As part of an effort to identify how climate change might impact the State Highway System, Caltrans has released three new Climate Change Vulnerability Assessments that focus on the risks posed to Southern California’s transportation system by wildfires, extreme temperatures and precipitation, rising sea levels, and coastal-bluff erosion.

“Climate change is an immediate and escalating threat to California and its transportation system, and Caltrans is being proactive. We are looking at where the state highway system is vulnerable, so we can address issues moving forward,” said Bob Franzoia, Caltrans Acting Director.

The new reports cover Imperial, Los Angeles, Riverside, San Bernardino, San Diego and Ventura counties and include an interactive mapping application that shows where and how climate change is expected to have an impact.

Caltrans is committed to ensuring the long-term health of the State Highway System and to working with partners to safeguard California’s vast transportation system. These new vulnerability assessments will help guide the department toward planning and investment strategies that lessen the impacts of climate change and save taxpayers money.

Caltrans will share the reports’ data with local, regional, state and federal agencies. Together, the partners will work toward establishing a more resilient transportation system and responding to the need for actions to adapt to the changing climate.

Among the factors that Caltrans must consider when planning for climate change is the role of the State Highway System in Evacuation Planning when a disaster strikes. Caltrans notes that the State Highway System is the backbone of most county-level evacuation plans and often provides the only high-capacity evacuation routes from rural communities. In addition, state highways also serve as the main access routes for emergency responders, and may serve as a physical line of defense such as a firebreak or an embankment against floodwaters. As climate-related disasters become more frequent and more severe, Caltrans says this aspect of State Highway System usage will assume a greater importance that may need to be reflected in design. The agency’s upcoming studies of climate change adaptation measures will take these factors into account to identify measures appropriate to each situation.

The reports also identify recent extreme climate events in each district and show that, in recent years, Southern California has been beset by destructive and deadly wildfires and is experiencing record heat waves, comparatively wet winters and more frequent mudslides. These general climate trends are expected to continue in California and the rest of the West region:

  • More-severe droughts, less snowpack, and changes in water availability.
  • Rising sea levels, more-severe storm impacts, and coastal erosion.
  • Increased temperatures and more-frequent, longer heat waves.
  • Longer and more-severe wildfire seasons.

These new SoCal reports add to the list of similar reports being prepared for each of Caltrans’ 12 districts across the state. Upon completion of all 12 assessments, Caltrans will develop adaptation reports for each region that outline how climate change will be fully integrated into future transportation decisions.

Source: Caltrans