Closures at Second Avenue and 83rd Street median near CO 119/Diagonal Highway start this week, Oxford Road median closure postponed

Travel Advisory

Boulder County - Two road closures are set to begin this week as work continues on the Colorado Highway 119 Safety, Mobility and Bikeway Improvements Project - one on 2nd Avenue in Niwot and another on the 83rd Street median between northbound and southbound Highway 119/Diagonal Highway.

Crews originally planned to close the Oxford Road median on Friday, Sept. 12, for several weeks, with a closure of the 83rd Street median to follow. Due to upcoming drainage operations, the project pivoted and will now close the 83rd Street median on Wednesday, Sept. 10, and the Oxford Road median closure has been postponed to spring 2026.

2nd Avenue Closure

Beginning at 9 p.m. on Tuesday, Sept. 9, the Colorado Department of Transportation will implement a temporary full closure of 2nd Avenue in Niwot at northbound CO 119/Diagonal Highway to allow crews to complete median-widening work for the future Bus Rapid Transit lane. Local access on 2nd Avenue will be maintained between Murray Street and the railroad tracks just east of the highway. The 2nd Avenue closure will remain in place for all modes of transportation until the end of 2025. During this time, travelers should use Niwot Road to access northbound CO 119/Diagonal Highway.

83rd Street Closure

Beginning at 9 p.m. on Wednesday, Sept. 10, CDOT will implement a temporary full closure of the 83rd Street median between northbound and southbound CO 119/Diagonal Highway. This closure will be in place for all modes of transportation for several weeks. During this time, access to northbound and southbound CO 119 through the 83rd Street median will be prohibited.

While the median is closed, crews will construct a raised bikeway crossing and widen the road to extend the deceleration lanes.

Please follow the posted detour routes for alternate access. A designated cyclist detour is also in place.

Detour Routes:

• Northbound CO 119/Diagonal Highway travelers intending to turn left on 83rd Street will pass 83rd Street, continue on northbound CO 119, turn left onto the Airport Road median and turn left and continue onto southbound CO 119.
• Southbound CO 119/Diagonal Highway travelers intending to turn left onto 83rd Street will pass 83rd Street, continue on southbound CO 119, turn left onto the Niwot Road median and turn left to continue onto northbound CO 119. This will also be the signed detour route for cyclists.

Work schedules are subject to change and can vary based on conditions.

What is the CO 119 Safety, Mobility and Bikeway Improvements Project?

By the year 2040, the Diagonal Highway between Boulder and Longmont is expected to see a 25% increase in vehicular traffic. Increased traffic can result in more congestion, delays, tailpipe emissions and potentially more crashes.

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.

This project will:

• Improve safety in the whole corridor.
• Maximize the number of people able to move through the corridor.
• Maximize intersection operational efficiency.
• Improve transit travel times and increase ridership.
• Maximize corridor-wide operational efficiency.
• Increase opportunities for bicycle commuting and connectivity to the bicycle and pedestrian network.

Specific corridor improvements include:

• New signage, striping and improved signal timing at all pedestrian crossings at signalized intersections.
• Signal timing adjustments at key intersections (Jay Road, 63rd Street, Colorado Highway 52, Niwot Road and Airport Road).
• Adding a commuter bikeway and several local connection points between northbound and southbound CO 119, and underpasses or overpasses at major intersections for uninterrupted crossing.
• Physically reconfiguring the Colorado Highway 52 intersection to improve safety and to accommodate new Bus Rapid Transit stations and Boulder County's Commuter Bikeway between the northbound and southbound travel lanes.
• Changing access at Airport Road and CO 119 to reduce crashes and improve safety and traffic flow.

During construction, CO 119/Diagonal Highway will largely remain configured as it currently operates, with various lane shifts and closures. Additional information will be provided prior to any major closures or detour routes throughout the project duration. In addition, lane and shoulder widths will be minimized. The speed limit will be reduced. Please pay attention and follow posted speed limits. Kraemer North America is the General Contractor for this project.

CO 119 Safety, Mobility and Bikeway Improvements Project Contact Information

• Project phone line: 720-378-8083
• Project email: [email protected]
• Project website: codot.gov/projects/co119mobility
• Sign up for weekly project updates on the project website by following these five simple steps:
  • Visit the project website.
  • Click on the "Stay Informed" box on the right side of the page.
  • From there, scroll to the "Construction Updates & News Releases" section and select "Subscribe to Construction Updates".
  • Enter your email address, then select "Northeast Colorado" as the region, check "Front Range I-25 Corridor" and "CO 119 Safety & Mobility Improvements.".
  • Scroll to the bottom and hit submit.

Know Before You Go

Travelers are urged to "know before you go." Gather information about weather forecasts and anticipated travel impacts and current road conditions prior to hitting the road. CDOT resources include:

• Road conditions and travel information: COtrip.org
• Download the COtrip Planner app: bit.ly/COtripapp
• Sign up for project or travel alerts: bit.ly/COnewsalerts
• Check scheduled construction lane closures: bit.ly/laneclosures
• Connect with @ColoradoDOT on social media: X, Facebook, Instagram and YouTube

Remember: Slow For The Cone Zone

The following tips are to help you stay safe while traveling through maintenance and construction work zones.

• Do not speed in work zones. Obey the posted speed limits.
• Stay Alert! Expect the unexpected.
• Watch for workers. Drive with caution.
• Don't change lanes unnecessarily.
• Avoid using mobile devices such as phones while driving in work zones.
• Turn on headlights so that workers and other drivers can see you.
• Be especially alert at night while driving in work zones.
• Expect delays, especially during peak travel times.
• Allow ample space between you and the car in front of you.
• Anticipate lane shifts and merge when directed to do so.
• Be patient!

Download the COtrip App!

The new free COtrip Planner mobile app was designed to meet the growing trend of information on mobile and tablet devices for the traveling public. The COtrip Planner app provides statewide, real-time traffic information, and works on mobile devices that operate on the iOS and Android platforms. Visit the Google Play Store (Android devices) or the Apple Store (iOS devices) to download!