Keeping Seattle Moving: Developing a Multimodal Transportation Management Process for Maintaining Mobility During Construction of the Alaskan Way Viaduct Seawall Replacement Project

摘要

The Alaskan Way Viaduct and Seawall Replacement Project (the Project), is arncomprehensive effort to replace a 1950’s era viaduct (SR 99), which was severelyrndamaged in the 2001 Nisqually earthquake, with a new facility built to current roadwayrnstandards. While the process to identify a preferred alternative moves forward, it isrnexpected that any alternative would require extended periods of roadway closure in therncorridor to accommodate an accelerated construction schedule and deal with natural andrnbuilt environment constraints.rnSR 99 is a primary north-south route through Seattle, carrying 20 to 25 percent of therntraffic traveling through downtown. Currently, the facility carries about 110,000 vehiclesrntrips per day, with daily volumes projected to increase to over 130,000 by 2030. It isrnanticipated that without any additional improvements during extended periods ofrnroadway closure, north-south downtown arterial streets and Interstate 5 will bear thernbrunt of diverted SR 99 traffic, causing significant increases in delay for general purposerntraffic, transit vehicles and freight.rnTo address the anticipated increase in traffic, a construction transportation managementrnplanning process has been established. The process will provide agencies, stakeholdersrnand the public a general picture of what traffic will be like during various stages ofrnproject construction. It will identify strategies that will be implemented during variousrnphases of project construction phases to move people and goods around as effectively asrnpossible.rnThis paper will discuss the reasons for developing the process, its elements,rnmethodology, recommendations, and how it is being received by the transportationrncommunity in the greater Seattle area.