Displaying your USDOT number and other regulation numbers that are applicable to you are very important when engaging in business. The FMCSA has the authority to fine and sanction unsafe interstate truck and bus companies. USDOT & other regulation numbers are used to identify potentially unsafe motor carriers when analyzing crash sites. The identification numbers (found on each side of the power unit, assigned by the USDOT & By The State) is a key element in the FMCSA database for both carrier safety and the regulatory process. In the image below, you can see that the semi-truck is destroyed, but the USDOT number is clearly visible for authorities to run an investigation and issue fines.