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Baseline Road Underpass Project

Baseline Road Underpass Project

The Baseline Road Underpass Project is Complete!

Over 125 people came out to show their support for this important transportation safety improvement.  



Project Overview

Baseline Underpass Project Map

The section of Baseline Road between Broadway (SH 93) and 27 th Way is an important corridor for the Boulder community and the University of Colorado at Boulder (CU). An underpass at this location has been planned since the city’s first Transportation Master Plan (1989). Since that time, the city installed a series of interim pedestrian crossing treatments until an underpass could be built to address the significant number of motor vehicle collisions with bicyclists and pedestrians that occur there.

The construction of that underpass began in 2016 and was completed in 2017, providing a safer crossing of Baseline Road for bicyclists, pedestrians and drivers, reducing conflicts between vehicles and bicyclists and pedestrians, and improving connectivity in the project area. 

The project connected the underpass to existing sidewalks, multi-use paths and on-street bicycle lanes, reconstructed medians and resurfaced the street with asphalt. Additionally, a multi-use path was constructed on the east side of Broadway from Baseline Road to the Basemar Shopping Center entrance. Bicycle parking, a relocated B-Cycle station, landscaping and public art ("Triangulation") were also be incorporated into the project improvements.

More about the "Triangulation" Public Art

Baseline Road is the control line for the 40th Parallel originally surveyed by the U.S. Government in 1859. The survey crew, led by Jarret Todd and James Withrow, navigated over 345 miles in 55 days to the base of the Rocky Mountains, then the eastern side of Utah Territory. "Triangulation" highlights Baseline Road, the original 40th Parallel, in a map of North America, and features a prism tower and triangle stone columns at the underpass approaches and fractal pattern within the underpass on its walls. 

Project Scope

The project constructed an underpass at Baseline Road between Broadway and 27 th Way and also:

  • Provided a grade separated crossing of Baseline Road
  • Provided connections to the existing sidewalks, multi-use path and bicycle lanes on Baseline Road
  • Constructed a multi-use path on the east side of Broadway from Baseline Road to south of the Basemar Shopping Center entrance which connects to an existing multi-use path that links to the Skunk Creek multiuse path
  • Reconstructed the median on Baseline Road
  • Overlaid asphalt on Baseline Road from Broadway to 27 th Way
  • Reconstructed and enhanced the existing transit stop
  • Relocated the B-Cycle station to be closer to the reconstructed transit stop
  • Installed underpass lighting, landscaping and other urban designs
  • Installed public art pdf


The project began construction in May, 2016 and was completed on June 14, 2017.  

Public Involvement and Community and Environmental Assessment Process (CEAP)

Previous Public Events


This project was reviewed through the city's Community and Environmental Assessment Process (CEAP) and Option B pdf was selected as the preferred underpass design option and supported by the Transportation Advisory Board (May 12, 2014) and City Council (June 17, 2014). 


The project budget of $5.4 million came from the following sources:

  • $554,000 of City of Boulder transportation funds;
  • $4.046 million of Federal Highway Administration funds; and
  • $800,000 in Colorado Department of Transportation funds.


Contact Noreen Walsh, Transportation Division, at 303-441-4301. 

Or Comment on the Baseline Road Underpass--You don't need to register, and comments can be submitted through the "Make a Service Request for Transportation Projects" button.

Baseline Road Existing Conditions

Baseline Road Underpass Between Broadway and 27th Way (Planning/Design)Baseline Road Underpass Between Broadway and 27th Way (Planning/Design)Baseline Road Underpass Between Broadway and 27th Way (Planning/Design)Baseline Road Underpass Between Broadway and 27th Way (Planning/Design)Baseline Road Underpass Between Broadway and 27th Way (Planning/Design)Baseline Road Underpass Between Broadway and 27th Way (Planning/Design)Baseline Road Underpass Between Broadway and 27th Way (Planning/Design)

See all related photos in the Photo Gallery

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