Our local state run OHV park has seperate motorcycle and 4wd areas (CA) The park officials and 4wd groups have agreed to allow trials bikes in the 4wd area but do not want the MXers in there. The difficult part is how to designate the area for 4wd and trials only. Enforcement could be a major issue. Does anything like this exist elsewhere? How is it handled? (So far, Trials specific tires seem to be the best choice.)