As the complexity and interdependence of different infrastructure systems increases, so do risks that cannot be dealt with using “classic” risk management methods. Thus, one investigates the “vulnerability” of entire infrastructure systems, such as transport and communication systems of a region to the failure or removal of their individual elements. On this basis, the priorities for risk optimization can be determined. In such cases one speaks of the criticality of the infrastructure. Procedures are being developed that will make it possible to plan measures to optimize the criticality of the infrastructure on the basis of identified indicators.
The criticality of the infrastructure is defined as follows:
“relative measure of the importance of an infrastructure in terms of the consequences that a disruption or breakdown has for the security of supply of essential goods and services to society”. 
- https://www.kritis.bund.de/SubSites/Kritis/DE/Servicefunktionen/Glossar/Functions/glossar.html?lv3=2254842&lv2=4968594 (aufgerufen am 22.07.2019)