Air and knee bolster restraint system: laboratory sled tests with human cadavers and the Hybrid III dummy.

UNLABELLED Growing evidence from data base and laboratory studies demonstrates effective occupant protection with the airbag supplemental restraint and seatbelt restraint system. Concern that drivers of vehicles equipped with airbags may assume adequate protection without concomitant seatbelt use prompted the study of unbelted occupant behavior in frontal crashes. OBJECTIVE To evaluate the crash protection afforded unbelted drivers in airbag-equipped vehicles. DESIGN Six laboratory sled tests were conducted with a production driver's side airbag and knee bolster restraint system but without a seatbelt restraint system. MATERIALS AND METHODS Four human cadavers and the Hybrid III dummy were used as occupants in 32 km/h and 48 km/h tests with a simulated mid-size vehicle. MEASUREMENTS AND MAIN RESULTS Head contact with the windshield/header region of the simulated vehicle and abdominal impingement on the lower rim of the steering wheel were noted in all tests. Autopsy examinations and radiographic images identified extensive spinal and thoracic trauma in addition to lower extremity and facial injuries. Injury Severity Scores were considered severe to critical for all occupants. CONCLUSIONS The evidence suggests the need to emphasize the use of seatbelts in conjunction with airbags and to develop a redesigned airbag and knee bolster system to control occupant kinematics and loading more effectively.