We consider distribution systems with a single depot and many retailers each of which faces external demands for a single item that occurs at a specific deterministic demand rate. All stock enters the systems through the depot where it can be stored and then picked up and distributed to the retailers by a fleet of vehicles, combining deliveries into efficient routes. We extend earlier methods f...

This paper presents a new multi-depot combined vehicle and crew scheduling algorithm, and uses it, in conjunction with a heuristic vehicle routing algorithm, to solve the intra-city mail distribution problem faced by Australia Post. First we describe the Australia Post mail distribution problem and outline the heuristic vehicle routing algorithm used to find vehicle routes. We present a new mul...

In logistics networks involving one supply point (depot) and several geographically dispersed demand points (e.g., retail stores), delivery shortages will result if the design of delivery routes ignores random period-to-period ̄uctuations in customer demands. Delivery shortages may be costly enough for the depot to seek strategies to prevent them. A requirement for rational comparison of strate...

Vehicle Routing Problem (VRP) is a key element of many transportation systems which involve routing of fleet of vehicles from a depot to a set of customers node. It is required that these vehicles return to the depot after serving customers’ demand. This paper investigates a relaxed version of VRP, in which the number of visits to the customer is not restricted to be at most one. The relaxed ve...

The classical vehicle routing problem involves to design a set of routes for a fleet of vehicles based at one central depot that is required to service a number of geographically dispersed customers, while minimizing the total travel distance or the total distribution cost. Each route originates and terminates at the central depot and customers’ demand are known. In many practical distribution ...

We study a class of vehicle-routing problems (VRP) with simultaneous pickup and delivery (VRPSPD). In VRPSPDs, each customer may require a certain quantity of goods delivered from the depot and a quantity of goods to be picked up and returned to the depot. Besides the standard VRPSPD, we address (i) the VRPSPD with time limit (VRPSPDTL), which imposes a time limit on the routes of the transport...

The Fixed Routes Problem is a variation of the Vehicle Routing Problem in which the routes that have to be constructed will be operated unchanged for an extended period of time while the customer demands within that period will vary. If, in a delivery scenario, a vehicle cannot satisfy the demand of a customer it musts return to the depot for replenishment before continuing its route. The fixed...

this paper addresses the vehicle routing problem with delivery time cost. this problem aims to find a set of routes of minimal total costs including the travelling cost and delivery time cost, starting and ending at the depot, in such a way that each customer is visited by one vehicle given the capacity of the vehicle to satisfy a specific demand. in this research, a hybrid metaheuristic approa...

In this paper, we propose a new hybrid heuristic to solve the Location Routing Problem with capacitated depots and capacitated vehicles. The heuristic combines a Greedy Randomized Adaptive Search Procedure to determine the depot locations to be established and a Variable Neighborhood Search to optimize the vehicle routes originating at the opened depots. Furthermore, we enhance the heuristic by...

The multi-depot fleet size and mix vehicle routing problem, also known as the multi-depot routing with heterogeneous vehicles, is investigated. A mathematical formulation is given and lower as well as upper bounds are produced using a three hour execution time of CPLEX. An efficient implementation of variable neighborhood search that incorporates new features in addition to the adaptation of se...