SR 520 Bridge Replacement and HOV Program - Budget and performance

Updated June 2020

SR 520 budget highlights

  • Legislative spending cap for SR 520: $4.65 B
  • Estimated cost, all planned improvements: $4.51 B
  • Funding authorized to date: $4.51 B

Major transportation projects often require innovative and complex funding solutions. The SR 520 Bridge Replacement and HOV Program is no exception. This page describes how WSDOT is financing the construction of a new, safer floating bridge and other corridor improvements. Here you also will find updated information and useful links for measuring how the construction program is meeting its financial, operational and regulatory goals.

SR 520 budget overview

What is funded and constructed?
The $4.51 billion in SR 520 funding authorized by the Legislature pays for these completed projects:

What is funded and under construction?
The corridor's remaining, funded improvements in Seattle are detailed on our Rest of the West webpage. Currently under construction is the Montlake Project, the first phase of our west side improvements. Montlake Project elements include:

  • A new West Approach Bridge South for carrying eastbound traffic from Seattle to the new floating bridge.
  • An improved interchange and landscaped highway lid in Montlake, with a regional transit hub and direct-access ramps for buses and carpools.
  • A pedestrian land bridge over SR 520, east of the Montlake lid.

What is funded and not yet under construction?

  • A reversible transit / HOV lane and ramps connecting SR 520 and Seattle's I-5 / Mercer Street interchange via the I-5 express lanes (construction scheduled to start in summer 2021).
  • A new, six-lane Portage Bay Bridge, including an extension from Montlake to I-5 of SR 520’s regional bicycle and pedestrian path.
  • A landscaped highway lid in Seattle's Roanoke neighborhood, with local and regional bike/pedestrian connections.
  • A wide, landscaped bike-pedestrian crossing over I-5 along East Roanoke Street.
  • A second bascule bridge over the Montlake Cut.

Revenue sources and cost estimates

How WSDOT is paying for the SR 520 Bridge Replacement and HOV Program

  • SR 520 program legislative spending cap (set in 2009): $4.65 B
  • SR 520 program cost estimate: $4.51 B
  • Funding authorized to date: $4.51 B*
  • State funding (primarily gas tax): $0.54 B
  • State funding (Connecting Washington account): $1.64 B
  • SR 520 Account (tolling and future federal funding): $1.67 B
  • Federal TIFIA loan: $0.30 B
  • Other federal funding: $0.20 B
  • Deferred sales tax: $0.16 B

* Includes $1.64 billion in new revenue authorized in 2015 via ESSB 5988; $14 million authorized in 2015 via 2ESHB 1299; and $10 million in existing agency resources authorized in 2014 via ESSB 6001.

How does WSDOT calculate the cost of its construction projects?
Cost estimates are developed with the WSDOT Cost Estimate Validation Process (CEVP®). View more information about CEVP and Cost Risk Assessment here.

Program performance and accountability

Who oversees the performance of the SR 520 construction program?
Financial and operational oversight is provided by WSDOT management, the Governor's Office of Financial Management, the Office of the State Treasurer, the Washington State Legislature and the Federal Highway Administration.

What has been spent so far on SR 520 construction?
Since 1997, WSDOT has invested more than $2.8 billion - approximately 62 percent of the program's $4.65 billion legislative spending cap – on work to replace the aging SR 520 floating bridge and make other corridor upgrades. Additionally, $22 million was spent on the Trans-Lake Study.

Besides construction, the program's funds supported corridor planning, preliminary engineering, design, environmental review, and right-of-way purchases. We've made substantial progress. All bridge pontoons and Eastside improvements were completed in early 2015, the new floating bridge opened to traffic in spring 2016, and the West Approach Bridge North opened to traffic in summer 2017.

SR 520 expenditures to date (through November 2019)

Trans-Lake Washington Study (1997-2003)


Early regional study



- Evaluated multiple options for a new Lake Washington crossing and decided on a new SR 520 floating bridge. (*not part of SR 520 program budget)


SR 520 Bridge Replacement and HOV Program


Preliminary engineering



- Addressed legislative requirements for reports, studies, and/or processes.
- Produced nine environmental documents needed for construction permits.
- Completed preliminary or conceptual design for the SR 520 corridor, pontoon casting facility, and pontoons.


Right of way



- Purchased properties necessary for construction or mitigation.





- Completed construction of Eastside, floating bridge, West Approach Bridge North, and pontoon projects.


Expenditures grand total (through November 2019)


Finance reports

Below is a catalog of finance reports i that cover SR 520 program expenditures, tolling and traffic performance, revenue forecasts, and other data.

Are there other sources for getting SR 520 financial information?
Yes - WSDOT provides a variety of tools and resources to ensure transparency and public accountability for the SR 520 program information. These include:

Tolling the SR 520 floating bridge

When did tolling start on SR 520?
Tolling on the old SR 520 bridge across Lake Washington began right after the bridge was completed in August 1963, and continued until the construction bonds were paid off in June 1979. The tolls generated approximately $60 million in revenue. Tolling restarted on the old bridge on Dec. 29, 2011, to help fund construction of the new floating bridge. 

Does the new floating bridge have tolls?
Yes, tolling on the new bridge began when it opened in spring 2016.

What do SR 520 tolls pay for?
Tolls collected on SR 520 help pay off bonds issued to reconstruct the highway. Tolls also pay for SR 520 operations and maintenance, debt service, future repairs, insurance, and deferred sales tax.

What are toll rates on SR 520?
SR 520 bridge toll rates vary by time of day and on weekends. A Good To Go! account is the cheapest way to pay for tolls, or you can pay by mail for an additional $2. Vehicles with more than two axles pay a higher, prorated toll rate. Tolls are collected in both directions on the bridge.

How do drivers pay tolls on SR 520?
The SR 520 corridor uses all-electronic tolling, meaning no toll booths and no stopping to pay. Tolls are collected electronically from those with a Good To Go! account as vehicles travel at highway speeds. The license plates of drivers without an account are photographed – these drivers can pay online within 72 hours of crossing or wait to receive a bill in the mail.

How were toll rates set?
The Washington State Transportation Commission sets toll rates following the Washington Administrative Code process. Tolls on SR 520 vary by the day and time of travel.
How long will SR 520 tolling last?
SR 520 tolling is projected to generate approximately $1.2 billion. When the Legislature authorized SR 520 tolling it did not specify an end date. Tolls will continue on the bridge at least until the construction bonds are paid off. Revenue from tolling the SR 520 bridge will be used only as authorized by the Legislature for bond payments, preservation, operations and maintenance within the corridor.

For more information, visit the SR 520 tolling page.

SR 520 bond sales

Washington State bonds for the SR 520 program are sold in the public markets. Announcements of bond sales are posted on the website of the Office of the State Treasurer. Underwriters, if any, are identified at that time.

The state has no role in administering or interpreting the application of the federal EB-5 immigrant investor program and any SR 520 bonds sold under that program. This section is in no way meant to be an endorsement of the EB-5 immigrant investor program.