The study discussed in the paper consisted in testing the impact of surface layer parameters on wear intensity of friction pair components. The study was conducted having taken additional operational factors into consideration, namely the friction conditions (presence of lubricant) and the value of loads affecting the contact zone of the samples being tested. The study constituted laboratory tests of wear and were conducted by means of a T-01M type laboratory test stand used to experimentally analyse frictional cooperation of various materials used in structural components of motor vehicles. The friction pairs examined were previously operating in a pin-on-disk system under various conditions. The materials of the friction pairs tested at the stand were subjected to heat treatment and chemical processing in order to attain specific parameters of their surface layers. The studies conducted enabled determination of the abrasive wear values for the material samples tested having entailed the surface layer parameters and the factors related to operation of actual structural components used in automotive engineering. An additional advantage of the studies conducted was the possibility to establish actual coefficients of friction occurring in specific friction pairs. Establishing the actual values of friction coefficients for the materials of friction pairs under specific conditions and having taken the impact of the surface layer parameters into consideration enabled identification of the reasons for excessive surface wear. Hence a reference can be made between the stationary tests undertaken and actual components cooperating with one another in kinematic pairs of machines. The utilitarian premise resulting from the studies conducted is the necessity of paying particular attention to surface layer parameters while designing friction pairs for machines.

Car-sharing services are developing at an ever-increasing pace. Taking into account the reduction of carbon dioxide emissions and pursuit of the sustainable development of transport, implementing electric cars in car-sharing fleets is being proposed. On the one hand, these types of vehicles are referred to as emission-free, but on the other hand, their environmental friendliness is questionable due to the emission of carbon dioxide during the production of energy to power them. Although many scientific papers are devoted to the issue of reducing emissions through car sharing, there is a research gap concerning the real production of carbon dioxide by car-sharing vehicles during car-sharing trips. To fill this research gap, the objective of the article was to analyze the actual level of carbon dioxide emissions from combustion and electric vehicles from car-sharing systems produced when renting rides. The test results showed that the electric car turned out to be significantly less emitting. The use of electric vehicles in car-sharing fleets can reduce carbon dioxide emissions from 14% to 65% compared to using cars with internal combustion engines. However, the key role during car-sharing trips is played by the driving style of the drivers, which has been omitted from the literature to date. This should be properly regulated by service providers and focus on the proper use of energy from electric vehicle batteries, especially at low temperatures. The article provides support for operators planning to modernize their fleet of vehicles and fills the research gap concerning car-sharing emissions.

The paper provides an analysis of the reasons for excessive wear of the camshafts system components based on models developed to describe the impact of selected material, technological and operational factors. The subject of the research was wear of camshaft cams studied in accordance with results of operation tests. Based on the said tests, the dependence of wear intensity of cams from their angular position was established. The respective calculation results enabled the function of cam fallibility to be determined.

Scooter-sharing services, that is, short-term rental of electric scooters, have been gaining popularity among last-mile transport solutions in recent years, winning both their supporters and opponents. Recognizing the different approaches of societies to scooters in the world, the objective of this work was to determine the perception of scooter-sharing services in Poland, that is, the fifth largest European market in terms of micromobility. The study was based on survey data conducted using the CAWI method among the points of active users of scooter-sharing systems. The article presents the results regarding the perception of electric scooters in terms of safety, use, operation, education, and elements of communication behavior. The results indicate that the respondents perceive the Polish market of sharing electric scooters well. They believe that riding a scooter is safe (despite pointing out numerous technical faults that may indicate insufficient technical knowledge about what they can mean for users), and they are against mobility hubs and disrupting free systems. Interestingly, respondents emphasize the need to modernize the regulations, the need for penalties for damage to vehicles, and the need to reduce fees. The results provide valuable clues on how to manage the new electric mobility. They also indicate a different approach of Polish users to the issue of perceiving scooters in relation to other European societies (such as France or Denmark), which is a valuable clue for modeling transport behavior.