In the process of dimensioning a tunnel lining support an optimized structural system is pursued to accommodate the inherent uncertainties associated with the geotechnical, hydro-geological, and environmental conditions. Particularly for geotechnics, uncertainty has become a major issue of scientific discussion according to a number of recent publications. At the same time, advanced performance criteria often require probabilistic assessments in order to quantify a structure’s safety and reliability or to inform life-cycle engineering decisions. This contribution demonstrates a novel design approach for the design assessment of concrete tunnel linings. The Index for the Capacity Utilization of Linings in Tunnels (CULT-I) introduced herein, facilitates the quantification of reliability of a tunnel lining support, while it aids toward a rationalized, performance-based design optimization with considerations on geotechnical uncertainty. Typical cases of shallow urban tunnels excavated in soft ground using different methods are presented demonstrating the practical application and feasibility of the proposed approach.