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

Optimization of Electric Bus Scheduling for Mixed Passenger and Freight Flow in an Urban-Rural Transit System

Transport accessibility and urban-rural connectivity are seen as critical aspects of rural economic development. In the transit network, passenger flow between urban-rural corridors demonstrates directional imbalances and low utilization of scarce resources. Freight transportation, on the other hand, lags due to poor geography, high operating costs, and scattered demand. This paper proposes a new mode of public transit that integrates passenger and freight transport, providing a carrier for logistics while compensating for the low utilization of passenger transport. In this mode, each timetabled round trip is divided into one dedicated passenger trip with high demand and one mixed-flow trip with on-demand requests. A space-time-state network is constructed considering the picking-up time window, loading/unloading service time, and electric bus energy replenishment. A mixed-integer linear programming model is developed to optimize the bus schedule that covers the travel demands and the charging requests with minimized travel costs. A Lagrangian relaxation framework with a dynamic programming algorithm and sub-gradient method is presented for problem-solving. The real-life rural-urban transport instance and a simulated network demonstrate the operation of the new mode and validate the efficiency of the proposed method. The innovative concept and the optimization framework are expected to serve as a reference for public administration to alleviate passenger and freight transportation bottlenecks in the urban-rural context

Smart Urban Planning : Evaluating Urban Logistics Performance of Innovative Solutions and Sustainable Policies in the Venice Lagoon : the Results of a Case Study

Currently, remarkable gaps of operational, social and environmental efficiency and overall sub-optimization of the logistics and mobility systems exist in urban areas. There is then the need to promote and assess innovative transport solutions and policy-making within SUMPs (Sustainable Urban Mobility Plans) to deal with such critical issues in order to improve urban sustainability. The paper focuses on the case study of the Venice Lagoon, where islands—despite representing a relevant feature of urban planning—face a tremendous lack of accessibility, depopulation, social cohesion and they turn out to be poorly connected. By developing an original scenario-building methodological framework and performing data collection activities, the purpose of the paper consists of assessing the feasibility of a mixed passenger and freight transport system —sometimes called cargo hitching. Mixed passenger and freight systems/cargo hitching are considered as an innovative framework based on the integration of freight and passenger urban systems and resources to optimize the existing transport capacity, and thus, urban sustainability. Results show that the overall existing urban transport capacity can accommodate urban freight flows on main connections in the Lagoon. The reduction in spare public transport capacity, as well as in the number (and type) of circulating freight boats show—in various scenarios—the degree of optimization of the resulting urban network configuration and the positive impacts on urban sustainability. This paves the way for the regulatory framework to adopt proposed solutions

Towards the adoption of technological innovations: decision processes in transport policy definition

The widespread of technological innovations is rapidly changing the way modern societies are organized. Such phenomenon highly affects the economy of most developed countries (and, more recently, of developing countries, too), influencing work organization and habits. Besides, technological innovations modify the way in which transport systems are organized, by introducing new transport solutions as well as by upgrading the performances of the existing transport systems, in accordance to a more efficient organization. Several tools have been designed to predict the effects of the adoption of technological innovations in transport. The aim of this paper is to deal with the decision processes involved in the definition of the transport policies for the introduction of such technological solutions. To do this the way in which the new transport solutions affect the local context is analysed. In particular, this work aim to identify the most relevant attributes which influence the decision processes on the adoption of such technological solutions, with reference to their impact on the territory and on the economic activities. To do this, the analysis focuses on the effects involved by the use of wireless technologies and radio frequency identification into seaport infrastructures. Such technologies enable an easier identification of goods in transport terminals; this implies advantages in the organization of the terminal activities, allowing lower time and costs for handling, and at the same time it ensures a greater compliance to security requirements, thus upgrading the level of the performances in these transport systems. On the other hand, the effects of the improvements in transport systems affect the economic context in which transport infrastructures are set. Thus, the adoption of such a technological innovation can represent the chance for local development of the region, due to the better performances of the transport system and to the consequent increased territorial accessibility.

Collaborative urban transportation : Recent advances in theory and practice

We thank the Leibniz Association for sponsoring the Dagstuhl Seminar 16091, at which the work presented here was initiated. We also thank Leena Suhl for her comments on an early version of this work. Finally, we thank the anonymous reviewers for the constructive comments.Peer reviewedPostprin

Integrated urban freight logistics combining passenger and freight flows - Mathematical model proposal

The aim of this research is to propose an urban logistics distribution service which benefits from the already installed passenger transport network. This service is based upon the concept of integration of the existing passenger transport network with the urban freight process. The aim is to reduce the number of fossil combustion powered commercial vehicles traveling within city boundaries, solely for goods transportation, thus contributing to reduce negative effects of urban logistics activities, namely pollution, noise, traffic congestion and accidents. Also, integrating goods and passenger flows will promote higher efficiency rates for the passenger transport network and enhance living conditions within major urban centers. A mathematical model for the operational planning of the proposed urban logistics distribution service is proposed. This model consists of assigning origins loads (or requests) to inbound hubs (bus operator centers), transferring the inbound hubs loads to a bus service, and transferring the bus loads to bus stops, to be collected by micro-logistics operators operating environmentally friendly vehicle fleets. The objective is to minimize the total service time while assuring services synchronization along the network and balancing the loads with the system capacities.(undefined

Integration planning of freight deliveries into passenger bus networks: exact and heuristic algorithms

With the increasing population living in cities, a growing number of small daily urban freight deliveries are performed, typically by private companies. Recently, more environmentally friendly urban logistics services have emerged to mitigate the negative effects of such activities. One example is the integration of freight deliveries into bus networks, traditionally dedicated to passenger transportation, to perform urban logistics activities within cities. In this paper, the integration of the freight delivery process into the urban bus passenger network is addressed where freight parcels are dropped by clients at bus hubs located outside the city center, transported by bus services from the hub to bus stops located in the city center, and delivered to the destination address by a last mile operator. Since bus vehicles supporting both passenger and freight flows need to be physically adapted, the aim is to support the decision-maker to select the minimum number of bus services that must be adapted for freight transportation. The optimization problem considers the freight demand uncertainty in terms of number of freight parcels, destination address, delivery time windows and last mile operator constraints which are modelled by a set of demand scenarios. An exact method based on an integer linear programming (ILP) and two heuristic algorithms based on a greedy randomized adaptive search procedure (GRASP) are proposed. The results show that the proposed optimization methods are efficient, giving valuable insights to stakeholders, in the fields of policy and practice, for the strategic decision of selecting the minimum number of buses to be physically adapted for freight transportation. In particular, the results show that all proposed optimization methods are of interest in practice since the type of problem instances for which each method is more efficient is clearly identified in the obtained computational results. Moreover, in the early stages of the integrated passenger and freight flows service, the impact on the required number of adapted bus services is mainly given by the last mile operator capacity of delivering freight from bus hubs to final parcel destinations, while the other factors (delivery time windows and distributions parcel destination addresses) do not have a significant impact on the required number of bus services.publishe

On green routing and scheduling problem

The vehicle routing and scheduling problem has been studied with much interest within the last four decades. In this paper, some of the existing literature dealing with routing and scheduling problems with environmental issues is reviewed, and a description is provided of the problems that have been investigated and how they are treated using combinatorial optimization tools