Reference Source

Missouri

For Missouri, counties where testing is required is St. Louis City St. Louis County St. Charles County Jefferson County; vehicles covered / exempt is Gas-powered vehicles 1996 and newer or diesel powered vehicles 1997 and newer; program / authority is Gateway VIP, verified against its source on 2026-08-19.

State
Missouri our reading
Counties where testing is required
St. Louis City St. Louis County St. Charles County Jefferson County verified
Vehicles covered / exempt
Gas-powered vehicles 1996 and newer or diesel powered vehicles 1997 and newer verified
Program / authority
Gateway VIP verified
How often
Odd vehicle model years test in odd years. Even vehicle model years test in even year. per gatewayvip.mo.gov
Sourcegatewayvip.mo.gov
Verified
Review by
DatasetVehicle emissions testing: which counties require it, in which states

Values marked our reading are our classification of what the source says — the source does not print them in those words. The quote below is the evidence for each one; judge it yourself.

What the source says

Gas-powered vehicles 1996 and newer or diesel powered vehicles 1997 and newer 8,500 pounds or less. Registered in the following areas: <https://gatewayvip.mo.gov/locate-a-gvip-station-near-you/> Locate a GVIP Station near you St. Louis City St. Louis County St. Charles County Jefferson County When do I get a test?

gatewayvip.mo.gov, retrieved 2026-08-19

What gatewayvip.mo.gov says

Odd vehicle model years test in odd years. Even vehicle model years test in even year.

gatewayvip.mo.gov, retrieved 2026-08-19

Source

Last verified against source: . Due for re-check by . This page as Markdown · OKF bundle · full dataset as JSON.