https://sndbx.library.tuc.gr 410 1 10 DIAS Digital Library, Search Results for:Traffic Control https://sndbx.library.tuc.gr/view/58260 Authors:Papamichail Ioannis, Summary: https://sndbx.library.tuc.gr/view/58135 Authors:Ioannis Papamichail, Rodrigo Castelan Carlson, Papageorgiou Markos, Summary:Pesquisas recentes propuseram o controle do fluxo principal (CFP), realizado por limites de velocidade variáveis (LVV), como uma nova ferramenta para o gerenciamento do tráfego em rodovias. A eficiência da proposta foi demonstrada baseada em métodos sofisticados de controle ótimo que podem oferecer dificuldades em aplicações práticas em campo. O projeto de um controlador realimentado para CFP local é apresentado neste artigo, levando em consideração diversos requisitos e restrições práticas. O controlador projetado depende apenas de medições em tempo real de fácil obtenção e é robusto e apropriado para implantação em campo. O controlador é avaliado em simulação e comparado com os resultados de controle ótimo. Apesar de sua simplicidade, o desempenho do controlador aproxima os resultados do controle ótimo, mesmo levando em consideração diversas restrições práticas e de segurança, para diferentes cenários investigados. ABSTRACT Recent research has proposed Mainstream Traffic Flow Control (MTFC), enabled via variable speed limits (VSL), as a novel motorway traffic management tool and has demonstrated its efficiency based on sophisticated optimal control methods that may face difficulties in practical field implementations. A simple local MTFC feedback controller is designed in this paper, taking into account a number of practical requirements and restrictions. The MTFC controller relies only on readily available measurements and is therefore robust and suitable for field implementations. The controller is evaluated in simulations and compared to the optimal control results. Despite its simplicity, the new controller's performance is shown to approach the optimal control results, whilst considering several practical and safety restrictions, for a number of investigated scenarios. https://sndbx.library.tuc.gr/view/13896 Authors:Αμπουντώλας Κωνσταντίνος, Summary: https://sndbx.library.tuc.gr/view/12641 Authors:Πέτσα Αικατερίνη, Summary: https://sndbx.library.tuc.gr/view/61898 Authors:Wang, Y. , Papageorgiou Markos, Messmer, A., Summary:This paper addresses the design of traffic state estimator for traffic flow in motorway stretches. Motorway traffic dynamics is modelled by a stochastic macroscopic traffic flow model, while a traffic state estimator is designed based on the extended-Kalman-filtering methodology. Besides the estimation of normal traffic variables, the developed traffic state estimator deals with the on-line estimation of unknown model parameters. Simulation investigations were conducted to test the traffic state estimator under various traffic conditions in a motorway stretch. https://sndbx.library.tuc.gr/view/58255 Authors:Papamichail Ioannis, Papageorgiou Markos, Carlson R.C., Summary: https://sndbx.library.tuc.gr/view/58222 Authors:Papageorgiou Markos, Papamichail Ioannis, Kosmatopoulos Ilias, Wang Y., Kotsialos A., Summary: https://sndbx.library.tuc.gr/view/58261 Authors:Papamichail Ioannis, Papageorgiou Markos, Kosmatopoulos Ilias, Kouvelas Anastasios, Manolis. D., Summary: https://sndbx.library.tuc.gr/view/26790 Authors:Spiliopoulou Anastasia, Summary:Most metropolitan cities of developed countries have now an extensive network of urban and peri-urban freeways, which aims to provide virtually unlimited and fast mobility to road users around the metropolitan area. However, the increase of traffic demand, especially during the peak hours, and the occurrence of traffic incidents, leads to daily appearance of recurrent and non-recurrent freeway congestion which results in significant increase of travel times, increased fuel consumption, environmental pollution as well as reduced safety. The problem of freeway congestion in urban and peri-urban freeways cannot always be faced by expanding the existing infrastructure, for economic and environmental reasons; instead, efficient traffic control measures may be employed to mitigate the problem. However, the development of effective real-time traffic control measures implies the availability of suitable mathematical traffic flow models which may be used for the development and testing of the proposed control strategies. This thesis investigates the particular, but quite frequent, case of (recurrent) freeway congestion due to saturated off-ramps. This kind of congestion is difficult to deal with, and for this reason this frequent traffic flow degradation is rarely addressed in the traffic control literature. Moreover, within the traffic flow modeling literature there are, so far, no studies undertaking validation and comparison of different traffic flow models regarding the reproduction of traffic conditions in such areas. The aim of this research is to investigate traffic flow modeling and traffic control issues for congested freeway off-ramp areas. In particular, within this thesis the most popular discrete time-space macroscopic traffic flow models, namely the CTM and the METANET models, were validated and compared regarding the representation of traffic conditions at congested freeway off-ramp areas. The models were calibrated and validated using real traffic data from Attiki Odos freeway in Athens, and by employing various optimization methods. Apart from the modeling approach, various innovative real-time traffic control measures were developed for congested freeway off-ramp areas. In particular, two different cases were examined and suitable traffic control strategies were proposed for every case. In the first case, a hypothetical network was simulated, and various route diversion strategies were developed that aim to reroute the drivers through alternative routes, towards the same destination, preventing the off-ramp queue spillover and the creation of mainstream congestion. In the second case, a real traffic network was examined where recurrent freeway congestion is created due to congestion on the surface street network which propagates to the freeway mainstream through a saturated off-ramp. The network was simulated by use of microscopic simulation and a real-time merging traffic control algorithm was proposed that aims to maximize the surface street network throughput and at the same time to prevent the off-ramp queue from spilling back into the freeway mainstream. The simulation results, for both investigated cases, showed that the proposed traffic control measures can improve the prevailing traffic conditions, preventing the formation of mainstream congestion. Thus, they are both very promising for a field implementation. https://sndbx.library.tuc.gr/view/61913 Authors:Papageorgiou Markos, Summary:After a qualitative discussion of properties of on-line control schemes, such as closed-loop, open-loop and two-stage approach, for large-scale nonlinear plants, a multilayer structure is proposed for on-line control of nonlinear plants with measurable slow disturbances leading to good control performance even under occurrence of unexpected disturbances. The multilayer structure is applied to the freeway traffic control problem. Simulation results show the superiority of the resulting control actions compared to previous solutions.