The study presents an analysis of the impact produced by the construction and modernization of road connections on the improvement and development of the port of Rijeka container terminal and on the growth of its competitiveness on the northern Adriatic traffic route. The paper focuses on the smoothing technique implementation as a quantitative prognostic method for road traffic. Considering the importance of container traffic within the total freight traffic in the port of Rijeka, prognostics is presented for lorry traffic on State road D – 404, which connects the container terminal of Brajdica to the expressway network to the hinterland. Thereby, the potential substratum gravitating to the container terminal and to the pertaining traffic route has been evaluated. Following description of the geographical, traffic-related and logistic situation of the port of Rijeka, the paper continues with technical and technological features of the container terminal of Brajdica and, in addition, with the significance of State road D – 404 for development of the container terminal of Brajdica and an analysis of lorry traffic trends on State road D – 404. Whereas there are confirmed assertions that there are significant differences found quite often between projected values and those ones actually obtained, the expected traffic trend values obtained by applying the smoothing technique using the moving averages method for 2017 have been assessed as satisfactory.