Highway 119 Bikeway Project

Due to COVID-19, the Community Planning & Permitting Department is conducting business and providing services virtually. Our physical office in Boulder is currently CLOSED to the public.

The Diagonal Highway 119 Bikeway Design Project

Conceptual rendering of SH 119 Bikeway

Conceptual rendering of the planned CO 119 Bikeway.


The vision for the Diagonal Highway CO 119 Bikeway Design Project is a safe, direct, accessible, and comfortable separated hard surface bikeway between Boulder and Longmont.

The bikeway will provide seamless connections with transit (BOLT, future bus rapid transit, and commuter rail) and connections to bike networks in downtown Boulder, CU, South Boulder, and downtown Longmont.

CO 119 Bikeway Design Survey

Encuesta para ciclovía CO 119

Virtual meeting on the CO 119 (the Diagonal) Bikeway Design, August 30, 2021

Boulder County’s Community Planning & Permitting Department and CDOT invited the public to a virtual meeting presentation on the CO Highway 119 Bikeway Project on August 30, 2021. Staff discussed the conceptual design of the bikeway and potential connections at the north and south ends of the project. Participants had an opportunity to ask questions and provide feedback on the design concepts at the meeting.

CO 119 Safety, Mobility and Bikeway Community Advisory Committee

Transportation inclusive planning groupIn August of 2021, Boulder County’s Community Planning & Permitting Department invited interested residents to apply to the new State Highway (CO) 119 Community Advisory Committee (the Diagonal Highway) that will help guide planning for the CO 119 Commuter Bikeway and CO 119 Safety and Mobility Improvement projects. The application period is now closed.

The County received more than 90 applications for the Community Advisory Committee. We are appreciative of so many people in the community wanting to be on the committee. It is going to take us some time to go through the applications and make selections. We will notify everyone who applied as soon as the selections are made.


The purpose of the committee is to give feedback on the design of both projects to fulfill the goals the of 1) optimize regional connectivity and mobility between and within Boulder and Longmont through multimodal improvements, and 2) develop a bikeway that is safe, direct, accessible, and comfortable with seamless connections to transit, neighborhoods, businesses, and existing paths.

Committee Seats

The CO 119 Community Advisory Committee will be comprised of 10 members:Spanish language community conversation

  1. Community member who resides or works in or near Longmont
  2. Community member who resides or works in or near Boulder
  3. Community member who resides or works in or near Niwot or Gunbarrel
  4. Business owner on or near the corridor that employs workers with transportation challenges
  5. Employee on or near the corridor who has transportation challenges commuting to work
  6. Cyclist who uses or crosses the corridor as part of their regular bike commute route
  7. Recreational cyclist
  8. Current public transit user along the corridor

Two additional seats will be filled with liaisons from the CO 119 Project Equity Advisory Committee.

Boulder County strives for diversity of race, gender, age, language, income, and ability for committee membership. The Committee will work in partnership with the Colorado Department of Transportation (CDOT) Region 4, and Regional Transportation District (RTD)and the new Equity Advisory Committee.

For more information, contact Alexandra Phillips at 303-441-4520 or aphillips@boudercounty.org.

In 2014, The Northwest Area Mobility Study (NAMS) was completed. The NAMS report includes a prioritized list of mobility improvements for the Northwest area of the Regional Transportation District’s (RTD) service area. CO 119 was identified as the top priority corridor for improving mobility in Boulder County and included recommendations for Bus Rapid Transit and a separated bike facility.

This collaborative effort included RTD, the Colorado Department of Transportation (CDOT), the Denver Regional Council of Governments (DRCOG) and the Northwest Area Stakeholders: 36 Commuting Solutions, City of Arvada, City of Boulder, Boulder County, City and County of Broomfield, City of Lafayette, City of Longmont, City of Louisville, North Area Transportation Alliance (NATA), Town of Superior, University of Colorado, and City of Westminster.

In 2019, a Planning and Environmental Linkages (PEL) report was completed which identified the multi-modal corridor vision for CO 119. This vision includes:

  • Bus Rapid Transit (including Park-n-Rides, new stations, Business and Transit lanes, Transit Signal Priority/queue jump lanes)
  • Intersection Improvements
  • BRT/Managed Lanes
  • Separated Bikeway

For more information please go to the Commuting Solutions website.

  • CO 119 Bikeway Concept Design Validation Memo (draft published August 2021). The purpose of the Design Validation is to review, evaluate, and refine the Conceptual Design with more precise project goals and design criteria as well as additional information such as land survey data and environmental information. These goals and design criteria include the following:
    • Use design criteria for higher speed users, considering bike commuters, athletic riders, and e-bikes
    • Maximize efficient connectivity to the corridor to attract use
    • Consider a wider tread or other treatments in areas of higher use
    • Minimize impacts to existing vegetation, waterways, and wetlands where possible
  • The Conceptual Design shows the basic alignment of the bikeway within CDOT right-of-way, general locations of grade separated, and at-grade crossings.

The preliminary design is a more in-depth study of the constraints and design issues that will help determine the best alignment for the bikeway. The preliminary design includes:

  • A complete on the ground field survey including topography. This will be important for designing a bikeway that does not flood in the rain.
  • Map of existing above ground and underground utilities, trees, culverts, irrigation ditches. This will show what needs to be moved, redesigned or needs to be worked around.
  • Environmental Data including:
    • wetland locations, if threatened or endangered wildlife species live or migrate through the project area.
    • Noxious weed inventory
    • If there are any hazardous materials in the corridor
    • Historic resources
  • Geotechnical information including soil sampling and groundwater measurements. This is important so the bikeway won’t sink or buckle and underpasses won’t flood
  • Traffic study: this is important to design safe at- grade crossings are safe and utilize features such as bicycle detection and rapid flashing beacons and pedestrian medians

Boulder County is working closely with CDOT, RTD, the Cities of Boulder and Longmont and Commuting Solutions so the bikeway and the Mobility Project and the PEL for CO 52 work seamlessly together for all travelers.

Map of SH 119 Bikeway Project's coordination with other projects along the main line of the SH 119 corridor

Project Coordinator

Boulder County Community Planning & Permitting
Stacey Proctor, 303-441-1107

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Community Planning & Permitting (formerly the Land Use Dept.)

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