# Missouri — Vehicle emissions testing: which counties require it, in which states

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, not quoted from the source)_
- **Counties where testing is required:** St. Louis City St. Louis County St. Charles County Jefferson County _(verified: appears in the quote below)_
- **Vehicles covered / exempt:** Gas-powered vehicles 1996 and newer or diesel powered vehicles 1997 and newer _(verified: appears in the quote below)_
- **Program / authority:** Gateway VIP _(verified: appears in the quote below)_
- **How often:** Odd vehicle model years test in odd years. Even vehicle model years test in even year. _(per gatewayvip.mo.gov, not stated by the source above)_

## 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?

## What gatewayvip.mo.gov says

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

Source: https://gatewayvip.mo.gov/need-test/

## Source

- https://gatewayvip.mo.gov/need-test/

Last verified: 2026-08-19. Review by: 2027-08-19.
Part of [Vehicle emissions testing: which counties require it, in which states](https://referencesource.org/vehicle-emissions-testing-by-state/).