Population evolution after residence in the urban axis Bistrița-Beclean -Năsăud-Sângeorz-Băi in the period 1992-2000-2010-2020-2023 : Evolution of population by residence in the centre of the urban axis in Bistrița-Năsăud county, Bistrița according to age groups in the period 1992-2000-2010-2020-2023

Inter-urban flows at the level of the geographical axis from internal migration play a crucial role in the evolution of the city system at the national scale, and their analysis is fundamental for understanding the temporal and spatial evolution of cities. Specifically, the structure of internal household migration provides information about regions more likely to grow, usually accompanied by various externalities such as traffic congestion, air pollution and socio-economic inequality. Extreme flows lead to unprecedented population growth, which is usually more expansive than compact, so understanding the structure of internal migration flows at intra- and inter-city scales helps to plan for various unforeseen problems and develop mitigation strategies. This is particularly important and well-known for urbanising suburban and marginal areas with their own planning challenges and peculiarities. The dynamics of city population growth are usually studied at the city level, neglecting the intra-city spatial structure of migratory flows, an important component is the analysis of population evolution over the last thirty years.