Road transport is one of the main sources of atmospheric pollution in urbanized areas. The volume of emissions from road transport has been increasing starting from 2013. This is mainly due to the condition of the transport infrastructure and control systems. Therefore, the development of evidence-based methods of increasing the efficiency of traffic management through the modernization of infrastructure facilities and control systems in problematic areas of the street and road network is crucial and of practical and theoretical interest. This paper analyzes problematic areas of the street and road network in a medium-sized city. The authors have made simulation models of an area of the street and road network on the basis of the discrete-event approach using a road traffic library. Measures to modernize this area are suggested. A computer experiment using a model with a changed configuration has shown that this area has a significant potential of improving traffic flow parameters and, therefore, reducing the environmental impact.