50 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

    Risk Minimizing Evacuation Strategies under Uncertainty

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    This paper presents results on the simulation of the evacuation of the city of Padang with approximately 1,000,000 inhabitants. The model used is MATSim (www.matsim.org). Three different strategies were applied: shortest path solution, user optimum, system optimum, together with a constraint that moves should reduce risk whenever possible. The introduction of the risk minimization increases the overall required safe egress time (RSET). The differences between the RSET for the three risk minimizing strategies are small. Further quantities used for the assessment of the evacuation are the formation of congestion and the individual RSETs (in comparison with the available SET).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

    Seepage of Smaller Vehicles under Heterogeneous Traffic Conditions

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    In the direction of complex heterogeneous traffic modeling, the present study proposes a model to simulate the behavior of smaller vehicles in the congested regime called seepage action. As the name suggests, in congested part of links, smaller vehicles like motorbikes and bikes do not stop at the end of queue. Instead, they move continuously across the gaps between the stationary congested vehicles and come in front. This behavior is rarely modeled and quantified even though it is common praxis in most of the developing nations. In order to facilitate this behavior, a state of the art queue model is modified to allow for seepage in congested regime. Furthermore, the concept of backward traveling holes is introduced. Thus, the congested branch of the fundamental diagram is modeled more realistic

    Large Scale Microscopic Evacuation Simulation

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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. A robust and flexible simulation framework for such large-scale disasters helps to predict the evacuation process. Existing methods are either geared towards smaller problems (e.g. Cellular Automata techniques or methods based on differential equations) or are not microscopic (e.g. methods based on dynamic traffic assignment). This paper presents a technique that is both microscopic and capable to process large problems.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

    Incorporating within link dynamics in an agent-based computationally faster and scalable queue model

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    The growing pace of urbanization increases the need of simulation models to handle large-scale scenarios in reasonable time. The present study proposes a fast spatial queue model, which is anchored to an agent-based travel demand simulation framework. The existing queue model is extended to produce more realistic flow dynamics by introducing backward travelling holes to mixed traffic conditions. In this approach, the space freed by a leading vehicle is not immediately available to the following vehicle. The resulting dynamics resembles Newell's simplified kinematic wave model. The space freed corresponding to each leaving vehicle is named as hole' and, as following vehicles occupy the space freed by leading vehicles, the hole travels backward. This results in triangular fundamental diagrams for traffic flow. The robustness of the model is tested with flow density and average bike passing rate contours. Spatio-temporal trajectories are presented to differentiate the queuing patterns. Finally, a comparison of the computational performance of the different link and traffic dynamics of the queue model is made

    A Review of Pedestrian Flow Characteristics and Level of Service over Different Pedestrian Facilities

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    Present paper reviewed the past studies on pedestrian flow characteristics (such as speed, flow, density, space, free-flow speed and jam density) and development of Pedestrian Level of Service (PLOS) for various pedestrian facilities (i.e., sidewalk, walkway, crosswalk, grade separated, stairways and escalators). Fundamental relationships (between speed and density) were observed over different facilities and were found to be significantly different. The fundamental relationships for sidewalk facility predicted the range of free flow speeds to be 65 − 85 m/min and jam densities to be 3.5 − 5.3 ped/m2. The minimum and maximum pedestrian speeds over sidewalk facility in different countries observed were 52 m/min and 98 m/min respectively, with a mean speed of 79 m/min. The male pedestrians walked at 4 − 9 m/min higher speed in comparison to their female counterparts; while the older pedestrians walked at 15 − 20 m/min lower speed than the younger ones over the various types of crosswalk facilities. Similarly, speed-density relationships for ascending and descending stairways showed that the difference between the two directions varied between 4 − 12 m/min, and that the speed was significantly higher in case of descending direction. Moreover, the jam densities for stairways were also observed to be lower in case of descending direction, as the pedestrians generally maintain higher gap (than in ascending direction) with other pedestrians in front to avoid pushing and the risk of falling down. The flow characteristics were significantly influenced by the type of facility, width, age, gender and location of the study. Primarily factors such as physique (height), culture (dress), attractions (presence of hawkers located along sidewalks), friction (due to parked vehicles), purpose of walking trip and environmentl conditions were the main reasons for pedestrians of countries such as Saudi Arabia, Iraq, Bangladesh, Indonesia and Sri-Lanka to walk significantly slower than the counterparts pedestrians in the USA, UK or Canada.The review conducted on the PLOS mainly looked into the type of survey conducted (qualitative vs. quantitative), LOS parameters and the various software/models used in development of LOS. Researchers from the USA and Japan preferably used both qualitative and quantitative approaches in defining LOS over sidewalks; while in India, China and Malaysia qualitative method was highly preferred. Pedestrian volume, safety, surface, obstruction and width were observed as essential parameters for qualitative survey while density, flow rate, pedestrian speed and width were used in quantitative survey for sidewalks. In developing the PLOS over sidewalk facility; Conjoint analysis, Landis method, HCM method, affinity propagation cluster algorithm and Gainesville method were preferred by various researchers. Studies conducted over crosswalk facility measured space, flow rate, vehicle volume and delay as the most significant factors in developing LOS based on quantitative technique; while vehicle speed, pedestrian volume and traffic control were mostly used for LOS development using qualitative technique.

    Evacuation simulation with limited capacity sinks

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    We heuristically solve an evacuation problem with limited capacity shelters. An evolutionary learning algorithm is developed for the combined route- and shelter-assignment problem. It is complemented with a heuristic method for the fair minimization of shelter capacities. Different behavioral assumptions fair vs. globally optimal) are investigated. The proposed approaches are discussed in the context of a real-world tsunami evacuation problem

    Optimal Evacuation Solutions for Large-Scale Scenarios

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    Evacuation, the process of moving people out of potentially dangerous areas, is a key response to many threats. Planning such an evacuation is therefore important, especially in large-scale emergencies, where routing becomes non-trivial. This paper deals with the optimization and simulation of the evacuation process. We draw our data from the study of the city of Padang in Indonesia, with its high threat of tsunami waves.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 MegacitiesDFG, FZT 86, Matheon - Mathematik fĂŒr SchlĂŒsseltechnologien: Modellierung, Simulation und Optimierung realer Prozess

    The representation and implementation of time-dependent inundation in large-scale microscopic evacuation simulations

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    Multi-agent simulation has increasingly been used for transportation simulation in recent years. With current techniques, it is possible to simulate systems consisting of several million agents. Such multi-agent simulations have been applied to whole cities and even large regions. In this paper it is demonstrated how to adapt an existing multi-agent transportation simulation framework to large-scale pedestrian evacuation simulation. The underlying flow model simulates the traffic-based on a simple queue model where only free speed, bottleneck capacities, and space constraints are taken into account. The queue simulation, albeit simple, captures the most important aspects of evacuations such as the congestion effects of bottlenecks and the time needed to evacuate the endangered area. In the case of an evacuation simulation the network has time-dependent attributes. For instance, large-scale inundations or conflagrations do not cover all the endangered area at once. These time-dependent attributes are modeled as network change events. Network change events are modifying link parameters at predefined points in time. The simulation framework is demonstrated through a case study for the Indonesian city of Padang, which faces a high risk of being inundated by a tsunami.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
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