Design Guidelines for Symmetrical Single-Lane Roundabouts Based on Intersection Sight Distance
Publication: Journal of Transportation Engineering, Part A: Systems
Volume 143, Issue 10
Abstract
Checking roundabout sight distance is currently performed graphically. This paper develops analytical models for lateral clearance at symmetrical single-lane roundabouts based on intersection sight distance (ISD) and establishes related geometric design guidelines. The models are developed for two cases: an approach vehicle ahead of the yield line and before the crosswalk (Case 1), and a stationary vehicle at the yield line (Case 2). Sight distances to the respective conflicting-circulating and entering vehicles are analyzed. The maximum lateral clearance is formulated for each case using mathematical optimization. The results show that both cases of the approach and stationary vehicles are critical and therefore should be included in the ISD analysis at roundabouts. Using the developed models, design guidelines are established for the radius of the central island, entry-curve lateral clearance, exit crosswalk location, and driver’s field of peripheral vision.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The author is grateful to two anonymous reviewers for their thorough and most helpful comments. This research is financially supported by a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada (NSERC).
References
AASHTO. (2011). A policy on geometric design of highway and streets, Washington, DC.
Ali, Z., Easa, S. M., and Hamed, M. (2009). “Stop-controlled intersection sight distance: Minor road on tangent of horizontal curve.” J. Transp. Eng., 650–657.
City of Calgary. (2010). “Cone-of-vision impacts in roundabouts.” ⟨http://ctep.ca/wp-content/uploads/2016/11/Bunt-_Cone-of-Vision-Final-Report-.pdf⟩ (Jul. 8, 2017).
City of Colorado Springs. (2005). “Roundabout design standards.” ⟨http://www.springsgov.com/Files/RoundaboutDesignStandards.pdf⟩ (Jul. 8, 2017).
DRDNI (Department for Regional Development, Northern Ireland). (2007). Geometric design of roundabouts, Vol. 6, Belfast, U.K.
Easa, S. M. (2016). “Pedestrian crossing sight distance: Lateral clearance guidelines for roadways.”, 2588, 32–42.
Easa, S. M. (2017). “Lateral clearance needs for stopping sight distance at symmetrical single-lane roundabouts.” Proc., Annual Conf. of Transportation Research Board, Transportation Research Board, Washington, DC.
Easa, S. M., and Ali, Z. (2006). “Three-dimensional stop-control intersection sight distance: General model.”, 1961, 94–103.
Easa, S. M., Dabbour, E., and Ali, Z. (2004). “Three-dimensional model for stop-control intersection sight distance.” J. Transp. Eng., 261–270.
Easa, S. M., Qu, B., and Dabbour, E. (2017). “Improved pedestrian sight distance needs at railroad-highway grade crossings.” J. Transp. Eng. Part A Syst., 143(7), 04017027.
FHWA (Federal Highway Administration). (2006). Intersection safety roundabouts, U.S. Dept. of Transportation, Washington, DC.
GQ (Government of Queensland). (2013). “Roundabouts.” Chapter 14, Road planning and design manual, Dept. of Transport and Main Roads, Brisbane, QLD, Australia.
Harwood, D. W., Mason, J., Brydia, R., Pietrucha, M., and Gittings, G. (1996). “Intersection sight distance.”, Transportation Research Board, Washington, DC.
ICO (International Council of Ophthalmology). (2006). “Vision requirements for driving safety: Visual standards.” Proc., World Ophthalmology Congress, San Francisco.
Joshua, S., and Saka, A. (1992). “Mitigation of sight distance problem for unprotected left-turning traffic at intersections.”, 1356, 73–79.
McCoy, P. T., Pesti, G., Byrd, P. S., and Singh, V. A. (2001). “Guidelines for opposing left-turn lane-line widths.”, 1751, 26–34.
MDOT (Maryland Department of Transportation). (1995). Roundabout design guidelines, State Highway Administration, Baltimore.
Rodegerdts, L. A., et al. (2010). “Roundabouts: An informational guide.”, Transportation Research Board, Washington, DC.
Solver [Computer software]. Excel Master Series, Incline Village, NV.
Steinkuller, P. G. (2010). “Legal vision requirements for drivers in the United States.” AMA J. Ethics, 12(12), 938–940.
TAC (Transportation Association of Canada). (2017). Geometric design guide for Canadian roads, Ottawa.
Tian, Z. Z., et al. (2007). Roundabout geometric design guidance, California Dept. of Transportation, Sacramento, CA.
WDOT (Wisconsin Department of Transportation). (2016). “Roundabouts.” Chapter 11, Facilities development manual, Madison, WI.
WSDOT (Washington State Department of Transportation). (2016). “Roundabouts.” Chapter 1320, WSDOT Design Manual M 22.01, Olympia, WA.
Information & Authors
Information
Published In
Journal of Transportation Engineering, Part A: Systems
Volume 143 • Issue 10 • October 2017
Copyright
© 2017 American Society of Civil Engineers.
History
Received: Feb 10, 2017
Accepted: May 3, 2017
Published online: Aug 5, 2017
Published in print: Oct 1, 2017
Discussion open until: Jan 5, 2018
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.