SR 519 / Alaska Way Viaduct Phase II Alternatives and Port Access Study

SR519 Port access study






Seattle, WA

Transpo assisted the Alaskan Way Viaduct and Seawall Replacement project team with the SR 519 Alternatives Development, Analysis, Preliminary Design and Environmental Documentation. The analysis identified ways to improve freight mobility and traffic between I-90 and the Alaskan Way Viaduct.

The project addressed the needs of multiple stakeholders including the two stadiums, the Port of Seattle, Sound Transit, Burlington Northern Santa Fe Railroad, as well as the SODO district’s future plans. Stakeholders were concerned that Phase II would create a freeway off-ramp environment opposed to a “stadium district” atmosphere. Transpo created a four-step travel demand model to develop multiple horizon year system-wide volumes. Design alternatives considered vehicular and freight traffic, connectivity with the container port, multiple logistics and rail, roadway, intersection and interchange configurations. Transpo was instrumental in developing the preferred solution, and participated in its conceptual and preliminary design.