C-470 & Quincy Roundabouts

About the Project:

Interchange improvement project at State Highway 470 and West Quincy Avenue in Jefferson County. Work includes adding a single lane roundabout with bypass lanes at the Quincy and C-470 northbound ramp intersection, and a T-intersection with traffic signal at the Quincy and C-470 southbound ramp intersection. Other work includes widening, building walls, adding signs, and making drainage improvements.

Project Benefits

  • Improve traffic flow to and from C-470 from Quincy Avenue
  • Construct a roundabout at the northbound ramp intersection, a proven method of safely managing traffic at certain intersection
  • Upgrade ramps to support increased traffic
  • Add a traffic signal to the southbound ramp intersection for improved safety

Work Schedule:

  • Work begins in mid-May with an anticipated duration of 18 month
  • Project hours will be 7 a.m. to 5 p.m. Monday to Friday with extended hours in the summer month
  • Overnight and weekend work also expected.

Traffic Impacts:

Motorists can expect the following impacts during the period of construction:

  • Periodic on and off ramp closures to and from C-470 at Quincy Ave during off-peak daytime as well as overnight hours
  • Some closures of half the existing Quincy Ave over C-470 bridge will be taken for roundabout and other construction, with two-way traffic maintained and 12-ft width restriction in place
  • A single lane closure on northbound C-470 will exist later in the project for sign work
  • Onsite detour pavement will be built to route traffic around the proposed roundabout location
  • Other detour routes will be marked for use during later phases of construction
  • Signs and construction devices will be present to alert the public to the work zone, closures and restrictions
  • All construction schedules are weather dependent and subject to change
  • Refer to COtrip.org for real-time travel conditions and road closures

Work this Week & Lane Closures C-470 & Quincy Roundabouts

Project Facts

  • Construction Cost: $6.2 Million
  • Contractor: Villalobos Concrete, Inc.
  • Timeline: April through October 2024
  • Location: C-470 & West Quincy Avenue 
    • Nearest Town/City: Denver
    • Mile Point(s): MP 6.10 to MP 6.80
    • County: Jefferson County
C-470 Quincy Roundabouts project location map
C-470 Quincy Roundabouts project location