Per the Colorado Driver Handbook:
- p. 20 - Rotary Island/Roundabout Lane: Yield to traffic already within the rotary island. Drive to the right and watch for directional signs and signals.
- p. 22 - Signaling: Before making any turn, whether the turn is into another roadway, a parking lot, another traffic lane, or leaving a parked position, it is extremely important that you signal. Your signal lets other drivers, cyclists, and pedestrians know your intentions. In urban or metropolitan areas, you must signal continuously for 100 ft. before making a turn or lane change. On four-lane highways where the posted speed limit is more than 40 m.p.h. you must signal for 200 ft.Failing to signal is a traffic violation.
Read more about Signaling and Rotary Island/Roundabout/Traffic Circle Driving at