One more advance traffic alert – this one two weeks away, involving the so-called Timber Bridge project on Highway 99 south of the West Seattle Bridge. We first told you about this impending work back in November, and more recently shared WSDOT’s announcement that work would begin on February 25th. We now have details on a weekend closure immediately preceding that, to reorganize traffic on the structure to make way for the crews, and to move underground utility pipes out of the way, as described by WSDOT’s Broch Bender, followed by details of the changes that then will be in effect during the project:

During the weekend of Feb. 22-25, the project will relocate a waterline under the existing timber structure and shift traffic to the west half of the bridge (where the southbound lanes are today). All traffic on SR 99 over S. Spokane Street will be shifted to the west to allow crews room to safely demolish the timber overpass and replace it with a new, concrete supported structure.

Closure details:

· 10 pm Friday, Feb. 22 to 5 am Monday, Feb. 25 – Both directions of SR 99 between the West Seattle Bridge and S. Nevada Street will be closed around the clock.

o Southbound SR 99 will be closed from the Battery Street Tunnel to S. Nevada Street, traffic will be detoured off the highway at Denny Way.
o Northbound SR 99 will be off-limits to drivers between S. Nevada Street and the West Seattle Bridge. South of Diagonal Street, traffic will be detoured to First Avenue S. North of Diagonal Street, signs will direct drivers off of SR 99 at the West Seattle/S. Spokane St./East Marginal Way S. exit.

Then on Monday, February 25th, after the closures, here’s how the traffic flow will work:

·Southbound traffic: South of the West Seattle/Harbor Island exit, southbound traffic will be reduced to one lane between the West Seattle Bridge and S. Nevada Street.

Northbound traffic: Two lanes of northbound traffic between S. Nevada Street and the West Seattle Bridge will be shifted to the west. The third lane remains the drop-lane for the northbound exit to West Seattle and East Marginal Way S.
· Slower speeds: A temporary speed limit reduction to 40 MPH in both directions of SR 99 will be extended south of the Alaskan Way Viaduct through the construction zone to approximately S. Idaho Street.

A map showing all that – as requested at the South Portal Working Group meeting earlier this week – should be available by tonight, and we’ll add it to the story when it is. The project is expected to last into June of next year, as crews demolish and rebuild the overpass one half at a time; once the east half is complete, it’ll handle traffic so work can commence on the west half.