Fast Trucking ComplianceCompliance FAQ
What is the difference between an MC number and an MX number?
An MC number is FMCSA operating authority issued to U.S.-domiciled motor carriers and brokers under 49 USC §13902. An MX number is the same kind of operating authority but issued to Mexican-domiciled carriers operating in the United States under the cross-border long-haul program implemented by 49 CFR §365.501 and the NAFTA / USMCA framework. Both are docket numbers in the same FMCSA registry - they sit side-by-side on SAFER. The differences are which border the carrier crosses to enter U.S. commerce and which insurance and equipment-inspection rules apply. Mexican MX carriers must show CVSA-decaled equipment, drug-and-alcohol testing under 49 CFR Part 382 with a U.S.-recognized MRO, and proof of border-crossing insurance written by an admitted U.S. insurer. Canadian carriers usually run on a regular MC docket because Canadian provinces have a reciprocal agreement with FMCSA.
Why it matters
U.S. shippers using an MX-numbered carrier sometimes get tripped up because their TMS only validates MC dockets. The fix is to point the TMS at the SAFER MX lookup or to store the docket field as a generic FMCSA-operating-authority string. The compliance requirements on the U.S. side - BIPD insurance under 49 CFR Part 387, BOC-3 process agents in every state of intended operation, UCR registration, MCS-150 biennial updates - apply to MX carriers identically.
FMCSA operates a separate Mexican border-crossing safety pilot program for long-haul MX-AA dockets that allow a Mexican carrier to operate beyond the 25-mile border zone. That program has additional pre-authorization safety audit requirements. Most freight originating in Mexico is drayed across the border by an MX-B (border zone) carrier and reloaded onto a U.S. MC carrier in a transload yard.
For practical purposes a U.S. broker books MC dockets, period.