Transportation investment evaluation:Basic problems and concepts

In this paper the complexity of the world today and its consequences in science were used as starting points. Basic concepts and problems in transportation planning and in the related disciplines were considered. With the aid of systems thinking methodology, hierarchical levels for evaluation procedures and conceptual models were formed. The conceptual model of evaluation includes three steps; define impacts, inform others, and draw conclusions. With regard to conceptual models, impacts, hierarchical levels and uncertainty various evaluation methods were analyzed. Cost-benefit analysis and multi-criteria analysis are aimed at drawing conclusions. The other theoretical methods and guidelines are more comprehensive. The guidelines used in Scandinavia disregard uncertainty and include only a part of the possible impacts. The guidelines used in the U.K. have much in common with the newest theoretical methods. The recent development in the guidelines used by road authorities shows a consideration for the differences in the goals between the national and local levels. No evaluation method can show the best solution. They can only aid in the information and decision processes. Strictly used evaluation procedures may mean unfair influencing of outside participants. Future research would probably be more useful when concentrated on impact definitions and consideration of hierarchical levels instead of further elaborations of the conclusion stage