Stage 1 fire restrictions, enacted for unincorporated areas of western Boulder County.

News Archive

December 8, 2023

Learn About and Comment on the Diagonal Hwy. CO 119 Safety, Mobility and Bikeway Project

Project update available online, attend an open house on Dec. 13 in Niwot

Boulder County, Colo. - Boulder County, the Colorado Department of Transportation, the Regional Transportation District, and the cities of Boulder and Longmont are implementing safety and mobility improvements along CO119 that will make traveling through the corridor safer for all modes, as well as faster and more reliable for public transit. The project construction will begin in 2024.

Three online presentation videos are available for the public to get an update on the project, learn more about the safety improvements to the unsignalized intersections and provide feedback on options for a potential pedestrian and bike underpass connecting to 2nd Avenue in Niwot.

The videos and a community comment form are currently available on the CDOT CO 119 Safety, Mobility and Bikeway Project webpage.

In addition, an in-person open house will be held on Dec. 13 from 5:30-7 p.m. at Lefthand Grange, 195 2nd Ave, in Niwot.

What: Open House for the Diagonal CO Hwy. 119 Safety, Mobility and Bikeway Project
When: Wednesday, Dec. 13 from 5:30-7 p.m. .
Where: Left Hand Grange, 195 2nd Ave., Niwot, CO
Who: Anyone who travels on or across the Diagonal Hwy. between Boulder and Longmont via any mode of transportation, or anyone interested in transportation and land use planning in Boulder County.

“By the year 2040, the Diagonal Highway between Boulder and Longmont is expected to see a 25 percent increase in vehicular traffic,” said Heather Paddock, northeast regional transportation director. “Increased traffic can result in more congestion, delays, tailpipe emissions and potentially more crashes. CDOT, RTD and Boulder County are taking action to mitigate these outcomes and expand transportation options beyond private automobiles.”

In the coming months, the project team will be completing the proposed design, planning the potential phasing of construction, and establishing a schedule for construction.

For more information, visit the CDOT CO 119 Safety, Mobility and Bikeway Project and the Boulder County CO 119 Bikeway Design Project webpages, or email

CDOT CO Highway 119 overview video image