A study of the impacts of Εgnatia odos and the vertical axes upon polycentric spatial structure in Νorthern Greece

The Egnatia Odos motorway is the basic transport and communication corridor in Northern Greece, whereas it is connected with the countries of South-East Europe through the Vertical Axes. The impacts of the system Egnatia Odos-Vertical Axes upon spatial structure consist a critical parameter regarding the potential for new spatial patterns based on connectivity, networking and polycentricity. Spatial development objectives, both at the European and national level, aim at polycentric spatial structures. Polycentricity is significant as a target-pattern of spatial development, while several studies attempt to define it quantitatively with the help of specific methods and indicators. This article proposes a methodology to assess the impacts of the system Egnatia Odos-Vertical Axes on the spatial structure of Northern Greece giving special emphasis to the question of polycentricity. The proposed methodology, based on relevant European research, is articulated upon the assumption that polycentricity is a condition that concerns, on the one hand, the size and classification of urban centres (morphological polycentricity) and, on the other, the relations between urban centres (functional polycentricity). The main finding of this paper is that, although the system Egnatia Odos-Vertical Axes cannot affect on its own the morphological polycentricity, it contributes considerably to the functional polycentricity.