The PhD study presented in this thesis sets out to address the question: How and why does household car ownership change over time? This question is justified on the basis that the study of car ownership has traditionally been dominated by cross-sectional, quantitative analyses. It is argued that complementary qualitative, longitudinal methods have the potential to generate explanatory insights into the underlying process through which household car ownership states arise and change over time.
Accordingly, the study employed a novel flexible two stage research design. Stage one involved 15 in-depth retrospective biographical interviews with members of zero, one and two car owning households. An inductive thematic analysis led to the development of a new dynamic framework for understanding the general process of household car ownership change. Car ownership changes are triggered by life events which alter roles/relationships, spatial contexts and lifestyle preferences. Life events lead to travel behaviour adaptation and consideration of whether the current car ownership state is satisfactory. This can create a latent propensity to change car ownership state. Given the ‘costs’ and effort involved in taking action, households tend to resist changes to their car ownership state. In some cases, action may be prompted by another external stimulus such as the receipt of a maintenance bill, or the opportunity to acquire a car from a trusted friend or family member.
The dynamic framework was tested in a neighbourhood survey involving a self-completion questionnaire and follow-up telephone call to establish a wider set of accounts of car ownership level changes. The life event driven nature of car ownership level changes is confirmed and it is found that car ownership level changes are also strongly dependent on life stage. Younger households have a tendency to increase car ownership level from zero to one or more cars as they move towards middle age. Vehicle relinquishments are more likely to occur in older age following retirement in association with health and income constraints. Over 70 percent of car ownership level changes recorded by the survey were associated with either a change in working circumstances, cohabitation, an adult joining or leaving the household, residential relocation, child birth or offspring reaching driving age. The thesis provides specific insights into the circumstances when such events are associated with a change in car ownership level.
Clark, B. Understanding how household car ownership changes over time. (Thesis). University of the West of England