When gasoline vehicles are 7-years-old, they must pass an emissions inspection in order to be registered in Boulder County (4-years-old for diesel vehicles.) Testing is required when a gasoline vehicle changes ownership in their 7th model year or later (even if there is time left on the previous test) and for registration renewal, if indicated on the renewal notice.
The following vehicle types do not require emissions testing:
- Motorcycles
- All-electric vehicles
- Gas-fueled or hybrid vehicles within the first seven model years
- Diesel-fueled vehicles with GVWR under 26,000 pounds are exempt for the first four model years
- Diesel-fueled vehicles with GVWR 26,000 pounds or more are exempt for the first six model years
- Vehicles 1975 and older with collector plates
- Kit cars
- Horseless carriages
- Vehicles registered as farm trucks
- Vehicles registered as street rods
