CO Rev Stat § 42-4-1305.5 (2020)
(1) Definitions. As used in this section, unless the context otherwise requires:
(a) “Marijuana” shall have the same meaning as in section 16 (2) (f) of article XVIII of the state constitution.
(b) “Motor vehicle” means a vehicle driven or drawn by mechanical power and manufactured primarily for use on public highways but does not include a vehicle operated exclusively on a rail or rails.
(c) “Open marijuana container” means a receptacle or marijuana accessory that contains any amount of marijuana and:
(I) That is open or has a broken seal;
(II) The contents of which are partially removed; and
(III) There is evidence that marijuana has been consumed within the motor vehicle.
(d) “Passenger area” means the area designed to seat the driver and passengers, including seating behind the driver, while a motor vehicle is in operation and any area that is readily accessible to the driver or a passenger while in his or her seating position, including but not limited to the glove compartment.
(2) (a) Except as otherwise permitted in paragraph (b) of this subsection (2), a person while in the passenger area of a motor vehicle that is on a public highway of this state or the right-of-way of a public highway of this state may not knowingly:
(I) Use or consume marijuana; or
(II) Have in his or her possession an open marijuana container.
(b) The provisions of this subsection (2) shall not apply to:
(I) Passengers, other than the driver or a front seat passenger, located in the passenger area of a motor vehicle designed, maintained, or used primarily for the transportation of persons for compensation;
(II) The possession by a passenger, other than the driver or a front seat passenger, of an open marijuana container in the living quarters of a house coach, house trailer, motor home, as defined in section 42-1-102 (57), or trailer coach, as defined in section 42-1-102 (106) (a);
(III) The possession of an open marijuana container in the area behind the last upright seat of a motor vehicle that is not equipped with a trunk; or
(IV) The possession of an open marijuana container in an area not normally occupied by the driver or a passenger in a motor vehicle that is not equipped with a trunk.
(c) A person who violates the provisions of this subsection (2) commits a class A traffic infraction and shall be punished by a fine of fifty dollars and a surcharge of seven dollars and eighty cents as provided in this section and section 42-4-1701 (4) (a) (I) (N).
(3) Nothing in this section shall be construed to preempt or limit the authority of any statutory or home rule town, city, or city and county to adopt ordinances that are no less restrictive than the provisions of this section.