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US 287/Isabelle Road Intersection Safety Improvements

US Highway 287 & Isabelle Road Intersection Safety Improvements

Traffic on westbound Isabelle Road at US 287

Traffic on westbound Isabelle Road at US 287,

Boulder County Public Works, in partnership with the Colorado Department of Transportation, is reconstructing the intersection of US 287 and Isabelle Road to improve user safety, update operations, and increase multimodal access.

Construction in Progress – PHASE II of Isabelle Road CLOSURE starts Tuesday night, May 25

In order safely complete the intersection improvements, Isabelle Road will need to be closed to vehicles, bicycles, and pedestrians between N. 95th Street and US 287 for approximately five weeks starting Tuesday night, May 25. There is not enough room in the work zone to complete all safety improvements without closing Isabelle Road. See a map of Phase II travel restrictions. Detours will be posted. Residents of Isabelle will be able to access their homes from N. 95th Street during this phase.

  • Working hours – 7 a.m. to 7 p.m., Monday through Saturday
  • November 2020 through mid-July 2021
  • Lane closures and traffic shifts on US 287 will also be necessary
    • Expect Travel Delays – Alternative routes advised
  • Project Hotline = 720-745-6848
  • Project Email =


  • Widening of Isabelle Road from 109th Street (Town of Erie) to 800 feet west of US 287.
  • Stripe new buffered bike lanes both east and west on Isabelle Road across the intersection
  • Lengthen the existing turn lanes on Isabelle Road to reduce conflicts for waiting vehicles
  • Add dual left-turn lanes for westbound traffic
  • Replace existing traffic signals with new poles on raised islands
  • Add pedestrian crossings on all four corners
  • Install new street lights to improve visibility within project limits
  • Realign the Isabelle Road and 109th Street intersection to improve sight distance for both southbound and westbound traffic
  • Construct new wetlands northeast of the intersection to mitigate project impacts and improve habitat

Previous Public Meetings

  • March 3, 2020 – Updated designs were available for review. View plans for improvements
  • April 17, 2019 – Boulder County hosted a project open house to provide the public with an opportunity to review preliminary plans, ask questions, and provide comments.

Project Funding

This project is partially funded through a $2.6 million award from the Federal Highway Safety Improvement Program. The State of Colorado is providing $290,000, the Town of Erie will provide $300,000, and the remainder will be paid for using Countywide Transportation Tax funds.

Project Contact

  • Andrew Barth, Public Works Communications – 303-441-1032 or email