Yay! Elias Willberg will defend his PhD thesis “Measuring sustainable accessibility: Geospatial approaches toward integrating people and the environment”
Opponent professor Trisalyn Nelson, Jack and Laura Dangermond Endowed Chair of Geography, University of California, Santa Barbara, custos Tuuli Toivonen
Time: Friday 2nd June, 12 o’clock noon
Place: Suomen Laki- sali, Porthania, Yliopistonkatu 3
Abstract of the thesis
The central challenge of our societies is how to satisfy people’s basic needs and guarantee a good life for everyone, while staying within the safe planetary limits. Spatial accessibility, meaning the potential of opportunities to interact with other people, activities, and places, is essential for social and environmental sustainability. During recent decades, measures of accessibility have become an everyday tool for urban and transport researchers. By examining the satisfaction of basic needs, accessibility strongly links to social well-being and equity. Accessibility-oriented planning can at best enable environmentally sustainable solutions, which do not increase travel demand but support shorter distances and thus the increase of walking and cycling. In reality, improving accessibility is often based on improving the conditions of motorised transport, and the results can be environmentally harmful. Such contradictions remain sparsely studied in accessibility research due to the lack of holistic approaches. Most often, social and environmental concerns are addressed separately, even if the integration of perspectives would be central to promoting sustainability.
In my thesis, I take up this integration challenge. I develop conceptual and methodological approaches to bridge social equity and environmental sustainability in accessibility research. Conceptually, I present a model for measuring accessibility that integrates social equity, environmental boundaries, and their tensions and trade-offs. Methodologically, I leverage the opportunities of new geospatial data and tools. I develop geographical measures of accessibility, which are sensitive to the variation between people and temporal conditions, as well as to the travel environment. Empirically, I approach the integration of social and environmental goals from the perspective of contemporary themes in sustainable accessibility. The themes include the idea of 15-minute cities, environmental exposures during travel, and bike-sharing systems as accessibility promoters. I use the Helsinki Metropolitan Area to test the new approaches empirically. Hence, my thesis also offers place-specific understanding on accessibility and mobility patterns in this area. I focus my thesis on walking and cycling due to their vital role for sustainable transport. The thesis consists of five scientific articles, the first of which is conceptual, the second an overview of data sources, and the last three empirical and methodological, located in Helsinki or in the wider metropolitan area.
The results of my thesis show the need, but also present means, to combine social equity and environmental sustainability when measuring accessibility. There is a need to diversify the ways in which the travel costs are measured. Accessibility should increasingly be measured not only through travel time, but considering its full costs, such as environmental impacts. Furthermore, measures based on travel time should be developed to be more sensitive to the temporal and interpersonal variation. My results show that this can yield more realistic presentations of accessibility, especially concerning the opportunities of less mobile groups to travel sustainably. Promisingly, new geospatial data and tools offer increasingly means for the necessary development work, supporting researchers and planners. However, there is a need for careful consideration in the selection of data sources, as limitations and biases abound. Finally, my thesis highlights that multidisciplinary and transdisciplinary approaches are essential in accessibility research to support evidence-based decision-making that promotes real progress towards sustainability.
The thesis synopsis is available in HELDA: https://helda.helsinki.fi/handle/10138/357760
The thesis contains the following scientific articles:
- Willberg, E., Tenkanen, H., Miller, H. J., Pereira, R. H. M., & Toivonen, T. (2023). Measuring just accessibility within planetary boundaries. Published as a preprint: https://osf.io/3h6wn/
- Willberg, E., Tenkanen, H., Poom, A., Salonen, M., & Toivonen, T. (2021). Comparing spatial data sources for cycling studies – a review. In M. Mladenović, T. Toivonen, E. Willberg, & K. T. Geurs (Eds.), Transport in Human Scale Cities (pp. 169–187). Edward Elgar Publishing Limited. https://doi.org/10.4337/9781800370517
- Willberg, E., Salonen, M., & Toivonen, T. (2021). What do trip data reveal about bike-sharing system users? Journal of Transport Geography, 91, 102971. https://doi.org/10.1016/j.jtrangeo.2021.102971
- Willberg, E., Fink, C., Toivonen, T. (2023). The 15-minute city for all? – Measuring individual and temporal variations in walking accessibility. Journal of Transport Geography 106, 103521. https://doi.org/10.1016/j.jtrangeo.2022.103521
- Willberg, E., Poom, A., Helle, J., & Toivonen, T. (2023). Cyclists’ exposure to air pollution, noise, and greenery: A population-level spatial analysis approach. International Journal of Health Geographics 22, 5. https://doi.org/10.1186/s12942-023-00326-7