Intersection Sight Distance Requirements for Basic Turbo Roundabouts
Publication: Journal of Transportation Engineering, Part A: Systems
Volume 149, Issue 2
Abstract
Turbo roundabouts, emerging as a solution to conventional multilane roundabouts’ safety and operations concerns, are prevalent in Europe and are still new to North America. However, few studies and guidelines on intersection sight distance (ISD) requirements exist. This paper focuses on the basic turbo roundabouts, examines the circulatory roadway and approach design features, and develops ISD models with North American practices. The ISD requirements were identified for the vehicle approaching and entering the roundabout, which conflicts with the circulating vehicle in the circulatory roadways, and the entering vehicle at the upstream entry approach. Analytical models were developed to identify the required lateral clearance at the central island and clear sight triangles at the roundabout quadrants to satisfy the required ISD. The analyses were completed for four typical sizes of basic turbo roundabouts per Dutch design criteria. The design guidelines are provided for the required lateral clearance at the central island and the required clear sight triangles at the roundabout quadrants. They would be beneficial in establishing landscaping restrictions and determining the roadway right of way and property impacts at the intersections during the roadway planning stage.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The authors are grateful to the anonymous reviewers for their thorough and most helpful comments. This research was financially supported by a Discovery Grant from the Natural Sciences and Engineering Council of Canada.
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© 2022 American Society of Civil Engineers.
History
Received: Dec 30, 2021
Accepted: Sep 23, 2022
Published online: Nov 24, 2022
Published in print: Feb 1, 2023
Discussion open until: Apr 24, 2023
ASCE Technical Topics:
- Business management
- Design (by type)
- Engineering fundamentals
- Geology
- Geotechnical engineering
- Highway and road design
- Highway and road management
- Highway transportation
- Highways and roads
- Infrastructure
- Intersections
- Islands
- Practice and Profession
- Public administration
- Public health and safety
- River engineering
- Rivers and streams
- Safety
- Sight distances
- Transportation engineering
- Vehicles
- Water and water resources
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