incident detection algorithms, which are an essential part of traffic management systems, have been studied for several decades, but the research focus has primarily been on algorithms for incidentdetection on freewa...
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incident detection algorithms, which are an essential part of traffic management systems, have been studied for several decades, but the research focus has primarily been on algorithms for incidentdetection on freeways and other free-flowing roads. When applied on arterial roads, the achievement of stable performance and scalability are major challenges when developing an effective incident detection algorithm. In this research, the authors propose an incident detection algorithm that utilizes travel time and traffic volume samples generated from a Bluetooth-based wireless vehicle reidentification system that has been implemented on arterial roads. The proposed algorithm is based on a moving average over time, which can recognize sample travel time and traffic volume patterns resulting from incidents. The use of a moving average overcomes limitations resulting from sparse travel time sample data collected. Within the algorithm, a threshold strategy is applied that makes the algorithm easy to implement and transfer, which is an important requirement for practitioners. The proposed algorithm is evaluated using reported accident data and the insight of two traffic engineers, and provides a good balance between detection rate and false-alarm rate.
Even though incident detection algorithms are designed and implemented for quickly detecting incidents, the criterion of mean detection delay has hardly been well defined and utilized in developing and evaluating inci...
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Even though incident detection algorithms are designed and implemented for quickly detecting incidents, the criterion of mean detection delay has hardly been well defined and utilized in developing and evaluating incident detection algorithms. In addition, most incident detection algorithms do not have an optimal property in terms of detection delay with respect to false alarm rate. In the study presented in this paper, the incidentdetection problem was formulated as an optimization problem. To implement the algorithm, called the CUSUM algorithm that was derived from the optimization formulation of the incidentdetection problem, a simplified procedure was developed. Based on this procedure, three varieties of the CUSUM algorithm were developed and tested based on real incident data against a newly defined criterion for mean detection delay. Selected incident detection algorithms were also compared with the CUSUM algorithms. The comparison demonstrates the superiority of the CUSUM algorithms against other selected algorithms in reducing detection delay while maintaining an acceptable detection rate. (C) 2003 Elsevier Ltd. All rights reserved.
This paper presents an application of the wavelet technique to freeway incidentdetection because wavelet techniques have demonstrated superior performance in detecting changes in signals in electrical engineering. Un...
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This paper presents an application of the wavelet technique to freeway incidentdetection because wavelet techniques have demonstrated superior performance in detecting changes in signals in electrical engineering. Unlike the existing wavelet incident detection algorithm, where the wavelet technique is utilized to denoise data before the data is input into an algorithm, this paper presents a different approach in the application of the wavelet technique to incidentdetection. In this approach, the features that are extracted from traffic measurements by using wavelet transformation are directly utilized in detecting changes in traffic flow. It is shown in the paper that the extracted features from traffic measurements in incident conditions are significantly different from those in normal conditions. This characteristic of the wavelet technique was used in developing the wavelet incident detection algorithm in this study. The algorithm was evaluated in comparison with the multi-layer feed-forward neural network, probabilistic neural network, radial basis function neural network, California and low-pass filtering algorithms. The test results indicate that the wavelet incident detection algorithm performs better than other algorithms, demonstrating its potential for practical application. (C) 2003 Elsevier Ltd. All rights reserved.
Existing freeway and signalized arterial street incident detection algorithms were investigated to determine their merit for use on urban arterial streets. Based on this investigation, a Kalman filtering algorithm was...
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Existing freeway and signalized arterial street incident detection algorithms were investigated to determine their merit for use on urban arterial streets. Based on this investigation, a Kalman filtering algorithm was modified to recursively filter and update aggregate traffic flow and speed data to estimate true values. A test using measured arterial street data at a signalized intersection shows good tracking ability on these traffic variables over time. A test using data from an incident on an arterial street also confirmed that this algorithm has good potential for arterial street incidentdetection.
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