New Type of Roundabout: Dual One-Lane Roundabouts on Two Levels with Right-Hand Turning Bypasses – ’’Target Roundabout’’

  • Tomaž Tollazzi University of Maribor, Faculty for Civil Engineering
  • Goran Jovanović Appia d.o.o. LeskoÅ¡kova 9e SI-1000 Ljubljana Slovenija
  • Marko Renčelj University of Maribor, Faculty for Civil Engineering
Keywords: roundabouts, alternative types of roundabouts, turbo roundabout, target roundabout


The problems of low level traffic safety on multi-lane roundabouts have been resolved in various ways in different countries, usually by using alternative types of roundabouts that reduce the number of conflict points. Alternative types of roundabouts typically differ from 'normal' or 'standard' roundabouts in one or more design elements, as their implementation purposes could also be specific. Today, several different types of roundabouts are already in use ('mini', 'double mini', 'dumb-bell', those 'with joint splitter islands' ('dog-bone'), those 'with a spiralling circular carriageway' ('turbo'), those 'with depressed lanes for right-hand turners' ('flower') etc.). This paper introduces a new type of roundabout, dual one-lane roundabouts on two levels with right-hand turning bypasses, namely the 'target roundabout'. This paper describes and analyses their design, traffic safety, and capacity characteristics, compared with the standard two–lane roundabouts.


Brown, M.: The Design of Roundabouts. London: HMSO. 270 p. ISBN 0115517413, 1995.

Mauro, R.; Branco, F.: Comparative Analysis of Compact Multilane Roundabouts and Turbo-Roundabouts, Journal of Transportation Engineering, Vol. 136, No. 4: 316-322, April 2010. DOI: 10.1061/(ASCE)TE.1943-5436.0000106

Engelsman, J.C.; Uken, M.: Turbo roundabouts as an alternative to two lane roundabouts, in Proc. of the 26th Southern African Transport Conference (SATC 2007). Ed. by Underwood, G. July 9-12, 2007, Pretoria, South Africa. Produced by: Document Transformation Technologies cc. ISBN Number: 1-920-01702-X

Fortuijn, L.G.H.: Turbo Roundabouts: Design Principles and Safety Performance, Journal of the Transportation Research Board: 16 – 24. 2009, DOI: 10.3141/2096-03

Žilionienė, D.; Oginskas, R.; Petkevičius, K.: Research, analysis and evaluation of roundabouts constructed in Lithuania, The Baltic Journal of Road and Bridge Engineering 5(4), 2010: 240-245. DOI: 10.3846/bjrbe.2010.32.

Tollazzi, T.; Renčelj, M.; Turnšek, S.: New type of roundabout: roundabout with ''depressed'' lanes for right turning – ''flower roundabout'', Promet – Traffic & Transportation, 2011, Vol. 23, No. 5: 353 – 358. DOI: 10.7307/ptt.v23i5.153

Mauro, R.; Cattani, M.: Functional and Economic Evaluations for Choosing Road Intersection Layout, Promet – Traffic & Transportation, 2012, Vol. 24, No. 5: 441 – 448. DOI:

Tollazzi, T.; Renčelj, M.; Turnšek, S.; Jovanović, G.: Krožno križišče s pritisnjenimi pasovi za desno zavijanje [Tollazzi, T.; Renčelj, M.; Turnšek, S.; Jovanović, G. Roundabout with ''depressed'' lanes for right turning – ''flower roundabout''] Urad Republike Slovenije za intelektualno lastnino, SI 23266 (A), 2011-07-29 [Patent No. 23266 of the Republic of Slovenia, published 29.07.2011]

Fortuijn, L.G.H.; Carton, P.J.: Turbo Circuits: A Well-tried Concept in a New Guise, Board of Economy and Transport, Province of South Holland, 2000, http://

How to Cite
Tollazzi T, Jovanović G, Renčelj M. New Type of Roundabout: Dual One-Lane Roundabouts on Two Levels with Right-Hand Turning Bypasses – ’’Target Roundabout’’. Promet [Internet]. 2013Oct.27 [cited 2024Jul.22];25(5):475-81. Available from: