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Author: Rongjie Yu Publisher: ISBN: Category : Languages : en Pages : 266
Book Description
The proposed VSL control strategy was tested for a mountainous freeway bottleneck area in the microscopic simulation software VISSIM. Safety impacts of the VSL system were quantified as crash risk improvements and speed homogeneity improvements. Moreover, three different driver compliance levels were modeled in VISSIM to monitor the sensitivity of VSL's safety impacts on driver compliance levels. Conclusions demonstrate that the proposed VSL system could effectively improve traffic safety by decreasing crash risk, enhancing speed homogeneity, and reducing travel time under both high and moderate driver compliance levels; while the VSL system does not have significant effects on traffic safety enhancement under the low compliance scenario. Future implementations of VSL control strategies and related research topics were also discussed.
Author: Rongjie Yu Publisher: ISBN: Category : Languages : en Pages : 266
Book Description
The proposed VSL control strategy was tested for a mountainous freeway bottleneck area in the microscopic simulation software VISSIM. Safety impacts of the VSL system were quantified as crash risk improvements and speed homogeneity improvements. Moreover, three different driver compliance levels were modeled in VISSIM to monitor the sensitivity of VSL's safety impacts on driver compliance levels. Conclusions demonstrate that the proposed VSL system could effectively improve traffic safety by decreasing crash risk, enhancing speed homogeneity, and reducing travel time under both high and moderate driver compliance levels; while the VSL system does not have significant effects on traffic safety enhancement under the low compliance scenario. Future implementations of VSL control strategies and related research topics were also discussed.
Author: Ellen F. Grumert Publisher: Linköping University Electronic Press ISBN: 9176853411 Category : Languages : en Pages : 93
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: European Conference of Ministers of Transport Publisher: OECD Publishing ISBN: 9282103781 Category : Languages : en Pages : 286
Book Description
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: Peter Eric Allaby Publisher: University of Waterloo ISBN: 9780494233702 Category : Languages : en Pages : 171
Book Description
The objectives of this thesis are: (1) to validate a real-time crash prediction model for a candidate section of freeway; (2) to develop a candidate VSLS control algorithm with potential for practical applications; (3) to evaluate the performance of the VSLS control strategy for a range of traffic conditions in terms of safety and travel time; and (4) to test the sensitivity of the VSLS impact results to modifications of the control algorithm.
Author: Publisher: ISBN: 9780309263214 Category : Traffic accident investigation Languages : en Pages : 191
Book Description
"This issue contains 20 papers concerned with the following aspects of highway safety data, analysis, and evaluation: relationship of traffic density, speed, and safety for setting variable speed limits; relationship of freeway flow parameters and safety for hard shoulder running; computer vision-based safety evaluations; safety intervention models; safety effectiveness of Super 2 highways; interaction of crash occurrence, mountainous freeway geometry, weather, and traffic data; real-time safety evaluation with automatic vehicle identification data; research on safety effects of actions; link between crash severity and crash avoidance maneuvers; roles of vehicle footprint, height, and weight in crash outcomes; safety assessment of road network structures; effect of collision aggregation on safety evaluations; integrating observational and traffic simulation models; crash frequency in work zones with focus on police enforcement; discretization of road networks for safety evaluation; application of different exposure measures in crash prediction models; long-term safety trends as a function of vehicle ownership; transferability of safety performance functions; land use entropy and accidents; and advisory speeds."--pub. desc.
Author: Dominique Lord Publisher: Emerald Group Publishing ISBN: 1786352249 Category : Transportation Languages : en Pages : 511
Book Description
This book increases the level of knowledge on road safety contexts, issues and challenges; shares what can currently be done to address the variety of issues; and points to what needs to be done to make further gains in road safety.
Author: Albinder Singh Dhindsa Publisher: ISBN: Category : Adaptive control systems Languages : en Pages : 220
Book Description
Recent research at UCF into defining surrogate measures for identifying crash prone conditions on freeways has led to the introduction of several statistical models which can flag such conditions with a good degree of accuracy. Outputs from these models have the potential to be used as real-time safety measures on freeways. They may also act as the basis for the evaluation of several intervention strategies that might help in the mitigation of risk of crashes.
Author: Pei Li Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Recently, with the development of connected vehicles and mobile sensing technologies, vehicle-based data become much easier to obtain. However, only few studies have investigated the application of this kind of novel data to real-time traffic safety evaluation. This dissertation aims to conduct a series of real-time traffic safety studies by integrating all kinds of available vehicle-based data sources. First, this dissertation developed a deep learning model for identifying vehicle maneuvers using data from smartphone sensors (i.e., accelerometer and gyroscope). The proposed model was robust and suitable for real-time application as it required less processing of smartphone sensor data compared with the existing studies. Besides, a semi-supervised learning algorithm was proposed to make use of the massive unlabeled sensor data. The proposed algorithm could alleviate the cost of data preparation and improve model transferability. Second, trajectory data from 300 buses were used to develop a real-time crash likelihood prediction model for urban arterials. Results from extensive experiments illustrated the feasibility of using novel vehicle trajectory data to predict real-time crash likelihood. Moreover, to improve the model’s performance, data fusion techniques were proposed to integrated trajectory data from various vehicle types. The proposed data fusion techniques significantly improved the accuracy of crash likelihood prediction in terms of sensitivity and false alarm rate. Third, to improve pedestrian and bicycle safety, different vehicle-based surrogate safety measures, such as hard acceleration, hard deceleration, and long stop, were proposed for evaluating pedestrian and bicycle safety using vehicle trajectory data. In summary, the results from this dissertation can be further applied to real-time safety applications (e.g., real-time crash likelihood prediction and visualization system) in the context of proactive traffic management.
Author: Rongjie Yu
Author: Rongjie Yu
Author: Ellen F. Grumert
Author: European Conference of Ministers of Transport
Author: Peter Eric Allaby
Author: 
Author: Dominique Lord
Author: Albinder Singh Dhindsa
Author: National Research Council (U.S.). Transportation Research Board
Author: András Hegyi
Author: Pei Li