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.
- ItemThe Use of a Suitable Simulation Tool for Traffic Modelling(Vysoké učení technické v Brně, Fakulta strojního inženýrství, Ústav automobilového a dopravního inženýrství, 2023-09-06) Maxera, Pavel; Semela, Marek; Kledus, Robert; Bilík, Martin; Bradáč, AlbertThis paper focusses on traffic modelling, which is very relevant to the field of transport planning. The usability of the AnyLogic simulation software is illustrated in the form of a case study at a selected intersection. It is a universal simulation tool that can be used in many research fields (for example, in transportation, logistics, traffic, pedestrian movement, etc.). Using multimethod simulation modelling enables the creation of a wide range of different models with varying levels of detail. The case study evaluated the current state of the intersection during rush hour using simulation. Subsequently, the intersection modifications were designed and simulated in the form of traffic light installation and reconstruction into a roundabout. The comparison of the results showed that both proposed modifications would contribute to improving the current state, that is, eliminating the congestion and strengthening the traffic flow. The best results were achieved with the roundabout variant. The analysis confirmed the suitability of using AnyLogic software to solve this type of problem.
- ItemLet It Crash! Energy Equivalent Speed Determination(SciTePress, 2021-04-30) Moravcová, Pavlína; Bucsuházy, Kateřina; Bilík, Martin; Belák, Michal; Bradáč, AlbertCrash analysis including calculation of the impact speed and related determination of deformation energy is one of the main assumptions for the clarification of mostly negligent crimes. In this article were introduced results of two crash tests representing the comparison of the stiffness and technological obsolescence and their influence on the resulted vehicle deformation. Different extent of vehicle deformation was used to demonstrate the limits of selected methods for Energy Equivalent Speed determination as a value which expresses the kinetic energy dissipated by the vehicle during the contact phase.
- ItemMultimodal Features for Detection of Driver Stress and Fatigue: Review(IEEE, 2021-06-01) Němcová, Andrea; Svozilová, Veronika; Bucsuházy, Kateřina; Smíšek, Radovan; Mézl, Martin; Hesko, Branislav; Belák, Michal; Bilík, Martin; Maxera, Pavel; Seitl, Martin; Dominik, Tomáš; Semela, Marek; Šucha, Matúš; Kolář, RadimDriver fatigue and stress significantly contribute to higher number of car accidents worldwide. Although, different detection approaches have been already commercialized and used by car producers (and third party companies), research activities in this field are still needed in order to increase the reliability of these alert systems. Also, in the context of automated driving, the driver mental state assessment will be an important part of cars in future. This paper presents state-of-the-art review of different approaches for driver fatigue and stress detection and evaluation. We describe in details various signals (biological, car and video) and derived features used for these tasks and we discuss their relevance and advantages. In order to make this review complete, we also describe different datasets, acquisition systems and experiment scenarios.