OLYMPIA – WSDOT awarded a $31.0 million contract this week to Bellevue-based Tri-State Construction, Inc. to extend the Interstate 5 HOV network south from King County. This two-year project adds carpool lanes on northbound and southbound I-5 from the King County line to the Port of Tacoma Road interchange in Fife, about three miles in each direction. Work begins later this summer.