Timeline of a Car Crash

In designing the Falcon XT, Ford engineers set out to discover the anatomy of a car crash and found that the accident is typically over before we’re even consciously aware of it happening.

This is a reconstruction of a crash involving a stationary Ford Falcon XT sedan being struck in the driver’s door by another vehicle travelling at 50 km/h [30 mph].

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.

6.5 ms – Door pressure sensor registers peak pressures.

7 ms – Crash computer confirms a serious crash and calculates its actions.

8 ms – Computer sends a “fire” signal to side airbag. Meanwhile, B-pillar begins to crumple inwards and energy begins to transfer into cross-car load path beneath the occupant.

8.5 ms – Side airbag system fires.

15 ms – Roof begins to absorb part of the impact. Airbag bursts through seat foam and begins to fill.

17 ms – Cross-car load path and structure under rear seat reach maximum load.
Airbag covers occupant’s chest and begins to push the shoulder away from impact zone.

20 ms – Door and B-pillar begin to push on front seat. Airbag begins to push occupant’s chest away from the impact.

27 ms – Impact velocity has halved from 50 km/h to 23.5 km/h. A “pusher block” in the seat moves occupant’s pelvis away from impact zone. Airbag starts controlled deflation.

30 ms – The Falcon has absorbed all crash energy. Airbag remains in place. For a brief moment, occupant experiences maximum force equal to 12 times the force of gravity.

45 ms – Occupant and airbag move together with deforming side structure.

50 ms – Crash computer unlocks car’s doors. Passenger safety cell begins to rebound, pushing doors away from occupant.

70 ms – Airbag continues to deflate. Occupant moves back towards middle of car.
Engineers classify crash as “complete”.

150-300 ms – Occupant becomes aware of collision.

Mind Hacks corroborates these conclusions, stating that the start of concious awareness is typically found to be around 200-300 ms.

55 thoughts on “Timeline of a Car Crash”

  1. Lloyd Morgan Post author

    @Bob Sagazoid

    I completely agree with your following statement:

    As long as people have the mentality that they will avert serious injury or death by simply wearing seat belts people will continue to disregard and ignore their responsibilities as drivers.

    Using this as an excuse to not wear a seatbelt yourself (or to advocate the wearing of seatbelts by others) is, however, a complete logical fallacy.

    To wit:

    The idea that seatbelts cause accidents is so ridiculous it could only have come from an economist. That economist is Sam Peltzman, who in 1975 published a paper demonstrating that drivers did indeed drive more dangerously after mandatory seatbelt laws were passed in the US. He argued that despite technological evidence showing that seatbelts save lives in a given accident, there was no evidence that the seatbelt laws had reduced driver fatalities. In other words, drivers take advantage of seatbelts to drive more dangerously rather than to live longer. More compellingly, Peltzman detected a rise in pedestrian and cyclist fatalities when seatbelt laws were passed.

    This is a classic case of moral hazard in action. To describe why, consider the two ways in which you can get into an accident:

    1. You are at fault (you crash into someone or something).
    2. Another driver is at fault (someone crashes into you).

    In case one, where the crash is your own fault, a seatbelt brings no advantage: by wearing a seatbelt you’re probably driving more dangerously than you would without one and the net result is the same. The advantages a seatbelt confers are negated by the more dangerous driving.

    In case two, however, a seatbelt offers you much more protection against the outcome of the crash. By not wearing a seatbelt in this scenario you are putting your life at risk. Regardless of your opinions of whether others should take more notice while driving, by not wearing a seatbelt yourself, you’re not lessening your risk of death and/or serious injury by doing so.

    If you drive safer by not wearing a seatbelt (as you suggest), then why not drive safer while wearing a seatbelt? Not only are you protecting others by being a safer driver, you are protecting yourself against those stupid drivers who wear seatbelts.

  2. Treadmill Traci

    So how many milliseconds does it take for a distracted teen to look down at their phone and read a text? How many milliseconds to look in the rear view mirror to check your hair? How many milliseconds to look down and tune the radio? This article definitely helps put things in perspective, thanks for the info!

  5. Vedette

    I am really speech­less. the break­down you pre­sented is really scary and will cer­tainly have it in mind when i am dri­ving.. thanks for shar­ing it.

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