Knowledge creation in German agglomerations and accessibility - An approach involving non-physical connectivity

Knowledge production is a complex process in which implicit and explicit knowledge are interwoven. Therefore, knowledge-intensive firms require access to information and the ability to acquire experienced-based knowledge through face-to-face contacts. Network economies and agglomeration economies form a strong theoretical background which explains the externalities within knowledge production. Although relations between networks of cities and agglomeration effects are widely discussed, physical infrastructure and spatial accessibility are still not adequately integrated into the concept of externalities within knowledge production. Nevertheless, physical interaction fosters knowledge creation by making labour forces, greater market areas and remote locations more accessible. This paper introduces a combined framework of physical and non-physical accessibility. Interaction between firms - connectivity - is calculated using the Interlocking Network Model. Physical accessibility is defined by the potential to reach as much of the population as possible within a certain area by air, rail and road transportation. Thus, we quantitatively assess the interrelatedness of modes of transport and the non-physical connectivity of firms. This quantitative framework shows that physical infrastructure, spatial accessibility and the ability of firms to form networks are mutually reinforcing. First results indicate that on the regional scale, access by rail and road are far more important than air access, which in turn is the dominant mode of access for business activities on the global scale. Nevertheless, when taking account of the impact on regional added value, critical mass of population and employment outweighs accessibility and connectivity. (C) 2012 Published by Elsevier Ltd.