Alaskan Way Viaduct tunnel claims: Who's right?

City and state leaders signed an agreement nine months ago to replace the crumbling Alaskan Way Viaduct with a deep-bore tunnel. Even so, the tunnel has become the biggest and most contentious issue in the Seattle mayor's race.

Businessman Joe Mallahan supports the current plan: $3.1 billion for a four-lane tunnel and new Sodo interchange, plus hundreds of millions in city money for a waterfront promenade, utility relocations and major east-west streets.

Former Sierra Club leader Mike McGinn says he will fight the plan, which he says costs too much and encourages dependence on cars. He wants to use the state's tunnel money to widen Interstate 5 and add bus service once the viaduct is gone.

The candidates have made dozens of claims about project costs and other details. Here's a look at how accurate their statements have been:

CLAIM: McGinn says if a tunnel isn't built, the $2.4 billion in state gas taxes set aside for it would be available for his plan to improve I-5, surface streets and transit.

ANALYSIS: The state constitution requires gas-tax money to be spent on highways, city and county streets or ferries, which would allow McGinn's plans for I-5.

But the state Department of Transportation (DOT) argues that buses are ineligible, based on state Supreme Court decisions.

McGinn counters that for buses, $500 million could be drawn from the state funds.

He said the state has often spent highway funds on buses to help people travel during construction. The state's current tunnel plan offers $30 million for construction-related transit, a figure McGinn thinks could be increased greatly.

McGinn gets the $500 million from a surface/transit concept the state released a year ago, listing $476 million for buses, park-and-ride lots and a downtown streetcar. The state didn't say it would fund that entire amount.

McGinn also would face a political obstacle: Senate transportation Chairwoman Mary Margaret Haugen, D-Camano Island, thinks lawmakers across the state would tap the $2.4 billion for their hometown road projects if the tunnel deal falls apart.

CLAIM: Mallahan has called the $2.4 billion for the tunnel project "stimulus" money.

ANALYSIS: A reference to stimulus money might give the impression that Mallahan is talking about federal funding intended to help get the country out of recession.

In fact, no money from the federal stimulus is going to the tunnel.

Mallahan said, after The Seattle Times-CityClub debate Oct. 5, that he was only making the general point that tunnel construction would create jobs.

Seattle has received $15.4 million in federal stimulus aid for the Spokane Street Viaduct widening — part of the overall tunnel project — and has applied for $50 million for the east Mercer Street reconstruction project.

CLAIM: McGinn says drivers in the tunnel would pay $6 in tolls each way.

ANALYSIS: The Legislature decided $400 million of the tunnel's cost must be raised through tolls but left details unresolved. So it's true drivers would pay something.

A year-old study by state consultant Parsons Brinckerhoff suggests afternoon peak fares of $2.25 southbound and $1.75 northbound (in 2007 dollars), based on 61,000 trips a day. The DOT has since given four scenarios to the state Treasurer's Office for review but won't release those this week.

Ron Paananen, the state's deputy urban-corridors director, said the scenarios assume a peak toll somewhere between $2.40 and $4.20 each way, and lower off-peak tolls. "None of the scenarios that we sent over had toll rates of $6," Paananen said.

McGinn says a $6 toll would be needed because he believes only 26,400 drivers a day would use a tunnel because it would lack mid-downtown exits. (The viaduct now carries 109,000 cars a day, and 63,000 use the adjoining Battery Street Tunnel.)

CLAIM: McGinn says 70 percent of Seattleites voted against "the deep-bore tunnel."

ANALYSIS: Seattle voters have never voted on a deep-bore tunnel. In two separate measures on a March 2007 Seattle advisory ballot, voters rejected both an elevated highway and a four-lane, cut-and-cover "tunnel lite," which would have torn up the waterfront for years.

McGinn insists that the tunnel-lite vote showed citizens don't want an outrageously priced tunnel — of either sort. McGinn has said that if he wins, that would be his mandate to fight the deep-bore tunnel.

CLAIM: Mallahan says people who own property near the tunnel — not all taxpayers — would pay for cost overruns.

ANALYSIS: The Legislature's tunnel bill says "any costs in excess of two billion eight hundred million dollars shall be borne by property owners in the Seattle area who benefit from replacement of the existing viaduct with a deep bore tunnel."

Mallahan seems to be taking that passage at face value, though even some lawmakers say it is unenforceable.

"The amendment has no legal standing" because it's too vague, says Rep. Judy Clibborn, D-Mercer Island.

McGinn has focused on the clause to argue that electing Mallahan would amount to writing a blank check for cost overruns.

The state, not the city, would write, finance and manage the tunnel and Sodo highway contracts.

Mallahan says one of his first priorities in office would be to lobby the Legislature to change the bill.

Even if the project stays on budget, the cost of utility relocation — around $248 million — would be passed along to ratepayers around the city.

CLAIM: Mallahan says, "The biggest driver of cost overruns is delay."

ANALYSIS: McGinn says the tunnel will face cost overruns, but Mallahan says McGinn is causing cost overruns by insisting on reconsideration of the tunnel.

On the other hand, delays inadvertently gave tunneling technology time to mature — making a bored tunnel (theoretically) cheaper than the state's earlier tunnel concepts.

Mallahan says his business knowledge has taught him that hesitation would be costly.

McGinn points to studies by Oxford scholar Bent Flyvbjerg, who has found that internationally, tunnel projects exceed their original estimates by almost one-third. "Not being realistic about the cost is the biggest driver of cost overruns," McGinn says.

A Seattle tunnel is only 10 to 15 percent engineered so far.

Mike Lindblom: 206-515-5631 or mlindblom@seattletimes.com