Determining Factors in the Development of Road Freight Transport
KVEIBORG O, National Environmental Research Institute, Germany
During the last decades demand for freight transport have been growing al- most continuously. The reason for this growth is primarily the overall eco- nomic growth, but many other factors influence the growth path. Moreover, the type of economic growth pl
During the last decades demand for freight transport have been growing al- most continuously. The reason for this growth is primarily the overall eco- nomic growth, but many other factors influence the growth path. Moreover, the type of economic growth plays an important role in the development of freight transport. Growth in the public sector does not have the same impact on the demand for freight transport as growth in the construction sectors does.
But what exactly are the determinants in the development of read freight transport? To help answer this question a macroeconomic model describing the linkage between economic activity and freight transport has been devel- oped. At first hand the purpose of the model was not exactly to be able to an- swer this question, but rather to develop a model that were able to answer the questions: "What are the environmental impacts of the general economic de- velopment?" and "What are the impacts from different specific (economic) policy proposals?" Thus, the purpose of the model and the purpose of this paper seem to go hand in hand. To answer the latter questions it is necessary to find (some of) the determining factors. This paper focuses on investigating the determining factors, and less on the actual model system. However, to understand the ideas and discussions of the different elements in the paper better, the model will be described in broad terms in section 2.
As it turns out we will not really be able to answer the questions raised here. This does not mean that we are not able to - at least partly - give some insight into the complex relationship between economic development and read freight transport. By an appropriate disaggregation of the economic development we are able to describe the structural relationship, and thereby the different levels of the transport demand in different sectors. However, the changes over time in these structural relations should also be described in some way. In this re- spect the message of the paper is only partly instructive, stating elements that are only partly determinants in describing the development in read freight transport. The reason for this negative result is primarily due to the fact that the model is an aggregated model, using price variables as describing factors. Many of the structural elements are not related to the price variables in the way they are used here (or perhaps not at all related). To be able to find the real determining factors it is necessary to go even further into detail, and work at the micro level using individual transport providers (e.g. haulage contrac- tors), and the firms demanding the transport services (both the transport per- formed by the firms themselves and the purchased transport). In this respect the time period is also of some importance. Structural changes happen over a longer period and are not related to the change in differenl prices from period to pedod. Another almost equally important reason for the conclusions is the very inadequate data concerning freight transport. For the transport modes rail, air and sea transport almost none is available, whereas for road transport some data exists, but it is still very poor.
As already mentioned there are significant gains from the present model de- velopment. Some of the analyses that have been carried out can be used in future research in this field, and some of the elements in the model do give some reasoning for the actual development. Existing models describing the relationship between economic development and the development of freight transport are all inadequate in the description of some parts of the develop- ment. Most of these models assume a simple relationship between the overall development in GDP and the transport performance (tonne kilometre) without concern to the different influence from different economic sectors and types of goods. The model we have developed take the same starting point, but use the information stemming from a disaggregation on different production sec- tors and categories of goods. Hence, we obtain a detailed description of the transport performed.
In section 2 the general outline of the model is presented with a discussion of some relevant influencing factors on each level of the model. A section de- scribing the primary data used for estimations in the model follows. A few de- scriptive analyses of the data, and especially the linking factors are presented. In section 4 the general conclusions of the many estimated relations are pre- sented. In most cases these are only the simplest of the regressions we have carried out. They do, however, describe the problems we have faced in this work. In the last section of the paper we give some general comments on the use of the model, some advantages and especially disadvantages, and we give a few recommendations on how to proceed on this work.
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