Transportation. Part391:Qualifications of drivers and longer combination vehicle (LCV) driver instructors. SubpartE:Physical qualifications and examinations. Section391.41:Physical qualifications for drivers.
(a)(1)(i) A person subject to this part must not operate a commercial motor vehicle unless he or she is medically certified as physically qualified to do so, and, except as provided in paragraph (a)(2) of this section, when onduty has on his or her person the original, or a copy, of a current medical examiner’s certificate that he or she is physically qualified to drive a commercial motor vehicle.？NOTE: Effective December 29, 1991, the FMCSA Administrator determined that the new Licencia Federal de Conductor issued by the United Mexican States is recognized as proof of medical fitness to drive a CMV.