Seattle’s viaduct replacement debate has generated an untold volume of analysis, opinion, and argument. It’s also generated at least one PhD dissertation.
Kevin Ramsey, a geography student at the University of Washington, takes a look at the way that concerns about climate change have been deployed in the debate over the replacement. (Abstract; summary; full text.) I’ll confess that I haven’t made my way through the entire 250 pages, but it strikes me as providing some fascinating analysis of the politics:
…agency planners incorporated concerns about climate change through an extension of their own established logics of transportation planning rather than through a fundamental reconsideration of Seattle’s automobile-centric transportation system.
More surprisingly, I found that stakeholders themselves helped make this happen. They did so by supporting (and even advocating) the use of travel demand models to predict the quantity of future greenhouse gas emissions from alternative viaduct replacement scenarios. Isolating the consideration of climate change to this single evaluation measure essentially enabled the issue to be treated as an afterthought in the planning process, rather than a motivator for reformulating the planning process altogether. It also ensured that the calculation of future greenhouse gas emissions was subject to the same kinds of assumptions regarding demand for automobile travel that activists had already contested for years. These assumptions were reflected in the agencies’ findings: all proposed viaduct replacement scenarios (including three that do not include a highway) were predicted to increase greenhouse gas emissions in the Seattle region to 14-15% above current levels by the year 2015.
The upshot, according to Ramsey, is that highway planners were able to essentially co-opt concerns about climate emissions into a business-as-usual approach to road building. The antidote, he says, is for advocates to level more fundamental challenges to the large systems that provide for automobile-dominated infrastructure.
Clark Williams-Derry
I’ve read about as much of this as you have, Eric—but you’re right, it fascinates me.In theory, estimating the carbon impacts of the viaduct alternatives—tunnel vs. surface vs. aerial—makes a lot of sense! In practice, though, it’s next-to-impossible. The only way to come up with the numbers is to run some big, region-wide transportation demand models. But those models aren’t particularly sophisticated, really. They take a steady increases in VMT demand as an input—a baseline assumption—not as an output. So they start out by assuming steadily increasing VMT, and then find—lo-and-behold—that carbon emissions increase about the same amount no matter what happens on the Viaduct. And besides, the effect of a 2 mile stretch of highway is vanishingly small in any region-wide model. That renders the viaduct decision irrelevant in CO2 planning.Perhaps the better way to look at this is: how much CO2 reduction in the transportation sector can you buy with $2+ billion? If you spend that money on a tunnel, you buy squat—the status quo. Spend it on demand management, and you’ve made a dent, however slight, in CO2 emissions, while still satisfying legitimate transportation needs.
Kevin Ramsey
Clark,In 2008 WSDOT, SDOT, and KCDOT did study one surface-streets viaduct replacement scenario that included a whole bunch of innovative demand management policies (see Scenario A,
Kevin Ramsey
Clark,In 2008 WSDOT, SDOT, and KCDOT did study one surface-streets viaduct replacement scenario that included a whole bunch of innovative demand management policies. This option, just like the seven other scenarios with lesser emphasis demand management, was predicted to increase regional CO2 emissions by 14% in 2015 as compared to existing conditions. Sadly, from what I can tell, none of the demand management policies made it into the bored tunnel option chosen by state, city, and county officials.Efforts to measure the carbon footprint of transportation projects and policies will always be shaped by the assumptions in agency transportation models. Agency officials and planners defend these assumptions as objective engineering practice rather than some preference for perpetuating the status quo. So I agree that, in theory, estimating the carbon impacts of the viaduct alternatives can make a lot of sense. However, until there is a massive cultural shift within our agencies of transportation planning, practice will never result in the outcomes that progressive transportation advocates are hoping for. Perhaps a better approach would be to question the whole enterprise of modeling transportation demand and system performance. Or, at minimum, we need to find ways to open it to more public scrutiny. For instance, I find it appalling that state, local, and county transportation officials refused to do sensitivity tests of the viaduct replacement scenarios—or, in other words, modeling how these scenarios might perform given a range of different assumptions about demand for trips, cost of fuel, etc. By making these details off-limits to public debate our transportation officials are in effect narrowing our collective imagination regarding what kind of city and region we can become.
Kevin Ramsey
For those who are interested, I wrote a new report based on this research. It briefly reviews my study findings and then offers practical recommendations for the development of more meaningful project-level greenhouse gas assessments. Most notably, it explains how the technique of scenario planning could be employed to assess the performance of proposed transportation projects in a range of different future conditions. Each scenarios would consist of a plausible story about future conditions such as policies (e.g., tolling), fuel prices, land use, and travel behavior. These ‘variables’ then serve as inputs for modeling studies. When evaluating the ‘carbon footprint’ of viaduct replacement alternatives, transportation planners only evaluated a single scenario which was largely off limits to public review. In doing so, they painted a picture of a seemingly inevitable future that will occur if a project alternative is chosen. A scenario planning approach, on the other hand, would clearly demonstrates that the future is not fixed. Rather it would show that the outcomes of different viaduct replacement alternatives are dependent upon future conditions which—to some extent—are within our control. Presenting model findings in this way would facilitate more meaningful policy debates about the relationship between an individual transportation project and regional transportation/greenhouse gas reduction plans.You can find a link to this report on my website: http://www.KevinRamsey.netHere is a direct link: http://tinyurl.com/2wd6qm3