I have been hit by mountain bikes several times and have had some very close calls - escapes! My friend had her collar bone broken by a mountain biker. They are adrenaline junkies and are devastating to the wilderness. They need to be banned, not encouraged. Of course National profits from their ads in SIERRA magazine, so they have a conflict of interest. Mountain bikers have, and continue, to oppose new Wilderness areas has their machines would be excluded and they would have to walk.