In this chapter, we consider the problem of efficiently evacuating all people in an urban area from danger zones to safe zones. This problem, which has attracted major scientific interest and has been well-studied in literature, is indeed large-scale, and as such difficult to solve. In this work, we propose a solution method based on an islanding scheme. This decomposition approach takes into consideration the betweenness of a set of nodes in the transportation network, and aims to obtain clusters from those nodes that can be easily solved: the idea is to divide the flow more evenly towards multiple paths to safety, leading to a more robust evacuation process. We portray our results on several synthetic and reallife transportation networks. More importantly, we use a very large-scale network representation of the city of Jacksonville, Florida, in the USA to show that our approaches solve the problem, a feat that proved impossible for commercial solvers. We conclude this study with our observations and plans for future work.