I hate to be a negative nancy but going that fast on dirt roads is retarded unless you're in a wide open area... As a dirtbiker I try not to ride on dirt roads too often, but sometimes I need to take them in order to get back onto a trail. I've nearly been hit a couple times by douchebags who are going too fast and push wide on a blind corner, totally out of control. Although there aren't technically rules to abide by when offroad, try to use common sense and realize that other people are out there trying to have fun- also wanting to return home at the end of the day.