Going to West Seattle late tonight? It will be a bit more complicated than usual. The Seattle Department of Transportation is closing the westbound lanes of the Spokane Street Viaduct between I-5 and SR99 from 10 p.m. tonight, Thursday, October 20, until 5 a.m. tomorrow morning, October 21, to test techniques for preparing old deck for new paving.

Traffic from Beacon Hill via Columbian Way will be detoured onto 6th Avenue South to a route leading to the lower-level Spokane Street swing bridge.

See more about the Spokane Street project here.

Also take note that October 21 at 7:30 p.m. is the beginning of the nine-day closure of the Alaskan Way Viaduct, which is likely to cause congestion in Sodo and downtown. See the Washington Department of Transportation website for more information about the closure and alternative routes.

We were curious about the exact process going on with the Viaduct replacement project, and found this interactive project simulation on the WSDOT website that explains it visually.