The Brazilian Automotive regulations that are aimed towards the safety of drivers, passengers and pedestrians have gone through recent changes to prevent and/or minimize injury and trauma from different types of accidents.Until now, National Traffic Council (CONTRAN) Resolution n° 14/98 required vehicles to only have safety belts for an occupant restraint system, and frontal airbags were not required. Since the recent CONTRAN n° 311/09 Resolution requires mandatory frontal airbags, the occupant restraint system must be tuned due to the interaction with different components that may make up the system, like safety belts with pretensioners and seatbelt load limiting devices.The present study was developed to optimize the restraint system of a current vehicle in production, while focusing on minimizing the vehicle complexity. The optimization tool helped to develop a robust restraint system for the frontal passenger during a frontal impact .The numerical computational model created was initially correlated with an experimental test, and then 72 simulations were performed to build the optimization matrix. The optimized parameters provided by the Design of Experiments (DOE) were simulated in the numerical computational model and also applied in an experimental test. The results presented excellent correlation and the goals of the optimization were achieved showing that this tool can help in future developments. This paper will review the methods used to study variables in restraint system with respect to their effect on occupant performance, as well as explain the final results from this optimization study.