Program Updates

Supplemental Environmental Impact Statement

The Draft Supplemental Environmental Impact Statement (SEIS) is expected later this year.

Following the release of the Draft SEIS, a 60-day public comment period will open.

This page will provide the information necessary to learn about the process and how to review the document, as well as when and where to find opportunities to provide feedback.


Cover of the SEIS document showing a truck crossing the bridge.

What is the Draft SEIS?

This comprehensive document is a federal requirement of the National Environmental Policy Act (NEPA), which is an opportunity and responsibility for the program to analyze the potential impacts and benefits of the Modified Locally Preferred Alternative (LPA) in comparison to a No-Build alternative. Publishing this document kicks off a crucial period for the community to weigh in on the program’s direction. This input will help shape the solution that advances to the Final SEIS as the program works to replace the aging Interstate Bridge with a safer, more resilient multimodal corridor that is responsive to the needs of travelers and communities with our region for decades to come.  

What should you expect to see in the Draft SEIS?

The IBR program studied the Modified LPA to understand its potential benefits and effects on the community and environment compared with the No-Build Alternative. The Modified LPA is not the program's final design, but identifies key foundational design elements. The Draft SEIS presents the Modified LPA's major design elements and the potential associated benefits, impacts, and proposed mitigation measures. Additional refinements and adjustments will be made to the proposed program investments in response to public comments and other design considerations. The No-Build Alternative is analyzed and compared to the Modified LPA to understand what would happen if nothing is built.

What does the Modified LPA include?

  • A new bridge built west of the existing bridge.
  • Improvements to seven interchanges, north and south of the Columbia River, as well as related enhancements to the local street network.
  • Extension of light rail from the Expo Center in Portland to Evergreen Boulevard in Vancouver, along with associated transit improvements such as transit stations.
  • One auxiliary lane in each direction and safety shoulders on the bridge.
  • A variety of improvements for people who walk, bike and roll throughout the program area.
  • Variable rate tolling for motorists using the river crossing as a demand management and financing tool.

There are also several design options the program is studying:   

  • Bridge configurations 
  • A second auxiliary lane 
  • Alignment of I-5 in downtown Vancouver 
  • Freeway interchanges   
  • Park and rides at transit locations  

Draft SEIS Chapters

The document is broken down into chapters and sections by topic area. A list of chapters correlating to the areas of analysis can be viewed below. The Summary document will also be made available in various languages and other forms to ensure accessibility for all groups.

  • Summary
  • Front Matter
  • Ch 1. Purpose & Need
  • Ch 2. Description of Alternatives
  • Ch 3. Existing Conditions and Environmental Consequences
  • 3.1 Transportation
  • 3.2 Navigation
  • 3.3 Acquisitions & Displacements
  • 3.4 Land Use & Economic Activity
  • 3.5 Neighborhoods & Equity
  • 3.6 Public Service & Utilities
  • 3.7 Parks & Recreation
  • 3.8 Cultural Resources
  • 3.9 Visual Quality
  • 3.0 Air Quality
  • 3.11 Noise & Vibration
  • 3.12 Energy
  • 3.13 Electric & Magnetic Fields
  • 3.14 Water Quality & Hydrology
  • 3.15 Wetlands and Waters
  • 3.16 Ecosystems
  • 3.17 Geology & Groundwater
  • 3.18 Hazardous Materials
  • 3.19 Climate Change
  • 3.20 Environmental Justice
  • 3.21 Section 6(f) & Federal Lands to Parks
  • 3.22 Aviation
  • 3.23 Cumulative Effects
  • Ch 4. Financial Analysis
  • Ch 5. Section 4(f) Evaluation


  • A. Agency & Tribal Coordination
  • B. Public Involvement
  • C. Concept Design Drawings
  • D. Design Option Development and Screening Report
  • E. References
  • F. List of Preparers
  • G. List of Draft SEIS Recipients
  • H. List of Technical Reports
  • I. Glossary
  • J. Index

What opportunities will there be for review and input? 

The public plays an important role providing feedback on proposed investments and design options, the potential impacts and benefits identified, and potential mitigation options. Following the release of the Draft SEIS, a 60-day public comment period will open for the program to receive input from the public. During this 60-day window, the program will offer many opportunities to provide feedback as part of the public comment period. That includes joining a public hearing to provide testimony or submitting your comment in non-public settings by using a web form, sending an email, writing a letter or leaving a voicemail. Language interpretation and ASL services will be available to ensure accessibility for all community members.   

How you can provide comment

Following the release of the Draft SEIS, a 60-day public comment period will open for the program to receive input from the public. During this window, the program provide opportunities for comment. Your feedback is important in shaping a solution.

You will be able to provide comments in the following ways:

Submit a comment online   Attend a public hearing   Send an email  Call the hotline

The program will continue adding opportunities to learn more about what is being studied and what to expect in the Draft SEIS throughout the coming months. Additional information on the multiple ways to provide feedback during the public comment period will be shared and available on this page as the publication date approaches.  

A summary of comments received will be shared following the public comment period. All public comments will be recorded and a response will be documented in the Final SEIS. Responses will include any changes, updates, and new information added based on those comments. 

The public will be able to review a hard copy of the Draft SEIS Executive Summary at the IBR office and the full document and technical reports and appendices will be available digitally via a searchable PDF. 

Further reading on the federal environmental review process

Council on Environmental Quality’s NEPA webpage
FHWA’s Environmental Review Toolkit
FTA’s Environmental Review Process

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