I-25: Speer & 23rd Bridge & Interchange Project | Study Phase

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 a future vision for the I-25 corridor and the surrounding area and community.

Note: The crossings do not provide adequate vertical clearance over I-25 and have experienced multiple vehicular impacts resulting in damaged girders and exposed primary reinforcing. 

Project Area

The study area map shows the bridges over I-25 at 23rd Ave. and at Speer Boulevard and the interchange ramps at both locations are the roadway elements being studied for improvements.
This study area map shows the bridges over I-25 at 23rd Ave. and at Speer Boulevard and the interchange ramps at both locations are the roadway elements being studied for improvements. 

Study Schedule

  • 2023: Data collection and preliminary alternatives development
  • Early 2024: Purpose and need developed, and initial screening
  • Mid-2024: Alternative refinement and secondary screening
  • Late 2024 to 2025: NEPA analysis and documentation, start of preliminary design
  • 2026 and Beyond: Identify construction delivery method, identify construction funds, and finish preliminary design

 Scope & Study Overview

CDOT launched the I-25: Speer & 23rd Bridge & Interchange Project during the Summer of 2021 to study and evaluate replacing the bridges that cross over I-25 in Central Denver. These bridges are near the end of their useful life and are often struck by trucks due to deficient vertical clearance. They are in need of replacement for the safety of all travelers.

This project seeks to:

  • Improve operations and safety for vehicles
  • Improve facilities for bikes and pedestrians

To ensure effective communication and collaboration, we have convened our project management and technical teams, including representatives from the City and County of Denver. Together, we have established the logical termini (endpoints of the project), developed data collection methodologies, and drafted a purpose and need statement, which is a requirement for the Federal Highway Administration.

 Next Steps

Finalizing Purpose and Need
The team will review any public input received and finalize the Purpose & Need Statement.

Screening and Refining Alternatives
The project team will combine technical evaluation and community input to screen out draft alternatives that do not sufficiently meet Purpose & Need and refine the remaining alternatives for more detailed evaluation.

Next Public Meeting

The next public meeting is planned for 2025. The public meeting will cover the following items:

  • Recap Initial Alternatives and Public Involvement
  • Share results of Alternatives Evaluation and Refinements
  • Show alternative(s) that are recommended to advance into NEPA, based on technical and public input
  • Show bike and pedestrian facilities for recommended alternative(s)

 Project Delivery

Identify Corridor Needs (Data Collection and Analysis)
Existing conditions data, such as the condition of the highway and bridges or the locations of rail, bicycle and pedestrian facilities, and transit, were collected during the I-25 Central PEL. Supplemental data has been collected for this project, which includes environmental resource information and traffic and safety data. This information helped 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 and human effects. These effects will be documented through the NEPA process.

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:

  • Community-based Stakeholder Group
  • Close communication with the City of Denver
  • Virtual and in-person activities
  • Public meetings
  • E-notification updates (Sign up in the "Stay Informed" section)

 Project Outcomes

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
    • Improve vehicular safety and operation on I-25