Motor vehicle emissions limitations; inspections
Wis. Stat. § 285.30
in effect(1) Definitions. As used in this section, unless the context requires otherwise:
(a) “Federal act” means the federal clean air act, 42 USC 7401 et seq., and regulations issued by the federal environmental protection agency under that act.
(b) “Motor vehicle” has the meaning designated under s. 340.01 (35).
(2) Limitations. The department shall adopt rules specifying emissions limitations for all motor vehicles not exempted under sub. (5). The limitations may be different for each size, type and year of vehicle engine affected and may not be more stringent than those required by federal law at the time of the vehicle’s manufacture. The limitations shall be adopted and periodically revised upon consideration of the following factors:
(a) The emissions reductions necessary to achieve federally mandated ambient air quality standards by any deadline established by the federal act and to maintain those standards after any deadline established by the federal act.
(b) The emissions levels attainable by reasonable preventive maintenance practices relating to installed emission control equipment and devices for each model year, size and type of motor vehicle affected.
(c) The requirements for eligibility for a manufacturer’s warranty under section 7541 (b) of the federal act.
(d) The requirements of the federal act.
(3) Counties where inspections required. If the department finds that air quality within a county will not meet one or more applicable primary or secondary ambient air quality standards by any deadline established by the federal act, or that these standards will not be maintained in the county after any deadline established by the federal act and that inspection of emissions from motor vehicles in any part of the county is required by federal law to attain or maintain these standards, the department shall certify this finding to the department of transportation.
(4) Termination. If the department finds that air quality within a county specified in a certification under sub. (3) has attained all applicable ambient air quality standards and that these standards will be maintained in the county or that control of motor vehicle emissions is no longer required by federal law for attainment and maintenance of these standards, the department shall notify the department of transportation that the county is withdrawn from the certification under sub. (3).
(5) Exemptions. Emissions limitations promulgated under sub. (2) do not apply to the following motor vehicles:
(a) A motor vehicle of a model year of 1995 or earlier.
(b) A motor vehicle of a model year of 2006 or earlier that has a gross vehicle weight rating exceeding 8,500 pounds, as determined by the manufacturer of the vehicle, and a motor vehicle of a model year of 2007 or later that has a gross vehicle weight rating exceeding 14,000 pounds, as determined by the manufacturer of the vehicle.
(c) A motor vehicle exempt from registration under s. 341.05, except that a motor vehicle owned by the United States is not exempt unless it comes under par. (a), (b), (d), (e), (f), (g), (h), (j), (k), or (m).
(d) A motor vehicle of a model year of 2006 or earlier that is powered by diesel fuel.
(e) A new motor vehicle not previously registered in any state.
(f) A motor vehicle for which inspection, in the judgment of the department, is not a cost effective method for attaining and maintaining air quality.
(g) A moped as defined in s. 340.01 (29m).
(h) A motorcycle as defined in s. 340.01 (32).
(i) A farm truck as defined in s. 340.01 (18) (a).
(j) An off-road utility vehicle as defined in s. 340.01 (38m).
(k) A low-speed vehicle, as defined in s. 340.01 (27h).
(L) A lightweight utility vehicle as defined in s. 346.94 (21) (a) 2.
(m) An autocycle, as defined in s. 340.01 (3m).
(6) Tampering with pollution control system or mechanism.
(a) Definitions. As used in this subsection:
1. “Air pollution control equipment” means any equipment or feature which constitutes an operational element of the air pollution control system or mechanism of a motor vehicle.
3. “Tamper” means to dismantle, to remove without replacing with an identical or comparable tested replacement device or to cause to be inoperative any air pollution control equipment.
(b) Prohibition. Except as permitted or authorized by rule of the department, no person may fail to maintain in good working order or may tamper with air pollution control equipment.
(c) Ineligibility for motor vehicle registration. Except as permitted or authorized by rule of the department, if any person tampers with the air pollution control equipment of a motor vehicle, that vehicle is ineligible for motor vehicle registration until the air pollution control equipment is replaced, repaired or restored to good working order.
(d) Suspension or cancellation of motor vehicle registration. Except as permitted or authorized by rule of the department, if the owner of a motor vehicle tampers with or causes or knowingly permits any person to tamper with the air pollution control equipment, the motor vehicle registration for that vehicle may be suspended or canceled in addition to any other penalty provided by law.
(e) Rule making. The department shall promulgate rules that specify the requirements for the inspection of motor vehicles for the occurrence of tampering with air pollution control equipment.
Source: WI Statutes (Official Site)URL: https://docs.legis.wisconsin.gov/document/statutes/285.30Fetched: 10/7/2026