Find Posts By Topic

We’ll build a new bike lane on West Marginal Way SW after the West Seattle Bridge reopens in 2022

West Marginal Way SW and the Duwamish River viewed from above. Photo Credit: Google Earth.


  • West Marginal Way SW is part of a critical detour network while the West Seattle High-Rise Bridge remains closed to traffic. We will install a new bike lane on West Marginal Way SW in 2022, after the high bridge reopens. 
  • The new bike lane will complete the all-ages-and-abilities network between South Park and the West Seattle Bridge Trail and beyond, including Alki, the Junction, downtown Seattle, and SODO. It will also enhance safety for everyone along West Marginal Way SW. 
  • This announcement also comes after comprehensive traffic data analysis, which predicts that adding the new bike lane will have minimal impacts on the number of vehicles that  use the street and how long it takes to drive in the area. 
  • Starting this weekend, people traveling the detour route at West Marginal Way SW and Highland Park Way will see us improving the intersection to make it more accessible, efficient, and safe. This includes a new northbound lane and a right turn arrow for westbound right turns. 
  • Have questions about the work we’re doing to reopen the bridge to traffic and manage traffic while the bridge is closed? We hope you’ll attend our virtual public meeting on July 21 at 5:30 PM. Learn more and join here 

West Marginal Way SW is part of a critical detour path while the West Seattle High-Rise Bridge remains closed to traffic. We will install a new bike lane on West Marginal Way SW in 2022, after the high bridge reopens. 

Planned layout of West Marginal Way SW, looking north. 

The redesigned street will give additional space to people walking, biking, and rolling on this important freight corridor. 

Moving freight and goods remains the priority for this major truck street which serves port facilities, cargo yards, and major businesses. We carefully considered this distinction and the importance of maintaining freight reliability during the high bridge closure as we developed the new street design and  implementation timeline. 

The planned street redesign will further separate vulnerable people from faster-traveling traffic and trucks. The new bike lane complements the new sidewalk north of the Duwamish Longhouse and Cultural Center and the  crossing signal at the Duwamish Longhouse scheduled to be installed this year. 

This announcement comes after months of engagement with key stakeholders, including our bicycle and freight advisory boards, transportation safety advocates, local businesses, community groups and members, the Port of Seattle and maritime industrial community, and the West Seattle Bridge Community Task Force. The feedback we received from these various groups was mixed. Some asked for the bike lane to be installed this year while others requested installation after the high bridge reopens in 2022. 

The new bike lane will complete the all-ages-and-abilities network between South Park and the West Seattle Bridge Trail and beyond, including Alki, the Junction, downtown Seattle, and SODO. It will also enhance safety for everyone along West Marginal Way SW. 

Better, safer bike lanes make riding a bike a more viable transportation option around the city. As we prepare for our new normal, Seattle has the opportunity to build lasting, positive change toward a more livable, safer city for all.


Especially now, people who live, work, and visit Seattle need safe, healthy, and affordable options to get around. Protected bike lanes are one piece of the puzzle to help people travel safely while Seattle moves on from the pandemic and fights the climate crisis. 

Bike lane on SW Avalon Way. Photo Credit: SDOT. 

This project will also enhance safety for everyone driving by encouraging slower driving speeds, eliminating high-speed passing, improving visibility for people entering from side streets, and improving the predictability of all people using West Marginal Way SW. 

This announcement also comes after comprehensive traffic data analysis, which  predicts that adding the new bike lane will have minimal impacts on the number of vehicles that  use the street and how long it takes to drive in the area.  

Our studies looked at potential delays for someone driving a truck after the bike lane is installed and found the expected to delay to be minor during peak traffic after the high bridge reopens next year. 

Since the high bridge closure in March 2020, West Marginal Way SW has seen about 15,000 more vehicles per day, as expected for a signed detour route. Waiting until traffic returns to the high bridge next year and traffic volumes on West Marginal Way SW return to baseline numbers, allows us to prioritize the high bridge detour network over the next year and commit to a long-term project that completes a section of the citywide bike network.  

Today, West Marginal Way SW has 3 travel lanes (2 northbound and 1 southbound) and a center turn lane that extend through the full length of the corridor. All three continuous lanes, as well as a center turn lane, will be maintained for through-traffic.  

The two-way protected bike lane and parking lane will be built on the western side of the street in the southbound lane that begins south of the Chelan 5-way intersection and bridge structures that limit the capacity to West Marginal Way SW.  Redesigning the extra lane that does not go all the way through the corridor leads to a smoother and more predictable trip for people driving without unnecessary merging, eliminates high-speed passing, or the need to navigate around slower moving bicycles.  

The new bike lane is one part of a larger plan to improve the West Marginal Way SW corridor for everyone.  

Starting this weekend, people traveling through the intersection of West Marginal Way SW and Highland Park Way will see us working on improvements to make it more accessible, efficient, and safe. This includes a new northbound lane. 

We have a few plans for the intersection. We will: 

  • Remove existing raised traffic islands to create a new northbound lane, and shift the southbound left turn lanes farther west to reduce wait times.  
  • Update the traffic signal equipment for people of all abilities, which will allow us to make signal adjustments in real-time remotely from our traffic operations center based on what cameras show 
  • Install new accessible curb ramps 
  • Relocate the bus stop 
  • Improve turning movements for vehicles traveling through the intersection to shorten wait times 

Our construction will minimize impacts to the traveling public as much as possible.  

For more information: