Do You Need Both Safety and Emissions in Missouri?

Missouri safety and emissions inspection requirements depend on three things: how old your vehicle is, how many miles it has, and where it’s registered. Most vehicles in the state need a safety inspection every two years once they pass a certain age or mileage threshold, and vehicles registered in St. Louis City, St. Louis County, St. Charles County, or Jefferson County also need an emissions inspection.¹ Everywhere else in Missouri, only the safety inspection applies.

When You Need a Safety Inspection

Missouri law requires the owner of every registered motor vehicle to get a biennial safety inspection unless the vehicle is exempt.² An inspection is also required whenever a vehicle is sold or transferred, and when a new resident registers a vehicle in Missouri for the first time.

The most common exemption is for newer, lower-mileage vehicles: if your car is within ten model years of the current year and has fewer than 150,000 miles on the odometer, you don’t need a safety inspection.¹ Cross either threshold and the inspection kicks in.

Other exempt categories 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.¹
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 catch trips people up. 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.²

When You Need an Emissions Inspection

Emissions inspections are only required for vehicles registered in four jurisdictions: St. Louis City, St. Louis County, St. Charles County, and Jefferson County.¹ Registered anywhere else in Missouri, you don’t need one. The requirement exists because these areas fall under federal Clean Air Act mandates for regions with elevated ozone or carbon monoxide levels.³

Within those four areas, the emissions test applies to gasoline 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.⁴

Even inside those counties, some vehicles are exempt:

Vehicles over 8,500 pounds GVWR.
Gasoline vehicles manufactured before 1996 and diesel vehicles manufactured before 1997.¹
New vehicles during their model year and the following year, provided the odometer reads under 6,000 miles at the time of sale.
Motorcycles and motortricycles.⁴
Vehicles powered exclusively by electricity or hydrogen.

The pre-1996 gasoline and pre-1997 diesel cutoffs are fixed model years, not a rolling age threshold. A 1995 gasoline vehicle will always be exempt. A 2000 gasoline vehicle will never age out.

How the Two-Year Cycle Works

Missouri doesn’t run inspections on a rolling schedule 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.² If your model year doesn’t match the current calendar year’s parity, you’re not due this year. Your registration renewal notice from the Department of Revenue will tell you whether an inspection is needed. Emissions inspections follow the same even/odd cycle.

Fees, Re-Inspections, and Emissions Waivers

The maximum fee for a safety inspection is $12. For an emissions inspection, the maximum is $24.⁵ Stations may charge less but not more.

If your vehicle fails either inspection, you get one free re-inspection at the same station within 20 business days after making repairs.⁶ Go to a different station or miss the 20-day window, and you’ll pay the full fee again.

For emissions failures, 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.⁶ The waiver only lasts one inspection cycle, so the underlying problem still needs to be resolved before the next round.

A Note on the Check Engine Light

If your check engine light is on and you’re heading in for an emissions test, don’t rush to fix it first. The Gateway Vehicle Inspection Program recommends testing with the light on before making repairs.⁷ The reason is practical: if your vehicle fails, you may qualify for the cost-based waiver, but only repairs done after a documented failure count toward it. Money spent before the first test doesn’t help.

Using the Certificate to Register

A passing safety inspection produces a Certificate of Inspection and Approval, which you need to register or renew your vehicle with the Department of Revenue. The certificate is valid for 60 days from the inspection date.² Emissions results are also valid for 60 days for registration purposes.¹

There’s one exception. If you bought the vehicle from a Missouri dealer and it was inspected within 60 days before the purchase, the certificate stays valid for 90 days from the inspection date.²

Don’t inspect too early. An inspection done more than 60 days before you apply for registration won’t count, so wait until closer to your renewal deadline.

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.² Violations of the state’s emissions inspection requirements are a class C misdemeanor, which can carry a fine and up to 15 days in jail.⁸ In practice, most drivers end up paying a fine and court costs over $100. The bigger problem is that you can’t register or renew the vehicle without a passing inspection on file.

Active-Duty Military Stationed Out of State

If you’re on active duty and your vehicle is out of state at renewal time, Missouri allows another person to sign a General Affidavit (Form 768) on your behalf confirming the vehicle is out of state and will be inspected within 10 days of returning. Service members can also renew an expired registration up to 60 days after discharge from the U.S. Armed Forces without a late penalty.⁹

Finding a Station

Safety inspections can only be performed at state-authorized inspection stations, which display a large yellow sign with black lettering. You can search by city or zip code on the Missouri State Highway Patrol’s station locator.¹⁰ For emissions inspections in the St. Louis area, use a station authorized through the Gateway Vehicle Inspection Program.

1
Missouri Department of Revenue. Motor Vehicle – Additional Help Resources
2
Missouri Revisor of Statutes. Missouri Code 307.350 – Biennial Inspection of Motor Vehicles Required
3
eCFR. 40 CFR Part 51 Subpart S – Inspection/Maintenance Program Requirements
4
Missouri Revisor of Statutes. Missouri Code 643.315 – Motor Vehicles Subject to Program
5
Missouri State Highway Patrol. Official Safety Inspection – FAQs
6
Gateway VIP. Vehicle Failed Emissions Test
7
Gateway VIP. Malfunction Indicator Lamp (MIL) aka Check Engine or Service Engine Soon Light
8
Missouri Revisor of Statutes. Missouri Code 307.365 – Violations
9
MyAirForceBenefits. Missouri Military and Veterans Benefits
10
Missouri State Highway Patrol. MVI Stations Search Locations