Pursuant to 49 U.S.C. § 390.19T, motor carriers and intermodal equipment providers must file an MCS-150 update every two years, by the end of a particular month based on your USDOT number. You can learn more about this requirement and update your MCS-150 through this page at the FMCSA.
It is important that you provide total mileage operated during the most recently completed calendar year to keep your filing current, and to update the number of power units you operate. Average power units is used to calculate certain CSA scores, and to determine which level UCR fee you must pay each year.