Analyse glättebedingter Unfälle von Güterkraftfahrzeugen mit mehr als 12 t zulässigem Gesamtgewicht

[Analysis of accidents related to slippery road conditions of heavy goods vehicles with more than 12 t total permissible weight]
Auteur(s)
Müller, G.; Thüring, M.; Jänsch, M.; Epple, S.; Kretschmer, F.; Gottwald, Y.L.; Oehring, F.; Winkenbach, A.

Jaar

Exceeding the possible friction coefficient potential between the road surface and the tire still represents a major safety risk. While systems are now being developed that can estimate the current friction coefficient potential quite reliably, the question arises as to the best way to communicate this information to the driver. This and other questions regarding the usefulness of a friction value warning are answered in this project. During this project, the benefits of a friction value warning for heavy trucks (N3) were investigated. By means of a test person study in the driving simulator of the Technical University of Berlin, it was possible to determine driving behaviour that would have positive effects in the event of a slippery road accident. The basis was initially formed by a literature research, which revealed both findings on the state of the art of driver assistance systems as well as insights into research on the design of warnings. Numerous details about the safety potential, the range of products offered by the various manufacturers, legislation and other aspects of driver assistance systems were explored, while cognitive models and the effects of warnings on a test person were investigated for the design of warnings. Consequently, together with an expert workshop and preliminary studies on the design of the different slippery-road-icons, it was possible to work out a scientifically sound warning strategy consisting of acoustic signals, voice information and graphic displays on a head-up display. In parallel, an overview of the accident situation of N3 trucks was obtained with an analysis of accidents of heavy trucks with reduced friction. For this purpose, the data of the GIDAS accident database were examined and a representative random sample of accidents in which reduced adhesion could have played a role was created. Two scenarios were considered: Rear-end collisions where the truck rear-ends another vehicle and driving accidents where the truck driver loses control of his vehicle. This accident analysis then formed the basis for the scenario design of the test person study in the driving simulator. Critical driving scenarios, unclear curves and uphill driving and the end of a traffic congestion behind a hill, each paired with rain, heavy rain or fog and the varying friction coefficient of the road, were presented in the driving simulator together with the warning strategy. In the test person study, truck drivers drove through the prepared simulations, whereby the experimental group received the slippery road warning and the control group drove through the same simulation without warning. The main questions that arose were whether the drivers with the warning system adapted their behaviour (especially their speed) to the condition of the road and whether the drivers with the warning system showed better driving performance in hazardous situations compared to drivers without the warning system. In addition, the study investigated how drivers rated the criticality of driving situations and how drivers rated the warning strategy. In summary, the study showed that the test subjects with a warning adapted their driving behaviour better to the slippery situation than test subjects without a warning. The former reduced their speed significantly earlier and more strongly. The developed warning strategy was evaluated as positive and helpful and was rated by the test persons with a high degree of acceptance. Due to the Corona pandemic, the sample size of the test persons was smaller than originally planned, which must be considered for the results. In the final part of this project, the concrete benefit of slippery road warning systems on HGVs was analysed in relation to accident occurrence. With the knowledge of the effect of a slippery road warning system on the driving behaviour of truck drivers, the truck accidents from the GIDAS database could be re-simulated by a forward reconstruction to determine what influence the slippery road warning system would have had on the accident. The analysis showed, among other things, that a slippery road warning system for trucks could be used in 12% of all accidents. Assuming a medium reduction in the driving speed of HGV drivers of 9.6 km/h at speed of 80 km/h due to the warning system, almost 30 % of collisions in solo accidents or accidents involving another vehicle would have been avoided for both HGVs and collision opponents. Furthermore, more than half of the trucks and collision opponents would have had lower collision severities. Using injury risk curves, it could be shown that the lower collision severities significantly reduced the risk of serious or more severe injuries. In the case of truck accidents with pedestrians, out of nine accidents analysed, two would have been avoided and seven accidents would have had the potential to reduce the injury severity of pedestrians due to the lower collision speed of the truck.

Rapportnummer
F148
Pagina's
89 + 47
Serie
Berichte der Bundesanstalt für Straßenwesen, Reihe F: Fahrzeugtechnik
ISBN
978-3-95606-709-9
ISSN
0943-9307
Bibliotheeknummer
20220386 ST [electronic version only]
Gepubliceerd door
Bundesanstalt für Strassenwesen BASt, Bergisch Gladbach

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