CO 119 intersections and 63rd Street improvements update

On Aug. 13, the Boulder County Community Planning & Permitting Department hosted a webinar to provide detailed updates on various CO 119 (the "Diagonal") intersections and design options for the 63rd Street bike/pedestrian overpass. The intersections discussed included both unsignalized and signalized locations. The unsignalized intersections covered were 55th Street, Monarch Road, Oxford Road, 83rd Street, and Fordham Street, while the signalized intersections included Airport Road, Niwot Road, 63rd Street, CO 52, and Jay Road.

The CDOT CO 119 Safety & Mobility Improvement Project will construct a nine-mile bikeway between Boulder and Longmont, as well as Bus Rapid Transit stations and bus bypass lanes for faster, more reliable buses and intersection safety improvements.

The project is designed to integrate with other active multimodal projects on the corridor, including the City of Longmont Coffman Street Mobility Improvements, Boston Avenue Bridge Replacement, 1st Avenue and Main Street Station Transit Revitalization Project , and the City of Boulder 28th Street Improvement Projects. The integration aims to ensure community members may safely and reliably travel throughout the corridor using their mode(s) of choice. Construction on the project will begin later this year.

The unsignalized Monarch Road and Oxford Road/83rd Street intersections on CO 119 are of particular interest to Niwot residents. At Monarch Road, the southbound intersection saw 23 broadside crashes resulting in injury, a frequency notably higher than the statewide average. On the northbound side of Monarch Road, the broadside crashes involved primarily eastbound vehicles crossing northbound CO 119 or turning left onto northbound CO 119.

Improvements to the Monarch Road and CO 119 intersection include converting Monarch Road to a right-in, right-out configuration, which will reroute existing through traffic to Niwot Road to the north (0.65 miles) and to CO 52 to the south (0.45 miles). In addition, the proposal includes extending the acceleration and deceleration lanes on CO 119 to meet State Highway Access Code criteria and removing the at-grade crossing with the proposed bike path.

At the Oxford Road and 83rd Street intersection, there was one broadside crash during the five-year study period, where an eastbound vehicle failed to yield the right-of-way to southbound traffic while crossing CO 119. The crash data also indicated that seven of the crashes involved northbound traffic, including eastbound vehicles on North 83rd Street failing to yield the right-of-way to northbound traffic when crossing CO 119 after stopping at the stop sign in the median.

The proposed improvements include extending the deceleration lanes on CO 119 to meet State Highway Access Code criteria and an LED flashing stop sign to alert drivers of an approaching intersection. If the current crash pattern persists or worsen, signalizing the 83rd Street northbound CO 119 intersection may be considered. Implementing a right-in/right-out at this location would be a challenge due to intersection configuration and out-of-direction travel distances.

Improvements to the signalized Airport Road and CO 119 intersection include eliminating left turns from Airport Road onto CO 119, converting Airport Road between northbound and southbound CO 119 to a one-way northbound, and eliminating left turns from southbound CO 119 onto southbound Airport Road.

Signalized Niwot Road intersection improvements will include new Bus Rapid Transit (BRT) stations with bus queue bypass lanes for both directions of CO 119, expanding and improving the existing Park-n-Ride on the north side of Niwot Road and preserving bike lanes on Niwot Road while developing bicycle and pedestrian access to the bikeway and BRT stations.

Boulder County presented six architectural design options for the 63rd Street overpass: "Colorado Historic," "Rustic/Earthy," "Front Range Modern," "Traditional," "Clean and Simple," and "Bold/Architectural/Elegant." Due to a conflict with an underground waterline, the underpass initially planned in this location will be replaced with an overpass. Boulder County is encouraging residents to complete ahttps://www.surveymonkey.com/r/HKLX6G9" target="_blank"> survey, which will be used to help guide the direction of the design concepts. Take the survey at https://www.surveymonkey.com/r/HKLX6G9. These concepts will be presented to the public for another round of feedback in the fall of 2024.

An audience member requested an update regarding the proposed Niwot Road underpass, connecting the proposed RTD Park-N-Ride with Second Avenue in downtown Niwot.

Stacey Proctor, Boulder County's project manager, stated in an email, "We heard that the Niwot Local Improvement District (LID) is planning to submit a proposal to Burlington Northern Santa Fe Railway to assess the feasibility of an underpass beneath the railroad tracks. The Niwot LID has also requested that the design of Option 3A be put on hold. The county is reviewing this request and considering all relevant factors. We hope to know more about our proposed next steps in the next few weeks."