The Federal Motor Carrier Safety Administration requires that motor carriers apply for a U.S. DOT number, using the
Motor Carrier Identification Report (MCS-150), shown on Page 9.6. This form must also be used to update the motor carrier’s information every two years, unless the carrier uses the following website for such updates: http://www.usdotnumberregistration.com. The last two digits of a carrier’s DOT number define when the update is due; the last digit represents the month (0 = October) and the 2nd to last digit determines the year due (odd or even).
Example: If the carrier’s U.S. DOT number ends in 38, the updated MCS-150 is due in August (8) every two years ending in an odd number (i.e., 2001, 2003, etc.).