Frequently Asked Questions

I-25 Central PEL Process

What is a Planning and Environmental Linkages (PEL) Study?

A Planning and Environmental Linkages study is a process typically used to identify transportation issues and environmental concerns in a large corridor or a specific location. It is generally conducted before any project construction funding is identified, and before specific problems and solutions are known. At a high-level, a PEL study:

  • Reviews existing environmental resources and examines the existing infrastructure and congestion conditions;
  • Identifies corridor needs (i.e. safety, congestion);
  • Defines and evaluates potential improvements;
  • Identifies possible impacts from proposed alternatives; and
  • Develops a vision and implementation plan for priorities large and small.

At their completion, PEL studies should be able to link planning to environmental issues and result in useful information that can be carried forward into the National Environmental Policy Act (NEPA) process.

Read more information about CDOT’s Planning and Environmental Linkages Program.

What is the purpose of I-25 Central PEL?

The I-25 Central PEL study is examining Interstate 25 (I-25) between Santa Fe Drive/US 85 and 20th Street in Denver. The purpose of the recommended transportation improvements is to reduce congestion and improve safety and travel-time reliability for the movement of people and goods. The improvements will also consider access to and from I-25 as well as connectivity across I-25 for bicycles, pedestrians, transit and local traffic. See the Draft Purpose and Need statement 

What are the Goals of the Project?

In addition to the core purpose of the project, numerous goals also have been identified. These include:

  1. Investigate opportunities to improve mainline geometry and design to meet current standards and address substandard:
    • Stopping-sight distance
    • Clear zones
    • Narrow lane widths and narrow shoulder widths
  2. Investigate opportunities to use and/or not preclude emerging technologies to improve the safety, capacity, and management of mainline operations
  3. Provide efficient access to major parallel routes and corridor destinations
  4. Consider the impacts and benefits of proposed improvements on the local network
  5. Improve connectivity across I-25 and the South Platte River for all modes
  6. Consider the impacts of adjacent high-density redevelopment and the related potential changes in travel demand on I-25
  7. Consider the impact of congestion improvements on southbound I-25 in relation to improved operation for southbound RTD buses
  8.  Consider the impacts and benefits on freight movement in the corridor
  9. Consider the ability of improvements to the mainline and local network to improve person-trip connectivity
  10. Consider the effects of improvements on the South Platte River and the surrounding communities
  11. Consider the effects of expanded right of way on adjacent land uses
  12. Consider the ability of improvements to provide community and environmental enhancements
  13. Consider the ability of improvements to support economic development opportunities in the metro Denver area

How are I-25 Central PEL alternatives being developed and evaluated?

An initial list of alternatives was developed through a series of brainstorming discussions and interviews with key project stakeholders, project team members, and representatives from the public including members of neighborhood organizations, local business owners and coalitions, non-profit organizations, and others.

The alternatives developed are being evaluated through a three-level process. Initial evaluation examined whether an alternative meets the project’s purpose and need. The second level of evaluation examined how well an alternative meets the project goals. The last level of evaluation will examine the detailed tradeoffs between alternatives and make final recommendations about which alternatives should be carried forward into the NEPA process.

Alternatives are eliminated from further consideration at any level of evaluation if they are determined to not meet the projects purpose and need, or if a fatal flaw in their design is identified. It should be noted, however, that just because an alternative is eliminated from consideration it does not mean that elements from that alternative could not be carried forward. Upon removal from consideration, alternatives will be examined and positive elements or concepts from the alternative could be combined into existing alternatives, or recompiled into new alternatives to be carried forward.

What is the I-25 Central PEL Schedule?

Are you working with any other agencies and considering their goals?

This study is highly collaborative. In addition to community organizations and local businesses, CDOT is working with the City and County of Denver; the Federal Highway Administration; RTD; and the Denver Regional Council of Governments. All of these groups provided input on this PEL’s purpose, needs, goals, and objectives which reflect the many different goals of the respective groups and agencies. Using the purpose, needs, goals, and objectives as the basis for the alternative’s evaluation process ensures that the outcomes of this study support and balance the overall missions and priorities of all project stakeholders.

Getting Involved

What are the opportunities for public and agency participation?

Understanding the ideas, perspectives and needs of stakeholders in the corridor area is critical to building broadly supported decisions and solutions. The I-25 Central PEL study has multiple ways to get involved and stay informed.

Stakeholder Focus Group
The stakeholder focus group (SFG), is a group of representatives from a wide range of local stakeholders throughout the corridor. This group includes people from neighborhood associations, businesses and business coalitions, and non-profit organizations. The SFG meets at key project milestones to review the work to-date and provide feedback to the project team. Key milestones for this project include:

  • Development of the project’s purpose and need;
  • Completion of the level 1 evaluation;
  • Completion of the level 2 evaluation; and
  • Completion of the level 3 evaluation

See the full list of the organizations that are a part of the I-25 Central SFG.

Public Open House
As part of the alternatives evaluation process, the I-25 Central project team hosted a public open house. This provided all interested persons the opportunity to learn more about the alternatives being evaluated, the initial results of the evaluation process, and ask questions directly to the project team. 

Download the materials from the Open House.

The I-25 Central Project Website
In addition to in-person engagement opportunities, current information about the project’s progress to-date as well as feedback opportunities are always available within this site. 

Are there real projects, or is this just another study?

There are several projects on I-25, from Santa Fe to 20th, which have been studied in the past and could proceed more quickly if funds were made available.

  • To the south, more than ten years ago the Valley Highway EIS studied and generated six projects, or “phases,” from Santa Fe to 6th Ave. The recently completed construction projects at Santa Fe and 6th Ave account for only half of the planned work. Remaining phases in this area, yet to be funded, include improvements to Alameda, an improved connection from Alameda to north I-25, railroad track realignment, and I-25 improvements from Alameda to 6th Ave
  • On the north side of the corridor, studies of the 23rd Ave and Speer bridges have already highlighted poor remaining structural life, deficient clearance for trucks, outdated access ramps, and poor bicycle/pedestrian connectivity.
    Each of these projects-in-development are included in this PEL study, for a holistic visioning of the future of I-25.

How can I see the results?

The final PEL study will be available in the Fall of 2019. However, you can get involved in the process before anything is decided. Project materials, including preliminary results and materials presented at public and stakeholder meetings, are available for download. These materials will also be presented in-person at the upcoming public open house. Interested persons can also register to receive the periodic project update email blast which provide information on the current progress of the PEL study.

Contact Us
  • [email protected]

  • 303.214.0852
    Leave a message and we'll get back to you within one business day.

  • Mail:
    Steve Sherman
    2829 W Howard Pl.
    Denver, CO 80204

  • Media Contact:
    Tamara Rollison
    [email protected]


Colorado: The Official State Web Portal