That's a common regulation everywhere in the country on public lands.
And around here, a traditional glasspack is most definitely NOT a spark arrestor. In fact, the old ones, especially as they wear down, are one of the worst offenders and one of the reasons that 4-wheel vehicles get inspected for spark arrestors on park lands like motorcycles do.
As they age, glasspacks actually spew out small particles of hot glass mat and metal as they deteriorate. The big concern is obviously starting a forest fire.
Not sure the exact regulations, or even if they're the same for every state park, but I bet the national parks are pretty well consistently regulated. Maybe even BLM land? Not sure about that, but someone in Moab would likely know, since there is a lot of public, private and BLM land in the area that gets wheeled heavily.
If you go to an OHV park that's fairly well stocked with Rangers and park personnel you'll likely get checked for that type of stuff. Pretty much anything with a baffle is ok, but if it's a straight-through glasspack, they may question whether or not it's really a glasspack, or like some modern ones, a steel mesh design, which is probably ok in some books.
They really look down on short exhaust with turn-downs and turn-outs especially. I suppose if you've got a super long full length system with twists and turns but still have glassplacks, someone may not question it. Hard to say though, until you try.
If you're in an area not known for fires (lots of moisture and green foliage) then maybe the same rules don't apply. But out here and in other dry states, it's definitely frowned upon.
Paul
