Proposed tunnel replacement to the Alaskan Way Viaduct

Cost Estimate: $4.25 billion
Length: 2 miles
Location: Between SoDo and South Lake Union

Videos:
Rendering of the new tunnel:

Boring machine:

Video simulation of an Alaskan Way viaduct collapse—worth watching:

On January 12, 2009 numerous local and state government agencies unveiled plans for a four-lane, 2-mile long bored underground tunnel. The tunnel would have a south portal in SoDo, near Qwest Field, and a north portal in South Lake Union. On March 4, 2009, the state senate passed a bill endorsing the tunnel option.

The project is estimated to cost US$4.25 billion, with $2.8 billion coming from the state and federal governments to cover the tunnel boring and a new interchange in SoDo.[2] The replacement project also includes the following projects and funding sources:

• The city of Seattle will fund surface street improvements, utility relocation, and repairs to the Alaskan Way Seawall, which was also damaged in the Nisqually earthquake.
• Since the proposed tunnel will contain two lanes in each direction as opposed to the viaduct’s three, and no Western Avenue exit to serve the Belltown, Interbay, and Ballard areas.
• The Port of Seattle is considering funding part of the project in SoDo.
• The state senate’s bill calls for a study regarding $400 million being collected through tolls.