The ESPON project 1.2.1 already developed and calculated potential accessibility indicators reflecting the situation in the year 2001. These potential accessibility indicators have been used in several ESPON projects and in a couple of European documents, among them the 3rd Cohesion Report. The main objective of this study was the update of the potential accessibility indicators for the year 2006, and to map accessibility changes since 2001. By this the present study also acts as a preparatory study for the forthcoming 4th Cohesion Report of the European Commission. The following potential accessibility indicators were updated: (i) Potential accessibility road, (ii) Potential accessibility rail.