(2) No motor carrier or intermodal equipment provider shall require or permit any person to operate nor shall any person operate any motor vehicle or intermodal equipment declared and marked out-of-service until all repairs required by the out-of-service notice have been satisfactorily completed. The term operate as used in this section shall include towing the vehicle or intermodal equipment, except that vehicles or intermodal equipment marked out-of-service may be towed away by means of a vehicle using a crane or hoist. A vehicle combination consisting of an emergency towing vehicle and an out-of-service vehicle shall not be operated unless such combination meets the performance requirements of this subchapter except for those conditions noted on the Driver Vehicle Examination Report.
49 CFR § 396.9
Personnel authorized to perform inspections. Every special agent of the FMCSA (as defined in appendix B to this subchapter) is authorized to enter upon and perform inspections of a motor carrier's vehicles in operation and intermodal equipment in operation.