The use of snowmobiles in Yellowstone and Grand Teton National Parks has been a topic of ongoing concern because of their impact on park resources. In 2003, the National Park Service (NPS) groomed over 180 miles of park roads at least every other night. As many as 1,700 snowmobiles enter the parks on peak days. The Fund for Animals and other environmental groups objected to the snowmobile use, and in December 2000, the NPS issued a proposed rule that capped snowmobile use in the winters. The NPS received 5,273 comments during the 30-day public comment period; over 4,300 of these comments supported the proposed rule. The NPS published the final rule. The 2001 Rule, promulgated during the Clinton administration, was published the day after President George W. Bush took office and was immediately stayed pending a review by the new administration. Meanwhile, the International Snowmobiler Manufacturers Association filed suit, challenging the rule as an unsupported decision. The NPS settled the litigation and agreed to consider data on new snowmobile technologies. NPS then issued another proposed rule. NPS received over 350,000 pieces of correspondence from the public; over 80 percent of the public comments supported the phase-out of snowmobiles. Despite this opposition, the NPS released a final rule delaying the implementation of the phase-out for an additional year. The Fund for Animals filed suit, challenging the postponement as arbitrary and capricious. Should the Fund win? Is the postponement arbitrary and capricious? In 2007, former National Park Director Fran Mainella called for using science, including studies of their impact, to make the rules on snowmobile use in national parks. Why is her recommendation relevant?