View an interactive map of the CO119 Safety, Mobility and Bikeway Project

Boulder County, Colo. – The CO 119/Diagonal Highway Safety, Mobility and Bikeway Project is under construction. When complete the Diagonal Highway will be transformed into fully multimodal transportation corridor.

Wondering what the CO 119/Diagonal Highway Safety, Mobility and Bikeway Project will look like when it is completed? View an interactive map of the nine-mile-long project and zoom in to see the bus rapid transit stations at 63rd Street, and Niwot Road and the bus rapid transit stop at CO 52, safety improvements and transformation of the intersection at CO 119 and CO 52 (Mineral Road), and the hard surface bikeway.

The project is a partnership with the Colorado Department of Transportation, the Regional Transportation District, Boulder County, the City of Longmont, and the City of Boulder.

Project Information Updates

Project teams from CDOT, Boulder County, and the City of Boulder are coordinating to limit travel disruptions and delays as much as possible while ensuring safety for construction workers and travelers. Sign up for CO 119/Diagonal Highway construction email updates.

View CDOT’s CO 119 Safety, Mobility & Bikeway webpage for more information on the intersection safety improvements at 55th Street, Monarch Road and other intersections. If you have questions or experience issues or problems on the Diagonal Highway, call the Project Hotline at 720-378-8083 or email co119safetyandmobility@gmail.com.

For more information or assistance, contact Alexandra Phillips, Boulder County Transportation Planner, at aphillips@bouldercounty.gov or 303-441-4520.

Boulder County wants to ensure that everyone has equal access to our programs, activities, and services. To request an Americans with Disability Act (ADA) accommodation, please email ada@bouldercounty.gov, or call 303-441-1386. If you need help in another language, please email cppfrontdesk@bouldercounty.gov or call 303-441-3930.