A DOT Number is a unique identification number issued by the Federal Motor Carrier Safety Administration (FMCSA) to track a company’s safety records, inspections, crash investigations, and compliance reviews. It serves as a digital fingerprint for commercial motor carriers operating in the United States and is required for companies involved in transporting goods or passengers across state lines. The DOT Number allows authorities to monitor a carrier’s safety performance and regulatory compliance.

You need a USDOT Number if you operate a commercial vehicle that transports passengers or hauls cargo in interstate commerce (across state lines), or if your vehicle meets certain weight thresholds or carries hazardous materials, even within a single state. Most states also require a USDOT Number for intrastate carriers using vehicles over 10,000 pounds. If you are starting a trucking business, passenger transport service, or freight operation, obtaining a DOT Number is often your first required step toward compliance.

An MC Number, also known as Operating Authority, is an additional registration issued by the FMCSA that authorizes for-hire carriers to transport regulated commodities across state lines for compensation. While the DOT Number identifies your company for safety tracking purposes, the MC Number determines the type of operation you are allowed to conduct — such as hauling freight for hire. Most carriers who transport goods across state lines and get paid for it must obtain both a DOT and MC Number to legally operate.