CDOT extends full closure of Boulder Canyon on Monday, Aug. 5

August 2, 2019 - Northeastern Colorado

BOULDER COUNTY – Colorado Department of Transportation, in partnership with Zak Dirt, is extending the closure of Colorado Highway 119 Boulder Canyon on Monday, Aug. 5, in order to address several large boulders expected to fall in the regular blast.

The closure, from Arapahoe Avenue to Fourmile Canyon Road, is now scheduled from 10 a.m. to midnight, but if the work is completed earlier, the road will be opened earlier.

After analyzing the nature of the canyon rock and the blast removal plan for Monday, CDOT determined that several large boulders will come down when the removal takes place. These rocks are anticipated to be so large that they will likely require a second blast on the ground, in order to be removed from the highway.

During this closure, motorists will be required to use the alternate routes of CO 72 or Lefthand Canyon Drive. Local resident access will be maintained between Fourmile Canyon Road and Nederland. Crews will work as quickly as they can, and if the work is completed before midnight, the highway will reopen early. 

Due to the unpredictable nature of blasting operations, it is difficult to predict how the rock will react to the blasts. CDOT engineers and geotechnical experts are continuously monitoring and adjusting the plans in order to minimize public impact, but will always utilize a full closure to maintain public safety. 

On Tuesday, Aug. 6, full closures for blasting will return to the regularly scheduled 10 a.m. to 2 p.m.

To date, approximately 20,000 cubic yards of material has been removed from the canyon walls to make room for a more flood resilient canyon corridor. It’s all part of CDOT’s Whole System – Whole Safety initiative.

CDOT and the entire project team want to thank the surrounding communities for their patience throughout this project. As a reminder, motorists should always check the website, sign up text alerts and call the hotline before the travel the canyon to stay informed on current conditions. (See below for a list of communication resources.)


Construction crews are repairing a 15-mile stretch of CO 119 between Boulder and Nederland, which was damaged during flooding in 2013. The project began in March 2019 and is scheduled for completion in early 2021.

The project includes significant highway repairs, such as resurfacing 13 miles of highway and entirely replacing two miles of highway, building concrete islands to improve the roundabout in Nederland, replacing multiple pipes conveying stormwater drainage under the highway, scaling rock in selected areas to reduce rockfalls on the highway, and replacing 29,000 linear feet of concrete or metal guardrail. The project, in partnership with Boulder County, will also extend and reinforce sections of the Boulder Canyon Trail. The 10-foot-wide, multi-use trail will be extended from Four Mile Canyon to Chapman Drive, adding two new bike-friendly tunnels under the highway and approximately 3,500 feet of length to the trail.


The closures and other impacts to CO 119 are announced weekly. There are several ways to get updates on the project:

  • An email is sent as a traffic advisory when the roadway impacts change on a week-to-week basis. To subscribe to these emails, please email the public information team at [email protected]

  • Subscribe to the free texting service by texting CO119 to the number 21000. This service will primarily be used to communicate upcoming closures on the highway. 

  • The project number (720-500-9912) has an outgoing message that is updated weekly with updates, a summary of impacts to the highway and trail, and estimated delay times through the canyon. 

  • The CDOT project web page will be updated with the latest traffic advisory as they are distributed. There are several maps of the project on this page. You can see more maps in the Telephone Town Hall supporting documents. 

  • CDOT also maintains road closure updates on, an interactive map on the CDOT system


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!


To heighten safety awareness, CDOT recently announced its Whole System — Whole Safety initiative. This project takes a systematic statewide approach to safety combining the benefits of CDOT’s programs that address driving behaviors, our built environment and the organization's operations. The goal is to improve the safety of Colorado’s transportation network by reducing the rate and severity of crashes and improving the safety of all transportation modes. The program has one simple mission—to get everyone home safely.


CDOT has approximately 3,000 employees located throughout Colorado, and manages more than 23,000 lane miles of highway and 3,429 bridges. CDOT also manages grant partnerships with a range of other agencies, including metropolitan planning organizations, local governments and airports. It also administers Bustang, the state-owned and operated interregional express service. Gov. Polis has charged CDOT to further build on the state’s intermodal mobility options.