Seattle Department of Transportation director Peter Hahn wrote a letter yesterday to state DOT (WSDOT) director Paula Hammond outlining the city's concerns about a draft environmental study on the deep-bore tunnel. Hahn's concerns largely echo issues his boss, Mayor Mike McGinn, and the city council's resident tunnel skeptic, Mike O'Brien, have been raising about the tunnel, including the impact of tolling on downtown traffic, concerns about building settlement in Pioneer Square, and the fact that the study predicts more traffic over time, contradicting the state's greenhouse-gas reduction targets.

On the impacts from tolling, Hahn noted that the analysis that has been done so far assumes that "a significant amount of traffic will divert to city streets" near the north and south tunnel entrances, yet the environmental impact statement doesn't include a full analysis of traffic from tolling. McGinn has recently been touting estimates that show the tunnel carrying only between 40,000 and 45,000 cars per day if the highest potential toll, $3.30 each way at rush hour, is adopted.

Hahn also noted that the environmental impact statement shows that the tunnel will not help Seattle or the state meet their goals for greenhouse-gas emission reductions, and that it doesn't consider the impact of climate change on the project, including sea level rise, changes in local weather patterns, and temperature increases. "Any long-term infrastructure project should carefully consider scientific models for potential impacts of climate change in Seattle and the project should be designed to adapt to those impacts.

Read the whole letter, which also addresses the potential for cost overruns and the fact that the state did not seriously consider other alternatives, here.