The Death and Life of Great Italian Cities: A Mobile Phone Data Perspective (1603.04012v1)

Abstract: The Death and Life of Great American Cities was written in 1961 and is now one of the most influential book in city planning. In it, Jane Jacobs proposed four conditions that promote life in a city. However, these conditions have not been empirically tested until recently. This is mainly because it is hard to collect data about "city life". The city of Seoul recently collected pedestrian activity through surveys at an unprecedented scale, with an effort spanning more than a decade, allowing researchers to conduct the first study successfully testing Jacobs's conditions. In this paper, we identify a valuable alternative to the lengthy and costly collection of activity survey data: mobile phone data. We extract human activity from such data, collect land use and socio-demographic information from the Italian Census and Open Street Map, and test the four conditions in six Italian cities. Although these cities are very different from the places for which Jacobs's conditions were spelled out (i.e., great American cities) and from the places in which they were recently tested (i.e., the Asian city of Seoul), we find those conditions to be indeed associated with urban life in Italy as well. Our methodology promises to have a great impact on urban studies, not least because, if replicated, it will make it possible to test Jacobs's theories at scale.

• The paper uses mobile phone data and web sources to empirically test Jane Jacobs's urban vitality conditions in six Italian cities.
• The study finds that Jane Jacobs's conditions, particularly third places and small block sizes, significantly correlate with urban vitality in Italian cities.
• This research provides a practical framework for city planners to monitor and enhance urban environments dynamically using digital data sources, extending Jacobs's theories globally.

Understanding the Vitality of Italian Cities through Mobile Phone Data

This paper presents a comprehensive paper investigating the applicability of Jane Jacobs's theories on urban life in Italian cities, using mobile phone data as a novel approach to examining urban vitality. Jane Jacobs, in her seminal work "The Death and Life of Great American Cities," posited four conditions essential for urban vitality: diverse land use, small blocks, aged buildings, and dense concentration of people and structures. The paper seeks to empirically test these conditions within the context of six large Italian cities—Bologna, Florence, Milan, Palermo, Rome, and Turin—leveraging data from mobile phones and various web-based sources.

Methodology

The research employs mobile phone activity data, specifically Internet usage records, to estimate urban vitality, with the rationale that mobile phone usage correlates with human activity patterns. This data provides a passive and ubiquitous measure of urban life, overcoming limitations of traditional survey methods. Additionally, a diverse array of data sources, such as the Italian Census, OpenStreetMap, and Foursquare, are used to construct measures reflective of Jacobs's conditions within these cities.

The paper details numerous metrics for each of Jacobs's specified conditions:

• Land Use: Metrics such as land use mix, closeness to small parks, and third places are adopted to measure diversity.
• Small Blocks: Metrics include average block area and intersection density.
• Aged Buildings: Metrics computed include average building age and diversity of building age.
• Concentration: Metrics such as population density and employment density are considered.
• Border Vacuums: Distance to large parks, railways, highways, and water bodies assesses potential obstacles to urban activity.

An Ordinary Least Squares (OLS) regression model is used to analyze the relationship between the constructed metrics and district activity density, providing statistical validation of Jacobs's conditions in this unique geographical context.

Results and Implications

The paper demonstrates that Jacobs's conditions are indeed associated with urban vitality in Italian cities. Notably, the presence of third places and small block size significantly correlates with higher mobile phone activity, thus indicating vibrant urban life. Third places such as cafes and pubs are pivotal to fostering social interactions and community building beyond the home and work environments. Furthermore, small blocks facilitate pedestrian movement and the spontaneous urban interactions Jacobs advocated.

The findings suggest that Jacobs's model holds validity beyond the American context, with generalizable implications for European urban planning. The use of mobile phone data introduces an innovative methodology for urban studies, allowing for scalable, real-time monitoring of urban dynamics without the high costs and limitations of traditional surveys.

Theoretical and Practical Implications

The paper reaffirms the theoretical foundations laid by Jacobs regarding urban planning and sociological city dynamics, showing that the principles of urban diversity and vitality are valuable across different cultural contexts. Practically, the research methodology provides a framework for city planners and policymakers to utilize existing digital data sources to monitor and enhance urban environments dynamically. Such an approach is promising for real-time city dashboards and evaluations of zoning law impacts, providing actionable insights into urban development and social cohesion strategies.

Conclusion

This research marks an important step towards integrating digital data into urban studies, validating long-held theories with empirical data across diverse urban landscapes. The findings reinforce the importance of creating multi-functional, pedestrian-friendly urban spaces and highlight the lasting influence of Jacobs's work in guiding contemporary urbanism. Future research can extend these methods to additional global contexts or explore further the temporal dynamics of urban activities through mobile data, promising richer insights into the fabric of city life.