There are two related projects in the area. Projects will help mitigate potential future flooding and improve multimodal travel connections

The 19th Street and Fourmile Canyon Creek Underpass project, part of a larger Fourmile Canyon Creek Flood Mitigation project, will build a bicycle and pedestrian underpass and help provide additional flood capacity in the future.

The 19th Street Multimodal Improvements project will help improve travel connections between Norwood and Sumac avenues.

  1. Community Engagement

    2017-2019

  2. Design

    2020-2022

  3. Build

    2023-2024

Project Overview

Detour Map

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.

Construction Updates and Impacts

We are committed to sharing construction updates on this webpage. Construction impacts may change due to changing and unforeseen conditions. Major construction began in March 2024, and will last approximately two years. View the detour map.

Impacts to 19th Street between Sumac and Upland avenues

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 closed to travel starting Monday, March 25, 2024.
  • Sanitary sewer construction impacts.
    • Due to the flooding of deep excavations for the construction of the new sanitary sewer system, pumps and a generator will be operating 24/7 starting Monday, April 15 until Monday, May 17 as anticipated dates. The generator provides power for the pumps being used to de-water the construction area. These generators are considered “whisper quiet” generators, and the contractor is performing noise decibel testing per City of Boulder Revised Code 9-5-3.

Per City of Boulder Revised Code 9-5-3, noise levels of 55 decibels are allowed between 5-11 p.m., and 50 decibels are allowed between 11 p.m. to 7 a.m. The results of the first sound testing of the generators completed on the evening of Tuesday, April 16, were the following:

  • 25’ away from the generator = 45.1– 50.5 decibels.
  • Nearest property line to the generator = 46 - 47 decibels.
  • At the property line of the western most residents on Tamarack = 31.5-36.1 decibels.
  • At the intersection of 19th and Upland = 30.5 decibels.
  • In instances when noise is anticipated to exceed the allowable levels per City of Boulder Revised Code 9-5-3, a noise variance will be issued by the city project manager. These instances will occur on a case-by-case and as needed basis as determined by the city project manager

Impacts to 19th Street between Sumac and Norwood avenues

Travelers can also expect impacts between Norwood Avenue and Sumac Avenue:

  • From June 5-21, the southbound RTD stop at Norwood Avenue must close to construct of the new curb/gutter, sidewalk and bus stop. Once the new stop is constructed, it will reopen. These are anticipated dates and may change. Check RTD schedules for updates.
  • Single lane closures where work is occurring. However, 19th Street will remain open to northbound and southbound travel throughout construction between Norwood Avenue and Sumac Avenue. Northbound 19th Street will remain closed between Sumac Avenue and Upland Avenue for the duration of the 19th Street and Fourmile Canyon Creek Underpass project.
  • Pedestrian and bike detours.
  • Delays when traveling in the area.

For updates, view the city's Cone Zones map.

19th Street and Fourmile Canyon Creek Underpass Project

Overview

Along with flood mitigation, the 19th Street and Fourmile Canyon Creek Underpass 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 and Upland avenues; 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. Construction began in 2024.

19th Street Multimodal Improvements Project

Overview

19th Street from Norwood to Sumac avenues is an important multimodal travel corridor in north Boulder. This project will help improve connections for all travel modes by constructing a new sidewalk and completing missing sidewalk links, upgrading the on-street bike facility to a buffered bike lane, enhancing transit stops, installing curb and gutter, and installing speed cushions, which are similar to speed bumps.

Construction on this project began in April 2024, with light construction activities with the contractor potholing existing utilities.

Project Improvements

From Norwood Avenue to Sumac Avenue on both the east and west sides of 19th Street, the 19th Street Multimodal Project will:

  • Install continuous sidewalks and curb & gutter on both sides of 19th Street from Norwood to Sumac avenues.
  • Convert the existing bikeable shoulders to a buffered bike lane facility.
    • Note: On-street parking will not be permitted with the transition from a bikeable shoulder to a bicycle lane with the addition of a curb and gutter.
  • Upgrade or install pedestrian curb ramps.
  • Plant new landscaping and trees to replace trees that will be removed in conjunction with this project.
  • Install a new storm sewer pipe and drainage inlets from Sumac Avenue to Wonderland Creek.
  • Replace the existing Wonderland Creek culvert with a 24-foot-wide by 5-foot-high culvert to meet floodplain development permit requirements.
  • Improve the bus stop.
  • Install traffic calming through "speed cushions" to reduce vehicle travel speeds while accommodating emergency response vehicles.
  • Reduce the posted speed limit from 30 mph to 25 mph.
  • Install enhanced pedestrian crossings where city guidelines identify them to be appropriate. All enhanced crossings installed through the project will include adequate street lighting and signage (State Law — Yield to Pedestrian).

From Sumac Avenue to Yarmouth Avenue:

  • Plan for future multimodal improvements, to be constructed once funding becomes available.

As part of a separate effort, in coordination with city staff, Xcel completed undergrounding of Xcel overhead utilities from Norwood to Upland avenues.

Summer 2022 Video Update

Project Background

19th Street from Norwood to Sumac avenues is an important multimodal travel corridor in north Boulder. Currently, there is an on-street bikeable shoulder and an existing sidewalk on the east side. These were constructed in the 1990s, but the sidewalk does not meet current city design standards. The on-street bikeable shoulder ends at Violet Avenue and is then a designated bike route from Violet Avenue north to Yarmouth Avenue. On the west side of 19th Street, the sidewalk is not continuous from Yarmouth to Norwood avenues.

19th Street from Norwood to Yarmouth avenues has been given a high priority on the city's Missing Sidewalk Links program. The Missing Sidewalk Links program identifies, prioritizes and constructs missing sidewalk segments to provide a continuous pedestrian network and ensure a safe walking environment.

In 2014, the city submitted an application for federal funding to construct a 5-foot-wide sidewalk, install curb and gutter on the east side and complete the missing sidewalk links on the west side of this corridor. The project received funding from the Colorado Department of Transportation (CDOT) Transportation Alternatives Program (TAP) and the Federal Highway Administration's Safe Routes to School grant program for the estimated project costs.

The city is also planning improvements along Fourmile Canyon Creek to improve safety and accessibility to Crest View Elementary School by completing an underpass at 19th Street and Fourmile Canyon Creek. Learn more on the Fourmile Canyon Creek webpage. The two project teams are coordinating efforts.

Further exploration of the Wonderland Creek floodplain was conducted from late fall 2018 through summer 2019 to understand expectations for achieving the floodplain development permit requirements. Two additional alternatives were included in the project's Community and Environmental Assessment Process (CEAP) to meet the identified facility type for 19th Street through the Low-Stress Walk and Bike Network Plan and to address Transportation Advisory Board feedback provided in August 2018. All design alternatives also now incorporate the features needed to meet floodplain mitigation requirements.

Selected Alternative: Concept 4

On Nov. 21, 2019, the project team hosted an open house, with 78 people in attendance, to share the five conceptual design alternatives being considered for the project and asked for the community’s feedback on a preferred alternative and reasons for that preference. There was a comment form available at the open house and online The goal was to learn which option was preferred so we can balance the needs of the community and meet the goals of the Transportation Master Plan. Your input was utilized as a final concept is selected.

Thanks to all who provided their input on the 19th Street Multimodal Improvement Project! We received a total of 58 completed comment forms. Whether you completed it at the open house on November 21, or provided it online, we appreciate your feedback.

Both the meeting comment forms and the online comment forms expressed a preference for Alternative 4 which includes a combination of attached and detached sidewalks and buffered bike lanes.

The 19th Street Selected Alternative: Concept 4. Long description in image caption.

View full image. This is a text alternative to the image: typical cross-section of the corridor, facing north. From left to right: 6-foot sidewalk varying from 0-2-foot colored concrete, 2-foot curb and gutter, 5-foot bike lane, 2-foot painted buffer, 10-foot travel lane in one direction, 10-foot travel lane in opposite direction, 2-foot painted buffer, 5-foot bike lane, 2-foot curb and gutter, 0-4-foot landscape strip transition, 6-foot sidewalk next to existing utilities.

Community and Environmental Assessment Process

During the city's annual capital improvements budgeting process, an interdepartmental team identified the 19th Street project to utilize the city’s Community and Environmental Assessment Process (CEAP). The CEAP is a formal review process to consider the impacts of public development projects. The purpose of the CEAP is to assess potential impacts of conceptual project alternatives in order to inform the selection and refinement of a recommended conceptual design alternative. The CEAP provides the opportunity to balance multiple community goals in the design of a capital project by assessing a project against the policies outlined in the Boulder Valley Comprehensive Plan, the Transportation Master Plan, departmental master plans, and sub-community or area plans (if applicable). The CEAP also ensures that environmental, social and fiscal impacts of projects are minimized and assures compliance with city policies, plans and regulations.

The final CEAP for the 19th Street project was reviewed and provided official recommendation by the City of Boulder CEAP Review Group, the city's Transportation Advisory Board and City Council.

Previous Community Engagement Events

  • The city held an open house on Thursday, April 19, 2018, for the public to view project alternatives, provide feedback and inform the selection of the preferred design. An online questionnaire was also open until May 14, 2018.
  • The project team attended the Community Cycles Advocacy Committee meeting on Feb. 5, 2018, to better understand their comments submitted through the "A Vision for 19th Street" report.
  • The project team participated in a WTS-Centennial Middle School Transit Study field trip with Centennial students on Jan. 23, 2018, to better understand their perception and use of transit. The field trip traveled from Centennial along Norwood Avenue to the transit stops at Norwood Avenue and 19th Street.
  • The project team hosted two site walks on Wednesday, Sept. 27, and Thursday, Sept. 28, 2017, to learn more about the project area and gather ideas for multimodal improvements.
  • The project was featured at the May 22, 2017, North Boulder Public Works Open House.
  • The project was included at a North Boulder Open House Meeting and Boulder Valley Comprehensive Plan (BVCP) Listening Session on Nov. 18, 2015. The project background and map were presented at the open house.

Frequently Asked Questions

Construction work hours for the 19th Street and Fourmile Canyon Creek Underpass project are typically between 8 a.m. and 5 p.m., Monday through Friday. However, this schedule is weather and task-dependent. Work may extend past 5 p.m. on a case-by-case basis with the city project manager's approval to ensure work tasks are completed in a safe and reasonable manner. Weekend work is also possible and will also be approved on a case- by-case basis by the city project manager. Notice of weekend work will be shared in advance by the Thursday prior via the project webpage.

Construction activities involve heavy equipment and machinery, and includes equipment and machinery needed for construction itself and for receiving deliveries to the job site. Community members should expect the use of heavy machinery during the typical work hours of 8 a.m. and 5 p.m., and when evening and weekend work has been approved by the city’s project manager. Additionally, neighbors should anticipate construction crews on the job site before 8 a.m. to hold safety meetings and prepare for the day's work. Independent, third-party trucking companies may arrive to the job site prior to 8 a.m. for deliveries, but will be instructed to wait until 8 a.m. to make their deliveries.

The Topaz Drive and Garnet Lane intersection has been closed to through traffic since the late 2000s in coordination between the City of Boulder and Boulder County (north of the intersection on Garnet is city jurisdiction, while south of the intersection on Garnet and Topaz is County jurisdiction). The city and County have decided to not open the intersection full-time to vehicles during construction due to costs associated with opening the intersection and limited benefits to traffic operations that would result.

However, the city has been approved to allow vehicles through the intersection with flaggers during the most impactful construction activities at the 19th Street and Riverside intersection during the 19th Street Multimodal Improvements project. More information about when this will occur will be shared on the project webpage.

The new underpass will allow students, families, and neighbors walking and biking to cross 19th Street completely separate from vehicle traffic, to access Crest View Elementary, Crestview Park, and other destinations to the east and west. New LED lighting will also be installed in the underpass and will stay on 24/7 to prevent illicit activities.

If, at any time, a community member believes there is an immediate threat to his/her/their safety or the safety of another person, we ask they call 9-1-1. A police officer will respond and take appropriate action. If a community member sees something that is concerning but not necessarily threatening, we encourage use of the 303-441-3333 police line, which is the city’s non-emergency phone number.