The Alaskan Way Viaduct – a major thoroughfare for commuters along downtown Seattle’s waterfront – shuts down for good Friday, bringing anticipated traffic strain and pain.

The double-decker viaduct, which supports about 90,000 vehicles each day, will be replaced by a new four-lane tunnel. But the bored-road SR 99 Tunnel won’t open until about three weeks after the viaduct closes as workers realign the highway into it.

Stay tuned.