The knowledge about the volume and structure of the transport demand and the possibility of good forecasting represents one of the basic assumptions for successful implementation of the transport policy measures. Studying the variation of the basic macroeconomic indicators and the level of mobility is one of the steps in this direction. The paper analyses the interrelations of the movements of the basic economic indicators and the usage of passenger cars in the area of the Primorje-Gorski Kotar County (especially the city of Rijeka). The study results can be used as a signpost to traffic planners in preparing the traffic plans, as well as to the executive authorities while planning the development of their region i.e. introducing of traffic measures in local and regional environments.

Functional reciprocity of all transport sectors with their infrastructure support is most evident in ports. The port of Split, integrated in Split’s traffic intersection, is a striking example of uniqueness of Split-Dalmatia County as a traffic and economic centre of Central Dalmatia. The development of City’s harbour for passenger traffic and the North Port for cargo traffic has determined already set constellation of relations of maritime, road and rail traffic, and their mutual interference. The road transport and activities with regard to hinterland services generate economic development in which Split is no exception. This estimate is based on changes that can be expected in terms of redistribution of traffic flow in the central and southern Adriatic and the greater role of road transport, with Split having an increasingly important role.

In the context of the construction of road infrastructure facilities, there is no doubt that the construction of new roads leads to an increase in the quality of transport services. A new road fosters the development of settlements through which it passes, and indirect benefits are achieved through new investments. Cost-benefit analysis (CBA) as a method involves consideration of a project’s financial returns, and most data on project costs and benefits are obtained through a relatively detailed financial analysis. Any independent variable reflected in the change results in a set share in project analysis; it is a critical variable and must be evaluated as reliably as possible. The implementation of a historical capital project in the Republic of Croatia has been highlighted in this paper – the construction of the Pelješac Bridge. Based on the transport criterion, the research has shown significant advantages achieved by bridge construction in the surrounding and wider area. The positive effects of demographic, economic, and social parameters are multiplying. The economic effects of bridge construction are highly favourable since, on the one hand, they are expressed as benefits in terms of savings on the costs of all activities from primary to quintary. On the other hand, they represent multiplications regarding the use and revitalisation of employment and natural resources. In accordance with the expected faster economic growth, the offer structure will cause a change in the relations within service activities in the direction of strengthening investments, intellectual services, tourism with all of its accompanying activities, etc. In the case considered, non-measurable benefits have not been quantified, although, independently from the CBA, their feasibility is fundamental. Nota bene, this primarily refers to the political component in strategic decision-making, such as the integration of regions, i.e., the achievement of the state territory integrity.