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Project Profile: SR 520 Bridge Replacement and HOV Program

SR 520 Bridge Replacement and HOV Program

photo credit: Washington State DOT


Seattle, Washington Metropolitan Area

Project Sponsor / Borrower

Washington State Department of Transportation (WSDOT)

Program Areas

Alternative Project DeliveryProject FinanceTolling and PricingTIFIA


Toll Bridge / Highway / Managed Lanes


State Route (SR) 520 is one of two major east-west roadways crossing Lake Washington, located within King County and the Seattle metropolitan area in the State of Washington. It connects major population and employment centers between Seattle and the region's eastern suburbs, including Bellevue and Redmond. The roadway extends from its western terminus at I-5 eastward across Lake Washington, intersecting with I-405, and continuing east to Redmond where it terminates at SR 202. Construction stretches from Seattle's University District to 108th Avenue NE in Bellevue, with restriping eventually continuing out to Redmond.

The SR 520 Bridge Replacement and HOV Program includes:

  • Pontoon Construction Project - Construction of 33 bridge pontoons and a 55-acre site on Grays Harbor in Aberdeen. Pontoon construction includes 21 longitudinal pontoons 360 feet in length, weighing approximately 11,000 tons, as well as 10 supplementary stability pontoons, and two cross pontoons.
  • Floating Bridge and Landings Project - Construction of a new six-lane floating bridge across Lake Washington to replace the aging four-lane bridge, including construction of 44 supplemental stability pontoons and removal of the existing floating bridge.
  • Eastside Transit and HOV Project - Widening of SR 520 between Evergreen Point Road at the eastern shore of the lake and 108th Avenue Northeast to six lanes, constructing three community-connecting lids and making other corridor-wide improvements to complete a transit/HOV lane in each direction. WSDOT ultimately plans to move SR 520's outside HOV lanes east of I-405 to the inside to align with the new ones.
  • SR-520: I-5 to Lake Washington (West Approach Bridge North) - Construction of a permanent, seismically sound west approach bridge structure to connect westbound traffic from the floating bridge to the Montlake Boulevard Interchange near the University of Washington in Seattle, as well as extending SR 520's new bicycle and pedestrian path from the Eastside to the Montlake neighborhood of Seattle.
  • SR 520: I-5 to Lake Washington (Rest of the West) - In addition to the West Approach Bridge North, several other project elements will be constructed between the west end of the floating bridge and the SR 520 interchange with I-5.
    • Montlake Phase - West Approach Bridge South, Montlake lid and interchange with Montlake Boulevard, and land bridge over SR 520 east of the interchange.
    • Portage Bay Phase - Six-lane Portage Bay Bridge including extension of the bicycle and pedestrian path west of Montlake Boulevard connecting to the interchange with I-5, Roanoke neighborhood lid, and I-5 connections.
    • Montlake Cut Crossing Phase - Second bascule bridge over the Montlake Cut connecting SR 520 to the University of Washington.

Total program cost - $4.56 billion

  • Pontoon Construction Project, Floating Bridge and Landings Project, Eastside Transit and HOV Project, West Approach Bridge North Project - $2.92 billion
  • Rest of the West - $1.64 billion
Funding Sources

Toll-Supported Funding

  • Toll-Backed Bonds - $660 million
  • TIFIA Direct Loan - $300 million
  • State and Local Sales Tax Deferral - $160 million
  • Toll Revenues (during construction) - $70 million

Other State and Federal Funding

  • State Funding (2003 Nickel Account and 2005 Transportation Partnership Account) - $590 million
  • State Funding (Connecting Washington Account) - $1,642 million
  • Motor Vehicle Account - $2 million
  • Direct GARVEE Bonds - $925 million
  • Other Federal Funding - $198 million
Project Delivery / Contract Method


  • Pontoon Construction Project
  • Floating Bridge and Landings Project
  • Eastside Transit and HOV Project


  • West Approach Bridge North Project
Project Partner


  • Pontoon Construction Project - Kiewit-General Joint Venture (Kiewit, General Construction Company)
  • Floating Bridge and Landings Project: Kiewit/General/Manson, A Joint Venture (Kiewit, General Construction Company, Manson Construction)
  • Eastside Transit and HOV Project: Eastside Corridor Constructors (Granite Construction Company, PCL Construction Services, HW Lochner, David Evans & Associates, Perteet)

West Approach Bridge North Contractor

  • Flatiron West, Inc.
Project Advisors / Consultants

To the State of Washington

  • CDM Smith - Traffic and Revenue Consultant
  • WSP | Parsons Brinckerhoff - Financial Planning Consultant
  • HDR - General Engineering Consultant
  • Citi Group - Counselor
  • J.P. Morgan - Counselor
  • Montague DeRose and Associates - Financial Advisor
  • Seattle-Northwest Securities Corporation - Financial Advisor
  • Foster Pepper - Legal Advisor


  • Hawkins Delafield & Wood LLP - Legal Advisor
  • Taylor-DeJongh - Financial Advisor
  • Booz Allen Hamilton - Financial Advisor


Duration / Status

The Pontoon Construction project began in February 2011 and concluded in March 2015.

The new Floating Bridge began construction in late 2011 and opened in spring 2016. The demolition of the old bridge and other remaining construction are expected to be complete by the end of 2016. The Eastside Transit and HOV Project began construction in spring 2011 and was completed in September 2015.

SR-520: I-5 to Lake Washington (West Approach Bridge North) began construction in fall 2014 and will open in summer 2017.

SR-520: I-5 to Lake Washington (Rest of the West) is scheduled to begin construction in 2018:

  • Montlake Phase - Begin 2018; duration 4-5 years
  • Portage Bay Phase - Begin 2020-2022; duration 6 years
  • Montlake Cut Crossing Phase - Begin 2024; duration 3 years
TIFIA Credit Assistance

Direct Loan - $300 million

Financial Status / Financial Performance

TIFIA loan agreement was executed on October 25, 2012

  • The new Floating Bridge is designed to withstand a 1,000-year earthquake event and windstorms up to 89 mph.
  • The Washington State Legislature authorized the collection of tolls on the existing Floating Bridge beginning in December 2011 to help fund and finance the construction of its replacement. Tolls are now collected on the new bridge to repay bonds and contribute to its operations and maintenance. Toll collection is all-electronic and toll rates vary by day and time of travel.
Related Links / Articles

WSDOT Project Website

Pontoon Construction Project: Project Management Plan


Amy Arnis
Assistant Secretary for Financial Administration
Chief Financial Officer
Washington State Department of Transportation
Tel: (360) 705-7000

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