On April 24, 2015, the United States Court of Appeals for the District of Columbia Circuit decided the case of Delta Construction Company, et. al. v EPA, denying petitions requesting the court's review of rules jointly issued by EPA and the National Highway Traffic Safety Administration regulating greenhouse gas emissions and mandating fuel economy rules affecting cars and trucks (the court describes these two rules as "the Car Rule" and the "Truck Rule"). In 2012, the Court of Appeals upheld the "Car Rule" in Coalition for Responsible Regulation, Inc., v. EPA, 684 F. 3d 102, reversed in part by the Supreme Court in Utility Air Regulatory Group v. EPA, 134 S.Ct. 2427 (2014).

In the Delta Construction Company case, the various petitioners mounted a collateral attack on the Car Rules on procedural grounds and the Truck rules on similar grounds. Another petitioner, Plant Oil Powered Fuel Systems (POP Diesel), which makes after-market modifications to diesel engines and promotes the use of vegetable oil in place of diesel fuel, argued that these rules make its products economically infeasible. As so often happens, the Court of Appeals held that none of the petitioners had standing to seek review. Indeed, POP Diesel, was obliged to adhere to the special requirements of the federal transportation laws, and it failed to do so. Accordingly, since 49 U.S.C. § 32909, does not permit a direct review in the courts of appeals, it lacked standing.

Another panel of the Court of Appeals decided the case of Myersville Citizens for Rural a Community, Inc., v. Federal Energy Regulatory Commission on April 24, 2015. This is the second time the Court of Appeals has reviewed the expansion plans of Dominion Transmission, Inc., an operator of natural gas storage and transmission facilities serving several northeastern states. FERC authorized the construction of a natural gas compressor station in Myersville, Maryland, and this facility has now been in operation for several months. Judge Millet, writing for a unanimous court, held that FERC's decision to issue a Certificate of Public Convenience and Necessity to Dominion was supported by substantial evidence, and that the Federal Energy Regulatory Commission's analysis of pertinent procedural and economic factors was thorough and persuasive.

In the earlier case, Dominion Transmission, Inc., v. Summers, 723 F. 3d 238 (2013), the Court of Appeals essentially rebuked the Maryland Department of the Environment for failing to process Dominion's application for the necessary air quality permit, and remanded the matter to the Department. In 2014, the Department finally granted the permit, and in this ruling, the Court of Appeals holds that the Commission has not undermined the Clean Air Act by issuing the certificate. Lastly, the Court of Appeals rejected the petitioners' complaints about FERC's adherence to the requirements of National Environmental Policy Act (NEPA) in conducting an environmental review of the project.