Cervical injury during rear end collision

[Rancho12]

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.

https://100001.onl/

https://1921681254.mx/

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!

 

[IceBreakerSours]

You are assuming the situation is entirely symmetrical from the perspective at the neck within a brief time window (a few or a few tens of milliseconds, perhaps?) - which may or may not be a fair approximation, depending on the question you are asking of the model. I think the time window is important - In the second case, the car will come to a complete stop (more likely get crushed from the rear) whereas in the first case, the car will end up turning into a projectile.

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[moon161]

Case one is sudden acceleration followed by unknown deceleration.
Case two is sudden deceleration.

 

[moon161]

Also, neither the body or supports are symmetric from front to back. You've got seatbelts that restrain you if you drive into a wall, you've got seatbacks of varying quality if you back into something. The shearing effect on the spine is gonna be very different if the whole body, head included is supported from behind or if the head is stopped short by the neck as the seatbelt locks and catches the thorax.