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A detailed understanding of the size, shape, and postures of children is required to design effective restraint systems for protecting children in motor vehicle crashes. Compiled and edited by experts in the fields of anthropometry, ergonomics, and child restraint, this book includes 14 important papers which provide a comprehensive overview of the methods for collecting, analyzing, and applying child anthropometry data for crash safety purposes. A detailed understanding of the size, shape, and postures of children is required to design effective restraint systems for protecting children in motor vehicle crashes. Compiled and edited by experts in the fields of anthropometry, ergonomics, and child restraint, this book includes 14 important papers which provide a comprehensive overview of the methods for collecting, analyzing, and applying child anthropometry data for crash safety purposes.

In the mid 1970s, UMTRI investigated the biomechanical properties of the head and neck using 180 “normal” adult subjects selected to fill eighteen subject groups based on age (young, mid-aged, older), gender, and stature (short, medium, and tall by gender). Lateral-view radiographs of the subjects’ cervical spines and heads were taken with the subjects seated in a simulated automotive neutral posture, as well as with their necks in full-voluntary flexion and full-voluntary extension. Although the cervical spine and lower head geometry were previously measured manually and documented, new technologies have enabled computer digitization of the scanned x-ray images and a more comprehensive and detailed analysis of the variation in cervical spine and lower head geometry with subject age, stature, and gender. After scanning the radiographic images, 108 skeletal landmarks on the cervical vertebrae and 10 head landmarks were digitized.

A combination of finite element modeling and sled test reconstruction of real-world infant head injury scenarios has been used to investigate infant head impact response and tolerance to skull fracture. Studying the role of cranial sutures on infant skull response was of particular interest. The specific injury scenarios selected for reconstruction involved infants in rear-facing child restraint systems (CRS) who sustained skull fractures and brain injuries from deploying passenger-side frontal airbags. Approximations of the loading conditions for three injury cases, as well as estimates of loading conditions not expected to result in head injury, were produced in the laboratory. A finite element model (FEM) of a six-month-old infant head was developed using available material properties and humanlike geometry. The infant head FEM was used to simulate different injury and no-injury loading conditions based on CRS response data from the reconstruction tests.

This paper describes results from a survey of older children with respect to vehicle and booster restraints. The work first consisted of a rudimentary anthropometry study of 155 volunteers aged between 7 and 12 years. The data were compared to an extensive child anthropometry study conducted by the University of Michigan in 1975. Height and sitting height data matched well, while children in the current study appeared heavier. In the restraint fit survey, each child sat in the rear seat alone and in three belt-positioning booster seats (Volvo, Kangaroo, Century CR-3) in three vehicles (Ford Taurus, Pontiac Sunbird, Dodge Caravan). Booster seats greatly improved belt fit over the rear seat alone. The majority of children in this study had better belt fit with the boosters than with the rear seat alone, regardless of size. However, children who could fit well in the boosters and had good or fair belt fits were generally 36 kg or less.

A study of injury patterns of older children (aged 6-12 years) indicates that they may deserve more attention from automotive safety researchers. Although older children represent 43.1% of child occupants involved in accidents taken from the National Accident Sampling System (NASS) database, they receive 55.4% of the injuries suffered by children. A lower restraint usage rate (56.2% compared to 63.4% for younger children) partly accounts for this disproportionate amount of injury. However, when restrained, fewer older children remain uninjured compared to younger children (62.8% vs. 70.8%). The number of older children receiving injuries decreases with restraint use (63.6% injured for unrestrained vs. 37.5% injured for restrained). When comparing injuries to restrained and unrestrained older children, the injuries are generally the same severities, but restraints lead to higher proportions of pelvis/abdomen injuries while reducing the occurrence of whole body injuries.