Why Do I Need a DOT Number?

by Stephanie Ellen - Updated September 26, 2017
Department of Transportation numbers are assigned to trucks.

The U.S. Department of Transportation Number is unique and assigned to each carrier. The department uses the number when monitoring a company’s safety record, as well as during audits, crash investigations and compliance reviews. You may need a USDOT number if you carry cargo or passengers in the U.S.


Any commercial vehicle that transports passengers must have a federal Department of Transportation (USDOT) number. Passenger vehicles include buses, vans, limousines and taxicabs. If you are a cargo carrier who will ever transport cargo across state lines, you must obtain a number. The Department of Transportation does not require you to obtain a number if you carry cargo locally, without going to another state.

Hazardous Materials

If you transport hazardous materials that require a safety permit, you must also register for a number. Hazardous materials include flammable gases (like methane and propane), flammable liquids (paints and gasoline), flammable solids (propellants and phosphorus), explosives (fireworks and dynamite), corrosives (acids and solvents), toxic gases and radioactive materials.

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Reasons for Numbers

DOT numbers are used to improve safety on U.S. highways. Any traffic citations, safety violations, or accidents are tracked using the DOT number. The Department of Transportation collects the data to establish safety ratings. This information can be shared with state regulatory bodies that perform compliance review's on businesses that are at a high risk for safety issues. If a company fails the compliance review the DOT number will be canceled and all vehicles associated with the number will have their registrations canceled.


New registrants for the DOT number are required to enter into an 18-month Federal Motor Carrier Safety Administration New Entrant Safety Assurance Program. The safety program ensures that applicants adhere to stringent safety requirements before being given a permanent number. In addition, company drivers must have a valid commercial driver’s license and be certified as medically fit to operate a vehicle.

State Requirements

These states require every trucker to have a DOT number before entering the state: Alabama, Alaska, Arizona, Colorado, Florida, Georgia, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Michigan, Minnesota, Missouri, Montana, New York, Ohio, Oklahoma, Oregon, South Carolina, Tennessee, Texas, Utah, Washington, West Virginia, Wisconsin and Wyoming.

About the Author

Stephanie Ellen teaches mathematics and statistics at the university and college level. She coauthored a statistics textbook published by Houghton-Mifflin. She has been writing professionally since 2008. Ellen holds a Bachelor of Science in health science from State University New York, a master's degree in math education from Jacksonville University and a Master of Arts in creative writing from National University.

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