Kansas And Nebraska Challenge EPA's Vehicular Emissions Model

In October 2014, U.S. EPA released and published the MOVES2014 Motor Vehicle Emissions Model, an emissions model that states must use to craft future State Implementation Plans ("SIPs") and, starting in October 2016, to demonstrate that their transportation projects conform to their SIPs. See 79 Fed. Reg. 60343 (Oct. 7, 2014). In December 2014, the states of Kansas and Nebraska, and two environmental organizations, petitioned the United States Court of Appeals for the District of Columbia to strike down the model on procedural and substantive grounds. State of Kansas et al. v. Environmental Protection Agency et al., No. 14-1268.

Petitioners argued that EPA's promulgation of the model was procedurally flawed and violated the Administrative Procedures Act ("APA") because EPA implemented the model without providing the public notice or an opportunity for interested parties to comment. On the merits, petitioners alleged that the model was unsound because it was based, in