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Still Not Digging The Tunnel

2011 July 24
by dan bertolet

< Seattle's Alaskan Way Viaduct >

I’ve hacked out an absurdly huge volume of words criticizing Seattle’s proposed deep-bore tunnel ever since it was first announced back in January 2009 (see list at the bottom of the post). And I have mainly hit on the big picture, that is, why the tunnel is such a bad investment given massive trends such climate change, peak oil, sprawl, public health, and evolving demographics and preferences—in short, largely the environmental point of view.

So it was gratifying to see a cadre of my favorite environmentalists—whose names are much bigger than mine—going public last week with such a powerful indictment of the tunnel. To me, the heart of the issue is summed up well in the last sentence:

What our community needs now, in these dark economic and political times, is a brave and pragmatic, “Hell, yes! We can do better than a buried highway.”

Interestingly, however, much of their “environmental” argument concerned functional aspects. In particular, the remarkable truth that—as was first reported by Sightline, and then expanded on by the Stranger—modeling in the Final Environmental Impact Statement (FEIS) shows that in terms of traffic congestion impacts, a tolled tunnel is barely better than closing the viaduct and doing absolutely nothing else.

Continuing that line of thought, if we assume for the moment that the only thing that matters in the world is traffic congestion, then the key metric is vehicle hours of delay (VHD). The table below shows the FEIS’s projected VHD in 2030 for the tolled tunnel, the tolled elevated, the I5-surface-transit option (ST5), and closing the viaduct.

< Vehicle hours of delay (VHD) in 2030 for various options; source: WSDOT >

A few things pop out. First, ST5 is the clear winner when it comes to mitigating congestion in Seattle’s city center. Note that ST5 is the very plan that the pro-tunnel “Let’s Move Forward” campaign has disparaged as “McGinn’s surface gridlock.” Also, given the numbers showing that ST5 is a better performing solution for downtown Seattle than the State’s preferred tunnel option, it’s ironic that the Downtown Seattle Association is the largest single contributor so far to Let’s Move Forward.

Second, for the four-county region, compared to the tolled tunnel ST5 would only result in about one percent more vehicle hours of delay. Is that even within the margin of error for the modeling? Nevertheless, as reported as, when the  FEIS was released, State officials touted preserving regional mobility as the justification of their choice of the tunnel. And apparently bought it, translating that one percent difference into a hyperbolic headline that reads “Surface-transit would clog regional traffic.”

Third, in terms of vehicle hours of delay ST5 performs better—both locally and regionally—than the tolled elevated, which was one of the official alternatives analyzed in the FEIS. Yet the State decided in advance that ST5 did not merit full consideration. By the way, that would be the same ST5 that was one of the original two recommended options that came out of the year-long stakeholder process, that has been vetted in multiple studies (here, here, here, here, and here), and that costs about a billion dollars less than the deep-bore tunnel. It’s hard not to conclude that the State’s dismissal of ST5 can only be the result of either an attempt to stack the deck, or incompetence.

Given the modeling data, an objective observer might conclude that choosing the tolled tunnel over ST5 comes down to Seattle taking one for the (regional) team. That is, Seattle’s mobility must get worse so that the region’s mobility can get better (even if only one percent better). And maybe that really could be a justifiable choice, depending on the circumstances. But I strongly suspect that’s not how most tunnel boosters who live in Seattle would prefer to see it. And it’s certainly not how most of the State’s electeds have postured on it, seeing as they passed legislation making Seattle property owners liable for cost overruns.

So then, back to the the original assumption that nothing matters more than moving more cars faster. During the latter half of the last century, that was pretty much the operative rule for transportation planning. But now we’re supposed to know better. Now that we understand the web of connections between transportation, land use, and sustainability, we should no longer accept small, narrowly focused gains at the expense of holistic, long-term solutions. For example, a two-mile underground freeway might result in a relatively small, local reduction in runoff pollution to Puget Sound, but a paradigm-shifting plan like ST5 has the potential to catalyze systemic change, and the resultant reduction in car-dependence would have a far greater cumulative positive impact.

The challenges and opportunities of the coming decades are so profound that we’ve got to do better than settle for major infrastructure investments based on last-century thinking. And to better appreciate why so many of us so-called environmentalists are stubbornly resistant to further compromise—as in, just build the tunnel because we have to do something—I would recommend Bill McKibben’s latest book, Eaarth, the thesis of which is that we no longer live on the same planet, and we better start planning our future accordingly. McKibben, founder of, recently had this to say regarding Seattle’s deep-bore tunnel:

‎The era of expensive, vulnerable, car- centric megaprojects is ending around the world, as more and more cities plan for a durable, resilient, diverse future. Not cars-in-a-pipe, but bikes, buses, and all the things that make a city a city.

If you agree, Protect Seattle Now, the campaign to reject the “tunnel referendum,” could use any support you can offer.


Still Not Digging The Tunnel Epilogue: The Dan Bertolet Tunnel Reading List: