Understanding Residential Relocation and Travel Behaviour: Mechanisms, Inequalities, and Implications

Abstract

Active travel, such as walking or cycling, is an effective way to incorporate physical activity into daily routines, which is beneficial for health. Research has extensively examined how features of the built environment facilitate or hinder active travel, though findings – particularly on the effect of changes in an environment on active travel - remain inconsistent. Importantly, individuals are not always located in the same environment and frequently undergo life changes that can have an independent effect on travel behaviour. Relocating home is a major life event that usually involves a significant change in the environments people are exposed to and (therefore) often leads to changes in travel behaviour. However, the exact mechanisms giving rise to these changes remain unclear. Some suggest that these changes in behaviour are driven by changes in the physical environment alone, others highlight preexisting preferences that moving enables, the influence of changes in social networks, or the disruption to routines consequent on relocation, providing an opportunity to reconsider travel choices. Partly due to its complex effect on travel behaviour, relocation is often seen as a challenge when evaluating interventions that aim to increase active travel. Alongside introducing additional confounding factors, it can result in changes in the population make-up of an area where an intervention is implemented, and alter the distance or exposure to environmental features that are being evaluated. In studies using cohort designs it can also lead to attrition. Consequently, many evaluations exclude movers from analyses or simply adjust for the occurrence of a relocation in statistical analyses. In contrast, research from geography and demography treats relocation as a key process, examining why people move, the characteristics of movers, and how their movement impacts population dynamics in origin and destination areas. Yet, these studies rarely explore specific health behaviours or the mechanisms underlying observed health differences. The aim of my interdisciplinary thesis is to integrate geographical perspectives on relocation with public health insights into promoting physical activity and active travel. This approach seeks to better understand the mechanisms behind travel behaviour changes and develop a more inclusive, whole-population understanding of how changes in the environment influence health. First, I explored the processes through which relocation leads to changes in cycling, using a novel qualitative method called theory-building process tracing to re-analyse 28 interviews conducted between 2008 and 2011 as part of the Cycling Cities and Towns (CCT) project in England. I identified three mechanisms linking relocation to changes in cycling behaviour: physical changes, social changes, and intentions. Most (male) participants reacted to physical changes in the environment. Reassessment of these changes was common among those who increased cycling but not those who reduced it. I highlighted the important role of social changes in influencing cycling behaviour post-relocation and revealed gender differences in how these social shifts influence behaviour. Second, I examined whether people who have recently moved to an area differ from longer settled residents in their health, travel behaviour, and perceptions of the environment. Using a large, representative sample from the United Kingdom Household Longitudinal Survey (UKHLS), I found that recent movers showed significantly lower mental and physical health, commuted by car less, and were more likely to like their neighbourhood. These differences persisted for up to three years post-move, except for physical health. Area deprivation, urbanicity, household income, and life-course stage emerged as influential moderators with, for example, recent movers into affluent areas experiencing lower physical health than settled residents, and movers into rural areas expressing less neighbourhood satisfaction. Residential relocation introduced movers with distinct characteristics into areas, potentially affecting the context in which potential public health interventions aiming to influence active travel would operate. Third, I examined how recent movers and longer-settled residents responded to a new Guided Busway and its associated walking and cycling path in the Cambridge region. Using longitudinal data from the Commuting and Health in Cambridge study, I found that living closer to the Busway was significantly associated with increased active commuting among settled residents, but not movers. However, the estimated effect sizes were similar across groups, and no significant interaction was detected, suggesting broadly comparable behavioural responses—contrary to expectations. This lack of differential effect was not explained by differences in exposure, awareness, or perception of the intervention. Instead, it may reflect a combination of contextual and methodological factors, including short-distance moves, high baseline activity levels among movers, overlapping life changes, and limited statistical power. In a setting like Cambridge, where active commuting is already culturally embedded, newcomers may arrive with similarly positive orientations toward active travel, limiting variation in responsiveness. These findings highlight the need for population-wide evaluations of environmental interventions and caution against the common practice of excluding movers. While their responses may not always differ starkly, overlooking movers risks missing context-dependent patterns—especially given their higher mobility, distinct sociodemographic profiles, and greater risk of poor health. Lastly, I developed the first longitudinal, relocation-focused area classification for Great Britain using a novel application of Group-based Multi-Trajectory Modelling (GBMTM) to small-area census data from 1981 to 2011. The resulting classification identified six distinct clusters based on indicators of in-migration, age, international origin, and tenure—revealing long-term trends such as studentification, continued inner-city in-migration, and a tenure-based North–South divide likely reflecting income disparities. Interestingly, the pattern of relocation clusters was consistent across urban areas, regardless of size or location, suggesting similarities in how relocation is experienced across Great Britain. Compared to existing general-purpose or cross-sectional migration classifications, my new classification offered additional insights. By summarising complex relocation patterns, the classification offers a new way to consider how such changes may influence responses to interventions—such as those promoting active travel—and lays a foundation for future research that seeks to account for local context in public health and transport planning. The findings from my thesis provide new insights into how relocation, and associated changes in the environment, household, or lifestyle, affect travel behaviour. Movers exhibit distinct characteristics, particularly in their health, travel behaviour, and, to some extent, their responses to environmental interventions, that can persist for years post-move. These findings highlight the importance of understanding variations in travel behaviour and interventions responses across population groups, and underscore that not everyone needs and benefits from active travel interventions in the same way. Such differences can contribute to, or exacerbate, existing health inequalities, particularly as my research shows many movers to have worse health than settled residents. My area classification further demonstrates that the risk of such misalignments varies across space. Inner cities—common targets for active travel interventions—experience high population turnover, which can shift local characteristics and perceptions, potentially altering how people respond. This may widen the gap between expected and actual intervention impacts. Relocation, therefore, emerges not only as an individual experience but as a population characteristic that shapes the social and demographic context in which interventions are implemented. Crucially, if movers are excluded from evaluations of public health interventions, such differences are overlooked. Future research should focus on including movers and other population subgroups in evaluations and improving methods to assess intervention impacts in individuals undergoing concurrent life changes like relocation. Recognising relocation as a contextual factor may further help tailor interventions to local population dynamics and enhance their relevance and equity. In practice, interventions that are flexible and adaptable to changes over time, could improve their effectiveness and equity across the whole population.