Optimization of a city logistics transportation system with mixed passengers and goods

International audienceIn this paper, we propose a mathematical model and an adaptive large neighborhood search to solve a two{tiered transportation problem arising in the distribution of goods in congested city cores. In the rst tier, goods are transported in city buses from a consolidation and distribution center to a set of bus stops. The main idea is to use the buses spare capacity to drive the goods in the city core. In the second tier, nal customers are distributed by a eet of near{zero emissions city freighters. This system requires transferring the goods from buses to city freighters at the bus stops. We model the corresponding optimization problem as a variant of the pickup and delivery problem with transfers and solve it with an adaptive large neighborhood search. To evaluate its results, lower bounds are calculated with a column generation approach. The algorithm is assessed on data sets derived from a eld study in the medium-sized city of La Rochelle in France

An adaptive large neighborhood search for a full truckload routing problem in public works

International audienceThis paper presents a truck routing and scheduling problem faced by a public works company. Itconsists of optimizing the collection and delivery of materials between sites, using a heterogeneousfleet of vehicles. These flows of materials arise in levelling works and construction of roads networks.As the quantity of demands usually exceeds the capacity of a truck, several trucks are needed tofulfill them. As a result, demands are split into full truckloads. A set of trucks routes are needed toserve a set of demands sharing a set of resources, available at pickup or delivery sites, which can beloaders or asphalt finishers in our application cases. Thus, these routes need to be synchronized ateach resource. We propose an Adaptive Large Neighborhood Search (ALNS) to solve this problem.This approach is evaluated on real instances from a public work company in France

An adaptive large neighborhood search for a vehicle routing problem with cross-dock under dock resource constraints

International audienceIn this work, we study the impact of dock resource constraints on the cost of VRPCD solutions

Shared Mobility Optimization in Large Scale Transportation Networks: Methodology and Applications

abstract: Optimization of on-demand transportation systems and ride-sharing services involves solving a class of complex vehicle routing problems with pickup and delivery with time windows (VRPPDTW). Previous research has made a number of important contributions to the challenging pickup and delivery problem along different formulation or solution approaches. However, there are a number of modeling and algorithmic challenges for a large-scale deployment of a vehicle routing and scheduling algorithm, especially for regional networks with various road capacity and traffic delay constraints on freeway bottlenecks and signal timing on urban streets. The main thrust of this research is constructing hyper-networks to implicitly impose complicated constraints of a vehicle routing problem (VRP) into the model within the network construction. This research introduces a new methodology based on hyper-networks to solve the very important vehicle routing problem for the case of generic ride-sharing problem. Then, the idea of hyper-networks is applied for (1) solving the pickup and delivery problem with synchronized transfers, (2) computing resource hyper-prisms for sustainable transportation planning in the field of time-geography, and (3) providing an integrated framework that fully captures the interactions between supply and demand dimensions of travel to model the implications of advanced technologies and mobility services on traveler behavior.Dissertation/ThesisDoctoral Dissertation Civil, Environmental and Sustainable Engineering 201

Efficient handling of synchronization in three vehicle routing problems

International audienceThis paper presents a synthesis of contributions to the solving of three vehicle routing problemsinvolving synchronization constraints. These problems are: the Pickup and Delivery Problem withTransfers (PDPT), studied during the PhD of Renaud Masson, co-advised with Olivier Péton [4], theTwo-Echelon Multiple-Trip Vehicle Routing Problem with Satellite Synchronization (2E-MTVRPSS),studied by Philippe Grangier during his PhD, co-advised with Michel Gendreau and Louis-Martin Rousseau [2], and the Heterogeneous Full Truckload Pickup and Delivery Problem with TimeWindows and Resource Synchronization(HFTPDPTW-RS), under study by Axel Grimault in hisPhD and co-advised with Nathalie Bostel [3]. All these problems have been solved with an AdaptiveLarge Neighborhood Search (ALNS).A special focus is given to the temporal feasibility evaluation of an insertion which has beenproposed for the PDPT [5] and extended to the other problems. The concept of forward time slack[6] is extended to provide a constant time feasibility test of temporal constraints. Experimentsconfirm the solving time reduction provided by the implementation of this test in a meta-heuristic

Integrating passenger and freight transportation : model formulation and insights

Integrating passenger and freight flows creates attractive business opportunities because the same transportation needs can be met with fewer vehicles and emissions. This paper seeks an integrated solution for the transportation of passenger and freight simultaneously, so that fewer vehicles are required. The newly introduced problem concerns scheduling a set of vehicles to serve the requests such that a part of the journey can be carried out on a scheduled passenger transportation service. We propose an arc-based mixed integer programming formulation for the integrated transportation system. Computational results on a set of instances provide a clear understanding on the benefits of integrating passenger and freight transportation in the current networks, considering multi-modality of traditional passenger-oriented transportation modes, such as taxi, bus, train or tram

A shared " passengers & goods " city logistics system

International audienceMany strategic planning models have been developed to help decision making in city logistics. Such models do not take into account, or very few, the flow of passengers because the considered unit does not have the same nature (a person is active and a good is passive). However, it seems fundamental to gather the goods and the passengers in one model when their respective transports interact with each other. In this context, we suggest assessing a shared passengers & goods city logistics system where the spare capacity of public transport is used to distribute goods toward the city core. We model the problem as a vehicle routing problem with transfers and give a mathematical formulation. Then we propose an Adaptive Large Neighborhood Search (ALNS) to solve it. This approach is evaluated on data sets generated following a field study in the city of La Rochelle in France