December 2011
- With full project funding currently unavailable, WSDOT plans to complete this project in two or three phases.
- An initial phase is currently being considered as part of a SR 509 tolling study using a collaborative decision making process among the project partners.
- The study is to be completed early 2012. Other elements of the project will remain on hold until funding is available.
- The I-5/SR 509 Project is one of five projects that the state is studying for as to develop methodology for evaluating Public Private Partnership projects.
- The state Legislature is expected to consider short-term funding for the project during the 2012 session.
Why is WSDOT
extending SR 509?
Extending SR 509 will ease congestion on I-5, improve service between industrial districts by allowing general-purpose traffic and up to 9,000 trucks per day to bypass I-5, SR 99 and local streets, and provide for southern access to Sea-Tac International Airport.
What does the Initial Phase include?
The Initial Phase includes constructing a four-lane road between South 210th Street and South 188th Street in SeaTac and Burien, providing a new I-5/SR 509 interchange, and adding collector/distributor lanes to I-5 from South 210th Street to SR 516.
The I-5/SR 516 interchange would be rebuilt, including a new connection to South S. 231st Way. New south-bound Collector Distributor lanes would be added from the new I-5/SR509 interchange to S. 320th street interchange. A new direct access to Sea–Tac Airport from SR 509 would be provided at South 200th Street along with a new connection to the SeaTac business district at 24th/28th Avenue South.
The End Result
When finished, SR 509, the South Airport Access roadway, new I-5 lanes and improvements will become a key component of the Seattle and south King County transportation network. When considered in conjunction with the planned Alaskan Way Viaduct improvements, the project provides a critical north-south corridor alternative to I-5 through Seattle and South King County.
View a map of the project area.
Project Benefits
- Congestion. Reduces congestion on I-5 in South King County by providing an alternate north-south route to I-5 while increasing I-5 capacity.
- Safety. Increasing capacity and improving traffic flow reduces the risk and frequency of accidents.
- Freight. Provides a direct route for freight and general traffic movements to and from the Puget Sound marine ports and the industrial areas of Seattle and South King County.
- Airport access. Provides for a direct connection between I-5 and Sea-Tac Airport from the south.
- Public value. By reducing travel times between Seattle and Tacoma by up to 12 minutes, the traveling public saves more than $100 million per year in travel time.
What is the project timeline?
2005 - 2009
- Obtain state and federal permits required for construction
- Completed initial-phase design
- Completed property acquisition
- Continue utility-coordination efforts and relocation planning.
For more detailed project schedule information, please visit the schedule page, or contact the project office with schedule-related questions.
Financial Information
The 2008 cost estimate for the SR 509 initial phase is $1.2 billion to $1.3 billion. The latter estimate includes spent funds, the $35 million in new funding from the 2003 Nickel funding package and the $30 million in new funding received as part of the 2005 TPA funding package. Cost estimate range depends on when funding is available and inflation.
This project received funding through the following sources:
- 2005 Gas Tax -$30 million
- 2003 Gas Tax - $35 million
- Other funds - $21 million
(from pre-existing state, federal and other partnerships)
- Funding available from all sources - $86 million
- Unfunded - $1.2 billion
Voters in King, Pierce and Snohomish counties did not approve Proposition 1, which included some funding for this project as part of the 2007 Regional Transportation Investment District Blueprint for Progress.
How can I get more information?
Contact:
Susan Everett
Project Development Engineer
999 Third Ave., Suite 2424
Seattle, WA 98104
206-805-5422
Mike Murphy
WSDOT Communications
MurphyM@wsdot.wa.gov
206-440-4699
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