:Washington State Route 520

{{Infobox road

|state=WA

|type=SR

|route=520

|map={{maplink-road|from=Washington State Route 520.map}}

|map_custom=yes

|map_notes=Map of Seattle and the Eastside, with SR 520 highlighted in red

|map_alt=A map of the area east of Seattle, showing urbanized areas and major highways. A red line running horizontally marks the route of State Route 520.

|spur_type=I

|spur_of=5

|section=720

|length_mi=12.82

|length_ref={{WSDOT State Highway Log |year=2016 |pages=1525–1532 |link=yes |style=alt |access-date=August 29, 2017}}

|length_round=2

|established=1964{{cite web |url=http://apps.leg.wa.gov/RCW/default.aspx?cite=47.17.720 |title=47.17.720: State route No. 520 |year=1970 |work=Revised Code of Washington |publisher=Washington State Legislature |access-date=July 17, 2017 |url-status=live |archive-url=https://web.archive.org/web/20160304022645/http://apps.leg.wa.gov/RCW/default.aspx?cite=47.17.720 |archive-date=March 4, 2016 |df=mdy-all }}

|direction_a=West

|terminus_a={{jct|state=WA|I|5}} in Seattle

|junction={{jct|state=WA|I|405}} in Bellevue

|direction_b=East

|terminus_b={{jct|state=WA|SR|202}} in Redmond

|county=King

|previous_type=WA

|previous_route=519

|next_type=WA

|next_route=522

}}

State Route 520 (SR 520) is a state highway and freeway in the Seattle metropolitan area, part of the U.S. state of Washington. It runs {{convert|13|mi|km|0}} from Seattle in the west to Redmond in the east. The freeway connects Seattle to the Eastside region of King County via the Evergreen Point Floating Bridge on Lake Washington. SR 520 intersects several state highways, including Interstate 5 (I-5) in Seattle, I-405 in Bellevue, and SR 202 in Redmond.

The original floating bridge was opened in 1963 as a replacement for the cross-lake ferry system that had operated since the late 19th century. In 1964, SR 520 was designated as a freeway connecting I-5 to I-405. An extension to Redmond was proposed later in the decade. In the 1970s and 1980s, sections of the freeway between Bellevue and Redmond were opened to traffic, replacing the temporary designation of SR 920.

Since the 1990s, SR 520 has been expanded with high-occupancy vehicle lanes (HOV lanes) and new interchanges to serve the Overlake area. In 2016, the original Evergreen Point Floating Bridge was replaced by a wider bridge, as part of a multibillion-dollar expansion program that is scheduled to be completed in the 2020s. The program also includes the construction of new bus infrastructure at Montlake and on the Eastside, as well as a bicycle and pedestrian path along most of the highway's length.

Route description

File:SR 520 eastbound at SR 202, Redmond, Washington.jpg in Downtown Redmond|alt=A four-lane freeway separated from oncoming traffic by a concrete barrier. A sign in the background indicates that the exit for State Route 202 is approaching.]]

SR 520 begins at an interchange with I-5 in northern Seattle near Roanoke Park. The interchange provides access to both directions of I-5 as well as a westbound off-ramp to Harvard Avenue and Roanoke Street.{{cite web |date=March 14, 2017 |title=SR 5 – Exit 168A/B: SR 520/Roanoke St/Boylston Ave |url=http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X168.pdf |publisher=Washington State Department of Transportation |access-date=July 17, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902102642/http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR005/005X168.pdf |archive-date=September 2, 2017 |df=mdy-all }} SR 520 travels east across the south end of Portage Bay and its wetlands on the Portage Bay Viaduct, entering the Montlake neighborhood. In Montlake, the highway intersects Montlake Boulevard (SR 513) and Lake Washington Boulevard just south of the University of Washington campus and Husky Stadium.{{google maps |title=State Route 520 |url=https://www.google.com/maps/dir/47.6394697,-122.3224992/47.6699178,-122.1070137/@47.6495755,-122.3548381,11z/am=t/data=!3m1!4b1!4m2!4m1!3e0 |access-date=July 17, 2017}} The freeway gains a set of HOV lanes and continues east on a pair of causeways through the marshlands of Union Bay and Foster Island, at the north end of the Washington Park Arboretum.{{cite news |last=DeMay |first=Daniel |date=August 25, 2017 |title=SR 520 bridge closed this weekend |url=http://www.seattlepi.com/local/transportation/article/SR-520-bridge-closed-this-weekend-11958385.php |work=Seattle Post-Intelligencer |access-date=December 17, 2017 |url-status=live |archive-url=https://web.archive.org/web/20171201233341/http://www.seattlepi.com/local/transportation/article/SR-520-bridge-closed-this-weekend-11958385.php |archive-date=December 1, 2017 |df=mdy-all }}{{cite web |date=April 2017 |title=Key features of the West Approach Bridge North Project upon completion |url=http://www.wsdot.wa.gov/NR/rdonlyres/9E336155-643F-4A96-BC6F-28B8BCA3684E/0/2017_SR520_WABN_KeyFeatures_v2.pdf |publisher=Washington State Department of Transportation |access-date=December 31, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20171231232639/http://www.wsdot.wa.gov/NR/rdonlyres/9E336155-643F-4A96-BC6F-28B8BCA3684E/0/2017_SR520_WABN_KeyFeatures_v2.pdf |archive-date=December 31, 2017 |df=mdy-all }}

From Seattle, SR 520 crosses Lake Washington on the six-lane Evergreen Point Floating Bridge; at {{convert|7,710|ft|m}}, it is the longest floating bridge in the world.{{cite web |last=Dougherty |first=Phil |date=May 17, 2016 |title=New State Route 520 floating bridge opens to traffic on April 25, 2016. |url=http://historylink.org/File/11227 |publisher=HistoryLink |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902094541/http://historylink.org/File/11227 |archive-date=September 2, 2017 |df=mdy-all }} Tolls are collected electronically using the state's Good to Go pass or by mail, and vary based on time of day and the vehicle's number of axles. {{As of|2024}}, tolls for Good to Go users range from a minimum of $1.35 between 11:00 p.m. and 5:00 a.m. and a maximum of $4.90 during the morning and evening peak periods; tolls paid by mail are charged an additional $2.{{cite news |last=Lindblom |first=Mike |date=July 10, 2024 |title=520 bridge tolls about to increase |url=https://www.seattletimes.com/seattle-news/transportation/520-bridge-tolls-about-to-increase/ |work=The Seattle Times |accessdate=October 29, 2024}} The freeway reaches the eastern end of Lake Washington at Evergreen Point in northern Medina, where it travels under a landscaped park lid and next to a median-side bus station. After an interchange and lid at 84th Avenue Northeast in Hunts Point, SR 520 travels eastward around the northern edge of Clyde Hill in a north-facing arc, passing through the Yarrow Point lid and bus station.{{cite news |last=Kroman |first=David |date=May 9, 2023 |title=7 acres, 3 lids: Eastside cities want the state to mow the lawn |url=https://www.seattletimes.com/seattle-news/transportation/7-acres-3-lids-eastside-cities-want-the-state-to-mow-the-lawn/ |work=The Seattle Times |accessdate=May 9, 2023}} The freeway enters Bellevue, intersecting I-405 and crossing over the Eastside Rail Corridor. SR 520 continues along the north side of the Bel-Red industrial area and enters the Overlake area of Redmond.

Within Overlake, SR 520 turns north and passes under a pedestrian bridge connecting to Overlake Village station on the 2 Line, a light rail line that follows the highway.{{cite news |last=Lindblom |first=Mike |date=January 26, 2024 |title=New walk-bike bridge debugs access to Microsoft and light rail |url=https://www.seattletimes.com/seattle-news/transportation/new-walk-bike-bridge-debugs-access-to-microsoft-and-light-rail/ |work=The Seattle Times |accessdate=January 26, 2024}} The freeway then passes several office parks, including the headquarters campus of Microsoft and the Nintendo of America branch office.{{cite news |last=Romano |first=Benjamin J. |date=November 11, 2007 |title=Microsoft campus expands, transforms, inside and out |page=A1 |url=http://old.seattletimes.com/html/microsoft/2004007121_microsoft11.html |work=The Seattle Times |access-date=July 17, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170829082830/http://old.seattletimes.com/html/microsoft/2004007121_microsoft11.html |archive-date=August 29, 2017 |df=mdy-all }} To serve exits at Northeast 40th Street and Northeast 51st Street, SR 520 gains a set of collector–distributor lanes, separated from other lanes by a concrete barrier.{{cite news |last=Fujioka |first=Justin |date=October 19, 2015 |title=When sharing can be a problem |url=https://wsdotblog.blogspot.com/2015/10/when-sharing-can-be-problem.html |work=WSDOT Blog |publisher=Washington State Department of Transportation |access-date=August 28, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170829081501/https://wsdotblog.blogspot.com/2015/10/when-sharing-can-be-problem.html |archive-date=August 29, 2017 |df=mdy-all }} The freeway crosses the Sammamish River and turns east, passing to the south of the Redmond Town Center mall and Bear Creek and to the north of Marymoor Park. East of downtown Redmond, SR 520 intersects SR 202 and terminates;{{cite web |date=August 31, 2011 |title=SR 520 – Junction SR 202 |url=http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR520/520X012.pdf |publisher=Washington State Department of Transportation |access-date=December 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170212130755/https://www.wsdot.wa.gov/MapsData/tools/InterchangeViewer/pdf/SR520/520X012.pdf |archive-date=February 12, 2017 |df=mdy-all }} the road continues north as Avondale Road towards Cottage Lake. Portions of the corridor from Montlake to Downtown Redmond are also paralleled by a shared-use trail for bicycles and pedestrians.{{cite news |last=Shaw |first=Greg |date=January 27, 2015 |title=A new 520 bike trail is re-shaping the Eastside |url=http://crosscut.com/2015/01/will-new-520-corridor-bike-trail-re-shape-eastside/ |work=Crosscut.com |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20151227123448/http://crosscut.com/2015/01/will-new-520-corridor-bike-trail-re-shape-eastside/ |archive-date=December 27, 2015 |df=mdy-all }}{{cite map |date=February 2017 |title=Regional Trails in King County |url=http://aqua.kingcounty.gov/gis/web/VMC/recreation/RTMap_Feb2017.pdf |publisher=King County Parks and Recreation Division |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170901043326/http://aqua.kingcounty.gov/gis/web/VMC/recreation/RTMap_Feb2017.pdf |archive-date=September 1, 2017 |df=mdy-all }}{{cite press release |date=December 20, 2017 |title=SR 520 Trail now open across Lake Washington |url=https://www.wsdot.wa.gov/news/2017/12/20/sr-520-trail-now-open-across-lake-washington |publisher=Washington State Department of Transportation |access-date=December 26, 2017 |url-status=live |archive-url=https://web.archive.org/web/20171227025707/https://www.wsdot.wa.gov/news/2017/12/20/sr-520-trail-now-open-across-lake-washington |archive-date=December 27, 2017 |df=mdy-all }}

SR 520's entire route is designated as part of the National Highway System,{{cite map |author=Federal Highway Administration |title=National Highway System: Seattle, WA |url=https://www.fhwa.dot.gov/planning/national_highway_system/nhs_maps/washington/seattle_wa.pdf |date=September 22, 2015 |publisher=Federal Highway Administration |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170501035324/https://www.fhwa.dot.gov/planning/national_highway_system/nhs_maps/washington/seattle_wa.pdf |archive-date=May 1, 2017 |df=mdy-all }} classifying it as important to the national economy, defense, and mobility.{{cite web |title=What is the National Highway System? |url=https://www.fhwa.dot.gov/planning/national_highway_system/ |publisher=Federal Highway Administration |date=January 31, 2017 |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20120704194551/https://www.fhwa.dot.gov/planning/national_highway_system/ |archive-date=July 4, 2012 |df=mdy-all }} The State of Washington also designates the SR 520 corridor as a Highway of Statewide Significance,{{cite web |title=Transportation Commission List of Highways of Statewide Significance |url=https://www.wsdot.wa.gov/sites/default/files/2006/03/16/HSSlist2009mod2.pdf |publisher=Washington State Transportation Commission |date=July 26, 2009 |access-date=August 31, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20130724190950/http://www.wsdot.wa.gov/NR/rdonlyres/50EC9EB9-DB3D-4823-B5D2-5348409FB8CE/0/HSSlist2009mod2.pdf |archive-date=July 24, 2013 |df=mdy-all }} a category of highways that connect major communities throughout the state.{{cite web |title=Highways of Statewide Significance |url=http://www.wsdot.wa.gov/planning/HSS/Default.htm |publisher=Washington State Department of Transportation |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170822140657/https://www.wsdot.wa.gov/planning/HSS/Default.htm |archive-date=August 22, 2017 |df=mdy-all }} SR 520 is maintained by the Washington State Department of Transportation (WSDOT), which conducts an annual survey on the state's highways to measure traffic volume in terms of annual average daily traffic. In 2016, WSDOT calculated that 80,000 vehicles traveled on SR 520 near its interchange with SR 202 in Redmond and 47,000 vehicles used it at SR 513 in Seattle, the highest and lowest traffic counts along the highway, respectively.{{cite web |year=2017 |title=2016 Annual Traffic Report |page=200 |url=http://www.wsdot.wa.gov/mapsdata/travel/pdf/Annual_Traffic_Report_2016.pdf |publisher=Washington State Department of Transportation |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170812180326/http://www.wsdot.wa.gov/mapsdata/travel/pdf/Annual_Traffic_Report_2016.pdf |archive-date=August 12, 2017 |df=mdy-all }} The highway is noted for its lack of a "reverse commute", with roughly equal amounts of traffic in both directions during peak periods.{{cite book |date=June 2011 |title=SR 520, I-5 to Medina: Bridge Replacement and HOV Project Final Environmental Impact Statement |oclc=750115709 |chapter=Chapter 1: Introduction to the Project |pages=6–7 |chapter-url=http://www.wsdot.wa.gov/NR/rdonlyres/1C10560E-A9AE-499D-9BD8-5E580315D5AA/0/SR520_FEIS_Chapter1.pdf |publisher=Washington State Department of Transportation |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902102003/http://www.wsdot.wa.gov/NR/rdonlyres/1C10560E-A9AE-499D-9BD8-5E580315D5AA/0/SR520_FEIS_Chapter1.pdf |archive-date=September 2, 2017 |df=mdy-all }}{{cite news |last=Lindblom |first=Mike |date=June 4, 2002 |title=Seattle-to-Eastside trip is no longer 'reverse' commute |page=B1 |url=https://archive.seattletimes.com/archive/20020604/reverse04m/seattle-to-eastside-trip-is-no-longer-reverse-commute |work=The Seattle Times |access-date=October 30, 2017 |url-status=live |archive-url=https://web.archive.org/web/20171107002639/http://community.seattletimes.nwsource.com/archive/?date=20020604&slug=reverse04m |archive-date=November 7, 2017 |df=mdy-all }}

History

=Ferries and proposed floating bridge=

New towns along the eastern shore of Lake Washington were established in the late 19th century and initially served by steamship ferries, bringing passengers and goods to and from Seattle.{{cite web |last=Stein |first=Alan J. |date=October 25, 1998 |title=Kirkland — Thumbnail History |url=http://www.historylink.org/File/208 |publisher=HistoryLink |access-date=July 17, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170901113741/http://www.historylink.org/File/208 |archive-date=September 1, 2017 |df=mdy-all }} By 1913, the steam ferry Leschi was transporting automobiles and pedestrians between Seattle and the docks in Bellevue, Kirkland, and Medina.{{cite web |last=Stein |first=Alan J. |date=February 10, 2013 |title=Leschi, the first auto ferry in Western Washington, is launched on Lake Washington on December 6, 1913. |url=http://www.historylink.org/File/2040 |publisher=HistoryLink |access-date=July 17, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170901111850/http://www.historylink.org/File/2040 |archive-date=September 1, 2017 |df=mdy-all }} In 1940, the Lake Washington Floating Bridge was opened between Seattle and Mercer Island, carrying the Sunset Highway (later I-90) from Seattle towards Bellevue and the Eastside. The new bridge allowed the Eastside to develop rapidly into bedroom communities in the 1940s and 1950s;{{cite news |last=Reynolds |first=Peggy |date=November 26, 1990 |title='The biggest thing afloat' |page=A5 |url=https://archive.seattletimes.com/archive/19901126/1106244/the-biggest-thing-afloat |work=The Seattle Times |access-date=July 19, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170901112048/http://community.seattletimes.nwsource.com/archive/?date=19901126&slug=1106244 |archive-date=September 1, 2017 |df=mdy-all }} the bridge also replaced the ferry system, which ceased operation in 1950, shortly after the removal of tolls on the bridge.{{cite news |last=Whitely |first=Peyton |date=April 16, 1998 |title=Before the Bridge: From 1870 to 1950, most Eastsiders who wanted to cross Lake Washington traveled by ferry |page=B3 |url=https://archive.seattletimes.com/archive/19980416/2745498/before-the-bridge |work=The Seattle Times |access-date=July 19, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170901115101/http://community.seattletimes.nwsource.com/archive/?date=19980416&slug=2745498 |archive-date=September 1, 2017 |df=mdy-all }}{{cite news |last1=Boswell |first1=Sharon |last2=McConaghy |first2=Lorraine |date=June 16, 1996 |title=A bridge to the future |url=http://old.seattletimes.com/special/centennial/june/bridge.html |work=The Seattle Times |access-date=July 19, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170321051151/http://old.seattletimes.com/special/centennial/june/bridge.html |archive-date=March 21, 2017 |df=mdy-all }}

In the late 1940s, the state government conducted a feasibility study for a second floating bridge across Lake Washington, in response to increased traffic on the Mercer Island bridge.{{cite news |date=August 31, 1949 |title=State Orders Survey for 2nd Lake Bridge |page=1 |work=The Seattle Times}} In 1953, the Washington State Legislature approved the construction of a second floating bridge, using past and future tolls to fund its construction.{{cite book |date=March 18, 1953 |title=Session Laws of the State of Washington, 1953 |chapter=Chapter 192: Additional Bridge Across Lake Washington |pages=413–414 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1953c192.pdf |publisher=Washington State Legislature |access-date=December 17, 2017 |url-status=live |archive-url=https://web.archive.org/web/20171218034708/http://leg.wa.gov/CodeReviser/documents/sessionlaw/1953c192.pdf |archive-date=December 18, 2017 |df=mdy-all }}{{cite web |year=2010 |title=HAER No. WA-201: Evergreen Point Floating Bridge (Governor Albert D. Rosellini Bridge—Evergreen Point) |pages=7–9 |url=https://cdn.loc.gov/master/pnp/habshaer/wa/wa0800/wa0883/data/wa0883data.pdf |work=Historic American Engineering Record |publisher=National Park Service |access-date=July 19, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170216064427/https://cdn.loc.gov/master/pnp/habshaer/wa/wa0800/wa0883/data/wa0883data.pdf |archive-date=February 16, 2017 |df=mdy-all }} The west end of the floating bridge was to connect to the Everett–Seattle tollway (later I-5) at Roanoke Street, south of the planned Ship Canal Bridge, as well as the proposed Empire Way Expressway (later the R.H. Thompson Expressway) at Montlake.{{cite news |date=December 12, 1954 |title=Details Of Multimillion Project Told |page=1 |work=The Seattle Times}}{{cite news |date=December 27, 1957 |title=City Studies Analysis Of 5 Routes For Lake Bridge |page=1 |work=The Seattle Times}} The east end was to connect to the planned north–south freeway bypass of the Seattle area (later I-405), with an optional connection to the Stevens Pass Highway.{{cite news |last=Willix |first=Douglas |date=November 11, 1957 |title=New Lake-Span Problems |page=12 |work=The Seattle Times}} Two alignments for the floating bridge were considered in the late 1950s: a Sand Point–Kirkland, favored by the City of Seattle; and an Evergreen Point crossing, favored by the state government and the U.S. Navy, which operated Naval Air Station Sand Point. The state government initially chose the Montlake–Evergreen Point alignment in 1954, intending to begin construction in 1955,{{cite news |date=August 3, 1954 |title=Montlake-Evergreen Point Route Picked For 2nd Lake Bridge; Construction To Begin In 8 Months |page=1 |work=The Seattle Times |agency=United Press International}} but the alignment dispute delayed a final decision until December 1956.{{cite news |last=Hittle |first=Leroy |date=December 12, 1956 |title=Highway Board View Is Indorsed |page=1 |work=The Seattle Times |agency=Associated Press}}{{cite web |last=Dougherty |first=Phil |date=June 26, 2015 |title=Evergreen Point Floating Bridge opens on August 28, 1963. |url=http://www.historylink.org/File/690 |publisher=HistoryLink |access-date=August 26, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170827124455/http://www.historylink.org/File/690 |archive-date=August 27, 2017 |df=mdy-all }} Citizen groups from the Montlake area protested the decision, but were largely ignored by the project's citizen committee.{{cite news |date=December 10, 1956 |title=Montlake Club Protests Proposal For Lake Bridge |page=25 |work=The Seattle Times}}

=Opening of floating bridge and freeway=

File:SR 520 under construction, 1963 (15980299986).jpg

Construction of the Evergreen Point Floating Bridge began on August 29, 1960, and assembly of the bridge's pontoons began the following year.{{cite news |date=February 19, 1961 |title=Firm Prepares To Build Pontoons For Lake Bridge |page=26 |work=The Seattle Times}} The bridge and its approach highways, connecting the main branch of Primary State Highway 1 in Seattle to its Eastside branch near Bellevue, were added to the state highway system in March 1961.{{cite news |date=March 26, 1961 |title=Senate Passes 2 Highway Bills |page=41 |work=The Seattle Times |agency=Associated Press}}{{cite book |date=April 3, 1961 |title=Session Laws of the State of Washington, 1961 extraordinary session |chapter=Chapter 21: Highways |page=2617 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1961ex1c21.pdf |publisher=Washington State Legislature |access-date=August 28, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170202151448/http://leg.wa.gov/CodeReviser/documents/sessionlaw/1961ex1c21.pdf |archive-date=February 2, 2017 |df=mdy-all }} Construction of the western approach, an expressway between the Roanoke Interchange, Portage Bay, Montlake, and the Washington Park Arboretum, began in early 1962.{{cite news |date=April 24, 1962 |title=Section of 10th Ave. E. To Be Closed |page=29 |work=The Seattle Times}} The eastern approach was constructed between 1962 and 1963, connecting the bridge to Medina, Secondary State Highway 2A in southern Houghton, and Northup Way—a local road that continued east towards Redmond.{{cite news |last=Barr |first=Robert A. |date=September 19, 1962 |title=Work Goes Fast: 2nd Lake Span Spurting Ahead |page=3 |work=The Seattle Times}}{{cite news |date=February 19, 1963 |title=Evergreen Span, Northrup Way To Be Linked |page=9 |work=The Seattle Times}}

The Evergreen Point Floating Bridge opened on August 28, 1963, along with the Roanoke Expressway, part of the Seattle Freeway,{{cite news |date=August 28, 1963 |title=Rosellini Snips Ribbon to Open New Floating Bridge |page=C |work=The Seattle Times}} and the eastern approach to Houghton and Bellevue up to a temporary interchange with 104th Avenue Northeast.{{cite news |date=August 25, 1963 |title=Traffic Routes to the Evergreen Point Floating Bridge |page=4 |work=The Seattle Times}} The bridge and its approaches, constituting a state highway, were re-designated as Sign Route 520 (later SR 520) under the new state highway numbering system adopted in 1964.{{cite web |last=Prahl |first=C. G. |date=December 1, 1965 |title=Identification of State Highways |url=https://www.wsdot.wa.gov/sites/default/files/2005/04/26/Identification-of-state-highways.pdf |publisher=Washington State Highway Commission |access-date=August 26, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170217112902/https://www.wsdot.wa.gov/NR/rdonlyres/6836215D-E301-43F3-895A-472BD2FDE86A/0/Identification.pdf |archive-date=February 17, 2017 |df=mdy-all }}{{cite news |date=January 26, 1964 |title=To End Confusion: Highways Given Different Numbers |page=24 |work=The Seattle Times}} SR 520 would use a temporary route on Northup Way (Northeast 20th Street) and Bel-Red Road between Bellevue and SR 202 in Redmond until the planned freeway was completed by the late 1970s.{{cite news |date=September 11, 1966 |title=Hearing Set On Extending Highway 520 |page=42 |work=The Seattle Times}}{{cite map |author=United States Geological Survey |date=1975 |title=Seattle, Wash. |url=https://ngmdb.usgs.gov/img4/ht_icons/Browse/WA/WA_Seattle_243649_1975_100000.jpg |scale=1:100,000 |type=Topographic map |publisher=United States Geological Survey |access-date=December 26, 2017 |url-status=live |archive-url=https://web.archive.org/web/20171227023631/https://ngmdb.usgs.gov/img4/ht_icons/Browse/WA/WA_Seattle_243649_1975_100000.jpg |archive-date=December 27, 2017 |df=mdy-all }}{{cite map |author=United States Geological Survey |date=1982 |title=Bellevue North, Washington |url=https://ngmdb.usgs.gov/img4/ht_icons/Browse/WA/Bellevue_North_K47122F1.jpg |scale=1:25,000 |type=Topographic map |publisher=United States Geological Survey |access-date=December 26, 2017 |url-status=live |archive-url=https://web.archive.org/web/20171227122557/https://ngmdb.usgs.gov/img4/ht_icons/Browse/WA/Bellevue_North_K47122F1.jpg |archive-date=December 27, 2017 |df=mdy-all }} A section of SR 520 between the Evergreen Point Bridge toll plaza and 104th Avenue Northeast was expanded in 1973 to accommodate a bus-only lane at the request of Metro Transit, which had begun operating express buses over the bridge.{{cite news |date=August 30, 1973 |title=East Side bus-only lane to open |page=F5 |work=The Seattle Times}}

=Extension to Redmond=

The Northup Interchange, where SR 520 intersects I-405, was opened on November 22, 1966.{{cite news |last=Barr |first=Robert A. |date=November 9, 1966 |title=2 Interchanges On East Side Freeway To Open Nov. 22 |page=1 |work=The Seattle Times}} The highway was also extended east from 104th Avenue Northeast to 124th Avenue Northeast, serving the Bel-Red industrial area. The state government announced plans in 1968 to begin construction on the remaining freeway to Redmond, via a northeastward course through the Overlake area and across Marymoor Park.{{cite news |last=Barr |first=Robert A. |date=August 4, 1968 |title=Plans Announced For Redmond Freeway |page=17 |work=The Seattle Times}} Construction of a {{convert|1.3|mi|km|adj=mid|-long}} segment between 124th Avenue Northeast and 148th Avenue Northeast in Overlake began in February 1972 and was completed in December 1973.{{cite news |date=January 30, 1972 |title=Work begins soon on Redmond-Seattle link |page=D20 |work=The Seattle Times}}{{cite news |date=December 10, 1973 |title=Four-lane highway link opens |page=D15 |work=The Seattle Times}}

The planned route of SR 520 along the north side of Marymoor Park in Redmond was given the temporary designation of SR 920 in 1975.{{cite book |date=April 5, 1975 |title=Session Laws of the State of Washington, 1975 |chapter=Chapter 63: State Highways—Route Designations |page=131 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1975c63.pdf |publisher=Washington State Legislature |access-date=August 28, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170127210733/http://leg.wa.gov/CodeReviser/documents/sessionlaw/1975c63.pdf |archive-date=January 27, 2017 |df=mdy-all }} The two-lane expressway, connecting West Lake Sammamish Parkway (SR 901) and SR 202, was opened in July 1977 after several months of construction.{{cite news |date=July 14, 1977 |title=New Redmond bypass will open tomorrow |page=D5 |work=The Seattle Times}}{{cite news |date=May 13, 1976 |title=Work begins next week on Redmond-bypass bridge |page=D9 |work=The Seattle Times}} Completion of the last segment of SR 520, between 148th Avenue Northeast and SR 920, was given priority by Eastside cities and civic groups in the mid-1970s.{{cite news |date=August 11, 1976 |title=Extension of Highway 520 to Redmond to be discussed |page=H2 |work=The Seattle Times}} However, the City of Bellevue asked that the state government build a reversible bus lane on the Evergreen Point Floating Bridge before completing the last segment, due to increased traffic on the bridge.{{cite news |last=Sufia |first=David |date=November 24, 1976 |title=Bellevue's transit-land request makes Redmond mayor see red |page=D4 |work=The Seattle Times}} The City of Redmond opposed the request, leading to a dispute between the two cities that was later resolved with a compromise to place completion of SR 520 ahead of the bus lane.{{cite news |last=Sufia |first=David |date=December 15, 1976 |title=Two-city 'pact' on highway? |page=H7 |work=The Seattle Times}}

The state government approved funding for the Redmond project in 1977, extending SR 520 by {{convert|2.65|mi|km}} at an estimated cost of $10 million (equivalent to ${{Inflation|US-GDP|10|1977|r=0}} million in {{Inflation-year|US-GDP}} dollars{{inflation-fn|US-GDP}}), funded using part of a statewide gasoline tax increase of two cents per gallon.{{cite news |last=Daniel |first=Linda |date=June 29, 1977 |title=Gas tax: That 2 cents a gallon will make Redmond travel easier |page=H1 |work=The Seattle Times}} Contract bidding for the last segment was halted in 1978 by a lawsuit filed by a group of Eastside residents in opposition to the freeway, claiming that its environmental impact had been improperly assessed.{{cite news |last=Wilson |first=Marshall |date=October 18, 1978 |title=Lawsuit postpones Highway 520 bids |page=H1 |work=The Seattle Times}} U.S. District Judge Morell Edward Sharp ruled in favor of the state government in March 1979, allowing for the bid to be awarded to a contractor.{{cite news |date=March 13, 1979 |title=State plans to OK funds for 520 |page=A9 |work=The Seattle Times}} The segment was opened to traffic on December 18, 1981.{{cite news |last=Case |first=Rebecca |date=December 18, 1981 |title=Redmond 520 link opens today |page=A1 |work=Journal-American |location=Bellevue, Washington}} The SR 920 designation was removed from the state highway system in 1985, and the section was re-signed as part of SR 520.{{cite book |date=April 25, 1985 |title=Session Laws of the State of Washington, 1985 |chapter=Chapter 177: State Highways Routes Revised |page=674 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1985c177.pdf |publisher=Washington State Legislature |access-date=August 28, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170127112310/http://leg.wa.gov/CodeReviser/documents/sessionlaw/1985c177.pdf |archive-date=January 27, 2017 |df=mdy-all }} A traffic signal at the intersection of SR 520 and Northeast 51st Street remained in place until 1986, when it was replaced with an interchange.{{cite news |date=March 11, 1985 |title=Eastside Briefly |page=D1 |work=The Seattle Times}}{{cite news |date=September 8, 1986 |title=Eastside Briefly: N.E. 51st St. traffic temporarily rerouted |page=B1 |work=The Seattle Times}}

=Freeway widening and new interchanges=

The completion of SR 520 spurred new development in Downtown Redmond and the Overlake area, contributing to major traffic congestion on the freeway.{{cite news |last=Tizon |first=Alex |date=June 3, 1987 |title=City officials want to ease congestion on Route 520 |page=H1 |work=The Seattle Times}} In 1994, the state government approved $81.1 million (equivalent to ${{Inflation|US-GDP|81|1994|r=0}} million in {{Inflation-year|US-GDP}} dollars{{inflation-fn|US-GDP}}) in highway improvements for the SR 520 corridor, including lane expansions and the addition of HOV lanes.{{cite news |last1=Norton |first1=Dee |last2=Brooks |first2=Diane |date=April 5, 1994 |title=Hwy. 522 gets slice of repair budget |page=B1 |work=The Seattle Times}} The segment from West Lake Sammamish Parkway to SR 202 was widened from two to four lanes in September 1995, and included the construction of a new bridge across the Sammamish River.{{cite news |last=Lopez Williams |first=Sarah |date=September 22, 1995 |title=520 lane fix: Help, not cure |page=B1 |work=The Seattle Times}} In late 1996, the highway's terminus at SR 202 was converted from a signalized intersection to an interchange, including an overpass connecting to Avondale Road.{{cite news |last=Lopez Williams |first=Sarah |date=October 11, 1996 |title=New lane on 520 may ease backups |page=B1 |work=The Seattle Times}} SR 520's HOV lanes between I-405 and West Lake Sammamish Parkway were opened in 1999 after a $40 million (equivalent to ${{Inflation|US-GDP|40|1999|r=0}} million in {{Inflation-year|US-GDP}} dollars{{inflation-fn|US-GDP}}) expansion project.{{cite news |last=Whitely |first=Peyton |date=October 19, 1999 |title=Upgrades on 520 nearly finished; car-pool lanes ought to improve commute |page=B1 |work=The Seattle Times}} The new lanes were restricted to two persons per vehicle, while the older HOV lanes between I-405 and the Evergreen Point Floating Bridge had a three-person requirement.{{cite news |last=Johnston |first=Steve |date=August 28, 1996 |title=Twos, threes: 520 car-pool rules are all over the road |page=B1 |work=The Seattle Times}} A new interchange was built at Northeast 40th Street in 2000 to serve the Microsoft Redmond Campus and other nearby employers, along with a set of collector–distributor lanes through the area, and ramp meters to manage traffic flow.{{cite news |last=Whitely |first=Peyton |date=October 5, 2000 |title=Hwy. 520 ramps expected to ease Redmond commute |page=B1 |work=The Seattle Times}}{{cite news |last=Bryant |first=Arlene |date=December 17, 2000 |title=Hwy. 520 adds ramp meters |page=B2 |work=The Seattle Times}} Between 1994 and 2002, portions of a multi-use pedestrian and bicycle path on the north side of the freeway were completed and opened, forming a {{convert|4.5|mi|km|adj=mid|-long}} trail from northern Bellevue to Marymoor Park in Redmond.{{cite news |last=Holt |first=Gordy |date=May 24, 2002 |title=New $2.9 million bike path links Eastside suburbs |page=B1 |work=Seattle Post-Intelligencer |url=http://seattlepi.nwsource.com:80/transportation/71725_bike24.shtml |url-status=dead |archive-url=https://web.archive.org/web/20020607214907/http://seattlepi.nwsource.com/transportation/71725_bike24.shtml |archive-date=June 7, 2002 |access-date=December 17, 2017 |df=mdy-all }}{{cite news |last=Perry |first=Nick |date=May 23, 2002 |title=Trail's final stretch along Highway 520 celebrated today |page=B4 |work=The Seattle Times}}

In the late 2000s, WSDOT completed several highway improvement projects on the segment of SR 520 between West Lake Sammamish Parkway and SR 202 in Downtown Redmond. In August 2008, a flyover ramp from westbound SR 202 to westbound SR 520 was opened to traffic, replacing a pair of onramp traffic signals.{{cite news |last=Giroux |first=Wendy |date=September 23, 2008 |title=Gregoire, officials, commuters tout success of 202 improvements |url=http://www.redmond-reporter.com/news/gregoire-officials-commuters-tout-success-of-202-improvements/ |work=Redmond Reporter |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170829082451/http://www.redmond-reporter.com/news/gregoire-officials-commuters-tout-success-of-202-improvements/ |archive-date=August 29, 2017 |df=mdy-all }}{{cite press release |date=May 2, 2007 |title=WSDOT Joins Local Leaders to Kick off New SR 202 / SR 520 Flyover Ramp |publisher=Washington State Department of Transportation |url=http://wsdot.wa.gov/News/2007/05/2_SR202Flyover.htm |url-status=dead |archive-url=https://web.archive.org/web/20091229235717/http://wsdot.wa.gov/News/2007/05/2_SR202Flyover.htm |archive-date=December 29, 2009 |access-date=August 31, 2017 |df=mdy-all }} SR 520 was widened to four lanes in each direction in 2010,{{cite news |date=June 28, 2010 |title=Drivers to get a new lane as SR 520 project reaches milestone |url=http://www.bellevuereporter.com/news/drivers-to-get-a-new-lane-as-sr-520-project-reaches-milestone/ |work=Redmond Reporter |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170901113030/http://www.bellevuereporter.com/news/drivers-to-get-a-new-lane-as-sr-520-project-reaches-milestone/ |archive-date=September 1, 2017 |df=mdy-all }} in a multi-phase project that added HOV and merge lanes, as well as reconstructed ramps at West Lake Sammamish Parkway.{{cite news |last=Roe |first=Amy |date=May 3, 2007 |title=Redmond drivers may get reprieve |page=B3 |url=http://old.seattletimes.com/html/localnews/2003691116_redroads03e.html |work=The Seattle Times |url-status=live |archive-url=https://web.archive.org/web/20170901120439/http://old.seattletimes.com/html/localnews/2003691116_redroads03e.html |archive-date=September 1, 2017 |df=mdy-all }}{{cite web |date=March 2011 |title=SR 520 – West Lake Sammamish Parkway to SR 202 – Open December 2010 |publisher=Washington State Department of Transportation |url=http://www.wsdot.wa.gov/Projects/SR520/WLakeSamPk_SR202/ |url-status=dead |archive-url=https://web.archive.org/web/20110530035043/http://www.wsdot.wa.gov/Projects/SR520/WLakeSamPk_SR202/ |archive-date=May 30, 2011 |access-date=August 31, 2017 |df=mdy-all }} In addition to the Downtown Redmond projects, a new lid-like overpass at Northeast 36th Street in Overlake was opened in 2010 to improve traffic in the area. The overpass's $30 million cost (equivalent to ${{Inflation|US-GDP|30|2010|r=0}} million in {{Inflation-year|US-GDP}} dollars{{inflation-fn|US-GDP}}) was funded mostly by Microsoft, along with contributions from the City of Redmond and federal stimulus funding.{{cite news |last=Pak |first=Samantha |date=December 16, 2010 |title=Ceremony kicks off the opening of new NE 36th Street Bridge |url=http://www.redmond-reporter.com/news/ceremony-kicks-off-the-opening-of-new-ne-36th-street-bridge/ |work=Redmond Reporter |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170901112649/http://www.redmond-reporter.com/news/ceremony-kicks-off-the-opening-of-new-ne-36th-street-bridge/ |archive-date=September 1, 2017 |df=mdy-all }}{{cite news |last=Oppmann |first=Patrick |date=March 31, 2009 |title=Critics slam Microsoft bridge as waste of stimulus money |url=http://www.cnn.com/2009/US/03/31/bridge.microsoft/ |publisher=CNN |access-date=October 30, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170705005030/http://www.cnn.com/2009/US/03/31/bridge.microsoft/ |archive-date=July 5, 2017 |df=mdy-all }}

Additional projects were funded by the Connecting Washington funding package, which was approved by the state legislature in 2015. An additional ramp is being added to the 148th Avenue Northeast interchange in Overlake, connecting eastbound traffic to the Overlake Village area via a set of new streets and an underpass. It began construction in 2021 and was opened in December 2023 at a cost of $68 million.{{cite news |last=Hatmaker |first=Adrienne |date=May 3, 2022 |title=Tunnel work begins for Overlake access ramp in Redmond |url=https://wsdotblog.blogspot.com/2022/05/tunnel-work-begins-for-overlake-access-ramp-redmond.html |work=WSDOT Blog |publisher=Washington State Department of Transportation |accessdate=May 18, 2022}}{{cite press release |date=December 11, 2023 |title=Access granted: New off-ramp, tunnel linking eastbound SR 520 with Overlake Village in Redmond opens Thursday, Dec. 14 |url=https://wsdot.wa.gov/about/news/2023/access-granted-new-ramp-tunnel-linking-eastbound-sr-520-overlake-village-redmond-opens-thursday-dec |publisher=Washington State Department of Transportation |accessdate=December 14, 2023}} The package also funded $40.9 million to engineer and acquire land for an expanded interchange at 124th Avenue Northeast in Bellevue to serve the Spring District.{{cite web |title=SR 520/124th Avenue NE Interchange Project |url=https://wsdot.wa.gov/construction-planning/search-projects/sr-520124th-avenue-ne-interchange-project |publisher=Washington State Department of Transportation |accessdate=May 18, 2022}}

=Bridge replacement and corridor improvement program=

File:SR 520 Floating Bridge and its replacement from Evergreen Point.jpg

Since the opening of the Evergreen Point Floating Bridge in 1963, several proposals from local governments have requested the construction of a parallel span or additional pontoons to increase capacity and add infrastructure for rapid transit and bicyclists.{{cite news |last=Whitely |first=Peyton |date=November 26, 1972 |title=Reversible lane tops ideas for Evergreen Point bridge |page=A5 |work=The Seattle Times}} Daily traffic crossing the bridge rose from 17,400 cars in 1964 to nearly 100,000 in 1987, making the bridge the worst traffic bottleneck in the state of Washington.{{cite news |last=Gough |first=William |date=August 28, 1988 |title=A bridge too small: At 25 years old, span of Route 520 is beset by chronic congestion |page=A1 |work=The Seattle Times}} By the late 1990s, the bridge was carrying twice as much traffic as it was designed to handle, and calls from Eastside cities and companies for a replacement bridge intensified.{{cite news |last1=Ervin |first1=Keith |last2=Whitely |first2=Peyton |last3=Lopez Williams |first3=Sarah |date=March 16, 1997 |title=Highway 520: Going nowhere fast |page=A1 |url=https://archive.seattletimes.com/archive/19970316/2529058/highway-520-going-nowhere-fast |work=The Seattle Times |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902053655/http://community.seattletimes.nwsource.com/archive/?date=19970316&slug=2529058 |archive-date=September 2, 2017 |df=mdy-all }} WSDOT engineers also determined that sections of the bridge would fail during a large earthquake or a major windstorm, and that the bridge was nearing the end of its life expectancy, necessitating a total replacement.{{cite news |last1=Dudley |first1=Brier |last2=Whitely |first2=Peyton |date=March 4, 1999 |title=Broken-down 520 bridge on last leg? |page=A1 |url=https://archive.seattletimes.com/archive/19990304/2947503/broken-down-520-bridge-on-last-legs----but-no-plans-exist-to-replace-or-upgrade-it |work=The Seattle Times |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902095444/http://community.seattletimes.nwsource.com/archive/?date=19990304&slug=2947503 |archive-date=September 2, 2017 |df=mdy-all }}{{cite news |last=Singer |first=Natalie |date=August 28, 2003 |title=Crossing lake hits crossroads: Issues facing 520 bridge are comparable to '63, when span first opened |page=B1 |work=The Seattle Times}} The bridge underwent a major rehabilitation in 1999, including a seismic retrofit, and increased resistance to stronger sustained winds, to extend its life expectancy to 20 to 25 years.

The Washington State Transportation Commission began seeking alternatives for the bridge replacement project in 1997,{{cite news |last=Whitely |first=Peyton |date=November 22, 1997 |title=Lake Washington traffic study would involve variety of groups |page=A11 |work=The Seattle Times}} including a Sand Point crossing and various designs for a parallel replacement span. The non-bridge elements of the project on the Eastside would be centered on lidding the freeway; a proposal to build a lid over the entire section between Lake Washington and I-405 was rejected due to its projected cost of $2 billion. In 2003, the alternatives were narrowed to a replacement span, with varying lane widths and configurations for interchanges in Seattle.{{cite news |last=Whitely |first=Peyton |date=January 31, 2002 |title=12 options get go-ahead on Highway 520 |page=B1 |work=The Seattle Times}} WSDOT chose the project's preferred alternative, a replacement span with six lanes and a mixed-use trail, in 2011.{{cite web |title=Building the New SR 520 Bridge |url=http://www.520history.org/1956-Present/New520Bridge.htm |publisher=Washington State Department of Transportation |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902092503/http://www.520history.org/1956-Present/New520Bridge.htm |archive-date=September 2, 2017 |df=mdy-all }}{{cite news |last=Thompson |first=Lynn |date=April 29, 2011 |title=Panel approves new 520 bridge – Six-lane highway McGinn is lone dissenter |page=B1 |url=http://old.seattletimes.com/html/localnews/2014902304_520bridge29m.html |work=The Seattle Times |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902095314/http://old.seattletimes.com/html/localnews/2014902304_520bridge29m.html |archive-date=September 2, 2017 |df=mdy-all }} The $5.69 billion megaproject,{{cite news |last=Heller |first=Matthew |date=April 8, 2024 |title=Skanska Lands $1.4B Contract to Revamp Seattle's Portage Bay Bridge |url=https://www.enr.com/articles/58427-skanska-lands-14b-contract-to-revamp-seattles-portage-bay-bridge |work=Engineering News-Record |url-access=limited |accessdate=May 4, 2024}} which encompasses the SR 520 corridor between I-5 and I-405, was funded using a state gas tax and electronic tolls on the floating bridge introduced on December 29, 2011, to repay construction bonds over a 40-year period.{{cite news |last=Lindblom |first=Mike |date=December 27, 2011 |title=520 bridge tolling ready to roll |page=A1 |url=http://old.seattletimes.com/html/localnews/2017100753_tolling27m.html |work=The Seattle Times |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902095115/http://old.seattletimes.com/html/localnews/2017100753_tolling27m.html |archive-date=September 2, 2017 |df=mdy-all }}

Construction of the SR 520 corridor project began in April 2011 on the Eastside, where WSDOT expanded the freeway to six lanes and added HOV lanes. The project, completed in 2014, also included the construction of new bus stations and direct access ramps, new interchanges, park lids covering SR 520, and a multi-use trail.{{cite web |year=2015 |title=SR 520 – Eastside Transit and HOV Project – Complete September 2015 |url=http://www.wsdot.wa.gov/Projects/SR520Bridge/MedinaTo202/ |publisher=Washington State Department of Transportation |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902101800/http://www.wsdot.wa.gov/Projects/SR520Bridge/MedinaTo202/ |archive-date=September 2, 2017 |df=mdy-all }}{{cite news |last=Lindblom |first=Mike |date=June 15, 2014 |title=Evergreen Point transit station opens Monday |page=B2 |url=http://blogs.seattletimes.com/today/2014/06/evergreen-point-transit-station-opens-monday/ |work=The Seattle Times |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902133624/http://blogs.seattletimes.com/today/2014/06/evergreen-point-transit-station-opens-monday/ |archive-date=September 2, 2017 |df=mdy-all }} Construction of the new floating bridge began in 2012, and it was dedicated on April 2, 2016, as the longest floating bridge in the world.{{cite news |last=Bush |first=Evan |date=April 12, 2016 |title=New 520 bridge has traveled long, long road to its opening |page=B7 |url=http://www.seattletimes.com/seattle-news/transportation/new-520-bridge-the-long-long-long-road-to-its-opening/ |work=The Seattle Times |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902095006/http://www.seattletimes.com/seattle-news/transportation/new-520-bridge-the-long-long-long-road-to-its-opening/ |archive-date=September 2, 2017 |df=mdy-all }} The westbound lanes opened on April 11 and the eastbound lanes were opened on April 25.{{cite web |date=April 2017 |title=SR 520 Floating Bridge and Landings Project: Building the World's Longest Floating Bridge |page=6 |url=http://www.wsdot.wa.gov/sites/default/files/2017/05/16/SR520-Booklet-FB042017.pdf |publisher=Washington State Department of Transportation |access-date=October 3, 2018}} The new, {{convert|116|ft|m|adj=mid|-wide}} bridge features four general purpose lanes and two HOV lanes,{{cite news |last=Lindblom |first=Mike |date=April 1, 2016 |title=Party time ahead for new 520 bridge |page=A8 |url=http://www.seattletimes.com/seattle-news/transportation/weekend-party-to-mark-publics-first-chance-to-try-out-new-520-bridge/ |work=The Seattle Times |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902095756/http://www.seattletimes.com/seattle-news/transportation/weekend-party-to-mark-publics-first-chance-to-try-out-new-520-bridge/ |archive-date=September 2, 2017 |df=mdy-all }} as well as a multi-use trail on its north side that opened on December 20, 2017.{{cite news |date=December 20, 2017 |title=WSDOT opens new bike/pedestrian trail on SR 520 bridge |url=http://www.king5.com/article/news/local/wsdot-opens-new-bikepedestrian-trail-on-sr-520-bridge/281-501188946 |publisher=KING 5 News |access-date=December 20, 2017 |url-status=live |archive-url=https://web.archive.org/web/20171221004548/http://www.king5.com/article/news/local/wsdot-opens-new-bikepedestrian-trail-on-sr-520-bridge/281-501188946 |archive-date=December 21, 2017 |df=mdy-all }} Demolition of the former bridge was completed in early 2017.{{cite web |date=May 30, 2017 |title=SR 520 Bridge Replacement and HOV Program: Construction Progress Report, March 2017 |page=4 |url=https://www.wsdot.wa.gov/NR/rdonlyres/DB0B9B6D-7316-4633-9633-0391DA81E725/0/ConstructionReport201703.pdf |publisher=Washington State Department of Transportation |access-date=September 1, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20170902102159/https://www.wsdot.wa.gov/NR/rdonlyres/DB0B9B6D-7316-4633-9633-0391DA81E725/0/ConstructionReport201703.pdf |archive-date=September 2, 2017 |df=mdy-all }} The western approach was partially replaced with a new bridge for westbound traffic in August 2017, with the eastbound lanes temporarily remaining on the old approach bridge. As part of the project, several "ghost ramps" in the Washington Park Arboretum for the cancelled R.H. Thomson Expressway were demolished in 2017, despite calls to preserve them in memory of the protests that cancelled the projects in the 1960s.{{cite news |last=Lindblom |first=Mike |date=January 25, 2013 |title=520 'ramps to nowhere' to come down |page=A1 |url=http://old.seattletimes.com/html/localnews/2020208721_520arboretumxml.html |work=The Seattle Times |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902100409/http://old.seattletimes.com/html/localnews/2020208721_520arboretumxml.html |archive-date=September 2, 2017 |df=mdy-all }}{{cite news |last=Lindblom |first=Mike |date=February 18, 2017 |title=An old Highway 520 crossbeam could be 'urban ruins' honoring anti-freeway activists |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/an-old-highway-520-crossbeam-could-be-urban-ruins-honoring-anti-freeway-activists/ |work=The Seattle Times |access-date=December 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170928202709/https://www.seattletimes.com/seattle-news/transportation/an-old-highway-520-crossbeam-could-be-urban-ruins-honoring-anti-freeway-activists/ |archive-date=September 28, 2017 |df=mdy-all }} A park with one preserved set of columns is planned to be constructed in the 2030s, but remains unfunded by Seattle Parks and Recreation.{{cite news |last=Lindblom |first=Mike |date=June 3, 2024 |title=Seattle's famous 'ramps to nowhere' on the way to becoming a park |url=https://www.seattletimes.com/seattle-news/transportation/seattles-famous-ramps-to-nowhere-on-the-way-to-becoming-a-park/ |work=The Seattle Times |accessdate=June 3, 2024}}

Improvements to the remaining segment of the SR 520 corridor, between I-5 and the floating bridge, were initially left unfunded, but underwent design and environmental review. In 2015, the state legislature approved $1.64 billion in funding for the "Rest of the West" program, which will be constructed between 2018 and 2029.{{cite web |date=June 2016 |title=SR 520 Rest of the West Open House |url=https://www.wsdot.wa.gov/NR/rdonlyres/E6EE0002-A314-422D-8CC9-D1F44A1EE8C8/0/2016_0628_OpenHouseBoards_Sect2_ROTW.pdf |publisher=Washington State Department of Transportation |access-date=September 1, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20170222224145/https://www.wsdot.wa.gov/NR/rdonlyres/E6EE0002-A314-422D-8CC9-D1F44A1EE8C8/0/2016_0628_OpenHouseBoards_Sect2_ROTW.pdf |archive-date=February 22, 2017 |df=mdy-all }}{{cite news |last1=Meredith |first1=Julie |last2=Kyle |first2=Larry |date=May 12, 2016 |title=WSDOT finishing 'The Rest of the West' on SR 520 |url=http://www.djc.com/news/co/12089088.html |work=Seattle Daily Journal of Commerce |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902092058/http://www.djc.com/news/co/12089088.html |archive-date=September 2, 2017 |df=mdy-all }} The first phase of the program, planned to be completed by 2024, included construction of the eastbound lanes of the western approach bridge and a new Montlake Boulevard interchange with HOV lane ramps, a relocated bus station, and a park lid.{{cite news |last=Minnick |first=Benjamin |date=February 13, 2017 |title=WSDOT to seek design-build firm for $425M bridge, lid, trails at Montlake |url=http://www.djc.com/news/ae/12097478.html |work=Seattle Daily Journal of Commerce |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902094943/http://www.djc.com/news/ae/12097478.html |archive-date=September 2, 2017 |df=mdy-all }}{{cite news |last=Lindblom |first=Mike |date=October 11, 2022 |title=Lid project makes progress in Montlake |url=https://www.seattletimes.com/seattle-news/lid-project-makes-progress-in-montlake/ |work=The Seattle Times |accessdate=January 9, 2023}} The eastbound approach to the floating bridge was opened to limited traffic in July 2023 and expanded to carry three lanes in its permanent configuration the following month.{{cite news |last=Peer |first=Steve |date=July 24, 2023 |title=New day, new way in Seattle's Montlake neighborhood |url=https://wsdotblog.blogspot.com/2023/07/new-day-new-way-montlake.html |work=WSDOT Blog |publisher=Washington State Department of Transportation |accessdate=July 31, 2023}} The HOV access ramps to Montlake Boulevard were opened in September 2024.{{cite news |last=Smith |first=Helen |date=September 16, 2024 |title=How new HOV ramps between SR 520 and Montlake are expected to help traffic |url=https://www.king5.com/article/news/local/seattle/new-hov-lanes-open-sr-520-westbound-montlake-neighborhood/281-922c004d-9a48-41e2-a8b0-a7d7eb6a19b5 |publisher=KING 5 News |accessdate=September 18, 2024}}

The second phase, to be constructed between 2020 and 2031, will include a new bridge across Portage Bay, a park lid near Roanoke Park, and a new HOV lane ramp to the I-5 reversible express lanes.{{cite book |date=June 2011 |title=SR 520, I-5 to Medina: Bridge Replacement and HOV Project Section 106 Technical Report |type=Report |chapter=Executive Summary and Introduction |pages=viii–x |chapter-url=http://www.wsdot.wa.gov/NR/rdonlyres/0A44B067-9EF3-4783-9FCD-83C1B2AE857C/0/SR520_Section106_TechnicalReport_SummaryIntroduction.pdf |publisher=Washington State Department of Transportation |access-date=September 1, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20170902102458/http://www.wsdot.wa.gov/NR/rdonlyres/0A44B067-9EF3-4783-9FCD-83C1B2AE857C/0/SR520_Section106_TechnicalReport_SummaryIntroduction.pdf |archive-date=September 2, 2017}}{{cite news |last=Lindblom |first=Mike |date=September 26, 2018 |title=I-5 will add a 5th express lane to serve future Eastside-South Lake Union bus routes |url=https://www.seattletimes.com/seattle-news/transportation/i-5-will-add-a-5th-express-lane-to-serve-future-eastside-south-lake-union-bus-routes/ |work=The Seattle Times |access-date=September 26, 2018}} The express lane ramp, planned to cost $68 million, was expected open in early 2024, but it was later delayed to 2030 due to the inability to increase transit service on the corridor.{{cite news |last=Lindblom |first=Mike |date=November 16, 2022 |title=A crumbling Highway 520 ramp support needs a do-over |url=https://www.seattletimes.com/seattle-news/transportation/a-crumbling-highway-520-ramp-support-needs-a-do-over/ |work=The Seattle Times |accessdate=November 17, 2022}}{{cite news |last=Lindblom |first=Mike |date=July 31, 2023 |title=WSDOT drops plan for a 2024 Highway 520/I-5 bus ramp. What does that mean for you? |url=https://www.seattletimes.com/seattle-news/transportation/wsdot-drops-plan-for-a-2024-highway-520-i-5-bus-ramp-what-does-that-mean-for-you/ |work=The Seattle Times |accessdate=July 31, 2023}} The Portage Bay bridge and Roanoke lid are expected to begin construction in late 2024 and be finished in 2031, in tandem with the express lane ramp, at a cost of up to $1.4 billion.{{cite news |date=April 4, 2024 |title=Skanska inks $1.4B contract for new Portage Bay Bridge |url=https://www.djc.com/news/co/12163106.html |work=Seattle Daily Journal of Commerce |url-access=subscription |accessdate=May 4, 2024}} The third phase is a planned second bascule bridge over the Montlake Cut that parallels the existing Montlake Bridge to increase vehicular capacity.{{cite web |date=May 31, 2017 |title=Questions and Answers: Next Phase of SR 520 construction in Seattle |page=3 |url=https://www.wsdot.wa.gov/NR/rdonlyres/03BCD36A-56DA-4649-99CA-B090521C56E1/0/2017_0531_SR520_ROTW_FAQs_Final.pdf |publisher=Washington State Department of Transportation |access-date=September 1, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20170902041444/https://www.wsdot.wa.gov/NR/rdonlyres/03BCD36A-56DA-4649-99CA-B090521C56E1/0/2017_0531_SR520_ROTW_FAQs_Final.pdf |archive-date=September 2, 2017 |df=mdy-all }}

Mass transit

The SR 520 corridor is served by Sound Transit Express Route 545,{{cite news |last=Pryne |first=Eric |date=November 5, 2004 |title=Commuters settle bus-reroute dispute |page=B4 |url=http://old.seattletimes.com/html/eastsidenews/2002082737_busroute05m.html |work=The Seattle Times |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170901120118/http://old.seattletimes.com/html/eastsidenews/2002082737_busroute05m.html |archive-date=September 1, 2017 |df=mdy-all }} as well as other Sound Transit Express, King County Metro, and Community Transit bus routes.{{cite map |date=September 2016 |title=Metro Transit System: Northeast Area |url=http://metro.kingcounty.gov/maps/system/2016/sept/metro-system-map-northeast.pdf |publisher=King County Metro |access-date=August 31, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20170204113932/http://metro.kingcounty.gov/maps/system/2016/sept/metro-system-map-northeast.pdf |archive-date=February 4, 2017 |df=mdy-all }} The corridor averaged about 24,500 weekday riders in 2016,{{cite web |date=May 4, 2017 |title=SR-520 Project: Initial Findings from Data Analysis |url=http://www.kingcounty.gov/depts/transportation/metro/programs-projects/link-connections/~/media/depts/transportation/metro/programs-projects/link-connections/sr-520/sr520-sounding-board-presentation-20170504-initial-findings.ashx |publisher=King County Metro |access-date=January 7, 2018 |url-status=live |archive-url=https://web.archive.org/web/20180108014850/http://www.kingcounty.gov/depts/transportation/metro/programs-projects/link-connections/~/media/depts/transportation/metro/programs-projects/link-connections/sr-520/sr520-sounding-board-presentation-20170504-initial-findings.ashx |archive-date=January 8, 2018 |df=mdy-all }} using 700 bus trips on 18 routes.{{cite web |title=Bus Service Bridging Lake Washington |url=http://metro.kingcounty.gov/tops/get-you-there/520-tolling/bridging.html |publisher=King County Metro |access-date=January 7, 2018 |url-status=live |archive-url=https://web.archive.org/web/20180108014211/http://metro.kingcounty.gov/tops/get-you-there/520-tolling/bridging.html |archive-date=January 8, 2018 |df=mdy-all }} During peak periods, buses travel on SR 520 every one to four minutes between the Evergreen Point Floating Bridge and I-405.{{cite book |date=December 2009 |title=SR 520, Medina to SR 202: Eastside Transit and HOV Project Environmental Assessment, Appendix Q: Transportation Discipline Report |chapter=Chapter 8: Transit |type=Report |page=8{{hyphen}}3 |chapter-url=https://www.wsdot.wa.gov/NR/rdonlyres/F148A1F4-EE66-47AB-841D-C79611C41F26/0/AppxQ_Transp_Ch8.pdf |publisher=Washington State Department of Transportation |access-date=August 31, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170210041953/https://www.wsdot.wa.gov/NR/rdonlyres/F148A1F4-EE66-47AB-841D-C79611C41F26/0/AppxQ_Transp_Ch8.pdf |archive-date=February 10, 2017 |df=mdy-all }}

Sound Transit began Link light rail service along the Redmond portion of the SR 520 corridor in April 2024, with the opening of the 2 Line to Redmond Technology station.{{cite news |last=Belman |first=Brooke |date=August 24, 2023 |title=Get ready for new Link service on the Eastside next spring |url=https://www.soundtransit.org/blog/platform/get-ready-new-link-service-eastside-next-spring |work=The Platform |publisher=Sound Transit |accessdate=August 30, 2023}}{{cite news |last1=Lindblom |first1=Mike |last2=Kroman |first2=David |date=April 27, 2024 |title=Eastside light rail line opens as huge crowds try out the ride |url=https://www.seattletimes.com/seattle-news/transportation/eastside-light-rail-line-opens-as-huge-crowds-try-out-the-ride/ |work=The Seattle Times |accessdate=April 27, 2024}} Approved by voters in 2008, the line will connect Redmond Technology station at Northeast 40th Street and Overlake Village station at 152nd Avenue Northeast to Seattle and Downtown Bellevue, crossing Lake Washington on the I-90 floating bridge.{{cite news |last=Lindblom |first=Mike |date=May 14, 2017 |title=World's first light rail on a floating bridge: For I-90, Sound Transit had to invent 'a brilliant solution' |page=A12 |url=http://www.seattletimes.com/seattle-news/transportation/light-rail-track-floating-bridge-i-90-sound-transit/ |work=The Seattle Times |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902142331/http://www.seattletimes.com/seattle-news/transportation/light-rail-track-floating-bridge-i-90-sound-transit/ |archive-date=September 2, 2017 |df=mdy-all }}{{cite web |date=October 2016 |title=East Link Extension Fact Sheet |url=https://www.soundtransit.org/sites/default/files/project-documents/201610-east-link-extension-project-overview-folio-final.pdf |publisher=Sound Transit |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170902134820/https://www.soundtransit.org/sites/default/files/project-documents/201610-east-link-extension-project-overview-folio-final.pdf |archive-date=September 2, 2017 |df=mdy-all }} The line is scheduled to be extended along SR 520 to Downtown Redmond in 2025, using funding from the Sound Transit 3 program approved by voters in 2016.{{cite web |date=May 2017 |title=Downtown Redmond Link Extension Fact Sheet |url=https://www.soundtransit.org/sites/default/files/project-documents/downtown-redmond-link-extension-fact-sheet.pdf |publisher=Sound Transit |access-date=September 1, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170630053219/https://www.soundtransit.org/sites/default/files/project-documents/downtown-redmond-link-extension-fact-sheet.pdf |archive-date=June 30, 2017 |df=mdy-all }} The rebuilt floating bridge was also designed to accommodate a future light rail extension, requiring supplemental pontoons and new approaches.{{cite web |title=SR 520: Light Rail in the Corridor |url=https://www.wsdot.wa.gov/Projects/SR520Bridge/About/LightRail.htm |publisher=Washington State Department of Transportation |access-date=October 29, 2017 |url-status=live |archive-url=https://web.archive.org/web/20160720233621/http://www.wsdot.wa.gov/Projects/SR520Bridge/About/LightRail.htm |archive-date=July 20, 2016 |df=mdy-all }}

Exit list

{{WAint

|location=Seattle

|lspan=4

|mile=0.00

|road={{jct|state=WA|I|5|location1=Portland|location2=Vancouver BC

}}

|notes=Western terminus

}}

{{WAint

|mile=0.20

|type=incomplete

|road=Roanoke Street / Harvard Avenue

|notes=Westbound exit only

}}

{{WAint

|mile=0.94

|road={{jctname|state=WA|SR|513|noshield1=no|name1=Montlake Boulevard|location1=University of Washington}}

|notes=Last eastbound exit before toll

}}

{{WAint

|mile=1.63

|type=incomplete

|road=Lake Washington Boulevard

|notes=Eastbound entrance only

}}

{{jctbridge|state=WA

|location_special=Lake Washington

|mile=1.63

|mile2=3.98

|type=etc

|bridge=Evergreen Point Floating Bridge

}}

{{WAint

|location=Medina

|mile=4.14

|type=HOV

|road=Evergreen Point Freeway Station

|notes=Bus only

}}

{{WAint

|location=Hunts Point

|mile=4.57

|type=incomplete

|road=84th Avenue Northeast

|notes=Eastbound exit and westbound entrance

}}

{{WAint

|location=Clyde Hill

|lspan=2

|mile=5.39

|type=incomplete

|road=92nd Avenue Northeast

|notes=Westbound exit and eastbound entrance; last westbound exit before toll

}}

{{WAint

|mile=5.15

|type=HOV

|road=Yarrow Point Freeway Station

|notes=Bus only

}}

{{WAint

|location=Bellevue

|lspan=5

|mile=5.97

|type=incomplete

|road=Lake Washington Boulevard Northeast / Bellevue Way

|notes=Eastbound exit and westbound entrance; former SR 908

}}

{{WAint

|mile=6.29

|type=incomplete

|road=108th Avenue Northeast

|notes=No eastbound exit (except HOV)

}}

{{WAint

|mile=6.94

|road={{jct|state=WA|I|405|city1=Renton|city2=Everett}}

}}

{{WAint

|mile=7.50

|type=incomplete

|road=124th Avenue Northeast

|notes=Eastbound exit and westbound entrance

}}

{{WAint

|mile=9.17

|road=148th Avenue Northeast / 152nd Avenue Northeast

|notes=Access to 152nd Avenue Northeast only through eastbound offramp

|type=incomplete}}

{{WAint

|location=Redmond

|lspan=3

|mile=9.71

|mile2=11.21

|road=Northeast 40th Street / Northeast 51st Street

}}

{{WAint

|mile=11.79

|road=West Lake Sammamish Parkway Northeast

|notes=Former SR 901

}}

{{WAint

|mile=12.82

|road={{jct|state=WA|SR|202|name1=Redmond Way}}

|notes=Westbound exit and eastbound entrance via Northeast 76th Street; continues as Avondale Road

}}

References

External links

{{commons category-inline}}
[https://www.angelfire.com/wa2/hwysofwastate/sr520.html Highways of Washington State: SR 520]
[https://wsdot.wa.gov/construction-planning/major-projects/sr-520-bridge-replacement-and-hov-program SR 520 Bridge Replacement and HOV Program]

Category:Transportation in King County, Washington

Category:Transportation in Seattle

520

Category:Seattle metropolitan area

Category:Freeways in the United States

Category:Redmond, Washington

Category:Bellevue, Washington