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KSCE Journal of Civil Engineering

, Volume 23, Issue 2, pp 800–809 | Cite as

Modeling of Unsymmetrical Single-lane Roundabouts based on Stopping Sight Distance

  • Said M. Easa
Transportation Engineering
  • 8 Downloads

Abstract

Evaluation of the adequacy of sight distance at roundabout is usually performed graphically as no quantitative guidelines are available for the lateral clearance needs. This paper presents analytical lateral clearance models to satisfy Stopping Sight Distance (SSD) at unsymmetrical single-lane roundabouts (with different entry and exit radii). The models are developed for three critical locations: approach sight distance, sight distance to exist crosswalk, and circulatory roadway sight distance. Two cases of approach sight distance are presented: sight distance to the crosswalk and sight distance to the yield line. The required lateral clearance at any specified point along the curve can also be determined. Design aids for the required maximum lateral clearance are established for the three locations of sight distance based on accurate SSD formula that accounts for effect of the radial deceleration component of the vehicle. For the circulatory roadway sight distance, infeasible combinations of the circulatory roadway radius and speed are identified based on acceptable driver’s field of peripheral vision. The models and results of this paper, which are applicable to both symmetrical and unsymmetrical roundabouts, should be of interest to highway engineers and designers.

Keywords

unsymmetrical roundabouts stopping sight distance lateral clearance pedestrians crosswalk 

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References

  1. Ali, Z., Easa, S. M., and Hamed, M. (2009). “Stop-controlled intersection sight distance: Minor road on tangent of horizontal curve.” J. Transp. Eng., ASCE, Vol. 135, No. 9, pp. 650–657, DOI: 10.1061/(ASCE)0733-947X(2009)135:9(1650).CrossRefGoogle Scholar
  2. American Association of State Highway and Transportation Officials (2011). A Policy on Geometric Design of Highways and Streets. AASHTO, Washington DC, USA.Google Scholar
  3. Boodlal, L. (2004). Accessible sidewalks and street crossings -An informational guide. Federal Highway Administration, US Department of Transportation, Washington, DC, USAGoogle Scholar
  4. City of Calgary (2010). Cone-of-vision impacts in roundabouts. Final Report, Calgary, AB, Canada, https://doi.org/www.ctep.com/pdf/Bunt%20_Cone%20of%20Vision%20Final%20Report%20.pdf.
  5. Department for Regional Development (2007). Geometric design of roundabouts. Vol. 6, Section 2, Part 3 TD16/07, Belfast, Northern Ireland.Google Scholar
  6. Easa, S. M. (2016). “Pedestrian crossing sight distance: Lateral clearance guidelines for roadways.” Transportation Research Record: Journal of the Transportation Research Board, TRB, Vol. 2588, pp. 32–42, DOI: 10.3141/2588-04.CrossRefGoogle Scholar
  7. Easa, S. M. (2017a). “Lateral clearance needs for stopping sight distance at symmetrical single-lane roundabouts.” Proc., Transportation Research Board Conference, Washington, DC, USA.Google Scholar
  8. Easa, S. M. (2017b). “Design guidelines for symmetrical single-lane roundabouts based on intersection sight distance.” J. Transp. Eng., Part A: Systems, ASCE, Vol. 143, No. 11, DOI: 10.1061/JTEPBS.0000081.Google Scholar
  9. Easa, S. M. and Ali, Z. (2006). “Three-dimensional stop-control intersection sight distance: General Model.” J. of Transportation Research Board, TRB, Vol. 1961, National Research Council, pp. 94–103.CrossRefGoogle Scholar
  10. Easa, S. M., Qu, X., and Dabbour, E. (2017). “Improved pedestrian sight distance needs at railroad-highway grade crossings.” J. Transp. Eng., Part A: Systems, ASCE, Vol. 143, No. 7, DOI: 10.1061/JTEPBS.0000047.Google Scholar
  11. Federal Highway Administration (2006). Intersection safety roundabouts. U.S. Department of Transportation, FHWA, Washington, DC, https://doi.org/safety.fhwa.dot.gov/intersection/innovative/roundabouts/fhwasa10006/#s64.
  12. Government of Queensland (2013). Road planning and design manual. Chapter 14: Roundabouts, Department of Transport and Main Roads, Queensland, Australia.Google Scholar
  13. Harwood, D. W., Mason, J., Brydia, R., Pietrucha, M., and Gittings, G. (1996). Intersection sight distance, NCHRP Report 383. Transportation Research Board, Washington, DC, USAGoogle Scholar
  14. Hussain, A. and Easa, S. M. (2016). “Reliability analysis of left-turn sight distance at signalized intersections.” J. Transp. Eng., Part A: Systems, Vol. 142, No. 3, DOI: 10.1061/(ASCE)TE.1943-5436.0000824.Google Scholar
  15. International Council of Ophthalmology (2006). Vision requirements for driving safety: Visual standards, Report presented at World Ophthalmology Congress, Sao Paulo, Brazil.Google Scholar
  16. Microsoft (2015). Excel 2010 Solver offers more power for optimization, more help for users, https://doi.org/www.prweb.com/releases/excel2010/solver/prweb4148834.htm.
  17. Rodegerdts, L. A., Bansen, J., Tiesler, C., Knudsen, J., Myers, E., Johnson, M., Moule, M., Persaud, B., Lyon, C., Hallmark, S., Isebrands, H., Crown, R., Guichet, B., and O’Brien, A. (2010). Roundabouts: An informational guide. National Cooperative Highway Research Program Report 672, Transportation Research Board, Washington, D.C.Google Scholar
  18. Rodegerdts, L., Blogg, M., Wemple, E., Myers, E., Kyte, M., Dixon, M., List, G., Flannery, A., Troutbeck, R., Brilon, W., Wu, N., Persaud, B., Lyon, C., Harkey, D., and Carter, C. (2007). Roundabouts in the United States, National Cooperative Highway Research Program Report 572, Transportation Research Board, Washington, DC, USA.Google Scholar
  19. Transportation Association of Canada (2016). Manual of uniform traffic control devices for Canada, TAC, Ottawa, ON, Canada.Google Scholar
  20. Washington State Department of Transportation (2016). Roundabouts. Chapter 1320, WSDOT, Olympia, WA, USA.Google Scholar

Copyright information

© Korean Society of Civil Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Dept. of Civil EngineeringRyerson UniversityTorontoCanada

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