Climate Change Impact Assessment for Surface Transportation in the Pacific Northwest and Alaska

The Climate Change Impact Assessment (Assessment) provides a preliminary analysis of the vulnerabilities posed by climate change to the surface transportation infrastructure system in the Pacific Northwest and Alaska region. The Assessment demonstrates a method that planners, engineers, and other agency decision makers can follow when assessing the impacts of climate change on surface transportation in their jurisdiction. The Assessment was conducted for the Region X Northwest Transportation Consortium for transportation policymakers and professionals in Alaska, Idaho, Oregon, and Washington. The Assessment identifies potential impacts on the regional transportation system, identifies critical infrastructure that is vulnerable to climate change impacts, and provides recommendations for more detailed analyses and research needed to adapt multimodal transportation infrastructure to climate change impacts.

The Assessment synthesizes data, including historic regional temperature data, regional sea-level rise projections, and North American Regional Climate Change Assessment Program (NARCCAP) data, to characterize current conditions and projected changes in the region’s climate. The report highlights projected changes in temperature, precipitation, and the number of extreme events for five “regional subdomains” (coast, Cascades, desert, Rockies, and Yukon Flats). Each climate change projection is linked to their likely impacts on the surface transportation operations and infrastructure in each subdomain, including a discussion of impacts by mode and location where possible. This includes a discussion of the direct climate impacts on surface transportation (e.g., the effect changes in precipitation and temperature will have on rail, roadways, and waterways) as well as the indirect impacts (e.g., the effects of increased wildfires, pests and infestation on transportation infrastructure). The analysis presented in the report integrates this data and applies variables into a conceptual framework to evaluate vulnerability of the regional system using geographic information systems (GIS).

In addition, the Assessment uses two case studies applying the GIS and FHWA’s Vulnerability Assessment Framework to evaluate the vulnerability of critical infrastructure in parts of the region. The first case study identifies critical roadways, rail and airport infrastructure in Alaska, Idaho, Oregon and Washington focusing on impacts from flooding, landslides, permafrost thaw, and sea-level rise. The second case study examines localized impacts to major roadways, rail, bike facilities, bus routes, and streetcar and light rail in Portland, OR. The case studies focus on infrastructure and assets critical to the inter-connectivity of the region, and model the tools that can be developed to perform a statewide risk and vulnerability assessment.

The Assessment also identifies research needs and recommendations for ways that transportation professionals can assess risks in their jurisdiction, including:

  • Additional GIS data layers and better climate models for predicting the probability of events.
  • Research on road vulnerability to extreme heat events and rapid changes in thermal conditions, such as freeze-thaw effects on pavement.
  • Guidelines for conducting hazards and impacts assessments, vulnerability analyses, and developing alternative adaptation responses.
  • An overview of planning, design, and non-design adaptation strategies.  

The report concludes that resources such as high-resolution climate change models, transportation asset management systems, and GIS offer methods to incorporate climate change adaptation into current and long-range planning processes.  In particular, the report concludes that GIS is a promising tool for vulnerability assessments. It is also recommended that results from climate change impact assessments be incorporated into an agency’s overall planning and project development process, and updated regularly as new information and methods become available.

The Assessment was funded by the Washington Department of Transportation, and was conducted in cooperation with the Oregon Department of Transportation, Idaho Transportation Department, Alaska Department of Transportation, Oregon Transportation Research and Education Consortium, the Alaska University Transportation Center and FHWA.  It built upon several previous reports and projects, including: the “Special Report 290: Potential Impacts of Climate Change on U.S. Transportation,” issued by the Transportation Research Board in 2008; “Impacts of Climate Change and Variability on Transportation Systems and Infrastructure: Gulf Coast Study, Phase I,” released by the U.S. Department of Transportation; “Washington Climate Change Impacts Assessment,” issued by Washington state; and “Oregon Climate Assessment Report,” released by Oregon state. The North America Regional Climate Change Assessment Program (NARCCAP), a project based at the University Center for Atmospheric Research in Boulder, CO, was used as the source for downscaled climate data and the source for climate model projections in this report. The NARCCAP climate variables examined for this project were precipitation and temperature, both on multiple scales at 50 km/31 mile resolution.


This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on December 29, 2014.


Publication Date: January 2012

Authors or Affiliated Users:

  • John MacArthur
  • Philip W. Mote
  • Jason Ideker
  • Miguel Figliozzi
  • Ming Lee

Related Organizations:


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Resource Types:

  • Assessment

States Affected:


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