I keep posting on the motorcycle forums that the inertial mass of a heavy helmet prevents you from snapping your head side to side for a check of any incoming vehicles at intersections. Mainly controlled intersections where the majority of two vehicle collisions take place. I was sitting at a light and a motorcycle came ripping up between the lanes -- a Hawthorne Police Motorcycle. I started recording and sure enough, as the light went green the motorcyclist immediately started forward without looking to the sides. You cannot AVOID an collision is you do not see the incoming vehicle.