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The breakthrough of Bertha is a critical part of the changing face of South Lake Union.

The city is planning to reopen three east-west thoroughfares in the area that, in theory, will help alleviate traffic congestion.

Since World War II era, east-west roads like John Street, Thomas Street, and Harrison Street were all cut off by the jersey barrier of Highway 99.

Seattle Department of Transportation workers can now prepare to reopen those roads, because of the lid that will lay over the tunnel’s north portal.

“We will go through two cross streets, east-west streets, in that area to five. That's really exciting to think about,” said Mark Bandy, SDOT’s transportation operations director.

Mercer Avenue and Denny Way are the only two east-west streets in that area that cross Highway 99.

According to WSDOT, Harrison Street will reopen over Highway 99 when the tunnel reopens; Thomas Street and John Street will open shortly thereafter, likely in 2019.

That will give cars and pedestrians three new roads to connect from lower Queen Anne to South Lake Union.

“I don't think a lot of people realize how close it is from the South Lake Union neighborhood to Seattle Center. It's just seven blocks; it feels much longer because you have to walk up to Mercer or down to Denny. From a walking perspective it will be a nice change,” said Bandy.

As the tunnel will give commuter options, it will also take away. SDOT reminds drivers that the Seneca and Battery Street exits from the viaduct will no longer exist with the tunnel to access downtown.