TPF is subject to quality controls required by the Federal Office of Transport (OFT). One of their parameters for quality control is the Quality Management System (QMS). Mystery shoppers are regularly evaluating the services of TPF based on the criteria defined by the OFT, in particular the quality of the services, the passenger information, the cleanliness of the vehicles, the infrastructure and many other criteria. The system enables TPF to constantly improve the quality of its services.