(a) Section numbering. (1) The model year of initial applicability is indicated by the last two digits of the 5-digit group. A section remains in effect for subsequent model years until it is superseded. The number following the hyphen designates what previous section is replaced by a future regulation.
Examples: Section 86.077-6 applies to the 1977 and subsequent model years until superseded. If a Sec. 86.080-6 is promulgated it would take effect with the 1980 model year; Sec. 86.077-6 would not apply after the 1979 model year. Section 86.077-10 would be replaced by Sec. 86.078-10 beginning with the 1978 model year.
(2) Where a section still in effect references a section that has been superseded, the reference shall be interpreted to mean the superseding section.
(b) A section reference without a model year suffix refers to the section applicable for the appropriate model year.
(c) Construction. Except where indicated, the language in this subpart applies to both vehicles and engines. In many instances, language referring to engines is enclosed in parentheses and immediately follows the language discussing vehicles. [45 FR 63747, Sept. 25, 1980, as amended at 59 FR 48492, Sept. 21, 1994]