbags, which led to even further regulations. Not only is the speed (or actually, the deceleration force) regulated, but the type of airbag is also regulated as the earlier types were more likely to cause injury.

I hit a huge buck a few weeks back, and the airbag didn’t go off. The car was in really bad shape, windshield wrecked, fender mutilated.

The Highway patrol officer said that airbags go off only on direct hit, high impact collisions.

I was a bit shocked that mine didn’t go off, but oh well.

I was told once about 10 years ago that joyriders in NJ had a new trick; they would steal a car, then when they got tired of the fun, if they found a parked police cruiser - ram it from behind to set off the cruiser’s airbags. (Then take off while the unprepared occupants were still recovering, I presume).

Does a car have to be moving to deploy the airbags? Is the trigger hooked to the car computer and reading speed? Or is it something like a spring-loaded device that if the impact is sudden and sharp enough, will fire the airbag?

The pictures of Tiger’s car look like things crumpled in progression, tearing a big chunk off, rather than one sudden brick-wall stop.

The device that deploys an airbag is called a MEMS Accelerometer. This article explains how it works. I don’t believe the car would have to be moving for the airbag to be deployed, I am not 100% sure but I believe the MEMS Accelerometer is completely independent of the speedometer.

I wouldn’t bother with that article; the author doesn’t appear to know the difference between an accelerometer and a tachometer.

Your car has a computer called the “airbag control unit.” This unit receives data from sensors in various locations, and assesses the movement of the car based on a complex algorithm taking into account all of these data. From Wikipedia: