The Role of Time Inequality in Sustainable Mobility: Analyzing Socio-Spatial Disparities in German Cities

Sustainability policies are an important instrument in the effort to combat climate change, with considerable potential to transform urban spaces. Within the transport sector, one of the largest global contributors to CO₂ emissions alongside energy and industry, strategies such as the expansion of public transport, improving infrastructure for cycling and walking, and restricting private car use are essential to reduce emissions.

Research conducted in the United States (U.S) has demonstrated that access to sustainable mobility is not equally available to all social groups. Furthermore, the transition to sustainable mobility is often reinforces social inequalities. While active and public transportation modes reduce environmental burdens, they are often associated with higher financial and time costs compared to private car use. This discrepancy is frequently ascribed to urban structures, suburbanization, and the car-centric design of many cities. However, urban inequalities in Germany and Europe are distinct from those in the U.S., with lower residential segregation and better public transport. Nevertheless, private car use remains prevalent, contributing to continued transport emissions.

While research in the U.S. has primarily focused on economic and infrastructural barriers to sustainable mobility, time inequality has received little attention. Time inequality, defined as the unequal distribution of time across social groups, is a crucial aspect of social inequality. Especially capitalist societies, time is a valuable resource, and its scarcity can increase stress, reduce well-being, and limit quality of life by restricting the time available for personal needs and leisure activities.

This dissertation examines the relationship between time inequality and sustainable mobility in German cities through three empirical studies. It integrates extensive mobility data with detailed spatial, socio-economic, and demographic information from the “MiD” survey (Mobility in Germany, 2002 and 2017) and the "Mobicor" survey (Mobility in Times of the COVID Pandemic, 2020–2023).

The first chapter investigates how socio-spatial factors explain the environmentally friendly mobility behavior of individuals with higher educational attainment. The findings indicate that individuals with university degrees tend to reside more often in large cities and within those in central areas, resulting in shorter travel distances. Consequently, they utilize slower yet more sustainable modes of transport without incurring higher travel time costs.

The second chapter finds that immigrants in German cities require more time for their daily mobility for similar distances travelled. This disparity is partly due to residential patterns, as immigrants often live in disadvantaged neighborhoods with limited access to public transportation and local services. Additionally, qualitative interviews suggest that immigrants adjust their mobility behavior to avoid perceived unsafe situations in public spaces, which consequently increases their travel times.

The third chapter examines the impact of work from home (WFH) on daily mobility and care-work. The COVID pandemic demonstrated that WFH can reduce commuting times and associated emissions. However, previous studies suggest that WFH can also lead to an increased burden of care-work for women. This study investigates how WFH influences the time spent on care-work trips, finding that women with lower levels of educational attainment spend more time on care-work trips due to WFH compared to their male counterparts.

This dissertation contributes to research on inequalities in sustainability transitions by exploring how time inequality shapes sustainable mobility behavior. The findings indicate that merely expanding sustainable transport infrastructure is insufficient to ensure equitable sustainable transitions. Instead, structural and time barriers must be addressed to enable all social groups to participate in sustainable mobility.