SEATTLE Drivers who use State Route 99, including the Alaskan Way Viaduct, to get through Seattle need to plan for five days of closures starting next Friday. It s the latest part of the project to replace the viaduct with a tunnel.

The Broad Street Bridge is being demolished because it s now in the wrong place.

Starting at 10 p.m. on Friday, Aug. 22, through the following Monday at 5 a.m., Highway 99 will be shut down from Spokane street south of downtown to Valley Street in the South Lake union neighborhood.

Yes, there is a Seahawks preseason game that Friday night. Part of the northbound lanes will be left open for a few more hours to help fans get out.

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On that Monday and Tuesday, the viaduct will be re-opened as far north as Western Avenue, but 99 will remain closed through the Battery Street tunnel to Valley Street until 5 a.m. Wednesday.

If there s a bad accident on Interstate 5 during all this, brace yourself.

If you can't use north or southbound 99, you re going to see surface street gridlock, said KING 5 Traffic Reporter Tracy Taylor. People are going to exit off of I-5 and they're going to try and find their way around. We're going to see absolute gridlock downtown if we're not prepared for that.

So you may want to make that a long weekend, work from home or leave for work early.

KING 5's Glenn Farley contributed to this report

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