I-5 SR 510 Diverging Diamond Stormwater Drainage
Osborn Consulting was the drainage and TESC lead providing design engineering, plans, specifications, and estimates (PS&E) for WSDOT’s first diverging diamond interchange (DDI) project, located in Lacey WA. In addition to constructing a DDI at the I-5/SR 510 interchange, this project widened the existing SR 510 bridge structure to accommodate the new DDI interchange footprint, including bike lanes and sidewalk, a modified the SB on-ramp, and added a Collector-Distributor (CD) Road and Frontage Road adjacent to the I-5 SB lanes.
Drainage & TESC Lead
As a result of this project, the rebuilt interchange has helped ease congestion during periods of heavy traffic while also mitigating the possibility of crashes. With the addition of improved ease of use for pedestrians and bicyclists, Washington’s first DDI has been instrumental in improving traffic flow.