My 2nd guess as to why is that if helmets were effective when it matters, at higher speeds It matters at low speeds. Falling over the handlebars of a near-

My 2nd guess as to why is that if helmets were effective when it matters, at higher speeds It matters at low speeds. Falling over the handlebars of a near-stationary bike and on to your head is a serious injury. I've done it with a helmet on and taking some of the blow in my arms, and still had to lie down for an hour afterwards.