Project Title & Location

SR509 I-5 Freight & Congestion Relief Project in Kent, SeaTac, Des Moines & Federal Way.

Project Description
The SR 509/I-5 Freight and Congestion Relief Project will ease congestion on I-5, improve freight mobility, lower travel times, accommodate plans for a new south-oriented access to Sea-Tac International Airport, and increase safety on south King County roadways. In addition, the project includes several environmental improvements. The 2005 Transportation Partnership Account will fund continued design and right-of-way acquisition. The project may be constructed in phases depending on funding.

Contractor/Consultant
HNTB Corporation is prime design consultant.  Other consultants working on SR 509 include Carter Burgess, Jacobs and TBE

Recent Progress

Record of Decision signed by FHWA on March 20, 2003.  Access Point Decision Report approved by FHWA on April 17, 2003.  I-5 Findings and Order signed and I-5 right of way plans approved in April 2004.  SR 509 Access Hearing held in June 2004. Geometric and hydraulic design work is underway and on schedule.  For more information, please see the project web site:  www.wsdot.wa.gov/projects/I5DesMoinesWaySouth188St/

Design Construction Impacts
Design revision for the SR 509/ South Access (to Sea-Tac Airport) Interchange has been proposed and is being considered by the SR 509 Steering and Executive Committees.  The 2004 Cost Estimate Validation Process (CEVP^TM)  for the entire SR 509 project estimates construction durations of six to eight years and $883 million additional funding needed.  Funding for the remaining right of way purchases and construction depends on additional funding from the Regional Transportation Investment District (RTID).   The Nickel Funding Package funds will be used by Jan. 2007.  If RTID funding is not received, work on the project will cease and total cost to complete will increase.

Environmental Impacts / Compliance
As part of the Nickel Funding Package, the SR 509 project will contribute up to $9 million to the construction cost of the Des Moines Creek Basin Plan projects and will use the facilities to help manage SR 509 storm water runoff.  This construction started in July 2004.    For the entire SR 509 project, permit applications are being prepared.  Wetland impacts have been reduced to less than ½ acre.  The Talent federal court decision may change the amount of wetlands impacted.

Impacts to Traffic

When complete, the SR 509 project will reduce congestion on I-5, reducing travel times by up to 12 minutes between Seattle and Tacoma.  The project will give commuters a choice of routes, thereby reducing trip distances and trip times. The new route provides direct freight access between Kent, the Port of Seattle and the Duwamish industrial area.  Airport access from the south will be improved, reducing traffic impacts on local streets and I-5.

During construction, four lanes of I-5 will remain open in the peak direction during the peak hours.  

City of SeaTac is project lead.  First working day was in June 2004.

Planned vs. Actual Expenditures
(Total Project Cost)

Nickel funds included in above costs

2005 Transportation Partnership Account