Saulius Nagurnas

Evaluation of Veracity of Car Braking Parameters Used for the Analysis of Road Accidents

Abstract During the road accident analysis speed of the examined vehicle often is being established in accordance with the length of the trace remained by the vehicle tires. Usually in such case there are values of braking deceleration used for calculations, which are selected from the corresponding references. The real experiment, establishing the braking parameters of the given vehicle, is performed more seldom. In both cases it is important to calculate the vehicle speed in accordance with the received or found values of deceleration as well to estimate the possible limits of the vehicle speed, i.e. to evaluate the veracity of such calculations. This paper presents the results of evaluation of car braking parameters, which are treated as random values in the known probabilistic characteristics.

Analysis of calculation methods used for accuracy evaluation of the results of road accident examination

Abstract For examination of road accidents often calculations are being performed according to mathematical equations having many variables, real values of which are of stochastic nature and they depend on many accident factors. Therefore it is important to know limits of determination of final values of every being analysed parameter of car movement and their probabilistic characteristics. This paper presents some cases of simulation of some road situations by mathematical methods of calculations, which now are widely used for evaluation of accuracy of values of the calculated parameter (in this paper ‐ the braking distance). Also here is presented some analysis of these methods. The paper presents the following cases of car braking: braking with making attempts to prevent a collision with another car, braking through impact‐to‐pedestrian prevention and conventional (rectilinear) car braking. The main attention in the analysis of the mentioned road situations is paid to veracity of the car braking distan...

The Research on Competitiveness of Road Transport Enterprises: Lithuanian Case

The Research on Competitiveness of Road Transport Enterprises: Lithuanian Case In the paper, various opinions of Lithuanian and foreign authors of scientific publications are reviewed and the criteria for assessing competitiveness of road transport are discussed upon. On assessment of competitiveness of services provided by Lithuanian road transport enterprises, not only technical options are taken into account. It is proposed to assess competitiveness of enterprises upon taking into consideration the total set of services provided as well as their quality and the marketing level of the enterprise. In the paper, the factors impacting competitiveness of road transport are discussed upon and the research works required for objective assessment of competitiveness of road transport are foreseen. A model for assessing competitiveness of road transport enterprises realized by the authors is provided. In the end of the paper, conclusions and recommendations are provided. Autotransporta uzņēmumu konkurētspējas izpēte: Lietuvas piemērs Autori rakstā parāda autotransporta konkurētspējas novērtēšanas kritērijus, pamatojoties uz lietuviešu un aizrobežu zinātnieku pētījumu rezultātiem. Pakalpojumu konkurētspējas novērtēšanā raksta autori iesaka neaprobežoties tikai ar tehniskām iespējām, bet gan analizēt visu piedāvāto pakalpojumu paketi, to kvalitāti un uzņēmuma mārketingu. Rakstā tiek parādīti faktori, kas ietekmē autotransporta konkurētspēju. Bez tam tiek pētīti faktori, kas ietekmē autotransporta pakalpojumu izvēli. Rakstā tiek piedāvāts modelis autotransporta uzņēmuma konkurētspējas novērtēšanai, ko ir aprobējuši Lietuvas autotransporta eksperti.

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.

Welds of Dissimilar Steel 1.0038/1.4301: Increasing Corrosion Resistance by the Optimization of Welding Parameters and Post-Weld Processing

The corrosion of exploited motor vehicles and important or potentially dangerous structures is not a new problem of engineering [1]. However, nowadays, it still remains one of the most burning questions of manufacturing welding structures. There are a number of established methods and technological solutions allowing improvements to the premature corrosion resistance of exploited welded joints and structural elements. In the majority of cases, different protective coatings are used. However, protective coatings are not applicable for some structures in food and medical industry as well as for some other big dissimilar-material structures of a complicated shape. In such cases, the corrosion resistance of welded structures may be provided by other technological means. The present research is aimed at investigating the efficiency of such methods. Several different welding technological solutions and post-weld surface treatments have been applied. The corrosion resistance of the obtained welded joints has been evaluated conducting tests on corrosion under laboratory conditions. The obtained results and conclusions of the present research may be useful for manufacturers solving the problems of the corrosion resistance of welded dissimilar-steel structures.

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.

Use of Mathematical Methods of Statistics for Analyzing Engine Characteristics

For the development of new models, automobile manufacturers are trying to come up with optimal software for engine control in all movement modes. However, in this case, a vehicle cannot reach outstanding characteristics in none of them. This is the main reason why modifications in engine control software used for adapting the vehicle for driver’s needs are becoming more and more popular. The article presents a short analysis of development trends towards engine control software. Also, models of mathematical statistics for engine power and torque growth are created. The introduced models give an opportunity to predict the probabilities of engine power or torque growth after individual reprogramming of engine control software.

Research of braking peculiarities of used cars

Abstract This paper briefly describes some analysis of a car braking process — the peculiarities of car wheel-to-road adhesion, the influence of distiibution of braking forces on car stability between front and rear axles. The requirements of EU Directive 71/320/EEC to braking force coefficients of car front and rear axles are exposed. Structural designs of braking systems are analyzed with respect to their meeting the EU standards. Experimental measurements ofbraking force coefficients for some models of cars which are used in Lithuania, are presented with the analysis how these coefficients meet the EU standards. The analysis of test results, suggestions for the ratio of braking forces of car front and rear axles are presented.