We consider the capacitated vehicle routing problem (VRP): a fixed fleet of delivery vehicles of uniform capacity must service at minimal transit cost from a common depot known customer demand for a single commodity. This problem is modeled as a side-constrained traveling salesman problem (TSP). Among the additional constraints are the vehicle capacity restrictions, analogous to TSP subtour eli...

Centre de recherche sur les transports and D epartement d'informatique et de recherche op erationnelle, Abstract: Dynamic vehicle routing and dispatching refers to a wide range of problems where information on the problem is revealed to the decision maker concurrently with the determination of the solution. These problems have recently emerged as an active area of research due to recent technol...

Heuristic programming algorithms frequently address large problems and require manipulation and operation on massive data sets. The algorithms can be improved by using efficient data structures. With this in mind, we consider heuristic algorithms for vehicle routing, comparing techniques of Clarke and Wright, Gillett and Miller, and Tyagi, and presenting modifications and extensions which permi...

When delivering items to a set of destinations, one can save time and cost by passing a subset to a sub-contractor at any point en route. We consider a model where a set of items are initially loaded in one vehicle and should be distributed before a given deadline ∆. In addition to travel time and time for deliveries, we assume that there is a fixed delay for handing over an item from one vehic...

The Traveling Salesman Problem (TSP) is maybe the archetypical problem in combinatorial optimization. This problem and its generalizations, vehicle routing problems, have been studied for more than thirty years; two entire monographs are devoted to the subject [34, 26]. Since the TSP is NP-hard, polynomial-time approximation algorithms are usually studied. However, usually the approaches to the...

We introduce a package service model where trucks as well as drones can deliver packages. Drones can travel on trucks or fly; but while flying, drones can only carry one package at a time and have to return to a truck to charge after each delivery. We present a heuristic algorithm to solve the problem of finding a good schedule for all drones and trucks. The algorithm is based on two nested loc...

Multi-echelon distribution systems are quite common in supply-chain and logistic systems. They are used by public administrations in their transportation and traffic planning strategies as well as by companies to model their distribution systems. In the literature, most of the studies address issues related to the movement of flows throughout the system from their origins to their final destina...

Most algorithms for solving vehicle routing problems use the criterion of minimizing total travel time in forming their routes. As illustrated in the paper, even in the case of a homogeneous fleet, solutions using other criteria may be preferred to the solution generated by minimizing total travel time. This situation becomes more pronounced when considering a vehicle routing problem where the ...

A key element of many distribution systems is the routing and scheduling of vehicles through a set of nodes requiring service. The Vehicle Routing Problem (VRP) can be defined as a problem of finding the optimal routes of delivery or collection from one or several depots to a number of cities or customers, while satisfying some constraints. In many practical situations, however, the vehicle is ...