Missouri has adopted 390.21 of the Federal Motor Carrier Safety Regulations (FMCSRs).
Section 390.21 applies to an intrastate vehicle with a gross vehicle weight rating or gross combination weight rating, or gross vehicle weight or gross combination weight of 26,001 pounds or more, or a vehicle of any size transporting a placardable amount of hazardous materials.
All commercial vehicles operating solely in intrastate transportation must display their USDOT number followed by “MO” on all vehicles.
Example: US DOT 123456 MO