Provisions for diesel fuel transported into the U.S. by truck or rail car are found in § 80.583. They are similar to the gasoline sulfur rule provisions for importing gasoline into the U.S. by truck.
Question and Answer was originally posted at Questions and Answers on the Clean Diesel Fuel Rules (PDF)(135 pp, 888 K, EPA420-B-06-010, July 2006, About PDF)