Abstract : Transport, being an indispensable support for economic and social interaction, has a major role to play in the structuring of urban regions all over Europe. Accessibility is one of the basic factors of competitiveness, but also of access to services, while at the same time it is one of the major sources of pollution and of energy consumption. Accessibility is one of the major factors of city development. Accessibility constitutes a necessary condition for the economic and spatial development, and accessibility is one of the key sectors where public action plays a major role in infrastructure as well as in service provision in interaction with the transport operators. Developing tools that are able to assess the quality of the accessibility is then a major stake for decision help dedicated to urban stakeholders. In addition accessibility represents a necessary condition for the development of exchanges between cities and between cities and their hinterlands. Measuring accessibility constitutes a step in the study and the identification the potential for development of cities; it also allows for identifying those links that already permit the development of cooperation between cities and those links that lack the minimum service provision to support polycentric development. The analysis of transport services across Europe will give much importance to the air mode as the privileged long distance mean to link cities. If we consider that the intensity of the links decreases with distance, we observe that proximity OD pairs are of major importance to city development, and to polycentric organisation. On these shorter distance high-speed rail, and to a lesser extent conventional rail, can play a prominent role.