Commuters heading to Tacoma from Auburn on Tuesday will see dramatic changes in the highway construction spectacle at Federal Way.
Construction crews working over the weekend filled in the remaining gaps in the massive flyover ramp that, when it opens this summer, will lift westbound state Route 18 traffic over Interstate 5 and ease it onto southbound freeway lanes a half-mile away.
The $113 million project has been in the works since August 2010, but until Saturday morning the arc of the sky bridge existed only on paper.
Nighttime operations to install steel bridge girders over the freeway required an overnight shutdown of southbound lanes of I-5 on Feb. 10 and a shutdown of northbound lanes Friday night. The girders will support the roadway for the flyover ramp.
During a third and final freeway closure next weekend, crews will install more girders to complete a separate flyover that will connect traffic heading to Seattle from Federal Way.
Southbound lanes will close Friday night; northbound lanes will close Saturday night.
Construction is proceeding on time and within budget, said Aleta Borschowa, the state Department of Transportation’s project engineer.
“We’re actually several months ahead of schedule,” Borschowa said Friday.
The Federal Way project is being funded almost entirely with gas taxes passed by the Legislature in 2003 and 2005. The federal government is contributing about $9 million of the $113 million cost.
Changes that are now visible are just the beginning of what is planned for the notoriously congested and dangerous intersection.
The current phase of the project replaces two of four cloverleaf ramps. Future projects – which currently are not funded but which the Transportation Department estimates will cost $215 million to $235 million – call for five new ramps and additional lane expansions.
The existing cloverleaf intersection at Federal Way opened in 1962, when Seattle built the Space Needle and hosted the World’s Fair. At the time, the cloverleaf interchange was the state of the art in freeway design.
In the following decades, growth exploded in South King County, caused in part by the efficiency of the freeway.
Traffic volume quadrupled, pushing the cloverleaf interchange beyond its limits and turning the loop ramps into a nexus for side-swipe collisions as drivers jockeyed for position as they tried to enter and exit the freeway.
Rob Carson: 253-597-8693
rob.carson@thenewstribune.com
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