Due to the increasing amount of freight traffic on German motorways there is an increasing demand for parking facilities for trucks at motorways. In addition to the long-term expansion of the capacity of parking facilities, potentials for improving the situation for truck parking are seen in using telematic parking guidance systems. A requirement for such a parking guidance system is an effective and reliable detection of the occupancy of the parking facilities. So far, there is no testing procedure for systems for the area-wide detection of parking occupancy uniformly and in a comparable manner. For this purpose, functional criteria for a detection system with areawide detection have been compiled in the working group “Lkw-PLS” consisting of representatives of national and federal road authorities. As part of the Research and Development project “Scientific monitoring of the digital test field on the A 9 between Munich and Nuremberg”, a uniform procedure for functional and suitability testing of these criteria was developed at the Federal Test Field PWC Gelbelsee-West. This testing procedure shall be used as a basis for future tenders for parking detection systems on parking facilities at motorways. The procedure has been subjected to a practical test and has been released for use in official testing.