State Route 99 (SR 99), also known as the Pacific Highway, is a

state highway A state highway, state road, or state route (and the equivalent provincial highway, provincial road, or provincial route) is usually a road that is either ''numbered'' or ''maintained'' by a sub-national state or province. A road numbered by a ...

in the

Seattle metropolitan area The Seattle metropolitan area is an urban conglomeration in the U.S. state of Washington that comprises Seattle, its surrounding satellites and suburbs. It contains the three most populous counties in the state—King, Snohomish, and Pierce� ...

, part of the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sover ...

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

. It runs from

Fife Fife (, ; gd, Fìobha, ; sco, Fife) is a council area, historic county, registration county and lieutenancy area of Scotland. It is situated between the Firth of Tay and the Firth of Forth, with inland boundaries with Perth and Kinross (i ...

in the south to Everett in the north, passing through the cities of

Federal Way Federal Way is a city in King County, Washington, United States. One of the most recently incorporated cities in the county, its population was 101,030 at the 2020 census. Federal Way is the tenth-largest city in Washington and the fifth-larges ...

, SeaTac,

Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...

Shoreline A shore or a shoreline is the fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. In physical oceanography, a shore is the wider fringe that is geologically modified by the action of the body of water past a ...

, and

Lynnwood Lynnwood is a city in Snohomish County, Washington, United States. The city is part of the Seattle metropolitan area and is located north of Seattle and south of Everett, near the junction of Interstate 5 and Interstate 405. It is the four ...

. The route primarily follows arterial streets, including Aurora Avenue, and has several

freeway A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms ...

segments, including the tolled

SR 99 Tunnel The State Route 99 tunnel, also known as the Alaskan Way Viaduct replacement tunnel, is a bored highway tunnel in the city of Seattle, Washington, United States. The , double-decker tunnel carries a section of State Route 99 (SR 99) under ...

Downtown Seattle Downtown is the central business district of Seattle, Washington. It is fairly compact compared with other city centers on the U.S. West Coast due to its geographical situation, being hemmed in on the north and east by hills, on the west by ...

. SR 99 was officially named the William P. Stewart Memorial Highway by the state legislature in 2016, after a campaign to replace an unofficial moniker honoring Confederate president

Jefferson Davis Jefferson F. Davis (June 3, 1808December 6, 1889) was an American politician who served as the president of the Confederate States from 1861 to 1865. He represented Mississippi in the United States Senate and the House of Representatives as a ...

. SR 99 was originally a section of U.S. Route 99 (US 99), which was once the state's primary north–south highway. US 99 was created in 1926 and replaced earlier local roads that date back to the 1890s and state roads designated as early as 1913. The highway was moved onto the

Alaskan Way Viaduct The Alaskan Way Viaduct ("the viaduct" for short) was an elevated freeway in Seattle, Washington, United States, that carried a section of State Route 99 (SR 99). The double-decked freeway ran north–south along the city's waterfront for , ...

in 1953, replacing a congested stretch through Downtown Seattle, and other sections were built to expressway standards in the 1950s. US 99 was ultimately replaced by the Tacoma–Everett section of

Interstate 5 Interstate 5 (I-5) is the main north–south Interstate Highway on the West Coast of the United States, running largely parallel to the Pacific coast of the contiguous U.S. from Mexico to Canada. It travels through the states of Califor ...

(I-5), which opened in stages between 1965 and 1969. The route was de-certified in 1969 and SR 99 was created to keep segments of the highway under state control. After decades of crime on some sections of SR 99, various city governments funded projects to beautify the highway and convert it into a

boulevard A boulevard is a type of broad avenue planted with rows of trees, or in parts of North America, any urban highway. Boulevards were originally circumferential roads following the line of former city walls. In American usage, boulevards may ...

. A section of the highway in Tukwila was transferred to city control in 2004, creating a gap in the route between the interchanges of SR 518 and SR 599. The Alaskan Way Viaduct was closed on January 11, 2019, and was replaced with a downtown bored tunnel that opened on February 4, 2019. The replacement project was spurred by the

2001 Nisqually earthquake The 2001 Nisqually earthquake occurred at on February 28, 2001 and lasted nearly a minute. The intraslab earthquake had a moment magnitude of 6.8 and a maximum Mercalli intensity of VIII (''Severe''). The epicenter was in the southern Puget So ...

, which damaged the viaduct and left it vulnerable to further damage, as well as city plans to revitalize the Seattle waterfront. The $3 billion

megaproject A megaproject is an extremely large-scale investment project. According to the ''Oxford Handbook of Megaproject Management'', "Megaprojects are large-scale, complex ventures that typically cost $1 billion or more, take many years to develop and ...

was mired in planning delays for several years before construction began in 2011 with the partial demolition of the viaduct. The tunnel was constructed using

Bertha Bertha is a female Germanic name, from Old High German ''berhta'' meaning "bright one". It was usually a short form of Anglo Saxon names ''Beorhtgifu'' meaning "bright gift" or ''Beorhtwynn'' meaning "bright joy". The name occurs as a theonym, s ...

, the world's largest

tunnel boring machine A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may also be used for microtunneling. They can be designed to bore throu ...

at the time of its launch in 2013, which had a two-year halt and completed its bore in 2017. The viaduct was demolished in 2019, leaving room for an expanded park promenade on

Alaskan Way Alaskan Way, originally Railroad Avenue, is a street in Seattle, Washington, that runs along the Elliott Bay waterfront from just north of S. Holgate Street in the Industrial District—south of which it becomes East Marginal Way S.— to Broad S ...

that is planned to be completed in 2024.

Route description

SR 99 follows a section of former U.S. Route 99 (US 99) within the

, from

to southern Everett. 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. A section of the highway from Tukwila to

is also designated as a Highway of Statewide Significance by the state legislature. The

Washington State Department of Transportation The Washington State Department of Transportation (WSDOT or WashDOT, both ) is a governmental agency that constructs, maintains, and regulates the use of transportation infrastructure in the U.S. state of Washington (state), Washington. Establi ...

(WSDOT) estimates that average traffic volumes on SR 99, measured in terms of

average annual daily traffic Annual average daily traffic, abbreviated AADT, is a measure used primarily in transportation planning, transportation engineering and retail location selection. Traditionally, it is the total volume of vehicle traffic of a highway or road for a y ...

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 The First Avenue South Bridge is a pair of double-leaf bascule bridges built between 1956 and 1998 that carry State Route 99 over the Duwamish River Edmonds plans to add widened sidewalks with planted buffer zones, new crosswalks, and turn lane pockets to its section of SR 99 beginning in 2022. 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. 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. 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 phone An emergency telephone is a telephone, phone specifically provided for making calls to emergency services and is most often found in a place of special danger or where it is likely that there will be a need to make emergency calls. It is also so ...

s and new fences were installed in 2011 at a cost of $4.6 million to deter would-be jumpers. The bridge and its

expansion joint An expansion joint, or movement joint, is an assembly designed to hold parts together while safely absorbing temperature-induced expansion and contraction of building materials, and vibration, or to allow movement due to ground settlement or seis ...

s underwent a major

seismic retrofit Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with our recent exp ...

that was completed in 2012 at a cost of $5.7 million; 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. On September 24, 2015, a collision between an amphibious

Duck tour Duck tours are tours that take place on purpose-built Amphibious vehicle#Buses, amphibious tour buses and (modified) surplus amphibious military vehicles, like DUKWs (''"Ducks"'') and LARC-Vs. They are often offered as tourist attractions in ha ...

vehicle and a

charter bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...

on the Aurora Bridge killed four people and injured 50 more. 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 . Other sections of Aurora Avenue were retrofitted to install median barriers in 1973, 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 The Seattle Department of Transportation (SDOT) is a municipal government agency in Seattle, Washington that is responsible for the maintenance of the city's transportation systems, including roads, bridges, and public transportation. The agency ...

have disagreed over whether to install a center barrier or median zipper system, and which agency would be responsible for funding either option.

Viaduct replacement and tunnel project

Proposals and earthquake studies

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. A similar double-decker freeway, the

Cypress Street Viaduct The Cypress Street Viaduct, often referred to as the Cypress Structure or the Cypress Freeway, was a 1.6-mile-long (2.5 km), raised two-deck, multi-lane (four lanes per tier) freeway constructed of reinforced concrete that was originally pa ...

Oakland, California Oakland is the largest city and the county seat of Alameda County, California, United States. A major West Coast of the United States, West Coast port, Oakland is the largest city in the East Bay region of the San Francisco Bay Area, the third ...

, collapsed during the

Loma Prieta earthquake The 1989 Loma Prieta earthquake occurred on California's Central Coast on October 17 at local time. The shock was centered in The Forest of Nisene Marks State Park in Santa Cruz County, approximately northeast of Santa Cruz on a section of t ...

in 1989 and killed 42 people, leading to intensified calls to replace the viaduct due to the realized earthquake risk. A 1995 study commissioned by the state government after the

Kobe earthquake The , or Kobe earthquake, occurred on January 17, 1995, at 05:46:53 JST (January 16 at 20:46:53 UTC) in the southern part of Hyōgo Prefecture, Japan, including the region known as Hanshin. It measured 6.9 on the moment magnitude scale and had ...

found vulnerabilities in the Alaskan Way Viaduct's design that could cause severe damage and collapse during a major earthquake, along with

liquefaction In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics. It occurs both naturally and artificially. As an example of the ...

risks due to the underlying

reclaimed land Land reclamation, usually known as reclamation, and also known as land fill (not to be confused with a waste landfill), is the process of creating new Terrestrial ecoregion, land from oceans, list of seas, seas, Stream bed, riverbeds or lak ...

that the highway was built on. The study estimated that it would cost $118 million (equivalent to $ in dollars) to demolish the viaduct, $344 million (equivalent to $ in dollars) to retrofit the structure for earthquake resistance, and $530 million (equivalent to $ in dollars) to build a new elevated freeway to replace it; other options included replacing the freeway with a tunnel or a surface boulevard with

public transit Public transport (also known as public transportation, public transit, mass transit, or simply transit) is a system of transport for passengers by group travel systems available for use by the general public unlike private transport, typical ...

on Alaskan Way, similar to

San Francisco San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...

's Embarcadero. On February 28, 2001, the

Nisqually earthquake The 2001 Nisqually earthquake occurred at on February 28, 2001 and lasted nearly a minute. The intraslab earthquake had a moment magnitude of 6.8 and a maximum Mercalli intensity of VIII (''Severe''). The epicenter was in the southern Puget So ...

struck the Seattle area with strong shaking that caused signs of visible damage on the Alaskan Way Viaduct. 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. 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. The first repairs were completed in November at a cost of $1.8 million and a set of new vehicle weight restrictions were implemented; in total, $14.5 million was spent on various repairs due to earthquake damage. Annual inspections and continued monitoring found that the earthquake had caused settling of up to into the soil and weakened connections between the columns and highway decks. Additional investigations also found unrelated damage to the underlying

seawall A seawall (or sea wall) is a form of coastal defense constructed where the sea, and associated coastal processes, impact directly upon the landforms of the coast. The purpose of a seawall is to protect areas of human habitation, conservation ...

, which would need to be rebuilt to prevent a resulting collapse of the viaduct. An ongoing state study investigating a viaduct replacement strategy was accelerated by the state legislature using $5 million in funds, 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. 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. By the following year, a set of 76 concepts organized into four general alternatives were presented for public feedback. Among the options were an elevated freeway similar to the current viaduct and several tunnel concepts, including a

bored tunnel A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may also be used for microtunneling. They can be designed to bore thro ...

, a two-level

cut-and-cover A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube constr ...

tunnel, and a mined tunnel carrying one direction of traffic. 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.

Tunnel concept, advisory votes, and subprojects

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. After voters rejected a statewide

gas tax A fuel tax (also known as a petrol, gasoline or gas tax, or as a fuel duty) is an excise tax imposed on the sale of fuel. In most countries the fuel tax is imposed on fuels which are intended for transportation. Fuels used to power agricultural v ...

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. 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. The state legislature passed an $8.5 billion gas tax program in 2005, allocating $2 billion in funding for the viaduct replacement. 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 measure A referendum (plural: referendums or less commonly referenda) is a direct vote by the electorate on a proposal, law, or political issue. This is in contrast to an issue being voted on by a representative. This may result in the adoption of a ...

s was held in March 2007 to find a consensus between the $2.8 billion elevated replacement supported by Governor

Christine Gregoire Christine Gregoire (; née O'Grady; born March 24, 1947) is an American politician who served as the 22nd governor of Washington from 2005 to 2013. A member of the Democratic Party, she defeated Republican candidate Dino Rossi in 2004, and again ...

and a smaller four-lane tunnel with surface public transit improvements that would cost $3.4 billion and was supported by Mayor

Greg Nickels Gregory J. Nickels (born August 7, 1955) is an American politician who served as the 51st mayor of Seattle, Washington. He took office on January 1, 2002 and was reelected to a second term in 2005. In August 2009, Nickels finished third in the p ...

; 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. Both options were rejected by voters, with 70 percent opposed to the tunnel and 55 percent opposed to the elevated concept. 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. Although the column strengthening project was declared successful, further inspections found that the Columbia Street onramp had sunk an additional during the nearby construction. 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. Seattle voters approved a

bond measure A municipal bond, commonly known as a muni, is a bond issued by state or local governments, or entities they create such as authorities and special districts. In the United States, interest income received by holders of municipal bonds is often, ...

in 2012 to replace the

Alaskan Way Seawall The Alaskan Way Seawall is a seawall which runs for approximately along the Elliott Bay waterfront southwest of downtown Seattle from Bay Street to S. Washington Street. The seawall is being rebuilt in the 2010s as part of a waterfront redevel ...

; the project began construction in 2013 and was completed in 2017 at a cost of $410 million, running 21 percent overbudget.

Deep-bored tunnel approved and contested

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. 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. The eight options included two surface boulevards with transit improvements, a

one-way couplet A one-way pair, one-way couple, or couplet refers to that portion of a bi-directional traffic facilitysuch as a road, bus, streetcar, or light rail linewhere its opposing flows exist as two independent and roughly parallel facilities. Descriptio ...

, 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. Several early concepts, including a bridge across

Elliott Bay Elliott Bay is a part of the Central Basin region of Puget Sound. It is in the U.S. state of Washington, extending southeastward between West Point in the north and Alki Point in the south. Seattle was founded on this body of water in the 1850s an ...

and a complete rebuild of the double-decked viaduct, were rejected by the panel of public officials. The final decision was delayed until after the

gubernatorial election A governor is an administrative leader and head of a polity or political region, ranking under the head of state and in some cases, such as governors-general, as the head of state's official representative. Depending on the type of political r ...

, but would have to meet an end-of-year deadline imposed by the state legislature. 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. 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 $ in dollars). On January 13, 2009, Governor Gregoire signed an agreement with Mayor Nickels and King County Executive

Ron Sims Ronald Cordell Sims (born July 5, 1948) is the former Deputy Secretary of the United States Department of Housing and Urban Development, having served in the position from May 8, 2009 to July 2011. He is also the former King County Executive. 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

toll Toll may refer to: Transportation * Toll (fee) a fee charged for the use of a road or waterway ** Road pricing, the modern practice of charging for road use ** Road toll (historic), the historic practice of charging for road use ** Shadow toll, ...

s. 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. In total, more than 90 alternatives were considered before the final agreement was reached in 2009. 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 Michael McGinn (born December 17, 1959) is an American lawyer and politician. He served as mayor of the city of Seattle, Washington, and is a neighborhood activist and a former State Chair of the Sierra Club. In what was characterized as a "s ...

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. 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. STP presented a $1.09 billion plan to use a

, the world's widest, to complete the tunnel by late 2015. WSDOT signed the tunnel construction contract in January 2011, sending a set of contractor agreements to the city council for approval. The state's agreements were approved by the city council in February 2011, shortly before being symbolically

veto A veto is a legal power to unilaterally stop an official action. In the most typical case, a president or monarch vetoes a bill to stop it from becoming law. In many countries, veto powers are established in the country's constitution. Veto ...

ed 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. 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. 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. The referendum was approved by 58 percent of voters on August 16, 2011, authorizing the city's agreements with WSDOT. The

Federal Highway Administration The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program a ...

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.

Tunnel boring and viaduct closure

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 launch pit to house the tunnel boring machine. Local officials, with the notable absence of Mayor Mike McGinn, participated in a ceremonial

groundbreaking Groundbreaking, also known as cutting, sod-cutting, turning the first sod, or a sod-turning ceremony, is a traditional ceremony in many cultures that celebrates the first day of construction for a building or other project. Such ceremonies are o ...

was held for the tunnel on June 20, 2012. The tunnel boring machine was manufactured by

Hitachi Zosen is a major Japanese industrial and engineering corporation. It produces waste treatment plants, industrial plants, precision machinery, industrial machinery, steel mill process equipment, steel structures, construction machinery, tunnel boring ma ...

Osaka is a designated city in the Kansai region of Honshu in Japan. It is the capital of and most populous city in Osaka Prefecture, and the third most populous city in Japan, following Special wards of Tokyo and Yokohama. With a population of 2. ...

, Japan, and named "

" in honor of Mayor

Bertha Knight Landes Bertha Ethel Knight Landes (October 19, 1868, – November 29, 1943) was the first female mayor of a major American city, serving as mayor of Seattle, Washington from 1926 to 1928. After years of civic activism, primarily with women's organiz ...

. 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. Tunnel boring was halted at near South Main Street in December 2013 after the machine encountered an unknown object that caused it to overheat. The object was found to be a steel pipe and

well casing Casing is a large diameter pipe that is assembled and inserted into a recently drilled section of a borehole. Similar to the bones of a spine protecting the spinal cord, casing is set inside the drilled borehole to protect and support the wellst ...

that was left behind by a

groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidate ...

research crew for the project in 2002. The pipe caused extensive damage to Bertha's cutterhead and main bearing seal, requiring the excavation of a rescue pit for repairs. 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. 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. During the two-year halt in tunnel boring, public officials considered alternative plans to accelerate demolition of the viaduct while awaiting tunnel completion. The project was named one of the worst

boondoggle A boondoggle is a project that is considered a waste of both time and money, yet is often continued due to extraneous policy or political motivations. Etymology "Boondoggle" was the name of the newspaper of the Roosevelt Troop of the Boy Sco ...

s in the United States by several transportation groups and critics, due in part to the stoppage and its high cost. Tunnel boring was halted by Governor

Jay Inslee Jay Robert Inslee (; born February 9, 1951) is an American politician, lawyer, and economist who has served as the 23rd governor of Washington since 2013. A member of the Democratic Party, he served as a member of the U.S. House of Representat ...

in January 2016 due to the appearance of a sinkhole in Pioneer Square, but resumed the following month. 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. Bertha completed its bore on April 4, 2017, arriving at the north portal near Aurora Avenue for disassembly, which was completed in August. The tunnel portals and their maintenance areas were completed while work on the double-decker freeway inside the tunnel progressed behind the machine. 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 The Downtown Tunnel on Interstate 264 (Virginia), Interstate 264 (I-264) and U.S. Route 460 Alternate (Chesapeake–Norfolk, Virginia), U.S. Route 460 Alternate (US 460 Alt.) crosses the Southern Branch Elizabeth River, Southern B ...

on February 4, 2019. The remaining section of the viaduct was demolished in stages between February and November 2019, with some of the of rubble deposited into the Battery Street Tunnel as it was filled and sealed. A three-block section of Aurora Avenue between Denny Way and the new tunnel portal was raised and reconnected to cross-streets in 2019. The Alaskan Way promenade and boulevard project is planned to cost $668 million and will be completed in 2024. The new boulevard will be eight lanes wide in some sections due to requirements placed by WSDOT for

Colman Dock Colman Dock, also called Pier 52, is the primary ferry terminal in Seattle, Washington, United States. The original pier is no longer in existence, but the terminal, now used by the Washington State Ferry system, is still called "Colman Dock". ...

access and the Port of Seattle for truck access. 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.

Names and designations

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 The 1990 Goodwill Games was the second edition of the international multi-sport event created by Ted Turner, which was held between July 20 and August 5, 1990. Following an inaugural edition in Moscow, the second games took place in Seattle, United ...

hosted by King County. In Seattle, the highway is known as East Marginal Way and Aurora Avenue North; in Everett, it uses Evergreen Way and Everett Mall Way. 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. The

United Daughters of the Confederacy The United Daughters of the Confederacy (UDC) is an American neo-Confederate hereditary association for female descendants of Confederate Civil War soldiers engaging in the commemoration of these ancestors, the funding of monuments to them, ...

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 The Jefferson Davis Highway, also known as the Jefferson Davis Memorial Highway, was a planned transcontinental highway in the United States in the 1910s and 1920s that began in Arlington, Virginia, and extended south and west to San Diego, Cal ...

". A pair of

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

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 The secretary of war was a member of the U.S. president's Cabinet, beginning with George Washington's administration. A similar position, called either "Secretary at War" or "Secretary of War", had been appointed to serve the Congress of the ...

. The two markers were removed in 1998 and 2002, and are now located at the privately owned Jefferson Davis Park in Ridgefield. 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. The attempted renaming, led by Snohomish representative

Hans Dunshee Hans M. Dunshee (born October 26, 1953) is an American businessman and politician of the Democratic Party. He is a former member of the Washington House of Representatives, representing the 44th Legislative District. Dunshee was born in Los Ang ...

, generated political controversy and

death threat A death threat is a threat, often made anonymously, by one person or a group of people to kill another person or group of people. These threats are often designed to intimidate victims in order to manipulate their behaviour, in which case a deat ...

s 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 African Americans (also referred to as Black Americans and Afro-Americans) are an Race and ethnicity in the United States, ethnic group consisting of Americans with partial or total ancestry from sub-Saharan Africa. The term "African American ...

Civil War A civil war or intrastate war is a war between organized groups within the same state (or country). The aim of one side may be to take control of the country or a region, to achieve independence for a region, or to change government policies ...

veteran and early settler in Snohomish. New highway signs for the William P. Stewart Memorial Highway were installed the following year, amid a new wave of Confederate monument removals.

Public transit

SR 99 is a major regional public transit corridor and carries several

bus rapid transit Bus rapid transit (BRT), also called a busway or transitway, is a bus-based public transport system designed to have much more capacity, reliability and other quality features than a conventional bus system. Typically, a BRT system includes ...

routes and a light rail line in SeaTac. The highway features

bus lane A bus lane or bus-only lane is a lane restricted to buses, often on certain days and times, and generally used to speed up public transport that would be otherwise held up by traffic congestion. The related term busway describes a roadway ...

s and business access and transit lanes (BAT lanes) in several locations to give buses traffic priority while retaining access to right turns.

Pierce Transit Pierce Transit, officially the Pierce County Public Transportation Benefit Area Corporation, is an operator of public transit in Pierce County, Washington. It operates a variety of services, including fixed-route buses, dial-a-ride transportat ...

route 500 runs on the SR 99 and Pacific Highway corridor between

Tacoma Dome Station Tacoma Dome Station is a train station and transit hub in Tacoma, Washington, United States. It is served by Amtrak trains, the S Line (Sound Transit), S Line of Sounder commuter rail, the T Line (Sound Transit), T Line of Link light ...

and

Federal Way Transit Center Federal Way Downtown is a future light rail station at the site of the Federal Way Transit Center, a bus station in Federal Way, Washington. The bus station opened in 2006 and has 1,190 parking spaces available in its parking garage and surface ...

. Through Federal Way and SeaTac, the highway is served by the

RapidRide A Line The A Line is one of six RapidRide lines (routes with some bus rapid transit features) operated by King County Metro in King County, Washington. The A Line began service on October 2, 2010, running from Tukwila to Federal Way, mostly along Pac ...

, an rapid bus route that debuted in 2010 and features enhanced bus stops and

transit signal priority Bus priority or transit signal priority (TSP) is a name for various techniques to improve service and reduce delay for mass transit vehicles at intersections (or junctions) controlled by traffic signals. TSP techniques are most commonly associat ...

Sound Transit Sound Transit (ST), officially the Central Puget Sound Regional Transit Authority, is a public transit agency serving the Seattle metropolitan area in the U.S. state of Washington. It operates the Link light rail system in Seattle and Tacoma, r ...

Link light rail Link light rail is a light rail rapid transit system serving the Seattle metropolitan area in the U.S. state of Washington. It is managed by Sound Transit in partnership with local transit providers, and consists of two non-connected lines: t ...

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. The Alaskan Way Viaduct carried several non-stop routes connecting Downtown Seattle to

West Seattle West Seattle is a conglomeration of neighborhoods in Seattle, Washington, United States. It comprises two of the thirteen districts, Delridge and Southwest, and encompasses all of Seattle west of the Duwamish River. It was incorporated as an i ...

(including the

RapidRide C Line The C Line is one of seven RapidRide lines (routes with some bus rapid transit features) operated by King County Metro in King County, Washington. The C Line began service on September 29, 2012, running between downtown Seattle, West Seattle, ...

) and Burien. Aurora Avenue is served by the

RapidRide E Line The E Line is one of seven RapidRide lines (limited-stop routes with some bus rapid transit features) operated by King County Metro in King County, Washington. The E Line began service on February 15, 2014, running between Aurora Village Transit ...

, which carried 18,000 passengers daily in 2017 and is the busiest bus route in the

King County Metro King County Metro, officially the King County Metro Transit Department and often shortened to Metro, is the public transit authority of King County, Washington, which includes the city of Seattle. It is the eighth-largest transit bus agency in t ...

system. 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. The E Line terminates in Downtown Seattle and near the county line at the Aurora Village Transit Center, where

Community Transit Community Transit (CT) is the public transit authority of Snohomish County, Washington, United States, excluding the city of Everett, in the Seattle metropolitan area. It operates local bus, paratransit and vanpool service within Snohomish Cou ...

's route 101 and

Swift Blue Line The ''Swift'' Blue Line is a bus rapid transit route operated by Community Transit in Snohomish County, Washington, as part of the Swift system. The Blue Line is long and runs on the State Route 99 and Evergreen Way corridor between Everett Sta ...

begins. Swift features off-board fare payment and longer spacing between stops, and runs from Shoreline to

Everett Station Everett Station is an Amtrak train station serving the city of Everett, Washington. The station has provided service to the '' Cascades'' and ''Empire Builder'' routes since its opening in 2002, replacing an earlier station near the Port of E ...

via Evergreen Way. The Everett Mall Way section of SR 99 is served by

Everett Transit Everett Transit is the public transit authority of Everett, Washington, the only city in Snohomish County not to belong to Community Transit. As of 2017, Everett Transit operates 42 buses within Everett on ten routes. Its annual ridership in 2016 ...

route 7, which connects the Everett Mall to Downtown Everett and Everett Station.

Major intersections

References

External links

*
Highways of Washington StateSR 99 Alaskan Way Viaduct Replacement Program
{{DEFAULTSORT:Washington State Route 099 099 Transportation in Pierce County, Washington Transportation in King County, Washington Transportation in Snohomish County, Washington Seattle metropolitan area U.S. Route 99