The importance of decoupling between freight transport and economic growth
In France and Europe, mobility and economic activity have developed with the same growth rate for several decades. This trend has to be prolonged with short – medium terms. The correlation observed between transport demand, in particular of goods, and economic growth throws light on the concepts of coupling / uncoupling which have been proposed in literature for a few years. In September 2001, the decoupling notion leaves the narrow world of the economists of transport where it had appeared a few years earlier, to be revealed with a widened public, with the favour of the publication of the European Commission’s white paper « European transport policy for 2010: time to decide ». Here, the coupling means that freight transport demand is correlated with economic growth. This perception permits to analyse underlying freight transport logics and to suggest different means for reducing negative externalities. The growth of freight transport demand, usually expressed in ton kilometres, is more easily explained by the rise of the consumption of physical distances than by transported tonnes. The spatial dimension is thus in the centre of our problems. In fact, freight transport demand is function of distances, themselves defined by the modes of interaction between manufacturing units. The approach of decoupling is based on the links between industrial and logistic organisations, location of activities and planning of freight transport systems. The hypothetical close link between industrial and spatial organisations and supply chain management has been confirmed by several scientific works (David Banister, Peter Nijkamp, Dominic Stead, Roger Vickerman). This validation rests on the analysis of industry location drivers. We can then explain the logistic organisations that govern their interactions. The aim of this research is to improve the sustainable mobility reflexion from current behaviour of freight mobility and their determinants. How is explained the trend and regular lengthening distances covered, the higher frequency of forwardings? How is explained the continuous and persistent widening of surfaces of provisioning and distribution? Several scientists defend the thesis which spatial spreading out of industrial units permits the reduction of production costs, scope economy and the improvement of wellbeing. Our work is focused on the variable “distance” like a component of the overall consumption of transport. So, we are interested in the capacity of industrial and distribution organisations to adopt another spatial behaviour. The aim is to reduce the consumption of physical distances and/or to improve the transfer of merchandises from road to other means of transport like rail, inland waterways or short sea shipping. This approach is deliberately registered in the field of economic geography, then complementary of the economic entry of the thesis of decoupling.