Pursuant to the Energy Policy and Conservation Act of 1975 (EPCA), the Final Rule sets corporate average fuel economy (CAFE) standards for light 'trucks, defined by NHTSA to include many Sport Utility Vehicles (SUVs), minivans, and pick-up trucks, for Model Years (MYs) 2008-2011. For MYs 2008-2010, the Final Rule sets new CAFE standards using its traditional method, fleet-wide average (Unreformed CAFE). For MY 2011 and beyond, the Final Rule creates a new CAFE structure that sets varying fuel economy targets depending on vehicle size and requires manufacturers to meet different fuel economy levels depending on their vehicle fleet mix (Reformed CAFE). Ps challenge the Final Rule under the EPCA and the National Environmental Policy Act (NEPA). Ps claim it is arbitrary, capricious, and contrary to the EPCA. Ps claim in part that it is inadequate under NEPA because it fails to take a 'hard look' at the greenhouse gas implications of its rule-making and fails to analyze a reasonable range of alternatives or examine the rule's cumulative impact. D claims that the Environmental Assessment's evaluation of the environmental consequences of its action is adequate, and an Environmental Impact Statement is not required.