Time Varying Route Optimization of Hazardous Materials Transportation Considering Risk Equity

Transportation of hazardous chemicals is a critical component of chemical logistics, with unique properties such as flammability, explosiveness, and corrosiveness posing significant risks of catastrophic accidents. While the current literature has focused on reducing the overall risk within hazardous materials transportation systems, it has paid less attention to the equitable distribution of risks across regions from a public health perspective. Furthermore, there is a scarcity of research on the optimization of hazardous material transportation routes that consider risk equity in the context of fluctuating population densities and wind speeds. This article considers the impact area of hazardous chemical accidents under various wind speed conditions. It then establishes a time-varying risk assessment function that considers changes in population density over time. The Gini coefficient is employed to quantify the disparity in risks among different routes. Building on this foundation, we propose a novel time-varying route optimization model for hazardous materials transportation that incorporates risk equity considerations. Secondly, we design an improved genetic algorithm based on the ε-constraint method to solve the proposed model efficiently. Finally, the research methodology is applied to a realistic transportation network in Shanghai, providing a case study that illustrates the application of the model. The study also examines the temporal distribution of risk equity, offering practical and feasible insights into the dynamics of risk allocation in practical scenarios.