Wheeled mobile driving simulators (WMDS) intend to cue the motion of road vehicles by moving a tire-bound, electrically driven, omnidirectional platform. The motion space of a WMDS is a planar surface, which can theoretically be increased infinitely without having to modify the system itself. The concept therefore has high potential to represent scenarios with long-lasting, longitudinal and lateral accelerations with high immersion. For this reason, the Technical University of Darmstadt and the Technische Universität Dresden are both independently developing full-scale prototypes of a WMDS. Both are currently working on common research questions and challenges, which arise from the tire characteristics and the unboundness of the system. This paper aims to give an overview of the two simulator designs and an insight into the main research topics and solution approaches for the development of wheeled mobile driving simulators.