Congress passed the 1964 Wilderness Act in order to preserve and protect certain lands 'in their natural condition' and thus 'secure for present and future generations the benefits of wilderness.' Congress directed that designated wilderness areas 'shall be administered for the use and enjoyment of the American people in such manner as will leave them unimpaired for future use and enjoyment as wilderness, and so as to provide for the protection of these areas, the preservation of their wilderness character, and for the gathering and dissemination of information regarding their use and enjoyment as wilderness.' Cumberland Island was designated as wilderness or potential wilderness some 19,000 acres, including most of the northern three-fifths of the island. The Park Service thus became responsible for administering the wilderness area 'in accordance with the applicable provisions of the Wilderness Act.' Park Service land includes several buildings and facilities on the southern end of the island as well as two historical areas on the northern and western coasts: Plum Orchard, just outside the wilderness boundary, and the Settlement, located in potential wilderness area. These two locations have been reached via a one-lane dirt road that has also been designated as part of the wilderness and potential wilderness areas. The Wilderness Act places severe restrictions on commercial activities, roads, motorized vehicles, motorized transport, and structures within the area, subject to very narrow exceptions and existing private rights: there shall be no commercial enterprise and no permanent road within any wilderness area designated by this chapter and, except as necessary to meet minimum requirements for the administration of the area for the purpose of this chapter (including measures required in emergencies involving the health and safety of persons within the area), there shall be no temporary road, no use of motor vehicles, motorized equipment or motorboats, no landing of aircraft, no other form of mechanical transport, and no structure or installation within any such area. The Park Service continued to use the existing one-lane dirt road to access the historical areas. Motorized transportation on Cumberland Island became a controversial issue in the 1990s, as the federal government sought to obtain remaining private tracts on the island and various groups called for greater public access to and support of the historical sites. The Park Service claimed that it needed motorized access to the historical areas in order to 'meet its obligations to restore, maintain, preserve and curate the historic resources . . . and permit visitor access and interpretation.' It acquired a fifteen-person van in order to accommodate larger numbers of visitors and offered trips to Plum Orchard three times per week and to the Settlement once per month. Ps sued D over this usage, and the trial court granted summary judgment to Ds. Ps appealed.