Computational Investigation of Factors Influencing Vehicle Passengers' Safety Performance in Automated Driving Systems (ADS)

Abstract

As Automated Driving Systems (ADS) and shared mobility technologies become integral to transportation, mitigating injury risks for vehicle occupants has become increasingly critical. This dissertation presents computational investigations into key factors influencing passenger safety, with a focus on pre-crash maneuvers, and rear seat safety in mid-sized male occupants. \ \Initially, the influence of pre-crash maneuvers, such as braking and combined braking-turning events, was evaluated using finite element simulations with human body models. Results indicated that these maneuvers significantly altered occupant posture, leading to earlier and safer interactions with airbags and reducing head and neck injury risks. Factors such as seat position and recline angle showed major impacts on head injury criteria (HIC), brain injury criteria (BrIC), and neck injury criteria (Nij), highlighting the critical role of occupant positioning before a crash. Next, full-body injury risks for occupants in the rear seats were analyzed using detailed finite element models. Simulations with various modern seat configurations and advanced restraint systems revealed high injury risks, particularly due to submarining, where occupants slip under the seatbelt. Seat design features such as seat pan angle and restraint type influenced these risks. While advanced restraint systems reduced injuries, they did not fully prevent them, demonstrating a clear need for improved rear-seat safety. Lastly, the combined effects of pre-crash occupant motions and rear seat designs on occupant safety were explored using a simplified seat model in a rear seat environment. This investigation showed that pre-crash braking led to an out-of-position posture in rear-seated occupants, resulting in a near certainty of serious head injury due to the absence of rear airbags. Overall, this research emphasizes the necessity of integrating pre-crash occupant positions and improved rear seat design into safety assessments, particularly as ADS and shared mobility become prevalent. Future studies should further explore diverse occupant types, varied crash conditions, and active safety interventions to continue advancing passenger safety.