"Unfortunately, helmets are pretty lousy at preventing concussion. They protect your head the same way egg cartons protect eggs - the shell is the part that is actually being protected not the yoke. Which means helmets do a good job of protecting your skull from fracture and puncture but little to prevent your brain from bouncing around in your skull resulting in a concussion. People should be made aware of this - helmets don't prevent concussion. That said, I've been in several accidents on both bicycles and motorcycles. In every accident, my head hit the ground (protected by a helmet). I gladly wear a helmet to protect the integrity of my skull any day.  Your skull loses every time when competing with concrete. Though it is definitely a personal choice to wear a helmet, if you don't you're unwittingly increasing your chances of joining the ranks of the Darwin awards and make sure you're signed up to be an organ donor.  "