Determinants of crash numbers and constellations at turbo roundabouts in Germany
DOI:
https://doi.org/10.55329/mpaf3385Keywords:
crash constellation, crash prediction model, crash type, physical dividers, turbo roundaboutAbstract
Turbo roundabouts are a relatively new design. Thus far, research on their safety has focused on comparisons with other types of intersection and the effects of physical lane dividers. This study investigates crash patterns at German turbo roundabouts, based on a largely complete sample of such roundabouts and detailed data on infrastructure characteristics, traffic volumes and crashes. We calculate the crash rates for turbo roundabouts as a whole, as well as for their individual elements, including entries and exits, and the circulatory roadway. In addition, crash constellations are analysed and crash prediction models are computed, for all crashes and for the two most relevant crash constellations right-of-way and rear-end crashes. The results confirm earlier research findings that turbo roundabouts effectively combine high capacity with high safety levels. The results add new insights, thanks to the more detailed analysis. Entries and right-of-way crashes are most relevant, followed by rear-end crashes which mainly occur at the circulatory roadway. Crash constellations differ significantly between the different elements of the roundabouts, traffic volumes increase crash numbers for all designs and elements. We find no significant effects of the different types of marked lane dividers in our sample, this suggests that drivers do not respect solid lines and that physical dividers are potentially needed to prevent drivers from changing lanes in the circulatory roadway. The detailed analysis of crash patterns in this study enables specific recommendations to be made for improving safety at turbo roundabouts further and exploiting their potential more effectively.
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Author Biographies
Armin Kollascheck, Dresden University of Technology, Germany
Dipl.-Ing. Armin Kollascheck is a research assistant at the Chair of Mobility System Planning at TUD Dresden University of Technology. He studied traffic engineering transport planning and worked as student assistant at Hoffmann-Leichter Engineering Consultancy mbH. His research interests include road traffic safety and automated methods to measure and analyse road traffic and mobility.
CRediT contribution: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Software, Visualization, Writing—original draft, Writing—review & editing.
Martin Bärwolff, The Federal Autobahn GmbH, Germany | Dresden University of Technology, Germany
Dipl.-Ing. Martin Bärwolff was a research associate at the Chair of Integrated Transport Planning and Traffic Engineering at TUD Dresden University of Technology, and now works at the Autobahn GmbH of the federal government. After studying traffic engineering in Dresden, he is now a PhD student, and co-founded platomo, a start-up specialised in the development of hardware, software and automated methods for data-driven analysis and modelling of traffic and mobility. His research interests focus on traffic safety in general as well as traffic behaviour of vulnerable road users and automated methods to measure and analyse traffic and mobility.
CRediT contribution: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Software, Writing—original draft.
Julian Schmitz, Ruhr University Bochum, Germany
Dr.-Ing. Julian Schmitz is research assistant at the Institute for Traffic Engineering and Management at Ruhr-University Bochum. He has worked on several research projects on traffic flow and safety at different types of urban intersections. He recently completed his doctorate on the capacity of signalized intersections.
CRediT contribution: Conceptualization, Data curation, Formal analysis, Visualization, Writing—original draft.
Justin Geistefeldt, Ruhr University Bochum, Germany
Prof. Dr.-Ing. Justin Geistefeldt is professor and head of the Institute for Traffic Engineering and Management at Ruhr-University Bochum. His major research interests include highway capacity and quality of service analysis, traffic flow theory, macroscopic and microscopic traffic simulation, road safety analysis, and traffic management.
CRediT contribution: Conceptualization, Supervision, Writing—original draft, Writing—review & editing.
Sebastian Hanteschel, Dresden University of Technology, Germany
Dr.-Ing. Sebastian Hantschel is a postdoc researcher at the Chair of Mobility System Planning at TUD Dresden University of Technology. He finished his PhD in 2022 that analysed determinants of bicyclists' behaviour and safety in mixed traffic situations on major roads in urban areas. His research interests focus on traffic safety and safety-related behaviour of vulnerable road users.
CRediT contribution: Supervision, Writing—review & editing.
Regine Gerike, Dresden University of Technology, Germany
Prof. Dr.-Ing. Regine Gerike is head of the Chair of Mobility System Planning at TUD Dresden University of Technology. Before joining TUD, she chaired the Institute for Transport Studies at the University of Natural Resources and Life Sciences (BOKU) in Vienna, Austria. From 2008 to 2012 she was assistant professor at Technical University of Munich, head of the Research Centre Mobility and Transport and of the PhD-program “mobil.LAB Sustainable Mobility in the Metropolitan Region of Munich”. Her research interests include transport planning and traffic safety with a focus on vulnerable road users.
CRediT contribution: Conceptualization, Supervision, Writing—original draft, Writing—review & editing.
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Copyright (c) 2025 Armin Kollascheck, Martin Bärwolff, Julian Schmitz, Justin Geistefeldt, Sebastian Hanteschel, Regine Gerike
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