Self-organisation in traffic Signal control algorithms

[摘要] 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 approachtowards improving traffic signal control, particularly during periods of light trafficflow, 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, aswell 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 dissertationand algorithmic improvements are suggested to remedy these defficiencies. The significant improvementsresulting 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, arealso 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 arefinally 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 trafficsignal control algorithms under certain traffic conditions and road network topologies.

[发布机构] Stellenbosch University