2,024 research outputs found

    The MATSim Network Flow Model for Traffic Simulation Adapted to Large-Scale Emergency Egress and an Application to the Evacuation of the Indonesian City of Padang in Case of a Tsunami Warning

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    The evacuation of whole cities or even regions is an important problem, as demonstrated by recent events such as evacuation of Houston in the case of Hurricane Rita or the evacuation of coastal cities in the case of Tsunamis. This paper describes a complex evacuation simulation framework for the city of Pandang, with approximately 1,000,000 inhabitants. Padang faces a high risk of being inundated by a tsunami wave. The evacuation simulation is based on the MATSim framework for large-scale transport simulations. Different optimization parameters like evacuation distance, evacuation time, or the variation of the advance warning time are investigated. The results are given as overall evacuation times, evacuation curves, an detailed GIS analysis of the evacuation directions. All these results are discussed with regard to their usability for evacuation recommendations.BMBF, 03G0666E, Verbundprojekt FW: Last-mile Evacuation; Vorhaben: Evakuierungsanalyse und Verkehrsoptimierung, Evakuierungsplan einer Stadt - Sonderprogramm GEOTECHNOLOGIENBMBF, 03NAPAI4, Transport und Verkehr: Verbundprojekt ADVEST: Adaptive Verkehrssteuerung; Teilprojekt Verkehrsplanung und Verkehrssteuerung in Megacitie

    Key challenges in agent-based modelling for geo-spatial simulation

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    Agent-based modelling (ABM) is fast becoming the dominant paradigm in social simulation due primarily to a worldview that suggests that complex systems emerge from the bottom-up, are highly decentralised, and are composed of a multitude of heterogeneous objects called agents. These agents act with some purpose and their interaction, usually through time and space, generates emergent order, often at higher levels than those at which such agents operate. ABM however raises as many challenges as it seeks to resolve. It is the purpose of this paper to catalogue these challenges and to illustrate them using three somewhat different agent-based models applied to city systems. The seven challenges we pose involve: the purpose for which the model is built, the extent to which the model is rooted in independent theory, the extent to which the model can be replicated, the ways the model might be verified, calibrated and validated, the way model dynamics are represented in terms of agent interactions, the extent to which the model is operational, and the way the model can be communicated and shared with others. Once catalogued, we then illustrate these challenges with a pedestrian model for emergency evacuation in central London, a hypothetical model of residential segregation tuned to London data which elaborates the standard Schelling (1971) model, and an agent-based residential location built according to spatial interactions principles, calibrated to trip data for Greater London. The ambiguities posed by this new style of modelling are drawn out as conclusions

    Drawing the line: balancing the spatial requirements of customer and contractor in occupied refurbishment

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    In planning the refurbishment of railway stations the spatial needs of the contractor and ofthe ongoing business stakeholders have to be balanced. A particular concern is thedisruptive effect of construction works upon pedestrian movement.RaCMIT (Refurbishment and Customer Movement Integration Tool) is a research projectaimed at addressing this problem through combining the knowledge of the client projectmanager, the construction planner and the pedestrian modelling expert.The objective of the research is to develop a decision protocol (based on problemsencountered in two case studies) facilitating optimisation of overall project value to theclient?s business.Research observations as well as current literature suggest that:? for overall decision-making, opportunities may be lost (under current practice) forminimising joint project cost/revenue disruption and? for spatial decision-making, temporary station configuration during construction(and not just overall pedestrian capacity) is a significant variable for both businessand safety outcomes. In planning the refurbishment of railway stations the spatial needs of the contractor and ofthe ongoing business stakeholders have to be balanced. A particular concern is thedisruptive effect of construction works upon pedestrian movement.RaCMIT (Refurbishment and Customer Movement Integration Tool) is a research projectaimed at addressing this problem through combining the knowledge of the client projectmanager, the construction planner and the pedestrian modelling expert.The objective of the research is to develop a decision protocol (based on problemsencountered in two case studies) facilitating optimisation of overall project value to theclient?s business.Research observations as well as current literature suggest that:? for overall decision-making, opportunities may be lost (under current practice) forminimising joint project cost/revenue disruption and? for spatial decision-making, temporary station configuration during construction(and not just overall pedestrian capacity) is a significant variable for both businessand safety outcomes

    Modelling shared space users via rule-based social force model

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    The promotion of space sharing in order to raise the quality of community living and safety of street surroundings is increasingly accepted feature of modern urban design. In this context, the development of a shared space simulation tool is essential in helping determine whether particular shared space schemes are suitable alternatives to traditional street layouts. A simulation tool that enables urban designers to visualise pedestrians and cars trajectories, extract flow and density relation in a new shared space design and achieve solutions for optimal design features before implementation. This paper presents a three-layered microscopic mathematical model which is capable of representing the behaviour of pedestrians and vehicles in shared space layouts and it is implemented in a traffic simulation tool. The top layer calculates route maps based on static obstacles in the environment. It plans the shortest path towards agents' respective destinations by generating one or more intermediate targets. In the second layer, the Social Force Model (SFM) is modified and extended for mixed traffic to produce feasible trajectories. Since vehicle movements are not as flexible as pedestrian movements, velocity angle constraints are included for vehicles. The conflicts described in the third layer are resolved by rule-based constraints for shared space users. An optimisation algorithm is applied to determine the interaction parameters of the force-based model for shared space users using empirical data. This new three-layer microscopic model can be used to simulate shared space environments and assess, for example, new street designs

    Balancing operating revenues and occupied refurbishment costs 1: problems of defining project success factors and selecting site planning methods

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    In planning the refurbishment of railway stations the spatial needs of the contractor and of the ongoing business stakeholders have to be balanced. A particular concern is the disruptive effect of construction works upon pedestrian movement. RaCMIT (Refurbishment and Customer Movement Integration Tool) was a research project aimed at addressing this problem. The objective of the research was to develop a decision protocol facilitating optimisation of overall project value to the client's business. This paper (the first of two) presents a framework for considering public disruption in occupied refurbishment using two case studies in large railway stations as examples. It briefly describes new tools which (combined with existing techniques) assist decision making in the management of disruption. It links strategic with sitebased decision making and suggests how public disruption may be treated as a variable to be jointly optimised along with traditional criteria such as time, cost and quality. Research observations as well as current literature suggest that for overall decision-making, opportunities may be lost (under current practice) for minimising joint project cost/revenue disruption, and, for spatio-temporal site decision-making, effective and efficient tools now exist to model both sides of the construction site boundary

    Calibration and Validation of A Shared space Model: A Case Study

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    Shared space is an innovative streetscape design that seeks minimum separation between vehicle traffic and pedestrians. Urban design is moving toward space sharing as a means of increasing the community texture of street surroundings. Its unique features aim to balance priorities and allow cars and pedestrians to coexist harmoniously without the need to dictate behavior. There is, however, a need for a simulation tool to model future shared space schemes and to help judge whether they might represent suitable alternatives to traditional street layouts. This paper builds on the authors’ previously published work in which a shared space microscopic mixed traffic model based on the social force model (SFM) was presented, calibrated, and evaluated with data from the shared space link typology of New Road in Brighton, United Kingdom. Here, the goal is to explore the transferability of the authors’ model to a similar shared space typology and investigate the effect of flow and ratio of traffic modes. Data recorded from the shared space scheme of Exhibition Road, London, were collected and analyzed. The flow and speed of cars and segregation between pedestrians and cars are greater on Exhibition Road than on New Road. The rule-based SFM for shared space modeling is calibrated and validated with the real data. On the basis of the results, it can be concluded that shared space schemes are context dependent and that factors such as the infrastructural design of the environment and the flow and speed of pedestrians and vehicles affect the willingness to share space

    From individual behaviour to an evaluation of the collective evolution of crowds along footbridges

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    This paper proposes a crowd dynamic macroscopic model grounded on microscopic phenomenological observations which are upscaled by means of a formal mathematical procedure. The actual applicability of the model to real world problems is tested by considering the pedestrian traffic along footbridges, of interest for Structural and Transportation Engineering. The genuinely macroscopic quantitative description of the crowd flow directly matches the engineering need of bulk results. However, three issues beyond the sole modelling are of primary importance: the pedestrian inflow conditions, the numerical approximation of the equations for non trivial footbridge geometries, and the calibration of the free parameters of the model on the basis of in situ measurements currently available. These issues are discussed and a solution strategy is proposed.Comment: 23 pages, 10 figures in J. Engrg. Math., 201
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