The paper investigates the peculiarities of polycentric urban regions (PURs) in generating agglomeration economies, namely, the question of how urbanisation externalities – size, density and diversity – take effect in German PURs and influence the growth of metropolitan functions from 1995 to 2017. The metropolitan growth of PURs is compared with that of urban regions showing a dominant core. We use our findings to address questions about the forces of urbanization externalities on a regional scale. Finally, we outline what we see as emergent research topics in the interplay between metropolization and the development of PURs.

Rural areas in Europe have been undergoing structural change for years, resulting in strong functional differentiation and fragmentation into prosperous and structurally weak areas. Rural areas are as diverse as the challenges they face. Not only various megatrends but also social, economic, technological, ecological, and political trends influence and shape the development of rural areas. In order to understand the problems and causes of the current development of rural areas, this paper provides a differentiated trend analysis for rural areas at the European level. A content analysis of more than 70 EU-funded project reports on rural areas and rural development is carried out. The aim is to identify trends and their drivers over the last decade and to summarize opportunities and challenges for successful rural regeneration. These external and overarching trends, particularly in the context of a sustainable transition, renewable energies, the emergence of new technologies and growing awareness of environmental impacts, offer rural areas more opportunities than ever before. The interplay between external incentives (e.g., European Union policies) and endogenous regional development (e.g., local actors) is crucial for the successful exploitation of these opportunities for rural regeneration.

This paper contributes to the discussion about the driving forces behind the polycentric restructuring of urban regions involving a centripetal process of metropolization and a centrifugal process leading to a regionalization of cities. Using the Frankfurt/Rhine-Main urban region in Germany as an example, it analyzes how these processes are manifested in the regional spatial structure. Two different empirical explorations are applied to reveal the spatial distribution and clustering of (1) knowledge-based industry (KBI) firms on a locational scale and (2) the sectoral specializations of and complementarities between the identified clusters. On the one hand, the identified traditional and new KBI clusters mirror the region’s traditional polycentric structure; on the other, the Frankfurt central business district stands out as the definite hotspot for KBI activities within the region. Thus, metropolization processes turn out to be the dominant driver of urban restructuring. Regarding the latter, the analysis shows that new KBI clusters frequently demonstrate strong monofunctional specialization and tend to complement and relieve traditional central business districts with regard to specific types of KBI activities, particularly in high-technology manufacturing and related high-technology knowledge-intensive services.

The newest transformation of city regions is characterized by both the emerging postsuburban development in the urban periphery and the restructuring of the city. New economic cores (conceptualized as concentrations of employment or enterprises) are emerging around the traditional central district of the city and in postsuburbia together with new city-regional relations based on the division of labor. For the case of the city regions of North-Rhine Westphalia, this article examines this transformation using different approaches. We proceed from the assumption that the new economic cores within the city regions of North Rhine-Westphalia tend to be more autonomously in their function and range of responsibilities to traditional and new cores of the central city and that new relations between the cores exist at different scales.