Evacuation Route Analytics

Risk Reduction Category

Modeling and Simulation

Technology Description

Evacuation route planning is a complex and multi-variable challenge. Issues arising in California due to recent wildfire events have identified the need for quantitative evaluations concerning evacuation routes and travel times. Project-level California Environmental Quality Act (CEQA) analyses should include these. Recent court rulings have underscored the need for the CEQA to more fully consider the potential effects on evacuation routes of projects located in high wildfire-prone areas.

The range of evacuation conditions including time of day, fire behavior, route options, automobile availability, and shelter locations greatly complicate forecasting evacuation trip demands. For instance, at night, nearly 100% of population may be at home whereas at 5 pm, people returning home from work would be mixing with the traffic trying to escape the emergency. Further complications include multiple cars and drivers per household that might add even more vehicles on the road as people try to save as many vehicles as possible in a crisis.

Planning scenarios should consider historical evidence from past events, and expert opinions (also based on evidence) from local fire and law enforcement personnel. Another consideration involves “the State of the Practice” that may inform analysis methods. For instance, travel demand data (whatever its source) along with Highway Capacity Manual (HCM) methodologies might be used within a simulation model to estimate delays within the transportation network.

However, travel demand models during non-emergency situations have been found to underestimate travel times in often-congested corridors by 50% to 100%. This may be even worse during an evacuation event. Dynamic Traffic Assignment (DTA) models may use uncongested speed and capacity data coming from a local travel demand model along with how queues build in the travel corridor over time along with evacuation demand to generate evacuation time estimates. The traffic operations analysis should fit the congestion context [1].

Geolocation services, relying on the Global Positioning System (GPS), and Geographic Information Systems (GIS) may be instrumental in identifying potential escape routes and routes to avoid. Smartphones, vehicles, and wearable devices may access this information [4]. Thus, Real-time location tracking, proactive communication, and situational awareness may be available to emergency officials and citizens alike.

Technical Readiness (Commercial Availability)

Fehr & Peers has developed a tool called EVAC+ to work out an emergency evacuation capacity assessment [8]. This tool addresses complex emergency evacuation challenges by interfacing with regional travel demand models. It considers inputs such as number of people and vehicles per household, the distribution of evacuation trips during the event, and a dynamic traffic assignment (DTA) model to estimate travel times. “Our understanding of traffic operations and travel demand forecasting provides a unique platform to assist in evaluating emergency evacuation scenarios as part of this effort. Ultimately, our goal is to provide meaningful information to our clients that will benefit the community during an evacuation event.” [8]

The Federal Highway Administration has produced a series of tools/articles on the subject of Using Highways During Evacuation Operations for Events with Advance Notice [5]. Examples are Evacuation Traffic Information System (ETIS), and Evacuation Travel Demand Forecasting System among several others. ETIS is a web-based application that.

Plume Modeling Tools predict the direction and speed that a plume may travel from its release location. The plume may be created by fire, radiological or chemical release, or other causes of traveling airborne contaminants. Many plume models exist, most being specific to the type of event that caused the plume. These models accept site-specific data such as wind speed, direction, and other factors. [5]

Implementations / Deployments

Innovations as of Mid 2023

Sandia National Lab is taking into account an additional layer of complexity to planning for disaster evacuations by considering a new and growing segment of drivers: those owning electric vehicles.

The study identifies the impacts of vehicle charging load on the grid during evacuation periods as well as the impact of limited range on passage through planned routes. The study discusses optimizing infrastructure related to EV charging to maximize charging capability and to minimize evacuation time. According to Sandia’s website, the impacts of this project are: [7]

  • Impacts analyses of EV penetration on the power grid during evacuation
  • Solutions to satisfy the unserved EV load during evacuations
  • Multi-objective optimization models to maximize evacuation efficiency and utilization of EV supporting infrastructure.

Potential Enrichment Work Opportunity

References

[1] Fehr & Peers, “Evacuation Planning & Resilience” https://www.fehrandpeers.com/evacuation-travel-time-analysis\

[4] Utilities One: https://utilitiesone.com/geolocation-solutions-empowering-community-specific-emergency-evacuations

[5] https://ops.fhwa.dot.gov/publications/evac_primer/23_monitoring.htm

[7] https://energy.sandia.gov/programs/electric-grid/wildfire-electric-grid-resilience/

[8] https://www.fehrandpeers.com/wp-content/uploads/2022/08/Evacuation-Planning-Resiliency-Packet.pdf