Vidas Žuraulis

The impact of road roughness on the duration of contact between a vehicle wheel and road surface

AbstractThe paper analyses the impact of the road micro-profile on the duration and the type of the vehicle wheel contact with the road surface driving at different speed. The selected vehicle bicycle model describes vertical displacements of front and rear wheels and their suspension as well as the impact of the vehicle body motion and longitudinal oscillation. International Roughness Index (IRI) and micro-profile irregularities of the road section analysed in the paper were identified using specialized road testing equipment. The experimental investigations measuring the vehicle suspension displacement and the body acceleration were carried out. Frequency characteristics of suspension motion and regularities of vertical movement of the wheel were identified after dividing the investigated road section according to driving modes. The analysis into the wheel contact with the road surface and identified correlations enable to determine the vehicle stability on selected quality roads.

The Improvement Conception of Drivers Training and Examination System in Lithuania

The current paper presents the structure of the drivers training and examination system existing in Lithuania and describes the interrelations between the institutions involved in the said process. In course of analysis of models of drivers training and examination systems of various countries, their advantages and imperfections are highlighted. The experience of Germany, Holland, Sweden and Great Britain in the sphere of training and examination of motor vehicles drivers is described. In the end of the paper, conclusions and recommendations for improving the quality of drivers training and examination system as well as traffic safety in Lithuania are provided.

The analysis of drivers’ reaction time using cell phone in the case of vehicle stabilization task

OBJECTIVES The article analyzes the drivers psychophysiological qualities such as complex reaction and individual ability to control the vehicle that has suddenly lost its stability. The comparative analysis of the duration of reaction time was performed to assess the negative influence of speaking on a phone and driving with one hand. MATERIAL AND METHODS The experimental research was carried out on special training grounds with the road surface having low adhesion coefficient, where sudden lateral vehicle destabilization was caused by the moving plate mounted on the road surface. The vehicle onboard equipment was used for identifying the difference between the destabilization moment and the responsive drivers steering wheel movement which in this research was assumed as the reaction time. RESULTS Statistical methods of research applied for the analysis of results showed high probability that the drivers actions would be significantly late in controlling a vehicle. When stabilizing a vehicle movement, the complex reaction time of a vehicle driver speaking on a mobile phone is increased by 18.1% as compared with the conventional driving by a driver not speaking on a phone. CONCLUSIONS The risk of using the phone depends on the driver characteristics, traits and attitudes that affect the level of their experienced dangers, and the intensity of using mobile phones and driving. Speaking on a phone while driving increases the drivers reaction time and mental workload, and changes his or her visual overview ability as well as understanding of the situation. Int J Occup Med Environ Health 2018;31(5):633-648.

Research Into The Reliability Of The Bridge Of A Car Carrier Platform

The paper deals with the strength analysis of structural devices (platform bridges) that fasten cars to a car carrier frame. The loads of all bridges are evaluated along with the indication of the areas of load concentration. The paper presents a brief structural description of platform bridges, including their drawings performed with the help of SolidWorks software. The bridge loads have been analyzed applying Ansys software. According to the results of computer simulation of the loads, dangerous structural areas of the bridges have been identified. While making attempts to solve the established structural problems of such car carriers, suggestions for their structural improvement have been put forward, and computer simulation of loads and stress spread have been performed. The paper ends with conclusions and suggestions.