We've been poring over the draft environmental impact statement (DEIS) for the deep-bore tunnel, and it doesn't look good, at least from an environmentalist point of view. In a way, that's kind of a "duh" statement—it's a massive new highway on our waterfront—but the DEIS provides some specific data about just how bad the impact is going to be. Additionally, it's interesting to see which data points the state department of transportation (WSDOT) deliberately left out—something Mayor Mike McGinn referred to repeatedly in his comments on and objections to the impact statement.

First, while the ostensible purpose of the viaduct replacement project is to effectively move people and goods, not cars, the DEIS refers repeatedly to moving vehicles, not people and goods. (For example, from Chapter 1, "To protect public safety and provide essential vehicle capacity to and through downtown Seattle, the viaduct must be replaced.")

The DEIS found that vehicle hours driven (a common measure of congestion) in the central city would increase about 7 percent if the deep-bore tunnel was built compared to 2015 projections for the current viaduct, "likely due to changes in access proposed with the Bored Tunnel Alternative"—i.e., the lack of any exits downtown. The study didn't look at what would happen to traffic volumes if the viaduct was taken down and replaced with transit and improvements to I-5 and surface streets downtown, since it didn't consider the I-5/Surface/Transit alternative.

Travel times along the route of the new tunnel are expected to stay about the same or "improve"—which is, of course, another way of saying people will be able to drive even faster. Depending on your perspective, that's either a good or a bad thing. Traffic volumes, however, will increase near the  Battery Street Tunnel (about 17,000 cars) and will decline by about 30,000 vehicles through the center of downtown, as 28,000 vehicles shift to city streets. (The state expects only about 1,000 drivers to switch to I-5).

Traffic noise would be near federal limits at 40 of 68 sites along the route, which is a little better than the 48 sites that currently exceed noise limits.

Throughout the report, the state assumes that things like greenhouse gas emissions and energy consumption by vehicles will increase because vehicle travel is expected to increase in the region by 2030. This, of course, contradicts state policy that mandates 50 percent reductions in emissions from 1990 levels by 2050, largely through reductions in the use of personal automobiles of 50 percent by 2050. The DEIS briefly mentions these state mandates, but does not address the contradiction between the goal of reducing emissions and the fact that the tunnel project would actually increase them.

Regardless, WSDOT determined that greenhouse gas emissions are not among the "controversial issues" surrounding the project, telling McGinn in its response to his comments, "Per discussion with City and WSDOT staff -this is not a controversial issue for this project." Nor were greenhouse gas reductions included in the project's "purpose and need" statement, despite the state's commitment to reducing greenhouse gases from cars.

Also excluded from "controversial issues": Any discussion of the provision in state law stating that Seattle-area property owners are on the hook for any cost overruns. Given the fact that that provision may lead to a citizen referendum to stop the project, that seems like a pretty glaring omission.

The DEIS notes that tunnel construction will produce 27 metric tons of CO2 emissions, which the report calls "negligible" compared to "the existing daily CO2e emission estimate of 39,189 metric tons and 2015 Existing Viaduct estimate of 46,557 metric tons for the region," and that the energy consumed during construction would represent just a "small fraction" of the energy used by vehicles that use the viaduct. In his comments, McGinn asked if those estimates included the manufacture of concrete and other construction materials; in its response, WSDOT said it didn't.

Finally, the DEIS dismisses the I-5/Surface/Transit option, saying it "lacked the capacity to serve the long-term needs of the region," presumably meaning car capacity. Elsewhere, the DEIS says it rejected surface/transit because it would increase travel times and create congestion—again ignoring the possibility that implementing surface/transit would actually reduce the number of trips downtown, as people find alternatives to driving and combine or eliminate trips. The model assumes that driving will simply increase forever.

Read the documents for yourself.

Part 1

Part 2

Part 3

Part 4

Part 5

Part 6

Part 7

Part 8

Part 9

Tolling Study

Mayor