PURPOSES : The purpose of this study is to investigate the correlation between occupant impact velocities and occupant injury indices under the restraint of an airbag and a seat belt, during frontal crash events. METHODS : The frontal crash test data of 93 tests conducted according to the Korea New Car Assessment Program (KNCAP) were investigated. The test data was measured by using a dummy to obtain occupant injury indices for the head, chest, neck, and upper legs. Occupant impact velocities (OIVx and OIVz) were calculated from the head acceleration of the test dummy. Pearson's correlation analysis and regression analysis were used to investigate the correlation between occupant impact velocities and occupant injury indices. In addition, the occupant impact velocities at the center of gravity of a vehicle, obtained by using the accelerations measured at the test vehicle's B-pillars, were investigated. RESULTS: The OIVx threshold obtained from the test dummies, which corresponds to the HIC15 of 700, was 70 km/h for a sedan, and 72 km/h for an SUV, which is significantly higher than the occupant impact velocity of 44 km/h, the limit of the domestic guideline on “Installation and management guide for roadside safety facilities”. This difference can be attributed to the influence of the air bags and seat belts. Additionally, the OIVx threshold obtained from the center of gravity of the vehicle corresponding to the HIC15 of 700 was approximately 72 km/h. CONCLUSIONS: Occupant safety performance criteria for the condition that airbags operate and seat belts are restrained, are required for the frontal impact tests of road safety facilities using a collision velocity of 60 km/h or higher.