{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T09:16:55Z","timestamp":1777886215807,"version":"3.51.4"},"reference-count":34,"publisher":"SAGE Publications","issue":"1","license":[{"start":{"date-parts":[[2014,1,1]],"date-time":"2014-01-01T00:00:00Z","timestamp":1388534400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Transportation Research Record: Journal of the Transportation Research Board"],"published-print":{"date-parts":[[2014,1]]},"abstract":"<jats:p>A \u201cturboroundabout\u201d is a variation of the conventional multilane roundabout in which spiral road markings and raised lane dividers force drivers to follow a specific path according to their intended destination. This geometry eliminates weaving and cut-in conflicts by guiding drivers continuously from entry to exit. Turboroundabouts were conceived with the main aim of improving safety, but their practical benefits are relatively unknown. Likewise, the few existing studies on turboroundabouts do not allow definitive conclusions to be drawn about the delay and emissions performance characteristics of turboroundabouts; further research is needed. This research focused on the use of appropriate modeling methodologies to understand the effects of turboroundabouts on capacity, safety, and emissions in comparison with the effects of conventional single-lane and double-lane roundabouts. The results indicate that turboroundabouts have capacity levels comparable to those of two-lane roundabouts but are less robust concerning the directional split of the entry traffic; turboroundabouts lead to fewer traffic conflicts, but the traffic conflicts that do occur are more severe. The results also show that the implementation of turboroundabouts provides no advantages for emissions when the main concerns are carbon dioxide and oxides of nitrogen.<\/jats:p>","DOI":"10.3141\/2402-04","type":"journal-article","created":{"date-parts":[[2014,7,7]],"date-time":"2014-07-07T21:57:45Z","timestamp":1404770265000},"page":"28-37","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":70,"title":["Turboroundabouts"],"prefix":"10.1177","volume":"2402","author":[{"given":"Lu\u00eds","family":"Vasconcelos","sequence":"first","affiliation":[{"name":"Department of Civil Engineering, Polytechnic Institute of Viseu, Campus Polit\u00e9cnico de Repeses, 3504-510 Viseu, Portugal."}]},{"given":"Ana B.","family":"Silva","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering, University of Coimbra, Rua Lu\u00eds Reis Santos-P\u00f3lo II, 3030-788 Coimbra, Portugal."}]},{"given":"\u00c1lvaro M.","family":"Seco","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering, University of Coimbra, Rua Lu\u00eds Reis Santos-P\u00f3lo II, 3030-788 Coimbra, Portugal."}]},{"given":"Paulo","family":"Fernandes","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering\u2013Center for Mechanical Technology and Automation, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal."}]},{"given":"Margarida C.","family":"Coelho","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering\u2013Center for Mechanical Technology and Automation, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal."}]}],"member":"179","published-online":{"date-parts":[[2014,1,1]]},"reference":[{"key":"bibr1-2402-04","doi-asserted-by":"publisher","DOI":"10.3141\/2096-03"},{"key":"bibr2-2402-04","unstructured":"BrilonW. Studies on Roundabouts in Germany: Lessons Learned. Presented at the 3rd International Conference on Roundabouts, Carmel, Ind. 2011."},{"key":"bibr3-2402-04","unstructured":"TollazziT., RenceljM., and TurnsekS. Slovenian Experiences with Alternative Types of Roundabouts\u2014\u201cTurbo\u201d and \u201cFlower\u201d Roundabouts. Presented at the 8th International Conference on Environmental Engineering, Vilnius, Lithuania, 2011."},{"key":"bibr4-2402-04","unstructured":"TruebloodM. Retrofitting Closely Spaced Intersections Using the Peanut Turboroundabout Concept. Presented at the 3rd International Conference on Roundabouts, Carmel, Ind. 2011."},{"key":"bibr5-2402-04","unstructured":"YpermanI., and ImmersL. H. Capacity of a Turbo-Roundabout Determined by Micro-Simulation. Presented at the 10th World Congress on ITS, Madrid, Spain, 2003."},{"key":"bibr6-2402-04","unstructured":"EngelsmanJ. C., and UkenM. Turboroundabouts as an Alternative to Two Lane Roundabouts. 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