How have regional evacuation conditions changed over time? Evacuation model for alternative scenarios given the accident environment, regional environment, and social systems

The rapid evacuation in major leak accidents during hazardous chemical transportation is critical for protecting people in risk areas. An approach integrating the accident environment, regional environment, and social system is proposed to perform evacuation evaluation in such accidents. An agent-based modeling framework consisting of warning mechanisms, evacuation preparation process, as well as evacuation modes and movement process, is developed to comprehensively model the evacuation process. The regional environmental and social system data from 1964 to 2020 of Jiangsu Province in China is applied to analyze whether the changes in evacuation conditions have correspondingly affected evacuation effectiveness. A regional evacuation model simulating a real liquid chlorine leak accident during transportation in Wuzhong of Jiangsu Province is constructed to test the effectiveness and applicability of the proposed method. It is found that a 9 % change in the diffusion rate of warning messages triggered by environmental cues with the evolution of the study area settlements following the chronological changes; while the evolution of media technology allows for the rapid diffusion of warning messages and the rapid loading of a large number of individuals into the regional evacuation network; Years with faster warning diffusion have not been the most efficient ones in terms of overall evacuation; The distribution of buildings and population substantially impacts the overall evacuation effectiveness, while the former has a more significant impact. The study results can provide information for public emergency authorities to develop effective early warning resource allocation and evacuation organization plans.