Statistical Analysis of Two-lane Roundabout Data for Traffic Control Decision-Making in an Urban Area

Document Type : Research Paper


1 Department of Civil Engineering, Yazd University, Yazd, Iran

2 MSc. Grad., Department of Civil Engineering, Yazd University, Yazd, Iran.

3 Associate Professor, Faculty of Civil Engineering, UITM, Malaysia


Researches using existing statistics and data collected from the area of study help officials at decision-making, to improve the region's problems, like the problem of the high rate of accidents in the region, despite the low volume of daily service. The uses of roundabouts in many parts of the world have many advantages over intersections, amongst them are increased safety and capacity and reduced cost. To improve roundabout function, roundabout traffic control and vehicle safety, informed decision-making from studies carried out is required. Roundabout design for Capacity and safety are inseparable components, due to the conditions of roundabout geometry, traffic sign, pavement conditions and patterns of driver’s behavior change. The aim of this study was to evaluate the importance and influence of these parameters on the behavior of drivers. In this research, the effect of Pavement Condition Index (PCI), Contrast of roundabout lane lines color and volume-to-capacity ratio on the value of obeying the rules of the road for drivers (using turn signals and avoiding unnecessary lane change at roundabout) were evaluated. Data was gathered through field research of seven roundabouts in the city of Yazd, Iran. Statistical methodologies (t-test method and bivariate regression) and the CART model were used for data analysis. Results show when Pavement Condition Index (PCI) improves, unnecessary lane changes by drivers at the roundabout decrease. Similarly, the use of turn signal increases with an increase in the volume-to-capacity ratio, so in the roundabouts with a higher volume-to-capacity ratio of 0.58, 47.5% of drivers use turn signals, while with a less volume-to-capacity ratio of 0.58, the rate of using turn signal will be less than this amount (11.7%).This suggests the need for policy-making at roundabout with low volume-to-capacity ratio, to encourage the use of turn signals by drivers. The results of this research can help city managers and traffic police to prioritize traffic control and reform municipal roundabouts.


- Almejalli, K., Dahal, K. and Hossain, A. (2006) "Road traffic decision support system", SKIMA, Proceedings of the International conference on Software Knowledge Information Management and Applications, 2006, pp. 85-89.
-Al-Atawi, A.M. (2014)" Characteristics of red light running violations in urban areas in Tabuk, Kingdom of Saudi Arabia", IATSS Research 37, 2014, pp.119–123. doi:10.1016/j.iatssr.2013.08.001
-ASTM D6433-11 (2011) "Standard practice for roads and parking lots pavement condition index surveys", ASTM International, West Conshohocken, PA .
-Bastos Silva, A.  Santos, S. L., Vasconcelos, Á., Seco, J. and Pedro, Silva (2014)  "driver behavior characterization in roundabout crossings", Transportation Research Procedia, Vol. 3 ,pp.80-89. Doi:10.1016/j.trpro.2014.10.093
-Beshah, T., Ejigu, D., Abraham, A.,  Snasel, V. and Kromer, P. (2013) " Mining pattern from road  accident data: role of road user's behavior and implications for improving road safety", International journal of tomography and simulation, vol. 22, No. 1,2013, pp. 73–86
-Cao, Y. (2004)" A driving simulation based study on the effects of road marking luminance contrast on driving safety", Institute of Transportation Engineers (ITE) , District 1 Annual Meeting, Burlington, Vermont
-Chan, C.Y., Huang, B.,   Yan, X. and Richards, S. (2008) "Effects of asphalt pavement conditions on traffic accidents in Tennessee utilizing pavement management system (PMS)", Southeastern Transportation, Center University of Tennessee, Knoxville. Source:
-Chang, L.Y. (2013)" Analysis of effects of manhole covers on motorcycle driver maneuvers: a non-parametric classification tree approach", Traffic Injury Prevention, Vol. 15, No.2, pp.206–212. DOI:10.1080/15389588.2013.792110
- Colour Contrast Checker Software (2015) source:
-Diah, J. Rahman  MYA, , Adnan, M. A. and. Ling, K. H. (2011)" Modeling the relationship between geometric design and weaving section flow process of conventional roundabouts", Journal Of Transportation Engineering , ASCE / December 2011, pp.980-986
-Dell’Acqua, G.  De Luca, M. and Mauro, R. (2011) "Road safety knowledge-based decision support system", Procedia Social and Behavioral Sciences, No. 20, pp. 973–983, Doi:10.1016/j.sbspro.2011.08.106
 -Fanga, Y.  and Guo, Z. (2013) "Decision-making model of roadside safety improvement on two lane highway",  Procedia - Social and Behavioral Sciences 96 , pp.390 – 397. Doi: 10.1016/j.sbspro.2013.08.046
-Federal Highway Administration, FHWA (2010)" Roundabouts: technical summary", FHWA-SA-10-006. U.S. Department of Transportation Federal Highway Administration.
-Guan, H., Li, J., Yu, Y., Wang, C.,  Chapman, M. and Yang, B. (2014) "Using mobile laser scanning data for automated extraction of road markings", ISPRS Journal of Photogrammetry and Remote Sensing, Vol. 87,  pp.93–107.
-Kusuma, A. and Koutsopoulos, H. N. (2011) "Critical gap analysis of dual lane roundabouts", Procedia Social and Behavioral Sciences, No. 16, pp. 709–717. Doi:10.1016/j.sbspro.2011.04.490
-Li, Y., Liu, C. and Ding, L. (2013) "Impact of pavement conditions on crash severity", accident analysis and prevention, Vol. 59, pp. 399– 406. Doi: 10.1016/j.aap.2013.06.028
-Mcknight, A. S.  Mcknight, A.J. and  Tippetts, A. S. (1998) "The effect of lane line width and contrast upon lanekeeping",  Accid. Anal. and  Prev., Vol. 30, No. 5 , pp. 617–624, Doi:10.1016/S0001-4575(98)00015-3
-Manual, Highway Capacity. (2000)"HCM 2000." Washington, DC: Transportation Research Board.
-Mills, A.  Duthie, J.,  Machemehl, R.,  Ferguson, E.,  Waller T. and Sun, D. (2011) "Texas roundabout guidelines: final report", Center for Transportation Research at The University of Texas at Austin, p..120.
-Montella,A. Turner,S., Chiaradonna, S. ,Aldridge, D.,(2012) "proposals for improvement of the italian roundabout geometric design standard", Procedia - Social and Behavioral Sciences, No. 53 ,2012, 189 – 202, Doi:10.1016/j.sbspro.2012.09.872
-NCHRP report 672, Roundabouts: An Informational Guide, (2010) Washington, DC.
Pande, A.  Abdel-Aty M.(2009,"market basket analysis of crash data from large jurisdictions and its potential as a decision support tool ",Safety Science 47, 145–154, Doi:10.1016/j.ssci.2007.12.001
-Park, E.S.  Carlson, P.J.  Porter, R.J. Andersen, C.K. (2012) "safety effects of wider edge lines on rural, two-lane highways", Accident Analysis and Prevention 48, pp.317–325, doi:10.1016/j.aap.2012.01.028
-Shahi, J. (2010) “Traffic engineering”, Eleventh Edition, University Publication Center,Tehran,p.236.
-Shahin, M.Y. (2002) "Pavement management for airports, roads and parking lots", United States of America: New York, p. 572.
-Sullivan, J. M., Bao, S.,  Goudy, R. and  Konet, H. (2015) "Characteristics of turn signal use at intersections in baseline naturalistic driving", Accident Analysis & Prevention, Vol. 74, pp. 1–7.
-Robinson, B. W., Rodegerdts, L., Scarborough, W., Kittelson, W., Troutbeck, R., Brilon, W. and  Flannery, A. (2000) "Roundabouts: an informational guide" (No. FHWA-RD-00-067)
-Sullivan, J. M.  and Flannagan, M. J. (2012) "The influence of rear turn-signal characteristics on crash risk", Journal of Safety Research, Vol. 43, Issue 1, pp. 59–65.
-U.S. Department of Transportation, Federal Highway Administration, MUTCD (2009) “Manual on Uniform Traffic Control Devices for streets and highways”, FHA.
-World Health Organization (2010) "Data systems: a road safety manual fordecision-makers andpractitioners" , WHO Press,pp164. Source: