C.R.S. § 42-4-1005: Limitations on overtaking on the left.

(1) No vehicle shall be driven to the left side of the center of the roadway in overtaking and passing another vehicle proceeding in the same direction unless authorized by the provisions of this article and unless such left side is clearly visible and is free of oncoming traffic for a sufficient distance ahead to permit such overtaking and passing to be completed without interfering with the operation of any vehicle approaching from the opposite direction or any vehicle overtaken. In every event the overtaking vehicle must return to an authorized lane of travel as soon as practicable and, in the event the passing movement involves the use of a lane authorized for vehicles approaching from the opposite direction, before coming within two hundred feet of any approaching vehicle.

(2) No vehicle shall be driven on the left side of the roadway under the following conditions:

(a) When approaching or upon the crest of a grade or a curve in the highway where the driver's view is obstructed within such distance as to create a hazard in the event another vehicle might approach from the opposite direction;

(b) When approaching within one hundred feet of or traversing any intersection or railroad grade crossing; or

(c) When the view is obstructed upon approaching within one hundred feet of any bridge, viaduct, or tunnel.

(3) The department of transportation and local authorities are authorized to determine those portions of any highway under their respective jurisdictions where overtaking and passing or driving on the left side of the roadway would be especially hazardous and may, by appropriate signs or the beginning and end of solid yellow line pavement or line pavement markings on the roadway, indicate the beginning and end of the zones. Where signs or solid yellow line or line pavement markings are in place to define a no-passing zone and the signs or markings are clearly visible to an ordinarily observant person, a driver shall not drive on the left side of the roadway within the no-passing zone or on the left side of any pavement striping designed to mark the no-passing zone throughout its length.

(3.5) Within existing resources, the department of transportation shall prioritize installing signage on roadways with increased crashes resulting from incidents of illegal overtaking on the left in no-passing zones. Increased crashes resulting from incidents of illegal overtaking on the left are measured as an increase of crashes resulting from incidents of illegal overtaking on the left in no-passing zones over the previous year's number of crashes as reported by the statewide crash data listing maintained by the department of transportation, as required by 23 U.S.C. secs. 148 and 405.

(4) The provisions of this section shall not apply:

(a) Upon a one-way roadway;

(b) Under the conditions described in section 42-4-1001 (1)(b);

(c) To the driver of a vehicle turning left into or from an alley, private road, or driveway when such movement can be made in safety and without interfering with, impeding, or endangering other traffic lawfully using the highway; or

(d) To the driver of a vehicle passing a bicyclist moving the same direction and in the same lane when such movement can be made in safety and without interfering with, impeding, or endangering other traffic lawfully using the highway.

(5) Any person who violates any provision of this section commits a class A traffic infraction.