A friend of mine (Bill) has chosen to ride with a helmet, or at times without a helmet. He says it depends upon riding conditions for him. One day he was on a two lane road, traveling about 50mph when a tractor trailer truck pulled out from the right side of the street to go the same direction. His thought was to maintain his speed and simply pass the truck. [Which, most likely could be done.]NITROXIN Unfortunately the truck…