Hybridization of survey methods for understanding senior citizens’ mobility in the European Metropolis of Lille (MEL)

Following a 2016 face-to-face mobility survey in the European Metropolis of Lille (MEL), a significant increase in journeys by senior citizens was observed. Given the rising proportion of people aged 65 and over, due to increased life expectancy and the aging of the baby-boom generation, MEL sought to better understand the mobility behaviors of this demographic. To address this, Cerema developed a multi-year data collection plan. Initially, the plan involved a quantitative panel survey and a complementary qualitative study. However, budget constraints led to the design of a new hybrid or mixed mode protocol combining both approaches. This revised method included in-depth qualitative interviews with senior volunteers to explore mobility practices and life transitions, followed by a quantitative telephone survey based on insights drawn from the qualitative phase. This annual process, running from 2019 to 2023, adapted its themes to reflect current events (e.g., the COVID-19 crisis, rising fuel prices, sustainability concerns). In parallel, a panel survey using self-administered questionnaires was conducted over four years. The objective of the paper is to present this innovative mixed-mode methodology, rare in France, for studying elderly mobility. It explains how the two survey types were integrated and how each contributed to a deeper understanding of changing mobility behaviors among seniors. Key indicators are used to illustrate relevance of a mixed longitudinal approach, to effectively capture the complex, evolving nature of senior mobility in the context of retirement, health decline, and new social roles.