[1] The east portals of the tunnel, with murals titled Portal of the North Pacific designed by artist James FitzGerald, along with the Lacey V. Murrow Bridge, are an official City of Seattle landmark.

The former west portal, now located well inside the tunnel, is no longer discernible and its two arch structures were removed during 1989–1993 modification work.

[4][5][6] When completed in 1940, the twin tunnels connected the I-90 floating bridge on Lake Washington and Rainier Avenue South in Seattle.

In the 1960s, a lane-use signal system was added to improve peak commute traffic.

During peak commute times, the signals were used to make the center two lanes reversible.

[9] On the latter date, the old tunnel and floating bridge closed to all traffic, for renovation that was originally expected to take three years.

[9][10] When a long section of the Murrow Bridge sank during a storm in 1990, the reopening was delayed by about one year, until 1993.

The reversible lanes in the older tunnels had been separated only by painted lines on the roadway surface, but the reversible lanes on the rebuilt and expanded freeway (which use only the newer, 1989 tunnel) are separated by concrete barriers, to improve safety.

[13] Inside the older tunnels, which had been arch-shaped, the ceiling and walls were made square/rectangle, matching the shape of the "lidded" section.

The reversible roadway served as express lanes for transit buses and carpools (2+ people) during peak commute periods until 2017.

The express lanes were closed in June 2017 for the construction of the East Link light rail project, which will extend Link light rail service from Seattle to Bellevue and Redmond in 2024-2025.