The deviation angle for one-lane roundabouts: A general mathematical formulation and application
Abstract Properly designed roundabouts may lead to safety improvements based on both reducing approaching speeds and controlling traffic. Measurements of deflection of vehicle trajectories are commonly used to estimate roundabout speed control. One of these measurements is the deviation angle, which...
Published in: | Journal of Traffic and Transportation Engineering (English Edition) |
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ftopenaccessrep:oai:zenodo.org:86235 2023-10-25T01:43:14+02:00 The deviation angle for one-lane roundabouts: A general mathematical formulation and application Nicola Berloco Paolo Intini Pasquale Colonna 2022-02-01 https://www.openaccessrepository.it/record/86235 https://doi.org/10.1016/j.jtte.2020.10.006 eng eng url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/86235 doi:10.1016/j.jtte.2020.10.006 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-nd/4.0/ Transport Research Transportation Civil and Structural Engineering info:eu-repo/semantics/article publication-article 2022 ftopenaccessrep https://doi.org/10.1016/j.jtte.2020.10.006 2023-09-26T22:21:27Z Abstract Properly designed roundabouts may lead to safety improvements based on both reducing approaching speeds and controlling traffic. Measurements of deflection of vehicle trajectories are commonly used to estimate roundabout speed control. One of these measurements is the deviation angle, which is mentioned in both the Italian and Swiss road standards and, in specific conditions, can be more effective than other methods. This article presents a general mathematical formulation for linking several geometric parameters with the deviation angle in different rural and urban one-lane roundabout configurations, which is currently missing in the literature. For urban roundabouts, refuge islands for pedestrians and cyclists were considered. Based on the proposed formulation, a sensitivity analysis of the influential geometric parameters was conducted. Results suggest that an insufficient deflection of trajectories (deviation angle less than 45°) is always present for roundabouts with inscribed circle diameter less than 25 m; for urban roundabouts with refuge islands for pedestrians and cyclists having inscribed circle diameter less than 34 m and orthogonal legs; and for roundabouts with angles between opposite legs smaller than 140°. The main parameters which are responsible for a decrease in the deviation angle are: a decrease in the inscribed circle diameter; a decrease in the angle between opposite legs; and an increase in the width of the circulatory lane. Some optimized procedures for roundabout design, the generalized application of the deviation angle method and alternative speed control measures in cases of small deviation angles are discussed. Article in Journal/Newspaper Refuge Islands Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository Refuge Islands ENVELOPE(-67.166,-67.166,-68.350,-68.350) Journal of Traffic and Transportation Engineering (English Edition) 9 1 44 58 |
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Open Polar |
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Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository |
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ftopenaccessrep |
language |
English |
topic |
Transport Research Transportation Civil and Structural Engineering |
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Transport Research Transportation Civil and Structural Engineering Nicola Berloco Paolo Intini Pasquale Colonna The deviation angle for one-lane roundabouts: A general mathematical formulation and application |
topic_facet |
Transport Research Transportation Civil and Structural Engineering |
description |
Abstract Properly designed roundabouts may lead to safety improvements based on both reducing approaching speeds and controlling traffic. Measurements of deflection of vehicle trajectories are commonly used to estimate roundabout speed control. One of these measurements is the deviation angle, which is mentioned in both the Italian and Swiss road standards and, in specific conditions, can be more effective than other methods. This article presents a general mathematical formulation for linking several geometric parameters with the deviation angle in different rural and urban one-lane roundabout configurations, which is currently missing in the literature. For urban roundabouts, refuge islands for pedestrians and cyclists were considered. Based on the proposed formulation, a sensitivity analysis of the influential geometric parameters was conducted. Results suggest that an insufficient deflection of trajectories (deviation angle less than 45°) is always present for roundabouts with inscribed circle diameter less than 25 m; for urban roundabouts with refuge islands for pedestrians and cyclists having inscribed circle diameter less than 34 m and orthogonal legs; and for roundabouts with angles between opposite legs smaller than 140°. The main parameters which are responsible for a decrease in the deviation angle are: a decrease in the inscribed circle diameter; a decrease in the angle between opposite legs; and an increase in the width of the circulatory lane. Some optimized procedures for roundabout design, the generalized application of the deviation angle method and alternative speed control measures in cases of small deviation angles are discussed. |
format |
Article in Journal/Newspaper |
author |
Nicola Berloco Paolo Intini Pasquale Colonna |
author_facet |
Nicola Berloco Paolo Intini Pasquale Colonna |
author_sort |
Nicola Berloco |
title |
The deviation angle for one-lane roundabouts: A general mathematical formulation and application |
title_short |
The deviation angle for one-lane roundabouts: A general mathematical formulation and application |
title_full |
The deviation angle for one-lane roundabouts: A general mathematical formulation and application |
title_fullStr |
The deviation angle for one-lane roundabouts: A general mathematical formulation and application |
title_full_unstemmed |
The deviation angle for one-lane roundabouts: A general mathematical formulation and application |
title_sort |
deviation angle for one-lane roundabouts: a general mathematical formulation and application |
publishDate |
2022 |
url |
https://www.openaccessrepository.it/record/86235 https://doi.org/10.1016/j.jtte.2020.10.006 |
long_lat |
ENVELOPE(-67.166,-67.166,-68.350,-68.350) |
geographic |
Refuge Islands |
geographic_facet |
Refuge Islands |
genre |
Refuge Islands |
genre_facet |
Refuge Islands |
op_relation |
url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/86235 doi:10.1016/j.jtte.2020.10.006 |
op_rights |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.1016/j.jtte.2020.10.006 |
container_title |
Journal of Traffic and Transportation Engineering (English Edition) |
container_volume |
9 |
container_issue |
1 |
container_start_page |
44 |
op_container_end_page |
58 |
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1780740043797692416 |