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This paper presents a review of web-sensitive locking retractors that are designed to prevent webbing payout of occupant restraint systems in emergency conditions. Investigation of the design and function of such devices reveals variables that affect their operation, which, when properly considered, allows the designer or user to assess their suitability in various applications. A description of web-sensing locking retractors and an explanation of their theory of operation shows how design, manufacturing, and application variability can affect their desired performance. Changes to design, manufacturing methods and testing procedures, and reconfiguration of applications are considered to improve their reliability.

This exploratory study investigated the effect of cognitive workload on manual lap belt usage in automatic restraint systems consisting of a passive motorized shoulder belt and a separate manual lap belt. Previous observational studies showed that, while these types of passive automatic restraint systems increased shoulder belt usage, occupants frequently did not engage the manual lap belt. This omission put the occupants at a significantly increased risk of injury in a crash. These studies also suggest that forgetfulness was one of the main reasons that occupants did not engage the manual lap belt. The objective of this study was to quantify manual lap belt usage with this type of automatic restraint system under varying cognitive workloads. Ten subjects participated in two testing sessions consisting of a low and high cognitive workload. During each test session, the subjects drove around a pre-defined course where they exited the vehicle at five locations to perform specific tasks.

This paper reviews seven motor vehicle crashes from the authors' files, in which a child occupant was using a booster-with-shield type child restraint and sustained serious injury.

This paper discusses the ongoing real-world effects on the wearers of restraint systems which are subject to a retractor's failure to lock in a timely manner. Investigation of the ELR performance using both detailed physical examination and inductive methods enables accurate assessment of successful ELR locking at the first opportunity in the crash sequence. Available methods to determine the reliability of the ELR's crash performance are considered and analyzed for assessment of reliability to enable adequate seat belt wearer protection. Corrective measures are analyzed to probe the feasibility of federal safety regulation amendments to mandate a reliability analysis on the propensity for the ELR's failure to lock in a timely manner.

Actual automobile crash scenarios include “wheels-first” landings after the vehicle leaves the road surface and becomes momentarily airborne. These events generate a vertical acceleration vector in a headward direction (+Gz) along the occupant's spinal axis. In this scenario, the vehicle occupant could be in contact with the seat bottom or seat back cushions, or displaced several inches off both the bottom and/or back cushions depending on the effectiveness of the restraint configuration and the dynamics of the vehicle's motion. Military ejection seat researchers have shown that occupant response to +Gz acceleration loading is amplified as a function of the spring-mass damping characteristics of the total system (i.e., the occupant and seat/restraint/cushion subsystems). This amplification phenomenon, commonly known as “dynamic overshoot”, has the propensity to vary widely depending on the built-in controls within a given seat bottom design.