Analysis of external factors affecting transport process safety

Transportation systems belong to the category of systems whose operation safety depends on many factors including: technical state of transport means, behavior of people involved in the system operation and maintenance and its environment, and finally the environmental factors. The system environment is referred to as all the elements, which, though not belonging to the system, are closely related to it. The environment, which is of interest for the authors of this paper, is the road infrastructure and atmospheric conditions. Construction solutions of the infrastructure, the road surface type and condition, temperature, visibility, precipitations, and time of day are referred to as external factors whose impact involves changes in safety of the transportation system operation. The impact of external factors can be in different forms and can affect the transport means as well as people involved in the system operation, especially the drivers. The literature provides a concept of excessive sense of a driver’s safety, which can be caused by good road conditions, dry and good road surface, etc. This is of particular importance in case of public transportation systems providing transport services on the territory of a town where the effects of external factors account for nearly 44% of adverse events causes. This study deals with identification of these factors and assessment of their influence on the analysed transportation system safety.