On December 27, 2016, U.S. Customs and Border Protection (CBP) published a Final Rule in the Federal Register announcing amendments to CBP regulations relating to the importation into the United States of certain vehicles and engines under the Clean Air Act (CAA) in order to harmonize the documentation requirements applicable to different classes of vehicles and engines that are subject to the CAA's emission standards. That document further amended the regulations to permit importers to file the required U.S. Environmental Protection Agency (EPA) Declaration Forms with CBP electronically, and amended non- substantive provisions to update regulatory citations and delete obsolete provisions. The changes announced in that Final Rule were to be effective January 26, 2017. This notice announces that the effective date of the Final Rule is delayed for 60 days from January 20, 2017.