Odbor znalectví ve strojírenství, analýza dopravních nehod a oceňování motorových vozidel
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- ItemWhat should I use to calculate vehicle EES?(PUBLIC LIBRARY SCIENCE, 2024-02-08) Moravcová, Pavlína; Bucsuházy, Kateřina; Zůvala, Robert; Semela, Marek; Bradáč, AlbertComprehensive crash analysis includes calculating impact speed, which requires the determination of kinetic energy expended on the deformation of the vehicle's structural elements at the point of contact during a collision. The accuracy of the input data affects the resulting analysis of the crash. Therefore, this article aims to analyse selected factors influencing the determination of Energy Equivalent Speed (EES) determination using the CRASH3 algorithm: the extent of damage using defined measurement points, deformation width, and also limit speed b0. The variables were varied depending on selected factors such as the extent of damage, the type of collision (overlap), and also vehicle type (vehicle category classification). The presented study concluded that using 2 equally spaced measurement points to define the deformation profile should not be recommended in forensic practice when using CRASH3 algorithm. Using 7 measurement points seems more appropriate in case of equal spacing, even though the differences in calculated EES are not high when using 5 or 6 measurement points, especially with respect to the inaccuracy/technically acceptable tolerance of the EES value determination. The resulting EES is significantly influenced by variation of the deformation width. The used b0 range had a significant effect on the resulting EES value only in the case of SUVs. These vehicles show higher stiffness, which supposes the use of lower b0 values should not be recommended.
- ItemSafe or unsafe driving maneuvers in road traffic(Palacký University in Olomouc, 2017-12-18) Tokař, StanislavThis article represents an area closely connected to the analysis of road accidents. When the act of accident is being considered by an expert, it often happens that one participant of the accident causes that the other participant has to change suddenly the speed or direction of his/her drive to prevent possible collision. For a proper consideration of the driving manoeuvres we need to know the limit of a sudden change of speed or a sudden change of direction of drive. The limit of suddenness can be taken as the limit between a safe and already unsafe driving manoeuvre (braking, transverse motion) of the vehicle. The author tried to settle this limit by measurements with respondents who were asked to subjectively classify particular driving manoeuvres. For classification of the sudden change of speed, the intensity of deceleration was altered (3 m/s2, 5 m/s2, 7 m/s2, and maximum attainable deceleration amax m/s2). At classifying a sudden change of direction, we changed the trajectory of the vehicle´s motion with transverse motion in one curve. As a result in the change of trajectory, the magnitude of side acceleration changed (values of side acceleration 2 m/s2, 3 m/s2, 4 m/s2 and 6 m/s2). From the results achieved it can be settled that the limit of a sudden change of vehicle´s speed went round a half of maximally achievable braking deceleration of personal vehicles, at approximately 3,8 to 4,8 m/s2. The limit of a sudden change of direction of drive went between 2,7 and 3,5 m/s2.of vehicles´ side acceleration. Achieved knowledge can be used in the sphere of road accident analysis when classifying driving manoeuvres of individual participants of the scene of accident. All measurements were taken with personal vehicles, thus it is possible to pay further attention to setting the limit of a sudden change of speed and direction of drive with utility vehicles, lorries and trucks, respectively.
- ItemHow to Assess the Dangerousness of Driving Situations at Pedestrian Crossings(EVU, 2023-10-05) Maxera, Pavel; Kledus, Robert; Semela, Marek; Bilík, Martin; Bradáč, Albert; Rak, MartinThe paper analyzes drivers' behavior when solving complex driving situations at pedestrian crossing locations. The findings of the research are based on a detailed analysis of 129 driving tests carried out in real road traffic. The results of the evaluation clarify important characteristics of drivers' behavior at pedestrian crossing locations. Of particular importance are the findings on when pedestrians become an important visual stimulus for drivers, how the driver's behavior affects the complexity of the driving situation, and the overall design of the location where pedestrians cross. From these findings, appropriate criteria for assessing the hazardousness of such driving situations are derived, and limits are found. These limits allow, based on relatively easy-to-detect quantitative data, to determine the dangerousness of a particular driving situation in real road traffic. According to the authors, the findings are particularly useful in assessing the ability of road users to prevent an accident from occurring. Using the results allows experts to assess better the causal links associated with traffic accidents, thus facilitating a further legal assessment.
- ItemThe Comparison of 3D and 2D Measurement Techniques Used for the Analysis of Vehicle Deformation(SciTePress, 2020-05-04) Moravcová, Pavlína; Bucsuházy, Kateřina; Zůvala, Robert; Bilík, Martin; Bradáč, AlbertAs one of the main assumptions for the accident analysis has been detailed information about vehicle deformation. The precise deformation depth allows to quantify deformation energy and related impact speed. The aim of this paper has been the comparison of two selected methods used for the determination of deformation depth. For the purpose of this paper were selected top-view photography as basic and cheap method and 3D scanning as modern and advanced method. Different vehicles and 2 basic types of damage - frontal and side impact - were chosen for the analysis. Also, the different range of vehicle deformation depth were selected. On the basis of obtained results is possible to determine the applicability of these methods, their advantages and limitations.
- ItemTeorie a praxe analýzy silničních nehod(Nakladatelství VUTIUM, 2024-04-30) Bradáč, Albert; Semela, Marek; Kledus, Robert; Bilík, Martin; Křižák, Michal; Mikulec, Roman; Bucsuházy, Kateřina; Belák, Michal; Mičunek, Tomáš; Frydrýn, Michal; Nouzovský, Luboš; Svatý, Zdeněk; Radová, Zuzana; Fryšták, Marek; Vojtíšek, Tomáš; Pokorný, Jan; Berg, JanOdborná kniha se zabývá komplexním systémovým přístupem k analýze silničních nehod, obsahuje moderní metody dokumentace i analýzy silničních nehod vč. příkladů a zohledňuje změny v právním prostředí znalecké činnosti