CFR›Title 49›Subtitle B›Chapter V›Part 531 ContainsSections 531.1–531.6; Appendix ACorpusDaily eCFRDisplayed edition2026-04-15Last updated2026-04-15 PART 531—PASSENGER AUTOMOBILE AVERAGE FUEL ECONOMY STANDARDS Contents 531.1 § 531.1 Scope. 531.2 § 531.2 Purpose. 531.3 § 531.3 Applicability. 531.4 § 531.4 Definitions. 531.5 § 531.5 Fuel economy standards. 531.6 § 531.6 Measurement and calculation procedures. Appendix A to Part 531 Appendix A to Part 531—Example of Calculating Compliance Under § 531.5(c) Authority49 U.S.C. 32902, delegation of authority at 49 CFR 1.95.Source87 FR 26070, May 2, 2022, unless otherwise noted. Previous 529 Part 529—Manufacturers of Multistage Automobiles Next 533 Part 533—Light Truck Fuel Economy Standards