Extreme events in 2021 cost the United States approximately $145 billion United States Dollars (USD), with the western wildfires accounting for 8% of those costs. California’s wildfire impacts in 2018 totaled 148.5 billion USD including capital losses, health costs, and indirect losses such as disruptions to supply chains. Wildfires have also been more devastating in California during the last decade. Between 2017 to 2019, there were about 11 large-scale wildfires requiring the evacuation of at least ten thousand people each, resulting in more than one million people ordered to evacuate in three years, mostly from wildland-urban interface (WUI) areas. Because a significant number of people live in WUI areas and the increasing frequency of climate-driven wildfires, impacts are expected to increase. Different agencies are developing preparedness, mitigation, and adaptation plans, but for short or no-notice fast-moving wildfire events, evacuation is critical. Evacuation processes usually rely on the road network and one of the characteristics of evacuation scenarios is the heavy bottleneck and slow traffic speed due to the high volume of vehicles that are using a limited and capacitated set of roads.
The project will help centralize and assess evacuation routes, and assess their capacity for evacuation. It will help inform infrastructure investment priority decisions, as it will identify the road segments with the largest impact on the evacuation route/network performance. The research products will include a GIS database of safety elements from local jurisdictions, an evaluation of the degree to which the State Highway System (SHS) and bus and rail lines contribute to the evacuation system, and a screening of the SHS to identify the most critical parts of the network and areas of potential shortfall or lack of evacuation infrastructure.
At the state level, this project will identify the alignment and gaps of local plans and state transportation infrastructure to vulnerable communities as documented in CalEnviroScreen and the US Census. The case studies of proposed evacuation plans with actual evacuation events will be performed on 2–5 case locations. The research will provide a calculation of the performance of the evacuation routes, the road network, and the performance of the evacuation routes for different segments of the population. Finally, the team will discuss the recommendations on how to achieve efficiencies and promote safe evacuation routes, present the final results in public and internal meetings, and the team will submit a journal article that presents the methodology for peer review.