Diesel Vehicles

Diesel Emissions Program
The full counties of Boulder, Jefferson, Broomfield, Denver, and Douglas, and portions of Adams, Arapahoe, Larimer, Weld, and El Paso counties require a passing emission test to register a vehicle. See our map for testing locations and diesel emissions area boundaries.  If you are unsure if a diesel test is required in your area, please contact your local county motor vehicle office.