Transportation systems are vulnerable to extreme weather and climate change impacts, such as increased temperatures, sea level rise, and more intense storms. These events threaten the ability of transportation agencies to effectively plan, invest in, operate, and maintain their infrastructure. Over the past decade, many transportation agencies have transitioned from vulnerability assessment to adaptation planning. Having evaluated the risk that climate change poses, these agencies are ready to begin building their resilience to a range of possible climate futures.
This report highlights adaptation actions that transportation agencies around the world are already pursuing and articulates a growing set of best practices for implementing adaptation. The report also discusses strategies, examples, and best practices for evaluating the costs and benefits of adaptation. The purpose of the report is to provide transportation practitioners with a guide to the current "state of practice" in this field. Since many transit agencies have actively pursued adaptation strategies, this report also covers relevant adaptation initiatives from transit agencies.
The report is organized into seven sections. The first section provides an overview of existing research and literature on adaptation. Each of the nine studies highlighted in this section has contributed significantly to the field transportation adaptation field. Next, the report identifies common adaptation actions occurring in the disciplines of transportation asset management, long range transportation planning, design and construction, operations and maintenance, and emergency management. The fourth section highlights common best practices emerging across these adaptations, such as recognizing adaptation as a co-benefit and tracking data on extreme weather. Next, the report transitions to discussing methods of evaluating costs and benefits of adaptation options. The final sections of the report describe common barriers to adaptation, methods of overcoming those barriers, and ongoing research in the field.
Distinctions between vulnerability assessment and adaptation can be blurry. The two processes often occur in tandem, with vulnerability assessment results directly informing adaptation planning. In addition, the process of conducting a vulnerability assessment, particularly collecting data and engaging stakeholders, can increase preparedness, coordination, and communication-which can lead to adaptation. To the extent possible, this report focuses exclusively on adaptation. In this report, we consider adaptation to be any activity that reduces the vulnerability of transportation systems to future changes in climate. Common examples of adaptation include shoreline protection to reduce exposure to coastal hazards, design updates to reduce sensitivity, and building additional redundancy into the system to increase adaptive capacity.