Differences and similarities in the expansion of suburban built-up areas around the different city regions of three Central European countries

Examining the urban sprawl around middle-size cities in Hungary and Central Europe, the rural change and suburbanization can be characterized by residential out-migration from cities and at the same time by immigration from the rural areas. These processes have intensified in the former socialist countries after the 2000s and a number of problems have not been addressed, which have become apparent during the eighties and nineties in Western countries. A fast urban sprawl took place with a low level of special control and planning but under the pressure of economic and financial development. The rate of spatial growth often exceeds the rate of population growth, it even occurs in the absence of population growth. In Central European countries, the main destination for migration is the capital cities and their suburbs, therefore suburbanisation studies focus on these areas. However, our aim is to focus on regional centres and their agglomerations, comparing them to capital cities and rural areas. The most dynamic and new urbanisation processes are taking place in urban agglomerations. The phenomena observed in these countries, especially in regional cities, have no historical precedent, but are a novelty from both a social and an economic point of view. The paper concentrates on the urbanisation tendencies of three post-socialist countries - Slovakia, Hungary and Romania -, on the basis of the expansion of the impervious surfaces and the change in the number of the population. For each country, capital cities, regional centre areas and more remote rural areas are analysed separately. The goal of the paper is to reveal the differences among the three countries in the density of population in areas affected differently by urbanisation. This issue is examined in all three countries that have gone through similar economic and political transitions, together with the differences caused by the diverse historical, geographical, and settlement hierarchy endowments at the time of the development and migration boom following the world economic crisis of 2008. It is hard to detect what role the economic crisis played in this, but it is certain that the crisis led to a significant downturn, which was followed by development in quite different directions in the cities, urban fringes, and rural areas in the surveyed countries. The flow into cities seems to have accelerated, mainly in the case of capital city regions and the edges of regional centres. Besides population movements, the expansion of built-up areas is much faster, especially in less densely populated areas where the dynamism of these was outstandingly high between 2012 and 2018. This may have several negative consequences. In areas in the vicinity of urban zones of such high population density may emerge, which may lead to societal problems later.