1. Plan

  2. Design

  3. Build

  4. Complete

Project Overview

28th Street is a state highway and a gateway to Boulder for employees, visitors, students, and residents. Corridor planning beginning in the early 2000’s, with a cutting-edge Complete Streets design which has since evolved to sync with other regional projects and the community’s current and future transportation needs.

Project Update

Once the 28th Street Improvements Project (Iris to Canyon) is completed, 28th Street from Baseline Road to Iris Avenue will be transformed into a multimodal corridor with a consistent design that delivers transportation, safety, aesthetic and economic enhancements.

28 St projects timeline


  • New Gateway with “Smart” Aesthetics
    28th Street is transforming into an attractive and appealing gateway that combines functional art, water-wise landscaping, and improved signage and landmarks.
  • Improved Transportation (Complete Streets)
    The multimodal transportation system increases safety to better accommodate travel for pedestrians, bicyclists, transit riders and drivers.
  • Expanded Travel Options
    The improvements provide roadway enhancements, better lighting, improved transit stops, and expanded bus services, bike lanes, sidewalks, and multi-use paths.
  • Retaining Wall with "Strata Variations"
    The retaining wall between Colorado Avenue and Taft Drive was built to stabilize the hillside and the "Strata Variations" public art was incorporated into the retaining wall.
  • Water-wise Landscaping
    Drought-resistant landscaping such as fertile grasses, shrubbery and trees requires little maintenance. The new irrigation system and wood mulch dramatically reduce water loss, surface runoff and weed growth. This system is designed to allow the city to selectively irrigate portions of the landscaping in possible drought conditions.
  • Regional Connections
    28th Street links CU, the Twenty Ninth Street retail district, the Boulder Junction area, local and regional transit routes, bus transit superstops, and FasTracks. The improvements strengthen multimodal travel throughout the region.
  • Economic Vitality
    The new 28th Street encourages private investments by improving access to businesses and adding value to existing ventures such as the Twenty Ninth Street retail district.
    The Boulder Convention & Visitors Bureau has put up colorful banners to encourage people to shop, dine and enjoy their time in our city. CU’s 28th Street Landscape Development Master Plan calls for enhancements on its eastern boundary, which include new outdoor basketball courts with sunken bleacher seating and possibly flower gardens.
  • Leveraged Funds
    More than 50 percent of the funding for the south section improvements came from state and federal sources and the rest came from the city’s transportation fund.
    The upcoming improvements along the Arapahoe Avenue to Valmont Road section of 28th Street is a combination of Capital Improvement Bond funding and city transportation funding. The improvements on 28 th Street/US 36 (Iris-Yarmouth) are a combination of federal and city transportation funding.

Canyon Blvd to Iris Avenue

This is the final segment of 28th street slated to receive improvements as part of this corridor wide improvements effort. The funding impetus for this project is founded in the corridor’s status as a primary state highway through Boulder, its status as a high crash corridor, the desire to increase the safety and presence of bicycle and pedestrian facilities here and the evolving vision for transit along this corridor.

The following improvements will be constructed along this segment:

  • a bus/bike/right-turn only lane (third outside lane added) in each direction along 28th Street
    • Left-turn lanes have already been added on 28th Street at the intersections of Pearl Street, Valmont Road, and Iris Avenue.
  • bus bay design to accomodate future SH-119 BRT service
  • complete gaps in the existing multi-use path by constructing ten-foot wide concrete paths with raised driveway crossings
  • install colored (green/red) conflict markings where warranted
  • install landscape buffers between the street and the multi-use paths
  • install street trees throughout the project length
  • replace traffic signals on 28th Street at Mapleton Avenue and Glenwood Drive
  • storm drainage upgrades and utility relocations

A key component and goal for this project is to maintain the continuity of corridor-wide design in keeping with the design of segments to the north and south. Foundational decisions were made during preliminary design (with stakeholder input) including the consistency of travel lane widths (all 11-feet), 10-foot multi-use paths (per city standards) and 8-foot landscaping strips. Additionally, the locations of transit stops were solidified at this time.

Draft Project Renderings:

SH 119 Project Integration

The constructed improvements will sync with the regional State Highway 119 Bus Rapid Transit (BRT) Project, which will include the addition of a managed/express lane and construction of a paved bikeway (view the route here) from Boulder to Longmont. BRT stations will be installed at Iris, Valmont, Pearl and Canyon in conjunction with the 28th Street Improvements Project.

This BRT project is spearheaded by a coalition comprised of the City of Boulder, City of Longmont, Boulder County and Commuting Solutions. Also involved in the planning and process are RTD, CDOT, High Performance Transportation Enterprise (HPTE) and the local area chambers.


These improvements have been funded with a number of sources, including city transportation funds, state transportation funds, federal transportation funds and the 2011 voter-approved Capital Improvement Bond.

Completed Projects

28th St completed projects map

Northern Section (Iris Avenue to Valmont Road)

In 2008 and 2009, safety improvements were made at the intersections of Iris and Valmont. Additionally, the Diagonal Highway Project (28th - Independence), completed in 2016, provided key connections to the 28th Street corridor.

Middle Section (Valmont Road to Arapahoe Avenue)

Multimodal improvements included a project to improve the center medians between Arapahoe and Walnut (2006), intersection improvements at Pearl Parkway (2007), new sections of multi-use path along 28th Street between Arapahoe Avenue and Spruce Street (2014) and a shared bus/bike/right-turn lane and new multi-use path along the east side of 28th Street between Pearl Street and Valmont Road.

South Section (Arapahoe Avenue to Baseline Road)

Construction of the south section between Baseline Road and Arapahoe Avenue was completed in phases. Phases one and two were completed between 2003-2006 and included new bike lanes, transit stops, improved roadway lighting, and construction of a sidewalk on the east side of the 28th Street Frontage Road. Phase three was completed by 2010 and included construction of a multi-use path along the west side of 28th Street between Canyon and Baseline.

Related plans:

28th Street Frontage Road Transportation Connections Plan

Additional Project Work on North 28th Street

Iris to Yarmouth Avenues

A new 10-foot-wide multi-use path along the west side of 28th Street between Iris Avenue and Fourmile Canyon Creek, pedestrian and bicycle bridge over Fourmile Canyon Creek and continuous on-street bike facility on 28th Street between Iris and Yarmouth avenues was completed in 2015. These improvements provide an improved multimodal transportation system with expanded travel options for students and their families, staff, residents, employees and others traveling through the area. Public art at the bridge and southbound bus stop beautify this bicycle and pedestrian improvement. Funding for this section of 28th Street was provided through a Federal Transportation Improvement Program (TIP) grant and city Transportation funds.

Final Design Concept for the 28th Street Improvements (Iris to Yarmouth Avenues)

The 28th Street (Iris to Yarmouth Avenues) Bicycle and Pedestrian Improvements was reviewed through the city's Community and Environmental Assessment Process (CEAP). A public hearing was held at the May 13, 2013 Transportation Advisory Board (TAB) meeting and the board recommended approval of the project CEAP and recommended design options. The CEAP document was forwarded to City Council for potential call-up by July 16, 2013. After not being called up, the project proceeded toward final design.

Violet Avenue & US 36 Intersection Re-alignment

To improve safety at the intersection of Violet Avenue and US 36, a popular route for drivers and on-street cyclists with a history of fatal collisions--the intersection was reconstructed so that Violet Avenue meets US-36 at a right angle. This improves sightlines and visibility for both drivers and cyclists. A five foot wide sidewalk on the south side of Violet Avenue from 23rd Street to US-36 and a pedestrian median at US-36 was also installed through this project. In addition to the re-alignment and pedestrian improvements, this project closed the section of Violet Avenue from 26th to 28th streets to simplify and further improve the safety of this intersection.