An autonomous emergency braking (AEB) system can detect emergency conditions using sensors (e.g., radar and camera) to automatically activate the braking actuator without driver input. However, during the hard braking phase, crash conditions for the restraint system can easily change (e.g., vehicle velocity and occupant position), causing an out-of-position (OOP) phenomenon, especially for unbelted occupants entering the airbag deployment range, which may lead to more severe injuries than in a normal position. A critical step in reducing the injury of unbelted occupants would be to design an AEB system while considering the effect of deployed airbags on the occupants. Thus far, few studies have paid attention to the compatibility between AEB and airbag systems for unbelted occupants.This study aims to provide a method that combines AEB and airbag systems to explore the potential injury reduction capabilities for unbelted occupants. By dividing the distance between the driver’s head and the top of the steering wheel into five regions, the possible area of head position was obtained by computational investigation for several combinations of braking acceleration and time. Using braking acceleration and time as input features, as well as real-time head position in one of five regions as an output feature, a support vector machine (SVM) classification model was trained and validated by the obtained data set. The ride-down efficiencies of the different regions were compared, and optimization for maximum delta-V reduction was conducted based on the SVM model under the prerequisite of guaranteeing high ride-down efficiency and appropriate forward displacement for the occupant. By utilizing the above-mentioned method to design the integrated safety systems including AEB and airbag systems, the safety benefits of this approach were demonstrated by comparing with those of the original design.