Voters approved funding for BRT in fall 2016 as part of the Sound Transit 3 (ST3) Plan. This plan established a “representative project,” which included a high-level approach to the project, cost estimates, ridership expectations, and the number of stations and station locations.

From 2018 to early 2019, we evaluated and refined the I-405 representative project based on technical analysis and community feedback. We developed a “refined project” with roadway modifications, station-specific adjustments and additional transit-priority improvements. In March 2019, the Sound Transit Board of Directors approved this refined project and the project team began the conceptual engineering and environmental review that’s now underway.

We worked with agency and jurisdiction representatives, along with the broader community, to collect feedback about the initial project and develop initial project refinements.

Based on that feedback, we developed criteria such as BRT travel time, service reliability, access to the stations for people walking or biking, and vehicular access to evaluate the refinements.

WSDOT is working on a design to widen I-405 to provide dual ETLs from the SR 527 through the SR 522 interchange.  Direct access ramps to the ETLs will be built at SR 527 and SR 522, which will also provide space for inline I-405 BRT stations. Moving the stations to the direct access ramps allows the BRT buses to run faster along I-405 in the ETL while dropping off and picking up passengers quickly and easily.

WSDOT will also begin construction on a southern expansion of the ETLs from Renton to Bellevue in 2020.

These projects align with the schedule of Sound Transit’s Stride BRT projects and will provide additional roadway capacity for Stride BRT buses.

Transit priority improvements help buses move through traffic more efficiently and can include bus lanes and transit priority signals. We will continue to coordinate with our partners to improve travel times along the route during the conceptual engineering and environmental review phase.

The proposed refined project has updated ridership projections, forecasted for the year 2042:

What is SEPA and the SEPA checklist?

SEPA (State Environmental Policy Act) was created to give agencies the tools to allow them to consider and mitigate for environmental impacts of proposals. Analysis of environmental impacts through a SEPA process is intended to ensure that environmental values are considered during decision-making by state and local agencies. A checklist is one method used through the SEPA process to identify, analyze and disclose environmental impacts associated with government and agency decisions.

If you’re interested in more details on how the SEPA process works, check out the Washington Department of Ecology’s website and Sound Transit’s SEPA Rules.

What happens after the SEPA checklist is completed?

After evaluating the project and identifying any necessary mitigation measures, Sound Transit will determine whether a proposal will still have any likely significant adverse environmental impacts. The checklist will then be provided for public review, and Sound Transit will also publish a decision about the outcome of environmental analysis: a Threshold Determination. The Threshold Determination may be either a Determination of Non-significance (DNS), which may include mitigation conditions, or a Determination of Significance, which means the proposal was determined to have a likely significant adverse environmental impact.

The Sound Transit Board will consider the environmental review, along with technical and economic information, when deciding if to advance the project components into a final design phase.

Will I be able to provide feedback on the SEPA checklist?

Yes. If the Threshold Determination is a Determination of Non-significance (DNS), you will be able to review and provide comments during a 14-day comment period. The checklist and Threshold Determination will likely be published in 2020.

We will conduct detailed transportation assessments for the road networks near the proposed improvements with a focus on multi-modal access to transit, bus-base circulation and overall BRT mobility. The transportation analysis includes the following:

• Lynnwood City Center – BRT routing, access, and speed and reliability improvements to the transit center
• Bus Base North – Bus base traffic impacts, access considerations and BRT travel time reduction strategies (the Bus Base North project is being conducted separately from the I-405 BRT Project)
• Kingsgate Park and Ride – Expanded park and ride traffic impacts, vehicular circulation and potential access strategies
• South Renton Transit Center – BRT circulation and transit center access and park and ride access
• Tukwila International Boulevard Station – SR 518 freeway configuration and operations, BRT station operations and access considerations
• Burien Transit Center – BRT routing, transit center access, and speed and reliability improvements on SW 148th Street and at the SR 509 interchange

In addition, Stride BRT ridership levels will be estimated for each station location along the route.

We will analyze the effects of the I-405 BRT Project on existing residential and other noise-sensitive land uses at approximately 15 locations along the corridor. Noise measurements will be conducted at these locations to define the existing noise levels. We will study potential noise impacts at the new BRT stations, transit centers and roadway improvement areas by comparing the future noise of the project components to the existing noise levels. We will also evaluate the potential for noise and vibration impacts from construction of the project and identify ways to mitigate these impacts.

We will evaluate the project components’ potential changes to visual resources and character, and evaluate how those changes affect visual quality as seen from nearby views. The visual impact assessment will consider a variety of viewers, including motorists, recreationists, employees and residents and if there are designated scenic resources or specific visual goals in local plans.

The environmental analysis will also consider project construction and operational impacts related to the following:

• Earth
• Air
• Water (surface water, groundwater, stormwater)
• Plants and animals
• Energy and natural resources
• Environmental health (hazardous materials/contamination, noise)
• Land and shoreline use
• Housing
• Aesthetics, light and glare
• Recreation
• Historic and cultural preservation
• Transportation
• Pubic services
• Utilities

This BRT station will be at the existing Lynnwood Transit Center adjacent to the future Link light rail station, which is currently under construction and will begin service in 2024. Riders will be able to connect to local and express buses, Swift and Link light rail.

BRT buses will run between the Lynnwood Transit Center and I-5 via 44th Avenue W and 196th Street SW. Routing improvements between the Lynnwood Transit Center and I-5 include widening at the northbound I-5 on-ramp on Poplar Way. Sound Transit will also work with the City of Lynnwood to coordinate how best to use the signals along 196th Street SW to improve speed and reliability of buses going between I-5 and the Lynnwood Transit Center. Buses will then run on I-5 to access I-405.

The expansion of the ETLs north through Bothell provides an opportunity to build inline BRT stations at Canyon Park, the SR 522/I-405 Transit Hub (located at the I-405 and SR 522 interchange) and Brickyard in partnership with WSDOT.

Buses will briefly exit the ETL on the left and stop at a station between the northbound and southbound segments of I-405. These inline stations help improve bus speed and reliability.

The Canyon Park BRT station will be located just west of the Canyon Park Park and Ride on new direct access ramps to the ETLs.

The inline BRT station at the SR 522/I-405 Transit Hub will also be on a direct access ramp.  I-405 BRT will connect with SR 522/NE 145th BRT at this location. Learn more about SR 522/NE 145th BRT on the project website.  More information about the BRT connection will be available as the BRT and ETL projects develop.

The Brickyard station will be a transit-only inline BRT station facility.

This BRT station will be at the existing Totem Lake freeway station. Buses will briefly exit the ETL on the left and stop at the BRT station between the northbound and southbound segments of I-405.

The I-405 BRT Project will also build a parking garage that adds 400 parking stalls at the Kingsgate Park and Ride. WSDOT is concurrently studying the feasibility of transit-oriented development (TOD) at this site.

In partnership with WSDOT, we are building a new three-tiered interchange with an inline BRT station and access to the ETLs.

This BRT station will be at the existing Bellevue Transit Center. Buses will exit from the ETLs to access the transit center. Riders will be able to connect to local and express buses, RapidRide and Link light rail at the future Bellevue Downtown Station. The north and south BRT lines will connect at this station.

Riders continuing past Bellevue to Burien will need to transfer to the other I-405 BRT line.

This BRT station is a new inline station that will be built as part of the ETLs from Bellevue to Renton. Buses will briefly exit the ETL on the left and stop at a station between the northbound and southbound segments of I-405.

This station also includes a new 200-stall park and ride facility. 

We are building a new transit center in South Renton at Rainier Avenue S and S Grady Way. The site is next to an existing WSDOT park and ride.

The transit center will include a new 700-stall parking garage with pick-up and drop-off areas. We have left part of this site for future transit-oriented development, such as housing or hotels.

This is a new freeway BRT station on SR 518.

Riders will be able to connect to existing light rail service via a new pedestrian bridge. This will provide an easy transfer for BRT riders looking to travel to the airport or Seattle.

This BRT station will be located at the existing Burien Transit Center.

1. Orient your device to view in "landscape" mode
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1. Click and drag using your mouse to view the BRT shelter and surrounding environment
2. Click the arrows in the bottom left corner to experience different viewpoints around the BRT shelter

Sound Transit is committed to reaching and hearing from those historically underserved and most highly impacted. The project team is engaging with local community organizations, social service providers, property owners and tenants along the corridor to ensure their thoughts are heard and needs are met as the project progresses.

Are you a member of a community organization or service provider, or a property owner or tenant along the project corridor?

Let us know if you’d like a briefing on the project or to meet with a community outreach specialist at brt@soundtransit.org or (206) 398-5470.

We've also been working with the city of Kirkland, city of Renton and WSDOT on station area updates and TOD opportunities.

Learn more about the project's stakeholders in our Community Engagement Guide.

Our project staff are coordinating with King County Metro, Community Transit and WSDOT staff on their projects in the area. If you have questions or comments about their services, please contact them through the links provided below:

• King County Metro
• Community Transit
• WSDOT

Keep in touch!

• Visit the project webpage to learn more about the history of the project and details about the design
• Sign up for project email updates to stay up to date throughout project development
• Read our updated Frequently Asked Questions for more information and our answers to commonly asked questions about the project