HWA conducted a geotechnical & pavement engineering investigation for SDOT’s proposed improvements along Harrison and Mercer streets in Seattle, WA. Improvements include transit speed and reliability treatments as well as the design of bus lanes, channelization and signal optimization for buses, transit signal priority, and bus stop location/consolidation. HWA performed pavement coring and Falling Weight Deflectometer testing to measure pavement deflections and subgrade conditions.

HWA was the lead geotechnical engineer for the Federal Way City Center Access – Phase 1 Project. The project included multi-modal improvements near I-5 and the S 320th St interchange. Key elements were extending and widening S 324th St, modifying on/off ramps, adding a multi-use trail, converting lanes to HOV, and replacing existing culverts with fish-passable culverts.

East Marginal Way provides access to the Port of Seattle terminals, rail yards, industrial businesses, the regional highway system, between MIC's, and provides a major connection for bicyclists as well. HWA’s services included conducting a site investigation program, performing geotechnical engineering analyses, and providing recommendations for design including infiltration capacity, potential for liquefaction, luminaire and signal poles and railroad track relocation.