Viaduct Beginnings

Journey back in time to learn about the structure’s past.


By the 1920s, Seattle's waterfront street (Railroad Avenue) was heavily congested with trains, trucks and wagons carrying cargo to and from ships. It wasn't actually a street at all, but a deteriorated 150-foot-wide timber trestle. It was not until 1934 that a seawall was extended to Broad Street at the north end, allowing the roadway to be filled and paved. The new street, now known as Alaskan Way, was completed in 1936. The improvement attracted more trucks, automobiles and greater congestion.

Planning for the Alaskan Way Viaduct began in the early 1930s, primarily to relieve this congestion. Planners also wanted to provide a direct route through downtown and connect to Aurora Avenue on the north end of downtown. The George Washington Memorial Bridge (known also as the Aurora bridge) opened in 1932, bringing traffic down Aurora Avenue to Denny Way at the edge of downtown. However, the Depression and World War II delayed further work on the waterfront highway project.

Transportation planning resumed after the war. A 1947 traffic study showed that the best way to meet the city's traffic needs at that time would be to construct two new north-south routes: an elevated highway along the waterfront and another highway just east of downtown (built in the 1960s as I-5). The Alaskan Way route was built first because it was less costly, as the city already owned most of the property where the two level viaduct would be placed.

To learn more, read these essays at

October 1947
Study prioritizing north-south routes completed


May 1948
First segment planning completed

Crews drilling test holes for the Alaskan Way Viaduct, 1948
Alaskan Way Viaduct under construction, 1952. Photo courtesy of Seattle Municipal Archives No. 42972
Alaskan Way Viaduct under construction, 1951. Photo courtesy of Seattle Municipal Archives No. 42972

Click thumbnail for larger view.

Photos courtesy of the Seattle Municipal Archives


By 1949 the design was finalized and the initial funding (a combination of city, state and federal contributions) was assured. Construction was completed in phases to minimize disruption and to secure funding for each section. The first phase, from Battery Street to Pike Street below the Pike Place Market, was the most difficult, and was built between December 1949 and July 1951. Even before this was completed, construction began on the second section, from Pike Street to King Street, and finished in August 1952. The third section began in November 1951, but was not completed until April 1953 because of a nationwide steel strike. These three sections, extending from Battery Street to Railroad Way/S. Dearborn Street, were opened to traffic on April 4, 1953, three and a half years after construction began. The two ramps at the south end near Railroad Way S. served as the southern terminus of the project until the connection to S. Spokane Street was completed in 1960.

The Battery Street Tunnel was the vital "missing link" to connect the new waterfront structure with Aurora Avenue / SR 99. The tunnel was dug beneath Battery Street, with minimal disruption to surrounding buildings. Work started in September 1952 and it opened to traffic in a grand ceremony on July 24, 1954. Planning of the tunnel was a long process, with extensive discussion of key features such as the ventilation and fire protection systems. The automatic deluge sprinkler system was believed to be the first such system installed in a vehicular tunnel. Learn more in the Alaskan Way Viaduct and Battery Street Tunnel Historic American Engineering Record report (pdf 483 kb.)

To learn more, read these essays at

April 1953
S. King Street to Railroad Way S./First Avenue S. completed
April 4, 1953
Section between Battery Street and Railroad Way S./First Avenue S. opened

July 1951
First segment (Battery Street to Pike Street) completed


August 1959
Railroad Way S. to S. Holgate Street completed
September 3, 1959
Entire viaduct opened, from Aurora Avenue to S. Holgate Street to SR 99 to the south


August 1952
Pike Street to S. King Street completed

Alaskan Way Viaduct under construction, 1950
Test piles for Alaskan Way Viaduct at Marion Street, 1948
Viaduct construction behind Pike Place Market, 1950

Click thumbnail for larger view.

Photos courtesy of the Seattle Municipal Archives


Extending the viaduct to S. Holgate Street, where Alaskan Way ran into E. Marginal Way S., was intended from the beginning, but was delayed because of a lack of financing. This operation was completed in two phases between June 1956 and August 1959. The design, property acquisition and construction were particularly challenging because of the five nearby railroads with extensive trackage and numerous warehouses. Later contracts improved the roadway from S. Holgate Street to S. Dakota Street, south of the Spokane Street Viaduct.

By 1959 traffic congestion and the demand for better downtown access led City officials to seriously consider constructing downtown ramps. Ramp construction had also been intended from the beginning, but the number, location and funding sources were uncertain. The Seneca Street off-ramp was built first, to provide access from the south. Work began in May 1961 and was completed in October 1961, despite the constricted space and foundation problems. The Columbia Street on-ramp was completed on February 1, 1966.

The viaduct proved to be a popular and effective transportation route. Since its opening in 1953, traffic has steadily increased. Even though the I-5 freeway is now the primary north-south route, the viaduct, anticipated to carry 60,000 vehicles a day, now carries approximately 110,000 vehicles a day, or 20 to 25 percent of the traffic through downtown Seattle. It is crucial to transit and freight operations, serving the Duwamish and Ballard-Interbay industrial areas and the Port of Seattle.

To learn more, read this essay at

October 1961
Seneca Street off-ramp completed


February 1966
Columbia Street on-ramp completed

Carbon monoxide test in tunnel, 1954
Battery Street Tunnel construction, 1953

Click thumbnail for larger view.

Photos courtesy of the Seattle Municipal Archives


However, within a decade of its completion, calls began for its demolition. Shipping had moved south of the central waterfront. In the 1970s the City enhanced the waterfront with a public park and aquarium near the foot of Pike Street. Piersheds and nearby buildings were converted to restaurants, offices, condominiums and tourist attractions. Major restorations took place in Pioneer Square, along Western Avenue and at the Pike Place Market, including a new connection between the waterfront and the market, the city's most popular tourist attraction. A waterfront trolley and adjacent bike trail and landscaping were added. The Port transformed the northern waterfront, near Bell Street, by adapting a large piershed into its headquarters and building a marina and conference center, with a hotel, offices and condominiums on the upland side. People coming to the waterfront for enjoyment and those who live or work nearby came to see the viaduct's noise and massive concrete presence as a barrier to enjoyment and economic development of the waterfront--leading to discussions of numerous alternatives.

Years of daily wear-and-tear have taken their toll on the Alaskan Way Viaduct. The 2001 Nisqually earthquake damaged the viaduct and caused it to settle into the weak fill soil underneath. Learn more about plans to replace the aging Alaskan Way Viaduct.

To learn more, read these essays at

Railroad Way end, before operation to S. Holgate Street, 1953
Seneca Street ramp, 1961

Click thumbnail for larger view.

Photos courtesy of the Seattle Municipal Archives

{Alaskan Way Viaduct Trivia}

Ahead of its time:

  • First double-deck bridge in Washington
  • First tunnel designed by the City of Seattle Engineering Department
  • First direct connection between downtown Seattle and industrial areas to the south
  • First forced-air ventilation system in a tunnel

Carrying the load:

  • Number of cars carried daily on Alaskan Way before the construction of the Alaskan Way Viaduct: 40,100
  • Number of cars the new structure was designed to carry daily: 60,000
  • Number of cars the structure currently carries daily: 110,000

Throughout the years:

  • An elevated waterfront freeway was first discussed: 1920s
  • Construction started: 1950
  • Construction of mainline completed: 1953
  • Construction of Battery Street Tunnel completed: 1954
  • Operations from S. Holgate Street to S. Spokane Street completed: 1959
  • Downtown ramps completed: 1966

Featured dignitaries at the 1952 ceremonial opening of the mainline:

  • Mayor Allen Pomeroy
  • Director of Highways William Bugge
  • Automomobile Club of Washington President D.K. McDonald
  • Seafair Queen Iris Adams

Did you know?

  • Cubic yards of soil removed for the Battery Street Tunnel: Approximately 100,000
  • Gallons of gasoline spilled in a tanker accident in 1975: 3,700
  • Number of hours downtown Seattle was without power after the resulting fire: 36

{Photo Gallery}

The Historic American Engineering Record (HAER) is a National Park Service (NPS) program that documents historic engineering. It was jointly founded in 1969 by NPS and the American Society of Civil Engineers to record historically important national engineering accomplishments. The Alaskan Way Viaduct Program and NPS worked together to create a HAER record (pdf 483kb) for the Alaskan Way Viaduct. The record consists of a narrative description and a series of photos which include the pictures below. The large format HAER photographs were taken by renowned National Park Service photographer Jet Lowe in 2009.

Click on a thumbnail for larger view.

Railroad tracks at south end of Alaskan Way Viaduct
Aerial view of Battery Street Tunnel northbound entrance
Aerial view of Alaskan Way Viaduct facing south
Aerial view of Battery Street Tunnel southbound entrance
Aerial of Alaskan Way Viaduct on central waterfront
Aerial of Alaskan Way Viaduct looking north
Beginning of Alaskan Way Viaduct on south end
Double-decker section on south end of Alaskan Way Viaduct
Looking south at the southbound ramp and flying buttresses where the Alaskan Way Viaduct returns to street level
Underside of Alaskan Way Viaduct showing First Avenue S. ramps
“Dearborn St.” Sign
Sign bridge south of Battery Street Tunnel
Section of concrete rail
Detail of the notch in the Alaskan Way Viaduct where the corner of the Empire Laundry Building was incorporated into the structure
Battery Street Tunnel controls
Alaskan Way Viaduct from Pioneer Square

View the Alaskan Way Viaduct Replacement Program's Flickr collection.

About us

This site is dedicated to the history of Seattle's downtown and waterfront, especially the State Route 99 / Alaskan Way Viaduct corridor. It was developed by the Washington State Department of Transportation and the Federal Highway Administration as an educational resource and as part of a Memorandum of Agreement for Section 106 of the National Historic Preservation Act (pdf 1mb).

Copyright 2011 Washington State Department of Transportation