YELLOWSTONE NATIONAL PARK, Wyo. » Maintenance crews have begun plowing roads in Yellowstone National Park as the park prepares to open for automobile traffic in the spring.

Park officials gradually will end snowmobile and snow coach travel on the park's interior roads by March 15.

Over-snow travel from Mammoth Hot Springs to Norris Junction and from the park's East Entrance to Fishing Bridge ended Sunday.

Travel between Madison, Norris and Canyon Village ends Tuesday. Over-snow travel on the road from Canyon through the Hayden Valley to Fishing Bridge concludes next Sunday. Travel from West Yellowstone, Mont., and the South Entrance to Old Faithful ends March 15.

The park's interior roads reopen to automobile travel between mid-April and the end of May.