A study of injury parameters for rearward and forward facing 3-year-old child dummy using numerical simulation

Abstract

More children die of road traffic injuries than of any other cause. Nonuse and misuse of child restraints is common and leads to preventable severe injuries or deaths. Furthermore, many children graduate to inappropriate restraint systems or switch from rearward to forward facing prematurely. Facing rearward is intrinsically safer, provided the head is supported, and the reasons for seating a child in the opposite position relate to convenience, not safety. With heavy heads and weak necks, children are vulnerable to catastrophic traction injuries to the cervical cord, and children older than 1 year retain this vulnerability. Most studies have estimated that rearward facing restraints reduce the risk of serious injury by about 80–90%. A recent analysis of the Swedish Volvo crash database reported that the injury reducing effect of rearward facing child restraints might be as high as 96%. However, the age at which children should start sitting in a forward-facing position is controversial. The American Academy of Pediatrics has recently advised that children should be seated facing the rear of the vehicle for as long as possible and at least until 1 year of age. Both Transport Canada and the US National Highway Traffic Safety Administration (NHTSA) currently suggest having children face forward from about 1 year of age or once they reach 10 kg (22 lb), while Australian children are often turned around to forward facing at 5 to 6 months of age. In this paper a multi-body dynamic simulation MADYMO model is developed for rearward and forward facing 3-year-old child dummy. The reasonable correlation between the developed forward facing numerical simulation results and the experimental results indicates that the model is robust. Simulation for both facing configurations is conducted using an experimental moderate frontal crash pulse. The study indicates that the upper neck forces, and the neck injury criteria can be greatly reduced by keeping the child in the rearward facing position. For children safety, parents and caregivers should seriously consider keeping children rearward facing for as long as possible. Moreover, manufacturers should be encouraged to develop car safety seats that accommodate children rear facing up to 4 years of age.