Beyond a Single Snapshot: A Temporal Analysis of User Exposure in Mobility Data

• Lucas G. S. Félix UFMG / Inria
• Vinícius da F. Vieira UFSJ
• Anne Josiane Kouam Inria
• Alexandre G. Evsukoff UFRJ
• Nadjib Achir Inria
• Aline C. Viana Inria
• Jussara M. Almeida UFMG

DOI: https://doi.org/10.5753/sbrc.2026.19743

Abstract

The increasing availability of large-scale urban mobility data intensifies privacy risks, as users can often be re-identified from a small number of spatio-temporal observations. Although mobility profiles have been widely used to characterize users’ movement behavior, their role in explaining and guiding privacy protection strategies remains unclear, particularly from a longitudinal perspective. In this paper, we investigate the temporal relationship between mobility profiles and user vulnerability in urban mobility data. Our methodology combines mobility profile identification with two complementary vulnerability quantification techniques: uniqueness, capturing spatio-temporal vulnerability, and a hypercube-based approach, capturing behavioral vulnerability. Using mobile phone data from the city of Rio de Janeiro over three consecutive weeks, we conduct a longitudinal analysis of how mobility profiles and vulnerability levels evolve over time. Our results show that, while users frequently change mobility profiles across weeks, their vulnerability levels remain largely stable. Moreover, we find that mobility profiles do not significantly differentiate users’ vulnerability, suggesting that profile-based protection strategies may be ineffective. Finally, we show that behavioral vulnerability is consistently concentrated in a small subset of mobility metrics, indicating that protecting these dimensions alone may substantially reduce users’ exposure. These findings provide practical insights for the design of targeted and efficient privacy-preserving mechanisms for urban mobility data.

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