Routes Consistency And Workload Balance In Vehicle Routing Problem

High-quality transportation service is critical for logistics delivery companies to improve customer satisfaction.This paper proposes a strategy of routes consistency to provide a new method for logistics delivery companies making routes plans and vehicle deployment schedules.The routes consistency strategy aims to limit the maximum number of different routes that each driver can operate in the planning period on the premise of allowing to visit the customers without demands,thus increase the routes familiarity of drivers and improve the service quality.The actual routes planning based on routes consistency means the route planning that only visits the customers with demands every day in the planning period.Although it destroys the driver's familiarity with routes to some extent,it affects the drivers' consistency and arrival time consistency.Consequently,this paper studies the periodic vehicle routing problem with routes consistency.The goal is to minimize the total working time of drivers which includes driving time and service time.To solve this problem,a mixed integer linear programming model is established and solved by the existing mixed integer linear programming solver CPLEX.For solving large-scale instances,this paper develops a large neighborhood search algorithm with tabu search.The algorithm includes the steps of initialization by Clarke-Wright algorithm,neighborhood search by four neighborhood search operators and improvement by tabu search algorithm.Finally,this paper uses the benchmark data of the consistency vehicle routing problem,and conducts a series of small,medium and large-scale numerical experiments to verify the effectiveness of the proposed model and algorithm.The effect of routes consistency on the driver consistency and arrival time consistency is also analyzed.In addition,this paper further studies the periodic vehicle routing problem with workload balance.The realization of workload balance is to control the maximum workload differential among drivers within a small range,thus ensure that drivers' working time in the period is at the same level.For solving this problem,a mathematic model and the local branch-based method are proposed.Finally,the results comparison of CPLEX and the local branch-based method and the effect of workload balance on total working time are analyzed by numerical experiments.