10,158 research outputs found

    Intelligent Transportation Systems: Fusing Computer Vision and Sensor Networks for Traffic Management

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    Intelligent Transportation Systems (ITS) represent a pivotal approach to addressing the complex challenges posed by modern-day urban mobility. By seamlessly integrating computer vision and sensor networks, ITS offer a comprehensive solution for traffic management, safety enhancement, and environmental sustainability. This paper delves into the synergistic fusion of computer vision and sensor networks within the framework of ITS, emphasizing their collective role in optimizing traffic flow, mitigating congestion, and enhancing overall road safety. Leveraging cutting-edge technologies such as machine learning, image processing, and Internet of Things (IoT), ITS harness real-time data acquisition and analytics capabilities to facilitate informed decision-making by transportation authorities. Through a comprehensive review of recent advancements, challenges, and opportunities, this paper illuminates the transformative potential of integrating computer vision and sensor networks in ITS. Furthermore, it presents compelling case studies and exemplary applications, showcasing the tangible benefits of this fusion across diverse traffic management scenarios. Ultimately, this paper advocates for the widespread adoption of integrated ITS solutions as a means to usher in a new era of smarter, safer, and more sustainable urban transportation systems

    Transit-based emergency evacuation modeling with microscopic simulation

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    Several recent mass evacuations, including those in advance of Hurricane Katrina in New Orleans and Hurricane Rita in Houston, have demonstrated the effects of limited planning for carless populations. The lack of planning left a significant portion of the mobility-limited population of both these cities unable to flee in advance of the storms. Since 2005 however, both of these cities (as well as others across the United States) have developed transit assisted mass evacuation plans at various levels of detail. Since these plans are relatively recent and do not have a history of experience on which to base their performance, it is difficult to know how well, or even if, they will work. This research describes one of the first attempts to systematically model and simulate transit-based evacuation strategies. In it, the development of and the results gained from an application of the TRANSIMS agent-based transportation simulation system to model assisted evacuation plans of New Orleans are described. In the research, a range of varying conditions were evaluated over a two-day evacuation period, including two alternative evacuation transit routing scenarios and four alternative network loading and demand generation scenarios resulting in eight evacuation scenarios. In the research, average travel time and total evacuation time were used to compare the results of a range of conditions over a two-day evacuation period, including two alternative transit evacuation routing plans and four alternative network loading scenarios. Among the general findings of the research was that the most effective scenarios of transit-based evacuation were those that were carried out during time periods during which the auto-based evacuation was in its “lull” (non-peak/overnight) periods. These conditions resulted in up to a 24 percent reduction in overall travel time and up to 56 percent reduction in the total evacuation time when compared to peak evacuation conditions. It was also found that routing buses to alternate arterial routes reduced the overall travel time by up to 56 percent and the total evacuation time by up to 22 percent. The impact of including transit evacuation on the network traffic operation was also tested using average evacuation speed and queue length, it was found that the transit evacuation had no impact on arterial traffic operation but it increased the average queue length on the interstate evacuation route. An evaluation of the transit-based evacuation plan was also completed. It was found that at least 68 percent of the transit dependent evacuees spent half an hour or less not on transit (walking towards the bus stop and/or waiting at the bus stop) and only 0.19 percent of them spent more than an hour not on transit in their evacuation trip. Finally, the number of buses needed for the carless evacuation under each evacuation scenario was estimated. A total of 56, 42, 61, and 43 local buses, for transporting people from the pickup locations to the processing centers, were required for network loading scenarios A, B, C, and D respectively. Also, 601 RTA buses, for transporting people from the processing centers to shelters, were needed

    Modelling human network behaviour using simulation and optimization tools: the need for hybridization

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    The inclusion of stakeholder behaviour in Operations Research / Industrial Engineering (OR/IE) models has gained much attention in recent years. Behavioural and cognitive traits of people and groups have been integrated in simulation models (mainly through agent-based approaches) as well as in optimization algorithms. However, especially the influence of relations between different actors in human networks is a broad and interdisciplinary topic that has not yet been fully investigated. This paper analyses, from an OR/IE point of view, the existing literature on behaviour-related factors in human networks. This review covers different application fields, including: supply chain management, public policies in emergency situations, and Internet-based human networks. The review reveals that the methodological approach of choice (either simulation or optimization) is highly dependent on the application area. However, an integrated approach combining simulation and optimization is rarely used. Thus, the paper proposes the hybridization of simulation with optimization as one of the best strategies to incorporate human behaviour in human networks and the resulting uncertainty, randomness, and dynamism in related OR/IE models.Peer Reviewe

    From Social Simulation to Integrative System Design

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    As the recent financial crisis showed, today there is a strong need to gain "ecological perspective" of all relevant interactions in socio-economic-techno-environmental systems. For this, we suggested to set-up a network of Centers for integrative systems design, which shall be able to run all potentially relevant scenarios, identify causality chains, explore feedback and cascading effects for a number of model variants, and determine the reliability of their implications (given the validity of the underlying models). They will be able to detect possible negative side effect of policy decisions, before they occur. The Centers belonging to this network of Integrative Systems Design Centers would be focused on a particular field, but they would be part of an attempt to eventually cover all relevant areas of society and economy and integrate them within a "Living Earth Simulator". The results of all research activities of such Centers would be turned into informative input for political Decision Arenas. For example, Crisis Observatories (for financial instabilities, shortages of resources, environmental change, conflict, spreading of diseases, etc.) would be connected with such Decision Arenas for the purpose of visualization, in order to make complex interdependencies understandable to scientists, decision-makers, and the general public.Comment: 34 pages, Visioneer White Paper, see http://www.visioneer.ethz.c

    Evaluating the Suitability of Phased Evacuation and Contraflow for the Evacuation of Boston\u27s Coastal Population

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    Because the city of Boston rests along the Atlantic coast and is highly vulnerable to flooding from hurricanes, local emergency planners have considered utilizing phased evacuation and contraflow strategies as a means to more effectively evacuate. This research attempted to determine whether phased evacuation or contraflow are suitable evacuation strategies that can be incorporated into Boston\u27s evacuation plan in order to increase the evacuation rate and reduce motor vehicle congestion. A computer simulation evaluating the use and non-use of phased evacuation and contraflow was performed. The simulated evacuation included 50% of the population from South Boston and the Columbia Point peninsula of Dorchester and a 20% shadow evacuation from downtown Boston. This research concludes that when an evacuation anticipates moving 60,000 vehicles or less from coastal areas, contraflow may not be necessary, while phased evacuation will require thorough planning prior to implementation to avoid extending an evacuation beyond the scheduled time frame

    The Multi-Agent Transport Simulation MATSim

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    "The MATSim (Multi-Agent Transport Simulation) software project was started around 2006 with the goal of generating traffic and congestion patterns by following individual synthetic travelers through their daily or weekly activity programme. It has since then evolved from a collection of stand-alone C++ programs to an integrated Java-based framework which is publicly hosted, open-source available, automatically regression tested. It is currently used by about 40 groups throughout the world. This book takes stock of the current status. The first part of the book gives an introduction to the most important concepts, with the intention of enabling a potential user to set up and run basic simulations.The second part of the book describes how the basic functionality can be extended, for example by adding schedule-based public transit, electric or autonomous cars, paratransit, or within-day replanning. For each extension, the text provides pointers to the additional documentation and to the code base. It is also discussed how people with appropriate Java programming skills can write their own extensions, and plug them into the MATSim core. The project has started from the basic idea that traffic is a consequence of human behavior, and thus humans and their behavior should be the starting point of all modelling, and with the intuition that when simulations with 100 million particles are possible in computational physics, then behavior-oriented simulations with 10 million travelers should be possible in travel behavior research. The initial implementations thus combined concepts from computational physics and complex adaptive systems with concepts from travel behavior research. The third part of the book looks at theoretical concepts that are able to describe important aspects of the simulation system; for example, under certain conditions the code becomes a Monte Carlo engine sampling from a discrete choice model. Another important aspect is the interpretation of the MATSim score as utility in the microeconomic sense, opening up a connection to benefit cost analysis. Finally, the book collects use cases as they have been undertaken with MATSim. All current users of MATSim were invited to submit their work, and many followed with sometimes crisp and short and sometimes longer contributions, always with pointers to additional references. We hope that the book will become an invitation to explore, to build and to extend agent-based modeling of travel behavior from the stable and well tested core of MATSim documented here.

    DEVELOPMENT OF A MIXED-FLOW OPTIMIZATION SYSTEM FOR EMERGENCY EVACUATION IN URBAN NETWORKS

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    In most metropolitan areas, an emergency evacuation may demand a potentially large number of evacuees to use transit systems or to walk over some distance to access their passenger cars. In the process of approaching designated pick-up points for evacuation, the massive number of pedestrians often incurs tremendous burden to vehicles in the roadway network. Hence, one critical issue in a multi-modal evacuation planning is the effective coordination of the vehicle and pedestrian flows by considering their complex interactions. The purpose of this research is to develop an integrated system that is capable of generating the optimal evacuation plan and reflecting the real-world network traffic conditions caused by the conflicts of these two types of flows. The first part of this research is an integer programming model designed to optimize the control plans for massive mixed pedestrian-vehicle flows within the evacuation zone. The proposed model, integrating the pedestrian and vehicle networks, can effectively account for their potential conflicts during the evacuation. The model can generate the optimal routing strategies to guide evacuees moving toward either their pick-up locations or parking areas and can also produce a responsive plan to accommodate the massive pedestrian movements. The second part of this research is a mixed-flow simulation tool that can capture the conflicts between pedestrians, between vehicles, and between pedestrians and vehicles in an evacuation network. The core logic of this simulation model is the Mixed-Cellular Automata (MCA) concept, which, with some embedded components, offers a realistic mechanism to reflect the competing and conflicting interactions between vehicle and pedestrian flows. This study is expected to yield the following contributions * Design of an effective framework for planning a multi-modal evacuation within metropolitan areas; * Development of an integrated mixed-flow optimization model that can overcome various modeling and computing difficulties in capturing the mixed-flow dynamics in urban network evacuation; * Construction and calibration of a new mixed-flow simulation model, based on the Cellular Automaton concept, to reflect various conflicting patterns between vehicle and pedestrian flows in an evacuation network

    Great East Japan Earthquake, JR East Mitigation Successes, and Lessons for California High-Speed Rail, MTI Report 12-37

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    California and Japan both experience frequent seismic activity, which is often damaging to infrastructure. Seismologists have developed systems for detecting and analyzing earthquakes in real-time. JR East has developed systems to mitigate the damage to their facilities and personnel, including an early earthquake detection system, retrofitting of existing facilities for seismic safety, development of more seismically resistant designs for new facilities, and earthquake response training and exercises for staff members. These systems demonstrated their value in the Great East Japan Earthquake of 2011 and have been further developed based on that experience. Researchers in California are developing an earthquake early warning system for the state, and the private sector has seismic sensors in place. These technologies could contribute to the safety of the California High-Speed Rail Authority’s developing system, which could emulate the best practices demonstrated in Japan in the construction of the Los Angeles-to-San Jose segment

    Absence of freight transportation plans in state and county emergency operations plans

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    Natural disasters have the ability to disrupt structured systems in the United States, such as transportation systems and freight routes. When a natural disaster occurs, freight is forced to reroute around the effected areas. Rerouting slows recovery efforts, as well as normal transportation of goods within the United States. Therefore, natural disasters, with respect to freight routes, have widespread impacts and the possibility for acute hardship in disaster-prone areas. This thesis examines how comprehensive state and local level emergency operations plans are with respect to freight transportation rerouting following a natural disaster. Coastal cities can modify freight routes and this rerouting might affect recovery efforts and the normal flow of freight. First, seven coastal cities emergency operations plans are examined for specific elements of freight transportation planning. From there, the project determined how complete local level emergency operations plans are in terms of freight transportation and the framework needed for a freight transportation plan. The result of this research was policy recommendations to improve the resiliency of freight transportation networks surrounding coastal cities and incorporate freight transportation planning into emergency operations. The resiliency of freight routes following natural disasters is important because there can be widespread effects on the delivery of goods to the U.S. as well as recovery supplies to the effected area. If freight routes could be modeled to efficiently deliver rescue supplies and goods, while also minimizing the environmental effects, the benefits of uninterrupted service to the transportation system and society could possibly be substantial. The transportation system cannot encounter difficulties whenever a natural or manmade disaster occurs; therefore the United States needs to be better equipped to counteract interruptions in freight routes
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