dj222,

The people who suffer concussions and TBIs in vehicular COLLISIONS smashed their heads into solid objects.

It take a 4.5 G impact to cause whiplash. It takes 60 to 80 Gs to cause a concussion. BTW, Whiplash causes the same symptoms as a concussion except for distrurbed mental functions. Anxiety can cause disturbed mental functions.

I seriously doubt you got a concussion hitting a deer unless if can through your windshield at high speed and hit your head.

No car made can cause more than 1.7 Gs by braking or swerving.