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SR 520 Program - Costs, Funding and Tolling

Major transportation projects often require innovative and complex funding solutions. The SR 520 Bridge Replacement and HOV Program is no different. This page presents an overview of how the Washington State Department of Transportation plans to finance the construction of a new, safer floating bridge and improvements along SR 520 from I-5 in Seattle to I-405 in Bellevue.

What is the program’s budget?

In 2009, the Washington State Legislature set a program budget cap of $4.65 billion for reconstructing SR 520. The Legislature has authorized funding for some, but not all, of the highway’s planned improvements. The funded budget, revised to $2.9 billion in 2014, covers construction of a new floating bridge and landings, all needed bridge pontoons, an upgraded Eastside corridor, and the north half of a new west approach bridge in Seattle. 

In January 2015, WSDOT announced an updated cost of $1.57 billion for constructing the corridor’s remaining, unfunded elements in Seattle. The updated cost estimate for all program improvements, from I-5 in Seattle to I-405 in Bellevue, is $4.47 billion – about $180 million below the legislative budget cap of $4.65 billion (set in 2009).

West side cost estimates - 2010, 2012 and 2014 comparison

View a graphic (pdf 1.6 mb) comparing west side cost estimates in 2010, 2012 and 2014, or see additional background materials (pdf 338 kb) on the SR 520 program’s budget and cost estimate.

Cost estimates are developed with the WSDOT Cost Estimate Validation Process (CEVP®). View more information about CEVP and Cost Risk Assessment.

The corridor’s remaining, unfunded improvements in Seattle include:

  • A new Portage Bay Bridge.
  • A new west approach bridge for eastbound traffic.
  • Two freeway-overpass lids.
  • An extension from Montlake to I-5 of a regional bicycle and pedestrian path.
  • A second bascule bridge over the Montlake Cut.

What is currently funded?

The $2.9 billion construction budget authorized by the Legislature pays for:

  • Constructing a new, safer, six-lane floating bridge with a cross-lake bicycle and pedestrian path from Seattle to Bellevue.
  • Building 77 bridge pontoons at a new facility built in Grays Harbor and an existing facility in Tacoma.
  • Constructing the Eastside Transit and HOV Project, including two median transit stops, three community-connecting highway lids, new HOV lanes, and large-diameter culverts beneath the highway to aid fish migration.
  • Building the north (westbound) half of the new west approach bridge, which will help connect six lanes of traffic from the Montlake interchange to the new floating bridge.
  • Mitigating the program’s environmental impacts within the corridor.
  • Continuing design work for the remaining, unfunded elements of the west side of the corridor.

How will WSDOT pay for the SR 520 Bridge Replacement and HOV Program?

The state Legislature has secured a variety of state and federal funding sources, including tolling the existing SR 520 floating bridge, to help pay for the SR 520 construction program.

SR 520 program legislative budget cap (set in 2009)

$4.65 B

SR 520 program cost estimate


$4.47 B

Funding received to date


$2.9 B

    State funding (2003 Nickel and 2005 TPA)

*$0.59 B


    Federal funding

$0.2 B


    SR 520 Account (tolling and future federal funding)

$1.65 B


    Federal TIFIA loan

$0.30 B


    Deferred sales tax

$0.16 B

Unfunded need (based on 2014 CEVP® cost estimate)


$1.57 B

*Includes $10 million authorized in 2014 by ESSB 6001

Supplemental documents

Cost accountability: 1997 to 2015

Construction activities continue on Lake Washington, where the new floating bridge, just north of the existing bridge, continues to extend west toward Seattle.

Since 1997, WSDOT has invested nearly $2.1 billion on efforts to replace the aging SR 520 floating bridge and build other corridor upgrades. The funds have enabled substantial progress on corridor planning, preliminary engineering, design, environmental review, right-of-way purchases, and construction of new SR 520 bridge pontoons, Eastside transit and HOV improvements, and components of the new SR 520 floating bridge.

The Legislature has established a program limit of $4.65 billion. As of January 2015, the SR 520 Program had spent $2.07 billion, or approximately 45 percent of the program cost limit. Additionally, $22 million was spent on the Trans-Lake Study, prior to 2003. 

Financial 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.  The SR 520 program produces monthly construction progress reports and financial updates.

Trans-Lake Washington Study (1997-2003)

$22 M


- Evaluated multiple options for a new Lake Washington crossing and decided on a new SR 520 floating bridge.


SR 520 Bridge Replacement and HOV Program

$2.077 B

Preliminary engineering

$380.2 M


- 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

$127.4 M


- Purchased properties necessary for construction or mitigation.



$1.57 B


- Continued construction on Eastside, floating bridge and pontoon projects.


Total expenditures to date (as of January 2015)

$2.077 B

A helpful summary of expenditures is posted in the Program Library, under "Finance reports."

SR 520 and tolls

Tolling on the SR 520 bridge across Lake Washington began Dec. 29, 2011.

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 will be photographed and they will be able to post-pay within 72 hours or wait to receive a bill in the mail.

How were toll rates set?
Washington State Transportation Commission set toll rates following the Washington Administrative Code process. Tolls on SR 520 vary by the day and time of travel.

What will the SR 520 tolls pay for?
Tolls collected on SR 520 pay for highway improvements, as well as operations and maintenance, debt service, future repairs, insurance, and deferred sales tax.

Was the original SR 520 bridge tolled?
Yes, the SR 520 bridge was tolled from the time it was completed in August 1963, until it was paid off in June 1979. The tolls generated approximately $60 million.

For more information, visit SR 520 tolling.

SR 520 bond sale information

Washington State bonds will be sold in the public markets. Announcements of bond sales will be posted on the website of the Office of the State Treasurer. Underwriters, if any, will be identified at that time. More information can be found here:

The state has no role in administering or interpreting the application of the EB-5 immigrant investor program.

This section is in no way meant to be an endorsement of the EB-5 immigrant investor program. More information about the EB-5 program can be found here: EB-5 Immigrant Investor Program.