California’s extensive transportation system, including highways, roads, railways, seaports, airports, transit, and walking and biking networks, is depended upon by millions of people and thousands of communities and businesses. Besides providing access to destinations, the transportation sector is critical to emergency response, employs a significant number of people in the state, and is essential to the state and the nation for the delivery of goods and services. Given the significance of transportation infrastructure to California’s economy and resident’s livelihoods, damage from these impacts could result in catastrophic economic loss across the state. For additional background information and discussion of climate impacts and vulnerabilities of transportation systems, visit the Background & Climate Impacts information excerpted from the Adaptation Planning Guide and explore the Topic search below.

Transportation planning requires continuous and frequent coordination across sectors and different levels of government. Furthermore, the resilience of transportation systems plays an important role in emergency management, equity, and social resilience. Examples of adaptation strategies are provided on the Adaptation Strategies page and can be found in many of the resources available by search below.

The following is excerpted from the 2020 Adaptation Planning Guide, Appendix A.

Defining the Sector

The transportation sector covers a wide range of infrastructure assets, including roadways, rail lines, bike paths, sidewalks and walkways, airports, and ports, and transportation vehicles themselves. It also includes personnel needed to construct and maintain these systems and provide transportation services. Virtually everyone in California is dependent on the transportation sector, not only for getting around, but for transporting the goods and services they use.

Roadways are perhaps the most obvious element of California’s transportation sector. They range from interstate freeways that carry tens of thousands of vehicles per hour through major urban areas to quiet neighborhood streets and remote rural roads. Designated highways are usually managed by the California Department of Transportation (Caltrans), and local governments are responsible for other roads. Roads on state and federal land, such as military bases or national parks, are typically managed by those agencies. These systems carry personal cars, heavy commercial trucks, buses, and many other vehicle types.

California’s primary rail network is another key part of the state’s transportation system. The rail system is used primarily for moving freight throughout California, and in some areas provides key public transit service. This includes regional commuter rail such as Caltrain and the Altamont Commuter Express in the Bay Area and Metrolink in the Los Angeles region; medium-distance Amtrak California trains such as the Pacific Surfliner and San Joaquin; and long-distance Amtrak trains that connect California to other states. Most of California’s primary rail system is maintained by rail lines such as Union Pacific, although some sections of track are owned by local and regional governments.

Transportation also includes public transit—both buses and rail systems—which are generally owned and operated by local transit agencies. Transit provides an essential service to many communities. In large cities, it provides a critical transportation option in densely populated areas where there is simply not enough capacity to handle all the car traffic if everyone drove instead. In both cities and less urban areas, transit (particularly buses) provides an essential service to transit-dependent populations, which may include students, low-income individuals, the elderly, the disabled, and other populations that cannot or choose not to own cars.

Airports and seaports provide more specialized transportation services for both travelers and freight and can be critical economic centers. Major airports such as Los Angeles and San Francisco International Airports are among the busiest in the United States and connect millions of travelers to destinations across the world. However, a number of smaller airports throughout California provide travel within California and to nearby states. These regional airports support public safety activities such as aerial firefighting and air medical services and provide a base for recreational flyers. Some of California’s airports are also key nodes in global air freight services.

Seaports are primarily freight centers, the largest of which receive hundreds of millions of tons of goods annually. California’s seaports are critical trade centers, handling imports and exports between the United States and other Pacific nations. However, seaports and related facilities can serve as docking areas for recreational cruises and personal water vessels. In some communities, port facilities can support ferries and other forms of water transit.

This sector also includes networks that support active transportation such as walking and biking. This includes bike lanes and sidewalks that are tied to roadways but may also include entirely separate rights-of-way such as bike paths and trails. Such networks provide access for people who are unwilling or unable to drive, including children, senior citizens, and those who do not own a personal vehicle. In some communities, these networks provide important recreational benefits, provide vital access for those commuting to and from work or school, and are contributors to the local economy.

This section focuses on transportation infrastructure and the services and economic activities that are enabled by these infrastructure systems. The fuels needed to power the transportation sector are discussed in the Energy section of this guide. Recreational and emergency management activities that rely on transportation systems are discussed in their respective sections of this guide.

Major Vulnerabilities

Climate change is likely to increase the risk of transportation networks being damaged, destroyed, or blocked by a natural hazard event, preventing movement of people and goods. This can be a minor incident, such as a tree being knocked over by high winds and falling onto a roadway, or a major event such as a bridge on an interstate freeway being destroyed by a flood. In some cases, the damage can be severe enough to block access for weeks or months. For example, a landslide in Montecito in January of 2018 closed US Route 101 in the area for about seven weeks. The previous winter, landslides along the Big Sur coast of Central California caused parts of State Route 1 to be closed for a year and a half. Notably, populations dependent on public transportation or specific transportation infrastructure may be disproportionately affected by climate impacts to that infrastructure.

Floods, landslides, severe winds, and wildfires are the major hazards to transportation systems now. These natural hazards could increase in frequency and severity over time with climate change. In the long term, sea level rise could inundate transportation assets along coastal areas, causing them to close temporarily or permanently. Extreme heat can also be problematic for transportation systems, melting the asphalt on roadways, buckling rail lines, requiring vehicles to travel at slower speeds, or closing roads or rail lines.

In some cases, a closed section of a transportation network is the only way in or out of an area, which can create significant hardships until the network is reopened and creates greater risks during evacuation and emergency response situations. While this is often thought of as a rural issue, it can also affect parts of more urbanized areas (for example, some residential areas in the canyons of the Los Angeles region).

Some transportation activities depend on a single piece of infrastructure, such as a rail line or ferry terminal, and damage to these facilities can cause a complete shutdown of the service. Even if alternative routes or services are available, the closure often causes significant congestion as the people and goods that normally traveled the closed route are forced onto other parts of the transportation network. In addition to increasing travel times, this can place increased stress on alternative routes, which will require more maintenance. Damage to pieces of transportation infrastructure that help to move goods can cause widespread disruptions to supply chains, which may have major economic impacts that affect international trade as well as the local economy.

Transportation networks also rely on vehicles such as cars and trucks, rail trains, ships, and aircraft. Damage to these vehicles affects transportation services, even if the underlying network is unharmed. This is mostly a concern for economic activities and community services that depend on a vehicle fleet, such as vehicles used for public transit or goods delivery. These fleets are usually stored in centralized yards when not in use, creating the risk that a climate-related event such as a wildfire or flood could damage or destroy most or all of the vehicles. This can cause long-term service disruption, especially if the vehicles are custom built, such as rail trains.

Extreme heat can create problems for the transportation sector even without doing damage to physical systems. During very high temperatures, electrical equipment operates at reduced effectiveness, which can increase the risk of failure for vehicles that are powered by electricity. Similarly, power outages are more likely during extreme heat events, affecting electrically powered rail transportation systems. In particularly extreme heat events, air becomes less dense, sometimes to the point that it cannot provide enough lift for some aircraft to take off.

Climate hazards
Adaptation Strategy
Factors to Consider
Sector overlap
Responsible Agencies
Examples & Sources
Coastal storms, Extreme heat, Flooding, Landslides, Severe storms, Sea level rise, Wildfire

Strategy TRANS-1: Update maintenance protocols to incorporate climate vulnerabilities.

The increase in intensity and frequency of climate-related hazards and other effects, such as flooding and extreme heat, can affect day-to day operations and maintenance of transportation infrastructure, including roadways, railways, airports, and active transportation routes. Updating maintenance system to adapt to climate change effects can involve shifting outdoor physical labor hours to earlier in the morning during extreme heat days. Transportation agencies might also increase stormwater drainage infrastructure maintenance to ensure that when storms arise, there is sufficient drainage capacity to convey any surface-level flooding.

Local governments should not only consider roadways, but also look at railways, airports, seaports, transit, and active transportation systems when updating maintenance protocols. Railway systems can move large amounts of freight, including essential goods, in addition to an important element of moving people during commuting hours in some areas of the state. Maintenance of active transportation corridors could include installing green infrastructure to increase drainage capacity, or planting trees to increase shade cover. Plans, Regulations, and Policy Development Emergency Management Public Health Cities and Counties Transportation Agencies Councils/Associations of Governments  
Coastal storms, Extreme heat, Flooding, Landslides, Severe storms, Sea level rise, Wildfire

Strategy TRANS-2: Coordinate with both community members, transportation agencies, and private entities to identify local and regional transportation, transit, and active transportation corridors that are at-risk from climate change effects.

Transportation corridors, such as evacuation routes, transit routes, regional bike paths, and major commuting routes may be impacted by climate change effects. These corridors can include hundreds of miles of roadways, rail, or multiple airports, which can create difficulties in identifying at-risk areas on those routes. However, throughout coordination with community members, transportation agencies, Caltrans, and private entities, such as Union Pacific Railroad, local governments can locate specific areas that may be at the greatest risk to damage or destruction from climate-related effects.

An important factor to consider when coordinating with multiple stakeholder is the method of communication. Formal meetings and roundtables may work for transportation agencies and private entities, but workshops or hosting community events may work better for engaging community members. Community members typically have local knowledge of their neighborhood, which can help in identifying acute problems at a local street scale. When conducting outreach to community members, it is essential to work with community residents and groups to determine appropriate and culturally relevant communication strategies to reach all sectors of the population. Education, Outreach, Coordination Public Health Cities and Counties Transportation Agencies Councils/Associations of Governments  
Coastal storms, Extreme heat, Flooding, Landslides, Severe storms, Sea level rise, Wildfire

Strategy TRANS-3: Use the best available science and resilient design features in transportation infrastructure to improve resiliency to extreme climate events.

Local governments can take a number of steps to increase transportation resiliency of roadways, railways, airports, and seaports. For example, special sealants and other materials on roadways can help prevent roadways from softening during extreme heat. Other resilient design features include choosing appropriate roadway materials for wildfire prone areas, treating rail lines to be heat-resistant, and incorporating expansion joints into rails that reduce the risk of damage during high temperatures. Roads and railways can be built on foundations that are resistant to washouts from flood events. For airports, infrastructure reinforcement, stormwater improvements and drainage upgrades, and pumping and water storage facilities can be installed to increase resiliency to flooding and wave action by coastal storms. In some cases, increasing resiliency may involve updating design standards or replacing existing infrastructure to account for the changing conditions.

When deciding which resilient design features to use, it is important to consider where the vulnerable infrastructure is located (mountains/hills, low-lying valleys, coastal areas, desert). This can help determine whether design features should include hardening for landslides and wildfires, additional stormwater drainage for coastal and inland flooding, or replacement of resources with heat-resistant materials. Resilient design can also include increasing levee height, raising or relocating roads and railways, and installation of tidal gates in coastal areas. It is also essential to coordination with transportation agencies, Caltrans, airports, and railway operators to ensure that resilient design features are consistent between different entities. Additionally, local governments should consider these features for alternative transportation routes, such as walking and biking paths. Capital Improvement & Infrastructure Projects Emergency Management Land Use and Community Development Ocean and Coast Cities and Counties Transportation Agencies Councils/Associations of Governments  
Coastal storms, Flooding, Landslides, Severe storms, Wildfire

Strategy TRANS-4: Coordinate with regional transportation agencies to ensure redundancy of critical transportation routes to allow for continued access and movement in the event of an emergency.

Transportation routes, which often double as evacuation routes, are at risk of shutdowns during a climate-driven emergency. If essential transportation and evacuation routes are closed or blocked due to hazardous conditions or major traffic delays, evacuations may not be possible. Critical services, such as healthcare and emergency response may not be able to properly carry out their functions, and economic activities may slow or stop. Creating redundancies in transportation systems can lessen the potential severe effects of a shutdown on critical routes.

Local governments should study changes along designated evacuation routes associated with more frequent and severe wildfire, coastal and inland flooding, landslides, and severe storm events. Important nodes along evacuation routes include bridges and segments that are located above streambeds or waterways. This study can ensure that high risk areas are hardened, and infrastructure remains operational during emergencies to ensure there are means to conduce community-scale evacuations. Education, Outreach, Coordination Capital Improvements & Infrastructure Projects Emergency Management Cities and Counties Transportation Agencies Councils/Associations of Governments  
Coastal storms, Flooding, Landslides, Severe storms, Wildfire

Strategy TRANS-5: Coordinate with regional transit providers to identify alternative routes and stops if normal infrastructure is damaged or closed as a result of extreme events.

Disruption to transit services can deprive some community members of their only means of travel to school, work, or services. To help ensure that transit services can continue to operate during and after extreme events, local governments should collaborate with regional transit providers, transportation agencies, and private transit providers to identify alternative routes and tops in the event that they can no longer use normal infrastructure. Alternatives should be located near normal routes and stops with clear communication to reduce disruptions to transit riders.

When creating alternative transit routes or stops, local governments should consider to communication methods used to convey the changes in service. Methods could include signage and flyers, television, radio, print media, and digital services. Communication should be presented in a culturally relevant manor in languages that are representative of the local demographic. Education, Outreach, Coordination Operational Ocean and Coast Emergency Management Public Health Cities and Counties Transportation Agencies   Resilient IE (2020)
Air quality, Extreme heat

Strategy TRANS-6: Collaborate with public works departments and regional transit providers to increase shading and heat-mitigating materials on pedestrian walkways and transit stops.

Adequate shade on sidewalks and transit stops is essential for community members who walk or use public transit to get to their destinations. To increase the comfort of pedestrians and bicyclists on hot days, local governments can work with local jurisdictions to install pavement with high albedo, which absorbs less heat and contributes less to the urban heat island effect. Heat-reflective pavement can be applied either by replacing existing surfaces or by coating surfaces with a highly reflective coating. Local governments can also encourage tree planting programs along walkways to provide shade, particularly in communities that have little shade. This could help reduce heat and improve local air quality, as well as incentivize outdoor activity.

Local governments should prioritize areas that have few trees or lack shade covers when implementing heat-mitigation projects. When increasing shade at transit stops and walking or biking paths, local governments should also consider installing green infrastructure, which can both increase shade and prevent flooding in low-lying areas. Programmatic Education, Outreach, Coordination Public Health Cities and Counties Transportation Agencies  

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