How much money does an ATV owner put into state coffers with registration and taxes paid in gasoline? How much does pedestrians or bicyclists put in? Where's the benefit to ATV owners when their trails are graded and paved with signs up stating "no motorized traffic"?  If you want to play, you have to pay. Ante up and pay for your own trails.  

If you don't like the ATVs out in the valley, you could always move back to anchorage so you can be in a safe space.  Or Seattle, it's probably safer.