Abbreviation: DOT Number
USDOT Number
A unique identifier assigned by FMCSA to carriers and certain other entities subject to its safety regulations. Required for interstate commercial motor vehicle operations above FMCSA thresholds.
Carriers with a USDOT number must comply with FMCSA regulations, including DQ file requirements, drug/alcohol testing, and Clearinghouse obligations.
Who needs a USDOT number
A USDOT number is required for: carriers operating CMVs in interstate commerce with a GVWR of 10,001 lbs or more; carriers transporting placarded hazardous materials in interstate commerce; carriers transporting 9 or more passengers for compensation; and carriers transporting 15 or more passengers not for compensation. Some states require a USDOT number for intrastate operations — check your state's requirements.
Keeping it current
Carriers must keep their USDOT registration current by filing the MCS-150 biennial update every two years (in the month of their original registration). The biennial update keeps the USDOT number active and updates carrier information. Operating with a delinquent USDOT number can result in fines and enforcement action. Use FMCSA's SAFER system to check your current status.
Last updated: June 4, 2026
When this definition matters
This term usually matters when a driver, owner-operator, or small carrier is deciding whether a federal rule applies, preparing a compliance file, or checking a state CDL step. Use this definition as a starting point, then confirm the controlling requirement in the official source listed below before making a licensing, hiring, dispatch, or recordkeeping decision.
The related terms above are included because they often appear in the same compliance workflow. Reviewing them together can prevent common mix-ups, such as treating a state licensing step as a federal carrier obligation or confusing a driver record with a separate employer record.