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What is Closing Speed?

Posted: Fri Jun 22, 2012 1:45 pm
by brian
Q: What is closing speed?

A: Closing speed is used to indicate the speed of approach of two colliding bodies immediately before contact.
  • It may further be defined as the algebraic sum of the velocity components of two vehicles along a reference line connecting their centers of gravity, and it is generally expressed in miles per hour.
    For a simple example, the closing speed in a central rear-end collision is the difference between the forward velocities of the two involved vehicles.
    Closing speed, by itself, does not provide a complete measure of impact severity, since it does not include an indication of the mass ratio of the two colliding bodies.
    For example, with a given closing speed, a heavy truck or a freight train will obviously produce a more severe impact for its collision partner than would a subcompact automobile.