13 research outputs found

    a methodology for planning a new urban car sharing system with fully automated personal vehicles

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    Purpose The paper concerns a transport system for pedestrian areas, based on a fleet of fully-automated Personal Intelligent Accessible Vehicles. The following services are provided: instant access, open ended reservation and one way trips. All these features provide users with high flexibility, but create a problem of uneven distribution of vehicles among the stations. A fully vehicle based relocation strategy is proposed: when a relocation is required vehicles automatically move among stations. The paper focuses on a methodology that allows to plan the proposed transport system for wide pedestrian areas. The methodology aims to determine the fleet dimension and the relocation strategy parameters which minimize the system cost. The system cost takes into account the level of service and the efficiency. Relocation strategy parameters define when and among which stations relocations should be performed

    Pedestrian level of service: the impact of social groups on pedestrian flow characteristics

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    A comprehensive measure of the level of pedestrian comfort can lead to an improved design of public spaces, to the appropriate dimensioning of urban infrastructure (such as airports, stations and commercial centers), and, most importantly, to a design that is more responsive to people and to that very fundamental human activity: walking. The planning and design of the pedestrian environment is based on pedestrian Levels of Service (LOS). These levels currently classify the level of comfort based on space available for movement and speed (and delay, in case of crosswalks). Guidance is provided for different area types and times of day. Although many methods of assessing pedestrian LOS have been developed, all these do not consider spontaneous pedestrian groups. However, social groups, such as friends, couples, colleagues and families, represent an important component of urban crowds. The paper presents first, an overview of the current methods for assessing pedestrian environment LOS. Then the paper presents the application of the HCM method for the evaluation of a selected site LOS. The calculation is based on collected measurements of pedestrian flow. Some critical issues and inconsistencies result. These have been reviewed and read taking into account the presence of groups in pedestrian flows

    A new urban freight distribution scheme and an optimization methodology for reducing its overall cost

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    The paper refers to an innovative urban freight distribution scheme, aimed at reducing the externalities connected with the freight delivery process. Both packages destined to commercial activities and to end consumers (e-commerce) are taken into account. Each package is characterized by an address and dimensions. In the proposed transport system, freight is firstly delivered to the UDC on the border of urban areas through trucks or trains which perform the long distance transport. After, freight is reorganized and consolidated into load units, i.e. the FURBOT boxes, according to packages dimensions and to the addresses of receivers. Each box is addressed to a temporary unloading bay and it is delivered there by a FURBOT vehicle. The receivers are in charge of collecting their packages in the related unloading bays where they have been delivered. The paper concerns a methodology for optimizing this freight transport system's performances. The overall methodology receives in input the actual freight demand and the road network, and finds the transport system parameters (number of required FURBOT boxes, their temporary unloading bay, the FURBOT fleet dimension and the FURBOT vehicle routing) that minimize the system overall cost. The overall cost is a sum of the users' cost, which depends on the distance they have to walk for collecting their packages in the FURBOT box, and of the operator's cost, which depends on the number of required boxes, the total distance travelled by the FURBOT vehicles and the required number of FURBOT vehicles. The overall procedure has been applied to the case study of Barreiro old town, a suburb of Lisbon, Portugal

    The packages clustering optimisation in the logistics of the last mile freight distribution

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    The paper refers to the modelling and simulation of an innovative urban freight distribution scheme. Packages destined for receivers in an urban area are firstly delivered to the urban distribution centre (UDC); each package is characterised by an address and dimensions. The load units are consolidated in the UDC with packages. Each load unit is addressed to a temporary unloading bay, where receivers are after in charge of collecting their packages. The paper concerns a methodology for the load units consolidation which minimises the overall distance travelled by receivers, taking into account the load unit capacity and the maximum walking distance the receivers accept to collect their packages. A fuzzy k-means clustering algorithm has been adopted. The fuzzy clustering algorithm is recalled by a simulation model of the proposed transport system. The methodology has been applied to the case study of the historic city centre of Genoa, Italy

    Optimization of the FURBOT urban freight transport scheme

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    The paper refers to an innovative urban freight distribution scheme, aimed at reducing the externalities connected with the freight delivery process. Both packages destined to commercial activities and to end consumers (e-commerce) are taken into account. Each package is characterized by an address and dimensions. In the proposed transport system, freight is firstly delivered to the urban distribution centre on the border of urban areas through trucks or trains which perform the long distance transport. After, freight is reorganized and consolidated into special load units (FURBOT boxes), according to packages dimensions and to the addresses of receivers. Each box is addressed to a temporary unloading bay and it is delivered there by a smalllelectrically powered vehicle (FURBOT vehicle). The paper concerns a methodology for optimizing this freight transport system's performances. The input data are the actual freight demand, the road network and the public policies. The methodology determines the best number of FURBOT boxes which minimizes the system cost. The overall cost is a sum of the users cost, which depends on the distance they have to walk for collecting their packages in the FURBOT box, and of the operator cost, which depends on the number of boxes, and the total distance travelled by the FURBOT vehicles. The minimization problem has been approached by a Simulated Annealing procedure. The methodology recalls two sub-problems: a first sub-problem to determine the optimum clustering of packages in the FURBOT boxes, and a second sub problem to determine the best routing of FURBOT vehicles. The methodology has been applied to the case study of Genoa city centre, Italy

    Pedestrian level of service: the impact of social groups on pedestrian flow characteristics

    No full text
    A comprehensive measure of the level of pedestrian comfort can lead to an improved design of public spaces, to the appropriate dimensioning of urban infrastructure (such as airports, stations and commercial centers), and, most importantly, to a design that is more responsive to people and to that very fundamental human activity: walking. The planning and design of the pedestrian environment is based on pedestrian Levels of Service (LOS). These levels currently classify the level of comfort based on space available for movement and speed (and delay, in case of crosswalks). Guidance is provided for different area types and times of day. Although many methods of assessing pedestrian LOS have been developed, all these do not consider spontaneous pedestrian groups. However, social groups, such as friends, couples, colleagues and families, represent an important component of urban crowds. The paper presents first, an overview of the current methods for assessing pedestrian environment LOS. Then the paper presents the application of the HCM method for the evaluation of a selected site LOS. The calculation is based on collected measurements of pedestrian flow. Some critical issues and inconsistencies result. These have been reviewed and read taking into account the presence of groups in pedestrian flows

    Level of service of pedestrian facilities: Modelling human comfort perception in the evaluation of pedestrian behaviour patterns

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    The paper presents a new methodology for evaluating the quality of operation of pedes- trian facilities: the methodology is based on the individual level of comfort perceived by each pedestrian that moves in the area. At each time instant, each pedestrian perceives a comfort level which is a function of the space they feel currently available and of his required space. The required space depends on the subject\u2019s walking direction as well as on physical and psychological factors. The available space depends on the current positions of pedestrians. The proposed methodol- ogy quantifies the current discomfort due to pedestrian interactions as a continuous function of the interpersonal distances. The proposed methodology has been applied to empirical data. The experimental data are presented, discussed and compared with widely accepted level of service assessment methods

    Innovative strategies for urban car-sharing systems and a simulator to assess their performance

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    In this paper, three innovative car-sharing systems for urban areas are proposed, based on fleets of individual intelligent vehicles with three service characteristics: instant access, open-ended reservations and one-way trips. These features provide high flexibility but create an uneven distribution of vehicles among stations. Therefore, relocation of vehicles must be performed. Three different system procedures are proposed: in the first system, relocations are performed by users; in the other two, vehicles relocate automatically, thanks to their automation. In the first two systems, vehicles are accessible only at stations, whereas in the third they are also accessible along roads. In order to provide transport managers with a tool to test systems in different realities, an object-oriented simulator is developed. The simulation provides outputs of system performance, in terms of user waiting times and system efficiency. The proposed systems are simulated for the city of Genoa, in Italy, and a comparative analysis is presented. \ua9 2015, \ua9 2015 Taylor & Francis
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