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Urban transportation -- United States, Climatic changes -- Alaska, Climatic changes -- Washington, Climatic changes -- Oregon


The states in the Pacific Northwest and Alaska region share interconnected transportation networks for people, goods, and services that support the regional economy, mobility, and human safety. Regional weather has and will continue to affect the physical condition and serviceability of these networks, yet the nature of climate changes and their potential impacts on the regional transportation system and its use are very poorly understood. The world’s leading climate scientists, such as the Intergovernmental Panel for Climate Change, have reached consensus that global climate changes are being observed and will continue into the future, particularly increasing temperatures. Given this fact, the widely diverse topography, climate regimes, and localized variability of impacts within the region complicate efforts to understand and plan for adapting to the potential impacts of climate change on the regional transportation system. The rising costs of building and maintaining reliable transportation infrastructure place tremendous pressure on transportation planners, engineers, researchers and policy makers to deliver resilient transportation systems and maximize return on investment. As such, there is an urgent need to synthesize information to characterize the regional impacts of climate change to support the development of economical and resilient adaptation strategies.

Climate impacts are posing continued challenges for state departments of transportation (DOT). Changing weather patterns and their associated physical, financial, and social impacts are affecting or will affect the way transportation professionals finance, plan, design construct, operate, and maintain multimodal transportation infrastructure. Many state transportation agency procedures and practices were developed without full consideration of the likely impacts of climate change. For example, more frequent, high intensity precipitation events and associated floods may lead to expensive and unpredictable catastrophic failures of roads and bridges designed with outdated hydrologic data. DOTs could experience hundreds of millions of dollars in infrastructure damage that potentially could be avoided with more robust data collection, planning, and design tools/methods for managing risks. Likewise, climate-related socioeconomic changes may also be occurring, but transportation planners are currently ill-equipped to analyze them and may be delivering transportation projects that do not address future needs. Decisions made today on the planning and design of the regional transportation system will affect resiliency of the system as region tries to adapt to climate change. Making well informed and thoughtful decisions now will help avoid costly modifications and disruptions to operations in the future.

This report is built on several significant reports and projects that have been recently published. In 2008, the Transportation Research Board released the Special Report 290: Potential Impacts of Climate Change on U.S. Transportation, which primarily focused on the consequences of climate change for U.S. transportation infrastructure and operations. The report also offers recommendations for both research and actions that can be taken to prepare for climate change. A similar study released by U.S. Department of Transportation, Impacts of Climate Change and Variability on Transportation Systems and Infrastructure: Gulf Coast Study, Phase I, explores the vulnerabilities of transportation systems in the Gulf Coast region to potential changes in weather patterns and related impacts, as well as the effect of natural land subsidence and other environmental factors in the region. The area examined by the study includes 48 contiguous counties in four states, running from Galveston, Texas, to Mobile, Alabama. In addition to these national reports, there are a variety studies that look at the scenarios of future climate for the Pacific Northwest. Most notably are the Climate Impacts Group’s Washington Climate Change Impacts Assessment and the Oregon Climate Change Research Institute’s Oregon Climate Assessment Report, which developed climate change scenarios for Oregon and Washington State.

The objective of this research project was to conduct a preliminary vulnerability assessment of the risks and vulnerabilities climate change poses to the surface transportation infrastructure system in the Pacific Northwest and Alaska region. The report:

  • synthesizes data to characterize the region’s climate,
  • identifies potential impacts on the regional transportation system,
  • identifies critical infrastructure vulnerable to climate change impacts, and
  • provides recommendations for more detailed analysis and research needs as appropriate to support managing risks and opportunities to adapt multimodal surface transportation infrastructure to climate change impacts.

Transportation professionals and policy makers can use the results of this report to build a breadth of knowledge and information on regional climate change impacts, understanding vulnerabilities of the transportation system and begin creating more quantitative risk assessment models.


This study 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 The U.S. Department of Transportation, Federal Highway Administration.

This is the final report, OTREC-RR-12-01, and can be found online at:



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