The share of start-up wear in total wear of an automobile engine is large, and in the analysed case it exceeded 40%. The amount of start-up wear of engine elements strongly depends on start-up temperature: the lower temperature, the larger wear. Hence the particular significance of so-called cold start-ups, which most often are first starts of an engine on a given day. The temperature of the first start-up in ungaraged vehicles is the same as the temperature of the surroundings, and it depends on the season. This article analyses changes in mean intensity of wear of a truck engine cylinder liner associated with different temperatures of first start-up in different seasons. In the analysed case, the intensity of wear in winter was 16% higher than in the summer. Also discussed are the possible consequences of the above changes for wear intensities determined in measurements

The interviews conducted with the drivers and analysis of possible sources of collisions and accidents show that at night, on unlit areas, truck drivers towing trailers or semitrailers have insufficient observation area around the vehicle. This insufficient amount of information reaching the driver is the cause of many accidents and collisions. The article describes the risks associated with the lack of visibility of the area around the semitrailer and presents solutions allowing to reduce the identified risks. The solution is to use additional contour lights, and lights illuminating the road in the area, which is run over by the semi-trailer wheels. Based on the simulation studies and laboratory studies of light distribution, the appropriate lamps have been selected and installed on the trailer. Then the field tests were carried out on the real object, which confirmed the usefulness of the proposed lamps and showed that it is possible to support the vehicle driver in obtaining information from areas previously invisible