Douglas County to add continuous flow intersections on US 85 in Highlands Ranch

Douglas County transportation staff said the county will add continuous flow intersections, or CFIs, at three US 85 crossings in Highlands Ranch to increase lane capacity and improve safety.

In a county briefing, a staff member explained how the design changes the timing and geometry of left turns so through traffic on US 85 can travel with fewer interruptions. "Drivers turning left in a CFI should be prepared to enter the left lane in advance of the intersection much earlier than a standard intersection," the staff member said. The briefing added: "Remember, pay attention to the road signs and, of course, the speed limit."

The county presentation described the driver movement sequence used in a CFI: left-turning traffic shifts into designated turn lanes before the main intersection, then, when those lanes receive a green signal, they move to the outside of oncoming traffic and complete the left turn while through traffic continues uninterrupted. "This increases lane capacity for vehicles driving straight through," the staff member said.

Douglas County named three US 85 crossings where CFIs have been or will be installed: C-470, Town Center Drive and Highlands Ranch Parkway. The briefing emphasized that drivers will need to get into left-turn lanes earlier than at conventional intersections and to follow posted signs and speed limits.

The county did not provide a construction schedule, contract information or funding details in the briefing. Additional project timeline and funding information were not specified.