There is nothing gentle on the brain about a bumpy ride. Concussions are not just caused by the brain banging against the skull. A diffuse axonal injury includes parts of the brain than never can touch the skull. The up and down of a bumpy ride can push the brain into the brain stem area. Those connections are very critical.

If you don't believe us, go ahead, knock yourself out. Take a bumpy ride and see how you feel afterward.

btw, The occasional bump in the road is not the issue. It is the repetitive nature of a bumpy road that is.