Tunnel Option Extends Life of Elevated Highway Despite Known Risk of Earthquake

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Recent events in Japan have added yet another twist to the ongoing saga of Seattle's Alaskan Way Viaduct. Before the earthquake and resulting tsunami, the Mayor and City Council duked it out over whether or not the City of Seattle would commit to replacing the damaged Alaskan Way Viaduct with a deep bore tunnel along the waterfront. The Mayor lost that specific battle and the city is moving ahead with a $4.2 billion project.

Oddly, during that discussion, the City Council evoked the fear of another earthquake that would ultimately bring down the double-decker elevated highway. Yet it is precisely the tunnel plan that keeps the viaduct standing until 2016, not 2012, which was the stated goal. Mayor McGinn has called them out on this, stating, "The city council has chosen the option that leaves the existing viaduct up the longest." And earlier this week, Mayor McGinn took a stand and urged the closing of the highway by next year in light of the recent earthquake in Japan.

If you have missed all this recent discussion or the history overall, be sure to check out Dominic Holden's March 15th piece in The Stranger, "Stop the Insanity." He provides a great summary of the problems with proceeding with a tunnel and raises a call to arms to get the issue on a city referendum for the voters to reject the tunnel for a second time. He makes a strong case for the surface and transit option and takes the City and State to task for signing contracts before the environmental review is complete -- a clear violation of State code.

After reviewing how a surface/transit option could work and be paid for using existing funding sources, Holden states, "So if this is about bringing the viaduct down sooner rather than later, we should build surface/transit. If it's about spending money wisely, we should build surface/ transit. If it's about the waterfront or bringing shoppers to downtown businesses, we should build surface/transit. If it's about saving lives, we should build surface/transit." Holden also promotes the efforts of Protect Seattle Now, which is quickly working to gather 16,000 signatures by March 25 for a public referendum.

Here's a quick and dirty summary of Holden's piece in Myth/Fact form:

Myth: The tunnel will open up the waterfront more than a surface transit option.
Fact: WSDOT's own research found that the tunnel and a surface/transit option produce identical traffic flows along the waterfront under the assumption that the there are no tolls. Once tolls are added, more vehicles will be added to the waterfront under the tunnel scenario as people avoid having to pay the toll. (And the city will have no money to mitigate this traffic diversion since it will be tied up with paying for the tunnel.)

Myth: The tunnel is the only way to maintain traffic flow and preserve capacity.
Fact: Nearly two-thirds of the 110,000 vehicles a day that currently use the elevated road are not predicted to use the tunnel. This is due to two main issues -- most drivers are predicted to avoid the $3.50-$4 tolls and the 1.7-mile tunnel will have no exits.

Myth: The tunnel is essential for freight mobility in the region.
Fact: Currently, only 4% of viaduct trips are made by medium to heavy trucks and three-fifths of that truck traffic begins or ends downtown. Since the tunnel will have no exits into downtown, it will force most of the freight traffic onto city streets anyway.

Myth: The tunnel is needed for traffic that needs to bypass downtown.
Fact: WSDOT's own research shows that the pattern and flow of traffic on the elevated highway is indicative of morning and evening commutes into the employment core -- not one of long-haul through trips. This is a point Smart Mobility made back in 2007 when working with CNU and the Center for Neighborhood Technology to investigate WSDOT's assumptions. They noted that "most of the viaduct traffic during peak traffic periods gets on or off [the viaduct] in central Seattle, and is not through traffic."

Myth: The surface/transit option will lead to gridlock.
Fact: WSDOTs own data shows that the surface/transit option performs slightly better than the tunnel in the downtown system overall, with fewer miles traveled, fewer hours traveled, and less delay. As Holden points out, the differences between the tunnel and the surface/transit option are not huge, but the essential point is that, "the much more expensive tunnel doesn't perform any better than the surface/transit."

Myth: The tunnel is needed for growing traffic volumes.
Fact: Congestion in Seattle has dropped by 32 percent since 2006. An analysis by Scott Bernstein of CNT using recent information from Seattle's DOT revealed that trips by automobile have declined by 6% from 2000 to 2009, while at the same time the population increased by nearly 10%. That equates to 14% fewer trips per capita.

Myth: The disappearing traffic under the Surface/Transit Option equates with less economic activity.
Fact: Under a no replacement future, Smart Mobility predicted that 30% of traffic will divert to the surface Alaskan Way, 25% on north and south arterials, 17% on Interstate-5, and 28% disappears. This disappearing traffic estimate has been witnessed in other highway to boulevard conversions. But does this mean less economic activity? Sure, it could mean less gas purchases, as people use services closer to home and combine more trips. Holden doesn't mention this, but Seattle should look to the CEOs for Cities report, Portland's Green Dividend, which showed how reducing the number of miles driven in a day can add billions of dollars to the local economy.


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