The Washington State Dept. of Transportation has extended completion of the $1-billion Highway 99 bored tunnel under Seattle to November 2016. Three international teams are vying to build the 56-ft-wide tunnel that will replace the Alaskan Way Viaduct. WsDOT will offer technical credits for proposals that set a completion date earlier than 2016. The project will require the world’s largest-diameter boring machine, with drilling to take 13 months.
Seattle Megaproject Timeline Extended By A Year
June 2, 2010