Washington State Route 99

SR 99 follows a section of former U.S. Route 99 (US 99) within the Seattle metropolitan area, from Fife to southern Everett.{{cite news |last=Muhlstein |first=Julie |date=May 21, 2016 |title=Highway 99 renamed in honor of Snohomish settler William P. Stewart |url=https://www.heraldnet.com/news/highway-99-renamed-in-honor-of-snohomish-settler-william-p-stewart/ |work=The Everett Herald |access-date=September 18, 2018}} It is officially designated as the William P. Stewart Memorial Highway, but is commonly known as the Pacific Highway or by one of its local names. The entire highway is listed as part of the National Highway System, a national network of roads identified as important to the national economy, defense, and mobility.{{cite web |year=2017 |title=State Highway National Highway System Routes in Washington |url=https://www.wsdot.wa.gov/mapsdata/travel/hpms/pdf/washington-2017-state-highway-nhs-list.pdf |publisher=Washington State Department of Transportation |access-date=September 18, 2018}}{{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=September 18, 2018}} A section of the highway from Tukwila to Shoreline is also designated as a Highway of Statewide Significance by the state legislature.{{cite web |date=July 26, 2009 |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 |access-date=September 18, 2018 |archive-date=July 24, 2013 |archive-url=https://web.archive.org/web/20130724190950/http://www.wsdot.wa.gov/NR/rdonlyres/50EC9EB9-DB3D-4823-B5D2-5348409FB8CE/0/HSSlist2009mod2.pdf |url-status=dead }} The Washington State Department of Transportation (WSDOT) estimates that average traffic volumes on SR 99, measured in terms of annual average daily traffic for 2016, range from a minimum of 17,000 vehicles on Everett Mall Way to a maximum of 97,000 at the First Avenue South Bridge in Seattle.{{cite report |year=2017 |title=2016 Annual Traffic Report |pages=126–128 |url=https://www.wsdot.wa.gov/mapsdata/travel/pdf/Annual_Traffic_Report_2016.pdf |publisher=Washington State Department of Transportation |url-status=dead |archive-url=https://web.archive.org/web/20200208001700/https://www.wsdot.wa.gov/mapsdata/travel/pdf/Annual_Traffic_Report_2016.pdf |archive-date=February 8, 2020 |access-date=September 18, 2018}}

File:SeaTac Airport Station, from International Boulevard.jpg serving Seattle–Tacoma International Airport, seen from across SR 99|alt=Elevated train station seen above a freeway on an embankment. A bus stop can be seen below the embankment and across a road from a sign reading "SeaTac/Airport Station" in the foreground.]]

SR 99 begins in Fife as an extension of 54th Avenue East at a partial cloverleaf interchange with Interstate 5. Immediately north of the interchange, SR 99 turns east onto Pacific Highway and passes the Emerald Queen Casino, a gambling and hotel facility operated by the Puyallup Tribe, and a commercial district at the outskirts of Fife. The highway makes a gradual turn to the north, parallel to Interstate 5 and the West Fork of Hylebos Creek, and enters Milton. SR 99 travels north along a ridge and crosses into King County, turning northeast and entering the city of Federal Way. The road cuts through a forested part of the Hylebos basin near West Hylebos Wetlands Park and reaches a commercial district surrounding Kitts Corner.{{cite news |last=McDonalds |first=Cathy |date=December 24, 2009 |title=History and a rare peat bog at West Hylebos Wetlands Park |page=D6 |url=http://old.seattletimes.com/html/outdoors/2010581210_nwwwalkabout24.html |work=The Seattle Times |url-status=dead |archive-url=https://web.archive.org/web/20180919061821/http://old.seattletimes.com/html/outdoors/2010581210_nwwwalkabout24.html |archive-date=September 19, 2018 |access-date=September 18, 2018}}{{google maps |title=State Route 99 (southern segment) |url=https://www.google.com/maps/dir/47.2408359,-122.3570482/47.4636616,-122.2896382/@47.3512193,-122.4541224,11z/am=t/data=!3m1!4b1!4m4!4m3!2m1!1b1!3e0 |access-date=September 25, 2017}}

At Kitts Corner, the highway intersects the western section of State Route 18, which continues east to an interchange with I-5 and onto a freeway traveling towards Auburn and Covington.{{cite WSDOT map |year=2014 |inset=[https://web.archive.org/web/20211030072139/https://wsdot.wa.gov/sites/default/files/2017/08/31/highway-map-PugetSound_Full.pdf Puget Sound] |access-date=September 25, 2017}} SR 99 continues due north through Federal Way's main commercial strip and passing Celebration Park, The Commons at Federal Way, and Steel Lake. The highway gains a set of high-occupancy vehicle lanes that are also open to right turns into parking lots and side streets.{{cite news |last=Allmain |first=Greg |date=April 14, 2012 |title=Federal Way celebrates Pacific Highway project |url=http://www.federalwaymirror.com/news/federal-way-celebrates-pacific-highway-project/ |work=Federal Way Mirror |access-date=December 18, 2018}} From northern Federal Way to the Redondo area of Des Moines, SR 99 is concurrent with SR 509, which continues southwest to Dash Point State Park and northwest to downtown Des Moines, for {{convert|4|mi|km|0|spell=in}}.

The two highways pass Saltwater State Park and the former Midway landfill before splitting near Highline College at an intersection with Kent Des Moines Road (SR 516). SR 99 then enters the city of SeaTac and continues north as International Boulevard, passing a federal detention center and light rail station on the southwest side of Angle Lake. The highway runs along the east side of Seattle–Tacoma International Airport and its expressway, serving the airport's terminals, parking garage, light rail station, and nearby hotels. SR 99 terminates at an interchange with SR 518 in southern Tukwila, near the airport's consolidated rental car facility and the Tukwila light rail station. A {{convert|2.4|mi|km|adj=mid}} section of International Boulevard in Tukwila forms the gap between the two segments of SR 99.{{cite web |date=March 1, 2004 |title=House Bill Report: SB 5376 |url=https://lawfilesext.leg.wa.gov/biennium/2003-04/Pdf/Bill%20Reports/House%20Historical/5376%20BRH%20TR.pdf |publisher=Washington State Legislature |access-date=September 18, 2018}}

File:Qwest Field with a blue roof.jpg on the Alaskan Way Viaduct, which until 2019 carried SR 99 through Downtown Seattle|alt=An elevated highway with inbound traffic seen atop a double-decked structure. Several buildings can be seen off to the side of the highway, while CenturyLink Field and Mount Rainier can be seen in the background.]]{{anchor|Northern segment}}

SR 99 resumes at the north end of Tukwila International Boulevard and supersedes SR 599, a short freeway connecting to I-5, near the Duwamish River. The freeway travels northwest along the river's west bank through an industrial area that faces Boeing Field. It then enters the city of Seattle and intersects the Des Moines Memorial Drive in the South Park neighborhood before the freeway ends. At an interchange with SR 509, SR 99 turns north and travels across the Duwamish River on the First Avenue South Bridge, a pair of bascule bridges that form a continuation of the SR 509 freeway.{{google maps |title=State Route 99 (northern segment) |url=https://www.google.com/maps/dir/47.498471,-122.2951948/47.9151124,-122.208222/@47.7067229,-122.557763,10z/am=t/data=!3m1!4b1!4m26!4m25!1m20!3m4!1m2!1d-122.3223128!2d47.5244958!3s0x5490422be2f38227:0x8f2b79cd85ce7ae5!3m4!1m2!1d-122.333833!2d47.5447626!3s0x54904196545a2bbb:0x4f737bfcfb30e133!3m4!1m2!1d-122.3393542!2d47.575815!3s0x54904031d80f4741:0xd05c12bf991c3398!3m4!1m2!1d-122.3437142!2d47.6233561!3s0x549015478f0b5761:0xe4ca9be803852580!1m0!2m1!1b1!3e0 |link=no |access-date=February 4, 2019}}{{cite news |last=Beers |first=Carole |date=February 2, 1997 |title=New Duwamish span opens while old one is fixed |page=B1 |work=The Seattle Times}}

At the north end of the bridge, SR 99 turns northwest onto East Marginal Way South and travels through Seattle's industrial neighborhood along the east bank of the Duwamish Waterway. The six-lane street turns north and passes a cement factory before transforming into a four-lane freeway at an interchange with the West Seattle Freeway on the east end of the West Seattle Bridge. SR 99 widens to six lanes, including a northbound bus lane, and passes through the SoDo neighborhood as the dividing line between the Port of Seattle's container ship terminals to the west and industrial businesses to the east beyond a rail terminal. The freeway passes the corporate headquarters of Starbucks and Coast Guard Station Seattle before turning northeast to reach the southern portal of the Alaskan Way Tunnel near Lumen Field and T-Mobile Park. The tunnel portal includes ramps to and from nearby streets, including Dearborn Street, Alaskan Way, and a frontage road along the east side of the highway.{{cite web |date=January 2017 |title=Traveling on the new SR 99 corridor |url=https://www.wsdot.wa.gov/Projects/Viaduct/Media/Default/-NewDocuments/Library/2017_0106_FutureAccess.pdf |publisher=Washington State Department of Transportation |url-status=dead |archive-url=https://web.archive.org/web/20201112022647/https://www.wsdot.wa.gov/Projects/Viaduct/Media/Default/-NewDocuments/Library/2017_0106_FutureAccess.pdf |archive-date=November 12, 2020 |access-date=February 4, 2019}}

The tunnel travels {{convert|1.8|mi|km}} under Downtown Seattle and carries SR 99 along the central waterfront, running roughly parallel to the former Alaskan Way Viaduct. It is arranged with two stacked decks, carrying two lanes of southbound traffic on the upper deck and two lanes of northbound traffic on the lower deck.{{cite news |last=Lindblom |first=Mike |date=November 19, 2018 |title=When does the viaduct close? How much is the tunnel toll? Your guide to Seattle's Highway 99 project |url=https://www.seattletimes.com/seattle-news/transportation/we-answer-your-questions-about-the-viaducts-closure-in-january-and-the-highway-99-tunnel-opening/ |work=The Seattle Times |access-date=December 23, 2018}} SR 99 emerges from the tunnel on the north side of Denny Way and travels onto Aurora Avenue North through the South Lake Union neighborhood, located to the east of the Seattle Center and the Space Needle.{{cite news |last1=Lindblom |first1=Mike |last2=Baruchman |first2=Michelle |date=January 31, 2019 |title=Highway 99 tunnel opens next week. Here are answers to your questions about the project |url=https://www.seattletimes.com/seattle-news/transportation/the-highway-99-tunnel-opens-next-week-here-are-answers-to-your-questions-about-the-project/ |work=The Seattle Times |access-date=January 31, 2019}} Aurora Avenue continues north as a six-lane street with bus lanes and a median barrier that restricts access from side streets to right-in/right-out. The highway runs along the eastern slope of Queen Anne Hill, above the Westlake neighborhood along Lake Union, to the Lake Washington Ship Canal.

File:Aurora Avenue and Bridge Deck 20.jpg and the Downtown Seattle skyline in the background|alt=A divided highway seen alongside several buildings, with a city skyline in the background behind a hill.]]

Aurora Avenue then crosses the ship canal on the George Washington Memorial Bridge (commonly known as the Aurora Bridge), a steel cantilever arch bridge with a clearance of {{convert|167|ft|m}}.{{cite news |last=Beason |first=Tyrone |date=November 25, 2015 |title=Seattle's gritty bridges are built for function, not beauty |url=https://www.seattletimes.com/pacific-nw-magazine/seattles-gritty-bridges-are-built-for-function-not-beauty/ |work=The Seattle Times |access-date=September 18, 2018}} The bridge has six lanes and no median barrier, which resumes after an interchange with Bridge Way on the north approach, which crosses over the Fremont Troll.{{cite news |last=Lindblom |first=Mike |date=June 19, 2018 |title=Can a 'zipper' eliminate the squeeze? |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/would-the-golden-gates-road-zipper-make-seattles-aurora-bridge-safer/ |work=The Seattle Times |access-date=December 21, 2018}} The highway continues north through part of Fremont and intersects North 46th Street before entering Woodland Park. SR 99 forms the boundary between Woodland Park to the east and the Woodland Park Zoo to the west and passes under a series of three pedestrian overpasses.{{cite news |last=Dorpat |first=Paul |author-link=Paul Dorpat |date=December 26, 2008 |title=Pedestrian overpass on Seattle's busy Aurora Avenue saves lives |url=http://old.seattletimes.com/html/pacificnw/2008562061_pacificpdorp28.html |work=The Seattle Times |url-status=dead |archive-url=https://web.archive.org/web/20180919094435/http://old.seattletimes.com/html/pacificnw/2008562061_pacificpdorp28.html |archive-date=September 19, 2018 |access-date=September 18, 2018}} The highway turns northeast to follow the shore of Green Lake and passes through the residential districts of Phinney Ridge and Greenwood, where traffic signals replace the medians and right-in/right-out access. SR 99 passes west of the North Seattle College campus in Licton Springs and intersects Northgate Way, a major street that provides access to Northgate Mall. Aurora Avenue then bisects the Evergreen Washelli Memorial Park, the city's largest cemetery,{{cite news |last=Broom |first=Jack |date=May 25, 1986 |title=The land of the hereafter: A cemetery has a life of its own |page=12 |work=The Seattle Times}} and passes between Haller Lake and Bitter Lake before reaching the northern city boundary at North 145th Street (SR 523).

SR 99 enters Shoreline and passes through the city's main commercial district, running parallel to the Interurban Trail.{{cite news |last=Bock |first=Paula |date=December 9, 2007 |title=On the edge of opportunity: A community stretches for the buzz |page=12 |work=The Seattle Times |url=http://old.seattletimes.com/html/pacificnw12092007/2004049901_pacificpthere09.html |url-status=dead |archive-url=https://web.archive.org/web/20180919132339/http://old.seattletimes.com/html/pacificnw12092007/2004049901_pacificpthere09.html |archive-date=September 19, 2018 |access-date=September 18, 2018}} The stretch of Aurora Avenue through Shoreline has a landscaped median, plant buffers for sidewalks, several left-turn pockets, and an overpass for the Interurban Trail.{{cite news |last=Salyer |first=Sharon |date=August 28, 2017 |title=Edmonds has big plans for its Highway 99 improvements |url=https://www.heraldnet.com/news/edmonds-has-big-plans-for-its-highway-99-improvements/ |work=The Everett Herald |access-date=September 18, 2018}} Near Shorewood High School and the Shoreline city hall, the highway is flanked to the east by the Interurban Trail and a park with a preserved section of the original North Trunk Road, which was paved in red bricks.{{cite news |last=Smith |first=Evan |date=April 14, 2009 |title=A compromise for the 'Red Brick Road' |url=https://www.heraldnet.com/uncategorized/a-compromise-for-the-red-brick-road/ |work=The Everett Herald |access-date=September 18, 2018}} After passing Echo Lake and the Aurora Village shopping center, SR 99 reaches an interchange with SR 104 near the boundary between King and Snohomish counties. The highway intersects SR 104 Spur on the county line itself, which lies south of the interchange.

File:Everett Mall Way (SR 99) northbound at 4th Avenue, Everett.jpg

After the interchange, the highway turns northeast and runs through a predominantly commercial area of Edmonds, passing east of the Swedish Medical Center's Edmonds campus and west of Hall Creek and the Interurban Trail. SR 99 continues northeast into Lynnwood and passes the Edmonds College campus before reaching the Crossroads commercial district at a junction with 196th Street Southwest (SR 524).{{cite news |last=Watkins |first=Amy |date=October 29, 2013 |title=New shopping center opens in Lynnwood |url=https://www.heraldnet.com/uncategorized/new-shopping-center-opens-in-lynnwood/ |work=The Everett Herald |access-date=September 18, 2018}} The highway runs along the city's retail strip and through its international district (also described as a Koreatown),{{cite news |last=Kugiya |first=Hugo |date=May 5, 2011 |title=Bibimbap's on the map in Koreatown North |url=https://crosscut.com/2011/05/bibimbaps-on-map-in-koreatown-north |work=Crosscut.com |access-date=September 18, 2018}} which is surrounded by apartments and homes that are set back from SR 99.

Beyond the city limits of Lynnwood, SR 99 enters an unincorporated area near Lake Serene. The highway intersects SR 525 at a partial cloverleaf interchange and crosses Airport Road, which provides access to Paine Field and its passenger terminal. The highway travels north into Everett on Evergreen Way and turns northeast onto Everett Mall Way in the Fairmont neighborhood. SR 99 then passes through several residential subdivisions and reaches the Everett Mall, where it turns north and terminates at the Broadway Interchange. The interchange includes connections to I-5, the Boeing Freeway (SR 526), and SR 527. The road itself continues north towards Downtown Everett as Broadway.

SR 99 was created from the remnants of US 99, a national highway which spanned Western Washington from the Oregon border in Vancouver to the Canadian border at the Peace Arch in Blaine. US 99 itself was preceded by a century-old network of military roads, wagon roads, and auto trails that were built across the state in the 19th century and early 20th century until it was formally incorporated into the state highway system.{{cite book |last=Flood |first=Chuck |year=2013 |title=Washington's Highway 99 |page=8 |publisher=Arcadia Publishing |location=Charleston, South Carolina |isbn=978-0-7385-9618-1 |oclc=811603138 |url=https://books.google.com/books?id=GP6xAQ4a9RUC |via=Google Books |access-date=October 6, 2018}}

In southern King County, modern-day SR 99 runs parallel to a section of the Fort Steilacoom–Fort Bellingham military road, constructed in the 1850s by the U.S. Army.{{cite news |last=Meador |first=Karen |date=November 13, 2017 |title=Military Road: South King County's link to the Civil War |url=http://www.federalwaymirror.com/life/military-road-south-king-countys-link-to-the-civil-war/ |work=Federal Way Mirror |access-date=October 7, 2018}}{{cite news |last=Matassa Flores |first=Michele |date=March 8, 1989 |title=Federal Way leaves rural past behind |page=H4 |work=The Seattle Times}} A section north of Seattle follows the R.F. Morrow wagon road, constructed in 1901 and later incorporated into the North Trunk Road.{{cite web |date=March 2003 |title=State Route 99 North/Aurora Avenue North Route Development Plan |page=1 |url=http://www.wsdot.wa.gov/NR/rdonlyres/C1DC4A4E-3C3E-4A6F-88CF-D40DDB6E1CD4/0/introduction.pdf |publisher=Washington State Department of Transportation |url-status=dead |archive-url=https://web.archive.org/web/20180123072812/http://www.wsdot.wa.gov/NR/rdonlyres/C1DC4A4E-3C3E-4A6F-88CF-D40DDB6E1CD4/0/introduction.pdf |archive-date=January 23, 2018 |access-date=October 7, 2018}} The North Trunk Road was completed from Seattle to the area east of Edmonds in August 1912 and initially paved with bricks.{{cite news |date=October 1, 2013 |title=This Month in Edmonds History: North Trunk Road |url=https://myedmondsnews.com/2013/10/month-edmonds-history-north-trunk-road/ |work=My Edmonds News |access-date=September 19, 2018}} The Seattle–Everett Interurban Railway was also built along sections of the wagon road in 1906 and would serve Everett–Seattle traffic until 1939.{{cite web |last=Crowley |first=Walt |date=September 19, 2000 |title=Interurban rail service between Everett and Seattle ends February 20, 1939. |url=https://www.historylink.org/File/2669 |work=HistoryLink |access-date=October 4, 2018}}

The Pacific Highway, an inter-state coastal highway, was championed by good roads advocates in the early 1910s and added to the state highway system in 1913.{{cite news |date=September 20, 1910 |title=Autoists Organize Highway Association |page=9 |work=The Seattle Times}}{{cite book |date=March 12, 1913 |title=Session Laws of the State of Washington, 1913 |chapter=Chapter 65: Classifying Public Highways |page=221 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1913c65.pdf |publisher=Washington State Legislature |access-date=October 4, 2018}} It originally followed the Puyallup and Green rivers from Tacoma to Renton and the Bothell–Everett Highway (now SR 527) along North Creek in Snohomish County.{{cite map |title=Map of Washington State Highways Authorized by Legislative Acts of 1913, with 1915 changes |scale=1 inch = 18 miles |publisher=Washington State Highway Commission |url=https://content.libraries.wsu.edu/digital/collection/maps/id/755 |via=Washington State University Libraries Digital Collection |access-date=October 7, 2018}} The highway was designated as State Road 1 in 1923,{{cite book |date=March 19, 1923 |title=Session Laws of the State of Washington, 1923 |chapter=Chapter 185: Primary and Secondary State Highways |pages=627–628 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1923c185.pdf |publisher=Washington State Legislature |access-date=October 7, 2018}} a number that it would retain after the creation of Primary State Highway 1 (PSH 1) in 1937.{{cite book |date=March 17, 1937 |title=Session Laws of the State of Washington, Twenty-Fifth Session |chapter=Chapter 190: Establishment of Primary State Highways |pages=933–943 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1937c190.pdf |publisher=Washington State Legislature |access-date=October 8, 2018}} The Pacific Highway was incorporated into the new national numbered highway system in 1926 as US 99, connecting the three West Coast states and running from the Mexican border to Canada.{{cite map |author1= Bureau of Public Roads |author2= American Association of State Highway Officials |date= November 11, 1926 |title= United States System of Highways Adopted for Uniform Marking by the American Association of State Highway Officials |url= https://commons.wikimedia.org/wiki/File:United_States_System_of_Highways_Adopted_for_Uniform_Marking_by_the_American_Association_of_State_Highway_Officials.jpg |scale= 1:7,000,000 |location= Washington, DC |publisher= United States Geological Survey |oclc= 32889555 |access-date= November 7, 2013 |via= Wikimedia Commons |name-list-style= amp}} The Bothell route was bypassed by a newer and straighter highway to the west that opened on October 9, 1927,{{cite book |last=Cloud |first=Ray V. |year=1953 |title=Edmonds, the Gem of Puget Sound |page=96 |publisher=Edmonds Tribune-Review Press |oclc=26225475}} shortening the distance from Seattle to Everett by {{convert|3.8|mi|km}} and featuring overpasses for the existing interurban and a gravel median strip in some sections.{{cite news |date=August 31, 1927 |title=Everett-Seattle Highway Project Open October 15 |pages=[https://www.newspapers.com/article/the-everett-daily-herald-everett-seattle/139723882/ 1], [https://www.newspapers.com/article/the-everett-daily-herald-everett-seattle/139723890/ 3] |work=The Everett Herald |url=https://www.newspapers.com/article/the-everett-daily-herald-everett-seattle/139723882/ |via=Newspapers.com |accessdate=January 27, 2024}} It was built by the state government in tandem with a set of new bridges connecting Everett to Marysville and cost $645,000 (equivalent to ${{Format price|{{Inflation|US-GDP|645000|1927}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} to construct and partially pave.{{cite news |date=August 29, 1927 |title=New Highway Shortens Trip; Everett Road Open Oct. 15 |page=20 |work=The Seattle Times}} The White River route was bypassed in early 1928 by the {{convert|24|mi|km|adj=mid|-long}} Highline route, which traveled along the western plateau near Des Moines.{{cite map |year=1927 |map=Washington |title=Rand McNally Junior Auto Road Atlas |pages=82–83 |publisher=Rand McNally |scale=1:1,500,000 |oclc=921180471 |url=https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~33772~1171488 |via=David Rumsey Historical Map Collection |access-date=October 7, 2018}}{{cite news |last=Foster |first=George |date=March 19, 1992 |title=The long history of a highway built for life's fast lane |page=A14 |work=Seattle Post-Intelligencer}} The new highway cost $3 million (equivalent to ${{Format price|{{Inflation|US-GDP|3000000|1928}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} to construct and pave and reduced the distance to Tacoma by {{convert|9.3|mi|km|1}}.{{cite news |date=January 15, 1928 |title=New Highway To Tacoma To Clip Off Miles |page=1 |work=The Seattle Times}}{{cite news |date=March 27, 1927 |title=One Side of New Highway To Tacoma To Be Paved |page=14 |work=The Seattle Times}}

US 99 was originally routed north from Downtown Seattle on 4th Avenue, Westlake Avenue, 7th Avenue, and Dexter Avenue, crossing the Lake Washington Ship Canal on the Fremont Bridge before continuing onto Fremont Avenue.{{cite news |date=November 2, 1930 |title=Traffic Does Not Justify Expenses of Park Slashing |page=12 |work=The Seattle Times}} A high-level crossing of the Ship Canal to replace the existing drawbridges was proposed in the 1920s as the "final link" in the Pacific Highway.{{cite news |date=September 21, 1924 |title=Bridge Traffic Is Problem; Two New Structures Favored |page=1 |work=The Seattle Times}}{{cite news |last=Ross Gardner |first=James |date=June 29, 2011 |title=The Girl on the Bridge |url=https://www.seattlemet.com/news-and-city-life/2011/06/seattle-aurora-bridge-suicide-prevention-july-2011 |work=Seattle Met |access-date=October 8, 2018}} The {{convert|132|ft|m|adj=mid|-high}} bridge was funded by the state, county, and municipal governments and approved for construction in 1927.{{cite news |date=January 26, 1927 |title=$1,500,000 State Aid Is Asked For Stone Way Span |page=4 |work=The Seattle Times}}{{cite news |date=March 6, 1928 |title=New Bridge To Relieve Traffic on Fremont Span |page=2 |work=The Seattle Times}} Construction on the bridge began in 1929 and was completed on February 22, 1932, during a dedication ceremony that named it the George Washington Memorial Bridge.{{cite news |date=February 23, 1932 |title=Huge Crowd At Rites As Bridge Opens |page=13 |work=Seattle Post-Intelligencer |url=https://blog.seattlepi.com/seattle911/files/library/aurora_dedication_PDF_400.pdf |url-status=dead |archive-url=https://web.archive.org/web/20181009054636/https://blog.seattlepi.com/seattle911/files/library/aurora_dedication_PDF_400.pdf |archive-date=October 9, 2018 |access-date=October 8, 2018}} The bridge was sited on Aurora Avenue, which was expanded into a limited-access expressway that extended south to Denny Way and north through Woodland Park to North 65th Street.{{cite web |last=Ott |first=Jennifer |date=September 13, 2011 |title=Alaskan Way Viaduct, Part 1: Early Transportation Planning |url=https://historylink.org/File/9925 |work=HistoryLink |access-date=October 8, 2018}}{{cite news |date=November 24, 1929 |title=Denny Regrade Intersections Draws Realty Interest |page=32 |work=The Seattle Times}} The expressway on the north side of the bridge was completed in May 1933 after a public debate over its routing through Woodland Park, which was opposed by The Seattle Times and conservationists.{{cite news |date=May 14, 1933 |title=Aurora Avenue Will Be Thrown Wide Open Today |page=3 |work=The Seattle Times}}{{cite news |date=October 5, 1930 |title=Map Shows Adequate Arteries To Aurora Span |page=10 |work=The Seattle Times}} The debate was settled after the passing of a city council ordinance in June 1930 and a ballot measure in November that approved the through-park route.{{cite web |last=Oldham |first=Kit |date=February 17, 2007 |title=Seattle City Council votes to build Aurora Avenue through Woodland Park on June 30, 1930. |url=https://historylink.org/File/8093 |work=HistoryLink |access-date=October 8, 2018}}

{{see also|Alaskan Way Viaduct}}

{{multiple image

|align=right

|direction=vertical

|total_width=280

|caption_align=left

|image1=Seattle - Alaskan Way Viaduct under construction - 1952.gif

|alt1=Construction of an elevated highway through an urban neighborhood with mid-rise buildings, seen in black-and-white. A mobile crane is seen towering over workers laying down wood forms.

|caption1=Alaskan Way Viaduct construction near South Main Street, seen in April 1952

|image2=Seattle - Battery Street tunnel under construction, 1953.jpg

|alt2=Construction workers observe an open trench formed for a tunnel next to a brick-and-stone building. A concrete and steel framework is being placed over the open trench.

|caption2=Construction of the Battery Street Tunnel at 4th Avenue, seen in July 1953

}}

Within Downtown Seattle, US 99 was routed along 4th Avenue, connecting to the north with the Aurora Avenue expressway via 7th Avenue and to the south with East Marginal Way near Boeing Field.{{cite map |year=1950 |title=State of Washington Highway Map |author=Rand McNally |publisher=Washington State Highway Commission |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll18/id/9/rec/8 |via=WSDOT Library Digital Collections |access-date=October 8, 2018}}{{cite map |title=Street Map of Seattle |year=1947 |author=H.M. Gousha Company |publisher=Standard Oil of California |scale=1 inch = 0.7 mi}} An alternate route was designated in the early 1950s along 1st Avenue, rejoining the highway in Georgetown. Congestion and difficulty in directing freight trucks through downtown led to proposals for a bypass route for US 99 as early as 1928 along Railroad Avenue on the city's waterfront. Railroad Avenue, later renamed Alaskan Way, was rebuilt in the 1930s as part of the federal government's improvements to the city seawall and became the primary bypass route for through traffic, experiencing major congestion as a result.

Formal proposals to build "motor viaducts" bypassing the city along Alaskan Way were submitted by the city engineering department in 1937 and supported by automobile and traffic safety groups.{{cite news |date=December 2, 1937 |title=Traffic Survey Urges Viaducts |page=3 |work=The Seattle Times}}{{cite news |date=June 30, 1938 |title=Alaskan Way By-Pass Asked |page=36 |work=The Seattle Times}} The bypass viaduct gained popularity following the end of World War II and engineering work was approved in 1947, with construction funds sourced from the city and the Federal-Aid Highway Act of 1944.{{cite web |last=Ott |first=Jennifer |date=October 27, 2011 |title=Alaskan Way Viaduct, Part 2: Planning and Design |url=http://historylink.org/File/9951 |work=HistoryLink |access-date=October 8, 2018}} A double-deck elevated design was chosen to accommodate the six lanes that would displace railroads along the east side of Alaskan Way.{{cite news |last=Willix |first=Doug |date=May 11, 1947 |title=Alaskan Way Viaduct May Be 2-Decked |page=17 |work=The Seattle Times}} Construction on the Alaskan Way Viaduct began on February 6, 1950, and the first section between Railroad Way and Elliott Avenue opened to traffic on April 4, 1953.{{cite web |last=Ott |first=Jennifer |date=December 19, 2011 |title=First section of Seattle's Alaskan Way Viaduct opens on April 4, 1953. |url=http://historylink.org/File/9982 |work=HistoryLink |access-date=October 8, 2018}}{{cite news |date=April 5, 1953 |title=Alaskan Way Viaduct Opened To Traffic |page=1 |work=The Seattle Times}} It cost approximately $8 million to construct (equivalent to ${{Format price|{{Inflation|US-GDP|8000000|1953}}}} in {{Inflation-year|US-GDP}} dollars),{{inflation-fn|US-GDP}} using pile-driven columns and a pair of moving gantry cranes to lift sections of the roadway from street level.{{cite news |date=February 24, 1951 |title=Waterfront Viaduct To Be Finished in Fall |page=2 |work=The Seattle Times}}

The Battery Street Tunnel, connecting the viaduct with the Aurora Avenue expressway, was opened to traffic on July 24, 1954, and cost $2.8 million to construct (equivalent to ${{Format price|{{Inflation|US-GDP|2800000|1954}}}} in {{Inflation-year|US-GDP}} dollars).{{inflation-fn|US-GDP}}{{cite news |last=Heilman |first=Robert |date=July 25, 1954 |title=Battery St. Subway Opened as Sefair Lane |page=1 |work=The Seattle Times}} A {{convert|2.3|mi|km|adj=mid}} extension of the viaduct, linking south to a surface freeway and US 99 at East Marginal Way, cost $7.6 million to construct (equivalent to ${{Format price|{{Inflation|US-GDP|7600000|1954}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} and opened on September 3, 1959.{{cite news |date=September 3, 1959 |title=Viaduct Extension Opened Officially |page=1 |work=The Seattle Times}} The southern extension eased congestion at the Railroad Way terminus and was used by a daily average of 25,000 vehicles within days of opening and 37,000 vehicles by the end of the year.{{cite news |date=September 9, 1959 |title=Congestion In Extension Of Viaduct Eased |page=47 |work=The Seattle Times}} A series of ramps connecting the viaduct to the Spokane Street Viaduct were completed in January 1960,{{cite web |last=Ott |first=Jennifer |date=December 3, 2011 |title=Alaskan Way Viaduct, Part 3: Building the Viaduct |url=http://historylink.org/File/9978 |work=HistoryLink |access-date=October 8, 2018}} followed by a downtown offramp to Seneca Street in November 1961 and onramp from Columbia Street in February 1966.{{cite news |date=November 28, 1961 |title=Traffic Moves Smoothly in New Seneca St. Ramp |page=4 |work=The Seattle Times}}{{cite news |last=Willix |first=Douglas |date=January 27, 1966 |title=Columbia St. Viaduct Ramp To Be Opened |page=55 |work=The Seattle Times}} The state government had prepared to build a set of ramps from the viaduct to US 10 (later part of I-90) near Connecticut Street,{{cite news |date=December 19, 1955 |title=Progress In Traffic-Relief Projects Told |page=22 |work=The Seattle Times}} but plans for the freeway were delayed in the 1960s and eventually abandoned,{{cite news |date=March 6, 1967 |title=Expressway-Link Need Cited |page=24 |work=The Seattle Times}}{{cite news |last1=Wilson |first1=John |last2=Wilson |first2=Marshall |date=June 11, 1970 |title=Taxpayers Ante $4 Million For Abandoned Expressway |page=A1 |work=The Seattle Times}} leaving the ramps unused.{{cite news |last=Kelly |first=Tom |date=February 19, 1984 |title=Did voters kill solution to snarls? |page=D8 |work=The Seattle Times}}{{cite web |last=Ott |first=Jennifer |date=December 26, 2011 |title=Seattle's Columbia Street on-ramp to the Alaskan Way Viaduct opens to traffic on February 1, 1966. |url=https://www.historylink.org/File/9977 |work=HistoryLink |access-date=October 8, 2018}}

The viaduct was initially signed as part of U.S. Route 99 Alternate and US 99 Bypass until 1959, when US 99 was formally switched to the viaduct after the completion of the southern extension.{{cite map |year=1956 |title=Shell Street Guide of Seattle and Tacoma |author=H.M. Gousha Company |publisher=Shell Oil Company |scale=1 inch = 0.7 mi |url=https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~212302~5500344 |via=David Rumsey Historical Map Collection |access-date=October 8, 2018}}{{cite news |date=September 3, 1959 |title=Viaduct's Traffic Flow Changed |page=21 |work=The Seattle Times}} 4th Avenue was signed as a business route of US 99 and also carried a section of US 10 to its terminus at the north end of the Battery Street Tunnel.{{cite map |author=H. M. Gousha Company |year=1966 |title=Street Map of Seattle |scale=1 inch = 0.7 mi |publisher=Standard Oil Company of California |url=https://www.flickr.com/photos/tigerzombie/5069068935/sizes/o/ |access-date=December 23, 2018}} The East Marginal Way route through the Boeing Field area was heavily congested due to traffic heading to Boeing facilities, leading to proposals in the 1950s to build a new expressway on the west side of the Duwamish River.{{cite news |date=July 10, 1957 |title=W. Marginal Way Expressway Changes O.K'd |page=11 |work=The Seattle Times}} Construction of the two-lane West Marginal Way expressway began in November 1958 and was completed in July 1959, including grade-separated interchanges and bridges at South 118th Street, 14th Avenue South, and South Cloverdale Street.{{cite news |date=August 1959 |title=Construction To Bypass Heavy Boeing Traffic To Be Completed Soon in South Seattle |page=19 |work=Washington Highway News |volume=8 |issue=7 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/3493/ |via=WSDOT Library Digital Collections |access-date=October 9, 2018}} The expressway split from US 99 at South 118th Street and connected to 1st Avenue at the south end of the viaduct using the First Avenue South Bridge, which opened in 1956 with the intent of becoming part of US 99.{{cite news |last=Schear |first=Dwight |date=September 23, 1956 |title=Long-Awaited First Avenue South Bridge Opened |page=4 |work=The Seattle Times}} In March 1959, the state government approved $3 million in funds (equivalent to ${{Format price|{{Inflation|US-GDP|3000000|1959}}}} in {{Inflation-year|US-GDP}} dollars){{inflation-fn|US-GDP}} for an expansion project that would widen the West Marginal Way expressway to four lanes.{{cite news |last=Cunningham |first=Ross |date=March 22, 1959 |title=$160,000,000 State Highway Program Is Given Approval |page=8 |work=The Seattle Times}} The expansion was completed in 1968,{{cite news |date=July 1966 |title=Full Speed Ahead at Duwamish |page=15 |work=Washington Highway News |volume=13 |issue=2 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/5113/ |via=WSDOT Library Digital Collections |access-date=October 9, 2018}}{{cite news |date=January 1968 |title=Construction Roundup |page=16 |work=Washington Highway News |volume=15 |issue=1 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/5336/ |via=WSDOT Library Digital Collections |access-date=October 9, 2018}} and was signed as US 99 Temporary and later State Route 99T after the 1964 state highway renumbering.{{cite web |author=C. G. Prahl |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 |url-status=dead |archive-url=https://web.archive.org/web/20201030155114/https://wsdot.wa.gov/sites/default/files/2005/04/26/Identification-of-state-highways.pdf |archive-date=October 30, 2020 |access-date=October 9, 2018}}

File:US 99 shield at 1st & Columbia (18603502263).jpg until its removal in 2019|alt=A set of green highway signs reading "Southbound US 99" and "Waterfront" seen above a street intersection.]]

The state legislature authorized planning of a tolled expressway from Tacoma to Everett in 1953, with the intent of building a grade-separated bypass of US 99.{{cite news |last=Cunningham |first=Ross |date=February 3, 1952 |title=Knotty Financial, Traffic Problems Face Building Freeway Through Seattle |page=12 |work=The Seattle Times}}{{cite news |last=Dugovich |first=William |date=May 1967 |title=Seattle's Superfreeway |pages=2–5 |work=Washington Highways |publisher=Washington State Department of Highways |volume=14 |issue=2 |oclc=29654162 |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll1/id/5246 |via=WSDOT Library Digital Collections |access-date=October 9, 2018}} The tollway plan was superseded three years later by the Interstate Highway Program, which was authorized by the federal government and included a north–south freeway through the Seattle area replacing US 99.{{cite news |last=Cunningham |first=Ross |date=December 5, 1956 |title=State High Court's Decision Means No Expressway Tolls |page=15 |work=The Seattle Times}} The route was designated as Interstate 5 in 1957 and planning for the Seattle Freeway began at the same time using federal funds.{{cite news |last=Hittle |first=Leroy |date=October 9, 1957 |title=State's Two Major Highways To Be Renumbered In Defense System |page=1 |work=Port Angeles Evening News |agency=Associated Press |url=https://www.newspapers.com/clip/21044010/interstate_renumbering/ |via=Newspapers.com |access-date=October 9, 2018}}{{cite web |last=Becker |first=Paula |date=April 30, 2003 |title=First part of Seattle Freeway (Interstate 5) route receives federal funding on October 1, 1957. |url=https://www.historylink.org/File/4166 |work=HistoryLink |access-date=October 9, 2018}}

The first section of the Tacoma–Seattle–Everett freeway to be built was in southern Tacoma and was opened to traffic in October 1959. The Tacoma sections opened in October 1962 from the Puyallup River to the Kent–Des Moines Road (now SR 516) in Midway,{{cite news |date=October 10, 1962 |title=Tacoma-Midway Link In Freeway Opened |page=1 |work=The Seattle Times}} and in October 1964 in downtown Tacoma.{{cite news |date=October 30, 1964 |title=Tacoma Freeway Section Dedicated |page=26 |work=The Seattle Times |agency=Associated Press}} Construction of the Seattle section began in 1958 with work on the Ship Canal Bridge, which was opened to traffic on December 18, 1962.{{cite web |last=Long |first=Priscilla |date=May 27, 2001 |title=Lake Washington Ship Canal Bridge (Interstate 5) opens to traffic in December 1962. |url=https://www.historylink.org/File/3312 |work=HistoryLink |access-date=October 10, 2018}} The northern approach to Downtown Seattle was opened the following August to coincide with the completion of the Evergreen Point Floating Bridge and SR 520.{{cite news |date=August 28, 1963 |title=Rosellini Snips Ribbon to Open New Floating Bridge |page=C |work=The Seattle Times}} A {{convert|20|mi|km|adj=mid}} section of the freeway traveling from North Seattle to southern Snohomish County and Everett was opened to traffic on February 3, 1965.{{cite news |last=Davis |first=Don |date=February 3, 1965 |title=New Freeway Now Open |page=A1 |work=The Everett Herald}} The freeway connecting Midway to the south side of Downtown Seattle was opened on January 31, 1967, completing the final section of the urban freeway.{{cite news |last=Heilman |first=Robert |date=January 31, 1967 |title=Ceremony Opens Final Freeway Link |page=1 |work=The Seattle Times}} I-5 itself was completed two years later with the opening of the section between Everett and Marysville on May 14, 1969.{{cite news |last=Mansfield |first=Tom |date=May 14, 1969 |title=I-5 Opened Today |page=A1 |work=The Everett Herald}}

The state government introduced a new highway numbering system in 1964 to align with the Interstates and prepare for the decommissioning of U.S. routes.{{cite news |date=January 16, 1964 |title=Times Troubleshooter: New Route Numbers |page=10 |work=The Seattle Times}} PSH 1 was replaced with US 99, which remained as a temporary designation on various freeway sections until I-5 was fully completed.{{cite news |last=Hauptli |first=Jack |date=February 23, 1964 |title=Highway Department Plays The Numbers Game! |pages=10–11 |work=The Seattle Times}} US 99 was decommissioned at a meeting of the American Association of State Highway Officials on June 24, 1969, shortly after the full completion of I-5 within Washington state.{{AASHTO minutes |year=1969S |page=8 |link=yes |access-date=September 16, 2018}} While most US 99 signs were removed, an overhead sign in Downtown Seattle at the Columbia Street onramp to the Alaskan Way Viaduct remained until the viaduct was demolished in 2019.{{cite news |last=Banel |first=Feliks |date=August 15, 2018 |title=Searching for 'ghost signs' in Seattle |url=https://mynorthwest.com/1081314/searching-ghost-signs-seattle/ |publisher=KIRO Radio |access-date=October 8, 2018}}

During the 1970 codification of the new highway system, the state legislature created State Route 99 (SR 99) to delay transferring ownership and maintenance of the highway to local jurisdictions.{{cite book |date=February 24, 1970 |title=Session Laws of the State of Washington, 1970 1st extraordinary session |chapter=Chapter 51: State Highways—Route Numbers |page=356 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1970ex1c51.pdf |publisher=Washington State Legislature |access-date=October 9, 2018}}{{cite news |last=Burt |first=Lyle |date=May 23, 1969 |title=New Force Develops Against Highway Construction |page=14 |work=The Seattle Times}} SR 99 was created from a section of US 99 that ran from Fife to the Broadway Interchange in Everett, and was retained as a permanent addition to the state highway system in 1971 due to the corridor's importance to state affairs.{{cite book |date=May 18, 1971 |title=Session Laws of the State of Washington, 1971 1st extraordinary session |chapter=Chapter 73: State Highway Routes Numbers |page=524 |chapter-url=http://leg.wa.gov/CodeReviser/documents/sessionlaw/1971ex1c73.pdf |publisher=Washington State Legislature |access-date=October 9, 2018}}{{cite report |date=December 1970 |title=Legislative Study: SR 99 Tacoma to Marysville, Pierce–King–Snohomish Counties |pages=2–6 |publisher=Washington State Highway Commission, Washington State Department of Highways |url=https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll10/id/3161/ |via=WSDOT Library Digital Collections |access-date=December 18, 2018}} A provision in the 1971 law allows for the abandonment of the Fife–Federal Way section of SR 99 after the completion of the SR 509 freeway extension. Instead of continuing north into Everett on Evergreen Way, SR 99 was routed northeasterly on Everett Mall Way, a section of the Broadway Cut-off (also named Diagonal Way) that opened in June 1954.{{cite news |date=June 29, 1954 |title=Broadway Cut-Off Opened to Travel |page=1 |work=The Everett Herald |url=https://www.newspapers.com/article/the-everett-daily-herald-broadway-cut-of/139577785/ |via=Newspapers.com |accessdate=January 25, 2024}}{{cite book |last=O'Donnell |first=Lawrence E. |year=1993 |title=Everett Past and Present: A Centennial History of Everett |page=80 |publisher=K&H Printers |isbn=978-0-89716-275-3 |oclc=436832753}}

File:International Boulevard in Tukwila (31003195156).jpg, formerly part of SR 99 until a jurisdictional transfer in 2004|alt=An aerial view of a suburban street with several traffic lanes and traffic lights amid strip malls and gas stations.]]

Sections of SR 99 in North Seattle along Aurora Avenue and in South King County declined economically after the opening of Interstate 5, losing businesses amid increased crime.{{cite news |last=Gillie |first=John |date=October 19, 2008 |title=South King's face-lift on 99 |page=D1 |work=The News Tribune}} It became a notorious haven for drug dealers, prostitutes, the homeless, and strip clubs by the 1970s and 1980s.{{cite news |last=Gruener |first=Posey |date=December 20, 2015 |title=Why Is There So Much Prostitution On Aurora Avenue In Seattle? |url=https://www.kuow.org/stories/why-there-so-much-prostitution-aurora-avenue-seattle |publisher=KUOW |access-date=December 18, 2018}}{{cite news |last=Sullivan |first=Jennifer |date=January 17, 2008 |title=Prostitutes, drugs chased from Aurora corridor by group's patrols |page=A1 |url=https://archive.seattletimes.com/archive/?date=20080117&slug=gain17m |work=The Seattle Times |access-date=December 18, 2018}} The {{convert|17|mi|km|adj=mid}} stretch from Federal Way to Tukwila in South King County, popularly known as the "SeaTac Strip", was where the Green River Killer (Gary Ridgway) picked up many of his victims in the 1980s.{{cite news |last=Kamb |first=Lewis |date=February 7, 2002 |title=A new look to old haunts |page=A1 |work=Seattle Post-Intelligencer}}{{cite news |last=Smith |first=Carlton |date=December 12, 2001 |title=Highway 99: A boulevard full of ghosts |url=https://archive.seattletimes.com/archive/20011212/thestrip12m0/highway-99-a-boulevard-full-of-ghosts |work=The Seattle Times |url-status=live |archive-url=https://web.archive.org/web/20181219090846/http://community.seattletimes.nwsource.com/archive/?date=20011212&slug=thestrip12m0 |archive-date=December 19, 2018 |access-date=December 18, 2018}}{{cite news |last=Tizon |first=Tomas Alex |author-link=Alex Tizon |date=December 19, 2003 |title=Green River Killer Given Life Sentence |page=A25 |url=https://www.latimes.com/archives/la-xpm-2003-dec-19-na-green19-story.html |work=Los Angeles Times |url-status=live |archive-url=https://web.archive.org/web/20121212080950/http://articles.latimes.com/2003/dec/19/nation/na-green19 |archive-date=December 12, 2012 |access-date=December 18, 2018}} The highway was also unsafe for pedestrians and cross-traffic due to the lack of crossings and improper management of utility lines and overgrown foliage.

In an effort to clean up sections of the corridor, various cities have undertaken reconstruction projects in the 1990s and 2000s to turn the highway into a landscaped boulevard.{{cite news |last=Lange |first=Larry |date=June 12, 2002 |title=A city in conflict over 'Main Street' |page=A1 |work=The Seattle Times}} In southern King County, the cities of Federal Way, SeaTac, and Tukwila drew up redevelopment plans that were largely built out in the 2000s, reducing traffic collisions and crime while improving the area's appearance. After being denied permission to plant trees along SR 99, the city of Tukwila requested control of the highway within its city limits and was granted a jurisdictional transfer in 2004 by the state legislature, allowing them to redevelop {{convert|2.4|mi|km}} of International Boulevard into a new street with traffic calming features.{{cite news |last=McNichols |first=Joshua |date=May 14, 2018 |title=How Tukwila stole 2.5 miles of Highway 99 from state control |url=https://www.kuow.org/stories/how-tukwila-stole-25-miles-highway-99-state-control |publisher=KUOW |access-date=December 21, 2018}}

The city of Shoreline was incorporated in 1995 and made the redevelopment of Aurora Avenue into an early priority, completing its $140 million modernization and multi-use trail project in stages between 2008 and 2017.{{cite news |date=March 3, 2008 |title=Shoreline celebrates completion of Aurora and Interurban Trail projects |url=https://www.heraldnet.com/uncategorized/shoreline-celebrates-completion-of-aurora-and-interurban-trail-projects/ |work=The Everett Herald |access-date=December 21, 2018}} The project included new traffic signals, BAT lanes, underground utility lines, and two pedestrian bridges.{{cite web |title=Aurora Corridor Project |url=http://www.shorelinewa.gov/government/projects-initiatives/completed-projects/aurora-corridor-project |publisher=City of Shoreline |access-date=December 21, 2018}} Edmonds plans to add widened sidewalks with planted buffer zones, new crosswalks, and turn lane pockets to its {{convert|2.5|mi|km|adj=mid}} section of SR 99 beginning in 2022.{{cite news |last=Salyer |first=Sharon |date=August 28, 2017 |title=Edmonds has big plans for its Highway 99 improvements |url=https://www.heraldnet.com/news/edmonds-has-big-plans-for-its-highway-99-improvements/ |work=The Everett Herald |access-date=December 21, 2018}}{{cite news |last=Thompson |first=Joseph |date=February 10, 2020 |title=Edmonds nears phase 1 of renovations to crash-prone Highway 99 |url=https://www.heraldnet.com/news/edmonds-nears-phase-1-of-renovations-to-crash-prone-highway-99/ |work=The Everett Herald |access-date=February 11, 2020}} The city of Seattle also plans to improve its section of Aurora Avenue North, but funding shortages and the timing of WSDOT repaving projects have led to a lack of sidewalks along some sections of the street.{{cite news |last=Adolph |first=Carolyn |date=March 28, 2018 |title=The state is repaving Aurora. That's a chance to build sidewalks. But no |url=https://www.kuow.org/stories/state-repaving-aurora-thats-chance-build-sidewalks-no |publisher=KUOW |access-date=December 21, 2018}}{{cite news |last=Holt |first=Gordy |date=January 28, 2006 |title='Urban village' at Bitter Lake lacks amenity: Sidewalks |page=B1 |url=https://www.seattlepi.com/local/article/Urban-village-at-Bitter-Lake-lacks-amenity-1194192.php |work=Seattle Post-Intelligencer |access-date=December 21, 2018}} The Move Ahead Washington package, passed in 2022, includes $50 million in funds to rebuild sections of Aurora Avenue to include sidewalks, bicycle lanes, and landscaping.{{cite news |last=Lindblom |first=Mike |date=March 25, 2022 |title=$50M experiment aims to make Aurora Avenue more welcoming for bicyclists, pedestrians |url=https://www.seattletimes.com/seattle-news/transportation/can-seattles-aurora-avenue-be-pedestrian-friendly-a-50m-experiment-aims-to-find-out/ |work=The Seattle Times |accessdate=July 26, 2022}}

The Aurora Bridge, part of the expressway linking Aurora Avenue to downtown Seattle, was the site of frequent suicide jumps until a set of emergency phones and new fences were installed in 2011 at a cost of $4.6 million to deter would-be jumpers.{{cite news |last=Bobrowsky |first=February 9, 2011 |title=Aurora Bridge fence is nearly finished |page=B1 |url=http://old.seattletimes.com/html/localnews/2014166543_suicidefence09m.html |work=The Seattle Times |url-status=dead |archive-url=https://web.archive.org/web/20181222082322/http://old.seattletimes.com/html/localnews/2014166543_suicidefence09m.html |archive-date=December 22, 2018 |access-date=December 21, 2018}}{{cite news |last=Murphy |first=Kim |date=March 8, 2010 |title=In Seattle, a suicide barrier for a deadly bridge |page=A1 |url=https://www.latimes.com/archives/la-xpm-2010-mar-08-la-na-aurora-bridge8-2010mar08-story.html |work=Los Angeles Times |url-status=live |archive-url=https://web.archive.org/web/20151019013220/http://articles.latimes.com/2010/mar/08/nation/la-na-aurora-bridge8-2010mar08 |archive-date=October 19, 2015 |access-date=December 21, 2018}} The bridge and its expansion joints underwent a major seismic retrofit that was completed in 2012 at a cost of $5.7 million;{{cite news |last=Lange |first=Larry |date=June 6, 2011 |title=Aurora Bridge earthquake work has to be redone |url=https://www.seattlepi.com/local/transportation/article/Aurora-Bridge-earthquake-work-has-to-be-redone-1412237.php |work=Seattle Post-Intelligencer |access-date=December 21, 2018}} the retrofit was followed by a repainting and repaving project that was completed in two stages between 2016 and 2018 at a cost of $35 million.{{cite web |title=SR 99 - George Washington Bridge - Painting (Stage 2) & Paving |url=https://www.wsdot.wa.gov/Projects/SR99/AuroraBridgePainting/default.htm |publisher=Washington State Department of Transportation |url-status=dead |archive-url=https://web.archive.org/web/20210509111304/https://wsdot.wa.gov/Projects/SR99/AuroraBridgePainting/default.htm |archive-date=May 9, 2021 |access-date=December 21, 2018}}{{cite news |date=May 4, 2018 |title=Aurora Bridge getting 15,000 gallons of paint |url=https://www.djc.com/news/co/12110801.html |work=Seattle Daily Journal of Commerce |url-access=subscription |access-date=December 21, 2018}} On September 24, 2015, a collision between an amphibious Duck tour vehicle and a charter bus on the Aurora Bridge killed four people and injured 50 more.{{cite news |last=Johnson |first=Kirk |date=September 25, 2015 |title=College Students Killed in Seattle Bus Crash Were New to the Campus and the Country |page=A12 |url=https://www.nytimes.com/2015/09/26/us/national-transportation-officials-to-investigate-fatal-bus-crash-in-seattle.html |work=The New York Times |access-date=December 21, 2018}} The incident raised questions regarding the safety of Aurora Bridge, which lacks a median barrier and is the narrowest six-lane bridge in the state, with a lane width of {{convert|9.5|ft|m}}.{{cite news |last1=Lindblom |first1=Mike |last2=Baker |first2=Mike |date=September 25, 2015 |title=Span's narrow lanes a longtime safety concern |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/spans-narrow-lanes-a-longtime-safety-concern/ |work=The Seattle Times |access-date=December 21, 2018}} Other sections of Aurora Avenue were retrofitted to install median barriers in 1973,{{cite news |last=Barr |first=Robert A. |date=February 14, 1973 |title=Another chapter of Aurora Avenue history unfolds |page=C7 |work=The Seattle Times}} and the state government considered a 2003 plan to put barriers on the bridge and relocate the sidewalks to compensate for the additional weight but ultimately deferred any improvements. In the aftermath of the crash and its three-year-long court case, WSDOT and the Seattle Department of Transportation have disagreed over whether to install a center barrier or median zipper system, and which agency would be responsible for funding either option.

{{main|Alaskan Way Viaduct replacement tunnel}}

File:Cypress collapsed.jpg in Oakland, California, triggered investigations into the seismic vulnerability of the Alaskan Way Viaduct.|alt=A collapsed elevated freeway with the upper deck resting on the lower deck and several pillars destroyed. Several people with hard hats are seen investigating the scene.]]

Proposals to replace the Alaskan Way Viaduct date back to the 1970s during attempts to revitalize the city's waterfront for tourism and recreation rather than traditional industrial uses.{{cite web |last=Ott |first=Jennifer |date=December 19, 2011 |title=Alaskan Way Viaduct, Part 4: Replacing the Viaduct |url=https://www.historylink.org/File/9983 |work=HistoryLink |access-date=December 18, 2018}} A similar double-decker freeway, the Cypress Street Viaduct in Oakland, California, collapsed during the Loma Prieta earthquake in 1989 and killed 42 people, leading to intensified calls to replace the viaduct due to the realized earthquake risk.{{cite news |last=Werner |first=Larry |date=October 19, 1989 |title=Quake could topple Alaskan Way Viaduct |page=A5 |work=Seattle Post-Intelligencer}} A 1995 study commissioned by the state government after the Kobe earthquake found vulnerabilities in the Alaskan Way Viaduct's design that could cause severe damage and collapse during a major earthquake, along with liquefaction risks due to the underlying reclaimed land that the highway was built on.{{cite news |last=Penhale |first=Ed |date=July 20, 1995 |title=Earthquake study finds the viaduct on extra shaky ground |page=A1 |work=Seattle Post-Intelligencer}}{{cite news |last=Roberts |first=Gregory |date=March 5, 2007 |title=Quake threat key in viaduct debate |page=A1 |url=https://www.seattlepi.com/local/transportation/article/Quake-threat-key-in-viaduct-debate-1230115.php |work=Seattle Post-Intelligencer |access-date=December 18, 2018}} The study estimated that it would cost $118 million (equivalent to ${{Format price|{{Inflation|US-GDP|118000000|2000}}}} in {{Inflation-year|US-GDP}} dollars) to demolish the viaduct, $344 million (equivalent to ${{Format price|{{Inflation|US-GDP|344000000|2000}}}} in {{Inflation-year|US-GDP}} dollars) to retrofit the structure for earthquake resistance, and $530 million (equivalent to ${{Format price|{{Inflation|US-GDP|530000000|2000}}}} in {{Inflation-year|US-GDP}} dollars) to build a new elevated freeway to replace it;{{inflation-fn|US-GDP}}{{cite news |last=Lange |first=Larry |date=August 16, 2000 |title=Alaskan Way Viaduct's future again on state agenda |page=B1 |work=Seattle Post-Intelligencer}} other options included replacing the freeway with a tunnel or a surface boulevard with public transit on Alaskan Way, similar to San Francisco's Embarcadero.{{cite news |last=Hatcher |first=Candy |date=June 6, 2001 |title=Let's take waterfront cue from Bay Area |page=B1 |work=Seattle Post-Intelligencer}}{{cite news |last=Foster |first=George |date=January 16, 1997 |title=Options for the Alaskan Way Viaduct: State report spells out some bleak facts |page=B1 |work=Seattle Post-Intelligencer}}

On February 28, 2001, the Nisqually earthquake struck the Seattle area with strong shaking that caused signs of visible damage on the Alaskan Way Viaduct.{{cite news |last=Jamieson |first=Robert L. Jr. |date=March 1, 2001 |title=6.8 Shocker: 40-second jolt rocks homes, buckles roads |page=A1 |url=https://www.seattlepi.com/seattlenews/article/2-28-01-The-day-Seattle-shook-6107661.php |work=Seattle Post-Intelligencer |access-date=December 19, 2018}} The freeway was shut down for inspections, which found small cracks and other minor damage to non-structural elements that allowed it to reopen within 26 hours.{{cite news |last=Foster |first=George |date=March 2, 2001 |title=Viaduct replacement at least a decade off |page=A1 |work=Seattle Post-Intelligencer}} Four more closures were ordered later in March and April due to pieces of concrete dropping onto the streets below, requiring emergency repairs to add steel rods to reinforce the columns.{{cite news |last=Foster |first=George |date=March 31, 2001 |title=Another viaduct chunk drops |page=B1 |work=Seattle Post-Intelligencer}}{{cite news |last=Foster |first=George |date=April 17, 2001 |title=More weekend viaduct closures |page=B1 |work=Seattle Post-Intelligencer}} The first repairs were completed in November at a cost of $1.8 million and a set of new vehicle weight restrictions were implemented;{{cite news |last=Foster |first=George |date=October 10, 2001 |title=Viaduct repairs to be finished next month |page=B2 |work=Seattle Post-Intelligencer}} in total, $14.5 million was spent on various repairs due to earthquake damage.{{cite news |last=Diltz |first=Colin |date=November 22, 2018 |title=Seattle has changed: See the Alaskan Way Viaduct under construction in the 1950s |url=https://www.seattletimes.com/seattle-news/transportation/seattle-has-changed-see-the-alaskan-way-viaduct-take-shape-in-the-1950s/ |work=The Seattle Times |access-date=December 25, 2018}} Annual inspections and continued monitoring found that the earthquake had caused settling of up to {{convert|4|in|cm}} into the soil and weakened connections between the columns and highway decks.{{cite news |last=Andersen |first=Peggy |date=April 2, 2005 |title=Alaskan viaduct shifts a bit, but not enough to merit fix |url=https://www.spokesman.com/stories/2005/apr/02/alaskan-viaduct-shifts-a-bit-but-not-enough-to/ |work=The Spokesman-Review |agency=Associated Press |access-date=December 21, 2018}} Additional investigations also found unrelated damage to the underlying seawall, which would need to be rebuilt to prevent a resulting collapse of the viaduct.{{cite news |last=Lange |first=Larry |date=February 13, 2002 |title=Elliott Bay seawall called vulnerable |page=B1 |work=Seattle Post-Intelligencer}}

An ongoing state study investigating a viaduct replacement strategy was accelerated by the state legislature using $5 million in funds,{{cite news |last=Thomas |first=Ralph |date=September 19, 2005 |title=Who'll be to blame if viaduct, 520 bridge collapse? |page=A1 |url=http://old.seattletimes.com/html/localnews/2002504687_viaductmorality19m.html |work=The Seattle Times |url-status=dead |archive-url=https://web.archive.org/web/20181222125459/http://old.seattletimes.com/html/localnews/2002504687_viaductmorality19m.html |archive-date=December 22, 2018 |access-date=December 21, 2018}} while a separate engineering study suggested immediate demolition of the structure due to a 1-in-20 chance of collapse in an earthquake within the next decade.{{cite news |last=Gilmore |first=Susan |date=June 28, 2001 |title=Viaduct needs to go, engineers tell state |page=A1 |work=The Seattle Times}}{{cite news |last=Foster |first=George |date=March 9, 2001 |title=New urgency in study of viaduct |page=B1 |work=Seattle Post-Intelligencer}} In late 2001, WSDOT began work on an environmental impact statement (EIS) for the viaduct replacement project using emergency funds from the state legislature and consulted the city government and community leaders to generate concepts.{{cite news |last=Pryne |first=Eric |date=February 13, 2002 |title=Fixing road an option, but city would still have 'a 1950s highway' |page=B1 |work=The Seattle Times}} By the following year, a set of 76 concepts organized into four general alternatives were presented for public feedback.{{cite web |date=October 2010 |title=Alaskan Way Viaduct Replacement Project History Report |page=8 |url=https://www.wsdot.wa.gov/projects/viaduct/Media/Default/Documents/Environmental/2010SDEISAppendixS.pdf |work=Alaskan Way Viaduct Replacement Project 2010 Supplemental Draft Environmental Impact Statement |publisher=Washington State Department of Transportation |ref={{SfnRef|Alaskan Way Viaduct Replacement Project History Report|2010}} |access-date=December 22, 2018}} Among the options were an elevated freeway similar to the current viaduct and several tunnel concepts, including a bored tunnel, a two-level cut-and-cover tunnel, and a mined tunnel carrying one direction of traffic.{{cite news |last=Lange |first=Larry |date=March 22, 2002 |title=Planners zero in on 4 options |page=A1 |work=Seattle Post-Intelligencer}} Five finalist options were paired with the seawall replacement and evaluated in June 2002, with costs ranging from $3.5 billion for a rebuilt viaduct to $8.8–$11.6 billion for various tunnel designs.{{cite news |last=Sunde |first=Scott |date=June 4, 2002 |title=Billions pile up in road costs |page=A1 |work=Seattle Post-Intelligencer}}

File:Ivar's during 2015 replacement of Seattle Central Waterfront Seawall - 03.jpg, pictured in 2015|alt=An open trench with a temporary steel bridge separates a boardwalk business from a parking lot.]]

The tunnel plan was endorsed by WSDOT and the city council based on public support for waterfront revitalization, but design changes would be needed to bring down its cost.{{cite news |last=Lange |first=Larry |date=July 18, 2002 |title=Tunnel favored to replace viaduct |page=A1 |work=Seattle Post-Intelligencer}}{{cite news |last=Eskenazi |first=Stuart |date=June 15, 2002 |title=Aesthetics drives campaign against viaduct |page=B1 |work=The Seattle Times}} After voters rejected a statewide gas tax referendum that would have funded a portion of the project's cost, WSDOT and the city government drafted new cost-saving concepts for a shorter tunnel and a surface boulevard that were included in the five options evaluated by the draft EIS in 2004.{{cite news |last=Lindblom |first=Mike |date=December 4, 2002 |title=Viaduct alternatives include boulevard or smaller tunnel |page=B1 |work=The Seattle Times}}{{cite news |last=Gilmore |first=Susan |date=April 1, 2004 |title=Milestone in replacing viaduct: Environmental report outlines costs, construction times for 5 alternatives |page=B1 |work=The Seattle Times}} The six-lane, $4 billion tunnel option was chosen as the preferred alternative by WSDOT in late 2004, despite backlash from activists groups who favored a rebuilt viaduct or a waterfront boulevard.{{cite news |last=Lange |first=Larry |date=December 7, 2004 |title=Viaduct is out; tunnel is in |page=A1 |work=Seattle Post-Intelligencer}}

The state legislature passed an $8.5 billion gas tax program in 2005, allocating $2 billion in funding for the viaduct replacement.{{cite news |last=Gaudette |first=Karen |date=April 28, 2005 |title=Eastside lobbying pays off for I-405 project |page=B1 |url=https://www.seattletimes.com/seattle-news/eastside-lobbying-pays-off-for-i-405-project/ |work=The Seattle Times |access-date=December 22, 2018}} A supplemental EIS was prepared in 2006 to include new project requirements for the Battery Street Tunnel area and evaluate the cut-and-cover tunnel and elevated options. A pair of advisory, non-binding ballot measures was held in March 2007 to find a consensus between the $2.8 billion elevated replacement supported by Governor Christine Gregoire and a smaller four-lane tunnel with surface public transit improvements that would cost $3.4 billion and was supported by Mayor Greg Nickels; Nickel's "hybrid tunnel" proposal was rejected by Gregoire and state legislators prior to the vote based on operational and safety problems identified by WSDOT.{{cite news |last=Lange |first=Larry |date=February 16, 2007 |title=Seattle will get its viaduct vote |page=B1 |work=Seattle Post-Intelligencer}}{{cite news |last1=Garber |first1=Andrew |last2=Gilmore |first2=Susan |last3=Lindblom |first3=Mike |date=February 14, 2007 |title=State says no tunnel; mayor still wants vote |page=A1 |url=http://old.seattletimes.com/html/localnews/2003571128_viaductreport14m0.html |work=The Seattle Times |access-date=December 22, 2018}} Both options were rejected by voters, with 70 percent opposed to the tunnel and 55 percent opposed to the elevated concept.{{cite news |last1=Galloway |first1=Angela |last2=Lange |first2=Larry |date=March 14, 2007 |title=No and no: Voters rejecting both viaduct options |page=A1 |work=Seattle Post-Intelligencer}}

The governments of Washington state, King County, and Seattle agreed to re-evaluate the planning process for the viaduct replacement and split the main proposals from essential safety and traffic improvements that would be included in all alternatives. A $915 million package of projects was approved for immediate construction, beginning with work to strengthen sinking columns in late 2007 and repairs to the Battery Street Tunnel the following year.{{cite news |last=Lange |first=Larry |date=May 8, 2007 |title=Late-summer start for viaduct work |page=B1 |work=Seattle Post-Intelligencer}}{{cite news |last=Gilmore |first=Susan |date=October 14, 2007 |title=4 columns on viaduct to be stabilized early |page=B2 |work=The Seattle Times}} Although the column strengthening project was declared successful, further inspections found that the Columbia Street onramp had sunk an additional {{convert|1/8|in|cm}} during the nearby construction.{{cite news |last=Carlton Harrell |first=Debera |date=March 28, 2008 |title=No new damage seen on sinking viaduct |page=B1 |work=Seattle Post-Intelligencer}}{{cite news |last=Lange |first=Larry |date=June 21, 2008 |title=Viaduct sinks a little bit more |page=B1 |work=Seattle Post-Intelligencer}} The southernmost stretch of the viaduct, between Holgate and King streets, was demolished in October 2011 and replaced with a six-lane elevated freeway that opened the following year at a cost of $115 million.{{cite news |last=Lindblom |first=Mike |date=October 23, 2011 |title=Thousands say goodbye to viaduct |page=A1 |url=http://old.seattletimes.com/html/localnews/2016584114_viaduct23m.html |work=The Seattle Times |access-date=December 23, 2018}}{{cite press release |date=July 17, 2012 |title=South-end viaduct replacement will wrap up one year early, on budget |url=http://www.wsdot.wa.gov/News/2012/07/17_EarlyH2K.htm |publisher=Washington State Department of Transportation |url-status=dead |archive-url=https://web.archive.org/web/20130603065611/http://www.wsdot.wa.gov/News/2012/07/17_EarlyH2K.htm |archive-date=June 3, 2013 |access-date=December 23, 2018}} Seattle voters approved a bond measure in 2012 to replace the Alaskan Way Seawall;{{cite news |last=Johnson |first=Kirk |date=December 5, 2012 |title=Engineering Projects Will Transform Seattle, All Along the Waterfront |page=A18 |url=https://www.nytimes.com/2012/12/05/us/projects-to-transform-seattle-all-along-the-waterfront.html |work=The New York Times |access-date=December 23, 2018}} the project began construction in 2013 and was completed in 2017 at a cost of $410 million, running 21 percent overbudget.{{cite news |last=Takeo |first=Ryan |date=May 24, 2017 |title=New Seattle seawall aims to improve waterfront salmon habitat |url=https://www.king5.com/article/tech/science/environment/new-seattle-seawall-aims-to-improve-waterfront-salmon-habitat/442750032 |publisher=KING 5 News |access-date=December 23, 2018}}{{cite news |last=Beekman |first=Daniel |date=August 22, 2015 |title=Seawall project $71 million over budget |page=B1 |url=https://www.seattletimes.com/seattle-news/politics/seawall-project-over-budget-but-mayor-insists-no-new-taxes/ |work=The Seattle Times |access-date=December 23, 2018}}

The state government announced a new timeline for the project in January 2008, with Governor Gregoire declaring her intention to demolish the viaduct by 2012 regardless of Seattle's approval.{{cite news |last=McGann |first=Chris |date=January 4, 2008 |title=Gregoire: 'Watch me' tear down the viaduct |page=A1 |url=https://www.seattlepi.com/local/transportation/article/Gregoire-Watch-me-tear-down-the-viaduct-1260638.php |work=Seattle Post-Intelligencer |access-date=December 22, 2018}} Eight new concepts for a four-lane replacement were developed by June from a set of priorities developed for SR 99, I-5, and public transit in downtown.{{Sfn|Alaskan Way Viaduct Replacement Project History Report|2010|p=35}} The eight options included two surface boulevards with transit improvements, a one-way couplet, a set of two elevated freeways, an elevated freeway with a rooftop park, and three tunnels: a cut-and-cover tunnel, a lidded trench, and a deep-bored tunnel.{{cite news |last=Lange |first=Larry |date=June 27, 2008 |title=8 viaduct options detailed |page=B1 |url=https://www.seattlepi.com/local/transportation/article/8-viaduct-options-detailed-1277807.php |work=Seattle Post-Intelligencer |access-date=December 22, 2018}} Several early concepts, including a bridge across Elliott Bay and a complete rebuild of the double-decked viaduct, were rejected by the panel of public officials.{{cite news |last=Gilmore |first=Susan |date=June 27, 2008 |title=State narrows the viaduct proposals to 8 |page=B4 |work=The Seattle Times}} The final decision was delayed until after the gubernatorial election, but would have to meet an end-of-year deadline imposed by the state legislature.{{cite news |last=Lange |first=Larry |date=September 26, 2008 |title=Viaduct details won't be known till after election |page=B3 |url=https://www.seattlepi.com/local/transportation/article/Viaduct-details-won-t-be-known-till-after-election-1286406.php |work=Seattle Post-Intelligencer |access-date=December 22, 2018}} In December 2008, two finalists were chosen for further study and consideration by the state legislature: a $2.3 billion elevated freeway and the $2.2 billion surface-transit option.{{cite news |last=Lange |first=Larry |date=December 12, 2008 |title=Viaduct options: down to 2 |page=A1 |url=https://www.seattlepi.com/local/transportation/article/Viaduct-options-Down-to-2-1294430.php |work=Seattle Post-Intelligencer |access-date=December 22, 2018}}

While the deep-bored tunnel was not chosen as one of the two finalists, it remained popular with tunnel activists and was considered separately due to its $4.25 billion cost (equivalent to ${{Format price|{{Inflation|US-GDP|4250000000|2009}}}} in {{Inflation-year|US-GDP}} dollars).{{inflation-fn|US-GDP}}{{cite news |last=Lindblom |first=Mike |date=January 1, 2009 |title=Viaduct tunnel idea rises again |page=B1 |url=http://old.seattletimes.com/html/localnews/2008579379_boredtunnel01m.html |work=The Seattle Times |access-date=December 22, 2018}} On January 13, 2009, Governor Gregoire signed an agreement with Mayor Nickels and King County Executive Ron Sims to ratify the deep-bored tunnel as the replacement for the Alaskan Way Viaduct, to be completed by 2015. $2.8 billion would be covered by state gas taxes and federal funds, leaving a $1.4 billion shortfall to be filled by the local government and potential tolls.{{cite news |last=Lindblom |first=Mike |date=January 13, 2009 |title=Gregoire announces tunnel plans; car-tab taxes to pay for more transit |page=A1 |url=http://old.seattletimes.com/html/localnews/2008622393_webviaduct13m.html |work=The Seattle Times |access-date=December 22, 2018}}{{cite news |last1=McGann |first1=Chris |last2=Lange |first2=Larry |date=January 13, 2009 |title=Tolls and taxes would help to pay for tunnel |page=A1 |url=https://www.seattlepi.com/local/transportation/article/Tolls-and-taxes-would-help-to-pay-for-tunnel-1297345.php |work=Seattle Post-Intelligencer |access-date=December 22, 2018}} The state legislature passed a bill in April 2009 to commit $2.8 billion in state funding for the tunnel project, which Governor Gregoire signed the following month.{{cite news |last=Garber |first=Andrew |date=April 23, 2009 |title=House approves plan to replace viaduct with a tunnel |page=A1 |url=http://old.seattletimes.com/html/localnews/2009106821_webviaduct22m.html |work=The Seattle Times |access-date=December 22, 2018}}{{cite news |last=Cohen |first=Aubrey |date=May 12, 2009 |title=Viaduct-replacing tunnel bill gets governor's signature |url=https://www.seattlepi.com/local/transportation/article/Viaduct-replacing-tunnel-bill-gets-governor-s-1303886.php |work=Seattle Post-Intelligencer |access-date=December 22, 2018}} In total, more than 90 alternatives were considered before the final agreement was reached in 2009.{{cite web |title=Alaskan Way Viaduct Project: History |url=http://www.wsdot.wa.gov/Projects/Viaduct/About/History |publisher=Washington State Department of Transportation |url-status=dead |archive-url=https://web.archive.org/web/20201112030336/https://www.wsdot.wa.gov/Projects/Viaduct/About/History |archive-date=November 12, 2020 |access-date=December 22, 2018}}

The tunnel project received $300 million in funds from the Port of Seattle in exchange for design input on the surface boulevard that would replace Alaskan Way. Neighborhood and environmental activist Mike McGinn was elected mayor in 2009, largely on an anti-tunnel platform, and threatened to veto project agreements until the state took responsibility for cost overruns that would fall upon Seattle.{{cite news |last=Yardley |first=William |date=April 10, 2011 |title=Seattle Ponders (Some More) the Wisdom of Replacing a Roadway |page=A16 |url=https://www.nytimes.com/2011/04/10/us/10tunnel.html |work=The New York Times |access-date=December 23, 2018}}{{cite news |last=Gutierrez |first=Scott |date=June 2, 2010 |title=Gregoire, McGinn spar over viaduct tunnel |url=https://www.seattlepi.com/local/article/Gregoire-McGinn-spar-over-viaduct-tunnel-887321.php |work=Seattle Post-Intelligencer |access-date=December 23, 2018}} The city council approved a non-binding resolution to authorize the tunnel project, pending the outcome of contract bidding, which was completed in December 2010 with the selection of Seattle Tunnel Partners (STP), a consortium led by Dragados USA.{{cite news |last=Grygiel |first=Chris |date=December 8, 2010 |title=State announces winner in two-team viaduct tunnel race |url=https://www.seattlepi.com/local/article/State-announces-winner-in-two-team-viaduct-tunnel-871467.php |work=Seattle Post-Intelligencer |access-date=December 23, 2018}} STP presented a $1.09 billion plan to use a {{convert|58|ft|m|adj=mid|-diameter}} tunnel boring machine, the world's widest, to complete the tunnel by late 2015.{{cite news |last=Lindblom |first=Mike |date=December 10, 2010 |title=Winning team promises to build a wider Highway 99 tunnel, a year sooner |page=A1 |url=http://old.seattletimes.com/html/localnews/2013636817_99tunnel10m.html |work=The Seattle Times |access-date=December 23, 2018}} WSDOT signed the tunnel construction contract in January 2011, sending a set of contractor agreements to the city council for approval.{{cite news |last=Lindblom |first=Mike |date=January 7, 2011 |title=$1.4 billion tunnel contract is signed; opposition still working to halt project |page=B4 |url=http://old.seattletimes.com/html/localnews/2013867057_99tunnel07m.html |work=The Seattle Times |access-date=December 23, 2018}}

The state's agreements were approved by the city council in February 2011, shortly before being symbolically vetoed by Mayor McGinn; the veto was overridden by the end of the month—the 10th anniversary of the Nisqually earthquake—with an 8–1 city council majority.{{cite news |last=Thompson |first=Lynn |date=February 17, 2011 |title=Mayor vetoes tunnel plan, as expected |page=B1 |url=http://old.seattletimes.com/html/localnews/2014261163_tunnelveto18m.html |work=The Seattle Times |access-date=December 23, 2018}}{{cite news |last=Thompson |first=Lynn |date=March 1, 2011 |title=Seattle City Council overrides McGinn's tunnel veto |page=B1 |url=http://old.seattletimes.com/html/localnews/2014356539_tunnel01m.html |work=The Seattle Times |access-date=December 23, 2018}} McGinn joined other tunnel opposition groups to file a referendum questioning whether the city council had the authority to approve the state and federal agreements.{{cite news |last=Yardley |first=William |date=August 19, 2011 |title=Seattle, After Decade of Debate, Approves Tunnel |page=A13 |url=https://www.nytimes.com/2011/08/19/us/19seattle.html |work=The New York Times |access-date=December 23, 2018}} The referendum was initially blocked by a lawsuit filed by the city, but was approved and placed on the August 2011 ballot by a county judge.{{cite news |last1=Thompson |first1=Lynn |last2=Lindblom |first2=Mike |date=May 21, 2011 |title=Judge: Anti-tunnel measure going on August ballot |page=A1 |url=http://old.seattletimes.com/html/localnews/2015105379_tunnelpreview21m.html |work=The Seattle Times |access-date=December 23, 2018}} The referendum was approved by 58 percent of voters on August 16, 2011, authorizing the city's agreements with WSDOT.{{cite news |date=August 17, 2011 |title=Voters backing Seattle tunnel; fight may finally be over |page=A1 |url=http://old.seattletimes.com/html/localnews/2015928327_elextunnel17m.html |work=The Seattle Times |access-date=December 23, 2018}} The Federal Highway Administration completed its analysis of the project's final EIS and issued its record of decision with WSDOT later that month, allowing pre-construction activities to begin.{{cite news |last=Gutierrez |first=Scott |date=August 23, 2011 |title=SR 99 deep bore tunnel gets federal approval |url=https://www.seattlepi.com/local/transportation/article/SR-99-deep-bore-tunnels-gets-federal-approval-2137635.php |work=Seattle Post-Intelligencer |access-date=December 23, 2018}}

{{main|Bertha (tunnel boring machine)}}

File:Tunnel Tour (31861116610).jpg the tunnel boring machine and the unfinished interior of the SR 99 tunnel, seen in January 2017|alt=The inside of a large concrete cylinder with steel cables and forms on the sides. Ahead is a massive structure with several floors of machinery and a large yellow tube at the top.]]

After the demolition of the viaduct's southernmost stretch and its lanes were realigned onto an adjacent bypass in 2012, crews began excavation of a {{convert|420|ft|m|adj=mid|-long}} launch pit to house the tunnel boring machine.{{cite news |last=Lindblom |first=Mike |date=April 19, 2012 |title=Digging deep to drill Highway 99 tunnel |page=B1 |url=http://old.seattletimes.com/html/localnews/2018015629_99tunnel19lo.html |work=The Seattle Times |access-date=December 23, 2018}} Local officials, with the notable absence of Mayor Mike McGinn, participated in a ceremonial groundbreaking was held for the tunnel on June 20, 2012.{{cite news |last=Gutierrez |first=Scott |date=June 20, 2012 |title=McGinn absent at SR 99 tunnel groundbreaking |url=https://www.seattlepi.com/local/transportation/article/McGinn-skips-SR-99-tunnel-groundbreaking-3614165.php |work=Seattle Post-Intelligencer |access-date=December 23, 2018}} The {{convert|57|ft|m|adj=mid}} tunnel boring machine was manufactured by Hitachi Zosen in Osaka, Japan, and named "Bertha" in honor of Mayor Bertha Knight Landes.{{cite news |last=Lee |first=Jessica |date=March 10, 2017 |title=How did we get here? A look back on Seattle's tunnel machine Bertha |url=https://www.seattletimes.com/seattle-news/transportation/bertha-tunnel-boring-machine-history-viaduct-replacement/ |work=The Seattle Times |access-date=December 23, 2018}} Bertha arrived in Seattle on April 2, 2013, and its 40 pieces were assembled in the launch pit before tunnel boring began on July 30—setting a record for the world's largest tunnel boring machine.{{cite news |last=Lindblom |first=Mike |date=July 31, 2013 |title=Bertha's excavation mission beginning under downtown |url=http://old.seattletimes.com/html/localnews/2021505839_99tunnelxml.html |work=The Seattle Times |access-date=December 23, 2018}}

Tunnel boring was halted at {{convert|1,028|ft|m}} near South Main Street in December 2013 after the machine encountered an unknown object that caused it to overheat.{{cite news |last=Lindblom |first=Mike |date=December 10, 2013 |title=Highway 99 tunnel mystery may take drill rigs or divers to solve |page=A1 |url=http://old.seattletimes.com/html/localnews/2022433048_99tunnelobstructionxml.html |work=The Seattle Times |access-date=December 23, 2018}} The object was found to be a {{convert|119|ft|m|adj=mid}} steel pipe and well casing that was left behind by a groundwater research crew for the project in 2002.{{cite news |last=Lindblom |first=Mike |date=January 4, 2014 |title=Bertha's nemesis: 119-foot steel pipe |page=A1 |url=http://old.seattletimes.com/html/localnews/2022593902_berthametalxml.html |work=The Seattle Times |access-date=December 23, 2018}} The pipe caused extensive damage to Bertha's cutterhead and main bearing seal, requiring the excavation of a {{convert|120|ft|m|adj=mid}} rescue pit for repairs.{{cite news |last=La Ganga |first=Maria L. |date=December 23, 2014 |title=Seattle unsettled by massive drill tunneling through downtown |url=https://www.latimes.com/nation/la-na-seattle-sinking-20141223-story.html |work=Los Angeles Times |access-date=December 23, 2018}} Bertha reached the completed excavation pit in March 2015 and the machine's front end was disassembled and lifted to the surface to repair the damage, which was found to be more extensive than previously thought.{{cite news |last1=Lindblom |first1=Mike |last2=Kamb |first2=Lewis |date=February 20, 2015 |title=Bertha's punch to repair pit lifts hopes for tunnel progress |page=A10 |url=https://www.seattletimes.com/seattle-news/berthas-punch-to-repair-pit-lifts-hopes-for-tunnel-progress/ |work=The Seattle Times |access-date=December 23, 2018}}{{cite news |last=Lindblom |first=Mike |date=May 19, 2015 |title=Bertha repair will take longer — there are lots of broken parts |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/bertha-repair-will-take-longer-theres-more-damage/ |work=The Seattle Times |access-date=December 23, 2018}}

The repaired cutterhead was lowered into the access pit in August 2015 and tunnel boring resumed on December 22, 2015, reaching past the pit the following month.{{cite news |last=Lindblom |first=Mike |date=August 25, 2015 |title=Crews start moving Bertha's rebuilt cutter drive back into pit |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/easy-does-it-crews-gearing-up-to-put-berthas-rebuilt-cutter-drive-back-in-pit/ |work=The Seattle Times |access-date=December 23, 2018}}{{cite news |last=Lindblom |first=Mike |date=December 23, 2015 |title=Bertha back on the move after 2 years of delays |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/bertha-restarts-after-two-years-of-delays/ |work=The Seattle Times |access-date=December 23, 2018}} During the two-year halt in tunnel boring, public officials considered alternative plans to accelerate demolition of the viaduct while awaiting tunnel completion.{{cite news |last1=Beekman |first1=Daniel |last2=O'Sullivan |first2=Joseph |date=January 3, 2015 |title=Bertha's stall has politicians stuck for answers |url=https://www.seattletimes.com/seattle-news/bertharsquos-stall-has-politicians-stuck-for-answers/ |work=The Seattle Times |access-date=December 23, 2018}} The project was named one of the worst boondoggles in the United States by several transportation groups and critics, due in part to the stoppage and its high cost.{{cite news |last=Lindblom |first=Mike |date=September 18, 2014 |title=Seattle tunnel tops U.S. green group's 'boondoggle' list |url=http://blogs.seattletimes.com/today/2014/09/seattle-tunnel-tops-u-s-green-groups-boondoggle-list/ |work=The Seattle Times |access-date=December 23, 2018}} Tunnel boring was halted by Governor Jay Inslee in January 2016 due to the appearance of a sinkhole in Pioneer Square, but resumed the following month.{{cite news |last=Lindblom |first=Mike |date=February 24, 2016 |title=Bertha's on the move again, even if it's just 3 feet |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/shes-ba-ack-yes-berthas-on-the-move-once-again/ |work=The Seattle Times |access-date=December 23, 2018}} The machine passed under the Alaskan Way Viaduct in April 2016, requiring a closure while the structure was monitored for movement, and reached the halfway mark in October.{{cite news |last=Torres |first=Blanca |date=May 9, 2016 |title=Commuters, rejoice: Alaskan Way Viaduct reopens early |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/alaska-way-viaduct-opens-monday-ahead-of-schedule/ |work=The Seattle Times |access-date=December 23, 2018}}{{cite news |last=Lindblom |first=Mike |date=October 4, 2016 |title=Bertha's halfway done; if this keeps up, it could emerge in May |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/berthas-halfway-done-if-this-keeps-up-it-could-emerge-in-may-knock-on-wood/ |work=The Seattle Times |access-date=December 23, 2018}} Bertha completed its {{convert|1.75|mi|km|adj=mid}} bore on April 4, 2017, arriving at the north portal near Aurora Avenue for disassembly, which was completed in August.{{cite news |last=Lindblom |first=Mike |date=April 5, 2017 |title=Bertha's breakthrough just 'halftime' for tunnel project |page=A1 |url=https://www.seattletimes.com/seattle-news/transportation/sense-of-history-builds-as-tunnel-machine-bertha-inches-toward-daylight/ |work=The Seattle Times |access-date=December 23, 2018}}{{cite news |last=Lee |first=Jessica |date=August 23, 2017 |title=From disassembly pit, crews haul away last bits of Bertha |url=https://www.seattletimes.com/seattle-news/transportation/watch-from-disassembly-pit-crews-haul-away-last-bits-of-bertha/ |work=The Seattle Times |access-date=December 23, 2018}} The tunnel portals and their maintenance areas were completed while work on the double-decker freeway inside the tunnel progressed behind the machine.{{cite news |last=Lindblom |first=Mike |date=April 16, 2017 |title=Inside the Highway 99 tunnel: Bertha's done digging, but the roadway work rolls on |page=B1 |url=https://www.seattletimes.com/seattle-news/transportation/inside-highway-99-tunnel-bertha-roadwork-wsdot/ |work=The Seattle Times |access-date=December 23, 2018}}

The Alaskan Way Viaduct permanently closed on January 11, 2019, beginning a three-week realignment of ramps at the portals as ramps were prepared for the opening of the tolled downtown tunnel on February 4, 2019.{{cite news |last=Lindblom |first=Mike |date=January 11, 2019 |title=Goodbye, viaduct: The highway closes for good after 66 years on Seattle's waterfront |url=https://www.seattletimes.com/seattle-news/transportation/goodbye-viaduct-the-highway-closes-for-good-after-66-years-on-seattles-waterfront/ |work=The Seattle Times |access-date=January 11, 2019}}{{cite news |date=February 4, 2019 |title=SR 99 tunnel now open to traffic |url=http://www.wsdot.wa.gov/Projects/Viaduct/library/advisories-and-updates/sr-99-tunnel-now-open-to-traffic |publisher=Washington State Department of Transportation |access-date=February 4, 2019 |archive-date=February 4, 2019 |archive-url=https://web.archive.org/web/20190204174410/http://www.wsdot.wa.gov/Projects/Viaduct/library/advisories-and-updates/sr-99-tunnel-now-open-to-traffic |url-status=dead }} The remaining {{convert|1.4|mi|km|adj=mid}} section of the viaduct was demolished in stages between February and November 2019, with some of the {{convert|240|e6lbs|kg}} of rubble deposited into the Battery Street Tunnel as it was filled and sealed.{{cite news |last=Bushman |first=Sammi |date=November 19, 2019 |title=How to get your free piece of Seattle's Alaskan Way Viaduct |url=https://www.king5.com/article/news/local/the-viaduct-is-rubble-and-now-you-can-have-a-piece/281-c1db02b5-bc7a-4d6a-990c-c20bc3efddc2 |publisher=KING 5 News |access-date=November 20, 2019}}{{cite news |last=Lindblom |first=Mike |date=December 5, 2018 |title=Seattle's big demolition spectacle: How crews plan to pulverize the Alaskan Way Viaduct |url=https://www.seattletimes.com/seattle-news/transportation/final-plans-outlined-for-demolition-of-alaskan-way-viaduct/ |work=The Seattle Times |access-date=December 23, 2018}} A three-block section of Aurora Avenue between Denny Way and the new tunnel portal was raised and reconnected to cross-streets in 2019.{{cite news |last=Baruchman |first=Michelle |date=July 26, 2019 |title=Here's where 2 bus stops will move once construction is done in South Lake Union |url=https://www.seattletimes.com/seattle-news/transportation/construction-brings-closures-bus-relocations-at-denny-and-seventh-avenue-north-heres-how-to-navigate-the-area/ |work=The Seattle Times |access-date=April 5, 2020}} The Alaskan Way promenade and boulevard project is planned to cost $668 million and will be completed in 2024.{{cite news |last=Black |first=Tony |date=May 3, 2018 |title=Big changes ahead for Seattle's waterfront and downtown |url=https://www.king5.com/article/news/local/seattle/big-changes-ahead-for-seattles-waterfront-and-downtown/281-548490884 |publisher=KING 5 News |access-date=December 23, 2018}} The new boulevard will be eight lanes wide in some sections due to requirements placed by WSDOT for Colman Dock access and the Port of Seattle for truck access.{{cite news |last=Lindblom |first=Mike |date=November 16, 2016 |title='8-lane highway' on Seattle's waterfront? Critics challenge post-viaduct plan |url=https://www.seattletimes.com/seattle-news/transportation/8-lane-highway-for-seattles-future-alaskan-way-challenged/ |work=The Seattle Times |access-date=December 23, 2018}} The viaduct replacement megaproject is estimated to cost $3.3 billion, with $200 million of construction costs and additional funds for ongoing maintenance to be raised through tunnel tolls that began to be collected on November 9, 2019.{{cite news |last=Lindblom |first=Mike |date=November 12, 2019 |title=How is your Highway 99 toll money spent? A big chunk goes to collecting the tolls |url=https://www.seattletimes.com/seattle-news/transportation/how-is-your-highway-99-toll-money-spent-a-big-chunk-goes-to-collecting-the-tolls/ |work=The Seattle Times |access-date=November 20, 2019}}

In 2022, community activists from the South Park neighborhood proposed removing a freeway section of SR 99 between SR 599 and SR 509 to improve local air quality.{{cite news |last=Kroman |first=David |date=February 19, 2022 |title=Seattle residents drive movement to tear out Highway 99 in South Park |url=https://www.seattletimes.com/seattle-news/transportation/seattle-residents-drive-movement-to-tear-out-highway-99-in-south-park/ |work=The Seattle Times |accessdate=March 1, 2023}} A federal grant was announced the following year to study the impact of a possible removal or redesign of the highway through South Park.{{cite news |last=Kroman |first=David |date=March 1, 2023 |title=Feds award money to study removing Highway 99 in one Seattle neighborhood |url=https://www.seattletimes.com/seattle-news/transportation/feds-award-money-to-study-removing-highway-99-in-one-seattle-neighborhood/ |work=The Seattle Times |accessdate=March 1, 2023}}

File:SR 99 William P. Stewart Memorial Highway sign in Everett.jpg

The name of SR 99 differs from city to city, with several sections named the Pacific Highway and International Boulevard, a moniker invented by SeaTac for the 1990 Goodwill Games hosted by King County.{{cite news |last=Parrish |first=Linda W.Y. |date=July 17, 1990 |title=SeaTac rolls out the welcome mat |page=D3 |work=The Seattle Times}} In Seattle, the highway is known as East Marginal Way and Aurora Avenue North; in Everett, it uses Evergreen Way and Everett Mall Way.{{cite news |last=Gonzalez |first=Victor M. |date=May 16, 1997 |title=Poll solidly rejects F'way road renaming |page=A1 |work=Seattle Post-Intelligencer}}{{cite news |date=March 19, 1992 |title=Still today it's a road by any other name... |page=A14 |work=Seattle Post-Intelligencer}} A four-block section of former SR 99 between Denny Way and the new tunnel portal was renamed to 7th Avenue North and Borealis Avenue in early 2019 as part of the reconfiguration of Aurora Avenue.{{cite news |last=Groover |first=Heidi |date=January 29, 2019 |title=From Aurora to Borealis: Seattle City Council moves ahead with renaming avenue in South Lake Union |url=https://www.seattletimes.com/seattle-news/transportation/from-aurora-to-borealis-seattle-city-council-moves-ahead-with-renaming-aurora-avenue-in-south-lake-union/ |work=The Seattle Times |access-date=February 4, 2019}}

The United Daughters of the Confederacy unsuccessfully lobbied the state legislature in 1939 to designate the entirety of US 99 within the state as part of the national "Jefferson Davis Highway".{{cite news |last=Howe Verhovek |first=Sam |date=February 14, 2002 |title=Road Named for Jefferson Davis Stirs Spirited Debate |page=A20 |url=https://www.nytimes.com/2002/02/14/us/road-named-for-jefferson-davis-stirs-spirited-debate.html |work=The New York Times |access-date=December 18, 2018}}{{cite news |last=Ray |first=Susanna |date=January 23, 2002 |title=Jefferson Davis Highway here? Legislator outraged |url=https://www.heraldnet.com/news/jefferson-davis-highway-here-legislator-outraged/ |work=The Everett Herald |access-date=November 8, 2013}} A pair of granite markers were installed the following year in Blaine and Vancouver to commemorate the highway, allegedly to recognize Davis's contributions to the territorial development of Washington as U.S. Secretary of War.{{cite news |last=Porter |first=Mark |date=February 4, 2002 |title=Highway marker may be protected |page=A3 |work=The Bellingham Herald |agency=Associated Press}} The two markers were removed in 1998 and 2002, and are now located at the privately owned Jefferson Davis Park in Ridgefield.{{cite news |last=Littman |first=Adam |date=August 18, 2017 |title=Confederate monuments in Ridgefield defaced |url=https://www.columbian.com/news/2017/aug/18/paint-splashed-on-confederate-monuments-in-ridgefield/ |work=The Columbian |access-date=December 18, 2018}}

The State House of Representatives unanimously approved a bill in 2002 that would have removed Davis' name from the road, but it was deferred by a State Senate committee.{{cite news |last=Cook |first=Rebecca |date=March 5, 2002 |title=Legislation to rename highway dies |page=A1 |work=The Columbian |agency=Associated Press}} The attempted renaming, led by Snohomish representative Hans Dunshee, generated political controversy and death threats against legislators from people opposed to the bill. The bill was revived in May 2016 and was passed unanimously by both houses of the legislature, renaming SR 99 for William P. Stewart, an African-American Civil War veteran and early settler in Snohomish.{{cite news |last=Muhlstein |first=Julie |date=May 21, 2016 |title=Highway 99 renamed in honor of Snohomish settler William P. Stewart |url=https://www.heraldnet.com/news/highway-99-renamed-in-honor-of-snohomish-settler-william-p-stewart/ |work=The Everett Herald |access-date=December 18, 2018}} New highway signs for the William P. Stewart Memorial Highway were installed the following year, amid a new wave of Confederate monument removals.{{cite news |last=Muhlstein |first=Julie |date=August 16, 2017 |title=New Everett highway sign honors black Civil War soldier |url=https://www.heraldnet.com/news/new-highway-sign-in-everett-honors-civil-war-soldier/ |work=The Everett Herald |access-date=December 18, 2018}}

File:RapidRide A Line to FWTC Test Coach.jpg, operated by King County Metro between Federal Way and Tukwila|alt=A red-and-yellow articulated bus seen on a suburban street from a nearby sidewalk. The bus's front sign reads "[A] Federal Way TC".]]

SR 99 is a major regional public transit corridor and carries several bus rapid transit routes and a light rail line in SeaTac.{{cite map |title=Regional Transit Map Book |date=February 2014 |pages=8–11 |url=http://your.kingcounty.gov/ftp/gis/Web/VMC/transportation/RTMB/RTMB_all.pdf |format=PDF |publisher=Sound Transit |url-status=dead |archive-url=https://web.archive.org/web/20170728073922/http://your.kingcounty.gov/ftp/gis/Web/VMC/transportation/RTMB/RTMB_all.pdf |archive-date=July 28, 2017 |access-date=September 21, 2018}} The highway features bus lanes and business access and transit lanes (BAT lanes) in several locations to give buses traffic priority while retaining access to right turns.{{cite news |last=Slager |first=Melissa |date=September 29, 2018 |title=Holy traffic, bus driver! To the BAT lanes! |url=https://www.heraldnet.com/news/holy-traffic-bus-driver-to-the-bat-lanes/ |work=The Everett Herald |access-date=December 18, 2018}}{{cite news |last=Gilmore |first=Susan |date=October 23, 2002 |title=New dawn coming for Aurora Avenue? Changes eyed to cut number of accidents |page=B1 |url=https://archive.seattletimes.com/archive/20021023/aurora23m/new-dawn-coming-for-aurora-avenue-changes-eyed-to-cut-number-of-accidents |work=The Seattle Times |access-date=December 18, 2018}}

Pierce Transit route 500 runs on the SR 99 and Pacific Highway corridor between Tacoma Dome Station and Federal Way Transit Center. Through Federal Way and SeaTac, the highway is served by the RapidRide A Line, an {{convert|11|mi|km|adj=mid}} rapid bus route that debuted in 2010 and features enhanced bus stops and transit signal priority.{{cite press release |date=October 1, 2010 |title=Metro's new RapidRide "A" Line to connect Tukwila and Federal Way launches Oct. 2 |url=http://www.kingcounty.gov/transportation/kcdot/NewsCenter/NewsReleases/2010/October/nr100110_rapidride.aspx |publisher=King County Metro |url-status=dead |archive-url=https://web.archive.org/web/20110823170557/http://www.kingcounty.gov/transportation/kcdot/NewsCenter/NewsReleases/2010/October/nr100110_rapidride.aspx |archive-date=August 23, 2011 |access-date=December 18, 2018}} Sound Transit's Link light rail trains on the 1 Line run along elevated tracks above or near SR 99 from Angle Lake station to Tukwila International Boulevard station at the SR 518 interchange.{{cite map |date=September 2018 |title=Metro Transit System: Southwest Area |url=https://kingcounty.gov/~/media/depts/transportation/metro/maps/system/09222018/pdf/metro-system-map-sw |publisher=King County Metro |access-date=December 18, 2018 |archive-date=December 19, 2018 |archive-url=https://web.archive.org/web/20181219182158/https://kingcounty.gov/~/media/depts/transportation/metro/maps/system/09222018/pdf/metro-system-map-sw |url-status=dead }} The Alaskan Way Viaduct carried several non-stop routes connecting Downtown Seattle to West Seattle (including the RapidRide C Line) and Burien.{{cite map |date=September 2018 |title=Metro Transit System: Northwest Area |url=https://kingcounty.gov/~/media/depts/transportation/metro/maps/system/09222018/pdf/metro-system-map-nw |publisher=King County Metro |access-date=December 18, 2018 |archive-date=November 27, 2018 |archive-url=https://web.archive.org/web/20181127151858/https://kingcounty.gov/~/media/depts/transportation/metro/maps/system/09222018/pdf/metro-system-map-nw |url-status=dead }}

Aurora Avenue is served by the RapidRide E Line, which carried 18,000 passengers daily in 2017 and is the busiest bus route in the King County Metro system.{{cite news |last=Lindblom |first=Mike |date=April 26, 2018 |title=Get used to those crowded Metro buses: They won't get better quickly |url=https://www.seattletimes.com/seattle-news/transportation/metro-cant-add-all-the-bus-service-seattle-wants-to-buy-to-improve-service/ |work=The Seattle Times |access-date=December 18, 2018}} The E Line debuted in 2014, replacing Route 358—itself the successor to Route 359, which was retired in 1999 after a Metro bus was involved in a shooting and crashed off the Aurora Bridge.{{cite news |last=Lindblom |first=Mike |date=November 22, 2018 |title=Bus drivers will honor 'brother' fatally shot on the job |page=B2 |url=https://www.seattletimes.com/seattle-news/transportation/buses-will-pause-friday-to-remember-metro-transit-driver-fatally-shot-in-1998-on-aurora-bridge/ |work=The Seattle Times |access-date=December 18, 2018}}{{cite news |last1=Broom |first1=Jack |last2=Clarridge |first2=Christine |date=December 8, 1998 |title=Bus drivers honor one of their own |page=A1 |url=https://archive.seattletimes.com/archive/19981208/2787861/bus-drivers-honor-one-of-their-own----memorial-for-mark-mclaughlin |work=The Seattle Times |access-date=December 18, 2018}}{{cite news |last=Lindblom |first=Mike |date=February 15, 2014 |title=Aurora Avenue North bus now RapidRide |url=http://www.seattletimes.com/seattle-news/aurora-avenue-north-bus-now-rapidride/ |work=The Seattle Times |access-date=September 24, 2015}} The E Line terminates in Downtown Seattle and near the county line at the Aurora Village Transit Center, where Community Transit's route 101 and Swift Blue Line begins. Swift features off-board fare payment and longer spacing between stops, and runs from Shoreline to Everett Station via Evergreen Way.{{cite news |last=Lindblom |first=Mike |date=November 30, 2009 |title=Bus rapid transit launches today from Everett to Shoreline |url=http://old.seattletimes.com/html/localnews/2010386196_swift30m.html |work=The Seattle Times |access-date=September 24, 2015}}{{cite news |last=Sheets |first=Bill |date=November 24, 2009 |title=Swift buses ready for fast lane |url=https://www.heraldnet.com/news/seems-like-yesterday-692/ |work=The Everett Herald |access-date=December 18, 2018}} The Everett Mall Way section of SR 99 is served by Everett Transit route 7, which connects the Everett Mall to Downtown Everett and Everett Station.{{cite map |date=October 2021 |title=Everett Transit System Map |url=https://everetttransit.org/228/System-Map |publisher=Everett Transit |access-date=December 14, 2021}}

{{WAinttop|length_ref=}}

{{WAint

|county=Pierce

|cspan=2

|location=Fife

|mile=0.00

|road={{jct|state=WA|I|5|city1=Seattle|city2=Tacoma}}

}}

{{WAint

|location=Milton

|mile=1.62

|road=Porter Way

|notes=Former SR 514

}}

{{WAint

|county=King

|cspan=28

|location=Federal Way

|lspan=2

|mile=4.49

|road={{jct|state=WA|SR|18|dir1=east|to2=to|I|5|name1=South 348th Street|city1=Auburn|city2=North Bend}}

}}

{{WAint

|mile=7.72

|type=concur

|road={{jct|state=WA|SR|509|dir1=south|name1=South Dash Point Road|location1=Dash Point State Park}}

|notes=South end of SR 509 concurrency

}}

{{WAint

|location=Des Moines

|mile=11.84

|type=concur

|road={{jct|state=WA|SR|516|SR|509|dir2=north|to3=to|I|5|city1=Des Moines|city2=Kent}}

|notes=North end of SR 509 concurrency

}}

{{WAint

|location=SeaTac

|mile=15.11

|road={{jct|extra=airport}} South 182nd Street – Sea–Tac Airport

}}

{{WAint

|location1=SeaTac

|location2=Tukwila

|location_group=city

|mile=16.78

|road={{jct|state=WA|SR|518|to2=to|I|5|I|405|city1=Renton|city2=Burien}}

|notes=Interchange

}}

{{jctgap

|text=Gap in route, continues as Tukwila International Boulevard

}}

{{WAint

|location=Tukwila

|lspan=3

|mile=16.79

|mspan=2

|road={{jct|state=WA|SR|599|dir1=south|to2=to|I|5}}

|notes=Continuation south

}}

{{WAint

|mile=none

|road=South 116th Street / Tukwila International Boulevard

|notes=Interchange; south end of freeway section

}}

{{WAint

|mile=17.61

|road=West Marginal Place South

|type=incomplete

|notes=Northbound exit and entrance

}}

{{WAint

|location=Seattle

|lspan=4

|mile=18.63

|road=Des Moines Memorial Drive / 14th Avenue South

}}

{{WAint

|mile=19.22

|road=South Cloverdale Street

|type=incomplete

|notes=Northbound entrance only

}}

{{WAint

|mile=19.56

|type=incomplete

|road=South Kenyon Street – South Park

|notes=Southbound exit and entrance

}}

{{WAint

|mile=20.23

|road={{jct|state=WA|SR|509|dir1=south|road|West Marginal Way South|city1=Burien}}

|notes=Interchange

}}

{{jctbridge

|location_special=Duwamish River

|mile=20.27

|mile2=20.82

|bridge=First Avenue South Bridge

}}

{{WAint

|location=Seattle

|lspan=9

|mile=20.60

|mspan=2

|type=incomplete

|road={{jct|state=WA|to1=to|I|5}} via Michigan Street

|notes=Northbound exit and southbound entrance

}}

{{jctplace

|mile=none

|place=North end of freeway

}}

{{WAint

|mile=22.41

|mspan=2

|type=incomplete

|road=Spokane Street – West Seattle, Waterfront, Port Terminals

|notes=Northbound exit and southbound entrance

}}

{{jctplace

|mile=none

|place=South end of freeway

}}

{{WAint

|mile=22.80

|type=incomplete

|road=West Seattle Bridge – Harbor Island

|notes=Southbound exit and northbound entrance

}}

{{WAint

|mile=23.96

|type=incomplete

|road={{jct|state=WA|SR|519|to2=to|I|5|I|90|road|Alaskan Way South, South Dearborn Street|location1=Downtown Seattle}}

|notes=Southbound exit and northbound entrance

}}

{{jcttunnel

|mile=24.18

|mile2=26.26

|tunnel=Alaskan Way (SR 99) Tunnel

|type=ETC

}}

{{WAint

|mile=26.18

|type=incomplete

|road=Republican Street, 6th Avenue North – Mercer Street, Seattle Center

|notes=Northbound exit and southbound entrance

}}

{{WAint

|mile=26.44

|type=incomplete

|road=Aurora Avenue – Denny Way, Downtown Seattle

|notes=Southbound exit and northbound entrance; north end of freeway

}}

{{jctbridge

|location_special=Lake Union

|mile=27.75

|mile2=28.31

|bridge=George Washington Memorial Bridge

}}

{{WAint

|location=Seattle

|lspan=3

|mile=28.43

|road=North 38th Street

|notes=Interchange

}}

{{WAint

|mile=29.05

|road=North 46th Street

|notes=Interchange

}}

{{WAint

|mile=29.88

|road=North 63rd Street / Green Lake Way

|notes=Interchange

}}

{{WAint

|location1=Seattle

|location2=Shoreline

|location_group=city

|mile=34.05

|road={{jct|state=WA|SR|523|dir1=east|name1=North 145th Street|to2=to|I|5}}

}}

{{WAint

|county1=King

|county2=Snohomish

|location1=Shoreline

|location2=Edmonds

|location_group=city

|mile=37.07

|road={{jct|state=WA|SR-Spur|104|dir1=east|to2=to|SR|104|dir2=east|I|5|city1=Mountlake Terrace|city2=Lake Forest Park}}

}}

{{WAint

|county=Snohomish

|cspan=5

|location=Edmonds

|mile=37.18

|road={{jct|state=WA|SR|104|to2=to|I|5|city1=Edmonds|location2=Kingston Ferry|city3=Mountlake Terrace|city4=Lake Forest Park}}

|notes=Interchange

}}

{{WAint

|location=Lynnwood

|mile=40.42

|road={{jct|state=WA|SR|524|name1=196th Street Southwest}}

}}

{{WAint

|location=none

|mile=44.20

|road={{jct|state=WA|SR|525|to2=to|I|5|dir2=south|I|405|dir3=south|road|Alderwood Mall Parkway|city1=Mukilteo|location2=Whidbey Island Ferry}}

|notes=Interchange

}}

{{WAint

|location=Everett

|lspan=2

|mile=48.80

|mile2=48.97

|road={{jct|state=WA|I|5|city1=Seattle|location2=Vancouver, BC}}

}}

{{WAint

|mile=48.97

|road={{jct|state=WA|SR|526|dir1=west|SR|527|dir2=south|road|Broadway}}

|notes=Continues north as Broadway

}}

{{jctbtm|keys=concur,etc,incomplete}}

{{reflist}}

{{Attached KML|display=inline,title}}

• {{commons category-inline|Washington State Route 99}}
• [https://www.angelfire.com/wa2/hwysofwastate/sr099.html Highways of Washington State]
• [http://www.wsdot.wa.gov/Projects/Viaduct/ SR 99 Alaskan Way Viaduct Replacement Program]

{{Streets in Seattle}}

{{Authority control}}

{{DEFAULTSORT:Washington State Route 099}}

099

Category:Transportation in Pierce County, Washington

Category:Transportation in King County, Washington

Category:Transportation in Snohomish County, Washington

Category:Seattle metropolitan area

Category:U.S. Route 99