The aim of this work was to develop a realtime simulator for vehicle interior noise in varying load situations. Using this simulator, laboratory hearing tests which are common in the automotive industry may be executed more realistically than by using recorded sounds without any interaction possibility. A simplified model for the load situation of a car is presented. Using this model, the interpolation between the prerecorded signals is performed to obtain signals for other load situations. Furthermore, an analysis/resynthesis system for the interior noise of cars is introduced which only needs a sparse set of parameters.