Seattle SR99 Tunnel
Photo copyright Washington State Department of Transportation (CC BY-NC-ND 2.0)

Facts About Seattle’s Tunnel Choice

Frequently Asked Questions About Seattle's Tunnel Choice from Cascadia Center for Regional Development

When did state and regional leaders reach a consensus on replacing the Alaskan Way Viaduct?

On January 13, 2009, Washington Governor Christine Gregoire, Seattle Mayor Greg Nickels, and then-King County Executive Ron Sims announced that together they had come to the decision to support tearing down the aging Alaskan Way Viaduct and replacing it with a technologically advanced deep bored tunnel, improvements to transit and surface streets.

Did the decision ever become state law?

Yes. Legislation authorizing and providing funding for the tunnel passed the state senate and house last spring. On May 12, 2009, in a ceremony at the Seattle Aquarium, Governor Gregoire signed into law the bill that commits the State to tearing down the viaduct and replacing it with a deep bored tunnel.

What exactly is the Tunnel+Transit alternative, and why did our region’s leaders choose it?

The Tunnel+Transit option combines a deep bored tunnel with the best elements of the surface street option. It accomplishes what other hybrid scenarios would not have been able to. It preserves throughput, reduces construction and operating impacts to businesses and residents, increases transit service, creates jobs, provides a long-term return on investment at a reasonably affordable price, has low environmental impacts, and maximizes new open-space on the waterfront.

How did the Tunnel+Transit alternative emerge as a viable solution?

In early December 2008, a state, county and city project team tasked with making recommendations to the region’s three executives about replacing the viaduct had identified two final choices: either an elevated replacement or a surface street option. Upon learning that the project team had not included the deep bored tunnel as an option, the Stakeholder Advisory Committee, a group of local civic, business and labor leaders created by the governor in 2007 to study viaduct replacement options, announced that, based on the cost-benefit analysis they had seen from Cascadia Center, Arup and other tunneling experts, the deep bored tunnel should be under consideration. In response, a critical December 16 workshop was convened where tunneling experts emphasized that tunnel costs could be under $2 billion and completed in five years or fewer. The data was compelling enough that the governor postponed the decision about the viaduct replacement to allow for several more weeks of study and consideration. Several weeks later, on January 13, Governor Gregoire, then-County Executive Sims and Mayor Nickels announced their decision to select the deep bored tunnel option.

It seems like the debate about the tunnel has been going on for decades. How long have Cascadia Center and Discovery Institute been involved in the issue?

As just about anyone who follows Washington politics knows, what to do about the elevated highway hugging Seattle’s downtown waterfront has occupied the city for years. As early as 1973, two then-Seattle city councilmen, John Miller (co-founder of Discovery Institute’s Cascadia Center) and Bruce Chapman (founder of Discovery Institute) suggested tearing the viaduct down and replacing it with a tunnel. The beginnings of the contemporary debate, however, really began after the Nisqually earthquake shook Seattle and damaged the viaduct in February 2001. Eight years later, in January 2008, with the formation of a committee to review options for the viaduct, the replacement discussion had moved from a walk to a sprint.

As part of its long range plan for the region, and since its founding in 1993, Cascadia Center has supported a tunnel as a viable replacement for the Alaskan Way Viaduct. In addition to writing and talking about the issue, Cascadia has sponsored several important conferences and reports to help educate decision-makers about advances in tunneling technology. In Fall 2006, for example, Cascadia commissioned a study of deep-bored tunnels by Arup, a leading worldwide engineering and consulting company. One year later, on December 14, 2007, Cascadia and Arup hosted an international tunneling forum in Seattle, bringing experts from around the world to engage with local government and business leaders to better understand the advances in tunneling technology. Last year, in December, Cascadia released its Arup-Cascadia report, “Large Diameter Soft Ground Bored Tunnel Review.” An update to the 2006 report, this one included samples of reported cost per mile of completed large diameter highway tunnels around the world.

But didn’t the region vote against a tunnel? And if so, why didn’t officials listen to the voters?

Regional leaders actually did listen to their constituents. The decision about a deep bored tunnel came about after the region voted no on two other options – a rebuild of the elevated viaduct, and a cut-and-cover trench along the waterfront that would have been very disruptive to build. The advisory votes sent Puget Sound leaders back to the drawing board. For 18 months, elected officials and the stakeholders committee looked at other options. They did not pursue the surface option because it would have created gridlock. But they did recommend a new tunnel option, bored under downtown, because it would avoid the massive disruption during construction and once built, would move enough traffic, along with more busses, to keep Seattle moving and protect our economy. So, in fact, the Tunnel+Transit plan is directly responsive to the voters.

What are some of the arguments against the deep bored tunnel?

The proposed deep bore tunnel, while the best option on the table, has its detractors. Some legitimate arguments against the tunnel include the fact that current planning doesn’t allow for access and egress from downtown. Additionally, the carrying capacity favors transit over cars – perhaps a short-sighted decision given growth projections for the Puget Sound region that will inevitably result in more vehicles on the roads. Tunnels today can be built so trucks with explosive and dangerous material may be carried through them. The planned tunnel for Seattle, while advanced, won’t be able to accommodate that type of material. Of course, there are legitimate arguments about cost. Any price tag of $4.2 billion is cause for reflection. However, when total life-cycle costs are considered, the Tunnel+Transit option is a very good value for the needs of the state and region.

Is it true that the tax increase needed to pay for the tunnel — projected to be $930 million by some estimates — could be the largest in the history of Seattle?

No, that’s not true. In fact, when the voters of Seattle approved the monorail, they authorized a $1.75 billion tax increase, almost double this amount, with no other governments as partners. And over the years, other big projects such as Forward Thrust were a far bigger obligation, relative to the region’s ability to pay, than this project. Seattle voters have a history of stepping up to solutions, but what’s different about this plan is about three-quarters of the cost will be borne by other government partners. Under the $3.6 billion surface option, local taxpayers might be stuck with considerably more of the cost.

If the state’s funds aren’t used for the tunnel, can they be used elsewhere?

No. The legislature approved the gas tax money just for the tunnel. Gas taxes can only be used for roads, so this money can’t be used for other things. Also, getting to use state highway funds is very competitive. The legislature approved $2.4 billion because the tunnel would keep goods and people moving on a major state highway. The $3.6 billion surface option won’t accomplish that, so the legislature could easily decide to move those funds to other important projects outside of Seattle.

Are there concerns about cost overruns and how that might be carried over to taxpayers?

Big projects don’t always have cost overruns. In fact, right here in Seattle, the Sound Transit bored tunnel through Beacon Hill came in on budget. The bids for the Sound Transit tunnel from Capitol Hill to Montlake just came in 20 and 22% below budget. And the state’s budget for the bored tunnel under downtown has a cushion built in of nearly $200 million more than the actual estimate. The real issue is managing the risks prudently – doing the right soils analysis, hiring the right experts, getting them to share in the risk.

How will the tunnel impact the environment?

Compared to other options, the Tunnel+Transit plan is much better for Puget Sound. The tunnel can capture and treat both air pollution and surface runoff and it will actually reduce the toxics going in to Puget Sound. The $3.6 billion surface option will increase runoff and air pollution and be worse for Puget Sound. The region should, of course, be concerned about its carbon footprint, and the $3.6 billion surface option would have more carbon emissions than the tunnel plan. Why? In the surface option, studies show traffic would be so tied up that even if many more people took transit there would still be more emissions from all the vehicles just idling in gridlock.

Does the Tunnel+Transit plan help shift people from cars to transit, and if so, how?

The Tunnel+Transit plan does shift people from cars to transit and it does not build more roads. But remember, Seattle is a port city and it must move a lot of freight to sustain that important economic engine. It is also an hour-glass shaped city, with only two north-south arterials. The transit part of the tunnel plan would provide a major new opportunity for people to get out of their cars, while the tunnel would allow vehicles that need to pass through the central city to move quickly and keep them from crowding downtown streets. This is critical, because a study has shown that even partial closure of the viaduct will cripple Seattle’s economy, costing more than 20,000 jobs and over $2 billion a year in economic activity. Seattle would be ill-advised to give up its ability to move people and goods. The Tunnel+Transit plan is the right combination of both systems.

Cascadia Center

Founded in 1993, as the Cascadia Project, Discovery Institute’s Cascadia Center for Regional Development is an important force in regional transportation and sustainable development issues. Cascadia is known for its involvement in transportation and development issues in the Cascadia Corridor, Puget Sound and in the U.S.-Canadian cross-border realm. We’ve recently added to that mix through a major program to promote U.S. efforts to reduce reliance on foreign oil, including the earliest possible development and integration of flex-fuel, plug-in, hybrid-electric vehicles.