It's neat that it's available online... wish more places did that. I think that this would be section that applies...

SECTION 1412
(12) Where suitable bike paths, horseback trails or other trails have been established on the right-of-way or parallel to and within one-fourth (¼) mile of the right-of-way of heavily traveled streets and highways, the Colorado Department of Transportation may, subject to the provisions of Section 43-2-135, C.R.S., by resolution or order, and the City Traffic Engineer may, where suitable bike paths, horseback trails or other trails have been established on the right-of-way or parallel to it within four hundred fifty (450) feet of the right-of-way of heavily traveled streets, by ordinance, determine and designate, upon the basis of an engineering and traffic investigation, those heavily traveled streets and highways upon which shall be prohibited any bicycle, animal rider, animal-drawn conveyance or other class or kind of nonmotorized traffic which is found to be incompatible with the normal and safe movement of traffic, and, upon such a determination, the Colorado Department of Transportation or the City shall erect appropriate official signs giving notice thereof; except that with respect to controlled access highways, the provisions of Section 42-4-1010(3), C.R.S., shall apply. When such official signs are so erected, no person shall violate any of the instructions contained thereon.