It is intended to use professional testers in the association area of Zweckverband Nahverkehr Rheinland, with the aim of guaranteeing a continuous quality analysis of the SPNV operation. Thus, a functioning Profitestersystem allows a more independent and faster detection of quality problems on the SPNV lines. At the same time, the profit testers should not only be used to check the quality of operations, but also to evaluate the station's SPNV quality and the quality of the distribution infrastructure.

See point "II. Service description "of the contract documents.