A divided federal appeals court has thrown out portions of the 2016 Phase 2 greenhouse gas emissions truck rule that would have required heavy- and medium-duty tractor truck trailers for the first time to adopt some combination of fuel-saving technologies. Circuit Judge Justin Walker of the U.S. Court of Appeals for the District of Columbia Circuit, wrote in the decision Friday, \u201cTrailers have no motor. They are therefore not \u2018motor vehicles.\u2019 Nor are they \u2018vehicles\u2019 when that term is used in the context of a vehicle\u2019s fuel economy, since motorless vehicles use no fuel.\u201d The rule would have required trailer manufacturers to adopt some combination of fuel-saving technologies, such as side skirts and automatic tire pressure systems. The decision came in a petition for the court\u2019s review of the rule requested by the Truck Trailer Manufacturers Association.\nLearn more about your ad choices. Visit podcastchoices.com/adchoices