Entry-lane Capacity Analysis of Roundabouts in Texas Using VISSIM, SIDRA, and the Highway Capacity Manual PDF Download
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Author: Alison Fayre Mills Publisher: ISBN: Category : Languages : en Pages : 128
Book Description
Road safety and traffic congestion are two of the critical issues facing the transportation profession today. As a means to promote safety and efficiency at United States intersections modern roundabouts are becoming more and more common. Over the last ten years, roundabouts implementation methodologies have been developed using data collected at U.S. roundabouts. These methodologies were first published in National Cooperative Highway Report 572: Roundabouts in the United States and more recently in the second edition of the national roundabout guidelines. This work attempts to validate the use of these methodologies for roundabouts in the state of Texas and also enhance guidelines for evaluating roundabout operations by exploring the effects of exiting flow, origin-destination patterns, and mean speed on roundabout entry-lane capacity. Capacity results from VISSIM are compared to the Highway Capacity Manual entry-lane capacity curve and results from SIDRA.
Author: Alison Fayre Mills Publisher: ISBN: Category : Languages : en Pages : 128
Book Description
Road safety and traffic congestion are two of the critical issues facing the transportation profession today. As a means to promote safety and efficiency at United States intersections modern roundabouts are becoming more and more common. Over the last ten years, roundabouts implementation methodologies have been developed using data collected at U.S. roundabouts. These methodologies were first published in National Cooperative Highway Report 572: Roundabouts in the United States and more recently in the second edition of the national roundabout guidelines. This work attempts to validate the use of these methodologies for roundabouts in the state of Texas and also enhance guidelines for evaluating roundabout operations by exploring the effects of exiting flow, origin-destination patterns, and mean speed on roundabout entry-lane capacity. Capacity results from VISSIM are compared to the Highway Capacity Manual entry-lane capacity curve and results from SIDRA.
Author: Mohamad A. Shrayteh Publisher: ISBN: Category : Highway capacity Languages : en Pages : 340
Book Description
Compared to previous versions of the manual, the Highway Capacity Manual 2010 has provided more comprehensive capacity models for single and multilane roundabouts. The Highway Capacity Manual 2010 multilane roundabout capacity models are limited to two-by-two lanes, that is, two entry lanes and two circulating lanes. These capacity models are not valid for the three-by-three-lane roundabouts (three entry lanes and three circulating lanes) due to different traffic flow characteristics and features. This limitation of the Highway Capacity Manual 2010 model is also clearly mentioned in the manual. In this research, capacity models and curves were developed for three-by-three-lane roundabouts. More than 168 hours of video recordings were done on 12 three-by-three-lane roundabouts. The extracted data from the video recordings was used to understand the traffic operations and to develop the capacity models. It was found that lane utilization of the outermost circulating lane was low, and drivers preferred to use the middle entry lane for through movements as compared to the other two lanes. Based on the performance and usefulness, exponential regression models were selected for capacity estimation. The capacity curves were developed for the entry approach and for each entry lane of the three-by-three-lane roundabout. These models were used to estimate the follow-up headway and critical gap. The output of the proposed models showed that the entry volume decreases with the increase of the circulating flow at the three-by-three-lane roundabouts. The proposed models were also validated using a microscopic traffic-simulation model. A close association was found between outputs from both models. Transportation engineers can use the vii capacity models and curves presented in this research to perform the three-by-three-lane roundabout capacity analysis. Keywords: Three-by-three-lane roundabout, multilane roundabout, VisSim, capacity models, capacity curves, conflict areas.
Author: Abdullah Ayed F. Alqahtani Publisher: ISBN: Category : Simulation methods Languages : en Pages : 76
Book Description
According to the Washington State Department of Transportation (WSDOT), the use of roundabouts has been increasing due to its numerous benefits. Compared to other types of intersection (conventional) controls, a roundabout improves traffic safety, reduces delays, lessens the severity of crashes, improves traffic flow, and minimizes maintenance costs. The Federal Highway Administration (FHWA) report that in some previous study findings the injury and fatality crashes were reduced by 78-82% after converting signalized intersections to roundabouts. This study used data from the City of Fairborn, Ohio, for a project where they were preparing to replace a 50-years old signalized intersection (at Kauffman Avenue and Colonel Glenn Highway) with a modern roundabout. This signalized intersection experienced 18 crashes between 2013 and 2015. The modern roundabout was scheduled to be constructed in 2019 by the City of Fairborn, and it was designed with three legs (similar to the existing intersection layout), with three entries, three exits, and one circulating lane. Two software programs were used in this study, which are RODEL and Highway Capacity Software (HCS7), and two manual methods were also used, which are 2010 Federal Highway Administration method (Roundabouts: An Informational Guide) and 2016 Highway Capacity Manual (HCM 6). The main aim of this study was to compare capacity analysis results to the same data inputs among all methods. The results from this study are helpful in explaining the performance of each method and provide an understanding of analyzing roundabout capacity. The comparative results for each method include capacity, volume-to-capacity ratio, control delay, level of service (LOS), 95th percentile queue length for each approach/lane, and the entire intersection control delay and LOS. The results show that RODEL (geometric model) predicted the largest capacity, the smallest volume-to-capacity, the lowest delay, the best LOS, the shortest 95% queue length, and the lowest delay and best LOS for entire intersection. This supports the conclusions of previous studies. The FHWA 2010 results were quite the opposite; estimated the lowest capacity for the same traffic and geometric inputs, largest queues, delays and volume-to-capacity ratio. The results from HCS7, 2016 HCM (HCM 6), 2010 FHWA and RODEL (HCM 2016 model) were similar because they use the same methodology. HCS7 software automates the HCM6 methodologies.
Author: Raffaele Mauro Publisher: Springer Science & Business Media ISBN: 3642045510 Category : Technology & Engineering Languages : en Pages : 168
Book Description
Roundabouts have become one of the most significant traffic control measures because they are generally statistically safer and more efficient than traditional at grade intersections. This book is dedicated to the evaluation of the operating conditions of roundabouts. In five parts, it thoroughly illustrates the calculation of the capacity, including reliability, and waiting phenomena parameters, such as the times spent in the system and queue lengths. Fully worked examples are included throughout the chapters, with detailed explanations.
Author: National Research Council (U.S.). Highway Research Board. Committee on Highway Capacity Publisher: ISBN: Category : Roads Languages : en Pages : 168
Author: Bruce W. Robinson Publisher: ISBN: Category : Roads Languages : en Pages : 292
Book Description
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.
Author: Richard N. Cardwell Publisher: ISBN: Category : Highway capacity Languages : en Pages : 0
Book Description
"A technique, which will be discussed in this paper, has been devised to rate a rural two-lane highway using methods, tables and equations from the 1965 edition of the The highway capacity manual and from the Texas Highway Department design manual. ... I've called this technique 'capacity analysis'"--Leaf 3.
Author: Alison Fayre Mills
Author: Alison Fayre Mills
Author: Mohamad A. Shrayteh
Author: Abdullah Ayed F. Alqahtani
Author: Raffaele Mauro
Author: National Research Council (U.S.). Highway Research Board. Committee on Highway Capacity
Author: Bruce W. Robinson
Author: Richard N. Cardwell
Author: Jack E. Leisch
Author: Clyde E. Lee
Author: