Dynamic Variable Speed Limit Control PDF Download

Author: Petros A. Ioannou
Publisher:
ISBN:
Category : Traffic flow
Languages : en
Pages : 91

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Author: Ryan J. Cunningham
Publisher:
ISBN:
Category : Intelligent transportation systems
Languages : en
Pages : 231

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Book Description
In the free-flow condition (60% loading), the best treatments involved the more liberal threshold for defining homogeneous speed zones (5 mph) and the more liberal implementation distance (entire speed zone), as well as a minimum time period of 10 minutes. This treatment was actually shown to significantly reduce the network travel time by 0.8%. It was also shown that this particular implementation strategy (lowering upstream, raising downstream) is wholly resistant to the effects of crash migration in the 60% loading scenario. In the condition approaching congestion (80% loading), the best treatment again involved the more liberal threshold for homogeneous speed zones (5 mph), yet the more conservative implementation distance (half the speed zone), along with a minimum time period of 5 minutes. This particular treatment arose as the best due to its unique capability to resist the increasing effects of crash migration in the 80% loading scenario. It was shown that the treatments implementing over half the speed zone were more robust against crash migration than other treatments. The best treatment exemplified the greatest benefit in reduced sections and the greatest resistance to crash migration in other sections. In the 80% loading scenario, the best treatment increased the network travel time by less than 0.4%, which is deemed acceptable. No treatment was found to successfully reduce the rear-end and lane-change crash risks in the congested traffic condition (90% loading). This is attributed to the fact that, in the congested state, the speed of vehicles is subject to the surrounding traffic conditions and not to the posted speed limit. Therefore, changing the posted speed limit does not affect the speed of vehicles in a desirable manner. These conclusions agree with Dilmore (2005).

Author: András Hegyi
Publisher:
ISBN:
Category : Express highways
Languages : en
Pages : 236

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Author: Europump & the Hydraulic Europump & the Hydraulic Insti
Publisher: Elsevier
ISBN: 0080520464
Category : Technology & Engineering
Languages : en
Pages : 185

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Book Description
Prepared by industry experts from the pump, motor and drive industries under the auspices of Europump and the Hydraulic Institute, this reference book provides a comprehensive guide to variable speed pumping.It includes technical descriptions of pumping systems and their components, and guides the reader through the evaluation of different speed control options.Case studies help illustrate the life cycle cost savings and process improvements that appropriate variable speed pumping can deliver.·Authoritative, global reference to Variable Speed Pumping, by Europump and the Hydraulic Institute·Combines the technical knowledge of pump, motor and control systems in one guide·Brings together all the concepts, metrics and step-by-step decision-making support you need to help you decide which VSD strategies are most appropriate·Will help you design and specify pumping applications that minimise life-cycle costs

Author: Martin Treiber
Publisher: Springer Science & Business Media
ISBN: 3642324592
Category : Science
Languages : en
Pages : 505

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Book Description
This textbook provides a comprehensive and instructive coverage of vehicular traffic flow dynamics and modeling. It makes this fascinating interdisciplinary topic, which to date was only documented in parts by specialized monographs, accessible to a broad readership. Numerous figures and problems with solutions help the reader to quickly understand and practice the presented concepts. This book is targeted at students of physics and traffic engineering and, more generally, also at students and professionals in computer science, mathematics, and interdisciplinary topics. It also offers material for project work in programming and simulation at college and university level. The main part, after presenting different categories of traffic data, is devoted to a mathematical description of the dynamics of traffic flow, covering macroscopic models which describe traffic in terms of density, as well as microscopic many-particle models in which each particle corresponds to a vehicle and its driver. Focus chapters on traffic instabilities and model calibration/validation present these topics in a novel and systematic way. Finally, the theoretical framework is shown at work in selected applications such as traffic-state and travel-time estimation, intelligent transportation systems, traffic operations management, and a detailed physics-based model for fuel consumption and emissions.

Author: Ellen F. Grumert
Publisher: Linköping University Electronic Press
ISBN: 9176853411
Category :
Languages : en
Pages : 93

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Book Description
Motorway traffic management systems are useful for improving the traffic conditions on urban motorways. One of the most common motorway traffic management systems are variable speed limit systems. These systems adapt the speed limits based on the prevailing traffic conditions measured by roadside detectors and recommended or compulsory speed limits are shown on variable message signs installed on gantries over the road.Thesystems consist of three parts; the control algorithm used to determine which speed limit to be displayed, a method for estimating the traffic conditions to be used as input for the control algorithm and the infrastructure for application of the variable speed limits. The goal of the systems is often to increase safety or efficiency. Recent development in the field of connected vehicles have opened up for a new type of data source, as the status of a connected vehicle and its surroundings can be communicated at arbitrary locations. Hence, by the use of connected vehicles in variable speed limit systems there is a potential of reducing the amount of roadside equipment. It is even possible to control the connected vehicles towards the current speed limit without the use of variable message signs. This allows for the application of variable speed limits at arbitrary locations. The aim of this thesis is to examine how connected vehicles can be used to improve the efficiency of variable speed limit systems. The thesis contribute with new and improved methods using connected vehicles in all three parts of a variable speed limit system. The suggested methods are evaluated by microscopic traffic simulation. The overall conclusion is that the use of connected vehicles in variable speed limit systems can contribute to improvements in traffic efficiency compared to existing systems. The six papers included in the thesis can be summarized as follows. First, it is shown that traditional variable speed limit systems can be effective for improving the traffic conditions on the motorway and the results can be comparable to more costly alterations by reconstruction of the infrastructure to increase the capacity. Next, the usefulness of connected vehicles for application and control of the speed limits in an existing variable speed limit system is investigated. It is concluded that the design of the control algorithm and the accuracy of the estimated traffic conditions have a great effect on the final outcome of the system. The design of the control algorithm is then examined by evaluation of a number of control algorithms with respect to safety, efficiency and environmental impacts. The main benefits and drawbacks of the algorithms are highlighted and desirable characteristics to include when designing a control algorithm are identified. In two studies, methods making use of connected vehicles for estimating the traffic conditions are proposed. The results show that connected vehicles are useful for improving the accuracy of the estimated traffic conditions through the inclusion of more detailed information and information at locations where detector measurements are not available. Finally, a variable speed limit system is proposed in which connected vehicles play a central role in the estimation of the traffic conditions, as well as in the control algorithm and for application of the speed limit. The system is shown to be useful for improving traffic efficiency during an incident at an arbitrary location along the controlled road.

Author: M. Papageorgiou
Publisher: Pergamon
ISBN:
Category : Business & Economics
Languages : en
Pages : 686

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Book Description
"The vast expansion of transportation systems on land, sea and in the air throughout the twentieth century has allowed for the development of economic, social and political connections across the globe undreamed of by our ancestors. However, this expansion has brought with it familiar problems such as airport delays and gridlock in our major cities. Fortunately, parallel progress in system science and information technology can provide us with the appropriate tools for rational and efficient solutions to our exponentially increasing transportation demands. This encyclopedia addresses the analysis, modelling and control of today's and tomorrow's traffic and transportation systems in a concise, comprehensive single volume. Well over 100 articles have been specially commissioned, or revised from the acclaimed Systems & Control Encyclopedia, to provide an overview of and first reference to models, control methods and practical aspects of all forms of traffic and transportation systems with a particular emphasis on efficient utilization of available infrastructure, plus a consideration of their historical, organizational, economic and social impacts. The Concise Encyclopedia of Traffic & Transportation Systems will be essential for professional and academic scientists and engineers in any discipline concerned with the movement of people and materials."--Book description, Amazon.com.

Author: Andreas Hegyi
Publisher:
ISBN:
Category :
Languages : en
Pages : 11

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When freeway traffic is dense, shock waves may appear. These shock waves result in longer travel times and in sudden large variations in the speeds of the vehicles, which could lead to unsafe situations. Dynamic speed limits can be used to eliminate or at least to reduce the effects of shock waves. However, coordination of the variable speed limits is necessary in order to prevent the occurrence of new shock waves and/or a negative impact on the traffic flows in other locations. In this paper, we present a model predictive control approach to optimally coordinate variable speed limits for freeway traffic with the aim of suppressing shock waves. First, we optimize continuous valued speed limits, such that the total travel time is minimal. Next, we include a safety constraint that prevents drivers from encountering speed limit drops larger than, e.g., 10 km/h. Furthermore, to get a better correspondence between the computed and applied control signals, we also consider discrete speed limits. We illustrate our approach with a benchmark problem.

Author: European Conference of Ministers of Transport
Publisher: OECD Publishing
ISBN: 9282103781
Category :
Languages : en
Pages : 286

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Speeding is the number one road safety problem in a large number of OECD/ECMT countries. It is responsible for around one third of the current, unacceptably high levels of road fatalities. Speeding has an impact not only on accidents but also on the ...

Author: British Road Federation
Publisher:
ISBN:
Category : Express highways
Languages : en
Pages : 264

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