عنوان مقاله [English]
The vehicle routing problem (VRP) is one of the most well-known optimization problems. It has been the focus of extensive research on transportation systems planning in recent decades. The present aims to investigate the problem of routing vehicles from the pharmacy for the delivery of drugs at patients' homes. The problem of delivery of drugs required by patients is accompanied by a series of operational limitations. It is assumed that each patient receives drugs through a vehicle, and also drugs must reach the patients’ homes before a certain time. To balance the workload of drivers, the maximum number of homes that each vehicle can go to deliver medicines is predetermined. The presented model determines the number of vehicles, the routes of the vehicles and also the time at which drugs are delivered at each patient’ home. To solve the proposed model, in addition to GAMS optimization software, a genetic algorithm is proposed for large-scale instances. The computational results demonstrate that the proposed model can be used to make optimal decisions on the distribution of drugs from pharmacies to patients' homes.