Forward-facing Child Restraint Research Articles

Observed use of tethers in forward-facing child restraint systems

BackgroundUse of top tethers with forward-facing child restraints is a simple way for parents to keep their children safer when travelling in passenger vehicles, but tether use remains low.ObjectivesTo obtain...

Child safety analysis for forward-facing child restraint system in frontal impact

The objective of this paper is to investigate the design of a forward-facing child restraint system (CRS) and related vehicle components through the study of three-year-old children in frontal impact. In this research, the finite element (FE) model of a five-point harness child restraint system was developed and a three-year-old Hybrid III dummy in MADYMO format was used along with the extended coupling method with LS-DYNA and MADYMO. This paper specifically addresses the parametric study of a five-point harness CRS and LATCH (lower anchors and tethers for children) system for forward-facing CRS in frontal crashes. The parameters include a chest clip, lower anchor straps and a seat pad. Furthermore, a new LATCH type is suggested, in which supplementary webbing was considered. The influence of preloading condition of a harness on a child dummy was explored as well. These results demonstrate the feasibility of the improved safety by devising an appropriate CRS.

Load Limiting Behavior in CRS Tether Anchors as a Method to Mitigate Head and Neck Injuries Sustained by Children in Frontal Crash

Objective. This study focuses on methods to reduce injuries, specifically in the head and neck region, sustained by children seated in forward-facing child restraint system during a frontal vehicle crash. The main objective of this research was to implement load-limiting behavior into the upper tether and lower LATCH anchors of the CRS in order to reduce the neck injury criteria by increasing forward head excursion. Methods. Federal Motor Vehicle Safety Standard 213 outlines that the maximum limit for head excursion of the child dummy should be 720 mm, and the neck injury criteria should be less than 0.33 beyond the first 30 ms of the impact. Working within these limits, a fully deformable finite element model of a child restraint seat incorporating a Hybrid III 3-year-old dummy has been previously developed that has been validated for frontal impacts under CMVSS 208 and FMVSS 213 testing conditions. Observations from this previous work have illustrated that despite the head excursion being significantly less than the proposed limit of 720 mm, values of the neck injury criteria exceeded the protection reference values. Values of the load limits for both upper tether and lower LATCH anchors were calculated based on two approaches, initially based upon neck injury criteria and then an energy-based approach. Three numerical models were developed incorporating a Hybrid III 3-year-old dummy, Q3 child dummy, and a child finite element model. Numerical simulations, utilizing the identical 213 testing conditions, were completed incorporating load-limiting capabilities of the upper tether and lower LATCH anchors. Results. Evaluation of injury criteria based on the quantitative analysis of the simulations yielded that the implementation of load-limiting behavior in the upper tether and lower LATCH anchors was effective in reducing the head injury criteria by approximately 60 to 70%. Conclusion. Implementation of load-limiting behavior in the upper tether and lower LATCH anchors of the child restraint system effectively reduces the head and neck injuries sustained by toddlers in a frontal vehicle crash while controlling forward head excursion within the limits as defined by NHTSA.

A Computational Study of Rear-Facing and Forward-Facing Child Restraints

A Computational Study of Rear-Facing and Forward-Facing Child Restraints

Lower Extremity Injuries in Children Seated in Forward Facing Child Restraint Systems

Objective. The lower extremity is among the most frequently injured body regions for children restrained by forward facing child restraint systems (FFCRS), accounting for 28% of their clinically significant injuries, defined as AIS 2 and greater injuries excluding concussions. Despite the prevalence of these injuries, the current U.S. Motor Vehicle Safety Standard governing FFCRS (FMVSS 213) does not provide a direct assessment of the biomechanical risk of lower extremity fracture nor do the current pediatric test devices provide adequate instrumentation to detect the risk of such injuries. Before improvements can be made to the anthropometric test devices (ATDs) or test procedures to address these limitations, understanding of the sources and mechanisms of these injuries is necessary. Therefore, the objective of this study was to document location, source, and crash circumstances of lower extremity injuries in children seated in FFCRS. Methods. Utilizing two sources of data, PCPS and CIREN, 20 in-depth investigations of crashes involving children seated in FFCRS with lower extremity injuries were reviewed to determine the nature of the injuries and the circumstances under which they occurred. Results. Injuries below the knee were the most common, particularly to the tibia/fibula, and they most often occurred due to interaction with the vehicle seatback in front of the child's seating position. These injuries were sustained most commonly in frontal impacts although interaction with the seatback also occurred in other crash types. This interaction with the seatback was exacerbated by possible contributing factors such as intrusion of the front seatback into the child's occupant space or FFCRS misuse resulting in increased excursion of the child during impact. Conclusions. This review of cases of children in FFCRS with AIS 2 and greater lower extremity injury points to the role of the seatback in the occurrence of these injuries, suggesting the need to consider this interaction in the seatback design process and to adequately represent this interaction in regulatory procedures assessing the performance of child restraints.

Lower extremity injuries in children seated in forward facing child restraint systems

Lower extremity injuries in children seated in forward facing child restraint systems

Field Investigation of Child Restraints in Side Impact Crashes

Objective. Various test procedures have been suggested for assessing the protection afforded by child restraints (CRS) in lateral collisions. Analyses of real world crashes can be used to identify relevant characteristics of the child, restraint, collision, and injury mechanisms that should be incorporated into the design of the test procedures as well as in the design of related ATDs and injury metrics. The objective of this work is to use in-depth crash investigations of children restrained in CRS in side impacts to elucidate specific sources and mechanisms of injuries and explore the role of crash severity variables such as magnitude and location of intrusion and specific impact angle. Methods. Real world crashes involving children restrained in forward facing CRS in side impacts were analyzed from Partners for Child Passenger Safety, an on-going child specific crash surveillance system in which insurance claims are used to identify cases. In-depth crash investigations using standardized protocols were used to calculate the crash severity and determine the mechanisms and sources of the injuries sustained. Results. Cases of 32 children restrained in CRS in 30 side impact crashes were examined. Twenty-five percent sustained AIS 2+ injuries. The most common injuries sustained by children restrained in CRS in side impact crashes were to the face, head, and lower extremity. Characteristics of the crashes that appeared related to injury were intrusion that entered the child's occupant space or caused an interior part of the vehicle to enter the child's occupant space, forward component of the crash, and the rotation of the CRS, restrained by a seat belt, towards the side of the impact. Conclusions. The ability to assess the injury potential in a laboratory setting for the body regions of common injury, the head, face, and lower extremity, must be explored. Characteristics of a regulatory-based test procedure to assess injury risk should include a frontal component to the crash and intrusion into the occupant's seating position. Design enhancements of the CRS should address rotation during lateral impacts. These results provide guidance to current efforts to design and regulate these restraints for the safety of child passengers in side impacts.

Cervical Spine Injuries in Children Restrained in Forward-Facing Child Restraints: A Report of Two Cases

Cervical Spine Injuries in Children Restrained in Forward-Facing Child Restraints: A Report of Two Cases

Improved Protection for Children in Forward-Facing Restraints During Side Impacts

Objective:This study aims to determine the potential for improved child occupant protection in side impacts that can be obtained using rigid and semi-rigid anchorage systems and the addition of energy-absorbing padding in the side structures of child restraints. Methods:This study uses a comprehensive set of simulated side impacts to evaluate the potential for improved side impact protection in forward-facing child restraints. Factors investigated included methods of anchoring the restraint to the vehicle, energy-absorbing materials in the side structure of restraints, and design features of the restraints such as side wing geometry and seat belt routing. Results:The results show clearly that completely rigid lower attachment of restraints offers the potential for great reductions in head injury risk, which anchorage systems employing a combination of a rigid anchorage bar and webbing attached to a child restraint cannot match. The addition of energy absorbing material in the side structure of restraint systems is effective when the head is fully contained within an adequately designed side wing structure. For restraints anchored by seat belts and loop style semi rigid anchorage straps, belt routing has the potential to significantly affect occupant head excursion. Conclusions: The results suggest that current child restraint standards and consumer testing protocols do not adequately encourage best practice design of child restraints for side impact protection.

An evaluation of the effectiveness of forward facing child restraint systems

The objective of this study was to determine the effectiveness of forward facing child restraint systems (FFCRS) in preventing serious injury and hospitalization to children 12–47 months of age as compared with similar age children in seat belts. Data were obtained from a cross-sectional study of children aged 12–47 months in crashes of insured vehicles in 15 states, with data collected via insurance claims records and a telephone survey. Effectiveness estimates were limited to those children between 12 and 47 months of age seated in the back row(s) of vehicles, restrained in FFCRS, regardless of misuse, or seat belts of all types and usage. Completed survey information was obtained on 1207 children, representing 12,632 children in 11,619 crashes between 1 December 1998 and 31 May 2002. Serious injuries occurred to 0.47% of all 12–47-month olds studied, including 1.72% of those in seat belts and 0.39% of those in child restraint systems. The risk of serious injury was 78% lower for children in FFCRS than in seat belts (odds ratio (OR)=0.22, 95% confidence interval (CI)=0.11–0.45, P<0.001). The risk of hospitalization was 79% lower for children in FFCRS than in seat belts (OR=0.21, 95% CI=0.09–0.50, P=0.001). There was no difference between the restraint types in preventing minor injuries. As compared with seat belts, CRS are very highly effective in preventing serious injuries and hospitalization, respectively. This effectiveness estimate is substantially higher than older estimates, demonstrating the benefits of current CRS designs. These results provide those educating parents and caregivers population-based data on the importance of child restraint use.