DOT Number (USDOT Number)
A unique identifier assigned by the U.S. Department of Transportation to every motor carrier, broker, and freight forwarder in interstate commerce. The DOT number is the primary key for looking up safety records, insurance, and authority in FMCSA databases. CarrierOk indexes over 4.2 million DOT numbers.
Definition
The USDOT number is a unique identifier assigned by the U.S. Department of Transportation to every entity required to register for interstate commercial vehicle operations. This includes motor carriers, brokers, freight forwarders, and certain intrastate carriers depending on state requirements. Unlike the MC number (which is specific to for-hire carriers and brokers), the DOT number is required for all commercial vehicle operators engaged in interstate commerce, including private carriers hauling their own goods. The DOT number serves as the primary key across all FMCSA databases — SAFER, SMS, MCMIS, and L&I filings all reference carriers by DOT number. It must be displayed on both sides of every commercial vehicle the carrier operates. DOT numbers are assigned sequentially, so the number itself provides a rough indicator of when the carrier registered — higher numbers indicate more recent registration. CarrierOk indexes over 4.2 million DOT numbers and supports lookup by DOT number, MC number, legal name, or DBA. The dot_age field calculates the time since initial registration, which is a key input to new-entrant risk assessment.
Why It Matters
For Underwriters
The DOT number is your primary lookup key for every carrier evaluation — all safety scores, inspection history, insurance filings, and authority data are keyed to this number.
For Brokers
Always collect and verify the DOT number before onboarding a carrier — it's the only reliable way to confirm you're working with the entity you think you are, not a spoofed or fictional carrier.
For Developers
DOT number is the primary key parameter for the CarrierOk API — all profile lookups use dot_number, and the field dot_age provides a quick proxy for carrier maturity without additional date math.
In the API
/v2/profileRelated Fields
dot_numberdot_agelegal_namedocket_numberdocket_prefixeinFrequently Asked Questions
What is a DOT number for a trucking company?
A DOT number (USDOT number) is a unique identifier assigned by the U.S. Department of Transportation to every motor carrier, broker, and freight forwarder operating in interstate commerce. It is the primary key used to look up a carrier's safety record, insurance status, and operating authority across all FMCSA databases. Every commercial vehicle must display the DOT number on both sides.
What is the difference between a DOT number and an MC number?
A DOT number is required for all interstate commercial vehicle operators, including private carriers hauling their own goods. An MC number is a docket number assigned only to for-hire carriers and brokers when they apply for operating authority. A single entity often has both — the DOT number identifies the entity, while the MC number identifies its authority to haul freight for hire.
How do I look up a carrier by DOT number?
You can look up carriers on FMCSA's SAFER website for basic information, or use the CarrierOk API for comprehensive data including all 7 BASIC percentiles, ISS scores, insurance details, and risk signals. CarrierOk's /v2/profile endpoint accepts a DOT number and returns the complete carrier profile in a single API call.
Related Terms
MC Number (Motor Carrier Number)
A docket number assigned by FMCSA to for-hire carriers and brokers when they register for operating authority. Unlike DOT numbers (required for all interstate CMV operators), MC numbers are specific to for-hire and brokerage operations. CarrierOk supports lookup by MC number, DOT number, or legal name.
Operating Authority
FMCSA-granted permission for a motor carrier, broker, or freight forwarder to operate in interstate commerce. Authority types include common (general for-hire), contract (specific shippers), and broker. CarrierOk tracks authority status changes same-day and alerts subscribers when a carrier's authority lapses or is revoked.
FMCSA (Federal Motor Carrier Safety Administration)
The federal agency within the U.S. Department of Transportation that regulates the trucking and bus industries. FMCSA issues operating authority, sets safety standards, and maintains the databases — SAFER, SMS, MCMIS, L&I — that CarrierOk indexes four times daily to power its carrier intelligence platform.
SAFER (Safety and Fitness Electronic Records)
FMCSA's public-facing website for looking up motor carrier safety information, including operating status, authority, and limited inspection data. SAFER does not compute BASIC percentiles, does not serve ISS scores, and updates less frequently. CarrierOk replaces manual SAFER lookups with a comprehensive, API-accessible carrier intelligence platform.