During the final year of the Clinton Administration, proposals by the National Park Service to enforce long-standing policies that regulated the use of snowmobiles in national parks raised a number of questions regarding the potential regulation of such vehicles. These questions continue to be debated, as the National Park Service (NPS) explores optional winter use plans for Yellowstone and other units of the national park system, and as various parties challenge the actions of the NPS in court. National Park System units account for only about 3% of the land mass of the United States and possess few trails and roads suitable for snowmobiles, compared to areas available on other federal lands; but—for both proponents and opponents—the question of snowmobile access to the parks has taken on a far greater importance. To the snowmobile industry and to many in communities neighboring national parks, "Snowmobiling is an important part of the economic engine that supports northern communities, winter tourism." To environmental groups, snowmobiling "is one of the most environmentally devastating recreational activities permitted by the Park Service .... resulting in adverse impacts to Park wildlife, air and water quality, vegetation, Park ecology, and Park users." Underlying the debate are broader questions concerning regulation of emissions and noise from the vehicles and the degree to which restrictions may serve as a precedent or stigma affecting snowmobile and motorized recreation use more generally. In the 1990s, snowmobiles were allowed access to 43 units of the National Park System, including such major parks as Yellowstone, Grand Teton, Rocky Mountain, Acadia, Zion, Mount Rainier, and Sequoia. While numerous park units allowed such access, recreational use of snowmobiles has not been widespread in the park system as a whole. The National Park Service administers 391 units (parks, seashores, monuments, etc.). Of these, 348 (89%) have not been open to snowmobiles. Many units are located in climates unsuitable for them or are too small to be used for such recreation. Others (e.g., Glacier National Park and Yosemite) have banned snowmobiles since the 1970s. According to the National Parks Conservation Association, use of snowmobiles outside of Alaska has mostly been concentrated in five units of the park system: Yellowstone National Park, Voyageurs National Park, Rocky Mountain National Park, Pictured Rocks National Lakeshore, and the John D. Rockefeller Memorial Parkway. Yellowstone accounted for about 40% of the snowmobile visitors at these five parks, with a total of 76,571 in the 1999-2000 winter season. Comparative data for all five of these units are not available for years after 1999-2000. One of the five, Rocky Mountain National Park, has closed all but one snowmobile route since 2004—the one route remaining being a 2-mile trail that provides access to National Forest land heavily used by snowmobiles. Snowmobile visits to Yellowstone increased during the 2000-2001 and 2001-2002 winter seasons, peaking at 87,206 in the latter winter. In subsequent years, snowmobile visitors to Yellowstone plummeted, to a low of 24,049 in 2004-2005. Changes in access policy (described later in this report) as well as drought and low snow pack in recent years contributed to the decline. Two other Yellowstone area park units, Grand Teton National Park and the Rockefeller Memorial Parkway, experienced an even more steep decline, from a combined 35,000 snowmobile visits in 2000-2001 to about 7,500 in 2004-2005. Snowmobile visits have rebounded somewhat since 2004-2005, but in 2007-2008 they remained at only about 35% of visits in the peak years. Although recreational access by snowmobiles has been permitted in units of the national park system, the Park Service, in the late 1990s, concluded that such use has generally been in violation of Executive Orders 11644 and 11989, issued by Presidents Nixon and Carter respectively. The Nixon Order directed that use of off-road vehicles on public lands "be controlled and directed so as to protect the resources of those lands, to promote the safety of all users of those lands, and to minimize conflicts among the various uses of those lands." It specified that off-road vehicle "areas and trails shall be located in areas of the National Park system ... only if the respective agency head determines that off-road vehicle use in such locations will not adversely affect their natural, aesthetic, or scenic values," and it directed the Park Service to "monitor the effects of the use of off-road vehicles" and to rescind or limit this use "as necessary to further the policy of this order." In January 1999, the Park Service received a rulemaking petition from the Bluewater Network and 60 other environmental organizations seeking a ban on snowmobiles from all units of the National Park Service. In response, the Service surveyed units of the System to assess the extent to which they were complying with the Executive Orders. According to Interior Department testimony: "The results graphically demonstrated that the National Park Service was not complying with its statutory and regulatory mandates.... Consequently, maintaining the status quo with regard to snowmobiling was simply not an option." On April 27, 2000, the Department of the Interior and the National Park Service announced that "snowmobiling for general recreational purposes will be prohibited throughout the Park System, with a limited number of narrow exceptions." By July 2000, the Department had backed away from its strict enforcement stance with a clarification: there would be no snowmobile ban in park units pending a formal rulemaking and public comment period, and snowmobile practices prior to the April 2000 announcement (i.e., access to more than 40 parks) would continue through the 2000-2001 winter season. NPS has taken no further action to enunciate a general policy. Since the summer of 2000, the focus has been on Denali National Park in Alaska and the Yellowstone/Grand Teton area. Both of these areas had been considered exceptions subject to special consideration even under the April 2000 policy announced by the Park Service. Whether snowmobile access to these parks will be allowed to continue has generated substantial public interest. In Alaska, vast distances, lack of roads, abundant snow cover, and small dispersed populations make snow machine use ubiquitous. In general, national parks in Alaska allow snowmobile access under the provisions of the Alaska National Interest Lands Conservation Act (ANILCA, P.L. 96-487 ). However, access to the 2 million acres formerly known as Mt. McKinley National Park (now the core of Denali National Park) has been an issue. Prior to passage of ANILCA (1980), snowmobiles had been banned from this park. In 1999, the Park Service reinstated this policy, banning snowmobiles first on a temporary and later on a permanent basis. Litigation regarding access to Denali was initiated by snowmobile user groups, but was withdrawn in June 2001, on the assumption that legislation would be introduced to address the issue. Legislation ( H.R. 4677 / S. 2589 , 107 th Congress) was introduced in the spring of 2002 that would have allowed access to some portions of the old Park, while continuing the ban elsewhere. No action was taken on these bills, however, and similar legislation has not been introduced in subsequent years. In January 2006, the National Park Service published a Final Backcountry Management Plan for Denali National Park and Preserve. The plan notes that as a result of technology improvements that have extended the range of snowmobiles, the use of such machines is now widespread in the southern park additions and "growing rapidly." "... [C]onflicts with other users, especially non-motorized winter recreationists and subsistence users, are increasing, and concerns have been raised about the effects of snowmachine use on wildlife, vegetation, water quality, air quality, natural soundscapes, and other park resources." Despite raising these issues, the plan concludes, "There are currently few guidelines for managing use." The other exception to the National Park Service's general policy was the Yellowstone/Grand Teton National Park area. The NPS had been sued in May 1997 by groups who alleged that the Service was violating the National Environmental Policy Act, the Endangered Species Act, the National Park Service Organic Act, and the Yellowstone Act in allowing use of snowmobiles in the two parks and on the Rockefeller Memorial Parkway (which links them). The lawsuit was settled within months when the NPS agreed to conduct an Environmental Impact Study (EIS) of winter use of the parks. Upon completion of the study, the Clinton Administration promulgated a final rule in January 2001, banning snowmobiles from Yellowstone, Grand Teton, and the Rockefeller Parkway beginning in the winter of 2003-2004, but allowing continued visitor access through the use of "snowcoaches"—guided tour-vans that run on rubber treads. Snowmobile manufacturers, represented by the International Snowmobile Manufacturers Association (ISMA), have suggested that "cleaner, quieter" snowmobiles—a phrase not initially defined—be allowed continued access to the parks. Their suggestion found a receptive audience in the Bush Administration. On June 29, 2001, the Administration responded to a suit filed by ISMA and the State of Wyoming by agreeing to reopen the decision to ban the vehicles from the three Yellowstone area units. The Park Service agreed to prepare a Supplemental EIS and reach a new Record of Decision by November 15, 2002 (a deadline subsequently extended to March 15, 2003). The Record of Decision was signed March 25, 2003, and a final rule implementing it was promulgated December 11, 2003.