The main objective of the present study is to assess the possible impact of the completed Via Carpatia route on changes in potential accessibility. The auxiliary objectives are: a) comparison of the effects of creating the entire route in selected regions and cities (in particular peripherally located medium-sized centres), and b) comparison of the effects of implementation of particular sections of the future undertaking. The eastern peripheries of the European Union remain, in a large part, an area with development opportunities reduced by the lagging transport infrastructure, as this is expressed by lower level of spatial accessibility indicators. The analysis here presented confirmed that the construction of the new corridors (here: Via Carpatia route) can improve this situation. However, the possible positive investment effect is selective in the territorial sense. It is also dependent on other investments, including routes having east-west and oblique orientations.