Originally Posted by cyccommute

Colorado State statute

(5) Any person riding a bicycle shall ride in the right-hand lane. When being overtaken by another vehicle, such person shall ride as close to the right-hand side as practicable. Where a paved shoulder suitable for bicycle riding is present, persons operating bicycles shall ride on the paved shoulder. These provisions shall apply, except under any of the following situations:
(a) When overtaking and passing another bicycle or vehicle proceeding in the same direction;
(b) When preparing for a left turn at an intersection or into a private road or driveway;
(c) When reasonably necessary to avoid hazardous conditions, including, but not limited to, fixed or moving objects, parked or moving vehicles, pedestrians, animals, or surface hazards.

Practicable means in 'as feasible'. It doesn't mean that you have to ride as far to the right as possible at all times but as far to the right as you can reasonably and safely do so.