Missouri safety and emissions inspection requirements split along two lines: age and mileage decide the safety inspection, and the county of registration decides the emissions test. Every vehicle registered in the state needs a biennial safety inspection unless it falls into an exempt category, and vehicles registered in St. Louis City, St. Louis County, St. Charles County, or Jefferson County also need an emissions inspection.1Missouri Department of Revenue. Motor Vehicle – Additional Help Resources Whether you need one, both, or neither comes down to how old the vehicle is, how many miles are on it, and where you live.
When a Safety Inspection Is Required
Missouri law requires the owner of every registered motor vehicle to get a biennial safety inspection unless the vehicle is exempt.2Missouri Revisor of Statutes. Missouri Code 307.350 – Biennial Inspection of Motor Vehicles Required An inspection is also required when a vehicle is sold or transferred, and when a new resident registers a vehicle in Missouri for the first time.
The main exemption covers newer, lower-mileage cars: vehicles within ten model years of manufacture that have fewer than 150,000 miles on the odometer don’t need the safety inspection.1Missouri Department of Revenue. Motor Vehicle – Additional Help Resources Both conditions have to be true. Cross either threshold and the inspection kicks in.
Other exempt vehicles include:
- All trailers.
- Vehicles with historic plates registered under Section 301.131.
- Heavy vehicles registered for 26,000 pounds or above and registered for less than 12 months.1Missouri Department of Revenue. Motor Vehicle – Additional Help Resources
- Interstate commerce vehicles registered with the Missouri Department of Transportation.
- Low-speed vehicles as defined in Section 304.029.
- Vehicles sold for junk, salvage, or rebuilding, and dealer-to-dealer sales.
One exception that catches owners off guard: the ten-year, 150,000-mile exemption does not apply to prior salvage vehicles that have just been rebuilt. Those need an inspection regardless of age or mileage.2Missouri Revisor of Statutes. Missouri Code 307.350 – Biennial Inspection of Motor Vehicles Required
When an Emissions Inspection Is Required
Emissions testing applies only in four jurisdictions: St. Louis City, St. Louis County, St. Charles County, and Jefferson County.1Missouri Department of Revenue. Motor Vehicle – Additional Help Resources If your vehicle is registered anywhere else in the state, you don’t need one. The requirement exists because those areas fall under federal Clean Air Act mandates for regions with elevated ozone or carbon monoxide levels.3eCFR. 40 CFR Part 51 Subpart S – Inspection/Maintenance Program Requirements
Within those four areas, the emissions test applies to gasoline-powered vehicles from model year 1996 and newer, and diesel vehicles from model year 1997 and newer, with a gross vehicle weight rating of 8,500 pounds or less.4Missouri Revisor of Statutes. Missouri Code 643.315 – Motor Vehicles Subject to Program
Exemptions from the emissions requirement, even within those four counties, include:
- Vehicles over 8,500 pounds GVWR.
- Gasoline vehicles manufactured before 1996 and diesel vehicles manufactured before 1997.1Missouri Department of Revenue. Motor Vehicle – Additional Help Resources
- New vehicles during their model year and the following year, as long as the odometer reads under 6,000 miles at the time of sale.
- Motorcycles and motortricycles.4Missouri Revisor of Statutes. Missouri Code 643.315 – Motor Vehicles Subject to Program
- Vehicles powered exclusively by electricity or hydrogen.
Those pre-1996 and pre-1997 cutoffs are fixed model years, not a rolling age. A 1995 gasoline car stays exempt forever, and a 2000 gasoline car will never age out of the requirement.
How the Biennial Cycle Decides Your Year
Missouri doesn’t run inspections on a rolling two-year clock from your last test. Even-numbered model year vehicles get inspected in even-numbered calendar years, and odd-numbered model year vehicles get inspected in odd-numbered calendar years.2Missouri Revisor of Statutes. Missouri Code 307.350 – Biennial Inspection of Motor Vehicles Required If your model year’s parity doesn’t match the calendar year, you’re not due. The registration renewal notice from the Department of Revenue will tell you whether an inspection is required for your upcoming renewal.
Fees and What Happens If You Fail
The maximum fee for a safety inspection is $12, and the maximum for an emissions inspection is $24.5Missouri State Highway Patrol. Official Safety Inspection – FAQs Stations may charge less but cannot charge more.
If you fail either inspection, you get one free re-inspection at the same station within 20 business days after repairs.6Gateway VIP. Vehicle Failed Emissions Test Change stations or miss the window, and you pay full price again.
For emissions failures specifically, the Gateway Vehicle Inspection Program offers a cost-based waiver. If you’ve failed an emissions test, spent a qualifying amount on emissions-related repairs, and the vehicle still won’t pass on retest, you can apply for a one-cycle waiver that lets you register the vehicle anyway.6Gateway VIP. Vehicle Failed Emissions Test One practical consequence: if your check engine light is on, don’t repair first and test second. The waiver only credits repairs made after a documented failure, so paying for work before your first test means those costs can’t help you qualify.7Gateway VIP. Malfunction Indicator Lamp (MIL) aka Check Engine or Service Engine Soon Light The waiver lasts one inspection cycle, so the underlying problem still has to be fixed before next time.
Timing the Inspection for Registration
A passing safety inspection produces a Certificate of Inspection and Approval, which you need to register your vehicle or renew registration with the Department of Revenue. The certificate is valid for 60 days from the inspection date. One exception: if you bought the vehicle from a Missouri dealer and it was inspected within 60 days before the purchase, that certificate stays valid for 90 days from the inspection date.2Missouri Revisor of Statutes. Missouri Code 307.350 – Biennial Inspection of Motor Vehicles Required Emissions results are also valid for 60 days for registration purposes.1Missouri Department of Revenue. Motor Vehicle – Additional Help Resources
Don’t test too early. If registration doesn’t expire for three months, wait. An inspection older than 60 days when you apply won’t count.
Penalties for Driving Without a Valid Inspection
Failing to display a certificate of vehicle inspection or approval is a citable traffic offense under Missouri law.2Missouri Revisor of Statutes. Missouri Code 307.350 – Biennial Inspection of Motor Vehicles Required Violations of the emissions inspection requirements are a class C misdemeanor, which can carry a fine and up to 15 days in jail.8Missouri Revisor of Statutes. Missouri Code 307.365 – Violations The more immediate problem is that you can’t register or renew the vehicle until a passing inspection is on file.