Future urban sustainable mobility - Implementing and understanding the impacts of policies designed to reduce private automobile usage

Abstract

The historically recent growth in interest in policies designed to reduce private automobile usage, policies coming under the rubric of travel demand management (TDM), is offset by a paucity of systematic research concerning the procedures by which to define and implement such TDM policies or measures, the consequences of such TDM measures and the nature of the ensuing adaptation process occurring upon implementation of any TDM measure. The present thesis’ conceptual framework for understanding the effects of TDM measures extends and complements previous work in the transportation literature by drawing on psychological theories of goal setting and adaptation. The framework views travel choices as being determined by bundles of attributes characterising travel options and by goals and implementation intentions formed over time in response to evaluations of the psychological, generalised costs of current travel. Study I utilised travel diary data to demonstrate that the specific instantiation of a TDM measure (i.e., its spatial and temporal parameters) is critical to the understanding of the ways in which the travel options of various sociodemographic groups for various trip purposes are altered. Taken together, Studies II and III, which utilised focus groups and Internet-based surveys, revealed that people tend to minimise any reductions to their car use wherever possible, with any reductions being achieved in a manner minimising the psychological costs that do occur. That is, evidence consistent with a cost-minimisation principle of adaptation was obtained. Study IV demonstrated that the implementation of long-term TDM measures, assumed to have a bearing on the mobility options and adaptation alternatives available to people, is well suited to participatory planning methods involving the evaluation of future scenarios that are the result of careful analysis of present trends and plausible future developments. The methods examined are a means by which to better project potential and expected futures, and a means by which to systematically understand and communicate preferences for these futures, with reference to both scientific and non-scientific knowledge bases. In conclusion, this research presents some tentative, initial steps towards the greater theoretical understanding of the nature of TDM measures, the changes they effect, the citizens they affect and the principles underscoring citizens’ adaptation process to such TDM measures, with clear and definite practical implications concerning which things to do, why and how.