The U.S. has been combatting emissions for decades, with the government recently vowing to reduce emissions in half by 2030. Each state has its own emissions goals to reach, and how they achieve that is up to the local government. With diesel vehicles frequently in the crosshairs of emissions regulations, the majority of states have begun to require some level of emissions testing.
What vehicles and how often these tests are required can differ from state to state, and the number of states that require emissions testing has slightly increased over the past six years. According to AAA, here’s the list of states that currently require some form of emissions testing.
1. Alaska – Every 2 years but only in designated areas (Fairbanks and Anchorage)
2. Arizona – An emissions inspection is required prior to registration. Areas are broken up into Area A and Area B, each with their own requirements.
3. California - Inspections are required for all vehicles except motorcycles or vehicles that were manufactured prior to the 1976 model year, and diesel-powered vehicles manufactured prior to the 1996 model year that have a gross vehicle weight of over 8,500 lbs. Vehicles that are registered in areas subject to the biennial smog certification program are required to submit evidence of a smog certification for every other renewal period.
4. Colorado - Emissions testing of both gas and diesel-powered vehicles is required when registering, re-registering, or selling vehicles in the counties (known as the Enhanced Areas) of Adams, Arapahoe, Boulder, Denver, Douglas, El Paso, and Jefferson. Testing is also required in Weld, Larimer, and Pitkin counties, known as the Basic Area. In the enhanced emissions areas, no vehicle that requires registration can be sold or registered for the first time without a certificate of emissions compliance or registered unless such vehicle passed a clean screen test.
5. Connecticut - All 1968 and later vehicles must have an effective air pollution control device. With limited exemptions, vehicles are inspected biannually for compliance.
6. Delaware - Emissions inspection is required for all vehicles manufactured since 1968. Those manufactured within the last five model years are exempt.
7. District of Columbia - Motor vehicles and trailers must have emissions tested biennially. New vehicles that have a certificate of origin, pre-1968 vehicles and zero-emission vehicles, are exempt.
8. Georgia – A yearly emissions inspection is required prior to registration in Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding, and Rockdale counties. All covered vehicles must have a current passing Certificate of Emission Inspection or waiver in order to get a vehicle registration each year.
9. Idaho – Determined by state and local ordinance but required in Ada and Canyon counties.
10. Illinois – Testing is dependent upon year of vehicle but annual testing required for in Cook, Dupage, Lake, parts of Kane, Madison, St. Clair, Will, Kendall, Monroe, and McHenry counties.
11. Indiana – Varies from county to county.
12. Kentucky – Testing is required in certain cities and counties.
13. Louisiana – Testing is required as part of safety inspections in designated areas.
14. Maine – Required for many original registrations and for annual registration renewals in Cumberland County.
15. Maryland – Vehicles are required to have an exhaust emissions test and misfuelling inspection every 2 years. Exceptions may apply for certain models and for motorcycles, Class E trucks with a GVW of over 26,000 lbs, historical vehicles, and cars prior to model year 1977.
16. Massachusetts – Safety and emissions tests are required every year for passenger cars, light trucks, and SUVs that are model 1997 and newer. Passenger vehicles model year 1999 and newer must also take annual emissions tests.
17. Missouri - Emissions and safety inspections are required biennially in St. Louis, St. Charles, Jefferson, Franklin, and the City of St. Louis counties. Some exceptions apply for older gasoline-powered and diesel-powered vehicles and newer motor vehicles.
18. Nevada – Only vehicles in the urban areas of Clark and Washoe Counties have required testing.
19. New Hampshire – 1996 and newer gasoline-powered and newer diesel-powered vehicles must have onboard diagnostics systems tested that meet EPA standards.
20. New Jersey – Most vehicles registered in New Jersey are required to have emissions inspections, with some classes of vehicles requiring biennial inspections.
21. New Mexico – Currently, only the city of Albuquerque and Bernalillo County require testing, but other counties or ordinances may have some standards as well.
22. New York – Required annually for all vehicles.
23. North Carolina – Required in 22 out of 100 counties for vehicles that are 1996 model year or newer, and that are either older than the three most recent model years or that have 70,000 miles or more.
24. Ohio - A motor vehicle inspection and maintenance program is currently in any county classified as moderate, serious, severe, or extreme nonattainment for carbon monoxide or ozone, with inspections required biannually.
25. Oregon - Vehicles from the 1975 model year and newer must be submitted for emissions inspection in the Portland Vehicle Inspection Area. For the Medford-Ashland Air Quality Maintenance Area, light duty vehicles up to 20 years old as well as heavy-duty vehicles must be submitted for emissions inspection.
26. Pennsylvania – Periodic emissions inspections are required for all motor vehicles with some exceptions.
27. Rhode Island – Emissions inspections are required biennially for all vehicles with some exceptions.
28. Tennessee – People who live in Davidson, Hamilton, Rutherford, Sumner, Williamson, and Wilson counties in Middle Tennessee and residents of Memphis in West Tennessee must have their vehicles pass an emissions inspection prior to registration renewal. Shelby County residents who live inside the city limits of Memphis also must have their vehicles inspected prior to title and registration.
29. Texas – Designated vehicles must pass an emissions inspection prior to registration. The emissions inspection is required annually with a safety inspection in Brazoria, Collin, Dallas, Denton, Ellis, El Paso, Fort Bend, Galveston, Harris, Johnson, Kaufman, Parker, Rockwall, Tarrant, Travis, and Williamson counties.
30. Utah – Diesel- and gas-powered cars and trucks manufactured in 1968 or later must have an annual emissions test. New vehicles, motorcycles, and vehicles with a model year of 1967 and older are exempt from this requirement. Certificates are required in Davis, Salt Lake, Utah, and Weber counties. Frequency of emissions testing may depend on the age of the vehicle.
31. Vermont – Adopted the California Low Emission Vehicle (LEV) Program, which requires dealerships to sell the cleanest cars available to residents.
32. Virginia – Vehicles that have a weight of 10,000 lbs or less that are registered in the Northern Virginia region must have emissions inspections done on a biennial basis at official emissions inspection stations. This does not apply to motorcycles, “clean fuel” vehicles, hybrid cars, antique vehicles, or vehicles 4 years old or less.
33. Washington – Vehicles that are five through 25 years old that are registered in parts of Clark, King, Pierce, Snohomish, and Spokane counties must pass an inspection test every two years. Additionally, vehicles with even-numbered model years must be inspected in even-numbered years, and vehicles with odd-numbered model years must be inspected in odd-numbered years. A certificate of acceptance is granted under a few different exceptions.
34. Wisconsin – In Kenosha, Milwaukee, Ozaukee, Racine, Sheboygan, Washington, and Waukesha counties, non-exempt vehicles that are subject to inspection must have the inspection completed at an inspection station not more than 90 days prior to renewal of annual registration. Emissions inspections are required beginning the 3rd year following the vehicle’s model year and every 2 years thereafter.
States that are not listed do not currently require emissions testing. For more specifics into model year and application exceptions, visit the Clean Air Act or DMV websites and search for your state.
With emissions regulations tightening nationwide and by state, now’s the time to get your truck or fleet in compliance. From engine to tailpipe, your exhaust and emissions system needs to be at peak performance to not only keep harmful emissions out of the air but also to keep dangerous fumes from entering the cab.
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