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Safety Effectiveness of Converting Conventional Intersections to Roundabouts: Case Study in the City of Niš
Milan Vujanić, Milan Savićević, Boris Antić, Dalibor Pešić
Keywords:traffic safety effectiveness, roundabouts, Empirical Bayes method,


Intersections present a big safety problem in traffic since there has been an increased risk of crashes because of conflicts in the flows intersecting. A great number of studies done in the world show that roundabouts are safer than conventional intersections since it has been recorded that after the conversion to roundabouts the number of crashes has been decreasing. The research on applying Empirical Bayes (EB) method has been conducted by using 15 two-lane intersections in the city of Niš (Serbia), which have been converted into large compact two-lane roundabouts during the period of 2005-2013. The results show that the conversion of conventional intersections into roundabouts has positive effect on reducing the number of crashes. For all intersections, the reduction of crashes is estimated at around 76% for all crashes, i.e. 80% for the crashes with injuries. For different groups of intersections the effects are determined separately.


Gross F, Lyon C, Persaud B, Srinivasan R. Safety effectiveness of converting signalized intersections to roundabouts. Accident Analysis and Prevention. 2013;50:234-241.

raffic Safety Agency. Statistical traffic safety report in the Republic of Serbia in 2012 [in Serbian]. Belgrade: Traffic Safety Agency; 2013.

Thai Van M, Balmefrezol P. Design of roundabouts in France. Transportation Research Record. 2013;1737:92-97.

Rodegerdts L, Bansen J, Tiesler C, Knudsen J, Myers E. Roundabouts: An informational gude. Report 672 - Second Edition. Transportation Research Board – National Cooperative Highway Research Program. Washington DC, USA; 2010.

Pellecuer L, St-Jaques M. Last advance about roundabouts. Canadian Journal of Civil Engineering. 2008;35:542-553.

Sacchi E, Bassani M, Persaud B. Comparison of Safety Performance Models for Urban Roundabouts in Italy and Other Countries. Transportation Research Record. 2011;2265:253-259.

Sangyoup K, Jaisung C. Safety Analysis of Roundabout Designs based on Geometric and Speed Characterisitcs, KSCE Journal of Civil Engineering. 2013;17(6):1446-1454.

Pilko H, Brčić D, Šubić N. Study of vehicle speed in the design of roundabouts. Građevinar. 2014;66(5):407-416.

Schoon C, Van Minnen J. Accidents at roundabouts II: Second investigation into the safety of roundabouts especially for cyclists and moped riders [in Dutch]. Stichting Wetenschappelijk Onderzoek Verkeersveiligheid (SWOV), rapport R-93-16. Leidschendam; 1993.

Institute of Transportation Engineers–ITE. Traffic Safety Toolbox: A Primer on Traffic Safety. Washington DC, USA: Institute of Transportation Engineers; 1999.

Hyden C, Varhelyi A. The effects on safety time consumption and environment of large scale use of roundabouts in an urban area: a case study. Accident Analysis and Prevention. 2000;32(1):11-23.

Persaud B, Retting R, Garder P, Lord D. Safety effects of roundabout conversions in the United States: empirical Bayes observational before-and-after study. Transportation Research Record. 2001;1751:1-8.

Elvik R. Effects on road safety of converting intersections to roundabouts: review of evidence from Non-U.S. studies. Transportation Research Record. 2003;1847:1-10.

De Brabander B, Vereeck L. Safety effects of roundabouts in Flanders: Signal type, speed limits and vulnerable road users. Accident Analysis and Prevention. 2007;39(3):591-599.

Daniels S, Brijs T, Nuyts E, Wets G. Explaining variation in safety performance of roundabouts. Accident Analysis and Prevention. 2010;42(2):393-402.

Hels T, Orozova-Bekkevold I. The effect of roundabout design features on cyclist accident rate. Accident Analysis and Prevention. 2007;39(2):300-307.

Stone J R, Chae K, Pillalamarri S. The effects of roundabouts on pedestrian safety. Southeastern Transportation Center, working paper. Tenessee, USA; 2002.

Candappa N, Stephan K, Corben B. Raised crosswalks on entrance to the roundabout-a case study on effectiveness of treatment on pedestrian safety and convenience. Traffic Injury Prevention. 2014;15(6):631-639.

Senica G, Milosevic М. Modern roundabouts – planning process. Project Institute, Belgrade; 2002.

Brüde U, Larsson J. What roundabout design provides the highest possible safety? Nordic Road Transport Res. 2000;12(2):17-21.

Hauer E. Observational Before–After Studies in Road Safety: Estimating the Effect of Highway and Traffic Engineering Measures on Road Safety. Pergamon Press, Oxford, UK; 1997.

Bonneson J, Mc Coy P. Estimation of safety at twoway STOP-controlled intersections on rural highways. Transportation Research Record. 1993;1401:83-89.

Vogt A, Bared J. Accident models for two lane rural segments and intersections. Transportation Research Record. 1998;1635:18-29.

Hauer E, Harwood D W, Council F M, Griffith M S. Estimating Safety by the Empirical Bayes Method. Transportation Research Record. 2002;1784:126-131.

Zhang Y, Ye Z, Lord D. Estimating the Dispersion Parameter of the Negative Binomial Distribution for Analyzing Crash Data Using a Bootstraped Maximum Likelihood Method. Transportation Research Record. 2007;2019:15-21.

Vujanić M, Antić B, Pešić D, Savićević M. Application of objective methods for black spot identification and classification. XIII International Conference Road Safety in Local Communities; 2013 April 18-20; Divčibare, Serbia; 2013.

Geurts K, Thomas I, Wets G. Understanding spatial concentrations of road accidents using frequent item sets. Accident Analysis and Prevention. 2005;37(4):787-799.

Simodines T, Welch T, Kuntemeyer M. Effects of Reducing Conflict Points on Reducing Accidents. Third National Access Management Conference. Fort Lauderdale, Florida, USA; 2001.

Bared J.G., Kennedy K. Safety Impacts of Modern Roundabouts, Chapter 28, the Traffic Safety Toolbox: A Primer on Traffic Safety. Institute of Transportation Engineers; 2000.

Vujanić M, Lipovac K, Jovanović D, Pešić D, Antić B. “Bottom-up” and “top-down” approach for defining road safety strategy – case study: City of Belgrade. International Journal for Traffic and Transport Engineering. 2013;3(2):185-203.

Institute of Transportation Engineers - ITE. Before-and-after study. Technical brief. Washington DC, USA: Institute of Transportation Engineers; 2009.

Mun S, Lee Y. The Comparison Study on Observational Before-After Studies: Case Study on Safety Evaluation on Highways. Journal of Korean Society of Transportation. 2013;31(6):67-89.

Brilon, W. Studies on Roundabouts in Germany: Lessons Learned, 3rd International TRB-roundabout Conference; 2011 May 18-20; Carmel, Indiana; 2011.

Copyright (c) 2023 Milan Vujanić, Milan Savićević, Boris Antić, Dalibor Pešić

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