The driver of a motor vehicle intending to turn shall do so as follows:
Right Turns: Both the approach for a right turn and a right turn shall be made as close as practicable to the right hand curb or edge of the roadway.
Left Turns: The driver of a motor vehicle intending to turn left shall approach the turn in the extreme left-hand lane lawfully available to traffic moving in the direction of travel of such vehicle. Whenever practicable, the left turn shall be made to the left of the center of the intersection so as to leave the intersection or other location in the extreme left-hand lane lawfully available to traffic moving in the same direction as such vehicle on the roadway being entered.
Two-way Left Turn Lanes: Where a special lane for making left turns by drivers proceeding in opposite directions has been indicated by official traffic control devices, a left turn shall not be made from any other lane, and a motor vehicle shall not be driven in said special lane except when preparing for or making a left turn from or onto the roadway or when preparing for or making a U-turn when otherwise permitted by law.
Official traffic control devices may be placed and thereby require and direct that a different course from that specified in this section be traveled by turning motor vehicles, and, when such devices are so placed, no driver shall turn a motor vehicle other than as directed and required by such devices.
Cross reference: Section 42-4-901, C.R.S.