Washington, D.C. – National Park Service officials say they chose the stricter of two ways to test snowmobile emissions for Yellowstone and Grand Teton National Parks. Final rules were filed Tuesday and are expected to be published Thursday. Conservationists are already attacking them and say the agency ignored thousands of people who said they don't want snowmobilers in the parks. Environmental groups favor a plan written by the Clinton administration to phase out the machines in favor of snowcoaches. They've asked a court to reinstate the plan and a federal judge is deciding whether the Bush administration acted appropriately in setting it aside. A hearing is set for Monday. The snowmobiling season is scheduled to start December 17th.