It is axiomatic that wearing a helmet is the single most effective way of reducing head injuries and fatal accidents on motorcycles and bicycles. One study shows that wearing a helmet has been shown to decrease the risk of serious injury on a motorcycle by 70% and decrease the risk of a fatality by 40%.
Wearing a bike helmet is the lowest possible hanging fruit to save lives on motorcycles and bicycles. We are making tons of progress, we just need that progress to continue.