The paper discusses problems of sustainable development of transport systems with special attention paid to noise pollution and emission of harmful compounds of exhaust gases. It presents traffic flow model for a transport network, which can be applied for estimation of external costs of transport resulting from congestion and congestion-related effects like noise and harmful emission. Model includes structure of vehicle stock, segmentation of transport, characteristics of roads and elements of surroundings. It allows for computational experiments with traffic distribution into transport network and traffic management and, in consequence, estimation of environmental effects of traffic flow. Formal model was supported by numerical example for transport network of Mazowieckie voivodeship in Poland. The example is based on noise pollution and its external costs. The model was developed on the base of EMITRANSYS model for Mazowieckie in 2016.

The transport system of a Smart City consists of many subsystems; therefore, the modeling of the transportation network, which maps its structure, requires consideration of both the connections between individual subsystems and the relationships within each of them. The road and street network is one of the most important subsystems, whose main task is to ensure access to places generating travel demand in the city. Thus, its effectiveness should be at an appropriate level of quality. Connectivity is one of the most important characteristics of a road and street network. It describes how elements of that network are connected, which translates to travel times and costs. The analysis of the connectivity of the road and street network in urban areas is often conducted with the application of topological measures. In the case of a large area of the city, such analysis requires its division into smaller parts, which may affect the computational results of these measures; therefore, the main goal of the study was to present a method of performing analysis based on the computation of numerical values of selected measures of connectivity of road and street network, for a city area divided into fields of regular shape. To achieve that goal, the analyzed area was split into a regular grid. Subsequently, numerical values of the chosen measures of connectivity were calculated for each basic field, and the results allowed us to determine whether they are influenced by the method of division of the area. Obtained results showed that the size of the basic field influences the numerical values of measures of connectivity; however that influence is different for each of the selected measures.