This paper investigate the causal relationships that exist between the motility, defined as the personal ability to be mobile (Kaufmann et al., 2015), and mobility behaviors. To do so, we use the first wave (2018) of the "national daily mobility panel" survey (PaNaMO), which is a longitudinal Internet study for the social sciences (ELIPSS). From a methodological point of view, we use latent variables to construct an aggregated motility index based on each of its pillars (accesses, skills and aspirations). This allows us to get a structural vision of the concept. Building a motility typology, we show by a comparative approach how this concept may lead to rediscover inequalities related to mobility. Conceptually, our motility index reveals how a significant part of the population can be mobile without high competencies to do so. Operationally, it shows the importance of the car mode for people with low mobility aptitudes, that is motility.