Sustainable Urban Transport Systems: An Expert-based Strategic Scenario Approach

Abstract

Current trends in transport indicate that the system is moving away from sustainability and that major changes are necessary to make the transport system more compatible with environmental sustainability. Main problems may occur in urban transport, where not many promising solutions are expected, while the problems are severe. In view of the great number of uncertainties, we will in our paper resort to the use of scenarios. We will address in particular expert scenarios, concerned with a sustainable transport system, by applying the recently developed spider model. Based on a set of distinct characteristics, represented in eight axes in the spatial, institutional, economic and social-psychological field, an evaluation framework is constructed which visualises the driving forces that largely influence the future of the urban transport system. Next, expected and desired scenarios are constructed on the basis of information obtained from a survey among Dutch transport experts (both average scenarios and scenarios reflecting segments of respondents). The expected scenarios show that many current trends will continue, while the transport system is largely the same as the current one. The desired scenarios on the other hand, suggest the emergence and the need for a more collective system, in which also many new modes are operating. In the paper the resulting urban transport systems are also discussed. By calculating the CO2 emissions in the average expected and desired scenario, we can test the fulfilment of environmental quality norms. It appears that the expected scenario does not lead to a significant reduction of those emissions; the desired scenario however, may lead to a large scale reduction of the emissions. The conclusion is that the differences in expert opinion are small and that a sustainable (urban) transport system is still far away in the future, although the compact city concept may perhaps offer a promising perspective.