A concise guide to existing and emerging vehicle routing problem variants

Vehicle routing problems have been the focus of extensive research over the past sixty years, driven by their economic importance and their theoretical interest. The diversity of applications has motivated the study of a myriad of problem variants with different attributes. In this article, we provide a concise overview of existing and emerging problem variants. Models are typically refined along three lines: considering more relevant objectives and performance metrics, integrating vehicle routing evaluations with other tactical decisions, and capturing fine-grained yet essential aspects of modern supply chains. We organize the main problem attributes within this structured framework. We discuss recent research directions and pinpoint current shortcomings, recent successes, and emerging challenges.

A concise guide to existing and emerging vehicle routing problem variants.

As of April 2007, the European Union has new regulations concerning driver working hours. These rules force the placement of breaks and rests into vehicle routes when consecutive driving or working time exceeds certain limits. This paper proposes a large neighborhood search method for the vehicle routing problem with time windows and driver regulations. In this method, neighborhoods are explored using a column generation heuristic that relies on a tabu search algorithm for generating new columns (routes). Checking route feasibility after inserting a customer into a route in the tabu search algorithm is not an easy task. To do so, we model all feasibility rules as resource constraints, develop a label-setting algorithm to perform this check, and show how it can be used efficiently to validate multiple customer insertions into a given existing route. We test the overall solution method on modified Solomon instances and report computational results that clearly show the efficiency of our method compared to two other existing heuristics.

European Driver Rules in Vehicle Routing with Time Windows

The alignment of sales territories represents a major problem in salesforce management with considerable impact on profit. The common approach to this alignment is the balancing approach, which establishes territories balanced as well as possible with respect to one or more attributes such as potential or work-load. Unfortunately, this approach does not necessarily guarantee an alignment that maximizes profit. As a consequence, it does not allow evaluation of the profit implications of any alignment proposal in comparison with the existing one. Because of this, several authors have already proposed nonlinear integer optimization models that attempt to directly maximize profit by simultaneously considering the problems of selling time allocation across accounts as well as the assignment of accounts to territories. However, these models proved to be too large to be mathematically solvable, such that the authors have either simplified the problem or proposed application of heuristic solution procedures. The latter is based on the principle of equating the marginal profit of time for each salesperson. We show here that an optimal solution does not possess the property of equal marginal profits of time. We thus propose a new approach, COSTA, for the derivation of contribution optimizing sales territory alignments. COSTA is based on sales response functions at the level of sales coverage units incorporating selling time as independent variable and using a new concept designed to take travel times into account. This makes it possible to simultaneously solve the allocation and assignment problem. Furthermore, COSTA provides the structure for evaluating the effects on profit of different salesforce sizes and different locations of the salespersons. The suitability of COSTA for practical problems is supported by a real-world application in which COSTA improved an existing territory alignment by 5.8% in terms of profit contribution.

COSTA: Contribution optimizing sales territory alignment

A review of vehicle routing with simultaneous pickup and delivery

Over the past two decades, equity aspects have been considered in a growing number of models and methods for vehicle routing problems (VRPs). Equity concerns most often relate to fairly allocating workloads and to balancing the utilization of resources, and many practical applications have been reported in the literature. However, there has been only limited discussion about how workload equity should be modeled in the context of VRPs, and various measures for optimizing such objectives have been proposed and implemented without a critical evaluation of their respective merits and consequences. This article addresses this gap by providing an analysis of classical and alternative equity functions for biobjective VRP models. In our survey, we review and categorize the existing literature on equitable VRPs. In the analysis, we identify a set of axiomatic properties that an ideal equity measure should satisfy, collect six common measures of equity, and point out important connections between their properties ...

Workload Equity in Vehicle Routing Problems: A Survey and Analysis

Workload equity in vehicle routing: The impact of alternative workload resources

https://onlinelibrary.wiley.com/doi/pdf/10.1002/net.21876

Piotr Matl

Papers

A concise guide to existing and emerging vehicle routing problem variants

A concise guide to existing and emerging vehicle routing problem variants.

Workload Equity in Vehicle Routing Problems: A Survey and Analysis

Workload equity in vehicle routing: The impact of alternative workload resources

Leveraging single-objective heuristics to solve bi-objective problems: Heuristic box splitting and its application to vehicle routing