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Electrical vehicles have the ability to partially recover some kinetic energy during braking. Kinetic energy is transformed into electric energy, which is fed to the battery by the control system and stored there for further use. The aim of this paper was to analyse the levels of energy recovered by an electric vehicle during braking at various speeds and with different braking intensities. The first phase of testing consisted of vehicle braking tests in real-life conditions. The registered speed profiles were then used as input data for the simulation software. The authors have also analysed the effect of the state of charge of the battery and of the vehicle’s load on the amount of energy recovered during braking. The performed simulation tests demonstrated that the level of recovered energy is significantly affected by the initial braking speed and by the force of pressure applied to the brake pedal. The amount of recovered energy is less affected by the state of charge (SOC) of the battery and by the vehicle’s load. Energy regeneration during braking is currently an important research topic. The efficiency of an electric vehicle depends on the range, which can be extended thanks to the additional energy recovered during braking maneuvers. The presented preliminary simulation results are intended to assess the level of energy recovery in electric vehicles. The authors are aware that a full, comprehensive analysis requires additional research using electric vehicles that will verify the results presented in the paper.

From an economic perspective, the purchase cost of an electric bus is greater than that of a conventional one. This results from the additional components of the bus drivetrain and the costly charging infrastructure. However, it should be noted that electric bus ensures greener and more sustainable public transport. The presented study focuses on the economic and energy efficiency analysis of city buses with different types of driving system evaluated forselected urban and suburban routes. The routes differ in terms of the number of journeys per day, elevation, the daily distance travelled, and the daily operating time. The results demonstrate that driving conditions can affect economic efficiency. The Total Cost of Ownership (TCO) method used in the study shows that electric buses represent the highest TCO values among the vehicles taken into account. However, for the TCO calculated for electric and hybrid buses, fuel (energy) costs have a much lower share than for the TCO of conventional buses.

Safety is one of the most important issues in all areas of human life. It is taken into account during the design of motor vehicles, road infrastructure, the implementation of training for drivers, and their education. The main goal is to raise it, which is why it is discussed in many research studies. The research concerns the construction of motor vehicles, systems equipped with them, infrastructure, as well as drivers, their behavior, and the way they are driven. This article presents tests of the method of driving a vehicle in real road conditions. To evaluate the driver, selected vehicle motion parameters were used, which were recorded while driving on a real test section characterised by changing traffic conditions.

Vehicles, regardless of the type of drive, move on different types of roads. The operational characteristics of the highway will be different than those of the urban road. The aim of this article is to compare the performance of electric, hybrid, and conventional vehicles on different roads. For simulation studies in the AVL Cruise program, speed profiles determined on the highway, expressway, suburban, and urban roads were used. The article presents the course of energy consumption of an electric and hybrid vehicle, the amount of energy recovered by these vehicles, and the state of battery charge after the routes. The fuel consumption and emissions of harmful exhaust components of hybrid and conventional vehicles are also described. Based on the collected data, it was determined what is the cost of driving each of the routes by the tested vehicles. The results showed that the operational characteristics of the vehicles on each route are different. Driving speed, vehicle load, or duration of the journey significantly affects energy consumption, fuel, and costs. Such a comparison allows you to adjust the choice of vehicle by the driver, who, knowing his daily route, can decide on a vehicle with a specific type of drive.

In recent years, there has been a significant increase in the number of buses operated by urban public transport companies powered by alternative fuels and equipped with alternative drive systems. In addition to economic factors, operators should also take environmental aspects into account when purchasing new vehicles. In this case, a useful criterion for selecting a vehicle is the Life Cycle Cost (LCC), which, in addition to the cost of purchasing a bus, takes into account the necessary expenses associated with its maintenance, operation, decommissioning, as well as emissions costs. This paper presents a study of the LCC values, estimated for the entire bus fleet based on several bus replacement variants, taking into account different shares of alternative buses in the transport fleet. Analyses have shown that replacing conventional buses by the compressed natural gas (CNG) powered buses will reduce life cycle cost by 27% compared to the LCC level in 2019. Increasing the share of electric buses in the fleet will significantly reduce the level of emissions of harmful substances contained in exhaust gases.

The article presents an assessment of the state of safety on Polish roads in the period 2004-2018 in terms of changes that occurred after Poland’s accession to the EU. The number of vehicles in the period in question was analyzed and the annual growth of the number of vehicles of the main types was assessed. Analysis of changes in the length of the most important road types was carried out. The number of accidents and fatalities was analyzed and the changes in this area were assessed. The statistical decrease in the number of accidents and fatalities, as well as a very strong correlation between them, were confirmed. It was indicated in which groups of accidents the fatality risk is the highest. The paper presents a summary of the types of roads on which traffic accidents and fatal traffic accidents occurred. Shares of these roads were determined, indicating that the most dangerous roads in Poland are the two-way, two-lane roads.

The conditions of use of the vehicle significantly affect the performance results. Traffic conditions in a specific city directly affect the consumption of energy, fuel and emissions of harmful compounds in exhaust fumes. Conduction of the measurements of a vehicle’s performance parameters in operating conditions is very troublesome and is often not possible to realize. An alternative is to use the simulation programs. Vehicle simulation programs offer options related to vehicle models or drive unit components and allow development of new models. Based on the results of simulation testing, it is possible to analyse the level of fuel and energy consumption as well as emissions of harmful compounds in exhaust gases and the operating effectiveness of the drive system in the speed profile. The paper presents the evaluation of the effectiveness of using hybrid electric drive system in passenger cars in medium-sized city traffic conditions using the Kielce example. The simulation tests were based on the speed profiles recorded during real-world test drives in various times of the day. The simulation results were used to conduct an analysis of fuel consumption and pollutant emissions recorded by conventional and hybrid vehicles.

The aim of this study was to analyse the driver behaviour in simple and complex car-following situations under day- and night-time lighting conditions (four scenarios). Nearly 70 drivers participated in the tests, each taking several trials, during which they were exposed to randomly selected situations. The tests involved driving along a two-lane motorway with a vehicle in front and responding to its sudden braking. Different distances between the vehicles were simulated. The scenarios varied in complexity ranging from none to some vehicles around the subject vehicle. The study involved measuring different reaction times, i.e. the time to release the accelerator pedal, the time to apply the brake pedal and the time to start steering, to find out how the particular emergency manoeuvres contribute to the occurrence of collisions in the four scenarios. The results show that both the complexity of a road situation as well as the lighting conditions determine the type of emergency manoeuvre undertaken and the time of the driver reaction.

The safety of road users is one of the priority issues taken into account in both the operation and design of vehicles. The presented work is part of a study that aims to develop a method for parametric assessment of driver behavior. The driving style of a driver depends on their skills and psychophysical characteristics, the type and performance of the vehicle used by the driver, and the type of road. This method involves the continuous measurement of the longitudinal and lateral acceleration values of a vehicle body. The paper analyzes how the type of road influences the structure of the maneuvers undertaken by the driver. The paper formulates criteria for distinguishing basic maneuvers (acceleration, braking, and turning). The structure of maneuvers was analyzed for two parameters: the extreme value of acceleration occurring during the execution of a given maneuver and the frequency of maneuvers during the passage of a given route. The analysis presented in this paper confirms that the type of road has a significant influence on the structure of the maneuvers undertaken by the driver.

There is a range of anxiety-related phenomena among users and potential buyers of electric vehicles. Chief among them is the fear of the vehicle stopping and its users getting “stuck” before reaching their designated destination. The limited range of an electric vehicle makes EV users worry that the battery will drain while driving and the vehicle will stall on the road. It is therefore important to know the factors that could further reduce the range during daily vehicle operation. The purpose of this study was to determine the effect of selected parameters on a battery’s depth of discharge (DOD). In a simulation study of an electric vehicle, the effects of the driving cycle, ambient temperature, load, and initial state of charge of the accumulator on the energy consumption pattern and a battery’s depth of discharge (DOD) were analyzed. The simulation results confirmed that the route taken has the highest impact on energy consumption. The presented results show how significantly the operating conditions of an electric vehicle affect the energy life. This translates into an electric vehicle’s range.

The role of the road transportation of people and goods is increasing [...]

The subject of the considerations presented in this article are experimental braking performance tests carried out on dry surfaces for three selected vehicle types: passenger vehicle, delivery truck and touristic bus. The paper describes factors affecting braking performance. The tests were repeatedly carried out on dry asphalt pavement using specialized testing equipment. The deceleration was determined as a function of time and the maximum deceleration values were determined. Statistical analysis of the obtained results was performed, mean values and values of standard deviation were determined. Based on the conducted experiments, it can be stated that the maximum deceleration braking on asphalt surface depends on the type of vehicle. For a passenger vehicle it can reach even 12m/s2.

The article presents a review of the main indicators of driving quality and vehicle safety. These indicators allow to characterize the behavior and skills of a given driver and to compare them with each other. They are also the basic measurable source, which is very important in the aspect of research. The research itself, through the use of indicators, makes it possible to assess the quality of driving and the safety performance of the activity. The literature contains a number of definitions relating to the indicators presented, which differ from one another. This makes the definition adopted and therefore the methodology of measurement is often different and comparing test results makes no sense. Therefore, the article contains the most popular and accurate terms and definitions of these indicators, which have also been graphically interpreted as far as possible.

The study analyzes the relation between vehicle traffic parameters, i.e. volume, speed, noise and road accidents within the time period of one year. The data regarding the number of accidents was obtained from the Polish Accident and Collision Records System (Polish abbreviation - SEWIK). Traffic flow, vehicle speed and urban traffic noise were recorded by two traffic and noise monitoring stations at Krakowska and Lodzka streets in Kielce in 2013. The road noise was calculated according to the Cnossos-EU method and compared with measured values. Relation between the median of the number of traffic accidents, traffic volume, vehicle speed and noise in subsequent hours of the day was analyzed. High values of the correlation coefficient calculated for the relationship between the number of road accidents and traffic volume, speed and noise were found. In the case of Krakowska street (Road No 762), the values of this coefficient were, respectively: 0.88, -0.83 and 0.74. For Lodzka street (Road No 74), the values of the correlation coefficient between the tested parameters were 0.89, -0.82 and 0.85. The study showed that the largest number of road accidents occurs during the morning and afternoon rush hours. At these times of the day the noise is also the highest. The possibility of using the median of the road noise and traffic volume as a traffic accidents descriptor was examined.

For many institutions, it is important to evaluate a given driving technique as safe or unsafe based on measurable vehicle movement parameters. The paper constitutes a part of studies aimed at establishing a method of parameter-based evaluation of drivers in various road conditions, in other words, to create a so-called ‘driver profile’. The tests were carried out on a 650 km route, on four varying road types. Longitudinal and lateral acceleration values are used to evaluate the driving style. An analysis is presented of the impact of the type and shape of road on acceleration values. The results demonstrate that the same driver, when driving the same vehicle on an expressway, an inter-urban road or in urban traffic, will move with various acceleration values. A detailed analysis of acceleration values and distributions was conducted. Interesting conclusions were drawn after excluding the so-called ‘smooth driving’ sections, by acceleration ranges of −0.5 to 0.5 m/s2 from the analysis. This allowed for the evaluation of the structure of other longitudinal and lateral acceleration values. After this modification, the distributions showed specificity for the given road type, thereby allowing the road type used by the vehicle’s driver to be recognized based solely on the distribution.

The paper presents a design basis adopted for the construction of a test facility for the rig testing of rolling bearings. One of the methods of inspection of the bearings is the testing of the bearings as components having already been mounted in a specific machine component unit and tested in the conditions of operation of the unit as a whole. This article presents preliminary engineering requirements and the design of a special test rig for the examination of rolling bearings without the necessity of mounting the bearings in a specific machine component unit. The rig testing is widely used in consideration of numerous good points of such a method. The simulation testing of bearings (on test rigs) consists in reproducing as accurately as possible the real conditions of operation of the bearings when mounted in the device for which they are intended. The rigs used for such tests are complicated and expensive, but the results of such tests are more “reliable” and more accurately represent the impact of various operational factors (loads) on the durability of the bearings under test.

This article discusses a study of driver behavior in a simulated pre-crash situation. The tests were performed on a track and aimed at determining the time of the driver response to a pedestrian intruding from the left or the right. A specially developed test stand with pedestrian mockups was used. The values of the brake reaction time and the steering reaction time obtained for 30 drivers were considered in relation to the time to collision (TTC). The analysis involved determining the linear regression equations for the mean, the standard deviation and the 0.1, 0.25, 0.75 and 0.9 quantiles, which are typical measures used by forensic automotive engineering specialists. The article also provides the ranges obtained for the brake reaction times and the steering reaction times. The experimental results show that the driver response time can be analyzed as a linear function of the TTC. The means of the driver response time determined for the two variants of the scenario tested indicate that the time of response to a pedestrian entering the path of the subject vehicle from the left is longer than that obtained when a pedestrian intrudes from the right.

The paper presents a test stand and a special control system with data acquisition for the experimental analysis of physical quantities during a vehicle crash test. The crash tests are carried out at low speed of a trolley with a dummy with various seat belts (from 2-point seat belts to multi-point seat belts). Particular elements of the test stand and the control system are characterized and the measuring apparatus is presented. The measuring apparatus allows to register and specify displacements of the parts of the dummy's body, the values of forces in the safety belts and the values of deceleration on individual parts of the dummy body. During the experimental investigations, the waveforms of forces in the 3-point hip and shoulder parts of the belt in the range of crash speed 15.54–17.48 km/h were determined. Using the approximation method, the empirical relationships between the value of crash speed and the values of forces in the seat belts were determined. The results showed that despite the low speeds, the values of forces between the dummy and the 3-point belts reach significant values of up to 5 kN with the dynamic increase rate of 30 kN/s.

This paper is devoted to modern problems of reinforcement materials used in car bumpers manufacturing and as well as safety issues. Paper discusses methods and provisions for car bumper reinforcement material., As result the fail-safe energy absorbing construction is presented and tested, made from laminates A, B and C with sandwich filling of the method vacuum bagging, which confirmed the possibility of absorbing energy (i. e. work) in the entire range from 3.858–6.680J (for a stationary barrier with an impact velocity of V = 10–15 km/h — formula 1). It was found that the destruction of sandwich laminates with sandwich fillers took place by cutting the interface and the resin layer between the carbon cloth layer and the glass matting layer. The highest impact value was determined for laminate A at the level of 133.75 J (with Soric XF™filling), which was characterized by inter-layer cracking with plastic deformation of the core. Lower by about 65 and about 36% of the average impact strength for laminate C and B respectively compared to the average impact strength of laminate A, the of observed as a result of defects in the structure (i.e. plastic core deformation and one-sided delamination of aluminum and polypropylene respectively — PP from the components of the composites). In future using sandwich structured composites materials is very important from cost profitability from point through, testing and manufacturing, as well as composites repairs.

This paper presents an overview of research on the behaviour of drivers in simulated accident situations. The research was carried out by the authors of this work as a part of a research N N509 549 040 funded by the National Science Centre including new accident situations. The paper presents a description of the methodology and implementation of research on a track. During the tests, the simulation concerns about an accident risk situation involving pedestrians and passenger cars intruding the road area. In contrast to earlier research carried out by the authors, the scenario included the possibility of a pedestrian ‘entering’ from behind a curtain, both from the left and from the right sides of the road. This was possible thanks to a specially developed test stand. The paper analyses the values of driver’s reaction times characteristic to driver’s impact on: acceleration control pedals, service brake and steering wheel. In addition to the determination of average reaction time values and the regression line for the test group of 30 drivers, the assessment of the frequency of drivers taking individual defensive reactions was carried out. Keywords: traffic safety; collision; road accidents; regression equation; simulation. First published online:09 May 2014

Examining the competitiveness of public transport plays an important role because through public transport, the transport of passengers to schools, public healthcare establishments and work is ensured. In addition, transportation for vulnerable groups of passengers (students, seniors) is provided. On the other hand, public transport constitutes a financial burden on public budgets. The aim of this paper is to point out that public transport does not have an equal status in the transport market within the European Union. In the states of Central and Eastern Europe, public transport had a dominant position in the transport market in the 90s. Nowadays, the market share is declining, particularly in the bus transport, with the rising costs for public budgets regarding an increase in individual motoring. The aim of this paper is to highlight the possibilities of increasing the competitiveness of public transport by integrating different components of public transport. Another aim is to define the possibilities of financing public transport., Agentura na podporu vyskumu a vyvoja [SK - PL - 2015 - 0019]

The article presents pre-accident simulation tests conducted on a car track and in a simulator. The aim of the tests was to verify the correctness of a driver model worked out for such a type of analysis and the identification of its parameters. The article shows the comparison of parameters characteristic for driver behaviour in both testing environments. As the driver may have chosen the manoeuvre to defend – to brake or (and) to avoid an obstacle, the frequency of choosing the above mentioned manoeuvres has been compared in each testing environment. The comparison of driver reaction time was carried out during braking as well as turning. Correlation coefficients between average reaction time were determined. The comparison of a manoeuvre realization method has been conducted. As a numerical measure of the manoeuvre realization method, the parameters of a mathematical driver model were taken into account. The correlation analysis of model parameters was realized on the example of selected drivers.

Artykuł odnosi się do aktualnej problematyki komfortu podróżowania pojazdami samochodowymi. W pierwszej części opisano przeprowadzony eksperyment, zwracając szczególną uwagę na system pomiarowy wykorzystywany do badania rozkładu nacisków na siedzisko i oparcie fotela samochodowego. Omówiono budowę tego systemu oraz możliwości wykorzystania, podając podstawowe parametry jego pracy. W części drugiej przedstawiono analizę wyników przeprowadzonych badań eksperymentalnych ze szczególnym uwzględnieniem zależności między wybranymi wielkościami charakteryzującymi rozkład nacisków na siedzisko fotela a podstawowymi parametrami antropometrycznymi ciała człowieka.

This paper provides an overview of the research into the driver behaviour in simulated near collision situations. The aim of such investigations is to determine various parameters characterising the driver performance, e.g. driver response time. The driver response time is a very important parameter used, for example, to analyse road accidents. The results presented in this paper come from a study performed for two different emergency traffic situations using some predefined procedures (scenarios). The tests included situations in which a person driving a subject vehicle on a test track was to respond to obstacle mock-ups on a conflicting path (intrusion of a pedestrian from the left or from the right and intrusion of a vehicle from the right). The test data was used to determine the parameters describing the driver behaviour, i.e. the braking response time (braking manoeuvre), the steering response time (steering manoeuvre) and the intensity of the two manoeuvres. This paper compares the values of the driver response time for two scenarios, each with two variants. The average values of the braking response time and the steering response time were determined on a closed track in relation to the Time-To-Collision (TTC) in the range 0,6÷3s, characterising a near collision situation. Another parameter describing the driver behaviour discussed in this paper is the intensity of an avoidance manoeuvre. In the case of braking, the relative brake pedal displacement was analysed, while in the steering manoeuvre, the steering angle was taken into account. The average values of the braking displacement and the steering angle were presented in the function of the TTC. This paper looks at the relationship between the intensity of the driver response (braking, steering), the driver response time and the TTC.

The study presents a brief description of driver models found in the literature. Despite the large number of models, in the case of pre-accident situations the existing driver models cannot be successfully used to reconstruct driver behaviour. A driver model adequate to this type of situation has been proposed. The scenario of a pre-accident situation has been described briefly. The article aims to present the results of identification of the driver model parameters on the basis of the results of track tests. An analysis of the obtained characteristics of the turning angle and deceleration has been made. The drivers studied have been divided into groups according to similar types of reactions. The identification has been conducted for the pre-defined four driver groups. Values and reaction time linear regression equations have been specified for braking and wheel turns on the track. The results of identification of the remaining model parameters on the basis of test results have been presented.

Some aspects of marine electric power plants load registration and identification have been presented. Methods of operating data collecting about marine electric power plant loads have been shown based on an example of three vessels - a chemical tanker, a container ship and a tanker. Power plants of these vessels have been described. Examples of collected operating data were presented. Range of marine electric power plant load identification research has been characterized, which presented in the paper results are a part of.

The number of alternatively powered vehicles in Poland and EU is growing steadily. Different type of vehicle drive trains determine variations in their performances from economical and environmental technological aspects. The aim of this paper was to investigate the cost efficiency and environmental aspects of midsize passenger cars equipped with different drive train technologies: conventional, hybrid, electric and LPG fueled engine. To this purpose, the Total Cost of Ownership (TCO) method was used. Calculations were carried out by AFLEET Tool. The results show that the LPG fueled car has the lowest TCO, while the cars equipped with electric drivetrain indicate the highest TCO. However the electric car recorded the lowest cost of air pollutant emissions and externalities costs.