SR 9/SR 92 Intersection Improvements
Atkinson reduced congestion and improved traffic operations at the SR 9/SR 92 intersection by widening the roadway. The widening accommodated the construction of one additional southbound through lane on SR 9, a second southbound left turn lane on SR 9, and extension to the northbound right turn lane on SR 9, a second eastbound lane on SR 92 to Lake View Drive, and a second westbound left turn lane on SR 92. Work included grading, drainage, permanent signing, illumination, signals, pavement markings, retaining walls, water quality facilities, guardrail installation, temporary erosion and sediment control, and traffic control.
We designed and constructed the intersection to account for the City of Marysville Master Plan. The SR 92 widening and placement of signals and sidewalks allowed for a future fourth leg of the intersection—extending west into Marysville—without requiring demolition or reconstruction.
When WSDOT was unable to acquire a needed Seattle City Light property for a dispersion trench, our design team proposed installing three Filterra units to reduce the needed surface area for dispersion. Our teams increased the pond size to account for the additional flow control.
Atkinson committed to beating the RFP deadline—opening all lanes to traffic within four months (August 31, 2012 vs. December 31, 2012). However, innovation allowed us to beat our own goal by 11 days—opening traffic in its final configuration on August 20, 2012. This innovation included construction staging and maintenance of traffic (MOT) plans to perform most of the work behind concrete barrier and to complete final paving, striping, and signal installation during a weekend closure. Our MOT configurations maintained continuous access to nearby businesses and residences and required no lane alignment shifts, deviations, or reductions from the normally posted speed limit—allowing drivers to maintain their routine and ensuring safety by eliminating interface between construction activities and drivers.