CHEYENNE, Wyo. -

The National Park Service is ready to release its latest proposal on snowmobile use in Yellowstone National Park.
    
The agency has been studying and taking comment on an initial plan to allow up to 480 snowmobiles plus 60 multiple passenger snow coaches per day into Yellowstone during the winter. It's set to announce its latest proposal Friday.
    
The new proposal will be subject to more public review before a final decision is made.
    
The park has been operating in recent winters with a daily limit of 318 snowmobiles and 78 snow coaches.
    
The state of Wyoming and snowmobile groups want the park to allow more snowmobile access, while some conservation groups want snowmobiles banned from the park.
    
The issue has been the subject of court challenges for about a decade.