An Analysis of the Feasibility of Roundabouts in the United States PDF Download

Author: Danielle S. Elisofon
Publisher:
ISBN:
Category :
Languages : en
Pages : 216

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Author: Lee Rodegerdts
Publisher: Transportation Research Board
ISBN: 0309098742
Category : Roads
Languages : en
Pages : 125

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"Research sponsored by the American Association of State Highway and Transporation Officials in cooperation with the Federal Highway Administration."

Author: Lee August Rodegerdts
Publisher: Transportation Research Board
ISBN: 0309155118
Category : Technology & Engineering
Languages : en
Pages : 407

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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.

Author: Quang Van Nguyen
Publisher:
ISBN:
Category :
Languages : en
Pages : 280

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Modern roundabouts have emerged as an increasingly popular design option for intersections throughout the United States (US), including California. Many states and cities are considering roundabouts as a viable alternative to other Traffic Control Devices (TCDs) and complex freeway interchanges to improve safety and operational efficiency at intersections. This research project analyzed the traffic feasibility design study and relevant field data of the roundabout intersection at Sheldon and Waterman Road in Elk Grove, California to specifically address the performance issues related to roundabout design and operation. The results in this study provides an overall picture of the operational performance of Sheldon and Waterman Road roundabout. It was found that there were statistically significant reductions in delay, queuing and proportion stopped at the study site after the installation of a modern roundabout. However, most of the measures of effectiveness are worse than those predicted in traffic feasibility design study.

Author:
Publisher:
ISBN:
Category : Arkansas State Highway 77 (Ark.)
Languages : en
Pages :

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Author: Bruce W. Robinson
Publisher:
ISBN:
Category : Roads
Languages : en
Pages : 292

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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: Mitsuru Saito (Ph.D., P.E.)
Publisher:
ISBN:
Category : Roads
Languages : en
Pages : 52

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Roundabouts have become increasingly popular in the United States in the past ten years. UDOT has recently installed three roundabouts on its state highways (Park City, Lehi, and Bloomington). Requests for installation of roundabouts replacing traditional intersections are expected to grow. However, UDOT does not have specific guidelines or criteria to judge whether roundabouts would be appropriate for the requested sites. The intent of this project was to summarize key isuues concerning roundabouts and develop a preliminary draft of design guidelines and policies that could be used for the implementation of a roundabout instead of some other form of intersection. Only a few state DOTs had design guidelines on roundabouts at the time of the study. US experiences have not been adequate for creating solid, universal design and analysis guidelines on roundabouts and at the time of the study, a multi-year NCHRP study has just started. The leading software packages used for the design, analysis, and simulation of roundabouts are originated in other countries, such as RODEL (United Kingdom) and aaSIDRA (Australia), where roundabouts have been in existence for many years and in numbers. The former is empirical based on thousands of roundabouts and the latter is based on the gap theory. Engineers do not agree on the best methodology for analysis, and therefore, various software packages with different methodologies exist. The HCS and Synchro 6.0 software programs have gap-based models and their analysis capabilities are not at the level of sophistication as the foreign counterparts. The NCHRP study (NCHRP) 3-65 Applying Roundabouts in the United States is about to be completed at the time of the publication of this report and it is recommended that this report be referenced.

Author: Alek Pochowski
Publisher:
ISBN:
Category : Roads
Languages : en
Pages :

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As the modern roundabout continues to grow in popularity within the United States, more states are considering or implementing statewide roundabout programs and policies. To assist states with the implementation of statewide roundabout programs and policies, an analytical review of statewide roundabout programs and policies was conducted through an examination of literature, interviews, and data pertaining to the construction of roundabouts. The roundabout policy type for each state and the District of Columbia was located, and assigned to a roundabout policy type based on the strength of the identified policy type. In addition, a series of per capita analyses of the statewide roundabout policies was performed, as was a qualitative SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis. The results of the analysis show that the strength of a statewide roundabout policy is correlated to the number of roundabouts in a state, and states should consider implementing or strengthening their policies if they seek to expand the use of roundabouts in their jurisdiction. In addition, the perception of roundabouts, both by the general public and internal to the state DOTs, also continues to hinder the further implementation of roundabouts, and education should be utilized to minimize these obstacles. Furthermore, states should utilize identified successful implementation procedures, and should be cognizant of reasons for implementation failure, as they pursue the further use of roundabouts by their agency.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 21

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Roundabouts are becoming more widely recognized for their capacity and safety advantages over traffic signals for moderate to high traffic flows. Accordingly, the city of Hamilton considered the feasibility of establishing a roundabout at the intersection of Wilson Street, Meadowbrook Drive and Hamilton Drive in the Town of Ancaster. Wilson Street, a former Provincial secondary highway, connects the village of Ancaster to the City of Brantford. SRM Associates, also branded as Roundabouts Canada, performed a preliminary analysis of the potential operational performance of a modern roundabout for this intersection. The evaluation criteria determining whether a roundabout is feasible at any one intersection required the comparison of traffic capacity performance between a roundabout and a traffic signal and cost benefit comparison of a signalised intersection versus a roundabout including lifecycle cost analysis. An initial study into the feasibility of a roundabout at this intersection included public consultation to establish a roundabout as the preferred intersection control in consideration of alternatives such as traffic signals, all-way stop control and two-way stop control. The study recommended a single lane roundabout with single lane entries and exits. For the covering abstract of this cinference see ITRD number E211395.

Author: Alison Fayre Mills
Publisher:
ISBN:
Category :
Languages : en
Pages : 128

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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.