Forward-facing Child Safety Seats Research Articles

Applying basic principles of child passenger safety to improving transportation safety for children who travel while seated in wheelchairs

Occupant restraint systems are designed based on knowledge of crash dynamics and the application of proven occupant-protection principles. For ambulatory children or children who use wheelchairs but can transfer out of their wheelchair when traveling in motor vehicles, there is a range of child safety seats that comply with federal safety standards and that therefore offer high levels of crash protection. For children who remain seated in wheelchairs for travel, the use of wheelchairs and wheelchair tiedown and occupant restraint systems (WTORS) that comply with voluntary industry standards significantly enhances safety. Revisions to the initial versions of these standards will further improve safety for smaller children who travel seated in wheelchairs by requiring wheelchairs for children between 13 and 22 kg (18 and 50 lb) to provide a five-point, wheelchair-integrated crash-tested harness similar to that used in forward-facing child safety seats. While wheelchair and tiedown/restraint manufacturers, van modifiers, transportation personnel, clinicians, and others involved with children who use wheelchairs have clearly defined responsibilities relative to providing these children with safe transportation, parents and caregivers should be knowledgeable about best-practice in wheelchair transportation safety and should use this knowledge to advocate for the safest transportation possible.

Countermeasures to mitigate head and neck injuries to toddlers in frontal and lateral vehicle crash conditions

This study focuses on methods to reduce injuries, specifically in the head and neck region, sustained by children seated in forward-facing child safety seats during a vehicle crash. A fully deformable finite element model (FEM) of a child restraint seat incorporating a Hybrid III 3-year-old dummy has previously been developed which has been validated for frontal impacts under CMVSS 208 and FMVSS 213 testing conditions, and near-side impacts under ANPRM (FMVSS 213) norms. Observations from this previous work have illustrated higher values of neck forces and moments sustained by the dummy's neck. The main objective of this research was to develop a head and neck restraining device in order to limit the forward and lateral head movement/rotation of the child. The head and neck safety device comprised two parts, namely the collar and the tether. The collar was restrained to the dummy's torso with the seatbelt and the tether was constrained to the dummy's head. In addition, the effect of using a cross-shaped rigid ISOFIX system was also investigated. Three numerical models were developed incorporating a Hybrid III 3-year-old dummy, Q3/Q3s child dummies and a child FEM. Numerical simulations were completed in frontal, near-side and a 45° impact situation in accordance with the FMVSS 213 norms in the absence and presence of the head and neck safety device, for both the flexible LATCH and the cross-shaped rigid ISOFIX system. Evaluation of injury criteria based on the quantitative analysis of the simulations yielded that the head and neck device in conjunction with the rigid ISOFIX system was effective in reducing the resultant upper neck forces by approximately 40 to 75% for all the child models under different impact conditions. In addition, the head injury criterion was observed to be reduced by approximately 45 to 65% for all the impact conditions. Presence of the head and neck device effectively reduced the head excursions for all the impact conditions. In addition, the cross-shaped rigid ISOFIX further decreased the CRS displacement in both the forward and lateral directions. The forward and lateral displacement of the centre of mass of the head was observed to be reduced by approximately 30 to 50% for different impact conditions. Greater amount of bending in both the lateral and forward directions was observed for the Q3/Q3s dummies and the child FE model. This can be attributed to lower degree of stiffness and geometrical differences in the Q3/Q3s dummy's neck, which make the neck more flexible.

Methods to mitigate injury to toddlers in near-side impact crashes

This research focuses on the injury potential of children seated in forward-facing child safety seats during side impact crashes in a near-side seated position. Side impact dynamic sled tests were conducted by NHTSA at Transportation Research Center Inc. (TRC) using a Hybrid III 3-year-old child dummy seated in a convertible forward/rearward child safety seat. The seat was equipped with a LATCH and a top tether and the dummy was positioned in forward-facing/near-side configuration. The test was completed using an acceleration pulse with a closing speed of 24.1 km/h, in the presence of a rigid wall and absence of a vehicle body. A fully deformable finite element model of a child restraint seat, for side impact crash investigations, has been developed which has also been previously validated for frontal and far side impacts. A numerical model utilizing a Hybrid III 3-year-old dummy, employing a similar set-up as the experimental sled test was generated and simulated using LS DYNA. The numerical model was validated by comparing the head and the chest accelerations, resultant upper and lower neck forces and moments from the experimental and numerical tests. The simulation results were observed to be in good agreement to the experimental observations. A numerical model of the near-side laboratory tests, utilizing a Q3s child dummy, was also created for parametric studies regarding different ISOFIX configurations. Further, numerical simulations were completed for both the dummy models with rectangular and cross-shaped sections of rigid ISOFIX systems. In addition, studies were conducted to confine lateral movement of the dummy's head by adding energy absorbing foam on the side wings in the vicinity of the contact region of the CRS. It was observed that the use of rigid ISOFIX system reduced the lateral displacement of the CRS and different injury parameters. Addition of energy absorbing foam blocks was effective in further reducing the lateral displacement of the dummy's head. The lateral displacement of the head was reduced by 68 mm by using cross-shaped section ISOFIX with energy absorbing foam near the vicinity of the head of the Hybrid III 3-year-old dummy compared to the flexible LATCH configuration without foam. For the Q3s dummy, the lateral displacement of the head was reduced by 48 mm by utilizing a cross-shaped section rigid ISOFIX system with the addition of energy absorbing foam compared to the flexible LATCH configuration.

Evaluation of child safety seat checkpoint events

Objective To determine the effectiveness of child safety seat checkpoints in generating change in child restraint practice to reduce the prevalence and extent of misuse. Methods Child safety seats underwent an initial checkpoint evaluation and participants received a training session. Participants were asked to return within 6–12 months to a checkpoint for follow-up evaluation. During each visit, a data collection sheet was used to assess the participants’ use of their child safety seat, and to subsequently calculate a restraint misuse score to characterize the child safety seat's usage before and after the intervention. Results During the period of study, 42 participants underwent both the initial and follow-up child safety seat check. Before the intervention, at least one misuse was identified in 100% of installed child safety seats. After the intervention, there was a significant reduction in the proportion of rear-facing child safety seats (18.8%) and forward-facing child safety seats (64.0%) that had at least one misuse ( p < 0.001). Almost all (93.4%) of those using rear-facing child safety seats and the majority (64.0%) of those using forward-facing child safety seats improved their safety score as measured after the intervention. Conclusions Although misuse was universally observed, child safety seat checkpoint events were successful in improving usage practices.

The appropriate and inappropriate use of child restraint seats in Manitoba

The objective of this research was to describe the use and incorrect use of child restraint systems in Manitoba, Canada. In 2004, a team of inspectors made up of Royal Canadian Mounted Police officers and trained car seat technicians from the Manitoba child seat coalition conducted a descriptive survey of types and frequency of child restraint systems' incorrect use. The setting was 10 roadside inspection sites located around the city of Winnipeg, Manitoba. The subjects were parents and primary caregivers of children using child restraint systems. The main outcome measured was the reported appropriate use rate as determined by the compliance to safety standards for correct installation and use of child restraints. A total of 340 child restraint systems were assessed. The overall rate of incorrect use was 70%. The errors present in stage III systems (booster seats) are much lower than the errors present in stage I systems (rear-facing child safety seats) and stage II systems (forward-facing child safety seats). The data presented illustrate that incorrect use of child restraint systems in the province of Manitoba is a large problem and must be dealt with immediately in order to ensure child safety now and in the future. Community-wide information and enhanced enforcement campaigns, consisting of activities such as mass media, information and publicity, child restraint systems displays and special enforcement strategies (check points, dedicated law enforcement officials, alternative penalties) should be used to increase the correct use of child restraint systems. Failure to use child restraint systems properly can contribute to serious injury or death of a child.

Child restraint seat design considerations to mitigate injuries to three-year-old children in side impact crashes

This research focuses on the injury potential of children seated in forward-facing child safety seats during side impact crashes in a far-side seated position. Side impact dynamic sled tests were conducted by Transportation Research Center Inc. (TRC) using two Hybrid III 3-year-old child dummies in convertible forward/rearward child safety seats. The seats were equipped with a LATCH and a top tether and the dummies were positioned in forward-facing/far-side configuration. The tests were completed using an acceleration pulse with a closing speed of 32.8 km/h, and the seat fixture with vehicle body oriented at 270° relative to the motion of the sled. A fully deformable finite element model of a child restraint seat, for side impact crash investigations, has been developed which has also been previously validated for frontal impacts. A numerical model employing a similar set-up as the experimental sled test was generated and simulated using LSDYNA. The numerical model was validated by comparing the head and the chest accelerations, resultant upper and lower neck forces and moments from the experimental and numerical tests. The simulation results were observed to be in good agreement to the experimental observations. Further studies were conducted to confine lateral movement of the dummy's head by adding energy absorbing foam on the side wings in the vicinity of the contact region of the CRS. It was observed from the simulation results that the addition of foam padding and foam blocks was effective in reducing the head injury criteria of the Hybrid III 3-year-old dummy by approximately 30%, and the upper neck lateral shear and lateral bending by approximately 45%.

Effect of Booster Seat Laws on Appropriate Restraint Use by Children 4 to 7 Years Old Involved in Crashes

To quantify the independent contribution of recently enacted booster seat laws on appropriate restraint use by child passengers in motor vehicles. Longitudinal study of children involved in crashes with data collected via insurance claims records and a validated telephone survey. Sixteen states and Washington, DC, from December 1, 1998, through December 31, 2004. Probability sample of 5198 vehicles in crashes involving 6102 children aged 4 to 7 years, representing 78 159 vehicles and 91 752 children. Booster seat law provisions, child age, state, and secular trends. Reported appropriate restraint use for this age group, including forward-facing child safety seats, belt-positioning booster seats, and combination seats. Children aged 4 to 7 years in states with booster seat laws were 39% more likely to be reported as appropriately restrained than were children in other states (prevalence ratio [PR], 1.39; 95% confidence interval [CI], 1.14-1.70). Children aged 4 to 5 years were 23% more likely (PR,1.23; 95% CI, 0.80-1.42) and children 6 to 7 years twice as likely (PR, 2.09; 95% CI, 1.46-2.99) to be reported as appropriately restrained. For children aged 6 to 7 years, when compared with no law, laws through age 7 years were most effective (PR, 3.71; 95% CI, 2.49-5.42), followed by laws through age 4 or 5 years (PR, 1.43; 95% CI, 0.89-2.24). Given the higher current use of age-appropriate restraints among children 4 to 5 years compared with older children, future upgrades to child restraint laws should include children through at least age 7 years to maximize the number of children properly restrained for their age.

Parent Driver Characteristics Associated with Sub-Optimal Restraint of Child Passengers

Objectives. To identify parent driver demographic and socioeconomic characteristics associated with the use of sub-optimal restraints for child passengers under nine years. Methods. Cross-sectional study using in-depth, validated telephone interviews with parent drivers in a probability sample of 3,818 vehicle crashes involving 5,146 children. Sub-optimal restraint was defined as use of forward-facing child safety seats for infants under one or weighing under 20 lbs, and any seat-belt use for children under 9. Results. Sub-optimal restraint was more common among children under one and between four and eight years than among children aged one to three years (18%, 65%, and 5%, respectively). For children under nine, independent risk factors for sub-optimal restraint were: non-Hispanic black parent drivers (with non-Hispanic white parents as reference, adjusted relative risk, adjusted RR = 1.24, 95% CI: 1.09–1.41); less educated parents (with college graduate or above as reference: high school, adjusted RR = 1.27, 95% CI: 1.12–1.44; less than high school graduate, adjusted RR = 1.36, 95% CI: 1.13–1.63); and lower family income (with $50,000 or more as reference: <$20,000, adjusted RR = 1.23, 95% CI: 1.07–1.40). Multivariate analysis revealed the following independent risk factors for sub-optimal restraint among four-to-eight-year-olds: older parent age, limited education, black race, and income below $20,000. Conclusions. Parents with low educational levels or of non-Hispanic black background may require additional anticipatory guidance regarding child passenger safety. The importance of poverty in predicting sub-optimal restraint underscores the importance of child restraint and booster seat disbursement and education programs, potentially through Medicaid.

Child passenger safety for inner-city Latinos: new approaches from the community

Objective: Motor vehicle crashes injuries, the leading cause of death for Latino children in the United States, can be reduced by the correct use of child safety seats. This study...

Critical Gaps in Child Passenger Safety Practices, Surveillance, and Legislation: Georgia, 2001

Motor vehicle crashes remain the leading cause of death among US children 1 year of age and older. Although age-appropriate child passenger restraint use and back seating position are effective injury prevention strategies, many children 12 years of age and younger ride inappropriately restrained and seated in the front seat. In Georgia and in most states, surveillance of child passenger restraint use is less than optimal. Although child safety seat legislation is 1 of the most effective mechanisms for increasing correct restraint use and back seating position, Georgia's child occupant restraint law, like the laws in most states, falls short of practices recommended by government and child advocacy safety groups. The objective of this study was to document child passenger restraint use and seating position among children aged 0 to 12 years in Georgia and to use these study results to evaluate the efficacy of Georgia's child restraint surveillance and legislation. In May and June 2001, police roadblocks were used to collect information about child passenger age, restraint use, and seating position. Data were collected on 1858 children who were riding in 1221 vehicles in 24 different Georgia counties. Results showed that 56% of children were inappropriately restrained and/or in the front seat. The most problematic age groups included infants who were in forward-facing child safety seats (28%) and/or in the front seat (22%); children who were 5 to 8 years of age in car seat belts alone (88%), rather than age- and size-appropriate child safety seats (6%); and children who were 9 to 12 years of age and riding in the front seat (39%). We compared our results with the existing Georgia passenger restraint surveillance system and found that it would have missed 77% of the children in our study who were inappropriately restrained and/or riding in the front seat. In a similar comparison, Georgia's restraint law did not cover over 74% of the children in our study who were riding at risk. The results of this study highlight 3 important areas for improving child passenger safety: targeted interventions to promote booster seat use and riding in the back seat, expanded child passenger restraint and seating position surveillance, and expanded legislation to mandate booster seat use and back seating position.