Smog Laws by State

Most states require motorists to have the emission levels of their vehicles tested to ensure that pollution levels stay below a predetermined threshold. These statutes, often referred to as "smog laws," typically have exceptions for antique cars or those that are relatively new. In states that have such requirements, motorists must show proof (or have it sent in by the mechanic) that their vehicle is compliant with the law before a license and registration may be renewed.  

Smog Testing: Overview

Every state has its own process and standards for what is considered an acceptable level of pollution from a vehicle, but sometimes these regulations pertain only to dense urban areas. For instance, Missouri's emissions standards and inspection requirements pertain only to those living in the St. Louis Metropolitan Area. Also, certain vehicles are usually exempt. Antique vehicles are one example, since they were engineered before it was possible to build cleaner and more efficient engines. Newer cars also are typically exempt, since manufactures are required to meet current standards anyway. 

Emissions from the transportation sector represented 26 percent of all greenhouse gas emissions in 2014, according to the U.S. Environmental Protection Agency (EPA), making it the second-highest emitter of such pollution by industry sector. Electricity generation came in first on the list. But while cars have gotten much more efficient and clean-burning than ever before, the ever-increasing number of vehicles on the road has kept these levels high.

State Smog Laws

Links to state emissions testing regulations are listed below:

None

None

Vehicle Emissions

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Smog Information

General Emissions Inspection Requirements and Information

Connecticut Emissions Program

Vehicle Services: Exhaust Emission Inspection

District of Columbia

D.C. DMV Exhaust Emissions Testing

Georgia Vehicle Emissions Inspection and Maintenance Program

None

Idaho Vehicle Emissions Testing

Vehicle Emissions Testing Program

Vehicle Emissions Testing Program

None

Motor Vehicle Inspection and Maintenance Program

Vehicle Emissions Inspection Program

Massachusetts Vehicle Check

None

None

None

Gateway Vehicle Inspection Program (St. Louis metro area)

None

Understanding Inspections and the Emissions Test

Emission Testing

New York State Vehicle Safety/Emissions Inspection Program

Vehicle Emissions and Safety Inspection

None

Ohio E-Check Program

None

Department of Environmental Quality Emissions Testing

Emissions Inspection Program

Emissions and Safety Testing

None

None

Vehicle Inspection

Emission Inspections

Emissions Inspections

Washington State Vehicle Emission Check Program

None

 

Need Legal Advice for a Smog-Related Offense? Ask a Lawyer

Smog regulations are fairly straight-forward and typically don't require legal action. However, every situation is different and you may find yourself in need of expert advice. Contact a traffic law attorney in your area for more information.