Under the Clean Air Act, the Environmental Protection Agency (EPA) regulates vehicle emissions. Accordingly, the EPA developed regulations requiring vehicle manufacturers to test emissions of new vehicles using a "test fuel" that is "commercially available." The plaintiffs, a coalition comprised largely of ethanol producers, challenged the test fuel regulation as arbitrary and capricious because their fuel, which contains 30 percent ethanol, could not be a test fuel because it is not yet commercially available. They claimed that a fuel need not be commercially available in order to be approved as a test fuel. The court, in short order, dismissed the plaintiffs' arguments in that the regulation was solidly rooted in the statute requiring vehicles to be tested under circumstances that reflect actual current driving conditions. The court made no mention that fuel containing ethanol does not actually improve environmental quality as reported in the Proceedings of the National Academy of Sciences published in December of 2014 which reported that "the combined climate and air quality impacts [of corn-ethanol-fueled vehicles] are greater than those from gasoline vehicles." Energy Future Coalition, et al. v. Environmental Protection Agency, et al., No. 14-1123, 2015 U.S. App. LEXIS 12078 (D.C. Cir. Jul. 14, 2015).