Colorado Statutes 42-4-1013. Passing lane - definitions - penalty

(1) A person shall not drive a motor vehicle in the passing lane of a highway if the speed limit is sixty-five miles per hour or more unless such person is passing other motor vehicles that are in a nonpassing lane or turning left, or unless the volume of traffic does not permit the motor vehicle to safely merge into a nonpassing lane.

(2) For the purposes of this section:

(a) "Nonpassing lane" means any lane that is to the right of the passing lane if there are two or more adjacent lanes of traffic moving in the same direction in one roadway.

(b) "Passing lane" means the farthest to the left lane if there are two or more adjacent lanes of traffic moving in the same direction in one roadway; except that, if such left lane is restricted to high occupancy vehicle use or is designed for left turns only, the passing lane shall be the lane immediately to the right of such high occupancy lane or left-turn lane.

(3) A person who violates this section commits a class A traffic infraction.