Against discomfort of vehicles for wheelchair users, countermeasures such as a vibration absorber are required. To determine the optimal characteristics of the absorber, we had proposed the Comfort Evaluation Prediction System (CEPS) that can predict subjective evaluation from floor vibration, considering passengers' constitutions and wheelchair types. The purpose of this paper is to construct a model that simulates the vibration transmited to the passenger as part of the CEPS. We modeled a wheelchair-bound passenger and estimated unknown parameters by the result of a modal experiment. Then some simulations were carried out to suggest applicability of the model.