Urban centers are characterized by a central attractor, usually the historical city which have concentrated economical activity from years ago, surrounded by suburbs of different types (economical, industrial, or residential). Various kind of residential suburbs exists, and there is a high degree of residential segregation by social level linked with a high degree of socio-economic heterogeneity (Fine et al. 1971 [1]). Furthermore, low-income housing tends to be concentrated in particular undesirable housing segments (Van Kempen et al. 1989 [2]). More and more people will live in cities in the next few decades. How cities will face this demographical challenge ? The United Nation defined in their sustainable development objectives to allow every human to be in good wealth and promote well-being (UNO 2015 [3]). But how can we consider the well being ? We will try through our study to define a way to measure a part of this well-being and good wealth by computing a population vulnerability index. We will use the municipality of Vernier in the Geneva canton in Switzerland to define in the best way this index.