Branch-and-price-and-cut for the synchronized vehicle routing problem with split delivery, proportional service time and multiple time windows

This study addresses a vehicle routing problem (VRP) in which demands are discrete, split delivery is allowed, service time is proportional to the units of delivered products, multiple time windows are provided and the demand of each customer must be delivered in only one time window (this requirement is termed synchronization constraint). We formulate this problem into a three-index vehicle-flow model and a set-covering model. Then, we propose a branch-and-price-and-cut algorithm to solve the problem. We compare our branch-and-price-and-cut algorithm with CPLEX based on 252 randomly generated instances and the computational results demonstrate the effectiveness of our algorithm.