Kentucky Revised Statutes Title XXIV. Public Utilities § 281A.090.Restrictions on driving

(1) Except when driving under a commercial learner's permit and accompanied by the holder of commercial driver's license valid for the vehicle being driven, no person shall drive a commercial motor vehicle on the highways of this state unless the person holds a valid commercial driver's license with applicable endorsements valid for the vehicle he or she is driving.

(2) No person shall drive a commercial motor vehicle on the highways of this state while his or her driving privilege for a commercial or noncommercial motor vehicle is suspended, revoked, or canceled, or while he or she is subject to a disqualification, or in violation of an out-of-service order.

(3) The licensee shall have in his or her immediate possession at all times when operating a motor vehicle his or her commercial driver's license, and shall display the license upon demand to the Transportation Cabinet, a license examiner, a peace officer, a State Police officer, or an inspector or officer of the Department of Vehicle Regulation. It shall be a defense to a violator of this subsection if the person so charged produces in court a commercial driver's license, issued to him or her before his or her arrest or violation and which was valid at that time.