*Featured image is a conceptual rendering, does not represent final design.

Projects will help mitigate potential future flooding and improve travel connections; expect lane closures beginning this March

The City of Boulder has begun construction on the 19th Street and Fourmile Canyon Creek Underpass Project, the first of two projects along 19th Street in north Boulder, to improve flood mitigation and multimodal transportation for all travelers.

Between Sumac and Upland avenues, travelers can currently expect periodic delays and flaggers guiding traffic in areas where the city has begun preparatory work for underpass construction. Later, travelers can expect long-term traffic impacts due to lane closures on 19th Street between Sumac and Upland avenues, anticipated to last for two years beginning on March 25, 2024:

  • The northbound lane is anticipated to close to travel starting from Monday, March 25.
  • Both the northbound and southbound lanes are anticipated to close to travel from 8 a.m. on Friday, March 29 through 5 p.m. on Saturday, March 30.
  • While the southbound lane is anticipated to reopen to travel after 5 p.m. on March 30, the northbound lane will remain closed to travel for the duration of the project.

View the project detour map for travel impacts to RTD transit, driving, biking and walking, and visit the city’s Cone Zones map for updates on traffic impacts.

Along with flood mitigation, this project will improve travel on 19th Street, an important multimodal connection in north Boulder. The city will construct a new bicycle and pedestrian underpass connecting Tamarack Avenue to Upland Avenue; replace and widen the 19th Street bridge over Fourmile Canyon Creek; improve transit stops; upgrade the on-street bikeable shoulder to a buffered bike lane; construct a new sidewalk; and install curb and gutter.

This project is the result of over a decade of work, including a Community and Environmental Assessment Process (CEAP) reviewed and recommended by boards and council. The CEAP provides the opportunity to assess a project design in consideration of community goals, city policies and plans, including the Boulder Valley Comprehensive Plan, and environmental, social and fiscal impacts. This project is funded by the city Utilities Department Stormwater Fund, Community, Culture, Resilience and Safety Tax, and Mile High Flood District.

This is the first of two projects along 19th Street. The second project will begin in summer 2024 to construct additional transportation improvements, with detours and impacts to be announced later this year. Learn more on the 19th Street Improvements webpage.

A detour map. Alt text provided in image caption.

View a large version of the map. View a Spanish version of the map
During construction, 19th Street will be closed to northbound vehicles, bikes, and RTD bus service at Sumac Avenue with a detour at Quince Avenue. The southbound 19th Street travel lane and RTD 204 bus stops will remain open. Northbound RTD 204 bus stops at Riverside Avenue and Upland Avenue will temporarily close. The nearest open northbound transit stops will be at Poplar Avenue and Avocado Road. Expect sidewalk closures, pedestrian detours, and delays when traveling in the area. The southbound sidewalk in front of Crest View Elementary will remain open at most times. If both the east and west sidewalks on 19th Street are closed due to work, a pedestrian detour will be in place through Crestview Park.