Until today, most traffic forecasting and appraisal methods assume an increasing transport demand and capacity in the future which goes hand-in-hand with economical and population growth. However, recent developments in many countries, for example Germany, challenge this assumption by shrinking population and economic activities in several urban regions. Research on the costs and benefits of the transport infrastructure under shrinkage conditions is, yet, limited to very few studies. Still, in most policy documents a well dimensioned and developed (and so future-proofe) transport infrastructure is considered to be an important locational advantage for the economical development of a region and an important decision criteria for the residential and business location choices. However, some authors argue that in non-growing urban regions no new transport infrastructure should be constructed for limiting the future infrastructure costs and for limiting the future travel demand. The socio-economic processes in shrinking regions affect transport demand by reduced total and increased per capita traffic volumes and capacity needs, and by a changing modal split. The transport infrastructures occupancy and usage is affected by the reduced transport demand and, thus, its effectiveness is altered. The aim of this paper is to present an assessment methodology for transport infrastructure under shrinkage conditions. For that purpose we focus on the effects of population and economic shrinkage on the costs and benefits of urban transport infrastructure. We start from the commonly used cost benefit analysis. Appraising the advantages and disadvantages of this method, we extend this assessment methodology with elements from other evaluation methods and, ultimately, present a multi criteria analysis for assessing the economic effects of transport infrastructure under shrinkage conditions. First results on the application of the appraisal method on a case study will be presented. This assessment represents the first part of a to-be-developed comprehensive evaluation instrument. In a second part, cost-benefit-aspects will be compared to sustainability criteria. As a result, we will develop possible courses of action for the design of future transport infrastructures in shrinking urban regions. For the covering abstract see ITRD E137145.
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