At the microeconomic level (the importance of transportation for specific parts of the economy) transportation is linked to producer, consumer and production costs. In many developed countries, transportation accounts for between 6% and 12% of the GDP. At the macroeconomic level (the importance of transportation for a whole economy), transportation and the mobility it confers are linked to a level of output, employment and income within a national economy. The outcome is commonly a more efficient division of production by an exploitation of geographical comparative advantages, as well as the means to develop economies of scale and scope. It is acknowledged that economic growth is increasingly linked with transport developments, namely infrastructures but also managerial expertise is crucial for logistics Transportation links together the factors of production in a complex web of relationships between producers and consumers. The importance of specific transport activities and infrastructure can thus be assessed for each sector of the economy. The productivity of space, capital and labor is thus enhanced with the efficiency of distribution and personal mobility. Transportation accounts on average between 10% and 15% of household expenditures while it accounts for around 4% of the costs of each unit of output in manufacturing, but this figure varies greatly according to sub sectors.