Emergency Transportation Operations

Highway Evacuations in Selected Metropolitan Areas: Assessment of Impediments

Seattle, Washington

#9-Most Congested
#15-Population (3,345,000)
INRIX® National Traffic Scorecard 2009

map of Seattle, Washington

The Plan

Washington State DOT (WSDOT) respondents reported that while Seattle has no evacuation plan, they maintain a well-developed Emergency Response Plan that addresses many areas critical to evacuating at-risk populations. Many of the plausible scenarios envisioned by Puget Sound planners are limited to smaller communities and groups of people so the thought of evacuating the whole city seems extremely remote. Nevertheless, they noted that the plans are regularly activated so they have significant experience in executing emergency operations. For example, in 2009, WSDOT coordinated and planned for evacuations in response to flooding risks in the Green River Valley. The WSDOT also worked with the State Emergency Management Division on evacuation planning along with local jurisdictions including Seattle and conducted a technical assistance visit to San Diego to discuss evacuation practices.

Authorities noted that they would rather have people stay put, given the threats endemic to the region. For example, if Mt. Rainier erupted violently and suddenly, Puget Sound authorities would direct people to higher ground and avoid putting thousands of people on the highway network that would be vulnerable to debris flows and flooding. Respondents expressed the view that for the type of threats they face, conducting mass evacuation operations would not be the first thing that they would want to do.

The Puget Sound Region recently received a Federal grant to address evacuation planning. The DHS/FEMA RCPGP provides catastrophic events planning grants to the 10 highest risk Urban Areas and surrounding regions. The objectives of the grant funding include: (1) addressing shortcomings in existing plans, (2) building regional planning processes and communities, and (3) linking operational and capabilities-based planning with resource allocation.

The Puget Sound Catastrophic Preparedness Planning Region constitutes an eight-county region that includes Island (city: Oak Harbor), King (cities: Bellevue, Kent, Renton, and Seattle), Kitsap (city: Bremerton), Mason (city: Shelton), Pierce (city: Tacoma), Skagit (city: Mount Vernon), Snohomish (city: Everett), and Thurston (city: Olympia) counties.

Top Highway Impediments

Top Highway Impediments

  • Congestion
  • Limited Infrastructure
  • Insufficient Responder Resources to Manage an Evacuation

During the interview, they noted that Seattle has higher priorities than mass evacuation planning. Moreover, Seattle must deal with moving people around bodies of water or mountain ranges that constrain transportation and limit the potential for evacuation routes. However, information presented in the interview identified a few impediments that may impact effective large-scale, mass evacuations from the Seattle area, including:

  1. Congestion - Based upon everyday congestion, Puget Sound officials know where their bottlenecks would constrain a mass evacuation.
  2. Limited Infrastructure - Although interviewees indicated known road bottlenecks would constrain a mass evacuation, interviewees suggested that building a roadway network large enough for a possible mass evacuation of the city would not constitute good fiscal stewardship since excess capacity would either be wasted, immediately filled with traffic from new development, or create negative environmental impacts from such construction in the area.
  3. Insufficient Responder Resources to Manage an Evacuation - Authorities noted that, even if they could accommodate a mass evacuation, they don't have the responder resources available to direct and manage a mass evacuation operation on the NHS roads.

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