The operational safety assessment of the unmanned vehicles is crucial for their subsequent practical use. The safety limit criteria used for the operation assessment, especially values closely related to the safety of persons and their vulnerability to collision with these vehicles, represent nowadays a significant limitation. This contribution presents the currently discussed and proposed human safety criteria for the UAS, evaluates the available data from the collision dynamic tests and computer modelling and provides the possibility to compare and evaluate these criteria on a validated set of data. A total of five small UAS, three multi-rotor quadcopters and two fixed-wing aircrafts were used to verify the current methods and serve as a basis for the assessment. The results of the measurements obtained through the crash tests demonstrate the excessive restrictiveness of the currently used kinetic energy threshold values and the limited value of some proposed criterions, e.g. the blunt criterion. On the contrary, they point to the appropriateness of the application of car vulnerability criterions. The UAS mass or kinetic energy tests represent an easily definable threshold value, however, the available data sets and the tests performed showed limitations of its applicability for the deformable and fragile UAS structures. The article aims to verify, based on its own impact tests, the adequacy of the evaluation of the safety criteria of the UAS operation in relation to the development of the current legislation that defines the conditions of use of these machines.
The paper focuses on road safety assessment. The main objective was to assess the impact of different types and sizes of advertising devices as a potential distraction for drivers. Distraction of driver’s attention in real traffic was evaluated using the “Wiener Fahrprobe” structured observation method. As a method for reliable data collection, the eye tracking method was used to accurately define the time delay caused by the observation of the advertising device. As part of the assessment of the direct impact on drivers, test runs were carried out with 40 drivers on a pre-defined section of road on which different types of advertising devices were present. As an additional, supporting measurement, a vehicle simulator was also used. From the obtained knowledge it was possible to create a unique classification system that can be used to assess the severity of any installed advertising device in general. In the case of distraction, it was found that dynamic advertising devices attract the most attention than conventional static devices and appear to be a significant risk to road safety.
This study investigates the safety risks of Unmanned Aerial System (UAS) collisions with humans, focusing on impact dynamics through controlled crash testing. Utilizing a custom-designed drop mechanism, 49 impact tests were conducted on a Hybrid III anthropomorphic test device at various velocities and kinetic energies (7–24 m/s and 1–280 J). Tested UASs included a range of designs and weights (20 g to over 1 kg). Results demonstrated limitations in using kinetic energy models and peak head acceleration for injury prediction. The Head Injury Criterion showed greater consistency, reflecting the temporal profile of impacts. Findings revealed that UAS structural fragility reduces energy transfer at higher impacts through deformation and fracturing. This work underscores the need for improved testing protocols and nuanced safety standards.
The paper presents a methodology for determination and evaluation of the influence of advertising equipment on the road traffic safety. Research is based on analysis of advertisement along the primary road network in the Czech Republic and defines individual measures to resolve identified issues. Proposed solutions are based on combination and synthesis of various methodological approaches, including statistical evaluation and analysis of traffic accidents, monitoring of traffic conflicts, psychological analysis of impact of the presence of advertising equipment on the driver in real and simulated scenarios, analysis of the number and length and the point of driver's gaze utilizing Eye-tracking techniques and assessment of the advertising equipment as a light emitting object.
8 March 2021 in Advances in Structural Engineering
The article presents a mobile anti-vehicle barrier created from a high-performance fibre-reinforced concrete, which resembles a historical design of the Czech Hedgehog barrier. The performance of this design when subjected to a moderate velocity vehicle impact was evaluated. A preliminary crash test provided basic data to perform an optimisation of the design using numerical simulations conducted in LS-DYNA. Several key observations were made regarding the crucial role of the barrier-surface interactions and overall barrier behaviour. Based on the simulations, improved geometry of the barrier was proposed and subjected to more full-scale crash tests with various barrier placements. The improved barrier design was able to stop an ordinary road vehicle weighing 1300 kg moving with a velocity of 48 km/h while retaining beneficial characteristics, most importantly low weight.