CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER C—AIR PROGRAMS (Parts 50–99) > PART 86—CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES > SUBPART I—Emission Regulations for New Diesel Heavy-Duty Engines; Smoke Exhaust Test Procedure (§86.884-1 to §86.884-14) > 86.884-4—Section numbering.