Signal timing optimization model based on dual-ring phase scheme for roundabout

Abstract

A signal optimization model for roundabout was proposed based on dual-ring scheme and two stop lines for left turns control concept were used to eliminate the conflict points and weaving sections at a roundabout. A cycle length minimization problem was considered to generate optimal signal timings for roundabout, and a set of constraints to ensure feasibility and safety of the resulting optimal signal settings were proposed. Extensive experimental analyses in comparison with signalized intersection reveal that the proposed model is quite promising for application in design of roundabout signals, and the minimum cycle length can decrease from 186 s to 79 s while the capacity increases from 8 682 pcu/h to 9 011 pcu/h under high demand scenario. Sensitivity analysis with respect to the system performance show that the lane assignment plan, number of circulatory lanes and left turn ratio are three critical factors which have dominate impacts on performance of signalized roundabout

Keywords

signalized roundabout / dual-ring phase / single timing optimization / left-turn movement

References

[1] Transportation Research Board of the National Academies. Delivery draft chapter 21: Roundabouts. Highway Capacity Manual [M]. Washington D. C.: Transportation Research Board Press, 2010.

[2] HallworthM. S.. Signaling roundabouts [J]. Traffic Engineering and Control, 1992, 33(6): 46-51

[3] INSURANCE INSTITUTE FOR HIGHWAY SAFETY. Q&As: Roundabouts. Insurance Institute 40 for Highway Safety, Highway Loss Data Institute [EB/OL]. [2010-4-30]. http://www.iihs.org/research/qanda/roundabouts.html.

[4] RodegerdtsL., BloggM., WempieE., et al. Roundabouts in the United States [R], 2007Washington D. CNCHRP Report 572, Transportation Research Board of the National Academies

[5] Al-OmariB. H., Al-MasaeidH. R., Al-ShawabkahY. S.. Development of a delay model for roundabouts in Jordan [J]. Transport Eng, 2004, 130(1): 76-82

[6] Al-MadaniH. M. N.. Dynamic vehicular delay comparison between a police-controlled roundabout and a traffic signal [J]. Transportation Research A, 2003, 37(8): 681-688

[7] SACCOMANNO S F, CUNTO F, GUISEPPE G, VITALE A. Comparing safety at signalized intersections and roundabouts using simulated rear end conflicts[C]// Transportation Research Board Annual Meeting. Washington D. C 2008: 90–95

[8] MARILYN V, RUEY L C, CARLOS D. Operations of a modern roundabout with unbalanced approach volume[C]// Transportation Research Board Annual Meeting Washington D C, 2011: 234–243

[9] AKÇELIK R. A roundabout case study comparing capacity estimates from alternative analytical models[C]// Urban Street Symposium, Anaheim, California, USA, 2003: 1–20.

[10] DIXIT, V V, RADWAN E. Roundabout capacity: A New Perspective[C]// Transportation Research Board Annual Meeting. Washington D C, 2008: 08–1399.

[11] YangX., LiX., XueK.. A new traffic-signal control for modern roundabouts: Method and application [J]. IEEE Transactions on Intelligent Transportation Systems, 2004, 5(4): 282-287