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A: Demand management and low capital
This scenario combines lower cost investments in new roads or transit service with a maximum effort to manage transportation demand.
Alaskan Way would be two-lanes in each direction north of Yesler Way, with bike lanes and parking. There would be signalized intersections on the waterfront. This scenario would also reconnect the east/west street grid north of the Battery Street Tunnel with new signalized intersections on Aurora Avenue.
Transit lanes would be added on several downtown streets, including Second and Fourth avenues where there would be an increase from four to five lanes. New or enhanced bus rapid transit lines would be introduced in Delridge, Lake City Way, Ballard, West Seattle and on Aurora Avenue. North and southbound improvements to I-5 are also included.
This scenario would offer open space along the central waterfront of approximately 52-86 feet. |
Central waterfront cross section
The Scenario A map (pdf 4.2 mb) shows all of the components included in this scenario.
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B: Surface boulevard and transit
Scenario B is similar to Scenario A, but it has more capital investments and more aggressive transit improvements.
Alaskan Way would be two-lanes in each direction north of Yesler Way, with bike lanes and parking. There would be signalized intersections along the waterfront. The east/west streets north of the Battery Street Tunnel would be reconnected with new signalized intersections on Aurora Avenue.
In this scenario the streetcar system would be extended, with lines to Fremont/Ballard, University District, central downtown, and Capitol Hill/First Hill. The bus rapid transit system would be extended with lines for Delridge and Lake City Way and from Ballard to the University District. This service would be in addition to planned new lines serving Ballard, West Seattle and Aurora Avenue.
There would also be more extensive I-5 improvements than with Scenario A. An additional northbound lane on I-5 would start near Cherry Street and go north to SR 520.
This scenario would offer open space of 76-86 feet along the waterfront. |
Central waterfront cross section
The Scenario B map (pdf 4.2 mb) shows all of the components included in this scenario.
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C: Alaskan Way and Western Avenue one-way couplet
Scenario C would create a pair of north and southbound one-way streets, called a couplet, along the waterfront.
Western Avenue would become a one-way northbound street with three lanes and a bike lane. Alaskan Way would become a one-way southbound street with three lanes and a bike lane. Northbound Western Avenue would start near Yesler Way and connect back to Alaskan Way just south of Pike Place Market.
The street grid north of the Battery Street Tunnel would be reconnected with signalized intersections on Aurora Avenue. I-5 and transit improvements would be similar to Scenario B, except this scenario does not include streetcar extensions to Ballard, Fremont and University District.
This scenario would offer open space of 80-114 feet along the waterfront. |
Central waterfront cross section
The Scenario C map (pdf 1.2 mb) shows all of the components included in this scenario.
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D: Four-lane elevated
This scenario pairs four elevated lanes on the waterfront with a lower level of surface, transit, demand management, and I-5 improvements.
SR 99 would run along the waterfront on two independent bridge structures, side-by-side, with two lanes in each direction.
Access to downtown from SR 99 would be provided in the south by a King Street/Railroad Way off-ramp and in the north at Elliott Avenue/Western Avenue – there would be no access at Columbia Street or Seneca Street.
Efforts to reconnect the street grid north of the Battery Street Tunnel would include a new Republican Street underpass. Some downtown streets would gain transit lanes; otherwise, transit improvements would be modest.
This scenario would have I-5 improvements both north and southbound and would offer open space of 20-70 feet along the waterfront. |
Central waterfront cross section
The Scenario D map (pdf 1.2 mb) shows all of the components included in this scenario.
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E: Four-lane integrated elevated
This scenario pairs four bypass lanes on the waterfront with a lower level of surface, transit, demand management, and I-5 improvements.
The integrated elevated structure would have one level of enclosed traffic with two lanes in each direction. The upper deck would be an open park, and development would be allowed underneath the roadway. The development could be offices, retail or housing.
Alaskan Way would have two southbound lanes, and Western Avenue would have two northbound lanes from Washington Street to Union Street.
East/west traffic access to Alaskan Way would be provided through openings under the integrated elevated structure. Sky-bridges could connect the buildings on the east side of the structure to the park.
Efforts to reconnect the street grid north of the Battery Street Tunnel would include a new Republican Street underpass. Some downtown streets would gain transit lanes; otherwise, transit improvements would be modest.
This scenario includes improvements only to northbound I-5.
Open space on the central waterfront would be 45-135 feet. |
Central waterfront cross section
The Scenario E map (pdf 857 kb) shows all of the components included in this scenario.
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F: Four-lane bored tunnel
This scenario pairs four bypass lanes in two bored tunnels with a lower level of surface street, transit, demand management, and I-5 improvements.
The tunnels would have two lanes in each direction. They would extend from approximately Royal Brougham Way to Harrison Street.
This scenario also includes a pair of north and southbound one-way streets, called a couplet, using Alaskan Way and Western Avenue and northbound-only I-5 improvements. Some downtown streets would gain transit lanes; otherwise, transit improvements would be modest.
Open space on the waterfront would be approximately 80-114 feet. |
Central waterfront cross section
The Scenario F map (pdf 1.9 mb) shows all of the components included in this scenario.
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G: Four-lane cut-and-cover tunnel
This scenario pairs four bypass lanes on the waterfront in a cut-and-cover tunnel with a lower level of surface street, transit, demand management, and I-5 improvements.
The cut-and-cover tunnel would be side-by-side with two lanes in each direction. Alaskan Way would be a four lane boulevard with two lanes in each direction.
This scenario includes a widened Mercer Street underpass and a new Republican Street underpass to reconnect the street grid north of the Battery Street Tunnel. It also includes additional transit lanes on some downtown streets and northbound and southbound I-5 improvements.
Open space on the waterfront would be approximately 52-80 feet. |
Central waterfront cross section
The Scenario G map (pdf 1.3 mb) shows all of the components included in this scenario.
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H: Depressed/lidded roadway
This scenario pairs four bypass lanes on the waterfront in a lidded trench tunnel with a lower level of surface street, transit, demand management, and I-5 improvements.
The four-lane lidded trench concept is a tunnel that is not fully enclosed. It would have two lanes in each direction in a side-by-side trench with openings roughly every 300 feet between Union Street and Yesler Way. The openings would allow for natural ventilation, and the lidded portions would provide pedestrian connections and east/west connections to surface Alaskan Way.
North of Union Street and south of Yesler Way, this scenario is similar to a surface street scenario. Street grid improvements would include signalized intersections north of the Battery Street Tunnel and south of Yesler Way. Transit lanes would be added on some downtown streets. This scenario also includes improvements to north and southbound I-5.
Open space on the waterfront would be 40-80 feet. |
Central waterfront cross section
The Scenario H map (pdf 1.3 mb) shows all of the components included in this scenario.
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