On this page: Overview | Proposals for regulatory changes | Public meetings | Resources | Contact us
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Overview
The CDPHE Air Pollution Control Division works to reduce air pollution from mobile sources through a variety of innovative programs. Emissions from motor vehicles are a major contributor to air pollution in Colorado. In 2024, the division plans to propose changes to Colorado’s regulations regarding vehicle inspection programs. These include Colorado Air Quality Control Commission Regulations 11 and 12.
In October 2024, the division will request rulemakings on updates for both regulations. If the Air Quality Control Commission approves the request during its October 2024 meeting, the hearings will be during its January 2025 meeting.
Proposals for regulatory changes
Regulation 11, Automobile Inspection and Readjustment (AIR) program
The division plans to propose changes to Regulation 11 that would impact owners of gasoline-powered vehicles in the Front Range area of Colorado that includes all or portions of Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Jefferson, Larimer, and Weld counties. Those owners would have access to self-service kiosks for On-Board Diagnostics (OBD) emissions tests that would be available 24/7 at convenient locations. The goal is to ensure that the state's vehicle emissions program remains effective in reducing air pollution and protecting public health. Heavy-duty trucks from model year 2008 and newer would switch from the Two-Speed Idle (TSI) test to the OBD test, ensuring a more accurate evaluation of nitrogen oxides (NOx) emissions. This is important because NOx emissions are a major contributor to ground-level ozone pollution in Colorado.
If Colorado adopts the changes in January 2025, the division would then establish a new online technical library. The library would provide detailed specifications and resources related to the Motor Vehicle Emissions Inspection Program.
The division’s plans to propose changes including:
- Enhanced and modernized vehicle emissions testing process in Colorado.
- New technology that improves testing efficiency, procedures, accessibility, and accuracy of testing.
Regulation 12: Reduction of Diesel Vehicle Emissions
The division plans to propose changes to Regulation 12 that would impact owners of diesel-powered vehicles in the Diesel Program Area which includes all or portions of Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, El Paso, Jefferson, Larimer, and Weld counties. Regulation 12 Parts A and B require operators of diesel fleets with 9 or more vehicles that self-test and certify compliance to use certain procedures and meet requirements for private testing stations.
The proposed changes to Part A would add:
- A visual inspection for emission control components for self-certification test vehicles.
- Training and qualification requirements for self-certification inspectors consistent with the requirements in Part B.
The division is also considering proposing:
- New, more stringent opacity requirements in Parts A, B, and C to reflect the performance capabilities of newer diesel vehicles.
- Additional procedures designed to identify tampering as a result of engine replacements.
- Various clean-up of existing provisions to improve readability and clarity of the requirements.
- The division’s goal with proposing changes to Regulation 12 is to modernize and enhance the diesel vehicle emissions testing process in Colorado.
Public meetings
In September 2024, the division is holding public meetings to discuss proposing changes to Regulations 11 and 12. The division will consider any feedback received during these meetings while preparing rule proposals.
Language interpretation services are available upon request. Registration is required.
- Virtual meeting: Tuesday, Sep 17, 2024, 10 a.m.-12 p.m.
- Virtual meeting: Wednesday, Sep 18, 2024, 6-8 p.m.
- Virtual meeting: Saturday, Sep 21, 2024, 10 a.m.-12 p.m.
Resources
- Register a vehicle in Colorado.
- Emissions inspections for gasoline-powered vehicles.
- Emissions inspections for diesel-powered vehicles.
- Automobile Inspection and Readjustment (AIR) Program.
- Aftermarket catalytic converters.
- Emissions technical centers.
- Smoking vehicle hotline.
- Low and zero emission vehicles (LEV/ZEV).
- Clean Fleet Enterprise.
- Colorado Clean Trucks.
- Tampering of emissions controls systems is prohibited.
Contact us
Questions? Email cdphe_mobile@state.co.us.