49 C.F.R. § 392.4 Drugs and other substances.
Title 49 - Transportation
(a) No driver shall be on duty and possess, be under the influence of, or use, any of the following drugs or other substances: (1) Any 21 CFR 1308.11 Schedule I substance; (2) An amphetamine or any formulation thereof (including, but not limited, to “pep pills,” and “bennies”); (3) A narcotic drug or any derivative thereof; or (4) Any other substance, to a degree which renders the driver incapable of safely operating a motor vehicle. (b) No motor carrier shall require or permit a driver to violate paragraph (a) of this section. (c) Paragraphs (a) (2), (3), and (4) do not apply to the possession or use of a substance administered to a driver by or under the instructions of a licensed medical practitioner, as defined in §382.107 of this subchapter, who has advised the driver that the substance will not affect the driver's ability to safely operate a motor vehicle. (d) As used in this section, “possession” does not include possession of a substance which is manifested and transported as part of a shipment. [61 FR 9567, Mar. 8, 1996, as amended at 62 FR 37153, July 11, 1997]
Title 49: Transportation
PART 392—DRIVING OF COMMERCIAL MOTOR VEHICLES
Subpart A—General
§ 392.4 Drugs and other substances.