What Your Car Does in a Crash

By Deane Barker on February 20, 2009

Anatomy of a crash: This is an incredible analysis of a crash involving an Australian Ford Falcon XT.

0 milliseconds – An external object touches the driver’s door.
1 ms – The car’s door pressure sensor detects a pressure wave.
2 ms – An acceleration sensor in the C-pillar behind the rear door also detects a crash event.
2.5 ms – A sensor in the car’s centre detects crash vibrations.
5 ms – Car’s crash computer checks for insignificant crash events, such as a shopping trolley impact or incidental contact. It is still working out the severity of the crash. Door intrusion structure begins to absorb energy.

It’s incredible how much processing the car does in such a short period of time. By 70ms, the air bag is already starting to deflate, and, so far as the car is concerned, the crash is considered “complete.”

Here’s the real kicker:

150-300 ms – Occupant becomes aware of collision.



  1. Living up in Northern MN I got to get to know some of the test drivers for Bosche brake systems. They have a winter driving course up by the airport in Baudette. He was telling us about the anti rolling software they are writing for SUV’s. At that time the limitation was the speed of electricity to get the signals to the brakes fast enough to stop the roll from happening.

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