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Self-organizing traffic lights at multiple-street intersections  [PDF]
Carlos Gershenson,David A. Rosenblueth
Physics , 2011,
Abstract: Summary: Traffic light coordination is a complex problem. In this paper, we extend previous work on an abstract model of city traffic to allow for multiple street intersections. We test a self-organizing method in our model, showing that it is close to theoretical optima and superior to a traditional method of traffic light coordination. Abstract: The elementary cellular automaton following rule 184 can mimic particles flowing in one direction at a constant speed. This automaton can therefore model highway traffic. In a recent paper, we have incorporated intersections regulated by traffic lights to this model using exclusively elementary cellular automata. In such a paper, however, we only explored a rectangular grid. We now extend our model to more complex scenarios employing an hexagonal grid. This extension shows first that our model can readily incorporate multiple-way intersections and hence simulate complex scenarios. In addition, the current extension allows us to study and evaluate the behavior of two different kinds of traffic light controller for a grid of six-way streets allowing for either two or three street intersections: a traffic light that tries to adapt to the amount of traffic (which results in self-organizing traffic lights) and a system of synchronized traffic lights with coordinated rigid periods (sometimes called the "green wave" method). We observe a tradeoff between system capacity and topological complexity. The green wave method is unable to cope with the complexity of a higher-capacity scenario, while the self-organizing method is scalable, adapting to the complexity of a scenario and exploiting its maximum capacity. Additionally, in this paper we propose a benchmark, independent of methods and models, to measure the performance of a traffic light controller comparing it against a theoretical optimum.
Mathematical model of traffic flow on arteries with coordinated control system
城市协调控制主干路交通流模型

ZHANG Meng-meng,JIA Lei,
张萌萌
,贾磊

控制理论与应用 , 2011,
Abstract: Mathematical model of traffic flow on arteries with coordinated control system is a prerequisite for traffic forecasting, imulating and signal timing. A one-dimensional cellular automaton-model with improved open boundary conditions is used to simulate the traffic flow on arterial roads with coordinated control system. The model employs difference equations to describe dynamic behaviors of vehicles. The restriction on regularly spaced distribution of traffic signal lamps can be eliminated. Furthermore, the green-signal-ratio on every intersection can be chosen according to traffic flow fluctuations. The phase difference between adjacent intersections can be adjusted by green wave control. MATLAB is employed to simulate this model to analyze the impacts on mean velocity, density and volume of arterial traffic flow by the flow volume on the artery and the turning flow volumes from branches. Based on the results of simulation, a series of proposals for improving the arterial traffic situations are put forward.
Study on Optimization of Phase Offset at Adjacent Intersections  [cached]
Yuanli GU,Lei Yu
International Journal of Intelligent Systems and Applications , 2010,
Abstract: Optimization of the phase offset at adjacent intersections is the key parameter regarding coordinated control of traffic signal for adjacent intersections, which decides the effect of the coordinated control for adjacent intersections. According to characters of saturated traffic flow of Chinese urban road, this thesis establishes a model for optimization of phase offset for adjacent interactions and finds a solution from such model by adopting genetic algorithm. The model is verified by actual traffic flow datum of two adjacent signal intersections on Changan Avenue. Then a comparison is made between the optimization result of such model and that of the existing mathematical method and SYNCHRO model, which indicates that the model established by this thesis can reduce the delay suffered by vehicles at the intersections and increase the traffic efficiency of the intersections.
Multiple Derived Lagrangian Intersections  [PDF]
Oren Ben-Bassat
Mathematics , 2013,
Abstract: We give a new way to produce examples of Lagrangians in shifted symplectic derived stacks, based on multiple intersections. Specifically, we show that an m-fold fiber product of Lagrangians in a shifted symplectic derived stack its itself Lagrangian in a certain cyclic product of pairwise homotopy fiber products of the Lagrangians.
Telemetric control of traffic lights intersections aspect ratio in Ghana  [PDF]
Erwin Normanyo,Neville Dodoo-Quartey,Adetunde Isaac
Journal of Engineering and Applied Sciences , 2009,
Abstract: This paper presents the current operation and maintenance of traffic light intersections and the design of a telemetry system to monitor and control traffic light intersections in the Accra metropolis. Telemetry is a technology that allows the remote measurement and reporting of information of interest to the system designer or operator. The design of a telemetry system constitutes the selection of a suitable hardware system and the appropriate software for the design of a human machine interface (HMI) to monitor the state of traffic light intersections and taking appropriate actions to resolve faulty traffic light intersections.
PERFORMANCE EVALUATION OF ADVANCED TRAFFIC CONTROL SYSTEMS AT SIGNALISED INTERSECTIONS FAR FROM ADJACENT INTERSECTIONS  [cached]
A. Caroline Sutandi
Civil Engineering Dimension , 2007,
Abstract: Advanced Traffic Control Systems (ATCS) have been recognised as one of the most direct methods for relieving urban traffic congestion. However, the applications of the systems in large cities in developing countries are unique because road networks in these cities face more severe transportation problems than those in developed countries. Furthermore, some of signalised intersections lie close, but others far from adjacent intersections. The aim of this paper is to evaluate the performance of ATCS at intersections with far distance to adjacent intersections and to recommend how to improve traffic performance with given constraints of severe transportation problems. Road network in Bandung, Indonesia was used as a case study. Microscopic traffic simulation was conducted to evaluate the performance of ATCS. It is shown that on average, traffic performance measures under Fixed Time traffic control system were similar or better than those under ATCS. In conclusion, the application of ATCS at intersections far from adjacent intersections is not effective.
Delays at signalised intersections with exhaustive traffic control  [PDF]
Marko Boon,Ivo Adan,Erik Winands,Doug Down
Computer Science , 2014, DOI: 10.1017/S0269964812000058
Abstract: In this paper we study a traffic intersection with vehicle-actuated traffic signal control. Traffic lights stay green until all lanes within a group are emptied. Assuming general renewal arrival processes, we derive exact limiting distributions of the delays under Heavy Traffic (HT) conditions. Furthermore, we derive the Light Traffic (LT) limit of the mean delays for intersections with Poisson arrivals, and develop a heuristic adaptation of this limit to capture the LT behaviour for other interarrival-time distributions. We combine the LT and HT results to develop closed-form approximations for the mean delays of vehicles in each lane. These closed-form approximations are quite accurate, very insightful and simple to implement.
Buffon type Problems with multiple intersections for regular lattices  [cached]
Vittoria Bonanzinga,Loredana Sorrenti
Atti della Accademia Peloritana dei Pericolanti : Classe di Scienze Fisiche, Matematiche e Naturali , 2010,
Abstract: In this paper we study Buffon type problems with multiple intersections for lattices of equilateral triangles and a circle as test body.
Model of Traffic Speed-Flow Relationship at Signal Intersections  [PDF]
Yixin Chen
Open Journal of Applied Sciences (OJAppS) , 2017, DOI: 10.4236/ojapps.2017.76025
Abstract: Speed-flow relationship is the fundamental for the traffic simulation and traffic volume forecast. Traditional quadratic polynomial model can’t reflect the saturate flow at signal intersections. In order to determine the speed-flow relationship at signal intersections, the speed and time-headway of vehicles at two signal intersections were investigated and the accuracy of software used to get the speed was tested. After vehicle starting-up from queuing, the time-headway reduces gradually with the increase of speed. The relationship of power exponential function between speed and time-headway is formulated. Traffic volume can be calculated by the vehicle time-headway. Then the speed-flow relationship was developed and an S-shaped curve model was built in this paper. In the S-shaped curve model, traffic flow approaches to the saturate when the speed doesn’t increase. Thus, S-shaped curve model is better to describe the speed-flow relationship at signal intersection. The results can provide a reference to determine the parameters in traffic simulation and for the study of level of service of intersections.
Optimal Control and Coordination of Connected and Automated Vehicles at Urban Traffic Intersections  [PDF]
Yue J. Zhang,Andreas A. Malikopoulos,Christos G. Cassandras
Mathematics , 2015,
Abstract: We address the problem of coordinating online a continuous flow of connected and automated vehicles (CAVs) crossing two adjacent intersections in an urban area. We present a decentralized optimal control framework whose solution yields for each vehicle the optimal acceleration/deceleration at any time in the sense of minimizing fuel consumption. The solution allows the vehicles to cross the intersections without the use of traffic lights, without creating congestion on the connecting road, and under the hard safety constraint of collision avoidance. The effectiveness of the proposed solution (omitting some constraints) is validated through simulation in VISSIM considering two intersections located in downtown Boston, and it is shown that coordination of CAVs can reduce significantly both fuel consumption and travel time.
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