Other states
It's interesting when this problem comes up, you can always count on someone writing something like: "In (insert any state but NJ) they have places for people to ride so they don't destroy sensitive areas. When NJ fulfills it's promise to build the ATV parks the problem will stop".
This past weekend I visited Shenk's Ferry Wildflower Preserve in PA to photograph some early spring species. The area surrounding the preserve is torn all to Hell by ATV traffic, dirt bikes, and mudboggers. Right at the entrance to the preserve trail, a dirt bike had climbed a hill covered in emergent Dutchman's Britches and ripped up many of the plants. I talked to some volunteers who were doing trail maintenance and they said there were plenty of legal places to ride, but it's an ongoing problem with motorcycles and ATV tearing up trail in the clearly posted and gated preserve. The alternate access road to the preserve is no longer passable in a street car due to it being torn up by ORV's.