Traffic plays an important role in the daily life of people and in the organization of their living space, because people travel from one place to another every day due to various life needs, activities and services. This need particularly became important with industrialization, which stimulated the movement of industrial workers from the countryside to the city, as well as the development of the city and the expansion of its functions in rural space around it. The aim of this paper is to investigate the role of transport in the formation of the Urban Agglomeration of Zagreb (UAZ), so this agglomeration is suitable for such research because the arrival of the railway in 1862 stimulated the rapid development of Zagreb, and the expansion of its functions into its surroundings. In order to determine the causes and circumstances that led to the formation of these ties, their historical-geographical development was analysed. Based on the gravitational area of Zagreb, the possibilities of even demographic and socioeconomic development within Central Croatia were determined, as well as the problems that make this impossible. In order to investigate the aforementioned possibilities and problems more easily, it was determined is UAZ going through urbanization, suburbanization, counter-urbanization or reurbanization. Based on the quality of transport connections, the possibilities of population movement within the agglomeration were investigated. The research included 30 municipalities under the borders of UAZ in the "Strategy for the Development of the Urban Agglomeration of Zagreb for the Period Until 2020" (2017), between 1850 and 2022 by secondary data analysis and synthesis.