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As we hit the 6-month mark of the West Seattle Bridge closure, the Community Task Force met for the 9th time, and we shared an update on our plans for West Marginal Way.

Downtown Seattle viewed from the West Seattle High-Rise Bridge. Photo Credit: SDOT Flickr.


At our ninth Community Task Force Meeting, we used a new platform – Zoom – which enabled us to enhance accessibility to the meeting content. We also live-streamed the event on YouTube (which we’ll do for all meetings moving forward, too)! If you weren’t able to tune in, see the meeting recordings below. 

At the meeting, we shared these updates and heard feedback from the Community Task Force: 

West Seattle High-Rise Bridge Stabilization Work is continuing, and stay tuned for video in an upcoming blog. 

We’ve been providing weekly updates on our blog, and through the West Seattle Bridge emails, which you can sign up for. In the meeting, we showed the large steel brackets that we will use for the external post-tensioning. These strands will be attached to the inside of the concrete box girders. We also showed the equipment used to deliver the post-tensioning brackets to the bridge. You can learn more about the post-tensioning system in our blog post from June

Crews delivering the post-tensioning brackets to the High-Rise Bridge. Photo Credit: SDOT
Crews delivering the post-tensioning brackets to the High-Rise Bridge. Photo Credit: SDOT 

We will be sharing videos of this delivery and installation soon! 

The Low Bridge Subcommittee is almost fully formed, and will meet for the first time next week. 

West Seattle Low Bridge support dome.
West Seattle Low Bridge support dome. Photo Credit: SDOT Flickr. 

As we mentioned in our last meeting, we are working to form a subcommittee to inform how we allocate limited space on the Low Bridge to various types of traffic (in other words, our “allocation policies”).

The subcommittee now consists of five confirmed members from the Community Task Force representing a variety of sectors, and one person representing another stakeholder organization, TransWest. Agency staff represent SDOT, the Office of Economic Development, the Port of Seattle, and King County Metro Transit and Vanpools.

The subcommittee will meet for the first time next week to start getting up to speed on the coming transition to automated enforcement on the Low Bridge. 

We still want to represent important voices, including critical medical travel needs, and Duwamish Valley residents who travel to West Seattle.  

The cost-benefit analysis is one important component of our collective decision to repair or replace the bridge.  

We’ve discussed the detailed process of the CBA in our blog, and most recently the role of attribute “weighting.” (Some criteria are more important to the community than others, so those criteria will hold more “weight” in the CBA.) As a reminder, mobility impacts, seismic/safety and constructability were given the highest weights after we pulled together feedback. 

Mobility: How will this repair/replace concept contribute to the movement of people and goods and overall access?  How will it impact vulnerable communities (seniors, people with disabilities and others) from accessing social service needs such as meals, healthcare services, case management, and other vital services?  

Seismic resilience and safety: What seismic standards will the repair/replace concept meet? How will seismic upgrades be incorporated into the design? 

Constructability: Will the contractor be able to build this repair/replace concept given site constraints and schedule?

This week, we reviewed and discussed: 

How we will be tangibly measuring these attributes.

For example, to measure “mobility impacts,” we are evaluating the effects of construction on regional mobility, including travel times, routes, and mode shifts – as well as the replaced/repaired structure’s increased mobility. 

Schedule (time) as a primary component in most attributes and measurables. 

Schedule/time is a primary driver behind many of our risks. Timing is one of our most important considerations.

Our three main categories of risks.  

  • Schedule risks include delays securing funding, permits and agency approvals, impacts of other projects on construction schedules, or discovery of new information (e.g. soil conditions). 
  • Stakeholder/public risks include lack of stakeholder support for repair/replace decision or for future design alternatives. 
  • Technical risks include accurately predicting how the High Bridge will respond to current stabilization measures, and working within the requirements of other agencies such as the US Coast Guard. 

We also shared an important update about our planned work along West Marginal Way.

We acknowledged that we are on the land of the Coast Salish People here in Seattle, and that our work should prioritize those whose original land we are on. As such, safe access to and from culturally significant sites along the Duwamish River has been of paramount importance to us. That is why the first thing we committed to doing on West Marginal Way once funding was secured was an important set of improvements to, from, and around the Duwamish Longhouse and Cultural Center (the Longhouse). 

The first six projects prioritize needs of many stakeholder groups: the Duwamish Longhouse and Cultural Center; people walking, rolling, and biking; people waiting in traffic; and local businesses. 

Why is West Marginal Way a priority? 

West Marginal Way is a critical street for many people, and we’ve recently seen significant increases in number and speed of vehicles traveling along the busy corridor. 

We’re tracking traffic volumes throughout the West Seattle Bridge detour routes, and two intersections – Highland Park Way SW and the Duwamish Trail – have more than doubled (and almost tripled) in traffic volume since February 2020

See below for our priority projects along West Marginal Way. Click each project in the “Project” column to view more images and information below. 

Duwamish Longhouse and Cultural Center Crossing Signal 2021-2022 
Install a crossing signal to help people walk and roll across the intersection of West Marginal Way and Herrings House Park Driveway. 

Highland Park Way S and West Marginal Way intersection By the end of 2020 
Reduce wait times and increase travel volume by moving the bus stop, creating a new right-turn only lane, and left turns will no longer be allowed from westbound Highland Park Way SW onto West Marginal Way.
Speed radar signs along West Marginal Way By the end of 2020 
Reduce speeding by installing six speed radar signs. 

West Side Sidewalk Connection Early to mid-2021 
Make it safer to walk to and from the Longhouse by installing a sidewalk on the west side of West Marginal Way.
Duwamish Trail Connection Late summer 2021, in tandem with Longhouse signal 
Explore options for the southbound, west-side travel lane along West Marginal Way, including a Duwamish Trail Connection. 

Freight Mobility Improvements Late summer 2021, after additional stakeholder engagement 
Improve freight access and safe access to and from businesses along West Marginal Way

Project 1: Install a crosswalk and traffic signal at the Duwamish Longhouse and Cultural Center (The Longhouse) 

The Duwamish Longhouse and Cultural Center shown from the outside, viewed from West Marginal Way. Four cars are parked in front. Photo Credit: SDOT Flickr.
The Duwamish Longhouse and Cultural Center. Photo Credit: SDOT Flickr. 

It is critically important to prioritize safer access to and from the Longhouse, and we’ve committed significant resources to this project. We’ll build a temporary crossing at Herrings House Park Driveway and West Marginal Way in summer 2021. A permanent crossing will come in 2022 and beyond.  

A rendering of the temporary signal at Herrings House Park driveway and West Marginal Way. Traffic lights will be on all sides of the intersection. A crosswalk is also shown. Photo Credit: SDOT.
A rendering of the temporary signal at Herrings House Park driveway and West Marginal Way. Photo Credit: SDOT. 

Project 2: Streamline the Highland Park Way SW and West Marginal Way intersection 

A map of planned improvements shows a new right turn only lane, existing bus stop, and left-turn restricted lanes in the westbound lanes of Highland Park Way SW on the east side of West Marginal Way. On the west side, a relocated bus stop is shown.
Map of planned improvements along Highland Park Way SW 

The improvements to enable 20% more westbound traffic to pass through this intersection. By restricting left turns in the westbound lanes of Highland Park Way SW, we decrease the time that people continuing straight must wait. Moving the existing bus stop from the east side of the intersection to the west leaves room for a new right-turn only lane, which further smooths traffic flow so people can get to their destination predictably without resorting to speeding through neighborhoods. 

Project 3: Install six speed radar signs along West Marginal Way 

People speed consistently along West Marginal Way, where we recently reduced the speed limit from 40 MPH to 30 MPH. The speed radar signs will help reduce speeding, which is unsafe for all travelers, including people pulling in and out of driveways. The speed radar signs will be placed along West Marginal Way from SW Marginal Pl to SW Front St. 

An overhead map is shown. Overlay shows six images of speed radar signs. Each sign has a yellow border and line that links it to a specific place along West Marginal Way.

Speed radar signs (also known as radar feedback signs) will be installed in these six locations along West Marginal Way. This is a rendering of how they will appear to drivers.

Project 4: Install a sidewalk on the west side of West Marginal Way to make it safer to walk to and from the Longhouse 

Where there is currently a planting strip, we’ll install an asphalt sidewalk on the west side of West Marginal Way. This is critically important to improve access to the Longhouse prior to project 1 – installing the crossing signal. 

Project 5: Explore options for the southbound, west-side travel lane along West Marginal Way, including a Duwamish Trail biking connection 

A map with an orange line from an existing half-signal at the north, just south of the West Seattle Bridge trail, so an existing half signal at the south at the trail crossing for West Marginal Way.

This map shows the  Duwamish Trail Connection, which would go from the Longhouse to the existing Duwamish Trail crossing signal (south of SW Idaho St). 

Near West Marginal Way, there are two marked biking routes: the West Seattle Bridge Trail and the Duwamish Trail. However, there’s a gap along West Marginal Way where there are no bike lanes – yet! Our project will help fill a gap in this bicycle network: we’ll install an approximately 0.4 mile Duwamish Trail Connection from SW Marginal Pl to the to the existing Duwamish Trail signal (south of SW Idaho St). 

Here’s what West Marginal Way would look like at the street level with the Duwamish Trail Connection: 

The graphic shown from street level shows from left to right: 11 foot sidewalk, 10 foot-wide two way bike lane (5 feet per direction), 3-foot wide barrier, 11-foot wide drive live, 10-foot wide center turn lane, 10-foot wide drive lane, 12-foot wide drive lane, and 8-foot wide planting strip.

Over the coming months, we will be working with people who ride bikes, drive, and otherwise use West Marginal Way on how to  fill the remaining gap. We’ll consider using the stretch between the Longhouse and the Duwamish Trail signal as a parking lane for the Longhouse, extending the proposed Duwamish Trail Connection above, or making it a southbound general purpose lane. If you would like to be a part of the conversation, please send us an email at  

Project 6: Make improvements to enhance freight mobility  

A semi-truck with a white cab and red freight area is shown driving up a ramp.
Truck using West Seattle Bridge in 2015. Photo Credit: SDOT Flickr. 

The West Seattle High-Rise Bridge closure and associated increased traffic along freight routes has also greatly impacted Seattle’s freight and maritime community, which supports tens of thousands of jobs along the Duwamish River and across Harbor Island, as well as the critical supply chain to Alaska, Hawaii, and worldwide.  

We’re developing a proposal to improve freight access on West Marginal Way – an important freight connection. We are currently working with West Marginal Way businesses and our freight partners on the best way to improve freight access in and out of West Marginal Way businesses. 

As a reminder, here’s a timeline for these interim and long-term improvements to help people walk, roll, bike, and drive safely along West Marginal Way: 

In phase 1, the Highland Park Way/West Marginal Way intersection and radar feedback sign projects are shown. Then in May to June 2021, the West Side Sidewalk is shown. Finally, in August 2021 the Duwamish trail connection, freight improvements, and interim longhouse signal are shown.

In 2020, we’ll install radar feedback signs along West Marginal Way and improve the Highland Park Way S and West Marginal Way intersection. Next spring, we’ll install a sidewalk near the Longhouse. This will be followed by the Duwamish Trail Connection, the interim crossing signal at the Longhouse, and freight improvements. 

These projects help all of us. If people aren’t stuck in traffic, they – hopefully – won’t feel the need to speed. If people have safe crossings and bike lanes, they’ll be more visible to and protected from drivers. If people see how fast they’re going (through feedback from the radar feedback signs!) then they’ll – typically – slow down a little

To learn more: