I've suffered a few high speed crashes, the most recent summer 2020. I completely destroyed the helmet I was wearing, rebook my right humerus (only a crack), and bruised several ribs due to my shoulder being the second point of impact, my head being the primary. No concussion. That was probably the worst solo crash I’ve endured. I’ve also bounced my face off a car door, and hit a tree with my head, no concussions in those instances either. In each instance, I received emergency medical care, and I am confident saying the lack of concussions is due to a properly worn, and high quality helmet.