C.R.S. § 42-4-1503

(1) All motorcycles are entitled to full use of a traffic lane, and no motor vehicle shall be driven in such a manner as to deprive any motorcycle of the full use of a traffic lane. This subsection (1) shall not apply to motorcycles operated two abreast in a single lane. (2) The operator of a motorcycle or autocycle shall not overtake or pass in the same lane occupied by the vehicle being overtaken. (3) A person shall not operate a motorcycle or autocycle between lanes of traffic or between adjacent lines or rows of vehicles. (4) Motorcycles shall not be operated more than two abreast in a single lane. (5) Subsections (2) and (3) of this section shall not apply to police officers in the performance of their official duties. (6) Any person who violates any provision of this section commits a class A traffic infraction.