Project Facts
- WSDOT is developing plans to improve traffic flow and safety.
- The project will modify the I-5/SR 18 interchange to eliminate weaving vehicle movements.
- We will build the project in phases, starting in 2010.
May 2008
- We are evaluating improvements for potential environmental sites in the project area.
- We are working to obtain necessary property for project construction.
- We published an informational packet (folio pdf 1.9 mb) about why and how we are building the project in phases.
We are designing major changes to the area where Interstate 5, SR 161 and SR 18 connect in Federal Way.
The reconstruction includes replacing two cloverleaf loop ramps with flyover ramps for westbound SR 18 to southbound I-5 traffic and eastbound SR 18 to northbound I-5 traffic. We also will provide direct access to SR 161 from southbound I-5 and westbound SR 18 by building new exit ramps at S. 356th Street and S. 359th Street.
Due to limited funding, WSDOT will construct these improvements in phases.
Why is WSDOT
designing improvements to the I-5 - SR 161 - SR 18 Triangle?
The I-5, SR 161 and SR 18 triangle has severe traffic congestion and safety problems. Traffic volumes in this area are expected to greatly increase in the next 20 years, due to projected growth in south King and north Pierce counties. There are also major safety deficiencies at the interchange of I-5 and SR 18. The existing loop ramps are substandard and two of the loop ramps are high-accident locations. These improvements will improve traffic flow and safety at this increasingly congested interchange.
The End Result
The project will modify the I-5/SR 18 interchange to eliminate weaving vehicle movements. We have selected a preferred alternative that will improve existing and future traffic circulation, reduce the number and severity of accidents in the vicinity of I-5, SR 161 and SR 18, and avoid or reduce the effects on the environment.
Project Benefits
- Safety: Improvements to the I-5, SR 161 and SR 18 interchange will eliminate weaving vehicle movements by removing two cloverleaf loop ramps.
- Congestion relief: The selected preferred alternative will improve traffic flow while reducing the number and severity of accidents.
What is the project timeline?
March 2005: Hold an open house and comment period (pdf 184 kb) to share our new design alternative with the public.
April 2005: Begin environmental studies.
Spring 2005: Select a preferred alternative.
Fall 2005: Begin early project design.
January/February 2007: Complete the environmental documentation.
Summer 2007: Begin final design phase of the project
Fall 2009: Accept bids for private contractors.
2010: Begin construction of the project. We expect construction of the first phase to take about two years. We are building the project in phases because we do not have enough funding to build the entire project at this time.
Public Involvement
We recently published an informational packet outlining the project phases and potential funding sources. You can download a printable version (folio pdf 1.9 mb) or contact the project office for a copy.
The project team hosted an open house on Jan. 30, 2007 to present environmental findings and design plans for the intersection. For more information contact the project office.
We held an open house and comment period (pdf 184 kb) in March 2005 to share our new design alternative with the public.
We also will send periodic e-mail updates. If you would like to receive these updates please contact the project engineer, Bruce Nebbitt at nebbieb@wsdot.wa.gov.
Environmental Protection
WSDOT in partnership the City of Federal Way, King County, the City of Milton, and the Federal Highway Administration completed a preliminary environmental review. The preliminary environmental reports did not identify any significant harm to the environment as a result of this project. WSDOT proposed and the Federal Highway Administration agreed to switch the environmental process for this project from an environmental assessment (EA) to a documented categorical exclusion (DCE). This means that the selected design for this project does not affect planned growth or land use of the area. Also the project does not significantly harm the air, noise, or water quality of those living in the area.
We have submitted a Biological Assessment that describes how we will protect the environment during and after construction. We will construct several detention and drainage ponds to treat highway run-off created from the extra pavement constructed for the project. These ponds will improve water quality and protect sensitive waterways in the project area.
Please visit the WSDOT Environmental
Services Web site for more information.
Increasing safety is one of our priorities
This project will modify the interchange to eliminate the weaving movements of vehicles by improving the connections of I-5, SR 161 and SR 18.
Will this project impact tribal resources?
At WSDOT we seek to address the concerns of the tribal nations using the process outlined in Section 106 of The National Historic Preservation Act and the WSDOT Tribal Consultation Policy adopted in 2003 by the Transportation Commission as part of the WSDOT Centennial Accord Plan.
Section 106 consultation was initiated with the Muckleshoot, Puyallup, Yakama, and Duwamish Tribes in March of 2004. Once the preferred alternative was selected, Section 106 consultation was reinitiated in April of 2005. A Cultural Resource Survey is currently being prepared and when it is, it will be sent to the Tribes for their review and comment.
Financial Information
This project is funded through the following fund sources.
- 2005 Gas Tax (Partnership Funding) - $100,000,000
- 2003 Gas Tax (Nickel Funding) - $3,008,000
- Existing Funds - $687,000
- Other Agency Funds - $8.2 million (federal funds)
- Total Funding From All Sources - $112 million
- 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. Other sources of money for this project have not been identified.
How can I get more information?
Contact:
Project Engineer: Bruce Nebbitt
Phone: (206) 716-1170
E-mail: nebbieb@wsdot.wa.gov
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