WorldWideScience

Sample records for adaptive traffic flow

  1. Traffic flow on realistic road networks with adaptive traffic lights

    de Gier, Jan; Rojas, Omar

    2010-01-01

    We present a model of traffic flow on generic urban road networks based on cellular automata. We apply this model to an existing road network in the Australian city of Melbourne, using empirical data as input. For comparison, we also apply this model to a square-grid network using hypothetical input data. On both networks we compare the effects of non-adative vs adaptive traffic lights, in which instantaneous traffic state information feeds back into the traffic signal schedule. We observe that not only do adaptive traffic lights result in better averages of network observables, they also lead to significantly smaller fluctuations in these observables. We furthermore compare two different systems of adaptive traffic signals, one which is informed by the traffic state on both upstream and downstream links, and one which is informed by upstream links only. We find that, in general, the total travel time is smallest when using the joint upstream-downstream control strategy.

  2. TRAFFIC FLOW MODEL BASED ON CELLULAR AUTOMATION WITH ADAPTIVE DECELERATION

    Shinkarev, A. A.

    2016-01-01

    This paper describes continuation of the authors’ work in the field of traffic flow mathematical models based on the cellular automata theory. The refactored representation of the multifactorial traffic flow model based on the cellular automata theory is used for a representation of an adaptive deceleration step implementation. The adaptive deceleration step in the case of a leader deceleration allows slowing down smoothly but not instantly. Concepts of the number of time steps without confli...

  3. Adaptive algorithms for identifying large flows in IP traffic

    Chabchoub, Yousra; Guillemin, Fabrice; Robert, Philippe

    2009-01-01

    We develop in this paper an adaptive algorithm based on Bloom filters in order to identify large flows. While most algorithms proposed so far in the technical literature rely on a periodic erasure of the Bloom filter, we propose in this paper to progressively decrement the various counters of the filter according to some overload criteria. When tested against real traffic traces, the proposed algorithm performs well in the sense that a high percentage of large flows in traffic are detected by the algorithm. In order to improve the accuracy of the algorithm, we introduce a shadow Bloom filter, which is less frequently decremented so that elephants have more chance of being identified. Since elephant detection issue is very close to flood attack detection, we adapt the proposed algorithm in order to detect SYN and volume flood attack in Internet traffic. The attack detection algorithm is tested against traffic traces from France Telecom collect and transit networks. Some performance issues are finally discussed...

  4. Traffic-adaptive, flow-specific medium access for wireless networks

    Walker, T. Owens; Tummala, Murali; McEachen, John

    2009-01-01

    In this report, we formally introduce the novel concept of traffic-adaptive, flow-specific medium access control and show that it outperforms contention, non-contention and hybrid medium access schemes. A traffic-adaptive, flow-specific mechanism is proposed that utilizes flow-specific queue size statistics to select between medium access modes. A general model for traffic adaptive, flow-specific medium access control is developed and it is shown that hybrid medium access as well as traditio...

  5. Optimizing Traffic Flow

    Huberman, Bernardo A.; Helbing, Dirk

    1998-01-01

    We present an economics-based method for deciding the optimal rates at which vehicles are allowed to enter a highway. The method exploits the naturally occuring fluctuations of traffic flow and is flexible enough to adapt in real time to the transient flow characteristics of road traffic. Simulations based on realistic parameter values show that this strategy is feasible for naturally occuring traffic, and that even far from optimality, injection policies can improve traffic flow. Our results...

  6. Traffic flow impacts of adaptive cruise control deactivation and (Re)activation with cooperative driver behavior

    Klunder, G.; Li, M.; Minderhoud, M.

    2009-01-01

    In 2006 in the Netherlands, a field operational test was carried out to study the effect of adaptive cruise control (ACC) and lane departure warning on driver behavior and traffic flow in real traffic. To estimate the effect for larger penetration rates, simulations were needed. For a reliable impac

  7. The Impact of Cooperative Adaptive Cruise Control on Traffic-Flow Characteristics

    Arem, van, Bart; Driel, van, J.; Visser, Ruben

    2006-01-01

    Cooperative adaptive cruise control (CACC) is an extension of ACC. In addition to measuring the distance to a predecessor, a vehicle can also exchange information with a predecessor by wireless communication. This enables a vehicle to follow its predecessor at a closer distance under tighter control. This paper focuses on the impact of CACC on traffic-flow characteristics. It uses the traffic-flow simulation model MIXIC that was specially designed to study the impact of intelligent vehicles o...

  8. Nature inspired artificial intelligence based adaptive traffic flow distribution in computer network

    Singh, Manoj Kumar

    2010-01-01

    Because of the stochastic nature of traffic requirement matrix, it is very difficult to get the optimal traffic distribution to minimize the delay even with adaptive routing protocol in a fixed connection network where capacity already defined for each link. Hence there is a requirement to define such a method, which could generate the optimal solution very quickly and efficiently. This paper presenting a new concept to provide the adaptive optimal traffic distribution for dynamic condition of traffic matrix using nature based intelligence methods. With the defined load and fixed capacity of links, average delay for packet has minimized with various variations of evolutionary programming and particle swarm optimization. Comparative study has given over their performance in terms of converging speed. Universal approximation capability, the key feature of feed forward neural network has applied to predict the flow distribution on each link to minimize the average delay for a total load available at present on t...

  9. A Flow-Level Performance Model for Mobile Networks Carrying Adaptive Streaming Traffic

    Bonald, Thomas; Elayoubi, Salah-Eddine; Lin, Yu-Ting

    2015-01-01

    International audience This paper proposes a performance model for mobile networks carrying adaptive streaming traffic. The proposed model takes into account the flow dynamics in addition to the main parameters influencing the performance of adaptive streaming, such as the playout buffer and the video bit rates. We show how to compute several performance metrics like the average video bit rate, the deficit rate, defined as the probability of having an instantaneous throughput lower than th...

  10. TRANSIMS traffic flow characteristics

    Nagel, Kai; Stretz, Paula; Pieck, Martin; Donnelly, Rick; Barrett, Christopher L.

    1997-01-01

    Knowledge of fundamental traffic flow characteristics of traffic simulation models is an essential requirement when using these models for the planning, design, and operation of transportation systems. In this paper we discuss the following: a description of how features relevant to traffic flow are currently under implementation in the TRANSIMS microsimulation, a proposition for standardized traffic flow tests for traffic simulation models, and the results of these tests for two different ve...

  11. Traffic-Adaptive Routing

    Kammenhuber, Nils

    2011-01-01

    Despite the bursty and highly volatile traffic, routing in the Internet today is optimised only on coarse time scales, as load-adaptive routing is known to induce performance deterioration by causing massive oscillations. We describe ReplEx, an universally applicable distributed algorithm for dynamic routing/traffic engineering, which is based on game theory. We show through extensive realistic simulations that ReplEx does not oscillate, and that it achieves performance gains comparable to tr...

  12. Effect of adaptive cruise control systems on mixed traffic flow near an on-ramp

    Davis, L. C.

    2007-06-01

    Mixed traffic flow consisting of vehicles equipped with adaptive cruise control (ACC) and manually driven vehicles is analyzed using car-following simulations. Simulations of merging from an on-ramp onto a freeway reported in the literature have not thus far demonstrated a substantial positive impact of ACC. In this paper cooperative merging for ACC vehicles is proposed to improve throughput and increase distance traveled in a fixed time. In such a system an ACC vehicle senses not only the preceding vehicle in the same lane but also the vehicle immediately in front in the other lane. Prior to reaching the merge region, the ACC vehicle adjusts its velocity to ensure that a safe gap for merging is obtained. If on-ramp demand is moderate, cooperative merging produces significant improvement in throughput (20%) and increases up to 3.6 km in distance traveled in 600 s for 50% ACC mixed flow relative to the flow of all-manual vehicles. For large demand, it is shown that autonomous merging with cooperation in the flow of all ACC vehicles leads to throughput limited only by the downstream capacity, which is determined by speed limit and headway time.

  13. Traffic Flow Estimates.

    Hart, Vincent G.

    1981-01-01

    Two examples are given of ways traffic engineers estimate traffic flow. The first, Floating Car Method, involves some basic ideas and the notion of relative velocity. The second, Maximum Traffic Flow, is viewed to involve simple applications of calculus. The material provides insight into specialized applications of mathematics. (MP)

  14. Traffic Flow Theory

    Maerivoet, Sven; De Moor, Bart

    2005-01-01

    The scientific field of traffic engineering encompasses a rich set of mathematical techniques, as well as researchers with entirely different backgrounds. This paper provides an overview of what is currently the state-of-the-art with respect to traffic flow theory. Starting with a brief history, we introduce the microscopic and macroscopic characteristics of vehicular traffic flows. Moving on, we review some performance indicators that allow us to assess the quality of traffic operations. A f...

  15. Traffic-flow simulation

    OMAHEN, ANDRAŽ

    2015-01-01

    This diploma thesis presents the behavior of program, which uses the traffic light enhanced transport network to simulate the traffic flow of vehicles that behave according to the IDM model. We upgraded the program to allow, for the given network, to optimize the traffic flow. Because of the overwhelming problem of road closures or their rearrangement, we added a graphical user interface with which a user can create or modify the road network to observe changes in traffic. The objective of...

  16. Improving traffic flow at a 2-to-1 lane reduction with wirelessly connected, adaptive cruise control vehicles

    Davis, L C

    2015-01-01

    Wirelessly connected vehicles that exchange information about traffic conditions can reduce delays caused by congestion. At a 2-to-1 lane reduction, the improvement in flow past a bottleneck due to traffic with a random mixture of 40% connected vehicles is found to be 52%. Control is based on connected-vehicle-reported velocities near the bottleneck. In response to indications of congestion the connected vehicles, which are also adaptive cruise control vehicles, reduce their speed in slowdown regions. Early lane changes of manually driven vehicles from the terminated lane to the continuous lane are induced by the slowing connected vehicles. Self-organized congestion at the bottleneck is thus delayed or eliminated, depending upon the incoming flow magnitude. For the large majority of vehicles, travel times past the bottleneck are substantially reduced. Control is responsible for delaying the onset of congestion as the incoming flow increases. Adaptive cruise control increases the flow out of the congested stat...

  17. Traffic Flow Management System

    Department of Transportation — TFMS is a set NAS operational tools that predict demand, identify constraints, and facilitates collaboration among NAS users to support efficient traffic flow while...

  18. A Marine Traffic Flow Model

    Tsz Leung Yip

    2013-01-01

    A model is developed for studying marine traffic flow through classical traffic flow theories, which can provide us with a better understanding of the phenomenon of traffic flow of ships. On one hand, marine traffic has its special features and is fundamentally different from highway, air and pedestrian traffic. The existing traffic models cannot be simply extended to marine traffic without addressing marine traffic features. On the other hand, existing literature on marine traffic focuses on...

  19. Online traffic flow model applying dynamic flow-density relation

    Kim, Y

    2002-01-01

    This dissertation describes a new approach of the online traffic flow modelling based on the hydrodynamic traffic flow model and an online process to adapt the flow-density relation dynamically. The new modelling approach was tested based on the real traffic situations in various homogeneous motorway sections and a motorway section with ramps and gave encouraging simulation results. This work is composed of two parts: first the analysis of traffic flow characteristics and second the development of a new online traffic flow model applying these characteristics. For homogeneous motorway sections traffic flow is classified into six different traffic states with different characteristics. Delimitation criteria were developed to separate these states. The hysteresis phenomena were analysed during the transitions between these traffic states. The traffic states and the transitions are represented on a states diagram with the flow axis and the density axis. For motorway sections with ramps the complicated traffic fl...

  20. Improving traffic flow at a 2-to-1 lane reduction with wirelessly connected, adaptive cruise control vehicles

    Davis, L. C.

    2016-06-01

    Wirelessly connected vehicles that exchange information about traffic conditions can reduce delays caused by congestion. At a 2-to-1 lane reduction, the improvement in flow past a bottleneck due to traffic with a random mixture of 40% connected vehicles is found to be 52%. Control is based on connected-vehicle-reported velocities near the bottleneck. In response to indications of congestion the connected vehicles, which are also adaptive cruise control vehicles, reduce their speed in slowdown regions. Early lane changes of manually driven vehicles from the terminated lane to the continuous lane are induced by the slowing connected vehicles. Self-organized congestion at the bottleneck is thus delayed or eliminated, depending upon the incoming flow magnitude. For the large majority of vehicles, travel times past the bottleneck are substantially reduced. Control is responsible for delaying the onset of congestion as the incoming flow increases. Adaptive cruise control increases the flow out of the congested state at the bottleneck. The nature of the congested state, when it occurs, appears to be similar under a variety of conditions. Typically 80-100 vehicles are approximately equally distributed between the lanes in the 500 m region prior to the end of the terminated lane. Without the adaptive cruise control capability, connected vehicles can delay the onset of congestion but do not increase the asymptotic flow past the bottleneck. Calculations are done using the Kerner-Klenov three-phase theory, stochastic discrete-time model for manual vehicles. The dynamics of the connected vehicles is given by a conventional adaptive cruise control algorithm plus commanded deceleration. Because time in the model for manual vehicles is discrete (one-second intervals), it is assumed that the acceleration of any vehicle immediately in front of a connected vehicle is constant during the time interval, thereby preserving the computational simplicity and speed of a discrete-time model.

  1. Traffic flow modeling: a Genealogy

    Van Wageningen-Kessels, F.L.M.; Hoogendoorn, S.P.; Vuik, C.; Lint, van J. W. C.

    2014-01-01

    80 years ago, Bruce Greenshields presented the first traffic flow model at the Annual Meeting of the Highway Research Board. Since then, many models and simulation tools have been developed. We show a model tree with four families of traffic flow models, all descending from Greenshields' model. The tree shows the historical development of traffic flow modeling and the relations between models. Based on the tree we discuss the main trends and future developments in traffic flow modeling and si...

  2. Physics of Traffic Flow

    Davis, L. C.

    2015-03-01

    The Texas A&M Transportation Institute estimated that traffic congestion cost the United States 121 billion in 2011 (the latest data available). The cost is due to wasted time and fuel. In addition to accidents and road construction, factors contributing to congestion include large demand, instability of high-density free flow and selfish behavior of drivers, which produces self-organized traffic bottlenecks. Extensive data collected on instrumented highways in various countries have led to a better understanding of traffic dynamics. From these measurements, Boris Kerner and colleagues developed a new theory called three-phase theory. They identified three major phases of flow observed in the data: free flow, synchronous flow and wide moving jams. The intermediate phase is called synchronous because vehicles in different lanes tend to have similar velocities. This congested phase, characterized by lower velocities yet modestly high throughput, frequently occurs near on-ramps and lane reductions. At present there are only two widely used methods of congestion mitigation: ramp metering and the display of current travel-time information to drivers. To find more effective methods to reduce congestion, researchers perform large-scale simulations using models based on the new theories. An algorithm has been proposed to realize Wardrop equilibria with real-time route information. Such equilibria have equal travel time on alternative routes between a given origin and destination. An active area of current research is the dynamics of connected vehicles, which communicate wirelessly with other vehicles and the surrounding infrastructure. These systems show great promise for improving traffic flow and safety.

  3. Online traffic flow model applying dynamic flow-density relation

    This dissertation describes a new approach of the online traffic flow modelling based on the hydrodynamic traffic flow model and an online process to adapt the flow-density relation dynamically. The new modelling approach was tested based on the real traffic situations in various homogeneous motorway sections and a motorway section with ramps and gave encouraging simulation results. This work is composed of two parts: first the analysis of traffic flow characteristics and second the development of a new online traffic flow model applying these characteristics. For homogeneous motorway sections traffic flow is classified into six different traffic states with different characteristics. Delimitation criteria were developed to separate these states. The hysteresis phenomena were analysed during the transitions between these traffic states. The traffic states and the transitions are represented on a states diagram with the flow axis and the density axis. For motorway sections with ramps the complicated traffic flow is simplified and classified into three traffic states depending on the propagation of congestion. The traffic states are represented on a phase diagram with the upstream demand axis and the interaction strength axis which was defined in this research. The states diagram and the phase diagram provide a basis for the development of the dynamic flow-density relation. The first-order hydrodynamic traffic flow model was programmed according to the cell-transmission scheme extended by the modification of flow dependent sending/receiving functions, the classification of cells and the determination strategy for the flow-density relation in the cells. The unreasonable results of macroscopic traffic flow models, which may occur in the first and last cells in certain conditions are alleviated by applying buffer cells between the traffic data and the model. The sending/receiving functions of the cells are determined dynamically based on the classification of the

  4. Simulation of traffic flow at a signalised intersection

    Foulaadvand, M. Ebrahim; Belbaasi, Sommayeh

    2008-01-01

    We have developed a Nagel-Schreckenberg cellular automata model for describing of vehicular traffic flow at a single intersection. A set of traffic lights operating either in fixed-time or traffic adaptive scheme controls the traffic flow. Closed boundary condition is applied to the streets each of which conduct a uni-directional flow. Extensive Monte Carlo simulations are carried out to find the model characteristics. In particular, we investigate the dependence of the flows on the signalisa...

  5. Simulation of traffic flow at a signalised intersection

    Foulaadvand, M Ebrahim

    2008-01-01

    We have developed a Nagel-Schreckenberg cellular automata model for describing of vehicular traffic flow at a single intersection. A set of traffic lights operating either in fixed-time or traffic adaptive scheme controls the traffic flow. Closed boundary condition is applied to the streets each of which conduct a uni-directional flow. Extensive Monte Carlo simulations are carried out to find the model characteristics. In particular, we investigate the dependence of the flows on the signalisation parameters.

  6. Traffic flow modeling: a Genealogy

    Van Wageningen-Kessels, F.L.M.; Hoogendoorn, S.P.; Vuik, C.; Van Lint, J.W.C.

    2014-01-01

    80 years ago, Bruce Greenshields presented the first traffic flow model at the Annual Meeting of the Highway Research Board. Since then, many models and simulation tools have been developed. We show a model tree with four families of traffic flow models, all descending from Greenshields' model. The

  7. Probabilistic description of traffic flow

    A stochastic description of traffic flow, called probabilistic traffic flow theory, is developed. The general master equation is applied to relatively simple models to describe the formation and dissolution of traffic congestions. Our approach is mainly based on spatially homogeneous systems like periodically closed circular rings without on- and off-ramps. We consider a stochastic one-step process of growth or shrinkage of a car cluster (jam). As generalization we discuss the coexistence of several car clusters of different sizes. The basic problem is to find a physically motivated ansatz for the transition rates of the attachment and detachment of individual cars to a car cluster consistent with the empirical observations in real traffic. The emphasis is put on the analogy with first-order phase transitions and nucleation phenomena in physical systems like supersaturated vapour. The results are summarized in the flux-density relation, the so-called fundamental diagram of traffic flow, and compared with empirical data. Different regimes of traffic flow are discussed: free flow, congested mode as stop-and-go regime, and heavy viscous traffic. The traffic breakdown is studied based on the master equation as well as the Fokker-Planck approximation to calculate mean first passage times or escape rates. Generalizations are developed to allow for on-ramp effects. The calculated flux-density relation and characteristic breakdown times coincide with empirical data measured on highways. Finally, a brief summary of the stochastic cellular automata approach is given

  8. Two dimensional mixed traffic flow considering the transit traffic

    Lingjiang Kong; Junhui Hu; Li Yang

    2012-01-01

    Based on the two-dimension cellular automaton traffic flow model (BML model), a mixed traffic flow model for urban traffic considering the transit traffic is established in this paper by using the Don't block the box rules. We have investigated the influences of the transit traffic ratio, and found that, in most cases, the urban traffic flow exhibited jam phase. Moreover, focusing on the traffic lights cycle, it is found that the average flow has the periodic fluctuation phenomenon, and we ha...

  9. Linearized Theory of Traffic Flow

    Cohan, Tal

    2014-01-01

    The equation of motion of a general class of macroscopic traffic flow models is linearized around a steady uniform flow. A closed-form solution of a boundary-initial value problem is obtained, and it is used to describe several phenomena. Specifically, the scenarios examined involve a smooth velocity field in stop-and-go traffic, a discontinuous velocity field with shock waves in a traffic light problem, and discontinuous displacement fields in a problem where a single platoon of vehicles splits into two, and later merges back into one.

  10. Two dimensional mixed traffic flow considering the transit traffic

    Lingjiang Kong

    2012-12-01

    Full Text Available Based on the two-dimension cellular automaton traffic flow model (BML model, a mixed traffic flow model for urban traffic considering the transit traffic is established in this paper by using the Don't block the box rules. We have investigated the influences of the transit traffic ratio, and found that, in most cases, the urban traffic flow exhibited jam phase. Moreover, focusing on the traffic lights cycle, it is found that the average flow has the periodic fluctuation phenomenon, and we have explained this periodical oscillation change under different boundary conditions. The comparison to practical measured data shows that our stimulation results are accordant with the changes of real traffic flow, which confirms the accuracy and rationality of our model.

  11. Web application for traffic flow forecasting

    Dubravac, Dragan

    2015-01-01

    Disturbances in traffic on highways usually lead to an increase in traffic flow density or even traffic jams. The main goal of the diploma thesis is to produce an application that will predict traffic flow and traffic jams on any given date and time based on traffic flow in the past. By using an estimated desired speed the traffic information gained from flow counters we can forecast the evolution of traffic jams. The application presents a graph that represents the number of vehicles on a...

  12. Traffic Flow Management and Optimization

    Rios, Joseph Lucio

    2014-01-01

    This talk will present an overview of Traffic Flow Management (TFM) research at NASA Ames Research Center. Dr. Rios will focus on his work developing a large-scale, parallel approach to solving traffic flow management problems in the national airspace. In support of this talk, Dr. Rios will provide some background on operational aspects of TFM as well a discussion of some of the tools needed to perform such work including a high-fidelity airspace simulator. Current, on-going research related to TFM data services in the national airspace system and general aviation will also be presented.

  13. Traffic Data and Their Implications for Consistent Traffic Flow Modeling

    Helbing, Dirk

    1998-01-01

    The paper analyzes traffic data of the Dutch freeway A9 with respect to certain aspects which are relevant for traffic flow modeling as well as the calibration of model parameters and functions. Apart from the dynamic velocity distribution, the density-dependence and the temporal evolution of various, partly lane-specific quantities is investigated. The results are well compatible with recent macroscopic traffic flow models which have been derived from the dynamics of driver-vehicle units. Th...

  14. Deep Learning Predictors for Traffic Flows

    Polson, Nicholas; Sokolov, Vadim

    2016-01-01

    We develop a deep learning predictor for modeling traffic flows. The challenge arises as traffic flows have sharp nonlinearities resulting from transitions from free flow to breakdown and then to congested flow. Our methodology uses a deep learning architecture to capture nonlinear spatio-temporal flow effects. We show how traffic flow data, from road sensors, can be predicted using deep learning. For comparison, we use a benchmark sparse $\\ell_1$ trend filter and we illustrate our methodolog...

  15. Empirical Phase Diagram of Congested Traffic Flow

    Lee, H. Y.; Lee, H. -W.; Kim, D.

    1999-01-01

    We present an empirical phase diagram of the congested traffic flow measured on a highway section with one effective on-ramp. Through the analysis of local density-flow relations and global spatial structure of the congested region, four distinct congested traffic states are identified. These states appear at different levels of the upstream flux and the on-ramp flux, thereby generating a phase digram of the congested traffic flow. Observed traffic states are discussed in connection with rece...

  16. Empirical analysis of heterogeneous traffic flow

    Ambarwati, L.; Pel, A.J.; Verhaeghe, R.J.; Van Arem, B.

    2013-01-01

    Traffic flow in many developing countries is strongly mixed comprising vehicle types, such as motorcycles, cars, (mini) buses, and trucks; furthermore, traffic flow typically exhibits free inter-lane exchanges. This phenomenon causes a complex vehicle interaction, rendering most existing traffic flo

  17. Traffic Flow Models and Their Numerical Solutions

    Jin, Wenlong

    2004-01-01

    In this thesis, Riemann problems and Godunov methods are developed for higher order traffic flow models. A rigorous analysis of the first order traffic flow model of inhomogeneous road is presented. A two-level simulation framework of network vehicular traffic is proposed as a Godunov-type finite difference system with the supply-demand method as an alternative of Riemann solver.

  18. IMPROVING VEHICLE FLOW WITH TRAFFIC LIGHTS

    J. POLI; L. H. A. Monteiro

    2005-01-01

    A probabilistic cellular automata is used for investigating how a traffic light placed on a street intersection influences vehicle velocities. Numerical simulations reveal that above a critical density of cars, the traffic light improves the flow in both directions.

  19. Particle hopping models and traffic flow theory

    Nagel, Kai

    1995-01-01

    This paper shows how particle hopping models fit into the context of traffic flow theory. Connections between fluid-dynamical traffic flow models, which derive from the Navier-Stokes-equations, and particle hopping models are shown. In some cases, these connections are exact and have long been established, but have never been viewed in the context of traffic theory. In other cases, critical behavior of traffic jam clusters can be compared to instabilities in the partial differential equations...

  20. Traffic flow optimization on roundabouts

    Delle Monache, Maria Laura; Obsu, Legesse Lemecha; Goatin, Paola; Kassa, Semu Mitiku

    2013-01-01

    The aim of this paper is to optimize the traffic flow on roundabouts using a macroscopic approach. The roundabout is modeled as a sequence of 2x2 junctions: with one mainline and secondary incoming and outgoing roads. We consider two cost functionals: the total travel time and the total waiting time, which give an estimate of the time spent by drivers on the network section. These cost functionals are minimized analytically for each junction with respect to the right of way parameter of the i...

  1. Traffic Flow Prediction Using MI Algorithm and Considering Noisy and Data Loss Conditions: An Application to Minnesota Traffic Flow Prediction

    Hosseini, Seyed Hadi; Moshiri, Behzad; Rahimi-Kian, Ashkan; Nadjar Araabi, Babak

    2014-01-01

    Traffic flow forecasting is useful for controlling traffic flow, traffic lights, and travel times. This study uses a multi-layer perceptron neural network and the mutual information (MI) technique to forecast traffic flow and compares the prediction results with conventional traffic flow forecasting methods. The MI method is used to calculate the interdependency of historical traffic data and future traffic flow. In numerical case studies, the proposed traffic flow forecasting method was test...

  2. Predicting Information Flows in Network Traffic.

    Hinich, Melvin J.; Molyneux, Robert E.

    2003-01-01

    Discusses information flow in networks and predicting network traffic and describes a study that uses time series analysis on a day's worth of Internet log data. Examines nonlinearity and traffic invariants, and suggests that prediction of network traffic may not be possible with current techniques. (Author/LRW)

  3. Robust Traffic Flow Management: Coevolutionary Approach Project

    National Aeronautics and Space Administration — We will develop a Coevolutionary Decision Support Tool (CDST) that explicitly incorporates weather uncertainty (non-probabilistically) into strategic Traffic Flow...

  4. Temporal Characteristics of Large IP Traffic Flows

    Abrahamsson, Henrik; Ahlgren, Bengt

    2003-01-01

    Several studies of Internet traffic have shown that it is a small percentage of the flows that dominate the traffic. This is often referred to as the mice and elephants phenomenon. It has been proposed that this might be one of very few invariants of Internet traffic and that this property could somehow be used for traffic engineering purposes. The idea being that one in a scalable way could control a major part of the traffic by only keeping track of a small number of flows. But for this the...

  5. Traffic flow wide-area surveillance system definition

    Allgood, G.O.; Ferrell, R.K.; Kercel, S.W.; Abston, R.A.; Carnal, C.L. [Oak Ridge National Lab., TN (United States); Moynihan, P.I. [Jet Propulsion Lab., Pasadena, CA (United States)

    1994-11-01

    Traffic Flow Wide-Area Surveillance (TFWAS) is a system for assessing the state of traffic flow over a wide area for enhanced traffic control and improved traffic management and planning. The primary purpose of a TFWAS system is to provide a detailed traffic flow description and context description to sophisticated traffic management and control systems being developed or envisioned for the future. A successful TFWAS system must possess the attributes of safety, reconfigurability, reliability, and expandability. The primary safety premise of TFWAS is to ensure that no action or failure of the TFWAS system or its components can result in risk of injury to humans. A wide variety of communication techniques is available for use with TFWAS systems. These communication techniques can be broken down into two categories, landlines and wireless. Currently used and possible future traffic sensing technologies have been examined. Important criteria for selecting TFWAS sensors include sensor capabilities, costs, operational constraints, sensor compatibility with the infrastructure, and extent. TFWAS is a concept that can take advantage of the strengths of different traffic sensing technologies, can readily adapt to newly developed technologies, and can grow with the development of new traffic control strategies. By developing innovative algorithms that will take information from a variety of sensor types and develop descriptions of traffic flows over a wide area, a more comprehensive understanding of the traffic state can be provided to the control system to perform the most reasonable control actions over the entire wide area. The capability of characterizing the state of traffic over an entire region should revolutionize developments in traffic control strategies.

  6. Traffic Flow Management Wrap-Up

    Grabbe, Shon

    2011-01-01

    Traffic Flow Management involves the scheduling and routing of air traffic subject to airport and airspace capacity constraints, and the efficient use of available airspace. Significant challenges in this area include: (1) weather integration and forecasting, (2) accounting for user preferences in the Traffic Flow Management decision making process, and (3) understanding and mitigating the environmental impacts of air traffic on the environment. To address these challenges, researchers in the Traffic Flow Management area are developing modeling, simulation and optimization techniques to route and schedule air traffic flights and flows while accommodating user preferences, accounting for system uncertainties and considering the environmental impacts of aviation. This presentation will highlight some of the major challenges facing researchers in this domain, while also showcasing recent innovations designed to address these challenges.

  7. Traffic and Granular Flow ’07

    Chevoir, François; Gondret, Philippe; Lassarre, Sylvain; Lebacque, Jean-Patrick; Schreckenberg, Michael

    2009-01-01

    This book covers several research fields, all of which deal with transport. Three main topics are treated: road traffic, granular matter, and biological transport. Different points of view, i.e. modelling, simulations, experiments, and phenomenological observations, are considered. Sub-topics include: highway or urban vehicular traffic (dynamics of traffic, macro/micro modelling, measurements, data analysis, security issues, psychological issues), pedestrian traffic, animal traffic (e.g. social insects), collective motion in biological systems (molecular motors...), granular flow (dense flows, intermittent flows, solid/liquid transition, jamming, force networks, fluid and solid friction), networks (biological networks, urban traffic, the internet, vulnerability of networks, optimal transport networks) and cellular automata applied to the various aforementioned fields.

  8. Adaptive Traffic Signalization Model using Neuro-Fuzzy Controllers

    Devesh Batra; Pragya Verma

    2014-01-01

    Current traffic lights are pre-programmed and use daily signal timing schedules, which contribute to traffic congestion and delay. Thus, with the increase in the number of vehicles on road, need for adaptive signal technology arises which has the potential to adjust the timing of red, yellow and green lights in order to accommodate changing traffic patterns and ease traffic congestion. In this paper, we present a model for adaptive traffic signalization, which uses fuzzy neura...

  9. Fastlane: Traffic flow modeling and multi-class dynamic traffic management

    Schreiter, T.; Van Wageningen-Kessels, F.L.M.; Yuan, Y; Lint, van J. W. C.; Hoogendoorn, S.P.

    2012-01-01

    Dynamic Traffic Management (DTM) aims to improve traffic conditions. DTM usually consists of two steps: first the current traffic is estimated, then appropriate control actions are determined based on that estimate. In order to estimate and control the traffic, a suitable traffic flow model that reproduces the properties of traffic well must be used. One of the most important properties is that traffic is composed of multiple vehicle classes. While many traffic flow models have been proposed ...

  10. Traffic and Granular Flow ’03

    Luding, Stefan; Bovy, Piet; Schreckenberg, Michael; Wolf, Dietrich

    2005-01-01

    These proceedings are the fifth in the series Traffic and Granular Flow, and we hope they will be as useful a reference as their predecessors. Both the realistic modelling of granular media and traffic flow present important challenges at the borderline between physics and engineering, and enormous progress has been made since 1995, when this series started. Still the research on these topics is thriving, so that this book again contains many new results. Some highlights addressed at this conference were the influence of long range electric and magnetic forces and ambient fluids on granular media, new precise traffic measurements, and experiments on the complex decision making of drivers. No doubt the “hot topics” addressed in granular matter research have diverged from those in traffic since the days when the obvious analogies between traffic jams on highways and dissipative clustering in granular flow intrigued both c- munities alike. However, now just this diversity became a stimulating feature of the ...

  11. Real-Time Corrected Traffic Correlation Model for Traffic Flow Forecasting

    Lu, Hua-pu; Sun, Zhi-yuan; Qu, Wen-cong; Wang, Ling

    2015-01-01

    This paper focuses on the problems of short-term traffic flow forecasting. The main goal is to put forward traffic correlation model and real-time correction algorithm for traffic flow forecasting. Traffic correlation model is established based on the temporal-spatial-historical correlation characteristic of traffic big data. In order to simplify the traffic correlation model, this paper presents correction coefficients optimization algorithm. Considering multistate characteristic of traffic ...

  12. Spatiotemporal traffic-flow dependency and short-term traffic forecasting

    Yang Yue; Anthony Gar-On Yeh

    2008-01-01

    Short-term traffic forecasting is playing an increasing role in modern transport management. Although many short-term traffic forecasting methods have been explored, the spatiotemporal dependency of traffic flow, an important characteristic of traffic dynamics that can benefit the forecasting of traffic changes, is often neglected in short-term traffic forecasting. This paper first investigates the spatiotemporal dependency of traffic flow using cross-correlation analysis and then discusses i...

  13. Traffic flow dynamics data, models and simulation

    Treiber, Martin

    2013-01-01

    This textbook provides a comprehensive and instructive coverage of vehicular traffic flow dynamics and modeling. It makes this fascinating interdisciplinary topic, which to date was only documented in parts by specialized monographs, accessible to a broad readership. Numerous figures and problems with solutions help the reader to quickly understand and practice the presented concepts. This book is targeted at students of physics and traffic engineering and, more generally, also at students and professionals in computer science, mathematics, and interdisciplinary topics. It also offers material for project work in programming and simulation at college and university level. The main part, after presenting different categories of traffic data, is devoted to a mathematical description of the dynamics of traffic flow, covering macroscopic models which describe traffic in terms of density, as well as microscopic many-particle models in which each particle corresponds to a vehicle and its driver. Focus chapters on ...

  14. International Workshop on Traffic and Granular Flow

    Herrmann, Hans; Schreckenberg, Michael; Wolf, Dietrich; Social, Traffic and Granular Dynamics

    2000-01-01

    "Are there common phenomena and laws in the dynamic behavior of granular materials, traffic, and socio-economic systems?" The answers given at the international workshop "Traffic and Granular Flow '99" are presented in this volume. From a physical standpoint, all these systems can be treated as (self)-driven many-particle systems with strong fluctuations, showing multistability, phase transitions, non-linear waves, etc. The great interest in these systems is due to several unexpected new discoveries and their practical relevance for solving some fundamental problems of today's societies. This includes intelligent measures for traffic flow optimization and methods from "econophysics" for stabilizing (stock) markets.

  15. Traffic and Granular Flow '11

    Buslaev, Alexander; Bugaev, Alexander; Yashina, Marina; Schadschneider, Andreas; Schreckenberg, Michael; TGF11

    2013-01-01

    This book continues the biannual series of conference proceedings, which has become a classical reference resource in traffic and granular research alike. It addresses new developments at the interface between physics, engineering and computational science. Complex systems, where many simple agents, be they vehicles or particles, give rise to surprising and fascinating phenomena.   The contributions collected in these proceedings cover several research fields, all of which deal with transport. Topics include highway, pedestrian and internet traffic, granular matter, biological transport, transport networks, data acquisition, data analysis and technological applications. Different perspectives, i.e. modeling, simulations, experiments and phenomenological observations, are considered.

  16. The Effects of Taxi on Traffic Flow

    Tang, Tie-Qiao; Li, Yan; Huang, Hai-Jun

    Taxi will come to one complete halt during the boarding/alighting period and might produce stop-and-go without passengers, so it often produces traffic interruption on the single-lane system. Tang et al. pointed out that the traffic flow model [Chin. Phys. 18, 975 (2009)] can be used to directly describe various micro phenomena resulted by traffic interruption on the single-lane system, if we properly define the traffic interruption probability, so in this paper we adopt this model to study the micro phenomena resulted by taxi on the single-lane system. The numerical results show that this model can describe the effects that taxi has on the trails of each vehicle's motion and the evolutions of the flow and the density on the single-lane system, but that these effects are relevant to the initial conditions of the whole system.

  17. Fastlane: Traffic flow modeling and multi-class dynamic traffic management

    Schreiter, T.; Van Wageningen-Kessels, F.L.M.; Yuan, Y.; Van Lint, J.W.C.; Hoogendoorn, S.P.

    2012-01-01

    Dynamic Traffic Management (DTM) aims to improve traffic conditions. DTM usually consists of two steps: first the current traffic is estimated, then appropriate control actions are determined based on that estimate. In order to estimate and control the traffic, a suitable traffic flow model that rep

  18. Maximizing Quality and Performance of Network Through Adaptive Traffic Engineering

    Sameera Pallavi; Ch.Sandeep; P.Pramod Kumar

    2013-01-01

    Network management systems are to handle traffic dynamics in order to ensure congestion free network with highest throughput. IP environments are able to provide simple facilities for forwarding and routing packets. However, in presence of dynamic traffic conditions efficient management of resources is yet to be achieved. Recently Ning Wang et al. proposed a traffic engineering system which can ynamically adapt to traffic conditions with the help of virtual routing topologies. It has two majo...

  19. A superstatistical model of vehicular traffic flow

    Kosun, Caglar; Ozdemir, Serhan

    2016-02-01

    In the analysis of vehicular traffic flow, a myriad of techniques have been implemented. In this study, superstatistics is used in modeling the traffic flow on a highway segment. Traffic variables such as vehicular speeds, volume, and headway were collected for three days. For the superstatistical approach, at least two distinct time scales must exist, so that a superposition of nonequilibrium systems assumption could hold. When the slow dynamics of the vehicle speeds exhibit a Gaussian distribution in between the fluctuations of the system at large, one speaks of a relaxation to a local equilibrium. These Gaussian distributions are found with corresponding standard deviations 1 /√{ β }. This translates into a series of fluctuating beta values, hence the statistics of statistics, superstatistics. The traffic flow model has generated an inverse temperature parameter (beta) distribution as well as the speed distribution. This beta distribution has shown that the fluctuations in beta are distributed with respect to a chi-square distribution. It must be mentioned that two distinct Tsallis q values are specified: one is time-dependent and the other is independent. A ramification of these q values is that the highway segment and the traffic flow generate separate characteristics. This highway segment in question is not only nonadditive in nature, but a nonequilibrium driven system, with frequent relaxations to a Gaussian.

  20. A new dynamics model for traffic flow

    2001-01-01

    As a study method of traffic flow, dynamics models were developedand applied in the last few decades. However, there exist some flaws in most existing models. In this note, a new dynamics model is proposed by using car-following theory and the usual connection method of micro-macro variables, which can overcome some ubiquitous problems in the existing models. Numerical results show that the new model can very well simulate traffic flow conditions, such as congestion, evacuation of congestion, stop-and-go phenomena and phantom jam.

  1. Adaptive Traffic Signalization Model using Neuro-Fuzzy Controllers

    Devesh Batra*

    2014-07-01

    Full Text Available Current traffic lights are pre-programmed and use daily signal timing schedules, which contribute to traffic congestion and delay. Thus, with the increase in the number of vehicles on road, need for adaptive signal technology arises which has the potential to adjust the timing of red, yellow and green lights in order to accommodate changing traffic patterns and ease traffic congestion. In this paper, we present a model for adaptive traffic signalization, which uses fuzzy neural network for designing traffic signal controller. The controllers use vehicle detectors in order to detect the number of incoming vehicles. Based on the number of approaching vehicles, the current signal phase is either extended or terminated. The traffic volume at one particular region in an intersection is compared with that in the competing regions of the same intersection. The decision made is thus robust and results in less congestion and delays.

  2. Traffic Flow Wide-Area Surveillance system

    Allgood, G.O.; Ferrell, R.K.; Kercel, S.W.; Abston, R.A.

    1994-09-01

    Traffic management can be thought of as a stochastic queuing process where the serving time at one of its control points is dynamically linked to the global traffic pattern, which is, in turn, dynamically linked to the control point. For this closed-loop system to be effective, the traffic management system must sense and interpret a large spatial projection of data originating from multiple sensor suites. This concept is the basis for the development of a Traffic Flow Wide-Area Surveillance (TFWAS) system. This paper presents the results of a study by Oak Ridge National Laboratory to define the operational specifications and characteristics, to determine the constraints, and to examine the state of technology of a TFWAS system in terms of traffic management and control. In doing so, the functions and attributes of a TFWAS system are mapped into an operational structure consistent with the Intelligent Vehicle Highway System (IVHS) concept and the existing highway infrastructure. This mapping includes identifying candidate sensor suites and establishing criteria, requirements, and performance measures by which these systems can be graded in their ability and practicality to meet the operational requirements of a TFWAS system. In light of this, issues such as system integration, applicable technologies, impact on traffic management and control, and public acceptance are addressed.

  3. Modeling and Simulation of a Traffic Flow Model Considering the Influence of Traffic Interruption

    Yang, Shu-hong; Li, Chui-Gui; Xia, Dong-Xue; Wang, Meng; Wang, Xiao-Rong

    2013-01-01

    In this paper, we present a new lattice model of traffic flow by considering the effects of traffic interruption probability. The stability condition of the proposed model is obtained by employing the linear stability theory. The results show that the stability of traffic flow is improved by considering the influence of traffic interruption. Applying the method of nonlinear analysis, the modified Korteweg-de Vries (mKdV) equation is derived to describe the traffic behavior near the critical p...

  4. An ontology for traffic flow management

    Putten, Bart-Jan van; Wolfe, S.R.; Dignum, M.V.

    2008-01-01

    The Next Generation Air Transportation System (NGATS) project is a multi-faceted research effort to address issues with the National Airspace System. One such facet is the area of Collaborative Traffic Flow Management (CTFM), which intends to increase both the efficiency of the National Airspace System and the satisfaction level of the airlines.

  5. Traffic Flow Control In Automated Highway Systems

    Alvarez, Luis; Horowitz, Roberto

    1997-01-01

    This report studies the problem of traffic control in the Automated Highway System (AHS) hierarchical architecture of the California PATH program. A link layer controller for the PATH AHS architecture is presented. It is shown that the proposed control laws stabilize the vehicular density and flow around predetermined profiles.

  6. Dynamic Adaptation of the Traffic Management System CarDemo

    Cordier, A.; Domingues, Rémi; Labaere, Anthony; Noel, Nicolas; Thiery, Adrien; Cerqueus, Thomas; Perry, Philip; Ventresque, Anthony; et al.

    2014-01-01

    This paper demonstrates how we applied a constraint-based dynamic adaptation approach on CarDemo, a traffic management system. The approach allows domain experts to describe the adaptation goals as declarative constraints, and automatically plan the adaptation decisions to satisfy these constraints. We demonstrate how to utilise this approach to realise the dynamic switch of routing services of the traffic management system, according to the change of global system states and user requests.

  7. Forecasting multivariate road traffic flows using Bayesian dynamic graphical models, splines and other traffic variables

    Anacleto Junior, Osvaldo; Queen, Catriona; Albers, Casper

    2013-01-01

    Traffic flow data are routinely collected for many networks worldwide. These invariably large data sets can be used as part of a traffic management system, for which good traffic flow forecasting models are crucial. The linear multiregression dynamic model (LMDM) has been shown to be promising for forecasting flows, accommodating multivariate flow time series, while being a computationally simple model to use. While statistical flow forecasting models usually base their forecasts on flow da...

  8. Flow Detection Based on Traffic Video Image Processing

    Peng Shen

    2013-10-01

    Full Text Available Because in the traffic video image processing, the background image gotten from background modeling by traditional k-means clustering algorithm shows a lot of noises, thus the improvement of k-means clustering algorithm is proposed, and has been applied to the vehicle flow detection of traffic video image. By analyzing the vehicle detection method and comparing the flow detection algorithm, the improved k-means clustering algorithm is experimentally tested at last, and carries out software implementation. The experiment shows that the improved algorithm after background modeling is superior to the traditional one in time complexity, it has better adaptivity and robustness, which has increased the effect of vehicle flow detection.

  9. Characteristics of ant-inspired traffic flow: Applying the social insect metaphor to traffic models

    John, Alexander; Schadschneider, Andreas; Chowdhury, Debashish; Nishinari, Katsuhiro

    2009-01-01

    We investigate the organization of traffic flow on preexisting uni- and bidirectional ant trails. Our investigations comprise a theoretical as well as an empirical part. We propose minimal models of uni- and bi-directional traffic flow implemented as cellular automata. Using these models, the spatio-temporal organization of ants on the trail is studied. Based on this, some unusual flow characteristics which differ from those known from other traffic systems, like vehicular traffic or pedestri...

  10. Multi Model Criteria for the Estimation of Road Traffic Congestion from Traffic Flow Information Based on Fuzzy Logic

    K.Ram Mohan Rao; P. L. N. Raju; Hari Shankar

    2012-01-01

    In this study, the road traffic congestion of Dehradun city is evaluated from traffic flow information using fuzzy techniques. Three different approaches namely Sugeno, Mamdani models which are manually tuned techniques, and an Adaptive Neuo-Fuzzy Inference System (ANFIS) which an automated model decides the ranges and parameters of the membership functions using grid partition technique, based on fuzzy logic. The systems are designed to human’s feelings on inputs and output levels. There are...

  11. From Traffic Flow to Economic System

    Bando, M.

    The optimal velocity model which is applied to traffic flow phenomena explains a spontaneous formation of traffic congestion. We discuss why the model works well in describing both free-flow and congested flow states in a unified way. The essential ingredient is that our model takes account of a sort of time delay in reacting to a given stimulus. This causes instability of many-body system, and yields a kind of phase transition above a certain critical density. Especially there appears a limit cycle on the phase space along which individual vehicle moves, and they show cyclic behavior. Once that we recognize the mechanism the same idea can be applied to a variety of phenomena which show cyclic behavior observed in many-body systems. As an example of such applications, we investigate business cycles commonly observed in economic system. We further discuss a possible origin of a kind of cyclic behavior observed in climate change.

  12. Analysis of vehicular traffic flow using a macroscopic model

    Pérez-Sánchez, Fernando Luis; Bautista, Alejandro; Salazar, Martin; Macias, Antonio

    2014-01-01

    Today the most cities in the world face different problems caused by vehicular traffic due to the increasing number of vehicles on road, such as traffic congestion, environmental pollution, excessive noise, increased accidents on the road, etc. Therefore it is important to represent the phenomenon by applying models so as to find better traffic flow patterns in a given city. In this work we introduce a simple macroscopic model to describe traffic flow in traffic congestion and we obtain the e...

  13. Adaptive Traffic Control Systems in a medium-sized Scandinavian city

    Agerholm, Niels; Olesen, Anne Vingaard

    2016-01-01

    Adaptive Traffic Control Systems (ATCS) are aimed at reducing congestion. ATCS adapt to approaching traffic to continuously optimise the traffic flows in question. ATCS have been implemented in many locations, including the Scandinavian countries, with various effects. Due to congestion problems......, ATCS were installed in the eight signalised intersections of a 1.7 km stretch of the ring road in the medium-sized Danish city of Aalborg. To measure the effect of ATCS a with/without study was carried out. GPS data from a car following the traffic, recorded transportation times for buses in service...... morning peak and midday off-peak. The effect on crossing and turning traffic was slight, and while reduced transportation time was found in one part of the ring road in another part transportation time was seen to increase. The benefit to the ring road was partly gained at the cost of slightly increased...

  14. Adaptive Queue Management with Restraint on Non-Responsive Flows

    Lan Li

    2003-12-01

    Full Text Available This paper proposes an adaptive queue management scheme (adaptive RED to improve Random Early Detection (RED on restraining non-responsive flows. Due to a lack of flow control mechanism, non-responsive flows can starve responsive flows for buffer and bandwidth at the gateway. In order to solve the disproportionate resource problem, RED framework is modified in this way: on detecting when the non-responsive flows starve the queue, packet-drop intensity (Max_p in RED can be adaptively adjusted to curb non-responsive flows for resource fair-sharing, such as buffer and bandwidth fair-sharing. Based on detection of traffic behaviors, intentionally restraining nonresponsive flows is to increase the throughput and decrease the drop rate of responsive flows. Our experimental results based on adaptive RED shows that the enhancement of responsive traffic and the better sharing of buffer and bandwidth can be achieved under a variety of traffic scenarios.

  15. Noise-Induced Phase Transition in Traffic Flow

    LIKe-Ping; GAOZi-You

    2004-01-01

    One of the dynamic phases of the traffic flow is the traffic jam. It appears in traffic flow when the vehicle density is larger than the critical value. In this paper, a new method is presented to investigate the traffic jam when the vehicle density is smaller than the critical value. In our method, we introduce noise into the traffic system after sufficient transient time. Under the effect of noise, the traffic jam appears, and the phase transition from free to synchronized flow occurs in traffic flow. Our method is tested for the deterministic NaSch traffic model. The simulation results demonstrate that there exist a broad range of lower densities at which the noise effect leading to traffic jam can be observed.

  16. Methods and systems of monitoring traffic flow

    Billington, Peter E.; Barnes, Christopher M.; Wakefield, Jonathan P.

    2001-01-01

    A method of monitoring traffic flow comprises reading registration plates of the vehicles of a multiplicity of series of vehicles passing respective locations on a road network, if necessary selecting samples of readings from the readings relating to the vehicles of the series, and determining whether readings of the samples are deemed to contain matching readings. The samples are used as probes or targets to measure average journey times which are compared with reference journey times. The s...

  17. Dynamics of bimodality in vehicular traffic flows

    Mullick, Arjun; Ray, Arnab K.

    2012-01-01

    A model equation has been proposed to describe bimodal features in vehicular traffic flows. The dynamics of the bimodal distribution reveals the existence of a fixed point that is connected to itself by a homoclinic trajectory. The mathematical conditions associated with bimodality have been established. The critical factors necessary for both a breaking of symmetry and a transition from bimodal to unimodal behaviour, in the manner of a bifurcation, have been analysed.

  18. Timing of traffic lights and phase separation in two-dimensional traffic flow

    Sun, Duo; Jiang, Rui; Wang, Bing-Hong

    2010-02-01

    In this paper, we study the effects of traffic light period in two-dimensional Biham-Middleton-Levine (BML) traffic flow model. It is found that a phase separation phenomenon, in which the system separates into coexistence of free flow and jam, could be observed in intermediate vehicle density range when traffic light period T⩾4. We have explained the reason of occurrence of phase separation and investigated its behavior in different traffic light period.

  19. Integrated Traffic Flow Management Decision Making

    Grabbe, Shon R.; Sridhar, Banavar; Mukherjee, Avijit

    2009-01-01

    A generalized approach is proposed to support integrated traffic flow management decision making studies at both the U.S. national and regional levels. It can consider tradeoffs between alternative optimization and heuristic based models, strategic versus tactical flight controls, and system versus fleet preferences. Preliminary testing was accomplished by implementing thirteen unique traffic flow management models, which included all of the key components of the system and conducting 85, six-hour fast-time simulation experiments. These experiments considered variations in the strategic planning look-ahead times, the replanning intervals, and the types of traffic flow management control strategies. Initial testing indicates that longer strategic planning look-ahead times and re-planning intervals result in steadily decreasing levels of sector congestion for a fixed delay level. This applies when accurate estimates of the air traffic demand, airport capacities and airspace capacities are available. In general, the distribution of the delays amongst the users was found to be most equitable when scheduling flights using a heuristic scheduling algorithm, such as ration-by-distance. On the other hand, equity was the worst when using scheduling algorithms that took into account the number of seats aboard each flight. Though the scheduling algorithms were effective at alleviating sector congestion, the tactical rerouting algorithm was the primary control for avoiding en route weather hazards. Finally, the modeled levels of sector congestion, the number of weather incursions, and the total system delays, were found to be in fair agreement with the values that were operationally observed on both good and bad weather days.

  20. Self-control of traffic lights and vehicle flows in urban road networks

    Lämmer, Stefan; Helbing, Dirk

    2008-04-01

    Based on fluid-dynamic and many-particle (car-following) simulations of traffic flows in (urban) networks, we study the problem of coordinating incompatible traffic flows at intersections. Inspired by the observation of self-organized oscillations of pedestrian flows at bottlenecks, we propose a self-organization approach to traffic light control. The problem can be treated as a multi-agent problem with interactions between vehicles and traffic lights. Specifically, our approach assumes a priority-based control of traffic lights by the vehicle flows themselves, taking into account short-sighted anticipation of vehicle flows and platoons. The considered local interactions lead to emergent coordination patterns such as 'green waves' and achieve an efficient, decentralized traffic light control. While the proposed self-control adapts flexibly to local flow conditions and often leads to non-cyclical switching patterns with changing service sequences of different traffic flows, an almost periodic service may evolve under certain conditions and suggests the existence of a spontaneous synchronization of traffic lights despite the varying delays due to variable vehicle queues and travel times. The self-organized traffic light control is based on an optimization and a stabilization rule, each of which performs poorly at high utilizations of the road network, while their proper combination reaches a superior performance. The result is a considerable reduction not only in the average travel times, but also of their variation. Similar control approaches could be applied to the coordination of logistic and production processes.

  1. A Multiagent Simulation for Traffic Flow Management with Evolutionary Optimization

    Filipiak, Patryk

    2011-01-01

    A traffic flow is one of the main transportation issues in nowadays industrialized agglomerations. Configuration of traffic lights is among the key aspects in traffic flow management. This paper proposes an evolutionary optimization tool that utilizes multiagent simulator in order to obtain accurate model. Even though more detailed studies are still necessary, a preliminary research gives an expectation for promising results.

  2. Simulation of Urban Traffic Flow Using Personal Experience of Drivers

    Mohammad-Reza Feizi-Derakhshi

    2011-08-01

    Full Text Available In recent years, with increasing population and number of private and public transport vehicles, traffic flow and its control, become a major and popular challenge. Working on control and simulation of traffic flow takes back to 20th century. In order to study and simulate traffic flow, we need to understand this issue and factors that cause congestion in the network and its problems. In recent years, researchers introduced novel methods to work with traffic flow. Those methods were intelligent models. Intelligent models inspired from nature and have some specific useful properties for controlling traffic rate. This paper introduced a new model that named Personal Experience of Driver (PED. Our method is an intelligent model for simulating traffic flow. This method modelsnatural behavior of drivers. Results show that this model properly simulates urban traffic flow based on personal experience of drivers.

  3. Traffic Flow Detection Based on Wireless Sensor Network

    Bao-juan Liang

    2013-01-01

    Detecting traffic flow by in-road inductive loop is the most common methods, but inductive loop is physically large, it is hard to install and maintain, also the classification rate is low. The inductive loops cannot communicate with each other, so they cannot share traffic data with each other. The wireless sensor network has these features: real-time, fault tolerance, scalability and coordination. Applying wireless sensor network into traffic area for traffic flow detection is easier to ins...

  4. Real-Time Corrected Traffic Correlation Model for Traffic Flow Forecasting

    Hua-pu Lu

    2015-01-01

    Full Text Available This paper focuses on the problems of short-term traffic flow forecasting. The main goal is to put forward traffic correlation model and real-time correction algorithm for traffic flow forecasting. Traffic correlation model is established based on the temporal-spatial-historical correlation characteristic of traffic big data. In order to simplify the traffic correlation model, this paper presents correction coefficients optimization algorithm. Considering multistate characteristic of traffic big data, a dynamic part is added to traffic correlation model. Real-time correction algorithm based on Fuzzy Neural Network is presented to overcome the nonlinear mapping problems. A case study based on a real-world road network in Beijing, China, is implemented to test the efficiency and applicability of the proposed modeling methods.

  5. From Cellular Attractor Selection to Adaptive Signal Control for Traffic Networks

    Tian, Daxin; Zhou, Jianshan; Sheng, Zhengguo; Wang, Yunpeng; Ma, Jianming

    2016-03-01

    The management of varying traffic flows essentially depends on signal controls at intersections. However, design an optimal control that considers the dynamic nature of a traffic network and coordinates all intersections simultaneously in a centralized manner is computationally challenging. Inspired by the stable gene expressions of Escherichia coli in response to environmental changes, we explore the robustness and adaptability performance of signalized intersections by incorporating a biological mechanism in their control policies, specifically, the evolution of each intersection is induced by the dynamics governing an adaptive attractor selection in cells. We employ a mathematical model to capture such biological attractor selection and derive a generic, adaptive and distributed control algorithm which is capable of dynamically adapting signal operations for the entire dynamical traffic network. We show that the proposed scheme based on attractor selection can not only promote the balance of traffic loads on each link of the network but also allows the global network to accommodate dynamical traffic demands. Our work demonstrates the potential of bio-inspired intelligence emerging from cells and provides a deep understanding of adaptive attractor selection-based control formation that is useful to support the designs of adaptive optimization and control in other domains.

  6. Stability analysis of traffic flow with extended CACC control models

    Ya-Zhou, Zheng; Rong-Jun, Cheng; Siu-Ming, Lo; Hong-Xia, Ge

    2016-06-01

    To further investigate car-following behaviors in the cooperative adaptive cruise control (CACC) strategy, a comprehensive control system which can handle three traffic conditions to guarantee driving efficiency and safety is designed by using three CACC models. In this control system, some vital comprehensive information, such as multiple preceding cars’ speed differences and headway, variable safety distance (VSD) and time-delay effect on the traffic current and the jamming transition have been investigated via analytical or numerical methods. Local and string stability criterion for the velocity control (VC) model and gap control (GC) model are derived via linear stability theory. Numerical simulations are conducted to study the performance of the simulated traffic flow. The simulation results show that the VC model and GC model can improve driving efficiency and suppress traffic congestion. Project supported by the National Natural Science Foundation of China (Grant Nos. 71571107 and 11302110). The Scientific Research Fund of Zhejiang Province, China (Grant Nos. LY15A020007, LY15E080013, and LY16G010003). The Natural Science Foundation of Ningbo City (Grant Nos. 2014A610030 and 2015A610299), the Fund from the Government of the Hong Kong Administrative Region, China (Grant No. CityU11209614), and the K C Wong Magna Fund in Ningbo University, China.

  7. Traffic Flow Control - Optimization on Horizon

    Homolová, Jitka

    Praha: ÚTIA AV ČR, 2006 - (Přikryl, J.; Šmídl, V.). s. 43-44 [International PhD Workshop on Interplay of Societal and Technical Decision - Making , Young Generation Viewpoint /7./. 25.09.2006-30.09.2006, Hrubá Skála] Grant ostatní: MD ČR(CZ) 1F43A/003/120 Institutional research plan: CEZ:AV0Z10750506 Keywords : linear programming * traffic flow control * control on horizon Subject RIV: BC - Control Systems Theory

  8. Decentralized and Tactical Air Traffic Flow Management

    Bertsimas, Dimitris; Odoni, Amedeo R.

    1997-01-01

    This project dealt with the following topics: 1. Review and description of the existing air traffic flow management system (ATFM) and identification of aspects with potential for improvement. 2. Identification and review of existing models and simulations dealing with all system segments (enroute, terminal area, ground) 3. Formulation of concepts for overall decentralization of the ATFM system, ranging from moderate decentralization to full decentralization 4. Specification of the modifications to the ATFM system required to accommodate each of the alternative concepts. 5. Identification of issues that need to be addressed with regard to: determination of the way the ATFM system would be operating; types of flow management strategies that would be used; and estimation of the effectiveness of ATFM with regard to reducing delay and re-routing costs. 6. Concept evaluation through identification of criteria and methodologies for accommodating the interests of stakeholders and of approaches to optimization of operational procedures for all segments of the ATFM system.

  9. Traffic Flow Detection Based on Wireless Sensor Network

    Bao-juan Liang

    2013-08-01

    Full Text Available Detecting traffic flow by in-road inductive loop is the most common methods, but inductive loop is physically large, it is hard to install and maintain, also the classification rate is low. The inductive loops cannot communicate with each other, so they cannot share traffic data with each other. The wireless sensor network has these features: real-time, fault tolerance, scalability and coordination. Applying wireless sensor network into traffic area for traffic flow detection is easier to install, and provide real-time traffic flow for coordinate traffic control, also it can improve the classification rate. A lot of researchers applied the wireless sensor network for traffic flow detection, but no one referred to the coordinate traffic flow detection method. In this paper, we provided a coordinate traffic flow detection framework. Based on this framework, we set up a simple traffic flow detection platform by wireless sensor nodes produced by cross box company to verify this method. We selected four periods, for each period, we got a more than 90% classification rate.

  10. Abnormal traffic flow data detection based on wavelet analysis

    Xiao Qian

    2016-01-01

    Full Text Available In view of the traffic flow data of non-stationary, the abnormal data detection is difficult.proposed basing on the wavelet analysis and least squares method of abnormal traffic flow data detection in this paper.First using wavelet analysis to make the traffic flow data of high frequency and low frequency component and separation, and then, combined with least square method to find abnormal points in the reconstructed signal data.Wavelet analysis and least square method, the simulation results show that using wavelet analysis of abnormal traffic flow data detection, effectively reduce the detection results of misjudgment rate and false negative rate.

  11. Characteristics of Vehicular Traffic Flow at a Roundabout

    Fouladvand, M. Ebrahim; Sadjadi, Zeinab; Shaebani, M. Reza

    2003-01-01

    We construct a stochastic cellular automata model for the description of vehicular traffic at a roundabout designed at the intersection of two perpendicular streets. The vehicular traffic is controlled by a self-organized scheme in which traffic lights are absent. This controlling method incorporates a yield-at-entry strategy for the approaching vehicles to the circulating traffic flow in the roundabout. Vehicular dynamics is simulated within the framework of the probabilistic cellular automa...

  12. Traffic Signals Control with Adaptive Fuzzy Controller in Urban Road Network

    LI Yan; FAN Xiao-ping

    2008-01-01

    An adaptive fuzzy logic controller (AFC) is presented for the signal control of the urban traffic network.The AFC is composed of the signal control system-oriented control level and the signal controller-oriented fuzzy rules regulation level.The control level decides the signal tunings in an intersection with a fuzzy logic controller.The regulation level optimizes the fuzzy rules by the Adaptive Rule Module in AFC according to both the system performance index in current control period and the traffic flows in the last one.Consequently the system performances are improved.A weight coefficient controller (WCC) is also developed to describe the interactions of traffic flow among the adjacent intersections.So the AFC combined with the WCC can be applied in a road network for signal timings.Simulations of the AFC on a real traffic scenario have been conducted.Simulation results indicate that the adaptive controller for traffic control shows better performance than the actuated one.

  13. EXPLAINING TRAFFIC FLOW PATTERNS USING CENTRALITY MEASURES

    Amila Jayasinghe

    2015-06-01

    Full Text Available This study examines the capability of centrality parameters of the road network to explain and predict traffic flow by types of vehicles. The case study was conducted in Colombo Metropolitan Area, Sri Lanka. Study used four centrality parameters i.e. connectivity, global integration, local integration and choice; and three analysis methods i.e. topological, metric and angular which introduced by space syntax analysis method to compute network centrality of the road network. Findings of this study stress that, (1 human beings perceive the space mostly from geometrical distance (topological and angular distance in comparison to metric distance. Further to this, it was found that angular distance is more powerful in global level whereas topological distance is more powerful in local level; (2 it is more appropriate to consider the multiple influences from multiple centrality parameters rather being confined to a single best parameter and influence of each parameter varies based on type of vehicles.

  14. Complementarity of Traffic Flow Intersecting Method with Intersection Capacity Analysis

    Lanović, Zdenko

    2009-01-01

    The paper studies the complementarity of the methods from the field of traffic flow theory: methods of traffic flow intersecting intensity and the method for the at-grade intersection capacity analysis. Apart from checking mutual implications of these methods, the proportionality of mutual influences is assessed. Harmonized application of these methods acts efficiently on the entire traffic network, and not only on the intersections that are usually incorrectly represented as the only network...

  15. A delayed flow intersection model for dynamic traffic assignment

    DURLIN, T; HENN, V

    2005-01-01

    Day-to-Day and Within-Day dynamics are classically observed in dynamic traffic assignment, but smaller ones due to traffic lights phases also occur. These micro variations induce flow fluctuations defined at a cycle time scale. Their precise knowledge is irrelevant in a dynamic traffic assignment context. We propose to integrate these micro dynamics into a new intersection model without stages in which their average effects must be taken into account, especially delay and flow restriction ge...

  16. Characteristics of vehicular traffic flow at a roundabout

    Ebrahim Fouladvand, M.; Sadjadi, Zeinab; Reza Shaebani, M.

    2004-10-01

    We construct a stochastic cellular automata model for the description of vehicular traffic at a roundabout designed at the intersection of two perpendicular streets. The vehicular traffic is controlled by a self-organized scheme in which traffic lights are absent. This controlling method incorporates a yield-at-entry strategy for the approaching vehicles to the circulating traffic flow in the roundabout. Vehicular dynamics is simulated and the delay experienced by the traffic at each individual street is evaluated. We discuss the impact of the geometrical properties of the roundabout on the total delay. We compare our results with traffic-light signalization schemes, and obtain the critical traffic volume over which the intersection is optimally controlled through traffic-light signalization schemes.

  17. Capacity of Multi-vehicle-types Mixed Traffic Flow

    LI Wen-quan; WANG Wei; DENG Wei

    2001-01-01

    Based on the gap acceptance theory, the mixed traffic flow composed of r representative typesflows on the unsignalized intersection is set up. It is an extension of capacity model for one type vehicletraffic flow, and it is very fitter to the Chinese highway traffic condition than the other models.

  18. A Realistic Cellular Automaton Model for Synchronized Traffic Flow

    ZHAO Bo-Han; HU Mao-Bin; JIANG Rui; WU Qing-Song

    2009-01-01

    A cellular automaton model is proposed to consider the anticipation effect in drivers' behavior. It is shown that the anticipation effect can be one of the origins of synchronized traffic flow. With anticipation effect, the congested traffic flow simulated by the model exhibits the features of synchronized flow. The spatiotemporal patterns induced by an on-ramp are also consistent with the three-phaee traffic theory. Since the origin of synchronized flow is still controversial, our work can shed some light on the mechanism of synchronized flow.

  19. Effect of violating the traffic light rule in the Biham-Middleton-Levine traffic flow model

    Ding, Zhong-Jun; Jiang, Rui; Li, Ming; Li, Qi-Lang; Wang, Bing-Hong

    2012-09-01

    This paper studies the effect of violating the traffic light rule in the Biham-Middleton-Levine (BML) traffic flow model. It is assumed that there are two kinds of drivers: normal drivers obey the traffic light rule and violators disobey it. Simulation results show that although the existence of violators increases the average velocity in the free-flowing phase, it decreases the threshold from free-flowing phase to jam. With the presence of violators, a new kind of configuration with stripe slopes -2 and -1/2 has been found in the free-flowing phase. We have developed an analytical investigation which successfully predicts the average velocity in the free-flowing phase. A phase separation phenomenon, where jams and freely flowing traffic coexist, has been found in the intermediate car density range. The mechanism of the phase separation has been illustrated.

  20. Impact of Road Bends on Traffic Flow in a Single-Lane Traffic System

    Zeng Junwei

    2014-01-01

    Full Text Available Taking the characteristics of road bends as a research object, this work proposes the cellular model (CA with road bends based on the NaSch model, with which the traffic flow is examined under different conditions, such as bend radius, bend arc length, and road friction coefficiency. The simulation results show that, with the increase of the bend radius, the peak flow will be continuously increased, and the fundamental diagram will become more similar to that of the classic NaSch model; the smaller the bend radius is, the easier it is for the occurrence of blockage; for different bend lengths, all the corresponding traffic flows show that the phenomenon of go-and-stop and the bends exert slight inhibitory effect on traffic flow; under the same bend radius, the inhibition effect of the bends on the traffic flow will be weakened with the increase of the friction coefficiency.

  1. Effects of Car Accidents on Three-Lane Traffic Flow

    Jianzhong Chen

    2014-01-01

    Full Text Available A three-lane traffic flow model is proposed to investigate the effect of car accidents on the traffic flow. The model is an extension of the full velocity difference (FVD model by taking into account the lane changing. The extended lane-changing rules are presented to model the lane-changing behaviour. The cases that the car accidents occupy the exterior or interior lane, the medium lane, and two lanes are studied by numerical simulations. The time-space diagrams and the current diagrams are presented, and the traffic jams are investigated. The results show that the car accident has a different effect on the traffic flow when it occupies different lanes. The car accidents have a more serious effect on the whole road when they occupy two lanes. The larger the density is, the greater the influence on the traffic flow becomes.

  2. Road traffic flow and impact on environment in Hyderabad city

    In Hyderabad city due to dramatic increase in traffic intensity on the roads, traffic flow have been much beyond the comfortable limits. High values of traffic flow density have been recorded on Court Road (34.05%), Tilak Road (19.87%), Risala Road (22.91%) and Cafe George (23.14%) of Hyderabad city. Above 80% people are found to be annoyed due to traffic congestion, noise and smoke resulting in health ailments. Slow Moving Vehicles (SMVs) comprising of animal and hand drawn vehicles (rehras) cause serious disruption in the traffic stream on city roads, which are ultimately causing traffic-jam condition resulting a serious impact on environment. No definite parking places exist for public vehicles because of encroachment on roads. Proper foot paths are not available for pedestrian, which results in increase in accidents. (author)

  3. Intervention and causality: forecasting traffic flows using a dynamic Bayesian network

    Queen, Catriona; Albers, Casper

    2009-01-01

    Real-time traffic flow data across entire networks can be used in a traffic management system to monitor current traffic flows so that traffic can be directed and managed efficiently. Reliable short-term forecasting models of traffic flows are crucial for the success of any traffic management system. The model proposed in this paper for forecasting traffic flows is a multivariate Bayesian dynamic model called the multiregression dynamic model (MDM). This model is an example of a dynamic ...

  4. Accurate Multisteps Traffic Flow Prediction Based on SVM

    Zhang Mingheng; Zhen Yaobao; Hui Ganglong; Chen Gang

    2013-01-01

    Accurate traffic flow prediction is prerequisite and important for realizing intelligent traffic control and guidance, and it is also the objective requirement for intelligent traffic management. Due to the strong nonlinear, stochastic, time-varying characteristics of urban transport system, artificial intelligence methods such as support vector machine (SVM) are now receiving more and more attentions in this research field. Compared with the traditional single-step prediction method, the mul...

  5. Microscopic modeling of multi-lane highway traffic flow

    Hodas, N O

    2003-01-01

    In heavy traffic with congested roadway the maximum traffic flow also depends on length of cars. This is deduced in a simple derivation suited for classroom demonstration as well as homework. The resulting equation demonstrates a new relation to an apparently unrelated area of physics, the maximum ship velocity (hull speed) and explains why traffic is sometimes faster on the slow lane on a congested multi-lane road.

  6. Various scales for traffic flow representation : Some reflections

    LESORT, JB; BOURREL, E; HENN, V

    2005-01-01

    This paper is an analysis of the various scales at which traffic flow can be represented, from vehicular to continuum flow models, with various time and space resolutions. The paper first investigates the question of scales and scale separation in traffic flow, both in modelling and measurement, using analogy with other disciplines. It then evaluates the representation of vehicles heterogeneities at various scales. It concludes on the interest of developing multiscale modeling. Keywords: tra...

  7. Traffic Flow. USMES Teacher's Resource Book, Preliminary Edition.

    Education Development Center, Inc., Newton, MA.

    This USMES unit challenges students to recommend and try to have a new road design or a system for rerouting traffic accepted so that cars and trucks can move safely at a reasonable speed through a busy intersection near the school. The teacher resource book for the Traffic Flow unit contains five sections. The first section describes the USMES…

  8. On short-term traffic flow forecasting and its reliability

    Abouaissa, Hassane; Fliess, Michel; Join, Cédric

    2016-01-01

    International audience Recent advances in time series, where deterministic and stochastic modelings as well as the storage and analysis of big data are useless, permit a new approach to short-term traffic flow forecasting and to its reliability, i.e., to the traffic volatility. Several convincing computer simulations, which utilize concrete data, are presented and discussed.

  9. The fundamental diagram : a macroscopic traffic flow model.

    Botma, H.

    1976-01-01

    In models of traffic flow, the interactions between vehicles are of prime interest, and are based on characteristics of the drivers, road and vehicles. The fundamental diagram is a representation of a relationship on a macroscopic level in the steady state between the quantity of traffic and a chara

  10. Revised lattice Boltzmann model for traffic flow with equilibrium traffic pressure

    Shi, Wei; Lu, Wei-Zhen; Xue, Yu; He, Hong-Di

    2016-02-01

    A revised lattice Boltzmann model concerning the equilibrium traffic pressure is proposed in this study to tackle the phase transition phenomena of traffic flow system. The traditional lattice Boltzmann model has limitation to investigate the complex traffic phase transitions due to its difficulty for modeling the equilibrium velocity distribution. Concerning this drawback, the equilibrium traffic pressure is taken into account to derive the equilibrium velocity distribution in the revised lattice Boltzmann model. In the proposed model, a three-dimensional velocity-space is assumed to determine the equilibrium velocity distribution functions and an alternative, new derivative approach is introduced to deduct the macroscopic equations with the first-order accuracy level from the lattice Boltzmann model. Based on the linear stability theory, the stability conditions of the corresponding macroscopic equations can be obtained. The outputs indicate that the stability curve is divided into three regions, i.e., the stable region, the neutral stability region, and the unstable region. In the stable region, small disturbance appears in the initial uniform flow and will vanish after long term evolution, while in the unstable region, the disturbance will be enlarged and finally leads to the traffic system entering the congested state. In the neutral stability region, small disturbance does not vanish with time and maintains its amplitude in the traffic system. Conclusively, the stability of traffic system is found to be enhanced as the equilibrium traffic pressure increases. Finally, the numerical outputs of the proposed model are found to be consistent with the recognized, theoretical results.

  11. Controlling Disorder in Traffic Flow by Perturbation

    LI Ke-Ping; GAO Zi-You; CHEN Tian-Lun

    2004-01-01

    We propose a new technique for controlling disorder in traffic system. A kind of control signal which can be considered as a perturbation has been designated at a given site (perturbation point) of the single-lane highway. When a vehicle passes the perturbation point at a time, the velocity of the vehicle will be changed at the next time by the perturbation. This technique is tested for the deterministic NaSch traffic model. The simulation results indicate that the traffic system can be transited from the disorder states to the order states, such as fixed-point, periodic motion, etc.

  12. Accurate Multisteps Traffic Flow Prediction Based on SVM

    Zhang Mingheng

    2013-01-01

    Full Text Available Accurate traffic flow prediction is prerequisite and important for realizing intelligent traffic control and guidance, and it is also the objective requirement for intelligent traffic management. Due to the strong nonlinear, stochastic, time-varying characteristics of urban transport system, artificial intelligence methods such as support vector machine (SVM are now receiving more and more attentions in this research field. Compared with the traditional single-step prediction method, the multisteps prediction has the ability that can predict the traffic state trends over a certain period in the future. From the perspective of dynamic decision, it is far important than the current traffic condition obtained. Thus, in this paper, an accurate multi-steps traffic flow prediction model based on SVM was proposed. In which, the input vectors were comprised of actual traffic volume and four different types of input vectors were compared to verify their prediction performance with each other. Finally, the model was verified with actual data in the empirical analysis phase and the test results showed that the proposed SVM model had a good ability for traffic flow prediction and the SVM-HPT model outperformed the other three models for prediction.

  13. Agent-Based Collaborative Traffic Flow Management Project

    National Aeronautics and Space Administration — We propose agent-based game-theoretic approaches for simulation of strategies involved in multi-objective collaborative traffic flow management (CTFM). Intelligent...

  14. An extended signal control strategy for urban network traffic flow

    Yan, Fei; Tian, Fuli; Shi, Zhongke

    2016-03-01

    Traffic flow patterns are in general repeated on a daily or weekly basis. To improve the traffic conditions by using the inherent repeatability of traffic flow, a novel signal control strategy for urban networks was developed via iterative learning control (ILC) approach. Rigorous analysis shows that the proposed learning control method can guarantee the asymptotic convergence. The impacts of the ILC-based signal control strategy on the macroscopic fundamental diagram (MFD) were analyzed by simulations on a test road network. The results show that the proposed ILC strategy can evenly distribute the accumulation in the network and improve the network mobility.

  15. Modelling Widely Scattered States in `Synchronized' Traffic Flow and Possible Relevance for Stock Market Dynamics

    Helbing, Dirk; Batic, Davide; Schoenhof, Martin; Treiber, Martin

    2001-01-01

    Traffic flow at low densities (free traffic) is characterized by a quasi-one-dimensional relation between traffic flow and vehicle density, while no such fundamental diagram exists for `synchronized' congested traffic flow. Instead, a two-dimensional area of widely scattered flow-density data is observed as a consequence of a complex traffic dynamics. For an explanation of this phenomenon and transitions between the different traffic phases, we propose a new class of molecular-dynamics-like, ...

  16. Vehicular Traffic Flow Controlled by Traffic Light on a Street with Open Boundaries

    Mhirech, Abdelaziz; Ismaili, Assia Alaoui

    2013-08-01

    The Nagel-Schreckenberg (NS) cellular automata (CA) model for describing the vehicular traffic flow in a street with open boundaries is studied. To control the traffic flow, a traffic signalization light operating for a fixed-time scheme is placed in the middle of the street. Extensive Monte Carlo simulations are carried out to calculate various model characteristics. Essentially, we investigate the formation of the cars queue behind traffic light dependence on the duration of green light Tg, injecting and extracting probabilities α and β, respectively. Two phases of average training queues were found. Besides, the dependence of car accident probability per site and per time step on Tg, α and β is computed.

  17. Traffic Flow States in a Freeway with Bottleneck

    PENG Zi-Hui; SUN Gang; ZHU Jing-Yi

    2009-01-01

    The system of mixture of single lane and double lane is studied by a cellular automata model, which is developed by us based on the Nagel and Schreckenberg's models. We justify that the model can reach a stable states quickly. The density distributions of the stable state is presented for several cases, which illustrate the manner of the congestion. The relationship between the outflow rate and the total number of vehicles and that between the outflow rate and the density just before the bottleneck are both given. Comparing with the relationship that occurring in the granular flow, we conclude that the transition from the free traffic flow to the congested traffic flow can also be attributed to the abrupt variation through unstable flow state, which can naturally explain the discontinuities and the complex time variation behavior observed in the traffic flow experiments.

  18. Nonequilibrium phase separation in traffic flows

    Hayakawa, H; Nakanishi, K.

    1997-01-01

    Traffic jam in an optimal velocity model with the backward reference function is analyzed. An analytic scaling solution is presented near the critical point of the phase separation. The validity of the solution has been confirmed from the comparison with the simulation of the model.

  19. Particle hopping vs. fluid-dynamical models for traffic flow

    Nagel, K.

    1995-12-31

    Although particle hopping models have been introduced into traffic science in the 19509, their systematic use has only started recently. Two reasons for this are, that they are advantageous on modem computers, and that recent theoretical developments allow analytical understanding of their properties and therefore more confidence for their use. In principle, particle hopping models fit between microscopic models for driving and fluiddynamical models for traffic flow. In this sense, they also help closing the conceptual gap between these two. This paper shows connections between particle hopping models and traffic flow theory. It shows that the hydrodynamical limits of certain particle hopping models correspond to the Lighthill-Whitham theory for traffic flow, and that only slightly more complex particle hopping models produce already the correct traffic jam dynamics, consistent with recent fluid-dynamical models for traffic flow. By doing so, this paper establishes that, on the macroscopic level, particle hopping models are at least as good as fluid-dynamical models. Yet, particle hopping models have at least two advantages over fluid-dynamical models: they straightforwardly allow microscopic simulations, and they include stochasticity.

  20. Adaptive multibeam concepts for traffic management satellite systems.

    Bisaga, J. J.; Blank, H. A.; Klein, S. A.

    1973-01-01

    The analysis of the performance of the various implementations of the simultaneous system in the Atlantic and Pacific Oceans has demonstrated that the use of adaptive system concepts in satellite traffic management systems can greatly improve the performance capabilities of these systems as compared to the corresponding performance capabilities of conventional nonadaptive satellite communications systems. It is considered that the techniques developed and analyzed represent a significant technological advance, and that the performance improvement achieved will generally outweigh the increased cost and implementation factors.

  1. Effect of Ad-Hoc Vehicular Network on Traffic Flow: Simulations in the Context of Three-Phase Traffic Theory

    Kerner, B. S.; Klenov, S. L.; Brakemeier, A.

    2009-01-01

    Effects of vehicle-to-vehicle (or/and vehicle-to-infrastructure communication, called also V2X communication)on traffic flow, which are relevant for ITS, are numerically studied. To make the study adequate with real measured traffic data, a testbed for wireless vehicle communication based on a microscopic model in the framework of three-phase traffic theory is developed and discussed. In this testbed, vehicle motion in traffic flow and analyses of a vehicle communication channel access based ...

  2. Two-phase bounded acceleration traffic flow model: Analytical solutions and applications

    LEBACQUE, JP

    2003-01-01

    The present paper describes a two phase traffic flow model. One phase is traffic equilibrium: flow and speed are functions of density, and traffic acceleration is low. The second phase is characterized by constant acceleration. This model extends first order traffic flow models and recaptures the fact that traffic acceleration is bounded. The paper show how to calculate analytical solutions of the two-phase model for dynamic traffic situations, provides a set of calculation rules, and analyze...

  3. Dynamical functional prediction and classification, with application to traffic flow prediction

    Chiou, Jeng-Min

    2013-01-01

    Motivated by the need for accurate traffic flow prediction in transportation management, we propose a functional data method to analyze traffic flow patterns and predict future traffic flow. In this study we approach the problem by sampling traffic flow trajectories from a mixture of stochastic processes. The proposed functional mixture prediction approach combines functional prediction with probabilistic functional classification to take distinct traffic flow patterns into account. The proba...

  4. Routing strategies in traffic network and phase transition in network traffic flow

    Bing-Hong Wang; Wen-Xu Wang

    2008-08-01

    The dynamics of information traffic over scale-free networks has been investigated systematically. A series of routing strategies of data packets have been proposed, including the local routing strategy, the next-nearest-neighbour routing strategy, and the mixed routing strategy based on local static and dynamic information. The capacity of the network can be quantified by the phase transition from free flow state to congestion state. The optimal parameter values of each model leading to the highest efficiency of scale-free networked traffic systems have been found. Moreover, we have found hysteretic loop in networked traffic systems with finite packets delivering ability. Such hysteretic loop indicates the existence of the bi-stable state in the traffic dynamics over scale-free networks.

  5. A Car-Following Theory for Multiphase Vehicular Traffic Flow

    Zhang, H. M.; Kim, T.(Yonsei University, Seoul, South Korea)

    2003-01-01

    We present in this paper a new car-following theory that can produce both the so-called capacity drop and traffic hysteresis, two prominent features of multiphase vehicular traffic flow. This is achieved through the introduction of a single variable, driver response time, that depends on both vehicle spacing and traffic phase. By specifying different functional forms of response time, one can obtain not only brand new theories but also some of the well-known old car-following theories, which ...

  6. Understanding and Modeling Driver Behavior in Dense Traffic Flow

    Zhang, H. Michael; Kim, T.

    2002-01-01

    We present in this report a new car-following theory that can reproduce both the so-called capacity drop and traffic hysteresis, two prominent features of multi-phase vehicular traffic flow. This is achieved through the introduction of a single variable, driver response time, that depends on both vehicle spacing and traffic motion. By specifying different functional forms of response time, one can obtain not only brand new theories but also some of the well-known old car-following theories, w...

  7. Influence of Darkness on Motorway Traffic Flow Characteristics

    Johnnie Ben-Edigbe

    2014-06-01

    Full Text Available The study is aimed at estimating the influence of darkness on motorways during dry weather. In a ‘with-and-without’ impact studies, motorway traffic flow characteristics at two different locations in Malaysia were investigated. Travel speed, traffic flow and headway data were obtained continuously for six weeks at selected sites and supplemented with darkness and daylight data culled from Malaysian Metrological Department website. Start of pitch darkness time was given as 19.45 pm. The study used 22:00 pm as start of pitch darkness. Results show that maximum flow rate, optimum travel speed, critical density and optimum headway did not differ significantly. The study concluded that motorway traffic flow characteristics are not influenced by darkness significantly.

  8. Effect of multi-velocity-difference in traffic flow

    Mo Ye-Liu; He Hong-Di; Xue Yu; Shi Wei; Lu Wei-Zhen

    2008-01-01

    Based on the optimal velocity models, an extended model is proposed, in which multi-velocity-difference ahead is taken into consideration. The damping effect of the multi-velocity-difference ahead has been investigated by means of analytical and numerical methods. Results indicate that the multi-velocity-difference leads to the enhancement of stability of traffic flow, suppression of the emergence of traffic jamming, and reduction of the energy consumption.

  9. Social dilemma structures hidden behind traffic flow with lane changes

    Aiming to merge traffic flow analysis with evolutionary game theory, we investigated the question of whether such structures can be formed from frequent lane changes in usual traffic flow without any explicit bottlenecks. In our model system, two classes of driver-agents coexist: C-agents (cooperative strategy) always remain in the lane they are initially assigned, whereas D-agents (defective strategy) try to change lanes to move ahead. In relatively high-density flows, such as the metastable and high-density phases, we found structures that correspond to either n-person prisoner dilemma (n-PD) games or quasi-PD games. In these situations, lane changes by D-agents create heavy traffic jams that reduce social efficiency. (paper)

  10. Comparative evaluations on dynamic simulation of foot traffic flows

    The evaluation and optimization of emergency route systems can be accomplished with different engineering methods. These methods are based on two different principles: the macroscopic and the microscopic approach. Both allow forecasting of evacuation times for various settings. In the work presented simple settings are investigated, consisting of rooms, corridor and stairs with regard to evacuation times and foot traffic flows. These calculations use current computer simulation programs, based on microscopic models, and the macroscopic method of Predtechenskii and Milinskii. For the computer simulation we use ASERI 3.4c, buildingEXODUS V4.0 Level 2, PedGo Version 2.1.1 and Simulex 11.1.3. The comparison of the results shows that even for the simplest systems the evacuation times and foot traffic flows vary considerably with different simulation programs and deviate from experimental results. Furthermore we investigate the effects of the boundary conditions on the foot traffic flow. (orig.)

  11. The effect of ACC vehicles to mixed traffic flow consisting of manual and ACC vehicles

    Xie Dong-Fan; Gao Zi-You; Zhao Xiao-Mei

    2008-01-01

    This paper studies the effect of adaptive cruise control (ACC) system on traffic flow by using simulations. The multiple headway and velocity difference (MHVD) model is used to depict the motion of ACC vehicles, and the simulation results are compared with the optimal velocity (OV) model which is used to depict the motion of manual vehicles.Compared the cases between the manual and the ACC vehicle flow, the fundamental diagram can be classified into four regions: I, II, III, IV. In low and high density the flux of the two models is the same; in region Ⅱ the free flow region of the MHVD model is enlarged, and the flux of the MHVD model is larger than that of the OV model; in region Ⅲ serious jams occur in the OV model while the ACC system suppresses the jams in the MHVD model and the traffic flow is in order, but the flux of the OV model is larger than that of the MHVD model. Similar phenomena also appeared in mixed traffic flow which consists of manual and ACC vehicles. The results indicate that ACC vehicles have significant effect on traffic flow. The improvement induced by ACC vehicles decreases with the increasing proportion of ACC vehicles.

  12. Estimation of the traffic noise level’s effect on the transit traffic flow in Krivoy Rog city

    Великодний, Денис; Звягінцев, Микола; Дьяченко, Вікторія

    2015-01-01

    It has been considered the influence of traffic noise taking into consideration the traffic flow, that should provide the impact of future noise sources and develop specific recommendations for further use in integrated schemes of organizing the transit traffic on urban highways.

  13. Macroscopic effects of reaction time on traffic flow characteristics

    Reaction time is defined as a physiological parameter reflecting the period of time between perceiving a stimulus and performing a relevant action. In the traffic flow theory literature, the effects of reaction time on string stability have been described using the microscopic modeling approach. This paper presents a distinct approach to investigate how reaction time influences traffic flow stability using a macroscopic model. In the paper, the distinction between string stability and flow stability is defined. The flow stability conditions are derived based on the macroscopic model, which is developed from a gas-kinetic principle. From linear analysis, we find that at macroscopic scale the reaction time influences how instabilities propagate but does not contribute to whether those (linear) instabilities occur. Nevertheless, nonlinear analysis might give a different view on the impact of reaction time on traffic flow stability, but the effect is nonlinear. We argue that the findings provide a better understanding of the effects of reaction time on traffic flow characteristics.

  14. Dynamic evaluation of traffic flows on city roads

    Quan Yongshen; Guo Jifu; Wen Huimin; Sun Jianping

    2012-01-01

    This paper presents an analysis of the random fluctuations, deferred conduction effect and periodicity of road traffic based on the basic features of road networks. It also discusses the limitations of road network evaluation theories based on road "V/C". In addition, it proposes a set of theoretical and technical methods for the real-time evaluation of traffic flows for entire road networks, and for solving key technical issues, such as real-time data collection and process- ing in areas with no blind zones, the spatial-temporal dynamic analysis of road network traffic, and the calibration of key performance index thresholds. It also provides new technical tools for the strategic transportation planning and real-time diagnosis of road traffic. The new tools and methodology presented in this paper are validated using a case study in Beijing.

  15. OPTIMIZATION OF URBAN MULTI-INTERSECTION TRAFFIC FLOW VIA Q-LEARNING

    Yit Kwong Chin; Heng Jin Tham; N.S.V. Kameswara Rao; Nurmin Bolong; Kenneth Tze Kin Teo

    2013-01-01

    Congestions of the traffic flow within the urban traffic network have been a challenging task for all the urban developers. Many approaches have been introduced into the current system to solve the traffic congestion problems. Reconfiguration of the traffic signal timing plan has been carried out through implementation of different techniques. However, dynamic characteristics of the traffic flow increase the difficulties towards the ultimate solutions. Thus, traffic congestions still remain a...

  16. Flow-aggregation Accelerating Strategy for TCP Traffic

    Xiaoguo Zhang

    2014-06-01

    Full Text Available A great number of researches on network flow characteristics show a large proportion of the network flows are single-packet flows. However, almost all existing flow termination strategies have no optimization for single-packet flows, so the efficiency of flow-aggregation is lower. Based on in-depth study of flow characteristics and TCP protocol specifications, we find the packet status, packet arrival interval and SYN packet size can identify single-packet flows accurately, and then propose a flow-aggregation accelerating strategy for TCP traffic that aims to quickly identify single-packet flows. We build efficiency model and accuracy model to compare our strategy performance with others and make a lot of experiments on the traces collected from a main channel in the CERNET during the latest five years. The results prove our strategy can greatly improve the efficiency of flow-aggregation at the cost of very little loss of accuracy

  17. OPTIMIZATION OF URBAN MULTI-INTERSECTION TRAFFIC FLOW VIA Q-LEARNING

    Yit Kwong Chin

    2013-01-01

    Full Text Available Congestions of the traffic flow within the urban traffic network have been a challenging task for all the urban developers. Many approaches have been introduced into the current system to solve the traffic congestion problems. Reconfiguration of the traffic signal timing plan has been carried out through implementation of different techniques. However, dynamic characteristics of the traffic flow increase the difficulties towards the ultimate solutions. Thus, traffic congestions still remain as unsolvable problems to the current traffic control system. In this study, artificial intelligence method has been introduced in the traffic light system to alter the traffic signal timing plan to optimize the traffic flows. Q-learning algorithm in this study has enhanced the traffic light system with learning ability. The learning mechanism of Q-learning enables traffic light intersections to release itself from traffic congestions situation. Adjacent traffic light intersections will work independently and yet cooperate with each others to a common goal of ensuring the fluency of the traffic flows within the traffic network. The simulated results show that the Q-Learning algorithm is able to learn from the dynamic traffic flow and optimize the traffic flow accordingly.

  18. Evolutionary Concepts for Decentralized Air Traffic Flow Management

    Adams, Milton; Kolitz, Stephan; Milner, Joseph; Odoni, Amedeo

    1997-01-01

    Alternative concepts for modifying the policies and procedures under which the air traffic flow management system operates are described, and an approach to the evaluation of those concepts is discussed. Here, air traffic flow management includes all activities related to the management of the flow of aircraft and related system resources from 'block to block.' The alternative concepts represent stages in the evolution from the current system, in which air traffic management decision making is largely centralized within the FAA, to a more decentralized approach wherein the airlines and other airspace users collaborate in air traffic management decision making with the FAA. The emphasis in the discussion is on a viable medium-term partially decentralized scenario representing a phase of this evolution that is consistent with the decision-making approaches embodied in proposed Free Flight concepts for air traffic management. System-level metrics for analyzing and evaluating the various alternatives are defined, and a simulation testbed developed to generate values for those metrics is described. The fundamental issue of modeling airline behavior in decentralized environments is also raised, and an example of such a model, which deals with the preservation of flight bank integrity in hub airports, is presented.

  19. Short-Term Traffic Flow Local Prediction Based on Combined Kernel Function Relevance Vector Machine Model

    Qichun Bing

    2015-01-01

    Full Text Available Short-term traffic flow prediction is one of the most important issues in the field of adaptive traffic control system and dynamic traffic guidance system. In order to improve the accuracy of short-term traffic flow prediction, a short-term traffic flow local prediction method based on combined kernel function relevance vector machine (CKF-RVM model is put forward. The C-C method is used to calculate delay time and embedding dimension. The number of neighboring points is determined by use of Hannan-Quinn criteria, and the CKF-RVM model is built based on genetic algorithm. Finally, case validation is carried out using inductive loop data measured from the north–south viaduct in Shanghai. The experimental results demonstrate that the CKF-RVM model is 31.1% and 52.7% higher than GKF-RVM model and GKF-SVM model in the aspect of MAPE. Moreover, it is also superior to the other two models in the aspect of EC.

  20. Three-phase theory of city traffic: Moving synchronized flow patterns in under-saturated city traffic at signals

    Kerner, Boris S.

    2014-03-01

    Three-phase traffic flow theory of city traffic has been developed. Based on simulations of a stochastic microscopic traffic flow model, features of moving synchronized flow patterns (MSP) have been studied, which are responsible for a random time-delayed breakdown of a green-wave (GW) organized in a city. A possibility of GW control leading to the prevention of GW breakdown has been demonstrated. A diagram of traffic breakdown in under-saturated traffic (transition from under- to over-saturated city traffic) at the signal has been found; the diagram presents regions of the average arrival flow rate, within which traffic breakdown can occur, in dependence of parameters of the time-function of the arrival flow rate or/and signal parameters. Physical reasons for a crucial difference between results of classical theory of city traffic and three-phase theory are explained. In particular, we have found that under-saturated traffic at the signal can exist during a long time interval, when the average arrival flow rate is larger than the capacity of the classical theory; the classical capacity is equal to a minimum capacity in three-phase theory. Within a range of the average arrival flow rate between the minimum and maximum signal capacities, under-saturated traffic is in a metastable state with respect to traffic breakdown. We have distinguished the following possible causes for the metastability of under-saturated traffic: (i) The arrival flow rate during the green phase is larger than the saturation flow rate. (ii) The length of the upstream front of a queue at the signal is a finite value. (iii) The outflow rate from a MSP (the rate of MSP discharge) is larger than the saturation flow rate.

  1. Adaptive network traffic management for multi user virtual environments

    Oliver, Iain Angus

    2011-01-01

    Multi User Virtual Environments (MUVE) are a new class of Internet application with a significant user base. This thesis adds to our understanding of how MUVE network traffic fits into the mix of Internet traffic, and how this relates to the application's needs. MUVEs differ from established Internet traffic types in their requirements from the network. They differ from traditional data traffic in that they have soft real-time constraints, from game traffic in that their bandwidth requi...

  2. Analysis of the stability and density waves for traffic flow

    薛郁

    2002-01-01

    In this paper, the optimal velocity model of traffic is extended to take into account the relative velocity. Thestability and density waves for traffic flow are investigated analytically with the perturbation method. The stabilitycriterion is derived by the linear stability analysis. It is shown that the triangular shock wave, soliton wave and kinkwave appear respectively in our model for density waves in the three regions: stable, metastable and unstable regions.These correspond to the solutions of the Burgers equation, Kortewegg-de Vries equation and modified Korteweg-de Vriesequation.The analytical results are confirmed to be in good agreement with those of numerical simulation. All theresults indicate that the interaction of a car with relative velocity can affect the stability of the traffic flow and raisecritical density.

  3. Traffic Flow Analysis Model based Routing Protocol For Multi-Protocol Label Switching Network

    E. R. Naganathan

    2011-01-01

    Full Text Available Problem statement: Multi-Protocol Label Switching (MPLS is a mechanism which is used in high-performance telecommunications networks that directs and carries data from one network node to the next with the help of labels. Traffic management is still an issue in MPLS network as it involves high speed internet. Approach: This study proposed a traffic flow analysis of the real time MPLS traffic and segregates the MPLS traffic as three major class based on the outcome of traffic flow analysis. Using the traffic class. This study proposed a reliable transmission methodology which provides traffic free routing in the MPLS networks. Results: The proposed traffic flow analysis based reliable routing model overcomes the network traffic and provides effective routing by offering traffic free path. Conclusion: The proposed traffic flow analysis model outperforms existing routing protocol and offers comparatively negligible packet loss.

  4. Towards reducing traffic congestion using cooperative adaptive cruise control on a freeway with a ramp

    Georges Arnaout

    2011-12-01

    Full Text Available Purpose: In this paper, the impact of Cooperative Adaptive Cruise Control (CACC systems on traffic performance is examined using microscopic agent-based simulation. Using a developed traffic simulation model of a freeway with an on-ramp - created to induce perturbations and to trigger stop-and-go traffic, the CACC system’s effect on the traffic performance is studied. The previously proposed traffic simulation model is extended and validated. By embedding CACC vehicles in different penetration levels, the results show significance and indicate the potential of CACC systems to improve traffic characteristics and therefore can be used to reduce traffic congestion. The study shows that the impact of CACC is positive but is highly dependent on the CACC market penetration. The flow rate of the traffic using CACC is proportional to the market penetration rate of CACC equipped vehicles and the density of the traffic.Design/methodology/approach: This paper uses microscopic simulation experiments followed by a quantitative statistical analysis. Simulation enables researchers manipulating the system variables to straightforwardly predict the outcome on the overall system, giving researchers the unique opportunity to interfere and make improvements to performance. Thus with simulation, changes to variables that might require excessive time, or be unfeasible to carry on real systems, are often completed within seconds.Findings: The findings of this paper are summarized as follow:•\tProvide and validate a platform (agent-based microscopic traffic simulator in which any CACC algorithm (current or future may be evaluated.•\tProvide detailed analysis associated with implementation of CACC vehicles on freeways.•\tInvestigate whether embedding CACC vehicles on freeways has a significant positive impact or not.Research limitations/implications: The main limitation of this research is that it has been conducted solely in a computer laboratory. Laboratory

  5. Traffic

    This chapter deals with passenger and freight traffic, public and private transportation, traffic related environmental impacts, future developments, traffic indicators, regional traffic planning, health costs due to road traffic related air pollution, noise pollution, measures and regulations for traffic control and fuels for traffic. In particular energy consumption, energy efficiency, pollutant emissions ( CO2, SO2, NOx, HC, CO, N2O, NH3 and particulates) and environmental effects of the different types of traffic and different types of fuels are compared and studied. Legal regulations and measures for an effective traffic control are discussed. (a.n.)

  6. Dynamic stochastic optimization models for air traffic flow management

    Mukherjee, Avijit

    This dissertation presents dynamic stochastic optimization models for Air Traffic Flow Management (ATFM) that enables decisions to adapt to new information on evolving capacities of National Airspace System (NAS) resources. Uncertainty is represented by a set of capacity scenarios, each depicting a particular time-varying capacity profile of NAS resources. We use the concept of a scenario tree in which multiple scenarios are possible initially. Scenarios are eliminated as possibilities in a succession of branching points, until the specific scenario that will be realized on a particular day is known. Thus the scenario tree branching provides updated information on evolving scenarios, and allows ATFM decisions to be re-addressed and revised. First, we propose a dynamic stochastic model for a single airport ground holding problem (SAGHP) that can be used for planning Ground Delay Programs (GDPs) when there is uncertainty about future airport arrival capacities. Ground delays of non-departed flights can be revised based on updated information from scenario tree branching. The problem is formulated so that a wide range of objective functions, including non-linear delay cost functions and functions that reflect equity concerns can be optimized. Furthermore, the model improves on existing practice by ensuring efficient use of available capacity without necessarily exempting long-haul flights. Following this, we present a methodology and optimization models that can be used for decentralized decision making by individual airlines in the GDP planning process, using the solutions from the stochastic dynamic SAGHP. Airlines are allowed to perform cancellations, and re-allocate slots to remaining flights by substitutions. We also present an optimization model that can be used by the FAA, after the airlines perform cancellation and substitutions, to re-utilize vacant arrival slots that are created due to cancellations. Finally, we present three stochastic integer programming

  7. Traffic Management as a Service: The Traffic Flow Pattern Classification Problem

    Carlos T. Calafate

    2015-01-01

    Full Text Available Intelligent Transportation System (ITS technologies can be implemented to reduce both fuel consumption and the associated emission of greenhouse gases. However, such systems require intelligent and effective route planning solutions to reduce travel time and promote stable traveling speeds. To achieve such goal these systems should account for both estimated and real-time traffic congestion states, but obtaining reliable traffic congestion estimations for all the streets/avenues in a city for the different times of the day, for every day in a year, is a complex task. Modeling such a tremendous amount of data can be time-consuming and, additionally, centralized computation of optimal routes based on such time-dependencies has very high data processing requirements. In this paper we approach this problem through a heuristic to considerably reduce the modeling effort while maintaining the benefits of time-dependent traffic congestion modeling. In particular, we propose grouping streets by taking into account real traces describing the daily traffic pattern. The effectiveness of this heuristic is assessed for the city of Valencia, Spain, and the results obtained show that it is possible to reduce the required number of daily traffic flow patterns by a factor of 4210 while maintaining the essence of time-dependent modeling requirements.

  8. The Development of the Multi-Center Traffic Management Advisor (MCTMA): Traffic Flow Management Research in a Multi-Facility Environment

    Lee, Katharine K.; Davis, Thomas J.; Levin, Kerry M.; Rowe, Dennis W.

    2001-01-01

    The Traffic Management Advisor (TMA) is a decision-support tool for traffic managers and air traffic controllers that provides traffic flow visualization and other flow management tools. TMA creates an efficiently sequenced and safely spaced schedule for arrival traffic that meets but does not exceed specified airspace system constraints. TMA is being deployed at selected facilities throughout the National Airspace System in the US as part of the FAA's Free Flight Phase 1 program. TMA development and testing, and its current deployment, focuses on managing the arrival capacity for single major airports within single terminal areas and single en route centers. The next phase of development for this technology is the expansion of the TMA capability to complex facilities in which a terminal area or airport is fed by multiple en route centers, thus creating a multicenter TMA functionality. The focus of the multi-center TMA (McTMA) development is on the busy facilities in the Northeast comdor of the US. This paper describes the planning and development of McTMA and the challenges associated with adapting a successful traffic flow management tool for a very complex airspace.

  9. Adaptive EWMA Method Based on Abnormal Network Traffic for LDoS Attacks

    Dan Tang

    2014-01-01

    Full Text Available The low-rate denial of service (LDoS attacks reduce network services capabilities by periodically sending high intensity pulse data flows. For their concealed performance, it is more difficult for traditional DoS detection methods to detect LDoS attacks; at the same time the accuracy of the current detection methods for LDoS attacks is relatively low. As the fact that LDoS attacks led to abnormal distribution of the ACK traffic, LDoS attacks can be detected by analyzing the distribution characteristics of ACK traffic. Then traditional EWMA algorithm which can smooth the accidental error while being the same as the exceptional mutation may cause some misjudgment; therefore a new LDoS detection method based on adaptive EWMA (AEWMA algorithm is proposed. The AEWMA algorithm which uses an adaptive weighting function instead of the constant weighting of EWMA algorithm can smooth the accidental error and retain the exceptional mutation. So AEWMA method is more beneficial than EWMA method for analyzing and measuring the abnormal distribution of ACK traffic. The NS2 simulations show that AEWMA method can detect LDoS attacks effectively and has a low false negative rate and a false positive rate. Based on DARPA99 datasets, experiment results show that AEWMA method is more efficient than EWMA method.

  10. Protection Over Asymmetric Channels, S-MATE: Secure Multipath Adaptive Traffic Engineering

    Aly, Salah A.; Ansari, Nirwan; Poor, H. Vincent; Walid, Anwar I.

    2010-01-01

    Several approaches have been proposed to the problem of provisioning traffic engineering between core network nodes in Internet Service Provider (ISP) networks. Such approaches aim to minimize network delay, increase capacity, and enhance security services between two core (relay) network nodes, an ingress node and an egress node. MATE (Multipath Adaptive Traffic Engineering) has been proposed for multipath adaptive traffic engineering between an ingress node (source) and an egress node (dest...

  11. S-MATE: Secure Coding-based Multipath Adaptive Traffic Engineering

    Aly, Salah A.; Ansari, Nirwan; Walid, Anwar I.; Poor, H. Vincent

    2010-01-01

    There have been several approaches to provisioning traffic between core network nodes in Internet Service Provider (ISP) networks. Such approaches aim to minimize network delay, increase network capacity, and enhance network security services. MATE (Multipath Adaptive Traffic Engineering) protocol has been proposed for multipath adaptive traffic engineering between an ingress node (source) and an egress node (destination). Its novel idea is to avoid network congestion and attacks that might e...

  12. Convergence of the Key Algorithm of Traffic-Flow Analysis

    Muka, László; Lencse, Gábor

    2006-01-01

    The traffic-flow analysis (TFA) [1] is a novel method for the performance estimation of communication systems. TFA contains an important algorithm called "correction for the finite capacity". The convergence of that algorithm is proven in this paper. The speed of convergence is also examined.

  13. Traffic Flow - USMES Teacher Resource Book. Fourth Edition. Trial Edition.

    Keskulla, Jean

    This Unified Sciences and Mathematics for Elementary Schools (USMES) unit challenges students to improve traffic flow at a problem location. The challenge is general enough to apply to many problem-solving situations in mathematics, science, social science, and language arts at any elementary school level (grades 1-8). The Teacher Resource Book…

  14. Continuum modelling of multi-lane heterogeneous traffic flow operations

    Hoogendoorn, S.P.; Bovy, P.H.L.

    1998-01-01

    This report represents the second report in regarding macroscopic traffic flow modelling. In this report we present a multiple lane generalisation of the aggregate-lane multiple user-class model. Key to its derivation is the lane-specific multiple user-class phase-space density (MUCPSD), generalisin

  15. Analytical studies on a new lattice hydrodynamic traffic flow model with consideration of traffic current cooperation among three consecutive sites

    Li, Zhipeng; Zhong, Chenjie; Chen, Lizhu; Xu, Shangzhi; Qian, Yeqing

    2016-09-01

    In this paper, the original lattice hydrodynamic model of traffic flow is extended to take into account the traffic current cooperation among three consecutive sites. The basic idea of the new consideration is that the cooperative traffic current of the considered site is determined by the traffic currents of the site itself, the immediately preceding site and the immediately following one. The stability criterion of the extended model is obtained by applying the linear stability analysis. The result reveals the traffic current cooperation of the immediately preceding site is positive correlation with the stability of traffic system, while negative correlation is found between the traffic stability and the traffic current cooperation of the nearest follow site. To describe the phase transition, the modified KdV equation near the critical point is derived by using the reductive perturbation method, with obtaining the dependence of the propagation kink solution for traffic jams on the traffic current cooperation among three consecutive sites. The direct numerical are conducted to verify the results of theoretical analysis, and explore the effects of the traffic current cooperation on the traffic flux of the vehicle flow system.

  16. Equivalent noise level response to number of vehicles: a comparison between a high traffic flow and low traffic flow highway in Klang Valley, Malaysia

    Halim, Herni; Abdullah, Ramdzani

    2014-01-01

    HIGHLIGHTS Highway traffic noise is a serious problem in Malaysia Heavy traffic flow highway recorded higher noise level compared to low traffic flow Noise level stabilized at certain number of vehicles on the road i.e above 500 vehicles. Although much research on road traffic noise has found that noise level increase are influenced by driver behavior and source-receiver distance, little attention has been paid to the relationship between noise level and total number of vehicles...

  17. Impact of Distracted Driving on Safety and Traffic Flow

    Stavrinos, Despina; Jones, Jennifer L.; Garner, Annie A.; Griffin, Russell; Franklin, Crystal A.; Ball, David; Welburn, Sharon C.; Ball, Karlene K.; Sisiopiku, Virginia P.; Philip R. Fine

    2013-01-01

    Studies have documented a link between distracted driving and diminished safety; however, an association between distracted driving and traffic congestion has not been investigated in depth. The present study examined the behavior of teens and young adults operating a driving simulator while engaged in various distractions (i.e., cell phone, texting, and undistracted) and driving conditions (i.e., free flow, stable flow, and oversaturation). Seventy five participants 16 to 25 years of age (sp...

  18. A Modified Cellular Automaton Model for Traffic Flow

    葛红霞; 董力耘; 雷丽; 戴世强

    2004-01-01

    A modified cellular automaton model for traffic flow was proposed. A novel concept about the changeable security gap was introduced and a parameter related to the variable security gap was determined. The fundamental diagram obtained by simulation shows that the maximum flow more approaches to the observed data than that of the NaSch model, indicating that the presented model is more reasonable and realistic.

  19. Cellular automata for traffic flow simulation with safety embedded notions

    Larraga, M. E.; Alvarez-Icaza, L.

    2007-01-01

    In this paper a cellular automata model for one-lane traffic flow is presented. A new set of rules is proposed to better capture driver reactions to traffic that are intended to preserve safety on the highway. As a result, drivers behavior is derived from an analysis that determines the most appropriate action for a vehicle based on the distance from the vehicle ahead of it and the velocities of the two neighbor vehicles. The model preserves simplicity of CA rules and at the same time makes t...

  20. An Adaptive Traffic Control System Using Raspberry PI

    S. Lokesh; , T.Prahlad Reddy

    2014-01-01

    By increasing of population the usage of vehicles have been increasing and controlling of traffic is one of the challenging works. The frequent traffic jams at major junctions call for an efficient traffic management system in place. The resulting wastage of time and increase in pollution levels can be eliminated on a city-wide scale by these systems. Previously the traffic control techniques used like magnetic loop detectors, induction loop detectors are buried on the road si...

  1. Automatic Incident Classification for Big Traffic Data by Adaptive Boosting SVM

    Wang, Li-li; Ngan, Henry Y. T.; Yung, Nelson H. C.

    2015-01-01

    Modern cities experience heavy traffic flows and congestions regularly across space and time. Monitoring traffic situations becomes an important challenge for the Traffic Control and Surveillance Systems (TCSS). In advanced TCSS, it is helpful to automatically detect and classify different traffic incidents such as severity of congestion, abnormal driving pattern, abrupt or illegal stop on road, etc. Although most TCSS are equipped with basic incident detection algorithms, they are however cr...

  2. Improved 2D Intelligent Driver Model simulating synchronized flow and evolution concavity in traffic flow

    Tian, Junfang; Li, Geng; Treiber, Martin; Zhu, Chenqiang; Jia, Bin

    2016-01-01

    This paper firstly show that 2 Dimensional Intelligent Driver Model (Jiang et al., PloS one, 9(4), e94351, 2014) is not able to replicate the synchronized traffic flow. Then we propose an improved model by considering the difference between the driving behaviors at high speeds and that at low speeds. Simulations show that the improved model can reproduce the phase transition from synchronized flow to wide moving jams, the spatiotemporal patterns of traffic flow induced by traffic bottleneck, and the evolution concavity of traffic oscillations (i.e. the standard deviation of the velocities of vehicles increases in a concave/linear way along the platoon). Validating results show that the empirical time series of traffic speed obtained from Floating Car Data can be well simulated as well.

  3. Cloud-based large-scale air traffic flow optimization

    Cao, Yi

    The ever-increasing traffic demand makes the efficient use of airspace an imperative mission, and this paper presents an effort in response to this call. Firstly, a new aggregate model, called Link Transmission Model (LTM), is proposed, which models the nationwide traffic as a network of flight routes identified by origin-destination pairs. The traversal time of a flight route is assumed to be the mode of distribution of historical flight records, and the mode is estimated by using Kernel Density Estimation. As this simplification abstracts away physical trajectory details, the complexity of modeling is drastically decreased, resulting in efficient traffic forecasting. The predicative capability of LTM is validated against recorded traffic data. Secondly, a nationwide traffic flow optimization problem with airport and en route capacity constraints is formulated based on LTM. The optimization problem aims at alleviating traffic congestions with minimal global delays. This problem is intractable due to millions of variables. A dual decomposition method is applied to decompose the large-scale problem such that the subproblems are solvable. However, the whole problem is still computational expensive to solve since each subproblem is an smaller integer programming problem that pursues integer solutions. Solving an integer programing problem is known to be far more time-consuming than solving its linear relaxation. In addition, sequential execution on a standalone computer leads to linear runtime increase when the problem size increases. To address the computational efficiency problem, a parallel computing framework is designed which accommodates concurrent executions via multithreading programming. The multithreaded version is compared with its monolithic version to show decreased runtime. Finally, an open-source cloud computing framework, Hadoop MapReduce, is employed for better scalability and reliability. This framework is an "off-the-shelf" parallel computing model

  4. Speed limit and ramp meter control for traffic flow networks

    Goatin, Paola; Göttlich, Simone; Kolb, Oliver

    2016-07-01

    The control of traffic flow can be related to different applications. In this work, a method to manage variable speed limits combined with coordinated ramp metering within the framework of the Lighthill-Whitham-Richards (LWR) network model is introduced. Following a 'first-discretize-then-optimize' approach, the first order optimality system is derived and the switch of speeds at certain fixed points in time is explained, together with the boundary control for the ramp metering. Sequential quadratic programming methods are used to solve the control problem numerically. For application purposes, experimental setups are presented wherein variable speed limits are used as a traffic guidance system to avoid traffic jams on highway interchanges and on-ramps.

  5. Network Traffic Anomalies Detection and Identification with Flow Monitoring

    Nguyen, Huy; Kim, Dong Il; Choi, Deokjai

    2010-01-01

    Network management and security is currently one of the most vibrant research areas, among which, research on detecting and identifying anomalies has attracted a lot of interest. Researchers are still struggling to find an effective and lightweight method for anomaly detection purpose. In this paper, we propose a simple, robust method that detects network anomalous traffic data based on flow monitoring. Our method works based on monitoring the four predefined metrics that capture the flow statistics of the network. In order to prove the power of the new method, we did build an application that detects network anomalies using our method. And the result of the experiments proves that by using the four simple metrics from the flow data, we do not only effectively detect but can also identify the network traffic anomalies.

  6. An Intelligent Traffic Flow Control System Based on Radio Frequency Identification and Wireless Sensor Networks

    Kuei-Hsiang Chao; Pi-Yun Chen

    2014-01-01

    This study primarily focuses on the use of radio frequency identification (RFID) as a form of traffic flow detection, which transmits collected information related to traffic flow directly to a control system through an RS232 interface. At the same time, the sensor analyzes and judges the information using an extension algorithm designed to achieve the objective of controlling the flow of traffic. In addition, the traffic flow situation is also transmitted to a remote monitoring control syste...

  7. Concept definition of traffic flow wide-area surveillance

    Allgood, G.O.; Ferrell, R.K.; Kercel, S.W.

    1994-07-01

    Traffic management can be thought of as a stochastic queuing process where the serving time at one of its control points is dynamically linked to the global traffic pattern, which is, in turn, dynamically linked to the control point. For this closed-loop system to be effective, the traffic management system must sense and interpret large spatial projections of data originating from multiple sensor suites. The intent of the Wide-Area Surveillance (WAS) Project is to build upon this concept and define the operational specifications and characteristics of a Traffic Flow Wide-Area Surveillance (TFWAS) system in terms of traffic management and control. In doing so, the functional capabilities of a TFWAS will be mapped onto an operational profile that is consistent with the Federal Highway Administration`s Intelligent Vehicle Highway System. This document provides the underlying foundation of this work by offering a concept definition for the TFWAS system. It concentrates on answering the question: ``What is the system?`` In doing so, the report develops a hierarchy of specialized definitions.

  8. Bayesian analysis of traffic flow on interstate I-55: The LWR model

    Polson, Nicholas; Sokolov, Vadim

    2014-01-01

    Transportation departments take actions to manage traffic flow and reduce travel times based on estimated current and projected traffic conditions. Travel time estimates and forecasts require information on traffic density which are combined with a model to project traffic flow such as the Lighthill–Whitham–Richards (LWR) model. We develop a particle filtering and learning algorithm to estimate the current traffic density state and the LWR parameters. These inputs are related to the so-called...

  9. Optimization of congested traffic flow in systems with a localized periodic inhomogeneity

    Tomer, Elad; Safonov, Leonid; Madar, Nilly; Havlin, Shlomo

    2001-01-01

    We study traffic flow on roads with a localized periodic inhomogeneity such as traffic signals, using a stochastic car-following model. We find that in cases of congestion, traffic flow can be optimized by controlling the inhomogeneity's frequency. By studying the wavelength dependence of the flux in stop-and-go traffic states, and exploring their stability, we are able to explain the optimization process. A general conclusion drawn from this study is, that the fundamental diagram of traffic ...

  10. Speed-Flow Analysis for Interrupted Oversaturated Traffic Flow with Heterogeneous Structure for Urban Roads

    Hemant Kumar Sharma

    2012-06-01

    Full Text Available Speed–flow functions have been developed by several transportation experts to predict accurately the speed of urban road network. HCM Speed-Flow Curve, BPR Curve, MTC Speed-Flow Curve, Akçelik Speed-Flow Curve are some extraordinary efforts to define the shape of speed-flow curve. However, the complexity of driver’s behaviour, interactions among different type of vehicles, lateral clearance, co-relation of driver’s psychology with vehicular characteristics and interdependence of various variables of traffic has led to continuous development and refinement of speed-flow curves. The problem gets more tedious in case of urban roads with heterogeneous traffic, oversaturated flow and signalized network (which includes some unsignalized intersections as well. This paper presents speed-flow analysis for urban roads with interrupted flow comprising of heterogeneous traffic. Model has been developed for heterogeneous traffic under constraints of roadway geometry, vehicle characteristics, driving behaviour and traffic controls. The model developed in this paper shall predict speed, delay, average queue and maximum queue estimates for urban roads and quantify congestion for oversaturated condition. The investigation details oversaturated portion of flow in particular.

  11. CONTROLLING TRAFFIC FLOW IN MULTILANE-ISOLATED INTERSECTION USING ANFIS APPROACH TECHNIQUES

    G. R. LAI; A. CHE SOH; H. MD. SARKAN; R. Z. ABDUL RAHMAN; Hassan, M. K.

    2015-01-01

    Many controllers have applied the Adaptive Neural-Fuzzy Inference System (ANFIS) concept for optimizing the controller performance. However, there are less traffic signal controllers developed using the ANFIS concept. ANFIS traffic signal controller with its fuzzy rule base and its ability to learn from a set of sample data could improve the performance of Existing traffic signal controlling system to reduce traffic congestions at most of the busy traffic intersections in city such as Kuala L...

  12. Impacts of different types of ramps on the traffic flow

    Nassab, K.; Schreckenberg, M.; Ouaskit, S.; Boulmakoul, A.

    2005-07-01

    The impact of the on- and off-ramps in a cellular automaton model for the traffic flow is studied. We include to the model the effect of spacing between the on- and the off-ramps on a same periodic road at a intersection (interchange) with another road. First, we use the Nagel-Schreckenberg (NaSch) model (J. Phys. I 2 (1992) 2221) without modifications to extract the basic phenomena of traffic flow, and in the following step we focus our investigation on the NaSch model with velocity-dependent randomization (VDR model) (Eur. Phys. J. B 5 (1998) 793) to examine the other system behaviors. Our results provide evidence that the metastable states and the phase separation can occur in the same way like in the models with local site defects.

  13. Splitting of Traffic Flows to Control Congestion in Special Events

    Ciro D'Apice; Rosanna Manzo; Luigi Rarità

    2011-01-01

    We deal with the optimization of traffic flows distribution at road junctions with an incoming road and two outgoing ones, in order to manage special events which determine congestion phenomena. Using a fluid-dynamic model for the description of the car densities evolution, the attention is focused on a decentralized approach. Two cost functionals, measuring the kinetic energy and the average travelling times, weighted with the number of cars moving on roads, are considered. The first one is ...

  14. Self-Adapting Routing Overlay Network for Frequently Changing Application Traffic in Content-Based Publish/Subscribe System

    Meng Chi; Shufen Liu; Changhong Hu

    2014-01-01

    In the large-scale distributed simulation area, the topology of the overlay network cannot always rapidly adapt to frequently changing application traffic to reduce the overall traffic cost. In this paper, we propose a self-adapting routing strategy for frequently changing application traffic in content-based publish/subscribe system. The strategy firstly trains the traffic information and then uses this training information to predict the application traffic in the future. Finally, the strat...

  15. An Adaptive Traffic Control System Using Raspberry PI

    S.Lokesh *

    2014-06-01

    Full Text Available By increasing of population the usage of vehicles have been increasing and controlling of traffic is one of the challenging works. The frequent traffic jams at major junctions call for an efficient traffic management system in place. The resulting wastage of time and increase in pollution levels can be eliminated on a city-wide scale by these systems. Previously the traffic control techniques used like magnetic loop detectors, induction loop detectors are buried on the road side provide the limited traffic information and require separate systems for traffic counting and for traffic surveillance. Here the project proposes to implement an artificial density traffic control system using image processing and Raspberrypi. The hardware here we are using is webcam, pc, Raspberry pi and the software used is OCCIDENTALIS and MATLAB. In this project the camera is get interfaced with a Raspberry pi. The image sequences from a camera are analyzed using thresholding method to find the density of vehicles. Subsequently, the number of vehicles at the intersection is evaluated and traffic is efficiently managed. In this project we implemented a real-time emergency vehicle detection system. In case an emergency vehicle is detected, the lane is given priority over all the others.

  16. Application of Chaos Theory in the Prediction of Motorised Traffic Flows on Urban Networks

    Aderemi Adewumi; Jimmy Kagamba; Alex Alochukwu

    2016-01-01

    In recent times, urban road networks are faced with severe congestion problems as a result of the accelerating demand for mobility. One of the ways to mitigate the congestion problems on urban traffic road network is by predicting the traffic flow pattern. Accurate prediction of the dynamics of a highly complex system such as traffic flow requires a robust methodology. An approach for predicting Motorised Traffic Flow on Urban Road Networks based on Chaos Theory is presented in this paper. No...

  17. The Study of Reinforcement Learning for Traffic Self-Adaptive Control under Multiagent Markov Game Environment

    Lun-Hui Xu; Xin-Hai Xia; Qiang Luo

    2013-01-01

    Urban traffic self-adaptive control problem is dynamic and uncertain, so the states of traffic environment are hard to be observed. Efficient agent which controls a single intersection can be discovered automatically via multiagent reinforcement learning. However, in the majority of the previous works on this approach, each agent needed perfect observed information when interacting with the environment and learned individually with less efficient coordination. This study casts traffic self-ad...

  18. An Adaptive Fuzzy-Logic Traffic Control System in Conditions of Saturated Transport Stream

    Marakhimov, A. R.; Igamberdiev, H. Z.; Umarov, Sh. X.

    2016-01-01

    This paper considers the problem of building adaptive fuzzy-logic traffic control systems (AFLTCS) to deal with information fuzziness and uncertainty in case of heavy traffic streams. Methods of formal description of traffic control on the crossroads based on fuzzy sets and fuzzy logic are proposed. This paper also provides efficient algorithms for implementing AFLTCS and develops the appropriate simulation models to test the efficiency of suggested approach. PMID:27517081

  19. Understanding Urban Traffic Flow Characteristics from the Network Centrality Perspective at Different Granularities

    Zhao, P. X.; Zhao, S. M.

    2016-06-01

    In this study, we analyze urban traffic flow using taxi trajectory data to understand the characteristics of traffic flow from the network centrality perspective at point (intersection), line (road), and area (community) granularities. The entire analysis process comprises three steps. The first step utilizes the taxi trajectory data to evaluate traffic flow at different granularities. Second, the centrality indices are calculated based on research units at different granularities. Third, correlation analysis between the centrality indices and corresponding urban traffic flow is performed. Experimental results indicate that urbaxperimental results indicate that urbaxperimental results indicate that urban traffic flow is relatively influenced by the road network structure. However, urban traffic flow also depends on the research unit size. Traditional centralities and traffic flow exhibit a low correlation at point granularity but exhibit a high correlation at line and area granularities. Furthermore, the conclusions of this study reflect the universality of the modifiable areal unit problem.

  20. Method for Traffic Flow Estimation using On-dashboard Camera Image

    Kohei Arai

    2014-02-01

    Full Text Available This paper presents the method to estimate the traffic flow on the urban roadway by using car’s on-dashboard camera image. The system described, shows something new which utilizes only road traffic photo images to get the information about urban roadway traffic flow automatically.

  1. Method for Traffic Flow Estimation using On-dashboard Camera Image

    Kohei Arai; Steven Ray Sentinuwo

    2014-01-01

    This paper presents the method to estimate the traffic flow on the urban roadway by using car’s on-dashboard camera image. The system described, shows something new which utilizes only road traffic photo images to get the information about urban roadway traffic flow automatically.

  2. Personalised adaptive task selection in air traffic control: Effects on training efficiency and transfer.

    Salden, Ron; Paas, Fred; Van Merriënboer, Jeroen

    2008-01-01

    Salden, R.J.C.M., Paas, F., & Van Merriënboer, J.J.G. (2006). Personalised adaptive task selection in air traffic control: Effects on training efficiency and transfer. Learning and Instruction, 16, 350-362

  3. Robust PCA-Based Abnormal Traffic Flow Pattern Isolation and Loop Detector Fault Detection

    JIN Xuexiang; ZHANG Yi; LI Li; HU Jianming

    2008-01-01

    One key function of intelligent transportation systems is to automatically detect abnormal traffic phenomena and to help further investigations of the cause of the abnormality. This paper describes a robust principal components analysis (RPCA)-based abnormal traffic flow pattern isolation and loop detector fault detection method. The results show that RPCA is a useful tool to distinguish regular traffic flow from abnor-mal traffic flow patterns caused by accidents and loop detector faults. This approach gives an effective traffic flow data pre-processing method to reduce the human effort in finding potential loop detector faults. The method can also be used to further investigate the causes of the abnormality.

  4. Self-sustained nonlinear waves in traffic flow.

    Flynn, M R; Kasimov, A R; Nave, J-C; Rosales, R R; Seibold, B

    2009-05-01

    In analogy to gas-dynamical detonation waves, which consist of a shock with an attached exothermic reaction zone, we consider herein nonlinear traveling wave solutions to the hyperbolic ("inviscid") continuum traffic equations. Generic existence criteria are examined in the context of the Lax entropy conditions. Our analysis naturally precludes traveling wave solutions for which the shocks travel downstream more rapidly than individual vehicles. Consistent with recent experimental observations from a periodic roadway [Y. Sugiyama, N. J. Phys. 10, 033001 (2008)], our numerical calculations show that nonlinear traveling waves are attracting solutions, with the time evolution of the system converging toward a wave-dominated configuration. Theoretical principles are elucidated by considering examples of traffic flow on open and closed roadways. PMID:19518527

  5. The Research of Traffic Flow Assignment Model based on the Network Calculus of Computer Network

    Jiayao Liu

    2012-01-01

    Full Text Available The existing dynamic traffic assignment researches mostly based on ideal hypothesis conditions which can analyze the affection of all kinds of traffic parameters on traffic flow and find out characteristics of various types of traffic distribution, but there is rarely have accurate calculation of flow distribution model. The study will first apply the network equilibrium theory into dynamic traffic flow assignment. Using Leaky Bucket Controller and Network Calculus, complicated traffic elements will incorporate into unified mathematical model called T-S Constrained Model, we can deduce flow assignment rate which is in a delay-limited constraints. The simulation results manifest that the model can not only solves congestion, but also reduce average delay of every path, it can extremely improve the traffic capacity of road network. The accurate assignment solutions will have significant impact on traffic engineering implementation.

  6. A Queuing Model-Based System for Triggering Traffic Flow Management Algorithms Project

    National Aeronautics and Space Administration — Next generation air traffic management systems are expected use multiple software tools and quantitative methods for managing traffic flow in the National Airspace....

  7. Implementation of Neural Network with a variant of Turing Machine for Traffic Flow Control

    Rashmi Sehrawat

    2013-05-01

    Full Text Available The conventional method of operation of a typical traffic light is to distribute the time equally for all the directions.This method causes congestion when throughput of the signal increases and is alsoineffective in managing traffic flow. In this paper, we have proposed a new model for managing traffic intelligently.The model is based on Turing machine with the application of neural network. The modelconsiders current traffic status of its own signal along with the status of its adjacent signals to determine the ratio of time slot for each signal therefore, reducing traffic congestion to a greater extent and ensuring steady flow of traffic in a wide region.

  8. Validity of Spontaneous Braking and Lane Changing with Scope of Awareness by Using Measured Traffic Flow

    Kohei Arai; Steven Ray Sentinuwo

    2013-01-01

    This paper presents the validation method and its evaluation of the spontaneous braking and lane changing with scope awareness parameter. By using the real traffic flow data, the traffic cellular automaton model that accommodate these two driver behaviors, e.g., spontaneous braking and driver scope awareness has been compared and evaluated. The real traffic flow data have been observed via video-recording captured from real traffic situation. The validation results shown that by accommodate s...

  9. Models, methods and software tools for building complex adaptive traffic systems

    The paper studies the modern methods and tools to simulate the behavior of complex adaptive systems (CAS), the existing systems of traffic modeling in simulators and their characteristics; proposes requirements for assessing the suitability of the system to simulate the CAS behavior in simulators. The author has developed a model of adaptive agent representation and its functioning environment to meet certain requirements set above, and has presented methods of agents' interactions and methods of conflict resolution in simulated traffic situations. A simulation system realizing computer modeling for simulating the behavior of CAS in traffic situations has been created

  10. Throughput Enhancement Using Adaptive Delay Barrier Function over HSDPA System in Mixed Traffic Scenarios

    Kim, Yong-Seok

    In this paper, we consider a method to enhance the throughput of HSDPA systems in the mixed traffic scenario. A channel-dependent adaptive delay barrier (DB) function is proposed to maximize throughput of best-effort (BE) traffic while satisfying the delay latency of voice over internet protocol (VoIP) service. Simulations show that the proposed channel-adaptive DB function raises the throughput of BE traffic service by 30% compared to the conventional scheme, without degrading the capacity of VoIP service over HSDPA system.

  11. Macroscopic Model and Simulation Analysis of Air Traffic Flow in Airport Terminal Area

    Honghai Zhang

    2014-01-01

    Full Text Available We focus on the spatiotemporal characteristics and their evolvement law of the air traffic flow in airport terminal area to provide scientific basis for optimizing flight control processes and alleviating severe air traffic conditions. Methods in this work combine mathematical derivation and simulation analysis. Based on cell transmission model the macroscopic models of arrival and departure air traffic flow in terminal area are established. Meanwhile, the interrelationship and influential factors of the three characteristic parameters as traffic flux, density, and velocity are presented. Then according to such models, the macro emergence of traffic flow evolution is emulated with the NetLogo simulation platform, and the correlativity of basic traffic flow parameters is deduced and verified by means of sensitivity analysis. The results suggest that there are remarkable relations among the three characteristic parameters of the air traffic flow in terminal area. Moreover, such relationships evolve distinctly with the flight procedures, control separations, and ATC strategies.

  12. Modeling, Identification, Estimation, and Simulation of Urban Traffic Flow in Jakarta and Bandung

    Herman Y. Sutarto

    2015-06-01

    Full Text Available This paper presents an overview of urban traffic flow from the perspective of system theory and stochastic control. The topics of modeling, identification, estimation and simulation techniques are evaluated and validated using actual traffic flow data from the city of Jakarta and Bandung, Indonesia, and synthetic data generated from traffic micro-simulator VISSIM. The results on particle filter (PF based state estimation and Expectation-Maximization (EM based parameter estimation (identification confirm the proposed model gives satisfactory results that capture the variation of urban traffic flow. The combination of the technique and the simulator platform assembles possibility to develop a real-time traffic light controller.  

  13. Monitoring individual traffic flows within the ATLAS TDAQ network

    Sjoen, R; Ciobotaru, M; Batraneanu, S M; Leahu, L; Martin, B; Al-Shabibi, A

    2010-01-01

    The ATLAS data acquisition system consists of four different networks interconnecting up to 2000 processors using up to 200 edge switches and five multi-blade chassis devices. The architecture of the system has been described in [1] and its operational model in [2]. Classical, SNMP-based, network monitoring provides statistics on aggregate traffic, but for performance monitoring and troubleshooting purposes there was an imperative need to identify and quantify single traffic flows. sFlow [3] is an industry standard based on statistical sampling which attempts to provide a solution to this. Due to the size of the ATLAS network, the collection and analysis of the sFlow data from all devices generates a data handling problem of its own. This paper describes how this problem is addressed by making it possible to collect and store data either centrally or distributed according to need. The methods used to present the results in a relevant fashion for system analysts are discussed and we explore the possibilities a...

  14. Monitoring individual traffic flows within the ATLAS TDAQ network

    Sjoen, R; Batraneanu, S M; Leahu, L; Martin, B; Al-Shabibi, A [CERN, 1211 Geneva 23 (Switzerland); Stancu, S; Ciobotaru, M, E-mail: rune.velle.sjoen@cern.c [' Politehnica' University of Bucharest (Romania)

    2010-04-01

    The ATLAS data acquisition system consists of four different networks interconnecting up to 2000 processors using up to 200 edge switches and five multi-blade chassis devices. The architecture of the system has been described in [1] and its operational model in [2]. Classical, SNMP-based, network monitoring provides statistics on aggregate traffic, but for performance monitoring and troubleshooting purposes there was an imperative need to identify and quantify single traffic flows. sFlow [3] is an industry standard based on statistical sampling which attempts to provide a solution to this. Due to the size of the ATLAS network, the collection and analysis of the sFlow data from all devices generates a data handling problem of its own. This paper describes how this problem is addressed by making it possible to collect and store data either centrally or distributed according to need. The methods used to present the results in a relevant fashion for system analysts are discussed and we explore the possibilities and limitations of this diagnostic tool, giving an example of its use in solving system problems that arise during the ATLAS data taking.

  15. Monitoring individual traffic flows within the ATLAS TDAQ network

    The ATLAS data acquisition system consists of four different networks interconnecting up to 2000 processors using up to 200 edge switches and five multi-blade chassis devices. The architecture of the system has been described in [1] and its operational model in [2]. Classical, SNMP-based, network monitoring provides statistics on aggregate traffic, but for performance monitoring and troubleshooting purposes there was an imperative need to identify and quantify single traffic flows. sFlow [3] is an industry standard based on statistical sampling which attempts to provide a solution to this. Due to the size of the ATLAS network, the collection and analysis of the sFlow data from all devices generates a data handling problem of its own. This paper describes how this problem is addressed by making it possible to collect and store data either centrally or distributed according to need. The methods used to present the results in a relevant fashion for system analysts are discussed and we explore the possibilities and limitations of this diagnostic tool, giving an example of its use in solving system problems that arise during the ATLAS data taking.

  16. Traffic Flow Management Using Aggregate Flow Models and the Development of Disaggregation Methods

    Sun, Dengfeng; Sridhar, Banavar; Grabbe, Shon

    2010-01-01

    A linear time-varying aggregate traffic flow model can be used to develop Traffic Flow Management (tfm) strategies based on optimization algorithms. However, there are no methods available in the literature to translate these aggregate solutions into actions involving individual aircraft. This paper describes and implements a computationally efficient disaggregation algorithm, which converts an aggregate (flow-based) solution to a flight-specific control action. Numerical results generated by the optimization method and the disaggregation algorithm are presented and illustrated by applying them to generate TFM schedules for a typical day in the U.S. National Airspace System. The results show that the disaggregation algorithm generates control actions for individual flights while keeping the air traffic behavior very close to the optimal solution.

  17. A stochastic approach to the flow-concentration curve in traffic flow theory

    Qian, Wei-Liang; Lin, Kai; Siqueira, Adriano F

    2016-01-01

    An alternative stochastic model for the fundamental diagram of traffic flow with minimal number of parameters is proposed. The key features of the model lie in its "catastrophic" potential function as well as in its stochastic nature, which makes it possible to describe the main features of the flow-concentration relation. In particular, the inverse-$\\lambda$ shape as well as the wide scattering of congested traffic data are both reproduced. In our model, the scattering of the data is attributed to the noise terms introduced in the stochastic differential equations. The inverse-$\\lambda$ shape and the associated sudden jump of physical quantities arise, on the other hand, due to the existence of two simultaneous stable traffic flow states and/or to the effect of stochastic noises on the stability of the system. The model parameters are calibrated and compared qualitatively with the data.

  18. A Modified Cellular Automaton Approach for Mixed Bicycle Traffic Flow Modeling

    Xiaonian Shan

    2015-01-01

    Full Text Available Several previous studies have used the Cellular Automaton (CA for the modeling of bicycle traffic flow. However, previous CA models have several limitations, resulting in differences between the simulated and the observed traffic flow features. The primary objective of this study is to propose a modified CA model for simulating the characteristics of mixed bicycle traffic flow. Field data were collected on physically separated bicycle path in Shanghai, China, and were used to calibrate the CA model using the genetic algorithm. Traffic flow features between simulations of several CA models and field observations were compared. The results showed that our modified CA model produced more accurate simulation for the fundamental diagram and the passing events in mixed bicycle traffic flow. Based on our model, the bicycle traffic flow features, including the fundamental diagram, the number of passing events, and the number of lane changes, were analyzed. We also analyzed the traffic flow features with different traffic densities, traffic components on different travel lanes. Results of the study can provide important information for understanding and simulating the operations of mixed bicycle traffic flow.

  19. Understanding urban traffic-flow characteristics: a rethinking of betweenness centrality

    Song Gao; Yaoli Wang; Yong Gao; Yu Liu

    2013-01-01

    In this study we estimate urban traffic flow using GPS-enabled taxi trajectory data in Qingdao, China, and examine the capability of the betweenness centrality of the street network to predict traffic flow. The results show that betweenness centrality is not a good predictor variable for urban traffic flow, which has, theoretically, been pointed out in existing literature. With a critique of the betweenness centrality as a predictor, we further analyze the characteristics of betweenness centr...

  20. A Modified Cellular Automaton Approach for Mixed Bicycle Traffic Flow Modeling

    Xiaonian Shan; Zhibin Li; Xiaohong Chen; Jianhong Ye

    2015-01-01

    Several previous studies have used the Cellular Automaton (CA) for the modeling of bicycle traffic flow. However, previous CA models have several limitations, resulting in differences between the simulated and the observed traffic flow features. The primary objective of this study is to propose a modified CA model for simulating the characteristics of mixed bicycle traffic flow. Field data were collected on physically separated bicycle path in Shanghai, China, and were used to calibrate the C...

  1. TO THE QUESTION OF SOLVING OF THE PROBLEM OF OPTIMIZING PARAMETERS OF TRAFFIC FLOW COORDINATED CONTROL

    L. Abramova; Chernobaev, N.

    2007-01-01

    A short review of main methods of traffic flow control is represented, great attention is paid to methods of coordinated control and quality characteristics of traffic control. The problem of parameter optimization of traffic coordinated control on the basis of vehicle delay minimizing at highway intersections has been defined.

  2. Real-time Capturing and Measurement of Traffic Flow Based on WinPcap

    HU Wen-jing; LI Ming; QIU Run-he; LIU Jin-gao

    2006-01-01

    In order to understand how a network is being used or whether it is being abused, an administrator needs to inspect the flow of the traffic and "infers" the intent of the users and applications. So the network traffic measurement and analysis are crucial to network monitoring, reliable DDoS detecting and attack source locating as well[1-4]. In this paper, we discuss the principle of real-time network traffic measurement and analysis through embedding a traffic measurement and analysis engine into IP packet-decoding module, and emphasize the implementation of visualizing the real-time network traffic, which are helpful to network monitoring and network traffic modeling.

  3. An Adaptive Service Platform for Traffic Management and Surveillance

    Sapkota, Brahmananda; Sinderen, van Marten

    2011-01-01

    The increasing number of road vehicles has given rise to increasingly adverse consequences in the society. Some of the major concerns that arise due to such an increase in road vehicles are: safety of the people using the road, cost and efficiency of the traffic management and the environmental foot

  4. Stabilization of traffic flow in optimal velocity model via delayed-feedback control

    Jin, Yanfei; Hu, Haiyan

    2013-04-01

    Traffic jams may occur due to various reasons, such as traffic accidents, lane reductions and on-ramps. In order to suppress the traffic congestion in an optimal velocity traffic model without any driver's delay taken into account, a delayed-feedback control of both displacement and velocity differences is proposed in this study. By using the delay-independent stability criteria and the H∞-norm, the delayed-feedback control can be determined to stabilize the unstable traffic flow and suppress the traffic jam. The numerical case studies are given to demonstrate and verify the new control method. Furthermore, a comparison is made between the new control method and the method proposed by Konishi et al. [K. Konishi, M. Hirai, H. Kokame, Decentralized delayed-feedback control of an optimal velocity traffic model, Eur. Phys. J. B 15 (2000) 715-722]. The results show that the new control method makes the traffic flow more stable and improves the control performance.

  5. Failure of classical traffic flow theories: Stochastic highway capacity and automatic driving

    Kerner, Boris S.

    2016-05-01

    In a mini-review Kerner (2013) it has been shown that classical traffic flow theories and models failed to explain empirical traffic breakdown - a phase transition from metastable free flow to synchronized flow at highway bottlenecks. The main objective of this mini-review is to study the consequence of this failure of classical traffic-flow theories for an analysis of empirical stochastic highway capacity as well as for the effect of automatic driving vehicles and cooperative driving on traffic flow. To reach this goal, we show a deep connection between the understanding of empirical stochastic highway capacity and a reliable analysis of automatic driving vehicles in traffic flow. With the use of simulations in the framework of three-phase traffic theory, a probabilistic analysis of the effect of automatic driving vehicles on a mixture traffic flow consisting of a random distribution of automatic driving and manual driving vehicles has been made. We have found that the parameters of automatic driving vehicles can either decrease or increase the probability of the breakdown. The increase in the probability of traffic breakdown, i.e., the deterioration of the performance of the traffic system can occur already at a small percentage (about 5%) of automatic driving vehicles. The increase in the probability of traffic breakdown through automatic driving vehicles can be realized, even if any platoon of automatic driving vehicles satisfies condition for string stability.

  6. Dynamic route guidance strategy in a two-route pedestrian-vehicle mixed traffic flow system

    Liu, Mianfang; Xiong, Shengwu; Li, Bixiang

    2016-05-01

    With the rapid development of transportation, traffic questions have become the major issue for social, economic and environmental aspects. Especially, during serious emergencies, it is very important to alleviate road traffic congestion and improve the efficiency of evacuation to reduce casualties, and addressing these problems has been a major task for the agencies responsible in recent decades. Advanced road guidance strategies have been developed for homogeneous traffic flows, or to reduce traffic congestion and enhance the road capacity in a symmetric two-route scenario. However, feedback strategies have rarely been considered for pedestrian-vehicle mixed traffic flows with variable velocities and sizes in an asymmetric multi-route traffic system, which is a common phenomenon in many developing countries. In this study, we propose a weighted road occupancy feedback strategy (WROFS) for pedestrian-vehicle mixed traffic flows, which considers the system equilibrium to ease traffic congestion. In order to more realistic simulating the behavior of mixed traffic objects, the paper adopted a refined and dynamic cellular automaton model (RDPV_CA model) as the update mechanism for pedestrian-vehicle mixed traffic flow. Moreover, a bounded rational threshold control was introduced into the feedback strategy to avoid some negative effect of delayed information and reduce. Based on comparisons with the two previously proposed strategies, the simulation results obtained in a pedestrian-vehicle traffic flow scenario demonstrated that the proposed strategy with a bounded rational threshold was more effective and system equilibrium, system stability were reached.

  7. Traffic Flow Analysis Model based Routing Protocol For Multi-Protocol Label Switching Network

    E.R. Naganathan; Rajagopalan, S.; P. H. Raj

    2011-01-01

    Problem statement: Multi-Protocol Label Switching (MPLS) is a mechanism which is used in high-performance telecommunications networks that directs and carries data from one network node to the next with the help of labels. Traffic management is still an issue in MPLS network as it involves high speed internet. Approach: This study proposed a traffic flow analysis of the real time MPLS traffic and segregates the MPLS traffic as three major class based on the outcome of traffic flow analysis. U...

  8. Relationship between crash rate and hourly traffic flow on interurban motorways

    Martin, JL

    2002-01-01

    This paper describes the relationship between crash incidence rates and hourly traffic volume and discusses the influence of traffic on crash severity, based on observations made on 2000 km of french interurban motorways over 2 years. Incidence rates involving property damage-only crashes and injury-crashes are highest when traffic is lightest (under 400 vehicles/h). These incidence rates are at their lowest when traffic flows at a rate of 1000-1500 vehicles/h. For heavier traffic flows, cras...

  9. Portable Telematic System as an Effective Traffic Flow Management in Workzones

    Ščerba Marek; Apeltauer Tomáš; Apeltauer Jiří

    2015-01-01

    Traffic infrastructure localities with temporal restrictions for example due to reconstructions, or modernization, are important aspects influencing the traffic safety and traffic flow. On the basis of our research, we can identify main factors, which generate travel time loses, and which often cause traffic accidents in bottlenecks. First of all, it is improper late merge, speeding, tailgating, lower tolerance and consideration to other road users. Nervousness and ignorance of drivers also p...

  10. Implementation of Neural Network with a variant of Turing Machine for Traffic Flow Control

    Rashmi Sehrawat; Honey Malviya; Vanditaa Kaul

    2013-01-01

    The conventional method of operation of a typical traffic light is to distribute the time equally for all the directions.This method causes congestion when throughput of the signal increases and is alsoineffective in managing traffic flow. In this paper, we have proposed a new model for managing traffic intelligently.The model is based on Turing machine with the application of neural network. The modelconsiders current traffic status of its own signal along with the status of its adjacent sig...

  11. Perturbation analysis and sample-path optimization: stochastic flow models of urban traffic networks case

    Sutarto, Herman; Boel, René

    2009-01-01

    Coordination of traffic streams in an urban network, controllable by switching traffic lights, requires a global macroscopic model of the evolution of the flows of vehicle. We propose the use fluid petri nets as modeling tools. For the design of on-line controllers for traffic lights we study the network-wide effects of different local perturbations of the traffic light switching times via fast simulation. The infinitesimal perturbation analysis can under certain conditions lead to optimal cl...

  12. Understanding widely scattered traffic flows, the capacity drop, and platoons as effects of variance-driven time gaps

    Treiber, Martin; Kesting, Arne; Helbing, Dirk

    2006-07-01

    We investigate the adaptation of the time headways in car-following models as a function of the local velocity variance, which is a measure of the inhomogeneity of traffic flow. We apply this mechanism to several car-following models and simulate traffic breakdowns in open systems with an on-ramp as bottleneck and in a closed ring road. Single-vehicle data and one-minute aggregated data generated by several virtual detectors show a semiquantitative agreement with microscopic and flow-density data from the Dutch freeway A9. This includes the observed distributions of the net time headways for free and congested traffic, the velocity variance as a function of density, and the fundamental diagram. The modal value of the time headway distribution is shifted by a factor of about 2 under congested conditions. Macroscopically, this corresponds to the capacity drop at the transition from free to congested traffic. The simulated fundamental diagram shows free, synchronized, and jammed traffic, and a wide scattering in the congested traffic regime. We explain this by a self-organized variance-driven process that leads to the spontaneous formation and decay of long-lived platoons even for a deterministic dynamics on a single lane.

  13. Acceleration of aircraft-level Traffic Flow Management

    Rios, Joseph Lucio

    This dissertation describes novel approaches to solving large-scale, high fidelity, aircraft-level Traffic Flow Management scheduling problems. Depending on the methods employed, solving these problems to optimality can take longer than the length of the planning horizon in question. Research in this domain typically focuses on the quality of the modeling used to describe the problem and the benefits achieved from the optimized solution, often treating computational aspects as secondary or tertiary. The work presented here takes the complementary view and considers the computational aspect as the primary concern. To this end, a previously published model for solving this Traffic Flow Management scheduling problem is used as starting point for this study. The model proposed by Bertsimas and Stock-Patterson is a binary integer program taking into account all major resource capacities and the trajectories of each flight to decide which flights should be held in which resource for what amount of time in order to satisfy all capacity requirements. For large instances, the solve time using state-of-the-art solvers is prohibitive for use within a potential decision support tool. With this dissertation, however, it will be shown that solving can be achieved in reasonable time for instances of real-world size. Five other techniques developed and tested for this dissertation will be described in detail. These are heuristic methods that provide good results. Performance is measured in terms of runtime and "optimality gap." We then describe the most successful method presented in this dissertation: Dantzig-Wolfe Decomposition. Results indicate that a parallel implementation of Dantzig-Wolfe Decomposition optimally solves the original problem in much reduced time and with better integrality and smaller optimality gap than any of the heuristic methods or state-of-the-art, commercial solvers. The solution quality improves in every measureable way as the number of subproblems

  14. Formation of density waves in traffic flow through intersecting roads.

    Ray, B; Bhattacharyya, S N

    2006-03-01

    The formation of density waves in two intersecting roads, with a traffic circle at the intersection, is studied. It is found that, depending on the traffic densities in the two roads, density waves can form in the traffic circle and in one or both of the roads. Depending on the expression chosen for the optimal velocity, either the congestion moves entirely to the traffic circle or the congestion becomes confined to the traffic circle and a part of the road approaching the traffic circle. PMID:16605592

  15. A cellular automata traffic flow model considering the heterogeneity of acceleration and delay probability

    Li, Qi-Lang; Wong, S. C.; Min, Jie; Tian, Shuo; Wang, Bing-Hong

    2016-08-01

    This study examines the cellular automata traffic flow model, which considers the heterogeneity of vehicle acceleration and the delay probability of vehicles. Computer simulations are used to identify three typical phases in the model: free-flow, synchronized flow, and wide moving traffic jam. In the synchronized flow region of the fundamental diagram, the low and high velocity vehicles compete with each other and play an important role in the evolution of the system. The analysis shows that there are two types of bistable phases. However, in the original Nagel and Schreckenberg cellular automata traffic model, there are only two kinds of traffic conditions, namely, free-flow and traffic jams. The synchronized flow phase and bistable phase have not been found.

  16. Incorporating User Preferences Within an Optimal Traffic Flow Management Framework

    Rios, Joseph Lucio; Sheth, Kapil S.; Guiterrez-Nolasco, Sebastian Armardo

    2010-01-01

    The effectiveness of future decision support tools for Traffic Flow Management in the National Airspace System will depend on two major factors: computational burden and collaboration. Previous research has focused separately on these two aspects without consideration of their interaction. In this paper, their explicit combination is examined. It is shown that when user preferences are incorporated with an optimal approach to scheduling, runtime is not adversely affected. A benefit-cost ratio is used to measure the influence of user preferences on an optimal solution. This metric shows user preferences can be accommodated without inordinately, negatively affecting the overall system delay. Specifically, incorporating user preferences will increase delays proportionally to increased user satisfaction.

  17. Microsimulation study of vehicular interactions in heterogeneous traffic flow on intercity roads

    Arasan, V. Thamizh; Arkatkar, Shriniwas S.

    2011-01-01

    Study of the basic traffic flow characteristics and comprehensive understanding of vehicular interaction are the pre-requisites for highway capacity and level of service analyses and formulation of effective traffic regulation and control measures. This is better done by modeling the system, which will enable the study of the influencing factors over a wide range. Computer simulation has emerged as an effective technique for modeling traffic flow due to its capability to account f...

  18. Macroscopic Model and Simulation Analysis of Air Traffic Flow in Airport Terminal Area

    Honghai Zhang; Yan Xu; Lei Yang; Hao Liu

    2014-01-01

    We focus on the spatiotemporal characteristics and their evolvement law of the air traffic flow in airport terminal area to provide scientific basis for optimizing flight control processes and alleviating severe air traffic conditions. Methods in this work combine mathematical derivation and simulation analysis. Based on cell transmission model the macroscopic models of arrival and departure air traffic flow in terminal area are established. Meanwhile, the interrelationship and influential fa...

  19. Analysis of CO2 emission in traffic flow and numerical tests

    Zhu, Wen-Xing

    2013-10-01

    We investigated the carbon dioxide emission rate in traffic flow analytically and numerically. The emission model was derived based on Bando’s optimal velocity model with a consideration of slope. Simulations were conducted to examine the relationship between the CO2 emission rate of vehicles and slope of road, traffic density, and road length. Analysis of the results shows that some original laws of CO2 emission in traffic flow with congestion were exhibited.

  20. Heterogenous motorised traffic flow modelling using cellular automata

    Deo, Puspita

    2007-01-01

    Traffic congestion is a major problem in most major cities around the world with few signs that this is diminishing, despite management efforts. In planning traffic management and control strategies at urban and inter urban level, understanding the factors involved in vehicular progression is vital. Most work to date has, however, been restricted to single vehicle-type traffic. Study of heterogeneous traffic movements for urban single and multi-lane roads has been limited, even for developed ...

  1. Multi-class continuum traffic flow models: Analysis and simulation methods

    Van Wageningen-Kessels, F.L.M.

    2013-01-01

    How to model and simulate traffic flow including different vehicles such as cars and trucks? This dissertation answers this question by analyzing existing models and simulation methods and by developing new ones. The new model (Fastlane) describes traffic as a continuum flow while accounting for dif

  2. An Improved Car-Following Model for Multiphase Vehicular Traffic Flow and Numerical Tests

    This paper attempts to introduce an improved difference model that modifies a car-following model, which takes the next-nearest-neighbor interaction into account. The improvement of this model over the previous one lies in that it performs more realistically in the dynamical motion for small delay time. The traffic behavior of the improved model is investigated with analytic and numerical methods with the finding that the new consideration could further stabilize traffic flow. And some simulation tests verify that the proposed model can demonstrate some complex physical features observed recently in real traffic such as the existence of three phases: free flow, coexisting flow, and jam flow; spontaneous formation of density waves; sudden flow drop in flow-density plane; traffic hysteresis in transition between the free and the coexisting flow. Furthermore, the improved model also predicts that the stable state to relative density in the coexisting flow is insusceptible to noise.

  3. Video-based measurement and data analysis of traffic flow on urban expressways

    Xian-Qing Zheng; Zheng Wu; Shi-Xiong Xu; Ming-Min Guo; Zhan-Xi Lin; Ying-Ying Zhang

    2011-01-01

    A new video-based measurement is proposed to collect and investigate traffic flow parameters.The output of the measurement is velocity-headway distance data pairs.Because density can be directly acquired by the reciprocal of headway distance, the data pairs have the advantage of better simultaneity than those from common detectors.By now,over 33 000 pairs of data have been collected from two road sections in the cities of Shanghai and Zhengzhou.Through analyzing the video files recording traffic movements on urban expressways, the following issues are studied: laws of vehicle velocity changing with headway distance, proportions of different driving behaviors in the traffic system, and characteristics of traffic flow in snowy days.The results show that the real road traffic is very complex, and factors such as location and climate need to be taken into consideration in the formation of traffic flow models.

  4. Maximum flow in road networks with speed-dependent capacities – application to Bangkok traffic

    Elvin J Moore

    2013-08-01

    Full Text Available A road network can be modeled as a graph with a set of nodes representing intersections and a set of weighted edgesrepresenting road segments between intersections. In this paper, a traffic flow problem is studied, where edge weightsrepresent road capacities (maximum vehicles per hour that are functions of the traffic speed (km/hr and traffic density(vehicles per kilometer. To estimate road capacities for a given speed, empirical data on safe vehicle separations for a givenspeed are used. A modified version of the Ford-Fulkerson algorithm is developed to solve maximum flow problems with speeddependent capacities, with both one-way and two-way flows allowed on edges and with multiple source and target nodes.The modified algorithm is used to estimate maximum traffic flow through a selected network of roads in Bangkok. It was foundthat the maximum safe traffic flow occurs at a speed of 30 km/hr.

  5. The Study of Reinforcement Learning for Traffic Self-Adaptive Control under Multiagent Markov Game Environment

    Lun-Hui Xu

    2013-01-01

    Full Text Available Urban traffic self-adaptive control problem is dynamic and uncertain, so the states of traffic environment are hard to be observed. Efficient agent which controls a single intersection can be discovered automatically via multiagent reinforcement learning. However, in the majority of the previous works on this approach, each agent needed perfect observed information when interacting with the environment and learned individually with less efficient coordination. This study casts traffic self-adaptive control as a multiagent Markov game problem. The design employs traffic signal control agent (TSCA for each signalized intersection that coordinates with neighboring TSCAs. A mathematical model for TSCAs’ interaction is built based on nonzero-sum markov game which has been applied to let TSCAs learn how to cooperate. A multiagent Markov game reinforcement learning approach is constructed on the basis of single-agent Q-learning. This method lets each TSCA learn to update its Q-values under the joint actions and imperfect information. The convergence of the proposed algorithm is analyzed theoretically. The simulation results show that the proposed method is convergent and effective in realistic traffic self-adaptive control setting.

  6. Analysis of ETMS Data Quality for Traffic Flow Management Decisions

    Chatterji, Gano B.; Sridhar, Banavar; Kim, Douglas

    2003-01-01

    The data needed for air traffic flow management decision support tools is provided by the Enhanced Traffic Management System (ETMS). This includes both the tools that are in current use and the ones being developed for future deployment. Since the quality of decision support provided by all these tools will be influenced by the quality of the input ETMS data, an assessment of ETMS data quality is needed. Motivated by this desire, ETMS data quality is examined in this paper in terms of the unavailability of flight plans, deviation from the filed flight plans, departure delays, altitude errors and track data drops. Although many of these data quality issues are not new, little is known about their extent. A goal of this paper is to document the magnitude of data quality issues supported by numerical analysis of ETMS data. Guided by this goal, ETMS data for a 24-hour period were processed to determine the number of aircraft with missing flight plan messages at any given instant of time. Results are presented for aircraft above 18,000 feet altitude and also at all altitudes. Since deviation from filed flight plan is also a major cause of trajectory-modeling errors, statistics of deviations are presented. Errors in proposed departure times and ETMS-generated vertical profiles are also shown. A method for conditioning the vertical profiles for improving demand prediction accuracy is described. Graphs of actual sector counts obtained using these vertical profiles are compared with those obtained using the Host data for sectors in the Fort Worth Center to demonstrate the benefit of preprocessing. Finally, results are presented to quantify the extent of data drops. A method for propagating track positions during ETMS data drops is also described.

  7. Dynamics of Motorized Vehicle Flow under Mixed Traffic Circumstance*

    GUO nong-Wei; GAO Zi-You; ZHAO Xiao-Mei; XIE Dong-Fan

    2011-01-01

    To study the dynamics of mixed traffic flow consisting of motorized and non-motorized vehicles, a carfollowing model based on the principle of collision free and cautious driving is proposed.Lateral friction and overlapping driving are introduced to describe the interactions between motorized vehicles and non-motorized vehicles.By numerical simulations, the flux-density relation, the temporal-spatial dynamics, and the velocity evolution are investigated in detail.The results indicate non-motorized vehicles have a significant impact on the motorized vehicle flow and cause the maximum flux to decline by about 13%.Non-motorized vehicles can decrease the motorized vehicle velocity and cause velocity oscillation when the motorized vehicle density is low.Moreover, non-motorized vehicles show a significant damping effect on the oscillating velocity when the density is medium and high, and such an effect weakens as motorized vehicle densityincreases.The results also stress the necessity for separating motorized vehicles from non-motorized vehicles.

  8. Dynamics of Motorized Vehicle Flow under Mixed Traffic Circumstance

    To study the dynamics of mixed traffic flow consisting of motorized and non-motorized vehicles, a car-following model based on the principle of collision free and cautious driving is proposed. Lateral friction and overlapping driving are introduced to describe the interactions between motorized vehicles and non-motorized vehicles. By numerical simulations, the flux-density relation, the temporal-spatial dynamics, and the velocity evolution are investigated in detail. The results indicate non-motorized vehicles have a significant impact on the motorized vehicle flow and cause the maximum flux to decline by about 13%. Non-motorized vehicles can decrease the motorized vehicle velocity and cause velocity oscillation when the motorized vehicle density is low. Moreover, non-motorized vehicles show a significant damping effect on the oscillating velocity when the density is medium and high, and such an effect weakens as motorized vehicle density increases. The results also stress the necessity for separating motorized vehicles from non-motorized vehicles. (interdisciplinary physics and related areas of science and technology)

  9. CONCEPTION OF NEW ROAD-NODE JEŽICA IN LJUBLJANA DESIGNED CONSIDERING TRAFFIC-FLOWS

    Kralj, Gregor

    2011-01-01

    In this graduation thesis it will be shown how to design a new road-node Ježica in Ljubljana considering traffic-flows in this area. In the initial theoretical part the process of traffic planning will be presented, through a theory of four-stage models, which are the basis for traffic models, from which we get the corresponding traffic-flows. So-called interactive projecting it will also be introduced and explained. Then follows practical part, in which the analysis of existing transmitta...

  10. Detecting Anomaly in Traffic Flow from Road Similarity Analysis

    Liu, Xinran

    2016-06-02

    Taxies equipped with GPS devices are considered as 24-hour moving sensors widely distributed in urban road networks. Plenty of accurate and realtime trajectories of taxi are recorded by GPS devices and are commonly studied for understanding traffic dynamics. This paper focuses on anomaly detection in traffic volume, especially the non-recurrent traffic anomaly caused by unexpected or transient incidents, such as traffic accidents, celebrations and disasters. It is important to detect such sharp changes of traffic status for sensing abnormal events and planning their impact on the smooth volume of traffic. Unlike existing anomaly detection approaches that mainly monitor the derivation of current traffic status from history in the past, the proposed method in this paper evaluates the abnormal score of traffic on one road by comparing its current traffic volume with not only its historical data but also its neighbors. We define the neighbors as the roads that are close in sense of both geo-location and traffic patterns, which are extracted by matrix factorization. The evaluation results on trajectories data of 12,286 taxies over four weeks in Beijing show that our approach outperforms other baseline methods with higher precision and recall.

  11. CONTROLLING TRAFFIC FLOW IN MULTILANE-ISOLATED INTERSECTION USING ANFIS APPROACH TECHNIQUES

    G. R. LAI

    2015-08-01

    Full Text Available Many controllers have applied the Adaptive Neural-Fuzzy Inference System (ANFIS concept for optimizing the controller performance. However, there are less traffic signal controllers developed using the ANFIS concept. ANFIS traffic signal controller with its fuzzy rule base and its ability to learn from a set of sample data could improve the performance of Existing traffic signal controlling system to reduce traffic congestions at most of the busy traffic intersections in city such as Kuala Lumpur, Malaysia. The aim of this research is to develop an ANFIS traffic signals controller for multilane-isolated four approaches intersections in order to ease traffic congestions at traffic intersections. The new concept to generate sample data for ANFIS training is introduced in this research. The sample data is generated based on fuzzy rules and can be analysed using tree diagram. This controller is simulated on multilane-isolated traffic intersection model developed using M/M/1 queuing theory and its performance in terms of average waiting time, queue length and delay time are compared with traditional controllers and fuzzy controller. Simulation result shows that the average waiting time, queue length, and delay time of ANFIS traffic signal controller are the lowest as compared to the other three controllers. In conclusion, the efficiency and performance of ANFIS controller are much better than that of fuzzy and traditional controllers in different traffic volumes.

  12. Research on the Prediction of VNN Neural Network Traffic Flow Model Based on Chaotic Algorithm

    Yin Lisheng

    2013-06-01

    Full Text Available This paperresearches on the prediction of traffic flow chaotic time series based on VNNTF neural network. First, the traffic flow time series chaotic feature is extracted by chaos theory. Pretreatment for traffic flow time series and the VNNTP neural networks model was build by this. Second, principles of neural network learning algorithm VNNTF is described. Based on chaotic learning algorithm, the neural network traffic Volterra learning algorithm isdesigned for fast learning algorithm. Last, a single-step prediction of traffic flow chaotic time series is researched by VNNTF network model based on chaotic algorithm. The results showed that the VNNTF network model predictive performance is better than the Volterra prediction filter and the BP neural network   by the simulation results and root-mean-square value.

  13. Intelligent Controlling Simulation of Traffic Flow in a Small City Network

    Fouladvand, M E; Sadjadi, Z; Sadjadi, Zeinab

    2005-01-01

    We propose a two dimensional probabilistic cellular automata for the description of traffic flow in a small city network composed of two intersections. The traffic in the network is controlled by a set of traffic lights which can be operated both in fixed-time and a traffic responsive manner. Vehicular dynamics is simulated and the total delay experienced by the traffic is evaluated within specified time intervals. We investigate both decentralized and centralized traffic responsive schemes and in particular discuss the implementation of the {\\it green-wave} strategy. Our investigations prove that the network delay strongly depends on the signalisation strategy. We show that in some traffic conditions, the application of the green-wave scheme may destructively lead to the increment of the global delay.

  14. PRINCIPLES OF IMPROVEMENT OF AIR TRAFFIC FLOW AND CAPACITY MANAGEMENT IN TERMINAL CONTROL AREAS UNDER UNCERTAINTY CONDITIONS

    Kharchenko, Volodymyr; National Aviation University, Kyiv, Ukraine; Ningbo University of Technology, Ningbo, Zhejiang, China; Chynchenko, Yuriy; National Aviation University, Kyiv

    2013-01-01

    The article deals with the analysis of the researches conducted in the field of the air traffic flow and capacity management in terminal control areas under uncertainty conditions. Traffic flows indicators, uncertainty factors and air traffic flow management in terminal control areas have been reviewed. Principles of improvement of air traffic flow and capacity management in terminal control areas have been analysed and conclusions regarding Ukrainian aeronautical system have been proposed

  15. Traffic Flow at Sags: Theory, Modeling and Control

    Goni-Ros, B.

    2016-01-01

    Sag vertical curves (sags) are roadway sections along which the gradient increases gradually in the direction of traffic. Empirical observations show that, on freeways, traffic congestion often occurs at sags; actually, in some countries (e.g., Japan), sags are one of the most common types of freeway bottleneck. This thesis is the outcome of a research project funded by Toyota whose objective was to develop new concepts for traffic management at freeway sags based on a thorough understanding ...

  16. Self-Adapting Routing Overlay Network for Frequently Changing Application Traffic in Content-Based Publish/Subscribe System

    Meng Chi

    2014-01-01

    Full Text Available In the large-scale distributed simulation area, the topology of the overlay network cannot always rapidly adapt to frequently changing application traffic to reduce the overall traffic cost. In this paper, we propose a self-adapting routing strategy for frequently changing application traffic in content-based publish/subscribe system. The strategy firstly trains the traffic information and then uses this training information to predict the application traffic in the future. Finally, the strategy reconfigures the topology of the overlay network based on this predicting information to reduce the overall traffic cost. A predicting path is also introduced in this paper to reduce the reconfiguration numbers in the process of the reconfigurations. Compared to other strategies, the experimental results show that the strategy proposed in this paper could reduce the overall traffic cost of the publish/subscribe system in less reconfigurations.

  17. Traffic-Flow Analysis for Fast Performance Estimation of Communication Systems

    Lencse, Gábor

    2001-01-01

    The traffic-flow analysis (TFA) is a promising method for the performance estimation of communication systems. TFA produces approximate results with much less computation (that is, much faster) than discrete-event simulation of the system. In the first step, TFA distributes the traffic in units of properly chosen size using the actual routing algorithm of the network. In the second step, TFA adjusts the time distribution of the traffic according to the finite capacities of the network. It was...

  18. Maximum flow in road networks with speed-dependent capacities – application to Bangkok traffic

    Elvin J Moore; Wisut Kichainukon; Utomporn Phalavonk

    2013-01-01

    A road network can be modeled as a graph with a set of nodes representing intersections and a set of weighted edgesrepresenting road segments between intersections. In this paper, a traffic flow problem is studied, where edge weightsrepresent road capacities (maximum vehicles per hour) that are functions of the traffic speed (km/hr) and traffic density(vehicles per kilometer). To estimate road capacities for a given speed, empirical data on safe vehicle separations for a givenspeed are used. ...

  19. A strongly coupled PDE-ODE system modeling moving density constraints in traffic flow

    Delle Monache, Maria Laura; Goatin, Paola

    2012-01-01

    International audience We prove the existence of solutions of a coupled PDE-ODE system modeling the interaction of a large slow moving vehicle with the surrounding traffic flow. The model consists in a scalar conservation law with moving density constraint describing traffic evolution coupled with an ODE for the slow vehicle trajectory. The constraint location moves due to the surrounding traffic conditions, which in turn are affected by the presence of the slower vehicle, thus resulting i...

  20. Failure of classical traffic flow theories: Stochastic highway capacity and automatic driving

    Kerner, Boris S

    2016-01-01

    In a mini-review [Physica A {\\bf 392} (2013) 5261--5282] it has been shown that classical traffic flow theories and models failed to explain empirical traffic breakdown -- a phase transition from metastable free flow to synchronized flow at highway bottlenecks. The main objective of this mini-review is to study the consequence of this failure of classical traffic-flow theories for an analysis of empirical stochastic highway capacity as well as for the effect of automatic driving vehicles and cooperative driving on traffic flow. To reach this goal, we show a deep connection between the understanding of empirical stochastic highway capacity and a reliable analysis of automatic driving vehicles in traffic flow. With the use of simulations in the framework of three-phase traffic theory, a probabilistic analysis of the effect of automatic driving vehicles on a mixture traffic flow consisting of a random distribution of automatic driving and manual driving vehicles has been made. We have found that the parameters o...

  1. Traffic management as a service: the traffic flow pattern classification problem

    Carlos T. Calafate; David Soler; Juan-Carlos Cano; Pietro Manzoni

    2015-01-01

    Intelligent Transportation System (ITS) technologies can be implemented to reduce both fuel consumption and the associated emission of greenhouse gases. However, such systems require intelligent and effective route planning solutions to reduce travel time and promote stable traveling speeds. To achieve such goal these systems should account for both estimated and real-time traffic congestion states, but obtaining reliable traffic congestion estimations for all the streets/avenues in a city...

  2. MEASURES TO IMPROVE THE TRAFFIC MANAGEMENT

    Дульгер, В.; Пиндюрина, Е.; Муратова, А.

    2012-01-01

    Everybody knows the volume of traffic on today's roads is increasing, thereby, reducing the capacity of the road which causes delays and congestion. "Traffic Management" is the termed as "ways and measures of adjusting, accommodating or adapting the use of road space available without building new ones". The key objective of introducing traffic management measures is to achieve one of the following: improve the flow of traffic, or specific types of traffic (e.g. bus / cycle priority measures)...

  3. A SPATIOTEMPORAL APPROACH FOR HIGH RESOLUTION TRAFFIC FLOW IMPUTATION

    Han, Lee [University of Tennessee, Knoxville (UTK); Chin, Shih-Miao [ORNL; Hwang, Ho-Ling [ORNL

    2016-01-01

    Along with the rapid development of Intelligent Transportation Systems (ITS), traffic data collection technologies have been evolving dramatically. The emergence of innovative data collection technologies such as Remote Traffic Microwave Sensor (RTMS), Bluetooth sensor, GPS-based Floating Car method, automated license plate recognition (ALPR) (1), etc., creates an explosion of traffic data, which brings transportation engineering into the new era of Big Data. However, despite the advance of technologies, the missing data issue is still inevitable and has posed great challenges for research such as traffic forecasting, real-time incident detection and management, dynamic route guidance, and massive evacuation optimization, because the degree of success of these endeavors depends on the timely availability of relatively complete and reasonably accurate traffic data. A thorough literature review suggests most current imputation models, if not all, focus largely on the temporal nature of the traffic data and fail to consider the fact that traffic stream characteristics at a certain location are closely related to those at neighboring locations and utilize these correlations for data imputation. To this end, this paper presents a Kriging based spatiotemporal data imputation approach that is able to fully utilize the spatiotemporal information underlying in traffic data. Imputation performance of the proposed approach was tested using simulated scenarios and achieved stable imputation accuracy. Moreover, the proposed Kriging imputation model is more flexible compared to current models.

  4. Effect of the Primary User Traffic on Cognitive Relaying with Adaptive Transmission

    Rao, Anlei

    2012-09-08

    In a cognitive-relay system, the secondary user is permitted to transmit data via a relay when the spectrum bands are detected to be free. The miss detection of spectrum sensing and the primary user traffic will affect the data transmission performance of the secondary user. In this paper, we investigate the impact of the status change of the primary user on the bit error rate (BER) of the adaptive transmission of the secondary user in a cognitive-relay system. Numerical results show that the primary user traffic can significantly degrade the BER of the secondary user transmission.

  5. Dynamic aggregation of traffic flows in SDN Applied to backhaul networks

    Kentis, Angelos Mimidis; Caba, Cosmin Marius; Soler, José

    2016-01-01

    or they can support a very limited number of OF rules. One way to cope with this limitation, is to perform the same logic but with fewer OF rules in the devices. As a demonstration of this operational strategy, the current paper proposes a service for traffic flow aggregation which reduces the number...... of OF rules needed in the network devices, without impacting the control plane logic. The proposed traffic flow aggregation service is tested on a set of topologies specific to the backhaul network, since they aggregate a large amount of traffic flows. The results illustrate significant reductions...

  6. Slow-to-start effect in two-dimensional traffic flow

    Sui, Qiao-Hong; Ding, Zhong-Jun; Jiang, Rui; Huang, Wei; Sun, Duo; Wang, Bing-Hong

    2012-03-01

    This paper studies slow-to-start effect in two-dimensional Biham-Middleton-Levine (BML) traffic flow model with traffic light periods T=2τ. In most cases, the model exhibits free flow, jam, and phase separation phenomenon. Nevertheless, when the slow-to-start parameter p=0, and traffic light parameter τ=3 or 5, it is found that phase separation phenomenon does not occur. We have explained this via the evolution process from a designed regular initial configuration. Moreover, it is also found that the free flow self-organizes into grid-like structure when τ is large and the slow-to-start parameter 0

  7. Empirical Features of Spontaneous and Induced Traffic Breakdowns in Free Flow at Highway Bottlenecks

    Kerner, Boris S; Klenov, Sergey L; Rehborn, Hubert; Leibel, Michael

    2015-01-01

    Based on an empirical study of real field traffic data measured in 1996--2014 through road detectors installed on German freeways, we reveal physical features of empirical nuclei for spontaneous traffic breakdown in free flow at highway bottlenecks. It is shown that the source of a nucleus for traffic breakdown is the solely difference between empirical spontaneous and induced traffic breakdowns at a highway bottleneck. Microscopic traffic simulations with a stochastic traffic flow model in the framework of three-phase theory explain the empirical findings. It turns out that in the most cases, a nucleus for empirical spontaneous traffic breakdown occurs through an interaction of one of waves in free flow with an empirical permanent speed disturbance localized at a highway bottleneck. The wave is a localized structure in free flow, in which the total flow rate is larger and the speed averaged across the highway is smaller than outside the wave. The waves in free flow appear due to oscilations in the percentage...

  8. A study of a main-road cellular automata traffic flow model

    黄乒花; 孔令江; 刘慕仁

    2002-01-01

    A main-road cellular automata traffic flow model on two dimensions is presented based on the Biham-Middleton-Levine traffic model. Its evolution equations are given and the self-organization and organization cooperation phenomenain this model are also studied by using computer simulation.

  9. Transition from Disorder to Order in Traffic Flow

    LI Ke-Ping; GAO Zi-You

    2004-01-01

    We propose a new technique to investigate the dynamical transitions among the traffic phases. A type of the control signals has been designated at a given site (signal point) of the single-lane highway. Under the effect of the control signal, the velocity of the vehicle that passes the signal point will be changed periodically. Our method is tested for the deterministic NaSch traffic model. The simulation results demonstrate that the disorder states in the deterministic NaSch traffic model can be suppressed, and the different types of periodic states would occur.

  10. The Traffic Adaptive Data Dissemination (TrAD) Protocol for both Urban and Highway Scenarios.

    Tian, Bin; Hou, Kun Mean; Zhou, Haiying

    2016-01-01

    The worldwide economic cost of road crashes and injuries is estimated to be US$518 billion per year and the annual congestion cost in France is estimated to be €5.9 billion. Vehicular Ad hoc Networks (VANETs) are one solution to improve transport features such as traffic safety, traffic jam and infotainment on wheels, where a great number of event-driven messages need to be disseminated in a timely way in a region of interest. In comparison with traditional wireless networks, VANETs have to consider the highly dynamic network topology and lossy links due to node mobility. Inter-Vehicle Communication (IVC) protocols are the keystone of VANETs. According to our survey, most of the proposed IVC protocols focus on either highway or urban scenarios, but not on both. Furthermore, too few protocols, considering both scenarios, can achieve high performance. In this paper, an infrastructure-less Traffic Adaptive data Dissemination (TrAD) protocol which takes into account road traffic and network traffic status for both highway and urban scenarios will be presented. TrAD has double broadcast suppression techniques and is designed to adapt efficiently to the irregular road topology. The performance of the TrAD protocol was evaluated quantitatively by means of realistic simulations taking into account different real road maps, traffic routes and vehicular densities. The obtained simulation results show that TrAD is more efficient in terms of packet delivery ratio, number of transmissions and delay in comparison with the performance of three well-known reference protocols. Moreover, TrAD can also tolerate a reasonable degree of GPS drift and still achieve efficient data dissemination. PMID:27338393