Side impact protection through the use of padding is still somewhat controversial. Although it has been shown in a series of 17 cadaveric tests that paper honeycomb can reduce thoracic injuries dramatically, there are still concerns regarding the ability to provide protection for the thorax when there is no engagement of the shoulder with the intruding side structure of the car. There is also concern as to what effect the padding would have on the occupant if the width of the vehicle remained unchanged and the free air space between the padded surface and the occupant is decreased. This paper describes the development of a one-dimensional lumped parameter model to simulate the cadaveric experiments carried out at Wayne State University and its validation. The model is then used to study the protective effect of the shoulder on the thorax and the effect of the padding on the force and duration of impact sustained by the occupant when a thick padding is used. It was found that the shoulder can provide substantial protection to the thorax and without shoulder engagement, the force on the thorax can be approximately 45% higher. This calls for additional cadaveric testing since the existing side impact dummies are apparently too stiff to be representative of the human. As for the loss of free air space due to the padding, the model predicted an increase in the force level and in thoracic deformation if the padding is too stiff.