A USDOT number is required if a vehicle is transporting material considered hazardous by the Secretary of Transportation and in a large quantity. Other requirements pertain to gross vehicle weight, interstate commerce and whether the vehicle carries passengers for compensation.
A gross vehicle weight of 10,001 pounds or more requires a USDOT registration number. If the vehicle is used to transport eight or more passengers, including the driver, for compensation, a registration number is required. Vehicles carrying 15 or more passengers but not for compensation are still required to obtain a registration number.
USDOT registration numbers are required when vehicles meet one or more of the criteria above and are used for interstate commerce. Interstate commerce is described as trade, traffic or transportation between two or more states. This includes territories outside the United States. The definition also includes trade, traffic or transportation within a state while passing through another state or two places in a state that either originate or terminate outside the state or the United States.
A USDOT number is a unique identifier that is used to monitor and collect a company's safety information acquired during an audit, inspection or crash investigation. USDOT numbers are administered by the Federal Motor Carrier Safety Administration.