The human being, with his abilities and needs, is moved into the center of all design decisions, to ensure that new electronic assistance systems significantly reduce the still too high accident rates. Moreover, mobility in the elderly has to be guaranteed by assistance functions, for example in cars that compensate age-related weaknesses and wisely support available strengths. A central challenge of this application domain is the supply of design methodologies for the development of assistance systems that enable a continuous quality management in parallel to the design process from the viewpoint of the final end user. Therefore, on the basis of experiments in driving or flight simulators, OFFIS creates virtual test drivers and test pilots respectively as so-called cognitive models, and is embedding these into the industrial design process.