Emissions Testing in Missouri

Testing Requirements

Current Testing Requirements in Missouri

Missouri operates the Gateway Vehicle Inspection Program (GVIP) for vehicles registered in the St. Louis nonattainment area. The program began October 1, 2007, replacing the former centralized Gateway Clean Air Program. The Missouri Department of Natural Resources and the Missouri State Highway Patrol jointly administer GVIP. Testing is performed at licensed private inspection stations in the covered area. For applicable vehicles, the test is an OBD-II diagnostic scan that checks emissions readiness monitors and stored diagnostic trouble codes. A separate biennial safety inspection is required for vehicles 10 model years old or older or with more than 150,000 miles on the odometer, and applies statewide. The emissions test and safety inspection are performed at the same licensed stations and can be completed during a single visit.

Who Needs an Emissions Test

Gasoline-powered vehicles model year 1996 and newer and diesel-powered vehicles model year 1997 and newer with a gross vehicle weight rating of 8,500 pounds or less registered in the covered area must pass an emissions test. An emissions test is also required at any title change for eligible vehicles in the covered area. The seller of a vehicle in the covered area must provide the buyer with a passing emissions certificate or waiver. New vehicles are exempt for the first four model years if untitled or unregistered during that period and driven less than 40,000 miles. Vehicles model year 1995 and older (gasoline) and 1996 and older (diesel) are exempt. Motorcycles, mopeds, historic vehicles, electric vehicles, vehicles over 8,500 pounds GVWR, and vehicles driven less than 12,000 miles between biennial safety inspections are also exempt.

How Often Tests Are Required

Emissions testing is biennial, following a model year odd/even cycle. Even model year vehicles are tested in even calendar years. Odd model year vehicles are tested in odd calendar years. An emissions test is also required at any title transfer for eligible vehicles. In some cases, a vehicle sold between biennial cycles may need testing in two consecutive years. The Missouri Department of Revenue mails registration renewal paperwork 60 days before plate expiration, which indicates whether an emissions test and safety inspection are due. The emissions certificate is valid for 60 days for registration purposes.

Where Emissions Testing Is Required

Emissions testing is required in four jurisdictions: St. Louis City, St. Louis County, St. Charles County, and Jefferson County. Vehicles registered anywhere else in Missouri are not required to pass an emissions test. The rest of the state, including Kansas City, Springfield, Columbia, and all other counties, requires only the biennial safety inspection (for eligible vehicles) without an emissions component.

What Happens During the Test

A technician connects to the vehicle's OBD-II port and checks for stored emissions-related diagnostic trouble codes, readiness monitor status, and the malfunction indicator lamp. A lit check engine light causes automatic failure. If readiness monitors have not completed their self-checks, the vehicle may be returned as "not ready" and the owner must drive the vehicle through normal conditions to allow the monitors to reset. A visual inspection of emissions control components may also be performed. The emissions test typically takes 10 to 15 minutes. If the vehicle is also due for a safety inspection, the two tests are performed during the same visit.

Areas in Missouri That Require Emissions Testing

Within the covered area, cities and communities where emissions testing is required include St. Louis, University City, Clayton, Ferguson, Florissant, Hazelwood, Bridgeton, Ballwin, Chesterfield, Creve Coeur, Kirkwood, Webster Groves, O'Fallon, St. Charles, St. Peters, Wentzville, Festus, Arnold, Herculaneum, Crystal City, Hillsboro, and Barnhart. Cities outside the four covered jurisdictions do not require emissions testing. Kansas City, Springfield, Columbia, Independence, Lee's Summit, St. Joseph, Blue Springs, Joplin, Jefferson City, Cape Girardeau, and all other Missouri cities outside the GVIP area need only the statewide safety inspection when applicable.

How the Emissions Test Works in Missouri

Drivers take their vehicle to any licensed GVIP inspection station in the covered area. These are private auto shops and service stations authorized by the state. No appointment is needed at most stations. Bring your vehicle registration and renewal notice. The emissions test fee is set by individual stations and is not state-regulated, though fees are typically in the range of $20 to $35. The safety inspection fee is separate. If the vehicle passes, it receives an emissions inspection compliance certificate valid for 60 days. Registration renewal requires a valid certificate. If the vehicle fails, one free retest is available if completed within 20 days of the initial failure. Repairs should be performed by a Missouri Recognized Repair Technician (MRRT) for waiver eligibility. A cost-based waiver may be available if the vehicle fails after qualifying emissions repairs totaling at least $450 (by an MRRT or non-MRRT), or $400 if the owner performed the repairs. A financial hardship waiver is available for vehicle owners dependent on government assistance who spend at least $200 on repairs. Waiver applications are submitted to the Department of Natural Resources GVIP office at 314-416-2115.