<div class="section abstract"><div class="htmlview paragraph">Assessment of the physical evidence on a seat belt restraint system provides one source of data for determining an occupant’s seat belt use or non-use during a motor vehicle crash. The evidence typically associated with loading from a restrained occupant has been extensively researched and documented in the literature. However, evidence of loading to the restraint system can also be generated by other means, including the interaction of an unrestrained occupant with a stowed restraint system. The present study evaluates physical evidence on multiple stowed restraint systems generated via interaction with unrestrained occupants during a full-scale dolly rollover crash test of a large multiple passenger van. Unbelted anthropomorphic test devices (ATDs) were positioned in the driver and right front passenger seats and in all designated seating positions in the third, fourth, and fifth rows. Occupant kinematics during the dolly rollover were evaluated through on-board and off-board real-time and high-speed video, and physical evidence on the restraint systems was documented. Analysis of the occupant kinematics demonstrated multiple ATD interactions with stowed restraint systems in the vehicle, which generated corresponding physical evidence on those restraint systems. The findings of the present study demonstrate that the presence of physical evidence on the restraint system alone is insufficient for determination of occupant seat belt usage. A methodology for assessing restraint webbing and hardware evidence in the context of occupant seat belt use versus non-use is detailed. Thorough documentation of the restraint system physical evidence, evaluation of the occupant kinematics and injury patterns, and evaluation of the restraint system evidence as it relates to the body habitus of the occupant of interest can provide an objective scientific basis for the determination of occupant restraint status.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Airbag and seat belt pretensioner deployment characteristics depend on multiple factors, such as the magnitude, direction, and rate of vehicle deceleration as detected by vehicle crash sensors and evaluated by vehicle-specific algorithms. Frontal airbag and pretensioner deployments are likely to be commanded during frontal crash events with high initial vehicle deceleration typically associated with high vehicle change in velocity (delta-V). However, within a range of moderate changes in vehicle speeds, referred to as the “gray zone,” a vehicle-specific algorithm may or may not command deployment depending on crash pulse parameters and occupant sensing, among other items. Publicly available testing in the moderate-speed range is lacking and would be useful to evaluate the effects of airbag and pretensioner deployment on occupant kinematics and loading. In this study, sled tests were performed using a standard passenger vehicle buck simulating frontal deceleration impact events in a “gray-zone” severity of 19 kph (12 mph) delta-V and in a typical deployment severity of 32 kph (20 mph) delta-V. Matched sled tests were performed with and without airbag deployment with instrumented Hybrid III 50th percentile anthropomorphic test devices (ATDs) properly belted in the driver and front passenger seats. Additionally, one paired test was conducted at 19 kph with and without pretensioner deployment in the presence of airbag deployment. Airbag deployment for the 19 kph delta-V tests did not significantly affect occupant kinematics or loading compared to the non-deployment tests, while some differences were apparent for the 32 kph delta-V tests. In all tests, injury metrics were well below applicable injury assessment reference values (IARVs).</div></div>