Where sustainable transport and social exclusion meet: households without cars and car dependence in Germany and Great Britain

The background for this thesis is the dramatic growth in travel demand that has taken place in developed countries in the last decades, and is gathering speed at the global level. This goes in hand in hand with a dramatic increase in motorisation and car use. This phenomenon is the object of Chapter 1.Increasing mobility and motorisation has raised two kinds of concerns, corresponding to two research fields. Concerns for the environmental consequences of transport are behind the concept of environmentally sustainable transport. Transport contributes to both climate change emissions and oil depletion, arguably two of the most important environmental challenges of the 21st century. However, as mobility grows, society (and urban structure) adapts itself: the result is that being able to cover great distances at sufficient speed has become paramount. In other words, mobility and accessibility have become key factors for social inclusion, resulting in new forms of social inequality and/or reinforcing existing ones. In the theoretical part of this thesis (Part I), these two fields of research are reviewed. Chapter 1 discusses the environmental consequences of increasing motorisation, as well as policies for environmentally sustainable transport. Also, different approaches to the study of increasing motorisation (car ownership modelling, the ‘travel and the built environment’ debate and the concept of car dependence) are reviewed. Chapter 2 introduces the field of transport and social exclusion research, and reviews policies to tackle transport disadvantage. Interestingly, these two fields of research have remained quite separate until very recently. Arguably, this is a problem, for at least three reasons: firstly both concerns arise from a common problem, i.e. the increasing demand for (car) travel; secondly, the leading policy concept of ‘sustainable transport’ includes both environmental and social goals (as well as economic ones); finally, literature in both fields provides numerous examples of instances where there is a trade-off or a latent tension between environmental and social goals (as discussed in Chapter 2). This in turn is arguably a strong barrier to the implementation of sustainable transport policies. At the theoretical level, the goal of this thesis is to put forward an integrated framework to conceptualise the social and environmental consequences of increasing motorisation, and their interrelationships. To do this, I use the concept of car dependence. Since it has mostly been used in studies concerned with the environmental consequences of increasing motorisation, the notion is introduced in Chapter 1. In Chapter 2, I put forward a typology of forms of car-related transport disadvantage, and illustrate how they arise from the process of increasing car dependence. In Chapter 3, I put forward an original working definition of car dependence, aimed at reconciling the two concerns and highlighting the role that the different forms of car-related transport disadvantage play in the self-reinforcing cycle of increasing motorisation. All throughout the theoretical chapters, the emphasis is on the spatial dimension of car dependence: urban structure and the built environment adapt to increasing motorisation, and this results in further motorisation, thus creating a self-reinforcing cycle with both environmental and social consequences. The research object of this thesis is households without cars. There are two main reasons for this. Firstly, it is located at the intersection of the two research fields. From an environmental perspective, carless households have been studied as examples of environmentally sustainable behaviour. Notably, existing research has sought to identify households who choose to live without cars, exploring their motivations and trying to understand how to encourage carfree living. By contrast, in transport and social exclusion research, lack of car access has been considered as the most important form of transport disadvantage in developed societies. Accordingly, studies have focused on the exclusionary consequences of living without cars. Overall, studies on environmentally sustainable transport focus on a type of carless that is quite different from that considered by research into transport and social exclusion: an inadvertent outcome of this situation is that the overall view of the sheer variety of situations that cause people to live without cars is lost. By contrast, I argue in this thesis that there is a need to focus on the composition of the carless group as a whole, and on how it varies over time and space. The empirical work illustrated in Part III of this thesis is organized around two research questions, and both deal with the composition of the carless households group. Notably, the research questions are derived from the ‘car dependence’ theoretical framework, as illustrated in Chapter 3. In a nutshell, the idea behind both research questions is that there is a relationship between the degree of car dependence of a given (local) society and the composition of the carless households group. The two research questions adopt different approaches to explore the relationship between car dependence and the composition of the carless households group. Question 1 adopts a synchronic perspective, by comparing types of area with different levels of car dependence at the same moment in time. Differences in the composition of the carless group across different types of area are explored, with reference to the following four areas: socio-demographics, reasons for not owning cars, travel behaviour and accessibility to services and opportunities. Based on the results of previous research, the different types of area are assumed to correspond to different degrees of car dependence. Question 2 adopts a diachronic perspective by comparing the composition of the carless households group at different moments in time. The assumption is that, given the continuing process of increasing motorisation, car dependence is higher at a later moment in time. In this case, only the socio-demographic composition of the carless household group has been explored. In accordance with the tradition of the Doctoral Programme in Urban and Local European Studies at the University of Milan-Bicocca, the empirical work has focused on two case studies: Germany and Great Britain. Information about the countries (with reference to transport and spatial planning policies and previous research on car ownership trends and households without cars) is provided in Part II (chapters 4 and 5). Both research questions have been explored for both case studies, and the empirical results are illustrated in Chapter 6 and Chapter 7. The research strategy adopted is quantitative secondary analysis of national travel surveys (Mobilität in Deutschland and National Travel Survey). For the synchronic analysis, I used data from the 2008 wave of MiD and a pooled sample (2002-2010) for NTS. For the diachronic analysis, I compared data from the 2002 and 2008 waves of MiD, and single waves of the continuous NTS survey over the period 2002-2010. The data analysis techniques employed include, beside descriptive analysis, (multinomial) logistic regression, cluster analysis and latent class analysis. All techniques are described in detail in Appendix A in Part V. Appendix B and C report the details of the data analysis for both case studies, as well as technical details for both national travel surveys. Part IV consists of a single concluding chapter, including two sections. Firstly, the empirical evidence for the two case studies is brought together and discussed in light of the research questions and hypotheses. Secondly, the empirical results are discussed in light of the theoretical and policy debates outlined in Part I and II. In the following, I outline the main empirical results of this thesis. - firstly, the carless households group is considerably more concentrated among marginal social groups in low density and peripheral (‘car dependent’) types of area. To put it simply, this means that the composition of the carless group is a good indicator for the level of car dependence of a local area. More formally stated, this means that the strength of the association between non-car ownership and its socio-demographic determinants increases as the degree of urbanity decreases. This is a novel conclusion, and sits alongside the results of previous research suggesting that the car is more of a necessity in low density areas - secondly, the ‘mobility gap’ and the ‘accessibility gap’ of carless households (as compared to car-owning households) increase as the degree of urbanity decreases. Also, results for the British case study suggest that carless individuals are more likely to rely on car lifts, taxis and other motorised transport modes in the most car dependent areas. However, in-depth analysis shows that all of these results are also the by-product of the varying socio-demographic composition of the carless group across different types of area - thirdly, carless households in low density areas are more likely to mention age and health-related constraints as reasons for not owning a car. Conversely, they are less likely to mention choice and lack of need. However, perhaps counterintuitively, it is carless households in compact cities who are the most likely to be carless for economic reasons These empirical results contribute to theoretical and methodological debates in both fields of research (environmentally sustainable transport and transport and social exclusion research). Notably: - by showing the variety of conditions associated with non-car ownership, I counter the assumption that lack of car access per se leads to serious transport disadvantage. While the goal of this thesis was not to identify those carless households who are transport disadvantaged, distinguishing them from those who are not, the empirical results suggest that not owning cars might result in very different forms of disadvantage, ranging from virtual immobility to reliance on others for car lifts to time poverty (as a result of lengthy commutes with alternative modes). This thesis shows that these different forms of non-car ownership are not distributed randomly, but follow a spatial pattern: therefore, it might serve as a blueprint for future studies based on ad-hoc surveys or adopting a qualitative approach - the empirical chapters bring to light the peculiar features and the complex structure of the carless households group. Indeed, this population is: concentrated among marginal social groups; concentrated in large cities and in the most densely populated areas; more concentrated among marginal social groups in suburban and rural areas and where population density is low (a novel conclusion). Arguably, this increases the risk of drawing wrong or misleading conclusions when comparing means between the car-owing and the carless population. In other words, the complex structure of the carless households group has methodological implications for future research - the empirical results about the reasons for not owning cars suggest that the emphasis of existing research on questions of choice is misplaced. The data do not show a continuum between the poles of choice and constraint, but rather the existence of ‘absolute’ constraints to car ownership (such as those related to old age and health-related mobility difficulties), on one hand, and the complex interweaving of ‘weaker’ economic constraints with choice and lack of need, on the other. Notably, one possible interpretation of the results is that low-income households have to choose between ‘two evils’: lack of car access (with possible implications in terms of reduced accessibility) and the economic stress arising from owning and running a car. Depending on the structural constraints brought about by the built environment, they end up choosing one or the other. In other words, there might be a complementary relationship between two forms of car-related transport disadvantage: car deprivation and car-related economic stress. While this hypothesis is not tested in this thesis, it is put forward for future research To sum up, with this thesis I hope to demonstrate two things. First, it is possible to conceptualize the environmental and the social consequences of transport within a single framework, and to conduct empirical studies that take into account both sides. The key link between the two concerns is the need to own and drive cars. Second, focusing on those who do not own cars is a powerful way to understand better what makes people so reluctant to give up theirs.