I-90 Hyak Snoqualmie Pass, Washington
SDA was the maintenance traffic lead for a 3-mile portion of the I-90 corridor adjacent to Keechelus Lake east of Hyak. The role required management, oversight and design for 10 construction stages. Each stage required roadway design plans including horizontal control, profiles, sections and channelization plans to maintain the continuous operation of 2 travel lanes in each direction during construction.
This project built new multi-level, “braided” ramps to separate vehicles entering and exiting northbound I-405 between NE 8th Street and SR 520 in Bellevue. The project also adds a bypass lane for I-405 traffic heading eastbound to SR 520. A new ramp from the NE 10th Street overpass will give drivers direct access to SR 520 from downtown Bellevue.