A Humanitarian Logistics Model Integrating Heterogeneous Vehicle Routing, Time-Based Transportation Mode Switching, and Overtime Penalties for Disaster Pharmaceutical Logistics
Year: 2026
Type: article
Abstract: Earthquakes are sudden, unpredictable disasters that disrupt transportation infrastructure while generating surges in medical demand, posing critical challenges to last-mile pharmaceutical logistics. Existing humanitarian logistics models rarely integrate heterogeneous transportation modes, time-dependent mode switching, and operational constraints within a unified framework. This study develops a cost-optimised pharmaceutical distribution model based on a heterogeneous vehicle routing problem (VRP) that incorporates post-disaster infrastructure disruption, time-based mode switching, and overtime penalties. Using the 2022 Cianjur Earthquake (Indonesia) as a case study, three strategies are evaluated: a baseline, a Mixed-Integer Linear Programming (MILP) optimisation model, and a two-phase heuristic combining a savings algorithm with local search. The model distributes 550 pharmaceutical packages to 47 primary healthcare centres (PHCs) under a 480-minute daily operating constraint. The MILP model reduces total cost by 5.89% relative to the baseline (IDR 430,052,945), while the two-phase heuristic achieves the lowest cost (IDR 391,811,960; ?8.89%) at a 100% service level. Sensitivity analysis indicates a four-day emergency duration gives the most cost-efficient transition from fast-response modes to consolidated truck distribution. The findings provide a practical optimisation framework and decision-support insights for efficiency, responsiveness, and resilience in disaster pharmaceutical logistics.
DOI: 10.31387/oscm0670543
Language: English
Domain: Social Sciences
Open Access status: diamond
OpenAlex ID: W7222890985