• Study

I-5 Master Plan

Planning study news

In June 2026, WSDOT submitted an I-5 Project Status Update to the Legislature. The update outlined progress on the I-5 Master Plan to date, including development of the project vision and goals and the identification of current and future needs along the I-5 corridor. This update can be found in both the “Outcomes” and “Additional Resources” sections below.

Timeline
2022-2029
Status
In progress
Budget
In the 25-27 biennium, WSDOT received $11.75 million to continue to advance I-5 planning, including development of an I-5 Master Plan.

Purpose

Take the survey on our public engagement site (now live!) to shape how we travel today and tomorrow

The I-5 Master Plan is part of WSDOT’s Cascadia High-Speed Rail and I-5 Program to address the transportation needs of the growing Cascadia megaregion. The integrated Cascadia High-Speed Rail and I-5 Program allows us to look holistically at highway, rail and other travel options.

In spring 2022, the Legislature initiated the Move Ahead Washington funding package, providing funding for initial studies on the future of the I-5 system and establishing the framework for a border-to-border I-5 Master Plan focused on near- and long-term improvements. WSDOT began initial planning and data collection and launched the I-5 Master Plan process in 2024.

I-5 Master Plan

The I-5 Master Plan Project is developing an actionable master plan for the I-5 system in Washington state. This plan will identify, prioritize and guide investments to address both near- and long-term needs. The I-5 Master Plan will also identify opportunities for innovation, including leveraging new technologies and integration with other transportation modes. The I-5 Master Plan recommendations will be guided by the following vision for the corridor:

“I-5 is a safe, reliable, and resilient system that provides accessibility and multimodal travel options for all and supports regional and statewide economic vitality.”

I-5 Master Plan study area includes all of I-5 in Washington state, from the U.S.-Canada international border to the Washington-Oregon border.
Stay informed by subscribing to our email updates

Project description

The I-5 Master Plan is a long-term, high-level effort to address critical needs and maximize opportunities along the I-5 corridor in Washington state. The plan takes a systemwide approach to identify and prioritize programs, strategies, studies and projects for implementation and funding across key focus areas, including safety, mobility, preservation, resiliency and overall system performance. 

To begin identifying potential solutions, the project team studied existing conditions along the I-5 corridor. Using data analysis and insights gathered through this research, the team identified system needs. The needs were then compared with existing programs, studies, and projects already underway to determine which needs were being addressed and which needs were not. Unmet needs were classified as gaps, and new proposed work is now being developed to address the gaps.

The next phase of the Master Plan focuses on prioritizing both existing planned work and new proposed work. The prioritization process combines technical data with feedback to identify the most impactful investments. It measures projects against the plan's vision and six project goals:

  • System resiliency, preservation and environmental.
  • Safety.
  • Mobility and accessibility.
  • Equity and community.
  • Economic vitality and movement of goods.
  • Innovation and future readiness.

These goals were informed by a comprehensive review of local plans, alignment with the Highway System Plan, and input gathered during the I-5 listening sessions. Projects that best align with these goals will receive the highest priority. The resulting priorities will then be refined by considering practical factors such as project readiness, funding opportunities, and alignment with existing plans. By combining prioritization results with real-world considerations, the I-5 Master Plan will deliver recommendations designed to maximize improvements across the I-5 system.

I-5 system

The I-5 system includes more than the main interstate highway. It encompasses all the infrastructure that connects to and supports the I-5 corridor, including bridges, on- and off-ramps, and even fish passages. Together, these elements serve a wide range of users, from pedestrians and cyclists to transit riders, motorists, and freight operators. The I-5 Master Plan will identify strategies to address the needs of this interconnected system while considering the diverse needs of everyone who relies on it.

History

The I-5 Master Plan evolved from work conducted by the I-5 System Partnership. The partnership was a diverse group of interested parties who recommended the development of an I-5 System Master Plan to identify specific improvements that should be made to each part of the I-5 system.

In response, the Washington State Legislature began planning for future growth. In spring 2022, the Legislature initiated the Move Ahead Washington funding package to take steps to develop the I-5 Master Plan. The plan sets priorities from border to border for a robust north/south corridor. It also reflects WSDOT's strategic plan, which includes resiliency, equity, and workforce development goals.

Listening sessions

Between August 2022 and April 2023, WSDOT held listening sessions with a wide range of interested parties. WSDOT heard from 137 jurisdictions, Tribes, agencies and organizations, including those representing underserved communities.

Listening session participants throughout the I-5 corridor shared feedback on the following themes:

  • Equity, inclusion, diversity, and accessibility.
  • Preservation investments.
  • Connected communities and accessible I-5 crossings.
  • Congestion relief.
  • Freight mobility efficiency.
  • Improved multimodal operations and transit.
  • Seismic and climate-related resiliency.

A detailed report of our listening session efforts can be found in the Listening Sessions Feedback Summary (PDF 4.6MB).

Establishing a shared vision for I-5

In late 2025, the Cascadia Program developed the I-5 Master Plan vision and goals, which were informed by input from the listening sessions, existing WSDOT plans such as the Highway System Plan, and broader WSDOT goals of furthering an integrated multimodal transportation system. The draft Master Plan goals will be finalized following additional engagement in the fall of 2026.

Documenting existing conditions

The Cascadia Program launched the I-5 Master Plan in mid-2024 by collecting county-level transportation, environmental, and demographic data along the 277-mile I-5 corridor to establish existing and anticipated future conditions. The existing conditions analysis supports the Master Plan by providing the basis for defining and identifying needs for the corridor today and into the future.

Additional resources

Related WSDOT Projects: