I-405/SR 167 Interchange HOV Direct Connector
Atkinson constructed a direct connector flyover bridge to join the northbound and southbound SR 167 high occupancy toll (HOT) lanes with the I-405 high occupancy vehicle (HOV) lanes by reconstructing portions of SR 167 and I-405 to accommodate the new direct connector ramps in the median. The scope of work also included two new I-405 bridges over SR 515 and installing a fish passable Rolling Hills Creek culvert under SR 167.
Atkinson and Jacobs optimized the interchange design to reduce the roadway footprint width by 50 feet and—subsequently—the quantity of excavation from Talbot Hill by 100,000 cubic yards. In combination, our nine approved Alternate Technical Concepts (ATCs) allowed us to build the majority of the project offline—away from traffic—reducing impacts to adjacent businesses, residences, and wetlands. This significantly assisted the Atkinson team to achieve the goal of maintaining current traffic capacity throughout construction on one of the highest volume interchanges in Washington.
The project team moved the existing 1,400 LF noise wall up the hill to a new location—using 116 of the existing panels. To minimize impacts to the Talbot Hill neighborhood, we committed to complete this work in four months and significantly beat our proposed schedule—moving the noise wall in just six weeks. In addition, work included rehabilitating PCCP pavement panels and HMA pavement, retaining walls, stormwater treatment and detention facilities, utilities, signing, pavement markings, illumination, intelligent transportation systems (ITS), and Toll Infrastructure components.