A Capacitated Vehicle Routing Problem With Synchronized Pick-Ups and Drop-Offs: The Case of Medication Delivery and Supervision in the DR Congo

摘要

In postemergency contexts such as the Democratic Republic of Congo (DR Congo), one of the crucial challenges that rural hospitals face is maintaining a pharmacy with essential medications and supplies. There is a negative humanitarian impact when hospitals do not have medications for treatable diseases; hospitals incur financial losses when too much medication is ordered and expires. Moreover, the cost of transporting medications and providing on-site supervision to remote hospitals is an extremely expensive endeavor. Sometimes, the transportation costs can exceed the cost of the medications. Using as a case study, the province of Bandundu, in the DR Congo, we attempt to determine the feasibility (in terms of problem complexity and potential savings) of a synchronized routing problem for medication delivery and on-site supervision visits. We propose a capacitated vehicle routing problem formulation handling several novel requirements: activity-wise synchronization, precedence, and two activity frequencies. We implement a new heuristic procedure with a geospatially enabled database to solve the problem. Administrators can use a web-based tool to view the results as interactive maps. Preliminary results suggest that a synchronized solution allows rural hospitals to increase accessibility to medical services to rural populations by increasing delivery frequencies from 4 months to 1 month.