Helmets work -- work to create brain injury that is. Picture this: you're traveling downhill at about 30-mph through an "S-curve"... through some series of irrelevant events, you find yourself falling over. Your helmeted head hits the ground and immediately upon contact the soft foam grabs onto the rough asphalt and applies a mighty torsion, wrenching your brain and causing you to pass out... whereas, an unhelmeted head would have bounced and slid with far less of the damaging torsion to the brain...


(PS -- this is a devil's advocate point of view; I do personally wear a helmet, but I don't think the benefits of helmet use have been proven, especially not in this thread...)