How accurate do car driver report their travelled speed before an accident: a comparison with insights of the Event Data Recorder

Karen Tschech; Thomas Schenk; Daniel Popp; Volker Alt; Stefanie Weber

doi:10.55329/vtum4072

Authors

Karen Tschech University Hospital Regensburg, Germany https://orcid.org/0009-0009-8415-1810
Thomas Schenk AUDI AG
Daniel Popp University Hospital Regensburg, Germany
Volker Alt University Hospital Regensburg, Germany
Stefanie Weber University Hospital Regensburg, Germany https://orcid.org/0009-0004-2149-3948

DOI:

https://doi.org/10.55329/vtum4072

Keywords:

car accident, Event Data Recorder (EDR), reporting accuracy, self-report, self-reported speed

Abstract

Statements of drivers are often used to gain insights into accident causations, whose understanding is an important factor for the development of effective prevention strategies. The coming into effect of the General Safety Regulation 2019 led to an increasing availability of objective vehicle data in the form of Event Data Recorders (EDR) in Germany as well as the whole European Union. This creates the possibility to examine the accuracy of the driver statements in more detail. Among others, maladjusted vehicle speed is an important crash contributing factor. Therefore, a good understanding about the quality and applicability of the drivers' reported speed can be important. The goal of the present study is to examine the accuracy of speed reports from German drivers in the context of accident research. To this end, the reported speeds and speed violations were evaluated with respect to their consistency with the EDR data. Additionally, it was investigated whether there is a relationship between the accuracy of the statements and the role in causing the accident on the one hand and the time elapsed between the accident and the report of the driven speed on the other hand. Based on data from the Audi Accident Research Unit (AARU), this study compares drivers' self-reported speeds prior to an accident obtained by standardized telephone interviews with the respective recorded EDR speeds of the crash vehicles. It was shown that driver reported speed violations significantly less often and to a smaller extent than they were committed based on the EDR data. The reported speeds were significantly lower than the recorded speeds from the EDR data. Furthermore, this effect was significantly stronger for the other accident participants, which tended to underestimate their speed more than the accident causers. This result might be explained by a certain group of other accident participants which were driving very fast (> 200 km/h) on the motorway, as is elaborated in detail in the discussion. There was no significant correlation between the accuracy of the reported speed and the timing of the respective interviews. In conclusion, the drivers’ statements regarding the driven speed were found to be relatively inaccurate, which is why they can only be used with caution and in conjunction with more reliable data. Still, the reported speed can be valuable to evaluate the general plausibility of the drivers' statements concerning the accident.

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Author Biographies

Karen Tschech, University Hospital Regensburg, Germany

Karen Tschech is the coordinator of the psychological team of the AARU at the Regensburg University Medical Centre since 2017. She holds an M.Sc. degree (2017) in Psychology from the University of Trier and received her PhD (2025) at the University of Regensburg. Her research focus is analysing accidents in depth from a psychological perspective, particularly with regard to the causes of accidents. Her PhD thesis is about the plausibility and accuracy of driver statements compared to the insights of the EDR.

CRediT contribution: Conceptualization, Formal analysis, Investigation, Methodology, Writing—original draft.

Thomas Schenk, AUDI AG

Thomas Schenk is project manager of the AARU at the site of the AUDI AG and responsible for the technical investigation of the accidents. He is part of the AARU's technical team since 2002. He holds a diploma in vehicle engineering from the University of Applied Sciences for Technology and Economics Dresden, Germany. His research interests cover in-depth accident analysis including the performance of electric vehicles, especially in the event of an accident, and improving the handling of the post-crash phase.

CRediT contribution: Project administration, Writing—review & editing.

Daniel Popp, University Hospital Regensburg, Germany

Daniel Popp is project manager of the AARU at the site of the Regensburg University Medical Centre. He is coordinator of the AARU's medical team since 2020. He is Associate Professor and Senior Physician at the Department of Trauma Surgery at the University of Regensburg, Germany. His research topics cover trauma surgery, including polytrauma and the outcome of injuries that occurred in traffic accidents.

CRediT contribution: Writing—review & editing.

Volker Alt, University Hospital Regensburg, Germany

Volker Alt received his MD and PhD at the University of Heidelberg and University of Giessen, Germany. His main research topics are trauma surgery, including polytrauma, fractures and complications after trauma, such as bone healing disturbances. Since 2019, he acts as Director and Chairman of the Department of Trauma Surgery at the University of Regensburg, Germany and as Medical Director of the AARU.

CRediT contribution: Funding acquisition, Writing—review & editing.

Stefanie Weber, University Hospital Regensburg, Germany

Stefanie Weber is project manager of the AARU at the site of the Regensburg University Medical Centre. She is part of the AARU since 2009. She received her diploma in psychology (2008) at the University of Regensburg and holds her PhD (2015) from the University of the Bundeswehr Munich. Her research interests cover the prevention of accidents from a psychological perspective, including accident causations, and standard reactions in critical driving situations.

CRediT contribution: Conceptualization, Methodology, Project administration, Supervision, Writing—review & editing.

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