On the one hand, in some cases an actualized, up-to-date, topologically appropriately connected Hungarian road graph can be reasonably costly. On the other hand, the actuality and the topologically appropriate connectivity of a freely available road graph cannot be ensured, and the improvement of its quality needs a lot of effort. Considering that the most important objective of the investigation is to estimate the changing of travel time and maximum flow values, it should also be considered that a road network graph – from a network vulnerability point of view – can contain several network elements that are of less importance, for example, a set of small edges representing the geometric properties of the graph (e.g., curves), motorway ramps, and so on. In accordance with this, sometimes, instead of applying an existing graph, generating a less complex network may seem to be a more competitive alternative. So in our investigation, the cities with the 40 largest numbers of inhabitants have been selected as the road network and settlement function nodes, the highways, the primary and secondary road elements of the network have been defined as components representing the links of the network. In accordance with this, the graph is built up from 131 nodes and 236 edges, as shown in Figure 62 (Török 2018).