Median closure followed by permanent traffic shift planned for Airport Road and CO 119/Diagonal Highway intersection on April 13

Travel Advisory

April 9, 2026 - Northeastern Colorado - Airport Road median at CO 119 intersection transitioning to northbound one-way for CO 119 Safety, Mobility and Bikeway Improvements Project not be able to turn right from CO 52 onto Puritan Way during this work

Boulder County — On Monday, April 13, work will begin at the Airport Road median at CO 119/Diagonal Highway to convert the median into a permanent, one-way northbound road. Southbound travel in the median will be permanently prohibited starting at approximately 3 p.m., Monday, April 13.

Map of eventual look of Airport Road traffic which will only be northbound.
Map of eventual look of Airport Road traffic which will only be northbound.

Airport Road Full Median Closure

Monday, April 13, 7 a.m. to 3 p.m., there will be a one day, full closure of the Airport Road median, between northbound and southbound CO 119/Diagonal Highway, as crews prepare the area and begin safety improvements in the intersection. The median will be closed to all modes of transportation.

Detour Routes

  • Eastbound travelers will turn right onto southbound CO 119, turn left onto 83rd Street, then turn left onto northbound CO 119.
  • Westbound travelers will turn right onto northbound CO 119, turn left onto S Fordham Street, turn left onto southbound CO 119, then turn right to continue onto Airport Road.
  • During this closure, on April 13, both RTD bus stops at Airport Road and CO 119/Diagonal Highway (Stops #18005 and #19973) will be temporarily closed for pedestrian safety.
Map showing detours for full median closure of Airport Road on April 13.
Map showing detours for full median closure of Airport Road on April 13.

Map showing Phase 1 of the traffic shift after April 13 at 3 p.m.
Map showing Phase 1 of the traffic shift after April 13 at 3 p.m.

Permanent Traffic Shift and Phase 1 of Airport Road Safety Improvements

Then, immediately after the full median closure on Monday, April 13, at 3 p.m., the Airport Road and CO 119/Diagonal Highway intersection will transition to a one-way northbound road. This will also start the first phase of safety improvement work for the intersection, which will last approximately two months.

Phase 1 Traffic Impacts:

  • Right lane and right turn lane closure on Airport Road just north of CO 119/Diagonal Highway.
  • Northbound Airport Road median reduced to one lane. The two northbound left lanes on Airport Road, between northbound and southbound CO 119/Diagonal Highway, will be closed.
  • Partial closure of the trail at Airport Road between northbound and southbound CO 119/Diagonal Highway.

Detours and Alternate Routes:

  • When the Airport Road median becomes a northbound one-way road, travelers can use 83rd Street to access northbound CO 119/Diagonal Highway.
  • Travelers turning right from southbound Airport Road onto southbound CO 119/Diagonal Highway can turn from the southbound lane.
  • Pedestrians and cyclists will use the crosswalks on the east side of the intersection, travel southbound in the Airport Road median and turn left to connect with the trail in the median.
    • To provide this detour for pedestrians and cyclists, a lane will be closed in the Airport Road median, and a temporary trail surface will be added to connect to the trail between northbound and southbound CO 119/Diagonal Highway. Traffic barriers will protect the area in median from vehicles.

The Colorado Department of Transportation is implementing this change as part of the CO 119 Safety, Mobility and Bikeway Improvements Project to address significant safety concerns at the CO 119/Diagonal Highway intersection:

  • Data shows that 85% of crashes involving southbound Airport Road and CO 119 result in injury, with most occurring when vehicles attempt to turn left onto northbound CO 119.
  • Eliminating the southbound left turn onto northbound CO 119 (to Longmont) will reduce sideswipe and rear-end crashes, remove the need for a signal and bus queue jump lane at the current stop sign-controlled intersection, therefore improving overall corridor safety and mobility.

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 of transportation, and to make 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 preferred mode(s) of transportation.

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 connections between northbound and southbound CO 119, and underpasses or overpasses at major intersections for uninterrupted crossing
  • Physically reconfiguring the CO 52 intersection to improve safety and to accommodate new Bus Rapid Transit (BRT) stations and the Diagonal 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

Sign up for weekly project updates on the project website by following these five simple steps:

  • Visit the project website.
  • Select the "Stay Informed" graphic 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 select the submit button

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:

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 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!