Browsing by Author "Movius, Samantha Jane"

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    A case for implementing self-organising traffic signal control on South African roads
    (Southern African Institute for Industrial Engineering, 2019) Movius, Samantha Jane; Van Vuuren, Jan Harm
    ENGLISH ABSTRACT: Traffic signal optimisation may lead to the alleviation, to some extent, of urban traffic congestion, particularly by using real-time data rather than expected traffic flow data. Recent advances in radar technology have made it possible to observe detailed traffic flow data in and around roadway intersections in real time. The notion of self-organisation has relatively recently been proposed as a promising alternative to improve the effective allocation of green time, particularly under lighter traffic conditions. A fixed-time control strategy and seven self-organising algorithms are compared in a microscopic traffic simulation model of a provincial road in the Western Cape province of South Africa. Actual arrival rates are used as input for the model, while the algorithms are compared using six performance measure indicators, under both light and moderate traffic conditions. The results are used to make a case for the adoption of self-organising traffic signal control algorithms, especially under conditions of light to moderate traffic densities, since this can lead to significant improvements in traffic flow in terms of delay time, vehicle stops, and time spent travelling at unacceptably slow speeds through the road network.
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    Self-organisation in traffic Signal control algorithms
    (Stellenbosch : Stellenbosch University, 2018-03) Movius, Samantha Jane; Van Vuuren, J. H.; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.
    ENGLISH ABSTRACT: Two popular types of traffic signal control are fixed-time control and vehicle-actuated control. The latter method involves switching traffic signals based on detected traffic ows and thus offers more exibility than the former, which relies solely on cyclic, predetermined signal phases. The notion of self-organisation has relatively recently been proposed as an alternative approach towards improving traffic signal control, particularly during periods of light traffic flow, due to its flexible nature and its potential to result in emergent behaviour. The effectiveness of five self-organising traffic signal control strategies from the literature, as well as a fixed-time control strategy, have previously been compared in a simulated environment. Various shortcomings of three of these algorithms are pointed out in this dissertation and algorithmic improvements are suggested to remedy these defficiencies. The significant improvements resulting from these algorithmic modifications are then quantified by means of their implementation in a newly designed agent-based, microscopic traffic simulation model. Two novel self-organising traffic control algorithms are also proposed in this dissertation. These algorithms have been designed in such a way as to avoid certain shortcomings discovered in the aforementioned algorithms. The two novel algorithms, together with the improved versions of the three existing algorithms and the remaining pair of algorithms from the literature, are also subjected to thorough testing in the aforementioned simulation framework in terms of their propensity to facilitate the formation of green waves and to recover from various disruptions (such as road closures or abnormal traffic induced by large events) within the context of both gridded street networks and corridors with approaching side roads. All eight algorithms are finally implemented in a simulation model representing an existing road network in order to compare and evaluate the effectiveness of these algorithms within the context of a real-world scenario. It is found that the two newly proposed algorithms outperform existing self-organising traffic signal control algorithms under certain traffic conditions and road network topologies.