{"state":"MO","state_name":"Missouri","county":"st-charles","county_name":"St. Charles County","testing_required":true,"gas_testing_required":true,"gas_model_year_min":1996,"diesel_testing_required":true,"diesel_model_year_min":1997,"diesel_vehicle_max_gvwr_lbs":8500,"test_fee_cents":0,"exemptions":["motor vehicles and RVs with a manufacturer's gross vehicle weight rating over 8,500 pounds","new motor vehicles on an MSO during the 4-year period following the model year when the odometer is under 40,000 miles and Missouri grants the waiver","1995 and older gasoline vehicles and 1996 and older diesel vehicles","motor vehicles driven fewer than 12,000 miles between biennial safety inspections when the mileage waiver is approved","vehicles registered in an affected county but based and operated outside the testing area for at least 24 months when the out-of-area waiver is approved"],"stations":[],"station_details":[],"source_url":"https://dor.mo.gov/motor-vehicle/additional-help-resources.html","source_updated_at":"2026-04-23 07:18:55","coverage_status":"partial","confidence_note":"Core Missouri emissions coverage is source-backed, but Missouri applies parity-year exemptions and county participation through the Gateway Vehicle Inspection Program while live station coverage remains delegated to the official finder.","stations_scope":"official_finder","stations_scope_label":"Official inspection station finder","stations_note":"Missouri publishes St. Charles County emissions coverage through the Gateway Vehicle Inspection Program, but live station availability is delegated to the official station finder.","station_locator_url":"https://gatewayvip.mo.gov/locate-a-gvip-station-near-you/","help_cta":{"kind":"official_service","headline":"Open the official St. Charles County testing workflow","body":"PlateHarbor mapped the main county testing rules and finder coverage. Use the official source or locator before you schedule a test or travel to a station.","label":"Open official station finder","href":"https://gatewayvip.mo.gov/locate-a-gvip-station-near-you/","placement":"after-official-links","disclosure":"Official station finder","tracking_key":"official-emissions-missouri-st-charles"}}