The process of European integration, and particularly the enlargement of the EU, has substantial consequences for transport and the way it interacts with the rest of the economy. Transport intensity has been increasing and changing transport costs have different impacts on different sectors and regions depending on both traditional factors such as value to weight ratios and the competitive structure of industry. This paper explores some of the factors lying behind the rise in transport intensity, how it relates to trade and to changing activity patterns and the endogeneity of transport with the process of specialisation and regional concentration. This is set against the pressures arising from EU enlargement. This leads to questions concerning the sustainability of exiting transport policies which place emphasis on mobility. The paper explores the dynamics of the relationship, highlighting the way in which the modelling of the transport system needs to interact with that of the rest of the economy.