Austria consists of nine states; The capitals of eight states are centres of metropolitan regions. The most significant is the city of Vienna which is both one of the states and the federal capital and as an urban area has a population roughly equal to that of the seven other capitals and their catchment areas. In general, cities and city regions in Austria, as in most European countries, are where population and jobs concentrate. A dominant feature of spatial development in these regions, as well as in smaller cities, has been the process of suburbanization which set in at the beginning of the 1970s. As in all European cities, the spatial expansion of cities occurs along the main transportation axes. Vienna has grown mainly southward since the beginning of the 1970s. Vienna as potential transportation hub for eastern and western Europe is increasingly being confronted with traffic problems.