Future of the Gardiner Expressway - Nanos Research

The Governor announced in early 2009that the viaduct will be replaced by deepbored tunnel under downtown Seattle. Thisalternative was not evaluated in the EIS. Costfor the bored tunnel is estimated at US $4.24billion.Urban DesignThe Alaskan Way Viaduct, in particularbecause it is a double-decker structure,is thought to reduce the quality of thedowntown environment and potential portareadevelopment value. Its visual impact onSteinbreuk Park is especially felt, since thisopen space is symbolically important to bothdowntown and the city.Most land in the downtown waterfront areais privately-owned. While some developmentparcels will be created, the City of Seattledoes not stand to significantly re-capturepublic investment value through landdisposition. Direct economic benefits to theCity would come through increased tourismand rising property values.The viaduct also poses a sharp environmentalchallenge to Seattle – maintaining currenttraffic volumes on the viaduct will likelyexceed state carbon reduction goals, some ofthe most ambitious in the U.S.The study’s urban design objectives weremostly related to existing waterfront land useplans. Pedestrian and bicycle access werekey goals, as well enhanced waterfront andmountain views. All alternatives studied howto create waterfront pedestrian realm andwhether bringing the viaduct to grade might,in fact, diminish existing pedestrian realm.The viaduct is an aging infrastructure. For thisreason, safety and design deficiencies – forexample, 3-meter-wide (10 feet) lanes – werekey concerns. Yet transportation strategiesrevolved around a key question. Shouldviaduct redesign accommodate existing trafficvolumes – 110,000 vehicles per day – orencourage mode shift?Existing condition under the Viaduct.Rendering of proposed condition.Alaskan Way Viaduct Section – After (Proposed)SECTION V: Case studies 21