Colorado § 42-4-406 - Requirement of certification of emissions control for registration - testing for diesel smoke opacity compliance.
Full text of Colorado Colorado Revised Statutes § 42-4-406 — Requirement of certification of emissions control for registration - testing for diesel smoke opacity compliance., with citation guidance and answers to common questions.
§ 42-4-406. Requirement of certification of emissions control for registration - testing for diesel smoke opacity compliance.
(1) (a) A diesel vehicle in the program area that is registered or required to be registered pursuant to article 3 of this title, routinely operates in the program area, or is principally operated from a terminal, maintenance facility, branch, or division located within the program area shall not be sold, registered for the first time, or reregistered unless such vehicle has been issued a certification of emissions control within:
(I) The past twelve months if the motor vehicle is a heavy-duty diesel vehicle that is over ten model years old;
(II) The last twenty-four months if the motor vehicle is a heavy-duty diesel vehicle that is ten model years old or newer;
(III) The last twelve months if the motor vehicle is a light-duty diesel vehicle that is at least ten model years old or that is model year 2003 or older; or
(IV) The last twenty-four months if the motor vehicle is a light-duty diesel vehicle that is ten model years old or newer and that is model year 2004 or newer.
(b) (I) A certification of emissions control shall be issued to any diesel vehicle that has been inspected and tested pursuant to subsection (2) of this section for diesel smoke opacity compliance and was found at such time to be within the smoke opacity limits established by the commission.
(II) Notwithstanding subparagraph (I) of this paragraph (b), new diesel vehicles, required under this section to have a certification of emissions control, shall be issued a certification of emissions compliance without inspection or testing. Prior to the expiration of the certification, the owner shall have the vehicle inspected and shall obtain a certification of emissions control for diesel smoke opacity compliance. The certificate shall expire on the earliest to occur of the following:
(A) The anniversary of the day of the issuance of the certification when the vehicle has reached its fourth model year if it is a light-duty diesel vehicle;
(B) The anniversary of the day of the issuance of the certification when the vehicle has reached its fourth model year if it is a heavy-duty diesel vehicle;
(C) The anniversary of the day of the issuance of the certification when the vehicle has reached its sixth model year if the vehicle has a gross vehicle weight rating of twenty-six thousand pounds or more and it is of a model year of 2014 or newer; or
(D) On the date of the transfer of ownership if the date is within twelve months before the certification would expire under sub-subparagraph (A), (B), or (C) of this subparagraph (II), unless the transfer of ownership is a transfer from the lessor to the lessee.
(2) (a) On or after January 1, 1990, all heavy duty diesel vehicles in the program area not subject to the provisions of section 42-4-414, with fleets of nine or more, shall be required to be tested for diesel smoke opacity compliance at a licensed diesel inspection station by submitting to loaded mode opacity testing utilizing dynamometers or on-road tests as prescribed by the commission.
(b) Light-duty diesel vehicles in the program area shall be required to be tested for diesel smoke opacity compliance at a licensed diesel inspection station by submitting to loaded mode opacity testing utilizing dynamometers.
Source: L. 94: Entire title amended with relocations, p. 2319, § 1, effective January 1, 1995. L. 95: (1)(a) amended, p. 954, § 11, effective May 25. L. 97: (1)(b)(II) amended, p. 120, § 1, effective August 6. L. 2003: (1)(a), (1)(b)(II), and (2)(b) amended, p. 1024, § 3, effective August 6. L. 2004: (1)(b) amended, p. 252, § 1, effective July 1. L. 2006: (1)(a) and (1)(b)(II)(A) amended, p. 915, § 1, effective July 1, 2007. L. 2015: (1)(b)(II) amended, (HB 15-1134), ch. 172, p. 541, § 1, effective August 5.
Editor's note: This section is similar to former § 25-7-604 as it existed prior to 1994, and the former § 42-4-406 was relocated to § 42-4-507.
Source: official Colorado text · Last verified 2026-08-27
Frequently Asked Questions About Colorado § 42-4-406
What does Colorado Revised Statutes § 42-4-406 cover?
Section 42-4-406 ("Requirement of certification of emissions control for registration - testing for diesel smoke opacity compliance.") is part of the Colorado Revised Statutes, the codified statutory law of Colorado. It sets out the legal rule or procedure described in the text above. Statutes are amended regularly, so always verify against the official source.
How do I cite Colorado § 42-4-406?
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Is this the official text of Colorado law?
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How does Colorado § 42-4-406 apply to my situation?
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