49 C.F.R. § 391.1 : Transportation — OTHER REGULATIONS RELATING TO TRANSPORTATION — FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION — FEDERAL MOTOR CARRIER SAFETY REGULATIONS — QUALIFICATIONS OF DRIVERS AND LONGER COMBINATION VEHICLE (LCV) DRIVER INSTRUCTORS — GENERAL — Scope of the rules in this part; additional qualifications; duties of carrier-drivers

(a) The rules in this part establish minimum qualifications for persons who drive commercial motor vehicles as, for, or on behalf of motor carriers. The rules in this part also establish minimum duties of motor carriers with respect to the qualifications of their drivers.
(b) An individual who meets the definition of both a motor carrier and a driver employed by that motor carrier must comply with both the rules in this part that apply to motor carriers and the rules in this part that apply to drivers.

49 C.F.R. §391.1

35 FR 6460, 4/22/1970, as amended at 53 FR 18057, 5/19/1988; 60 FR 38744, 7/28/1995; 80 FR 59074, 10/1/2015