Seattle has been planning to replace its Alaska Way Viaduct since 2001, when an earthquake in the region shook the above ground waterfront highway and created widespread concerns of it collapsing in the future. The question became how to replace the highly-used viaduct. A deep-bore tunnel running along the waterfront and under downtown Seattle became one option over time, competing with alternatives such as a new viaduct, a “cut-and-cover” tunnel-like highway along the path of the old viaduct, and more modest options such as simply replacing the viaduct with a boulevard that would force capacity traffic onto the I-5 freeway that runs parallel to the viaduct on the East side of downtown Seattle. None of these options have gained majority support, and the cut-and-cover tunnel and new-viaduct options were both rejected in a 2007 referendum. Nevertheless, the city and Washington State government came to an agreement to move forward with the deep-bore tunnel in 2010. Opposition groups are seeking to put it to another referendum in 2011. And while many believe there is no chance of such a referendum succeeding, the debate on the merits of Seattle’s deep-bore tunnel continued hotly. The pros and cons are outlined below.
“Alan Dyke, managing director for the high-speed rail route between London and the English Channel, said a tunnel under London was chosen because disruption and environmental mitigation requirements of a surface route through the city would been excessive. […] The Paris A86 beltway automobile tunnel holds a similar lesson. Jeff Hall is vice president of Cofiroute, a subsidiary of Vinci, one of the largest construction firms in the world and builder of A86. Hall said Paris went through alternatives — surface roads, a cut-and-cover tunnel — and rejected them due to a quality of life issue: Protection of the Parisian greenbelt. ‘A deep-bore tunnel was the only way to do this while adding capacity.'”
Dick Robbins heads The Robbins company, a Seattle-based designer, maker and operator of tunnel-boring machines (TBMs). He said to the Puget Sound Business Journal in 2007: “big advances in tunnel technology are the result of steady progress that makes tunneling cheaper, faster and safer.” In Red Robinson’s words, “New technology makes the impossible possible.”
John Reilly, a leader in the International Tunneling Association: “Politics is often focused on initial capital cost, but we must look to total life-cycle cost. Tunnels cost more to build but less to maintain. They last a lot longer than elevated structures or surface streets.”
“Spending 4.4 billion dollars now is better for Seattle than spending 3.5 billion dollars years later. This is true for two reasons. First, the low construction costs we enjoy now won’t last forever. Second, the economy needs stimulus right now, not years from now when it may be overheated again. John Maynard Keynes said that to get out of a situation where the public is not creating enough demand to fuel the economy – exactly our situation – government should, if necessary, pay people to dig a hole and fill it back up again. A tunnel is a better payoff.”
Gary Lawrence, Urban Strategies Leader for Arup Consultants, said real estate improvements can help pay for the project. ‘In Asia, some rail projects are paid for entirely by the sale of air rights,’ he noted. According the Puget Sound Business Journal, “the analogy for Seattle would be the development gains that would come from removing the viaduct.”
“Construction cost overruns are a red herring because the cost of construction and materials now are at rock bottom; worst-case estimates were developed during the bubble when construction costs were expected to escalate; estimates were made following the adoption of conservative estimating procedures that assumed prices might continue to escalate; and additional risk contingency was added to the project over and above that for more traditional construction projects. Because the construction industry is on its knees now, the idea that construction will be cheaper in the future is absurd.”
Proponents have pointed out that Seattle’s bored-tunnel proposal would not be close to the scale of even the cut-and-cover segment of Boston’s I-93 tunnel project.
Governor Christine Gregoire: “The goal all along … was how do we open up the waterfront to make it appealing to the community at large and to tourists.”
A new report from Sightline Institute, a Seattle-based, nonprofit think tank, could dig the debate a little deeper. The report, titled “Cost Overruns for Seattle-Area Tunnel Projects,” compares high-profile tunnels recently constructed in the area […] A cost overrun of $100 million, which is just 2.4 percent of the project’s total cost, could cost a Seattle family of four almost $700, the report notes. A larger cost overrun of 25 percent could create more than $1 billion of new tax liability for Seattle taxpayers. Cost overruns for tunnel projects are common: The downtown Seattle bus tunnel experienced a cost overrun of more than 56 percent, Sound Transit’s Beacon Hill tunnel exceeded expected costs by 30 percent, and King County’s bored tunnels for the Brightwater Sewage Plant are already over budget (the final overrun is currently unknown). Overruns such as these aren’t unique to Seattle. Oxford University professor Bent Flyvbjerg surveyed 258 megaprojects from around the world, and found that 90 percent experienced cost overruns, with the average cost overrun at nearly 30 percent.”
“First, the tunnel proponents project growing traffic, but all measures show traffic declining. At the metropolitan level, the Federal Highway Administration shows a 13 percent decline in daily vehicle-miles-traveled (VMT) per capita, from 25.5 in 2000, to 22.1 in 2008. In King County, total annual on-road VMT per-household dropped 11 percent from 2000 to 2009. And Seattle DOT finds daily traffic in Seattle dropped 6.25 percent from 2000 to 2009, despite growing population; the net effect is 14 percent decline per capita.”
“proponents state that economic growth requires new capacity, but growth occurred in the face of declining traffic. From 2000 to 2009, Seattle Gross Metropolitan Product per-household rose from $125,208 to $142,419, a net increase of 14 percent. Your region is producing more while driving less, which is the right path to economic sustainability. One reason this works is that a large fraction of people in Seattle and King County enjoy urban form—small block sizes, high density of intersections per square mile—and location efficiency, meaning the accessibility that results from proximity, connectivity and choices in how to get around. As good as the economy is to you, it could be even better—and it needs to be. From 1999 to 2009, household income increased $1,108 per month, but combined housing and transportation costs increased by $808, leaving the average citizen just $300 to pay for increased food, medical, retirement, and loan expenses.”
“the debate comes down to whether Seattle needs a highway at all. Some people are convinced, to the point of religious conviction, that the loss of the highway would mean chaos. But lots of cities have gotten rid of urban highways and the outcome is inevitably positive. Cities are not for getting through, they’re for living in. Urban space should belong to people.”
“Tunnels are inherently green, contrary to what others say: 1. Tunnels last a very long time, often hundreds of years, with far less maintenance than surface improvements. 2. Because tunnels last a long time they are often a very wise investment. Witness the Burlington Northern Tunnel. Tunnels are much more resistant to seismic damage than surface infrastructure. 3. Tunnels can be repurposed. The deep-bore tunnel can be converted to transit or rail use if this makes sense in the future. And the tunnel will serve bus rapid transit well as soon as it is finished. 4. This deep-bore tunnel gives Seattle planners more flexibility to make downtown livable. For instance, the additional lanes available offer the possibility of closing some north-south surface streets to through traffic.”
While it is true that most cars use fossil fuels, more and more cars are going to be electric and clean. Cars are not inherently dirty, and therefore, a tunnel that focuses on facilitating vehicle transit is not an inherently dirty tunnel. It could easily become a clean tunnel.
“Having seen city after West Coast city make the call against car dependency and in favor of livable waterfronts, we’ve been inclined to support the Surface Transit option — a boulevard along the waterfront, with former viaduct traffic using the boulevard or finding alternate routes. The surface option is admittedly not the fastest way to move vehicles — but then, in a post-carbon era, the whole point is that the car is no longer king.”
Moving cars ended up being the metric for judging the potential success of the tunnel. But this is the wrong criteria; the focus should be on moving people.
This is mainly out of respect for the above argument, and simply validates it as a major concern within the environmental community, according to the Seattle Times
and other ways climate change could affect the tunnel.