US lawFederal (United States)RegulationsTitle 49 CFR — TransportationChapter V — NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATIONPart 531 — PASSENGER AUTOMOBILE AVERAGE FUEL ECONOMY STANDARDS531.349 C.F.R. § 531.3Applicability.Last amended: 2016Year: 2026Length: 8 wordsOfficial source Cite as 49 C.F.R. § 531.3 (2026)This part applies to manufacturers of passenger automobiles.Previous49 C.F.R. § 531.2Next49 C.F.R. § 531.4