The problem of simultaneous routing of road cleaning and relief vehicles for an effective planning method after natural disaster

Natural disasters are large-scale natural events that are unpredictable and cause physical, economic and social losses. Disasters leave residues called debris, whose content can change. The debris can block roads and hinder transportation in the disaster area. However, it is necessary to reach the disaster area as quickly as possible after the disaster. Thus, the quality of life will be increased by delivering aid to the disaster victims. In this study, a problem that deals with the processes of opening the roads closed due to debris in the disaster area and delivering the relief materials to the needed nodes as quickly as possible in a synchronized manner is discussed. It is assumed that there is one road cleaning vehicle and more than one aid delivery vehicle within the scope of the problem. A mixed integer linear programming model has been developed to solve the problem. Since the developed model could not find a solution in an acceptable time for realistic sized problems, a heuristic algorithm was developed to solve the problem. Nodes that are important to reach such as hospitals and schools in the disaster area are considered as critical nodes. Within the scope of the model, the fastest routes for the delivery of relief materials to critical nodes are determined, and if there is a road closed due to debris on the route, the road in question is cleared of debris. Vehicles start their tours simultaneously and perform their tasks synchronously. Relief delivery vehicles cannot use that road until the road clearing vehicle completely clears a road of debris. The cleaning time of the road affects the arrival time of the relief materials. In the context of testing the performance of the developed mixed integer linear programming model and the heuristic algorithm two different data sets were used. In addition, solutions with different road blockage rates and variable number of relief vehicles were considered in order to understand the effect of road closure rate and number of relief delivery vehicles on the solutions developed. In addition, the effect of different iteration numbers on the performance of the heuristic algorithm is also analyzed. The main contribution of this study to the literature is the synchronization of road cleaning and relief material distribution processes. Due to the limited resources in the literature in the subject area, it is considered that the developed model can be beneficial.