US 85 Corridor Improvements (Douglas County)

About the Project:

Douglas County and the Colorado Department of Transportation are partnering on a multimodal transportation project to increase mobility along 2.5 miles of US 85 (Santa Fe Drive) from Highlands Ranch Parkway to C-470. Construction started in early October 2022. The project will widen US 85 from four to six lanes, replace and widen the existing bridge that carries US 85 over C-470. Major US 85 intersection improvements will occur at Highlands Ranch Parkway, Town Center Drive, the C-470 Interchange ramps and at County Line Road.

Aerial image - Douglas County US 85 & C-470 Phase 2 project location
Douglas County US 85 C-470 Phase 2 Rendering

Project Benefits

  • Reducing congestion with an additional through lane in each direction of US 85 and auxiliary lanes at key intersections
  • New roadway pavement and installation of raised medians to reduce conflicts throughout the corridor
  • New below-grade trail crossings at US 85 for the C-470 and High Line Canal Trails and a new shared path on the east side of US 85
  • Multi-modal improvements including new bus stop shelters
  • Relocation for various utility lines to facilitate future community growth
  • New closed storm water sewer system with water quality ponds

Work Schedule:

  • Work will last from Fall 2022 through Fall 2025
  • Working hours 6 a.m. through 6 p.m., Monday to Saturday
  • Overnight and weekend work is expected

Traffic Impacts:

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

  • Daily lane closures in both directions US 85 between County Line Road and Highlands Ranch Parkway from 9 a.m. to 3 p.m.
  • Lane closures on C-470 on- and off-ramps at US 85
  • Lane shifts on US 85
  • Reduced speeds through the work zone
  • Narrowed lanes and reduced shoulders on US 85 and C-470
  • Flagging operations will be in place along local roads to safely direct traffic through construction activities
  • Full closure of the C-470 and High Line Canal Trails at US 85.
  • Signs will be posted to alert motorists to the closures and available detour routes
  • Refer to for real-time travel conditions and road closures

Project Facts

  • Total Construction Cost: $108 million
  • Contractor: Kraemer NA
  • Timeline: Fall 2022 to Fall 2025
  • Location: US 85 (South Santa Fe Drive): Highlands Ranch Parkway to C-470
    • Closest City:  Highlands Ranch
    • Mile Points: MP 201 to MP 199.5
    • County: Douglas