The traffic policy of the European Union advocates for the redirection of the flow of goods from road traffic to inland waterways and rail traffic. The development of inland navigation and the connection of different modes of transport will influence the further inclusion of the traffic system of the Republic of Croatia in the Trans-European Transport Network (TEN-T). The expected rise in the flow of goods at the port of Rijeka and the forecasted increase in transit towards the wider European circles highlight the need for optimization of routes in the aspect of transport mode seelction according to the costs of transport and the negative environmental impact. With all this in mind, this thesis analyzes the basic rules and factors that form the transit flow of goods from the Republic of Croatia towards East Europe within the Trans-European Transport Network (TEN-T) and the possibility of redirecting intermodal goods flows from road to rail corridors and inland waterway corridor. The aim of the thesis is the development of a transport mode selection model with optimal characteristics according to the distribution of the flow of goods through the intermodal corridors. In order to achieve the stated research purposes, the main objective of the research is to create a transport mode selection model with the most favorable characteristics by using fuzzy logic. The model is applied to international traffic corridors, the Mediterranean Corridor, and the Core Network Corridor in railway traffic and inland navigation by accepting the relevant rules and criteria for forming the flow of cargo through the intermodal corridors (criteria of infrastructure, criteria of transporting resources, criteria of property characteristics, criteria of negative environmental impact and criteria of economics and organization). By taking into account the relevant criteria and variables, which unite a larger number of influential parameters, with the application of fuzzy logic to quantify expert knowledge, the value of the index of transport mode selection, the composition of the model, the selection of variables of energy efficiency, environmental pollution, transport of cargo in the return direction, and the variable of flexible business policy, or the degree of attachment to certain transport modes that have not been used before. A universal model of the mode selection model for transport has been formed in relation to railway and inland navigation waterways. The developed transport mode selection model on intermodal corridors manifests the scientifically-theoretical and applied contribution of the research since the model is applicable to any intermodal transport direction for the needs of traffic decision-making when planning and choosing the most favorable transport mode while taking into account the current criteria and constellation on the market of cargo flows.