How to Translate Economic Activity into Freight Transportation?
Stephan Mueller, DLR
We developed an economic indicator with which the interdependency between 59 business sectors and the amount of 24 kinds of transported goods can be shown. This enables to explain over 75% of the amount of the transported goods by economic activity.
Economic activities imply freight transportation. However the major question is: how much freight transportation is generated by which activities? In some analysis the relationship between GDP and mileage or transport intensity is evaluated. There are different views on whether such a coupling of these values though is justified and needed or not.
In this paper the relationship between the amount of 24 kinds of goods transported and economic activities by business sector is investigated.
Under the use of historical EUROSTAT supply-use tables for Germany the connection of each of 59 business sectors (NACE classified) to each of 59 products (CPA classified) is used to calculate a contribution of business class to ether provide a product or to use a product. This information and the GDP are connected to an indicator per CPA product. After the reference of 59 CPA products to 24 NSTR classified goods, the two possible indicators are built. The first is based on use tables and the second is based on supply tables. Both indicators, which are provided for each of 24 kinds of goods, are set in relation to the amount of transported goods. We conducted different tests of relationships between the economic indicator and transported tons. The results are shown and discussed. As the result of the tests we see a different interdependency between the both possible indicators and the transported goods. In the most cases a derived R² indicates a very strong interdependency between the economic indicator and the transported tons. 79% of the amount of transported tons of Germany, distinct into 24 kinds of goods, can be explained by the developed economic indicator. For the left 21% a weak or no interdependency could be found. We can state, the developed indicator is suited to translate economic activity into freight transportation.
On the one hand the findings contribute to the coupling/decoupling discussion. This is achieved by the discussion of the results. On the other hand we have a look on our results from modeling perspective. We discuss a methodology how the empirical findings could be used in freight generation approaches.
Association for European Transport