Emergency material distribution center site selection and route planning under consideration of time equity constraint

The COVID-19 pandemic has underscored the catastrophic challenges posed by large-scale infectious disease outbreaks. Beyond overwhelming public health systems and straining economic resources, such crises disrupt daily life and erode societal stability. In these contexts, the rapid allocation of limited emergency supplies becomes a critical component of response efforts. However, the perceived fairness of service delivery times significantly influences public satisfaction and psychological well-being, particularly in prolonged lockdown scenarios where pandemic fatigue becomes pervasive. Despite its importance, traditional logistics research often overlooks the equity of time allocation and the psychological toll of uneven distribution during emergencies. To address these challenges, this study develops a bi-objective optimization model aimed at minimizing both the emergency logistics system’s total cost and the effect of time loss comparison among demand points. It is solved using a non-dominated sorting genetic algorithm based on the elite strategy, and the arithmetic example is analyzed using a combination of real data and simulation data. Facing the COVID-19 pandemic in 2022, Changchun’s city-wide lockdown led to people’s pandemic fatigue. In this study, we propose a bi-objective model considering temporal equity and logistics cost, contrasting a single-objective model focused on logistics cost. Results show that considering temporal equity reduces the loss comparison effect to 57,583, increasing total logistics cost to 140,000 yuan;excluding temporal equity, the effect is 123,010 with a cost of 120,000 yuan. The bi-objective model’s cost rises 13.76%, but the loss comparison effect drops 53.19%, suggesting greater temporal benefits at a lower cost. This paper ideally balances temporal equity and economic marginal benefit, making emergency supply distribution more humane and equitable, showcasing the model’s effectiveness and social responsibility. Not applicable.