Colorado Department of Revenue
Text  Increase Text SizeDecrease Text Size

Diesel Vehicles


Diesel Gas Pump


Diesel Emissions Program Area


The full counties of Boulder, Jefferson, Broomfield, Denver, and Douglas, and the partial counties of Adams, Arapahoe, Larimer, Weld, and El Paso.


A quick reference map is available here. If you are unsure of whether or not a diesel test is required in your area, please contact your local county motor vehicle office.


Cost and Locations


The diesel emission testing facilities can charge up to one-hour of the posted labor rates.  There is no set fee.


Find a testing station by clicking here for a list or here for a map.




Diesel Vehicle Emissions Testing Cycles
Vehicle Type
How Often Test is Required


New light-duty or new heavy-duty in the first four model years

(if the vehicle is being sold in its last year of exemption, it requires an inspection for sale)




Light-duty 2004 and newer but more than four years old




Heavy-duty less than ten years old but more than four years old


Every two years



Light-duty 2003 and older


Heavy-duty ten years old


Every year


Diesel Vehicle Gross Vehicle Weight Ratings (GVWR) Definitions

Light-duty diesel vehicle

GVWR of 14,000 lbs. or less

Heavy-duty diesel vehicle

GVWR of 14,001 lbs. or more