Crews start traffic revision preps to tear down Seattle viaduct

Crews are prepping Alaskan Way for the next big revision for the Seattle tunnel project -- which will allow demolition crews to take down the viaduct.

Traffic signal poles, trenching and underground conduits as well as cables and overhead traffic signals are getting installed on the roadway just to the west of the viaduct.

When it's done, car and truck traffic will move over, making way for crews to demolish the viaduct after the new tunnel opens to traffic.

Years ago, traffic was moved under the viaduct for construction of the seawall project.

Some parking spaces and parts of intersections will temporarily close while the construction is going on.

When it's all finished, traffic will run between the viaduct and the piers on the waterfront.

The switch will happen just before the viaduct is closed for three weeks so traffic on SR 99 can be diverted from the viaduct to the new tunnel, probably sometime this fall.

The Washington State Department of Transportation said the work will not disrupt the new, free Waterfront Shuttle which runs through the area every 25 minutes.