A side impact is one of the severest crash configurations among real-world accidents. In the US market, even though most vehicles have achieved top ratings in crash performance assessment programs in recent years, there has hardly been any sign of a decline in side-impact fatalities for the last few years, according to statistics retrieved from the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System. In response to this trend, the Insurance Institute for Highway Safety (IIHS) is planning to introduce a new test protocol for side impact assessment. One of the points to be clarified in current side impact tests is whether the present side moving deformable barrier (MDB), which includes the barrier face and cart, faithfully reproduces a real-world car-to-car crash. Hence, this study identifies key factors for reproducing car-to-car side impacts based on a series of parametric computer aided engineering (CAE) investigations of the barrier face dimensions and stiffness. Reproducibility of MDB tests was studied in terms of three indices of struck vehicle behavior (1) kinematics, (2) body deformation patterns (plan and front view) and (3) dummy injuries. The results revealed that three factors concerning the barrier face, namely, (a) height of the center of force (COF), (b) total barrier force and (c) lateral force distribution, are dominant for reproducing car-to-car side impact behavior.