Two upcoming road closures will affect travel along Colorado Highway 119/Diagonal Highway in Boulder County starting the week of September 8, as part of the ongoing CO 119 Safety, Mobility and Bikeway Improvements Project. The closures will take place at 2nd Avenue in Niwot and the Oxford Road median between northbound and southbound lanes.
The Colorado Department of Transportation (CDOT) will begin a full closure of 2nd Avenue at northbound CO 119/Diagonal Highway at 9 p.m. on Tuesday, September 9. This closure is necessary for crews to complete median-widening work that will support a future Bus Rapid Transit lane. Local access on 2nd Avenue will be maintained between Murray Street and the railroad tracks east of the highway. All other access through this section will be restricted for all forms of transportation until the end of 2025. Travelers are advised to use Niwot Road to reach northbound CO 119/Diagonal Highway.
A second closure will begin at 9 p.m. on Friday, September 12, when CDOT implements a temporary full closure of the Oxford Road median between northbound and southbound CO 119/Diagonal Highway. This closure is expected to last until mid-October and will restrict all modes of transportation from accessing northbound CO 119 via Oxford Road during this period.
Crews will use this time to construct a raised bikeway crossing and widen the road to extend deceleration lanes. Following completion, an adjacent full closure of the nearby 83rd Street median is scheduled for several weeks, with further information to be provided before it begins.
Detour routes have been established for drivers and cyclists:
Westbound travelers should pass Oxford Road on northbound CO 119, turn left onto Airport Road median, then left onto southbound CO 119 before turning right to reach Oxford Road.
Eastbound travelers and cyclists should turn right onto southbound CO 119/Diagonal Highway, then left onto Niwot Road median, followed by another left turn to access northbound CO 119.
Work schedules may change depending on conditions.
Traffic along Diagonal Highway between Boulder and Longmont is projected to increase by about a quarter by the year 2040. Higher traffic volumes can contribute to more congestion, delays, emissions from vehicles, and potentially more crashes (https://www.codot.gov/projects/co119-mobility).
According to CDOT: “The CO 119 Safety, Mobility and Bikeway Project is constructing safety, mobility and bikeway improvements to make traveling through the corridor safer for all modes and transit travel faster and more reliable. The project is designed to integrate with other active multimodal projects on the corridor to ensure community members can safely and reliably travel throughout the corridor using their mode(s) of choice.”
Project objectives include improving overall corridor safety; maximizing capacity for moving people; increasing intersection efficiency; reducing transit times; boosting ridership; enhancing operational efficiency; and expanding bicycle commuting opportunities with better connectivity.
Some specific improvements include new signage, striping, signal timing adjustments at major intersections such as Jay Road, Niwot Road, Airport Road, adding commuter bikeways with connection points under or over major intersections for uninterrupted crossing, reconfiguring intersections like Colorado Highway 52 for greater safety and accommodation of new Bus Rapid Transit stations as well as Boulder County’s Commuter Bikeway (https://www.codot.gov/projects/co119-mobility).
Throughout construction activities along CO 119/Diagonal Highway, lane shifts or closures may occur but general configuration will remain similar. Speed limits will be reduced in construction zones.
Kraemer North America serves as general contractor for this project.
For updates or questions regarding these closures or ongoing work on the project visit https://www.codot.gov/projects/co119-mobility or contact the project team via phone at (720) 378-8083 or email [email protected].
