In a press event at Mayor McGinn's office a consultant, Dr. Thom L. Neff, hired by the Mayor, cited high risks for the Deep-Bore Tunnel project now being considered to replace the Alaskan Way Viaduct. Seattle Department of Transportation Director Peter Hahn joined Mayor McGinn on the panel.

Dr. Neff said the project held more risk than the Boston "Big Dig" and pointed out the variety of soils the tunneling machine would bore through and added that this was one of the riskiest and most complicated projects he's ever been asked to evaluate, and one that guaranteed an "unknown outcome" regarding price, time, and geological challenges. He cited sticky clays, flowing sands, abrasive materials and boulders up to eight feet in diameter that stand in the way, the fact that the tunnel would be bored below sea level, and that the tunnel, at 54 feet in diameter, would be the world's largest of its kind.

In the wake of Dr. Neff's report Mayor McGiinn reiterated his position that he would acquiesce to the City Council's wishes and sign off on the tunnel project that they unanimously endorse, but only if the city is shielded from cost overruns.

"All I can do is keep asking this question," the mayor told the West Seattle Herald after the press conference. "When I ask it they're going to have to say why we should spend all this money. Then the public will ask 'is it worth it?' But right now the City Council says its worth it and the Legislature says it's worth it, but not if either of us have to pay cost overruns is it worth it. There are those who suggest we should have a referendum on (the tunnel) and my view is I agree. it's a significant financial import, and people should speak up."

The conclusion reached by Dr.Neff, and the Mayor seemed to be that with increased risk and complication comes increased unknown cost. This strengthened the Mayor's resolve to avoid sticking Seattle taxpayers with what he now believes are extremely likely cost overruns.

According to the Press Release, Dr. Neff is a strategic infrastructure consultant with significant experience in the planning, research, design, construction, and operation phases of a wide variety of civil and heavy construction projects presented his preliminary findings on the risks associated with the state’s proposed deep-bore tunnel project.

Dr. Neff is based in Boston, Massachusetts and has worked on projects both in the U.S. and overseas. Neff has worked in the public and private sector, and held a number of academic positions related to civil and environmental design and construction. On Boston’s $14.5 billion Central Artery/Tunnel Project, he was responsible for managing design and construction efforts in the areas of geotechnical, environmental, historic preservation, archeology, and facility deformation monitoring and control.