I-25: Speer & 23rd Bridge & Interchange Project

About the Study

This project will replace the bridges at Speer Boulevard and 23rd Avenue over Interstate 25 in Denver. Beyond this core focus of the project, CDOT is assessing the needs and opportunities to include additional improvements to the interchange system and how to support broader goals for the I-25 mainline and those of the surrounding community.

This is the first project resulting from the I-25 Central Planning and Environmental Linkages (PEL) study, which was completed in 2019. This project is using details from existing conditions and proposed alternatives from the I-25 Central PEL study to develop an effective solution that not only remedies current problems, but will align with future vision for the I-25 corridor and the surrounding area and community.

The bridges for Speer Boulevard and 23rd Avenue are the lowest clearance on all of I-25 — Wyoming through New Mexico

23rd and Speer Project Area

Study Schedule

Summer – Fall 2021: Identify Corridor Needs (Supplemental Data Collection and Analysis)

Fall 2021 – Spring 2022: Alternative Refinement and Evaluation

Winter 2021-Fall 2022: Environmental Analysis and Documentation

Summer 2022 - Winter 2023: Preliminary Design 


Summer 2021: Purpose and Need

Winter 2021: Public Meeting 1

Spring 2023: Preferred Alternative

The project launched in Spring 2021. We have convened our project management and technical teams, including the City and County of Denver, to ensure good communication and collaboration on the project. We are currently developing the logical termini (endpoints of the project), our data collection methodologies and the draft purpose and need statement (which is a requirement for the Federal Highway Administration).  

All of this work will inform the scope of the project, essentially answering the question "will this project solely replace the bridges or will it include broader improvements?"

Once we have determined the scope of the project, the project team will finalize the purpose and need statement as well as the alternatives that this project will consider. Those alternatives will then be evaluated to understand how each alternative performs regarding meeting the purpose and need, operations, community and environmental impacts and costs of the project.

Identify Corridor Needs (Data Collection and Analysis)
Existing conditions data, such as the condition of the highway and bridges, and the locations of rail, bicycle and pedestrian facilities and transit was collected during the PEL. Supplemental data will be collected for this project, which may include environmental resource information and traffic and safety data. This information will help refine the needs of the corridor and the development of the purpose and need.

Alternatives Refinement and Evaluation
Building on the recommended alternatives from the PEL, alternatives will be refined according to the identified needs and evaluated to determine the preferred alternative for the project.

Environmental Analysis and Documentation (NEPA)
Once a preferred alternative is identified, it will be analyzed for the potential to cause environmental effects. These effects will be documented in an Environmental Assessment.

Public and Stakeholder Involvement
The project is working with community members and stakeholders to ensure that community interests and concerns are understood and linked to project decision-making. Engagement activities will occur through the duration of the project and will include:

  • Citizen’s working group
  • Close communication with the City of Denver
  • Virtual and in-person activities
  • Public meetings

Core Outcome of the Project:

  • Replace structurally-deficient and low-clearance bridges at 23rd Avenue and Speer Boulevard

Other Considerations:

  • Reconfigure interchanges at Speer Boulevard and 23rd Avenue
    • Improve pedestrian and bike safety, and cross-connectivity over I-25
  • Interconnect Speer Boulevard and 23rd Avenue with a frontage road system
    • Improve mainline I-25 flow and reducing weaving congestion
    • Improve commuter and special-event access to downtown, Pepsi Center, Mile High Stadium, and future developments.
  • Create an attractive and functional gateway to downtown Denver