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Cervical injury during rear end collision

Cervical injury during rear end collision

Cervical injury during rear end collision

(OP)
Hello,

I'm trying to figure out if two scenarios have different physiological outcomes on the neck during a collision.

First scenario: Driver in car at rest, directly rear ended by a large object moving at a high velocity.

Second scenario: Driver in car moving backwards at a high velocity, runs into a large object that is not moving.

Assuming things like head positioning and awareness are the same in both cases, would there be any reason to see a different outcome from the neck's point of view?  My intuition tells me there is no difference when certain assumptions are met, but maybe I'm missing something.  Thanks for your help!

RE: Cervical injury during rear end collision

US barrier crash tests seem to be based on practical equivalence, i.e., moving barrier strikes stationary test article.  I have no knowledge that strict equivalence has been proven or not.

I would expect some differences, but they may not be important in something as violent and irreproducible as a car crash.
 

Mike Halloran
Pembroke Pines, FL, USA

RE: Cervical injury during rear end collision

Most of the video I've ever seen from the IIS crash testing is a moving vehicle against stationary obstacle.  Just given the difference in momentum and kinetic energy, I don't see how a moving obstacle could duplicate the impact energy and momentum of a moving vehicle impact.

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RE: Cervical injury during rear end collision

If the body experiences the same accelerations in the 6DOFs then they should be identical from the body's perspective.  A car or wall moving at exactly the same speeds my cause slight differences in accelerations due to effects such as rotational inertia of the wheels.

Rob Stupplebeen
https://sites.google.com/site/robertkstupplebeen/

RE: Cervical injury during rear end collision

Go with your gut, "certain assumptions" not withstanding, how can the localized neck of interest possibly see any difference between the different impacts?  Draw up the FBD and puzzle it out, objective velocity shouldn't have any bearing on an impact, just the relative accelerations involved.

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