Glossary
MC number
An MC number (motor carrier number, also called a docket number) is the identifier FMCSA historically assigned to a company's grant of operating authority: the legal permission to transport regulated freight for hire in interstate commerce. One company, one USDOT number; but a company could be associated with one or more docket numbers as it acquired different authorities.
Why it still matters
Load boards, rate confirmations, and broker paperwork still lean on MC numbers, so it's often the number you have in hand. It works fine as a lookup key, with one caveat: it's the older system. FMCSA has been consolidating registration around the USDOT number, and new filings increasingly reference USDOT directly.
The practical rule
Use whichever number you have; anchor your records on the USDOT number. fleetfax accepts both and resolves an MC number to its USDOT record automatically, so a search by either lands on the same carrier report.
One number, one company
If the company quoting you a load gives an MC number that resolves to a different legal name than the one on the rate con, that's worth resolving before anything else. Identity mismatches are where the worst freight fraud lives, and the federal record is the arbiter of who an MC number actually belongs to.
Related terms
USDOT number
The federal registration number every interstate carrier must hold. The primary key of the federal carrier record.
Operating authority
FMCSA's grant of legal permission to operate for hire: common, contract, or broker. Active, inactive, pending, revoked, and the gaps in between.
fleetfax reads public FMCSA data and is not affiliated with FMCSA or the U.S. Department of Transportation. This page explains terminology; it is not legal advice.