The paper gives an overview of different air pollution models in projects and studies in the field of road traffic. A brief description is given for the presented models with key elements for their application. Special emphasis in the paper is given to the application of the current model in the Republic of Srpska. Literature analysis in the field of air pollution modeling has shown that there are a large number of air pollution models. The most comprehensive model in terms of applicability and available data is the COPERT IV model, which is widely used in the European Union.

Railway level crossings represent critical points in the road traffic safety system, where serious incidents with severe consequences occur despite the presence of prescribed signaling. From 2021 to 2025, the Republic of Serbian implemented a multi-sector preventive initiative entitled ”Cautious Drivers Watch for Level Crossings”, aimed at raising awareness among road users and reducing the number of extraordinary events at railway crossings. This paper analyzes the effects of the campaign through statistical data on the number of fatalities and injuries, as well as through the results of monitoring driver and pedestrian behaviour at crossings with different levels of protection. Special emphasis is placed on the role of local communities and cooperation with institutions in identifying high-risk locations, eliminating unsafe railway crossings, and educating the public. The presented results highlight the importance of continuous communication, systemic cooperation, and consistent enforcement as prerequisites for improving safety at railway level crossings.

The efficiency of logistics processes largely depends on the selection, sizing and stacking of aggregate and transport packaging. Properly organized packaging not only protects products but also directly affects the rationalization of space, the speed of manipulation and the reduction of costs in the supply chain. This paper analyzes the way in which standards and methods of stacking packaging units can improve operational efficiency. Through a theoretical review and analysis of practical examples, the role of palletization, modularity and optimal capacity utilization in the storage and transport process is discussed. The research confirms the hypothesis that adequate stacking of aggregate and transport packaging significantly reduces logistics costs and the time required for delivery, which directly contributes to improving supply chain performance.