Download or read book Development of Roundabout Crash Prediction Models and Methods written by and published by . This book was released on 2018 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of Roundabout Crash Prediction Models and Methods provides crash prediction models that quantify the expected safety performance of roundabouts for motorized and non-motorized road users. Safety performance factors (SPF) and crash modification factors (CMF) are predictive models that estimate expected crash frequencies. These models are used to identify locations where crash rates are higher than expected, to estimate safety benefits of a proposed project, and to compare the safety benefits of design alternatives. SPF and CMF models may help identify and prioritize locations for safety improvements, compare project alternatives by their expected safety benefits, and guide detailed design decisions to optimize safety. Research indicates that roundabouts provide substantial reductions in crashes, and this report determines SPF and CMF specifications for roundabouts.
Download or read book Roundabout Crash Prediction Models written by and published by . This book was released on 2009 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Roundabouts in the United States written by Lee Rodegerdts and published by Transportation Research Board. This book was released on 2007 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Research sponsored by the American Association of State Highway and Transporation Officials in cooperation with the Federal Highway Administration."
Download or read book Roundabouts written by Lee August Rodegerdts and published by Transportation Research Board. This book was released on 2010 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Report 672: Roundabouts: An Informational Guide - Second Edition explores the planning, design, construction, maintenance, and operation of roundabouts. The report also addresses issues that may be useful in helping to explain the trade-offs associated with roundabouts. This report updates the U.S. Federal Highway Administration's Roundabouts: An Informational Guide, based on experience gained in the United States since that guide was published in 2000.
Download or read book Roundabout Crash Prediction Models written by Shane Turner and published by . This book was released on 2009 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Crash Prediction Models for Short term Durations written by Mohamed Ahmed Abdel-Aty and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Crash prediction methods, which are used to identify crash hotspots or crash severity, consist of safety performance functions (SPFs), crash modification factors, and severity distribution functions. These tools use annual average daily traffic data along with geometric and operational characteristics to predict the annual average crash frequency. [This report] provides roadway safety practitioners within state departments of transportation with short-term crash prediction models to be used for estimating safety performance."--Publisher's website.
Download or read book Roundabouts written by Jim C. Lee and published by . This book was released on 2003 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: The roundabouts controlling traffic at the I-17/Happy Valley Road interchange represent Arizona's first application of modern roundabout traffic control in this manner. The construction of roundabouts at this interchange location served to alleviate past congestion and safety issues by reducing off-ramp queues and reducing speeds in the area of the I-17 off-ramp termini. The use of the roundabouts offered flexibility in addressing the complicated traffic interactions of the freeway on- and off-ramps, two-way frontage roads, and Happy Valley Road. Based on this milestone and the overall unique application of roundabout design and function at this particular interchange, the I-17/Happy Valley Road roundabouts were studied to help identify possible improvements that could be incorporated at this location and into future Arizona Department of Transportation roundabout initiatives. The anticipated benefits of the improvements include, but are not limited to, more efficient traffic operations, reduced costs (on average), increased capacity, and improved safety (due to overall slower speeds through the roundabout). The main objectives of this research project include literature review of other state guidelines; evaluation of the roundabouts' design parameters and operation as they relate to capacity and safety; collecting public opinion; and guidelines development. The deliverables of the research project include recommended improvements for the existing roundabouts involving geometric, striping, and signing modifications. Also, the research project culminates in guidelines for the selection, evaluation, and design of roundabouts which provide details on the facets of roundabout use as it relates to Arizona.
Download or read book Understanding and Communicating Reliability of Crash Prediction Models written by and published by . This book was released on 2021 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding and communicating consistently reliable crash prediction results are critical to credible analysis and to overcome barriers for some transportation agencies or professionals utilizing these models. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 303: Understanding and Communicating Reliability of Crash Prediction Models provides guidance on being able to assess and understand the reliability of Crash Prediction Models. This document is supplemental to NCHRP Research Report 983: Reliability of Crash Prediction Models: A Guide for Quantifying and Improving the Reliability of Model Results.
Download or read book Macro Level Analysis of Safety Planning and Crash Prediction Models written by and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Highway Safety Manual (HSM) is a tool that helps transportation agencies make data-driven decisions about safety. It includes methods for quantifying safety performance and predicting crash frequencies. The HSM is currently being updated to include macro-level crash prediction models, which can be used to assess safety trends at a regional or national level. NCHRP Web-Only Document 348: Macro-Level Analysis of Safety Planning and Crash Prediction Models: A Guide, from TRB's National Cooperative Highway Research Program, provides guidance on how to use a spreadsheet tool developed during this project. The document is supplemental to NCHRP Research Report 1044: Development and Application of Quantitative Macro-Level Safety Prediction Models.
Download or read book Network based Highway Crash Prediction Using Geographic Information Systems written by and published by . This book was released on 2007 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Roundabouts as Safe and Modern Solutions in Transport Networks and Systems written by Elżbieta Macioszek and published by Springer. This book was released on 2018-07-31 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a collection of guidelines that will be particularly useful to those making decisions concerning roundabouts as safe and modern solutions in transport networks and systems. The decision-making support systems described here will interest those who face the challenge of finding solutions to problems concerning modern transport systems on a daily basis. Consequently, the book is chiefly intended for local authorities involved in planning and preparing development strategies for specific transport-related issues (in both urban and regional contexts), as well as for representatives of business and industry who are directly engaged in the implementation of traffic engineering solutions. The guidelines provided in the respective chapters help to address the given problem soundly, and to simplify the selection of an appropriate strategy. The topics covered include traffic conditions and the performance of single-lane, two-lane and turbo roundabouts, road traffic safety analysis, analysis of road traffic safety improvements, surrogate safety measures at roundabouts, analysis of pedestrian behavior at pedestrian crossings with public transport vehicles, methods for assessing vehicle motion trajectory at single-lane roundabouts using visual techniques, making compact two-lane roundabouts effective for vulnerable road users, concepts for wireless electric vehicle charging near roundabouts, work zones, and temporary traffic control at roundabouts. Since the book also considers new approaches to theoretical models (including modeling roundabout capacity, models of critical gaps and follow-up headways for turbo roundabouts, and estimating roundabout delay while taking into account pedestrian impact), it will also appeal to researchers and scientists studying these problems. The book gathers selected papers presented at the 15th Scientific and Technical Conference “Transport Systems. Theory and Practice”, organized by the Department of Transport Systems and Traffic Engineering, Silesian University of Technology in Katowice, Poland on September 17–19, 2018.
Download or read book Roundabouts written by Bruce W. Robinson and published by . This book was released on 2000 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: The guidance supplied in this document, Roundabouts: an informational guide, is based on established international and U.S. practices and is supplemented by recent research. The guide is comprehensive in recognition of the diverse needs of transportation professionals and the public for introductory material through design detail, as well as the wide range of potential applications of roundabout intersections. The following topics are addressed: definition of a roundabout and what distinguishes roundabouts from traffic circles; public acceptance and legal issues associated with roundabouts; consideration of all user modes, including heavy vehicles, buses, transit, bicycles, and pedestrians; a methodology for identifying appropriate sites for roundabouts and the range of conditions for which roundabouts offer optimal performance: methodologies for estimating roundabout capacity, delays, and queues with reference to the Highway Capacity Manual; design principles and guidance on safety and geometric design, with reference to applicable national standards such as the AASHTO Policy on Geometric Design of Highways and Streets; guidelines for control features such as signing and pavement markings, with reference to the Manual on Uniform Traffic Control Devices; illumination; and landscaping.
Download or read book A Compendium of Effective Evidence based Best Practices in Prevention of Neurotrauma written by Richard Volpe and published by University of Toronto Press. This book was released on 2002-01-01 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Portrays examples of injury prevention practices that have the potential to reduce the incidence of neurotauma injuries, and by providing a detailed methodology that is effective in identifying innovative best practices.
Download or read book Improved Prediction Models for Crash Types and Crash Severities written by and published by . This book was released on 2021 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: The release of the Highway Safety Manual (HSM) by the American Association of State Highway and Transportation Officials (AASHTO) in 2010 was a landmark event in the practice of road safety analysis. Before it, the United States had no central repository for information about quantitative road safety analysis methodology. The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 295: Improved Prediction Models for Crash Types and Crash Severities describes efforts to develop improved crash prediction methods for crash type and severity for the three facility types covered in the HSM—specifically, two‐lane rural highways, multilane rural highways, and urban/suburban arterials. Supplemental materials to the Web-Only Document include Appendices A, B, and C (Average Condition Models, Crash Severities – Ordered Probit Fractional Split Modeling Approach, and Draft Content for Highway Safety Manual, 2nd Edition).
Download or read book Development and Application of Crash Severity Models for Highway Safety written by and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first edition of the Highway Safety Manual has provided methods and procedures for estimating total crashes, crashes by type, and crashes by severity at the site level, project level and corridor level. Crash prediction models are critical in the entire safety management system recommended by HSM, including network screening, economic analysis, project prioritization, and safety effectiveness evaluation. NCHRP Web-Only Document 351: Development and Application of Crash Severity Models for Highway Safety: Conduct of Research Report, from TRB's National Cooperative Highway Research Program, is supplemental to NCHRP Research Report 1047: Development and Application of Crash Severity Models for Highway Safety: User Guidelines. The document seeks to identify gaps and opportunities in the current severity prediction/estimation procedures within the HSM, to develop and validate new severity models to address the gaps and opportunities, and to develop a guidance document that includes protocols for the use and application of severity-based models in a format suitable for possible adoption in the HSM.
Download or read book Improving Freeway Crash Prediction Models Using Disaggregate Flow State Information written by Nancy Dutta and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crash analysis methods typically use annual average daily traffic as an exposure measure, which can be too aggregate to capture the safety effects of variations in traffic flow and operations that occur throughout the day. Flow characteristics such as variation in speed and level of congestion play a significant role in crash occurrence and are not currently accounted for in the American Association of State Highway and Transportation Officials' Highway Safety Manual. This study developed a methodology for creating crash prediction models using traffic, geometric, and control information that is provided at sub-daily aggregation intervals. Data from 110 rural four-lane segments and 80 urban six-lane segments were used. The volume data used in this study came from detectors that collect data ranging from continuous counts throughout the year to counts from only a couple of weeks every other year (short counts). Speed data were collected from both point sensors and probe data provided by INRIX. The results showed that models that used data aggregated to an average hourly level reflected the variation in volume and speed throughout the day without compromising model quality. Crash predictions for urban segments underwent a 20% improvement in mean absolute deviation for total crashes and a 9% improvement for injury crashes when models using average hourly volume, geometry, and flow variables were compared to the model based on annual average daily traffic. Corresponding improvements over annual average daily traffic models for rural segments were 11% and 9%. Average hourly speed, standard deviation of hourly speed, and differences between speed limit and average speed had statistically significant relationships with crash frequency. For all models, prediction accuracy was improved across all validation measures of effectiveness when the speed components were added. The positive effect of flow variables was true irrespective of the speed data source. Further investigation revealed that the improvement achieved in model prediction by using a more inclusive and bigger dataset was larger than the effect of accounting for spatial/temporal data correlation. For rural hourly models, mean absolute deviation improved by 52% when short counts were added in comparison to the continuous count station only models. The respective value for urban segments was 58%. This means that using short count stations as a data source does not diminish the quality of the developed models. Thus, a combination of different volume data sources with good quality speed data can lessen the dependency on volume data quality without compromising performance. Although accounting for spatial and temporal correlation improved model performance, it provided smaller benefits than inclusion of the short count data in the models. This study showed that it is possible to develop a broadly transferable crash prediction methodology using hourly level volume and flow data that are currently widely available to transportation agencies. These models have a broad spectrum of potential applications that involve assessing safety effects of events and countermeasures that create recurring and non-recurring short-term fluctuations in traffic characteristics.
Download or read book Efficient and Interpretable Crash Prediction Models written by Thomas Véran and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Worldwide, highway accidents have important social and financial impacts. To reduce their frequency and gravity, crash prediction models (CPM) are used to identify hazardous roadway segments and to provide actionable clues about the associated risk factors. CPM are either interpretable-by-design parametric statistical models, in particular generalized linear models (GLM), or machine learning models with a large number of parameters without associated uncertainty estimates (e.g., ensemble of decision trees, support vector machine ...). When pondering high stake decisions, such as in the context of highway safety, field experts expect predictive models to be both effective and glass-box interpretable to help them deploy preventive safety actions. As such, we contribute to enhancing the predictive performance of parametric models while maintaining their interpretability. Our main contributions aim to achieve this goal in two steps. First, we introduce a supervised method to discover a partition of the original observations and build a hierarchical model above it. Second, we introduce two algorithmic approaches (viz., a polynomial neural network, and an extension of multi-objective symbolic regression) to discover highly discriminant non-linear transforms of the original variables. The former can handle correlations among groups of observations which usually lead to improvements in the quality of the models' predictions and of their interpretation. The latter, while remaining simple (e.g. first-order interactions), allow the models to capture more of the variability in the dependent variable. Experiments have been conducted on a highway safety dataset and on more than ten public datasets covering classification and regression tasks. They show promising results with our contributions outperforming traditional glass-box interpretable models while getting close to the best non-parametric models. Finally, we illustrate the benefits of our approach by introducing, on a realistic case study, an application we designed for highway safety experts.
