Wondering what’s going on inside the SR 99 tunnel now that Bertha is no longer there? The Washington State Dept of Transportation  has posted a drone fly through video shot in late September that takes a trip from the tunnel’s north end, near the Space Needle, all the way out the south end, near the stadiums. You can see two miles of ongoing construction work in just two minutes.

The work advances from the south, so as the drone moves south, you see a more completed tunnel. The corbels (foundations of the road and walls) are 100% complete, the top deck of the double deck road is more than 85% complete. You can follow construction progress here, on a page that’s updated monthly. Click on the small circles of the graphic for a more interactive illustration.

Next month, Seattle Tunnel Partners expects to start bringing in prefabricated road panels (made in Tacoma) that will be assembled to create the lower roadway. There’s a section in the video that graphically illustrates where the lower roadway will go.