Side Impact Protection - Occupants in the Far-Side Seat

Abstract

Much of the applied vehicle side impact occupant protection research to date has concentrated on occupants seated beside the struck side of vehicles. These occupants are defined as ‘near-side occupants’. Regulatory side impact test standards focus exclusively on this scenario. Real world crash evidence however has shown that occupants seated on the side away from the struck side, defined as ‘far-side occupants’, are still subject to a risk of injury. Relatively little research literature is available that addresses the protection of far-side occupants. Existing three-pint seat belt restraint systems were primarily designed for frontal impacts. Consequently, there is an inability for these systems to perform as effectively under lateral loading, compared to longitudinal loading. This is particularly the case for far-side occupant restraints, where the occupant's upper tom has often been observed to slip out from under the sash part of the seat belt system. This paper examines side impact epidemiology from an injury causation perspective, and endeavours to explain evidence indicating head injuries and seat belt related injuries constitute a significant proportion of all far-side impact injuries. Injury mechanisms and key dynamic parameters governing injury severity are detailed. Computer models simulating the dynamic motion of vehicle far-side occupants are described. Occupant kinematics and injury parameters from the models are then compared with real world crash case studies. The paper finally suggests vehicle design strategies which are likely to reduce far-side injuries. Some alternative restraint systems are proposed as potential countermeasures to reduce occupant injuries.