The Potential of the Mobility Transition for Tackling the Housing Crisis

Kurzfassung

Cities around the world face major challenges related to mobility and housing. Mobility systems require a transition towards sustainable mobility, in order to contribute to carbon neutrality, and more land is needed for the construction of flats, in order to tackle the housing crisis. The mobility transition (MT) entails a modal shift from motorised individual transport (‘MIT’; such as cars) towards active mobility (such as walking or cycling) in combination with public transport. This transformation could also free up urban land, as sustainable modes of transport are more land efficient than MIT (Randelhoff 2019). While research to date has focused on the on-street land consumption of MIT, off-street-automobile-infrastructure (‘OSAI’; such as petrol stations, car dealerships or car parks) has not yet been considered systematically. There has been no research on the impact of the MT on the future land consumption of OSAI and the potential for land to be redistributed to other uses such as housing. The research question of this dissertation is: What is the potential of the mobility transition for tackling the housing crisis? To answer the question, I used the German capital of Berlin as a case study, which by law has committed both to reaching carbon neutrality by 2045 (EWG Berlin 2021), and to implementing the MT via modal shift in the transport sector (Berlin Mobility Act 2018). With a geo information system (GIS) I assessed the status quo of land consumption of OSAI and conducted a ‘spatial potential analysis’, in order to assess the possibility of redistributing OSAI for housing. I developed a backcasting approach, based on Berlin achieving its targets on carbon neutrality and successfully implementing the MT. I used the auxiliary indicators ‘modal share’ and ‘motorisation rate’ to calculate the amount of land, which could become available as less land would be required for OSAI. Based on this, I calculated the number of flats that could be built if the MT was implemented. My analysis demonstrates that OSAI covers 22.2 km² of Berlin, which equates to 4.5% of Berlin’s settlement area. This is significant, considering it is more than the total area of the district of Friedrichshain-Kreuzberg (20.4 km²), which is home to 290,000 people (approximately 7.7% of Berlin’s population). I found that the proportion of OSAI is particularly high in inner-city districts, for example, 8.2% in Friedrichshain-Kreuzberg (where only 14% of the trips are done by MIT). My analysis shows that OSAI typically has a low-density level, and is mainly located in areas that are statistically subsumed under the land use categories ‘housing’ and ‘commercial/ industrial/retail’ (Umweltatlas Berlin, Stadtstruktur – Flächentypen 2021). Only 5.5% of OSAI is statistically subsumed under the category ‘traffic’. I found that 65% of OSAI land parcels could be rededicated for housing. About one-third could not be rededicated, as this is either difficult due to the type of architecture (e.g. underground car parking), because the OSAI belongs to the green and open space land use categories or could not be allocated to any land use type. With my backcasting approach I calculated that if the mobility transition takes place up to 107,371 flats could be built on the land that would no longer be needed for OSAI, housing more than 193,000 people. My desktop research confirms that examples of redistribution of OSAI land towards other uses, such as housing, already exist in Berlin. In order to leverage this potential, there needs to be, above all, more transparency around the amount of land currently used for OSAI. I propose an open-access cadastre for OSAI as one of five policy recommendations. This dissertation is the first study to analyse the connection between the MT and housing potentials. It demonstrates the significant potential of the MT to help address the housing crisis. The findings of my dissertation provide a new argument for implementing the MT and could initiate a public discourse on the larger pattern of urban development.