Now you need Operating Authority. To haul across state lines, you need Interstate Operating Authority - a "Motor Carrier (MC) Number" from FMCSA.Complete Trucking Authority Packages. Our complete authority packages are designed to give you every filing actually required to get you on the road. FMCSA operating authority is often identified as an "MC," "FF," or "MX" number, depending on the type of authority that is granted. When you have filed all of the paperwork necessary to operate a trucking company, the FMCSA will send you a letter of authority. Get your own trucking authority in Texas with our comprehensive trucking authority packages and expert services. At DOT Operating Authority we are happy to help with any filing assistance you may need! A forward-thinking leader delivering mobility, enabling economic opportunity, and enhancing quality of life for all Texans. South San Antonio ISD.