How the CO 119 Diagonal Is Becoming a Vision of Sustainable, Safe Transportation

The future of northwest Colorado is bright, with plans to safely accommodate many more people who will need new ways to get around.

In 2014, Boulder County, the Colorado Department of Transportation (CDOT), and the Regional Transportation District (RTD) commissioned the Northwest Area Mobility Study (NAMS) and the Multi-Modal Planning and Environmental Linkages Study (PEL) to create a forward-thinking vision of sustainable transportation to accommodate region’s anticipated rapid population growth.

What surfaced from the studies was urgency to prioritize greater mobility through multimodal travel options for pedestrians, cyclists and motorists, and to provide Bus Rapid Transit (BRT) along CO 119—the Diagonal Highway that runs from Longmont to Boulder.

Many projects have been planned to meet such ambitious sustainable transportation goals! The plans and designs underway include user-friendly connections between the commuter bikeway, improved pedestrian crossings, bus queue bypass lanes, BRT stations, and Park-n-Rides.

Baked into all plans to transform the Diagonal Highway is an environmentally friendly mission to reduce climate change and improve air quality, provide modernized safety features, and allow for greater accessibility and equity.

One project, currently in the design phase, is the CO 119 Safety and Mobility Improvements Project, a joint project by CDOT and RTD. To mitigate the predicted escalation of traffic congestion and delays, curtail tailpipe emissions and potentially reduce crashes, the project aims to expand safe transportation options.

The safety and mobility improvements include:

  • BRT improvements at Jay Road, 63rd, CO 52 and Niwot Rd.
  • New signage, striping, and improved signal timing at all pedestrian crossings.
  • Signal timing adjustments at key intersections (Jay Road, 63rd Street, CO 52, Niwot Road, and Airport Road).
  • Physically reconfiguring the CO 52 intersection to improve safety and to accommodate new Bus Rapid Transit (BRT) stations and Boulder County’s Commuter Bikeway between the northbound and southbound roadways.
  • Changing access at Airport Road and CO 119 to reduce crashes and to improve safety and traffic flow.
  • A separate project to improve the Hover Street intersection

Bringing BRT to the Diagonal

The CO 119 Highway vision for multimodal travel options also includes BRT service from Boulder to Longmont. A Traffic Alternatives Analysis Study recommended implementing queue bypass lanes as a bus priority asset along the Diagonal. Queue bypass lanes, or queue jumps, are a popular BRT tool worldwide. The study also determined that building out BRT service with queue bypass lanes will shorten bus travel times by nearly 50%.

Building on ideas incorporated with public input, the CO 119 Safety and Mobility Improvements Project is designed to work in conjunction with these other projects:

Design for the CO 119 Safety and Mobility Improvements Project is ongoing with construction anticipated to start in 2024.

CO 119 Bikeway Project

The NAMS and PEL studies noted above also reflected a strong desire by stakeholders to improve bicycle connectivity between Boulder and Longmont, and the growing popularity of Ebikes will contribute to the need for more bikeways.

Boulder County is taking the lead on designing a separated, safe, hard-surface bikeway to guide riders between Boulder and Longmont along the Diagonal Highway’s median. This is the CO 119 Commuter Bikeway Design Project.

The bikeway will provide easy access to transit stations and will connect riders to important destinations along the corridor and bike networks in downtown Boulder, the University of Colorado at Boulder campus, South Boulder, and downtown Longmont. You can learn more and visualize how these ideas for greater sustainable transportation are becoming a reality! CDOT, RTD, and Boulder County hosted a virtual meeting on June 27, 2022 to showcase preliminary design plans for the CO 119 Safety and Mobility Improvements Project and the CO 119 Commuter Bikeway Design Project. See the designs in a recording of the meeting here.

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Commuting Solutions
CO 119 Membership Meeting

April 24, 2024  | 8:00 – 9:30 a.m.
At Hampton Inn & Suites, Boulder North