40 CFR § 86.404-78 - Section numbering.

---
identifier: "/us/cfr/t40/s86.404-78"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 86.404-78 - Section numbering."
title_number: 40
title_name: "Protection of Environment"
section_number: "86.404-78"
section_name: "Section numbering."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "C"
subchapter_name: "AIR PROGRAMS"
part_number: "86"
part_name: "CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401-7671q."
cfr_part: "86"
---


# 86.404-78 Section numbering.

(a) The year of initial applicability of a section is indicated by its section number. The two digits following the hyphen designate the first model year for which a section is effective. A section remains effective until superseded.

(b) A reference to a section without a year designation implies the appropriate model year.