The humanitarian vehicle routing problem with non-routineness of trips

In this study, we address a pressing yet underexplored problem in humanitarian logistics (HLs), which is enhancing the safety and security of humanitarian personnel in conflict zones, through the introduction of non-routineness of trips in vehicle routing models. This research is critically justified, as evidenced by the alarming statistics from 2020, where over 100 road ambushes were reported, affecting over 200 humanitarian workers through kidnappings, injuries, and fatalities. Moving beyond traditional approaches that primarily focus on increasing convoy sizes or incorporating ambush probabilities, our research poses a pivotal question: How can existing knowledge from security journals and manuals be effectively leveraged to address this problem? In response, we have developed a groundbreaking vehicle routing model that ensures variability in routes and travel times, significantly reducing the predictability of humanitarian convoys and enhancing their security. Our approach also integrates additional security measures, including avoiding night travel and implementing convoy camping strategies, to further mitigate risks. A central innovation of our study is the creation of a first-of-its-kind index, designed to quantify the routineness of trips – a critical yet previously overlooked metric in HLs. The efficacy of our model is demonstrated through a comprehensive case study in South Sudan, a region afflicted by ongoing civil unrest, underscoring the real-world applicability and urgency of our research. Additionally, we provide an approximate closed-form solution for the aid allocation subproblem, optimizing for both fairness and effectiveness. This research marks a significant leap forward in logistics optimization, especially within HLs in conflict zones, addressing a vital gap in the literature and offering innovative perspectives and practical solutions to complex security problems faced by humanitarian logisticians.