Source: Adapted from U. Blum and L. Dudley (2001) Report of the 109 round table on transport economics, Transport and Economic Development, European Conference of Transport Ministers.
- Centralized. One center has privileged accessibility and thus represents the dominant element of the network and the spatial structure it supports.
- Decentralized. Although the center is still the point of highest accessibility, the network is structured so that sub-centers have also significant levels of accessibility.
- Distributed. No center has a level of accessibility significantly different from the others.