A reliable, safe, and efficient U.S. transportation system is at risk from increases in heavy precipitation, coastal flooding, heat, wildfires, and other extreme events, as well as changes to average temperature. While transportation is vulnerable to the impacts of climate change, it also contributes significantly to the causes of climate change.

Source: Chapter 12 of the Fourth National Climate Assessment








The transportation sector consists of a vast, interconnected system of assets and derived services, but a changing climate undermines the system’s ability to perform reliably, safely, and efficiently. Heavy precipitation, coastal flooding, heat, and changes in average precipitation and temperature impact individual assets across all modes. These impacts threaten the performance (defined by national goals listed in 23 U.S.C. § 150) of the entire network, with critical ramifications for safety, environmental sustainability, economic vitality and mobility, congestion, and system reliability, particularly for vulnerable populations and urban infrastructure. Fortunately, transportation professionals have made progress understanding and managing risks, though barriers persist (Source:Chapter 12 of the Fourth National Climate Assessment).

Heavy precipitation, coastal flooding, heat, and changes in average precipitation and temperature affect assets (such as roads and bridges) across all modes of transportation. The figure shows major climate-related hazards and the transportation assets impacted {Source: Figure provided by Jennifer M. Jacobs. Photo credits from left to right: JAXPORT, Meredith Fordham Hughes; Oregon Department of Transportation; NPS – Mississippi National River and Recreation Area; Flickr user Tom Driggers; Flickr user Mike Mozart ; Flickr user Jeff Turner ; Flickr user William Garrett. [CC BY-NC 2.0] [CC BY 2.0] }.


The United States relies on diverse modes of transportation:

  • The road system comprises approximately four million miles of mostly publicly owned roads and over 600,000 bridges. These assets serve more than 230 million personal automobiles and light trucks, 10 million heavy trucks, and more than 70,000 transit buses.
  • The rail system comprises 140,000 miles of mostly privately owned rail track, with most freight rail service provided by seven privately owned rail companies. Passenger rail service is provided by the federally owned Amtrak and a range of state and local rail service agencies.
  • Public transit agencies maintain some 12,000 miles of track, supporting about 20,000 rail vehicles. They also operate about 70,000 buses, 188 ferry boats, and more than 80,000 vans and demand-response vehicles.
  • A network of privately owned pipelines convey fuels and fuel products across the country, including 300,000 miles of pipeline for natural gas, 50,000 miles of pipeline for crude oil, and 75,000 miles of pipeline for petroleum products.
  • Coastal and inland waterways, largely used for freight, include a system of mostly federally operated locks and canals. These enable access to ports with diverse ownership for a mostly private fleet of 31,500 barges, 200 ocean-going U.S. flagships, and 9,000 other vessels.
  • Air transportation is facilitated by the National Airspace System, which is operated by the federal government. The system includes a network of routes, radar systems, and air traffic control centers used by 7,500 mostly private, U.S.-registered commercial airliners, foreign airliners, and more than 200,000 general aviation aircraft.

Supply chains represent a shipper’s view of the freight transportation network. The chain includes all the elements involved in transporting raw materials to processing locations and fabrication facilities, as well as those that bring finished products to vendors and final customers. With the continued development of global trade among countries, the supply chains of materials such as coffee from Africa or coconut oil from the Philippines span the whole world. As materials move from their source to processing and/or manufacturing facilities, and then to retailers and end users, interruptions in any portion of the chain can increase costs and inconvenience customers. Some supply chains are only important to the makers and users of particular products. Other chains—for example, those that supply fuel and food—are of importance to suppliers, consumers, and the economy (Source: U.S. Climate Resilience Toolkit).

  1. How will climate trends affect transportation systems and their future design?
  2. What parts of the transportation system will be most vulnerable to climate change?
  3. How can climate information be most effectively translated for use by transportation practitioners?
  4. How will climate adaptation need to be integrated into existing transportation management systems?
  5. What capacity currently exists for adaption?
  6. What tools and datasets apply broadly to different transportation users and sectors?
  7. What information needs to be local and regional specific?
  8. What information and resources are necessary to enable transportation officials to effectively adapt transportation systems to climate change stresses and extreme weather events?
  9. How will transportation demands be impacted by climate change?
  10. Transportation system networks used as evacuation. What infrastructure changes will be needed to ensure viability of evacuation routes in coastal areas?
  11. The use of public transportation during high/low temperatures, precipitation, and extreme weather.
  12. What are the thresholds for transportation decisions in a changing climate? What would “climate ready” standards look like for each sector and discipline?

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