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The Acoustic Startling Pre-stimulus (ASPS, i.e. a loud sound preceding a physical perturbation) was previously found to accelerate action execution in simple flexion exercises. Therefore in this study we examined if ASPS can accelerate take-over reaction times in restrained teen and adult drivers who were asked to reach for the steering wheel while experiencing sled lateral perturbations simulating a vehicle swerve. Results showed that adult drivers lift their hands toward the steering wheel faster with the ASPS versus without (161 ± 23 ms vs 216 ± 27 ms, p<0.003). However this effect was not found in teens or in trials where the drivers were engaged in a secondary task. Adults also showed reduced lateral trunk displacement out of the seat belt with the ASPS. The ASPS could represent a novel warning that reduces take over time and out-of-position movements in critical autonomous driving scenarios.

Previous research has suggested that the pediatric ATD spine, developed from scaling the adult ATD spine, may not adequately represent a child's spine and thus may lead to important differences in the ATD head trajectory relative to a human. To gain further insight into this issue, the objectives of this study were, through non-injurious frontal sled tests on human volunteers, to 1) quantify the kinematic responses of the restrained child's head and spine and 2) compare pediatric kinematic responses to those of the adult. Low-speed frontal sled tests were conducted using male human volunteers (20 subjects: 6-14 years old, 10 subjects: 18-40 years old), in which the safety envelope was defined from an amusement park bumper-car impact.

Accurate pediatric thoracic force and deflection data are critical to develop biofidelic pediatric anthropomorphic test devices (ATDs) used in designing motor vehicle safety systems for child occupants. Typically, postmortem human subject (PMHS) experiments are conducted to gather such data. However, there are few pediatric PMHS available for impact research; therefore, novel methods are required to determine pediatric biomechanical data from children. In this study, we have leveraged the application of chest compressions provided in the clinical environment during pediatric cardiopulmonary resuscitation (CPR) to collect this fundamental data. The maximum deflection of the chest during CPR is in the range of chest deflections in PMHS impact experiments and therefore CPR exercises the chest in ways that are meaningful for biofidelity assessment. Thus, the goal of this study was to measure the force-deflection characteristics of the thorax of children and young adults during CPR.

Comparative data of thoracic compression response between live vs. post mortem human subjects (PMHS) has been reported, but the live subject tests are often at low deflections and include the effects of muscle tensing. Novel technology has been developed that overcomes several of these limitations. Specifically, a load cell and accelerometer has been integrated into a clinical monitor-defibrillator to measure chest compression and applied force during live human cardio-pulmonary resuscitation (CPR). The sensor is interposed between the hands of the person administering CPR and the sternum of the patient. The objective of this study was to compare the thoracic force-deflection measured during adult CPR to that measured during hub-based loading of adult PMHS. CPR represents a unique setting in which to study the mechanics of the chest as the thorax is loaded to a maximum chest deflection similar to that seen in a frontal crash environment and the effects of muscle tensing are minimized.

The abdomen is the second most commonly injured region in children using adult seat belts, but engineers are limited in their efforts to design systems that mitigate these injuries since no current pediatric dummy has the capability to quantify injury risk from loading to the abdomen. This paper develops a porcine (sus scrofa domestica) model of the 6-year-old human's abdomen, and then defines the biomechanical response of this abdominal model. First, a detailed abdominal necropsy study was undertaken, which involved collecting a series of anthropometric measurements and organ masses on 25 swine, ranging in age from 14 to 429 days (4-101 kg mass). These were then compared to the corresponding human quantities to identify the best porcine representation of a 6-year-old human's abdomen. This was determined to be a pig of age 77 days, and whole-body mass of 21.4 kg.

Data presented in this paper demonstrated that the landscape for child occupant protection - the children and their restraints, vehicles, and crashes - is changing rapidly. Children are not small adults but are rather rapidly growing, developing, and changing and so too are their restraint needs. The past several years witnessed a growing awareness of these biomechanical challenges with the emergence of increased use of size-appropriate restraints for children under age 9 years and differences in patterns of injury by age. Vehicles involved in crashes with children reflect the trend overall: less passenger vans and cars and more light trucks, the majority of which are equipped with second generation air bags. The majority of crashes occurred on roads with posted speed limits below 45 miles per hour. The age group of particular concern is the newly driving teenage years (16-19) in which the crash and fatality rates are the highest among all age groups.

Although previous research has linked poor seat belt fit to abdominal organ injury for children, few have studied the pattern of pediatric abdominal injuries and its relationship to key characteristics beyond this primary association. In this study, data were obtained from a probability sample of 19,125 children, representing 243,540 children, under age 16 years who were enrolled in an on-going crash surveillance system which links insurance claims data to validated telephone survey and crash investigation data. The risk of AIS2+ abdominal injury was estimated for various crash, restraint, vehicle and child correlates and multivariate logistic regression was used to identify the relative importance of these predictors. Children 4–8 years of age were at the highest risk of abdominal injury: they were 24.5 times and 2.6 times more likely to sustain an AIS2+ abdominal injury than those 0–3 years and 9–15 years, respectively.

Restrained children between the ages of 3 to 15 years in crashes were identified in an on-going crash surveillance system (1998-2002) which links insurance claims data to telephone survey and crash investigation data. The risk of upper extremity injury associated with airbag deployment was estimated and a series of cases was examined using in-depth crash investigation to identify the mechanisms of these injuries. This study found that 3.5% of children who were exposed to a passenger airbag (PAB) received an upper extremity fracture, making them 2.5 times as likely to sustain an upper extremity fracture than children in similar crashes who were not exposed to a PAB. Female children were 2.2 times as likely to receive an isolated upper extremity fracture when exposed to a PAB than male children. The incidence rate, gender difference, and injury mechanism in children all appear to be similar to those of adults.

Little is known about the mechanism of pelvic injury in the pediatric population, an age range over which the pelvis undergoes tremendous structural change. We hypothesize that these structural changes influence pelvic fracture injury mechanisms. A probability sample of children under age 16 years in crashes were enrolled in an on-going crash surveillance system which links insurance claims data to telephone survey and crash investigation data. 15,725 children in side impact collisions were studied. Risk of pelvic fracture in side impact collisions was estimated and factors associated with these injuries were identified. Eight cases were examined using in-depth investigation to identify the injury mechanisms. Of our study sample, 0.10% of children suffered a pelvic fracture. The typical child with a pelvic fracture was a 12-15 year old female front row occupant of a passenger car involved in a struck side collision with intrusion.

On-site, in-depth investigations were conducted on 14 crashes involving 15 children who sustained facial fractures. Of the 23 facial fractures documented, the most frequent were the nose (n=8), orbit (n=6), zygoma/maxilla (n=6), and mandible (n=3). The most frequent contact point of those seated in the rear was the rear of the front seat; of those seated in the front, the instrument panel. 11/15 had sub-optimal torso restraint resulting from placing the shoulder belt behind their back or sitting in a position only equipped with a lap belt. The data suggest that these injuries resulted from high-energy impact with interior vehicle components. Revision to FMVSS 201 to account for vehicle interior structures typically contacted by child occupants and enhancement of pediatric dummies to measure facial impact forces should be considered.