A lot of work shows that contemporary urban developments are part of a process of recomposition of cities brought about by facilitated mobility and the trivialisation of car driving. In the context of this article, we deal with this issue by examining, for the Belgian context, how the relaxation of obstacles to mobility interferes with the residential logic of families in training. A review of the contemporary situation was first carried out. We present the main links between residential choices, age groups and life paths. We also analyse the relationship between, on the one hand, the observation of peri-urban sprawl and, on the other hand, the land pressure faced by households in training. Secondly, the contemporary situation is confronted with developments over the last five decades. These analyses carried out for the Liège urban region make it possible to combine the three tables explaining the timing of the life cycle, the effect of generational renewal and the impact of the socio-economic context. From this work, we note that facilitated mobility leads to a divisive population enrolment. Like social groups, demographic groups are becoming more and more geographically segregated in an urban region largely reconstituted by car mobility.