Actually, there is strong debate in the cycling community about the effectiveness of helmets. Two main points come up repeatedly:
1.Helmets give riders inflated confidence and they do things they wouldnt normally do.
2.Helmets decrease bike useage (this is pretty much confirmed globally). Opponents of compulsory helmets laws cite this as one reason for reduce accidents/head injuries. Simply, less people ride when helmets are mandatory.
I’m not taking a position here. I dont use one here, simply cos i hate wearing them. When i did bike messenger work in college i had to wear one (take it off, instant dismissal from the job)and i got used to it. A doctor dealing with head trauma in the ER probably has his/her own views…