C.R.S. § 42-4-238: Blue and red lights - illegal use or possession.

(1) A person shall not be in actual physical control of a vehicle, except an authorized emergency vehicle as defined in section 42-1-102 (6), that the person knows contains a lamp or device that is designed to display, or that is capable of displaying if affixed or attached to the vehicle, a red or blue light visible directly in front of the center of the vehicle.

(2) It shall be an affirmative defense that the defendant was:

(a) A peace officer as described in section 16-2.5-101, C.R.S.; or

(b) In actual physical control of a vehicle expressly authorized by a chief of police or sheriff to contain a lamp or device that is designed to display, or that is capable of displaying if affixed or attached to the vehicle, a red or blue light visible from directly in front of the center of the vehicle; or

(c) A member of a volunteer fire department or a volunteer ambulance service who possesses a permit from the fire chief of the fire department or chief executive officer of the ambulance service through which the volunteer serves to operate a vehicle pursuant to section 42-4-222 (1)(b); or

(d) A vendor who exhibits, sells, or offers for sale a lamp or device designed to display, or that is capable of displaying, if affixed or attached to the vehicle, a red or blue light; or

(e) A collector of fire engines, fire suppression vehicles, or ambulances and the vehicle to which the red or blue lamps were affixed is valued for the vehicle's historical interest or as a collector's item.

(3) A violation of this section is a class 2 misdemeanor.