42nd Ave Bridge S Replacement Project

Project Status Update – 8/2023

Between the type, size, and location report submittal and the 30% P&E submittal, it was estimated that the Plans, Specifications, and Estimate for construction advertisement would be available by December 2023. At the 30% P&E submittal milestone, TranTech’s permit subconsultant began verifying what agencies require permit applications. The majority of the permitting agencies will not field/take applications for permits until the 30% P&E threshold is met. With the transition to 60% P&E, permit agencies informed project staff that internal permit processes require additional time for review and acceptance, partially due to staff shortages and constraints. With a better understanding of the permit application and timeline, the timeline has been adjusted to have advertisement ready documents ready in December 2024. For the 42nd Ave S Bridge replacement, the project team is coordinating with: Department of Natural Resources, US Army Corps of Engineers, US Coast Guard, Federal Highway Administration, Washington State Department of Transportation, Washington Department of Ecology, Washington State Department of Fish and Wildlife, King County Parks and Recreation, King County Sewer, Seattle City Light, local businesses, and Tukwila’s Department of Community Development. The project staff will also coordinate with multiple utility providers to relocate current infrastructure.



The 42nd Ave S Bridge is an important arterial for the City of Tukwila and surrounding communities. The bridge, designed in 1927 and built in 1949, is reaching the end of its design lifespan and needs to be replaced. The current 42nd Ave S Bridge consists of a 3-span 280-foot-long bridge with a new sufficiency rating of 6.00 out of 100 due the bridge strike and is considered both Structurally Deficient and Functionally Obsolete by the Federal Highway Authority (FHWA). The 2018 average daily traffic volume (ADT) was 10,300 vehicles per day.

A consultant team has been brought onboard by the City to develop a design for a replacement bridge. A component of the design work will involve gathering feedback from community stakeholders to guide portions of the design process. There will be multiple opportunities for the public to share their thoughts on bridge design and other project features.



Sign Up Now



The project is currently in the design phase which will continue through 2024.

Timeline Description
June 2023 City Review of 60% Plans and Estimate
January 2024 90% Plans, Specifications, and Estimate Submittal
February 2024 City Review of 90% Plans, Specifications, and Estimate
September 2024 100% Plans, Specifications, and Estimate Submittal
October 2024 City and WSDOT review of 100% Plans, Specifications, and Estimate
December 2024 Plans, Specifications, and Estimate ready for construction advertisement



What is the status of the 42nd Ave S Bridge?

The 42nd Ave S Bridge has been monitored in accordance with federal requirements, and since 2015, has been the subject of concern and evaluation by Tukwila Public Works, King County, and the Washington State Department of Transportation. Currently, the 42nd Ave S. Bridge carries a sufficiency rating (SR) of 6.00 on a scale of 100 – this means that the bridge is in poor condition and in need of replacement. Specific technical examples of the bridge’s deterioration include compromised area due to truck strike, loss of shoreline protection, concrete cracking at the north pier, frozen bridge bearings, corrosion, pack rust, and impact damage on a fracture critical bridge. The primary responsibility of city government is to uphold and protect public safety, including the maintenance of infrastructure. In Tukwila, we are committed to a safe, transparent, and orderly replacement of this bridge.


Where are we in the process of replacing the 42nd Ave S Bridge?

The City just returned the 60% plans and estimate comments back to the design engineers. The design team will incorporate the new questions/comments and move toward the 90% plans and estimate milestone.

Permit/Compliance Agency Estimated Agency Review Duration Estimated Permit/Approval Acquisition
SEPA City 120 days December 2023
Shoreline Master Program City 120 days December 2023
NEPA CE WSDOT 15 days October 2024
Section 4(f) – Green River Trail WSDOT 30 days July 2023
Section 4(f) – Tukwila Community Center WSDOT 30 days July 2023
Section 106 National Historic Preservation Act DAHP (WSDOT) 45 days November 2023
Section 7 ESA (Biological Assessment) NOAA/USFWS (WSDOT) Up to one year October 2024
Section 10 RHA/Section 404 CWA US Army Corps of Engineers Up to one year November 2024
Aquatic Land Easement –

Existing Bridge (demo access)

DNR Up to one year November 2024
Aquatic Land Easement –

Temp Bridge

DNR Up to one year November 2024
Aquatic Land Easement –

New Bridge

DNR Up to one year November 2024
Aquatic Land Easement – Construction Easement DNR Up to one year November 2024
Aquatic Land Easement –

Water Line

DNR Up to one year November 2024
Aquatic Land Easement –

PSE Gas Line

DNR Up to one year November 2024
Hydraulic Project Approval WDFW 45 days February 2024
Section 9 RHA/Bridge Permit US Coast Guard N/A Complete


Do you have an emergency plan in place in case the 42nd Ave S Bridge collapses? 

The City closed the 42nd Ave S Bridge in December 2021 due to an over height bridge strike. General vehicle traffic was then detoured to S 115th St and trucks were detoured to the S 129th St Bridge.

An analysis of the one-way traffic was performed six (6) months after the bridge was open. It was recommended that the 42nd Avenue S bridge continue to operate in the southbound direction. It is safer and more efficient for vehicles to exit the neighborhood using the traffic signal at the 42nd Avenue S/Interurban Avenue S intersection compared to exiting the neighborhood at the unsignalized S 115th Street/East Marginal Way S intersection.

Emergency response in any jurisdiction takes several factors into account, including the cause of any major incident. Whether failure of any structure is caused by fire or flood or natural disaster, responders first on the scene of any emergency situation are trained professionals who help to alert and call into service the appropriate agencies, and identify expertise and equipment needed to be most effective in securing and protecting public safety. As a best practice in emergency management, any emergency response of this scale would be managed and coordinated in accordance with the direction of the Tukwila Emergency Manager, King County, and the State of Washington.

How are you going to mitigate impacts during construction of the bridge, both to traffic in the Allentown neighborhood and to amenities such as the Community Center and spray park?

City has hired a design consultant to design the 42nd Ave Bridge replacement. As part of this design, the consultant will evaluate traffic rerouting during the construction phase of the project.  If the reroute impacts the Tukwila Community Center, alternative temporary improvements can be made available during the time of construction to mitigate the impacts. More information on potential reroutes will be developed as the bridge design progresses and will be shared with the community. Furthermore, any construction impacts to the Tukwila Community Center will be rehabilitated to equal or better pre-construction conditions.

A temporary bridge is planned to be constructed just to the east of the 42nd Ave S Bridge during the demolition and construction of the new bridge. The temporary bridge will again bring two-way traffic in and out of Allentown.


Why isn’t the City of Tukwila conducting an EIS for the 42nd Ave S Bridge?

The new bridge at 42nd Ave S will replace existing infrastructure and is not expected to have significant impacts requiring preparation of an EIS. However, environmental analysis is being conducted following applicable State Environmental Policy Act (SEPA) and National Environmental Policy Act (NEPA) procedures.

The City of Tukwila is committed to working with stakeholders as part of that process, including Allentown residents, local Tribes, Washington Department of Fish and Wildlife (WDFW), United States Fish and Wildlife Service (USFWS), United States Army Corps of Engineers (USACE), City of Tukwila Department of Community Development, Washington State Department of Transportation (WSDOT), US Coast Guard, Department of Ecology (DOE), Department of Archaeology and  Historic Preservation (DAHP), Department of Natural Resources (DNR), National Oceanic and Atmospheric Administration (NOAA) National Marine Fisheries Service.

The City is currently conducting an EIS study for the Allentown Truck Reroute project. Please refer to the following link for information on that project.


What can you do about trucks speeding on the 42nd Ave S Bridge and through the Allentown neighborhood? And relatedly, can you do more to enforce weight/speed restrictions on the bridge?

The roads near and through Allentown, as well as heavily trafficked roads in many neighborhoods in Tukwila, are monitored to determine traffic patterns and usage. The City has performed a traffic study for the Allentown neighborhood and other neighborhoods in the City. The assessment includes collecting traffic data that will help us to identify issues with factors such as speed and solutions that could include safety measures like lighting, sidewalks, crosswalks, curbs, speed limits and enforcement, to help protect residents and drivers.


What other kinds of fundraising has the City undertaken to get funds for this project and a replacement bridge?

Since 2017, the City has been actively applying for grant funding for the 42nd Ave S Bridge Replacement Project. These grants are highly competitive, and the City was unsuccessful in receiving grant funds for this project until 2021.

The City has received grant funding from- $1.5 million from the Puget Sound Regional Council to complete the 100% design phase and move the project into construction by 2024, and $12 million from the Washington State Department of Transportation’s Local Bridge Program, which can be allocated for all project phases. Additionally, the Washington State Legislature passed the $17 billion Move Ahead WA transportation package, which included $17 million for the replacement of the 42nd Avenue Bridge.





For general project questions, please contact Adam Cox at 206-431-2446 or email Adam.Cox@TukwilaWA.gov.