En model for godstransportens udvikling - DCE - Nationalt Center for ...

Summary
This report describes the results of a large project conducted in a corporation
between Statistics Denmark and the Danish National Environmental
Research Institute. The main objective of the project has
been to analyse the possibilities of prescribing the development in the
Danish freight transport in a more appropriate and precise way than
it is done by existing models. The Danish Transport Council, the
Ministry of Transport and the Energy Research Programme 1997
have financed the project.
A secondary objective of the project was to develop a model based on
the findings of the analysis. The intention was to be able to describe
all areas of freight transport. The analysis has proven it impossible to
improve the existing calculations in some areas of transport. Hence,
the project has been narrowed down to focus exclusively on road
freight transport.
The developed model distinguishes itself from existing models by a
much higher level of detail in the calculations. This enables the model
to describe the structural relations between transport and economic
activity, which has previously been subsumed in the aggregate calculations
of existing models.
The work carried out in the process of developing a model for the
freight transport has encountered many difficulties. The findings described
in this report are merely one step towards a better understanding
of the relation between economic development and transport.
The descriptions on the following pages will describe some of
the difficulties we have had in achieving an appropriate statistical
description of the different linkages. Furthermore, the calculations
carried out with the model point at other unsolved problems. There is
an indication that the model tends to overestimate the developments
in freight transport. In this respect, the very disaggregate calculations
of the model can be seen as both an advantage and as a disadvantage
because each extra calculation gives rise to further uncertainties in the
overall result.
Even though we have had great difficulties finding adequate descriptions
of the development in the factors in the model, it is a good
starting point when consequences of the described type are to be
analysed.
The developed model will give better and more sophisticated information
on the consequences for road freight transport from economic
developments compared to the existing possibilities. The improvements
compared to existing models do not stem from very detailed
and complex econometric relations, but stem from the detailed and
structured disaggregation of the production sectors. However, it is
not satisfactory not to be able to describe the underlying reasons for
the different structural developments described by the technological
trends. With the data at hand we do not think it possible to develop
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