Use of Harsh-braking Data from Connected Vehicles as a Surrogate Safety Measure - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Use of Harsh-braking Data from Connected Vehicles as a Surrogate Safety Measure write by Nathaniel Patrick Edelmann. This book was released on 2022. Use of Harsh-braking Data from Connected Vehicles as a Surrogate Safety Measure available in PDF, EPUB and Kindle. "Traffic safety may be analyzed with the use of surrogate safety measures, measures of safety that do not incorporate collision data but rather rely on the concept of traffic conflicts. Use of these measures provides several benefits over use of more traditional analysis methods with historical crash data. Surrogate measures eliminate the need to wait for crashes to occur to conduct a safety analysis. The amount of time required for enough crash data to accumulate can be significant, delaying safety analyses. Similarly, these measures allow for safety analysis to be conducted prior to crashes occurring, potentially calling attention to hazardous areas which may be altered to prevent crashes. In addition to these benefits, traffic conflicts occur much more frequently than collisions, generating many more data points which in turn make statistical methods of analysis more effective. Evaluating surrogate safety measures for a particular transportation network is most effectively done with the use of traffic microsimulation or with connected vehicle data. Traffic microsimulation (such as the use of PTV VISSIM) will generate kinematic data that may then be used for computation of surrogate safety measures. A significant amount of research has been done on this topic, resulting in the establishment of algorithms for calculation of several different surrogate measures and validation of these measures. Kinematic data from connected vehicles has also been used for the calculation of surrogate safety measures. One data point collected by connected vehicles is harsh braking events which could serve as a surrogate safety measure. Because drivers usually brake more gently if given the opportunity to do so, harsh braking events indicate that a traffic conflict has occurred or is about to occur. Such events take away the driver’s opportunity to brake gently. This research establishes statistical models which relate harsh braking events to crashes on intersections and segments in Salt Lake City, Utah. The findings indicate that harsh braking events have the effect of reducing expected crashes because they represent traffic conflicts which were remedied through the use of harsh braking as an evasive action. The presence of schools and the presence of left turn lanes were also found to be statistically significant crash predictors. In addition to this research work a paper outlining the existing state of safety analysis with surrogate safety measures and evaluating the usefulness and practicality of various existing measures is presented."--Boise State University ScholarWorks.
Real-time Traffic Safety Evaluation in the Context of Connected Vehicles and Mobile Sensing
Real-time Traffic Safety Evaluation in the Context of Connected Vehicles and Mobile Sensing - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Real-time Traffic Safety Evaluation in the Context of Connected Vehicles and Mobile Sensing write by Pei Li. This book was released on 2021. Real-time Traffic Safety Evaluation in the Context of Connected Vehicles and Mobile Sensing available in PDF, EPUB and Kindle. 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.
Optimal Braking Patterns and Forces in Autonomous Safety-Critical Maneuvers
Optimal Braking Patterns and Forces in Autonomous Safety-Critical Maneuvers - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Optimal Braking Patterns and Forces in Autonomous Safety-Critical Maneuvers write by Victor Fors. This book was released on 2019-05-02. Optimal Braking Patterns and Forces in Autonomous Safety-Critical Maneuvers available in PDF, EPUB and Kindle. The trend of more advanced driver-assistance features and the development toward autonomous vehicles enable new possibilities in the area of active safety. With more information available in the vehicle about the surrounding traffic and the road ahead, there is the possibility of improved active-safety systems that make use of this information for stability control in safety-critical maneuvers. Such a system could adaptively make a trade-off between controlling the longitudinal, lateral, and rotational dynamics of the vehicle in such a way that the risk of collision is minimized. To support this development, the main aim of this licentiate thesis is to provide new insights into the optimal behavior for autonomous vehicles in safety-critical situations. The knowledge gained have the potential to be used in future vehicle control systems, which can perform maneuvers at-the-limit of vehicle capabilities. Stability control of a vehicle in autonomous safety-critical at-the-limit maneuvers is analyzed by the use of optimal control. Since analytical solutions of the studied optimal control problems are intractable, they are discretized and solved numerically. A formulation of an optimization criterion depending on a single interpolation parameter is introduced, which results in a continuous family of optimal coordinated steering and braking patterns. This formulation provides several new insights into the relation between different braking patterns for vehicles in at-the-limit maneuvers. The braking patterns bridge the gap between optimal lane-keeping control and optimal yaw control, and have the potential to be used for future active-safety systems that can adapt the level of braking to the situation at hand. A new illustration named attainable force volumes is introduced, which effectively shows how the trajectory of a vehicle maneuver relates to the attainable forces over the duration of the maneuver. It is shown that the optimal behavior develops on the boundary surface of the attainable force volume. Applied to lane-keeping control, this indicates a set of control principles similar to those analytically obtained for friction-limited particle models in earlier research, but is shown to result in vehicle behavior close to the globally optimal solution also for more complex models and scenarios.
Digitalisation for Sustainable Infrastructure: The Road Ahead
Digitalisation for Sustainable Infrastructure: The Road Ahead - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Digitalisation for Sustainable Infrastructure: The Road Ahead write by Carlo Secchi. This book was released on 2022-11-24. Digitalisation for Sustainable Infrastructure: The Road Ahead available in PDF, EPUB and Kindle. In today’s tumultuous and fast-changing times, digitalisation and technology are game changers in a wide range of sectors and have a tremendous impact on infrastructure. Roads, railways, electricity grids, aviation, and maritime transport are deeply affected by the digitaland technological transition, with gains in terms of competitiveness, cost-reduction, and safety. Digitalisation is also a key tool for fostering global commitment towards sustainability, but the race for digital infrastructure is also a geopolitical one. As the world’s largest economies are starting to adopt competitive strategies, a level playing field appears far from being agreed upon.Why are digitalisation and technology the core domains of global geopolitical competition? How are they changing the way infrastructure is built, operated, and maintained? To what extent will road, rail, air, and maritime transport change by virtue of digitalisation, artificial intelligence, and the Internet of Things? How to enhance cyber protection for critical infrastructure? What are the EU’s, US’ and China’sdigital strategies?
Enhanced Safety Evaluation Methods Using Connected Vehicle and Crash Data
Enhanced Safety Evaluation Methods Using Connected Vehicle and Crash Data - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Enhanced Safety Evaluation Methods Using Connected Vehicle and Crash Data write by Taehun Lee. This book was released on 2021. Enhanced Safety Evaluation Methods Using Connected Vehicle and Crash Data available in PDF, EPUB and Kindle.
