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Objective: Optimal child passenger protection requires use of a restraint designed for the age/size of the child (appropriate use) that is used in the way the manufacturer intended (correct use).This study aimed to determine child restraint practices approximately 10 years after introduction of legislation requiring correct use of age-appropriate restraints for all children aged up to 7 years., Methods: A stratified cluster sample was constructed to collect observational data from children aged 0-12 years across the Greater Sydney region of New South Wales (NSW). Methods replicated those used in a similar 2008 study. Population weighted estimates for restraint practices were generated, and logistic regression used to examine associations between restraint type, and child age with correct use accounting for the complex sample., Results: Almost all children were appropriately restrained (99.3%, 95% CI 98.4% to 100%). However, less than half were correctly restrained (no error=27.3%, 95% CI 10.8% to 43.8%, no serious error=43.8%, 95% CI 35.0% to 52.7%). For any error, the odds of error decreased by 39% per year of age (OR 0.61, 95% CI 0.46 to 0.81) and for serious error by 25% per year (OR 0.75, 95% CI 0.60 to 0.93)., Conclusion: The findings demonstrate high levels of appropriate restraint use among children across metropolitan Sydney approximately 10 years after introduction of legislation requiring age-appropriate restraint use until age 7, however, errors in the way restraints remain common., Implications for Public Health: Given the negative impact incorrect use has on crash protection, continuing high rates of incorrect use may reduce effectiveness of legislative change on injury reduction., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Many children with physical disabilities need additional postural support when sitting and supplementary padding is used on standards approved child restraints to achieve this when traveling in a motor vehicle. However, the effect of this padding on crash protection for a child is unknown. This study aimed to investigate the effect of additional padding for postural support on crash protection for child occupants in forward facing child restraints., Methods: Forty frontal sled tests at 49 km/h were conducted to compare Q1 anthropometric test device (ATD) responses in a forward-facing restraint, with and without additional padding in locations to increase recline of the restraint, and/or support the head, trunk and pelvis. Three padding materials were tested: cloth toweling, soft foam, and expanded polystyrene (EPS). The influence of padding on head excursion, peak 3 ms head acceleration, HIC15, peak 3 ms chest acceleration and chest deflection were analyzed., Results: The influence of padding varied depending on the location of use. Padding used under the restraint to increase the recline angle increased head injury metrics. Toweling in multiple locations which included behind the head increased head excursion and chest injury metrics. There was minimal effect on injury risk measures with additional padding to support the sides of the head or the pelvis position. Rigid EPS foam, as recommended in Australian standards and guidelines, had minimal effect on injury metrics when used inside the restraint, as did tightly rolled or folded toweling secured to the restraint at single locations around the body of the child., Conclusions: This study does not support the use of postural support padding to increase recline of a forward-facing restraint or padding behind the head. Recommendations in published standards and guidelines to not use foam that is spongy, soft or easily compressed, with preference for secured firm foam or short-term use of tightly rolled or folded toweling under the child restraint cover is supported. This study also highlights the importance of considering the whole context of child occupant protection when using additional padding, particularly the change in the child's seated position when adding padding in relation to the standard safety features of the restraint.

Objective: To compare characteristics and restraint use between a population-based and fitting service sample of child restraint users., Method: Characteristics of the two samples were compared using chi-squared tests. Differences in errors in restraint use observed in the two samples were modeled using logistic regression., Results: There were significant differences in child age ( p  < 0.001), and restraint types ( p  < 0.001) between the two samples, with more younger children in the fitting service sample. Controlling for differences in restraint type, the odds that adult participants were female were 61% less in the fitting service sample than in the population-based sample (OR 0.39, 95%CI 0.21-0.71). The odds that adult participants perceived a large risk associated with restraint misuse (OR 3.62, 95%CI 1.33-9.84), had a household income in the highest bracket (OR 3.89, 95%CI 1.20-12.62) and were living in areas of highest socioeconomic advantage (OR 2.72, 95%CI 1.22-6.06) were approximately three times higher in the fitting service sample. Overall, more participants had errors in restraint use in the population-based sample ( p  = 0.021). However, after controlling for restraint type, securing errors were three times more likely (OR 3.34, 95%CI 1.12-10.2), and serious installation errors were almost twice as likely (OR 1.91, 95% CI 1.09-3.39) in the fitting service sample., Conclusions: While less resource intensive, convenience and/or fitting service samples may be less representative than population-based samples. Given the need for efficiency, methods that combine randomized population-based invitations to participate in restraint fitting check day events across geographically representative areas may be useful for ongoing surveillance of child restraint use.

Objectives: Ergonomic design of child restraint systems (CRS) may facilitate optimal travel behavior and crash protection of child passengers during motor vehicle trips. However there have been few studies examining the relationship between CRS design and child passenger travel behavior. The aim of this study was to examine whether associations between CRS design features and child passenger behavior exist during real-world, everyday vehicle trips., Methods: Video from a naturalistic driving study (NDS) was analyzed in this study. Families drove an instrumented study vehicle for approximately two weeks with at least one child aged between one and eight years traveling in their own forward-facing (FF) CRS or belt positioning booster (BPB). Video for one child passenger was randomly selected from each trip for analysis. Video was coded for five-second epochs at nine time points (5%, 17%, 25%, 30%, 50%, 53%, 75%, 89% and 95% of trip length). Two types of child passenger travel behaviors were identified by manual review of the video and audio recordings: (i) optimal/suboptimal head position and (ii) correct/incorrect use of the internal harness/shoulder belt. Video screenshots were used to characterize CRS design features. Random effects logistic regression models were used to examine the associations between specific CRS design features and the travel behaviors of interest, whilst accounting for clustering of data by child and trip., Results: Suboptimal head position was associated with the absence of a height adjustable headrest and a narrow headrest wing width in FFCRS. Incorrect harness use in a FFCRS was associated with the absence of an adjustable headrest, in addition to headrest features such as wing width and depth. In BPBs, a reduction in suboptimal head position was associated with the absence of a sash belt guide, however no restraint design features were associated with incorrect shoulder belt use., Conclusions: Some CRS design features may influence undesirable child passenger travel behavior. These early findings support enhanced and user-centric CRS design as a likely important mechanism to improve child passenger safety.

Objective: To compare how errors in child restraint use influence crash injury risk in rearward and forward-facing restraints for a 1-year old occupant., Methods: Three convertible child restraint systems (CRS) were subjected to frontal dynamic sled tests at 56 km/h in rearward-facing and forward-facing modes in a correct use (baseline) condition and in five incorrect use conditions: loose securing belt, loose harness, partial harness use, top tether slack, and three minor errors. Excursion, head, and chest 3 ms resultant acceleration, HIC15, and neck forces and moments of a Q1 anthropomorphic test device (ATD) seated in the restraints were measured. The effect of incorrect use on each outcome and restraint type was analyzed., Results: The influence of errors varied across different outcome variables, the three restraints tested and orientation modes. Excursion increased in four of five incorrect use conditions in both rearward and forward-facing orientations. A very loose harness increased four of five outcome variables in at least one forward-facing restraint, whereas only excursion was increased when rearward-facing. Overall, there tended to be a more negative effect of incorrect use (demonstrated through increases in outcome variables compared to the baseline) in the forward-facing orientation., Conclusions: Overall, errors in use tended to have a larger negative impact on forward-facing restraints than rearward-facing restraints. Given the widespread nature of errors in use, this adds further weight to arguments to keep children rearward-facing to 12 months of age and older. The results also highlight a variation in response to errors across differently designed restraints, suggesting the influence of errors may be minimized by restraint design that is more resistant to errors.

Objective: It is often assumed that a child restraint with a five or six-point internal harness provides greater protection for children in frontal crashes than a booster seat with a lap-sash seat belt. However, most research comparing these restraint types has focused on protection for children aged up to approximately 3-4 years of age. Recently, harnessed child restraints for older children up to approximately 8 years of age have become available, but there is little data on their performance compared to booster seats for children over 4 years of age. This study aimed to compare frontal crash performance of a series of harnessed child restraints for children aged 4-8 years to booster seats., Methods: Four large harnessed child restraints (Type G in the Australian Standard, AS/NZS 1754:2013) and six high back booster seats (Type E in AS/NZS 1754:2013) were tested in frontal impact on a deceleration sled. Head and pelvis accelerations were recorded and head excursions were measured from high speed video., Results: Head excursion was an average of 92 mm greater in the large harnessed child restraints than the high back booster seats. The initial position of the head in Type G restraints, an average of 58 mm further forward compared to Type E boosters, was the main contributor to the larger head excursion during impact. Conversely, peak head accelerations in the impact phase were, on average, 37.2 g lower in the large harnessed child restraints than the high back booster seats., Conclusions: These data suggest that recommendations for harnessed restraints and booster seats for children aged 4-8 years is not as obvious as is sometimes assumed. Harnessed restraints allow greater head excursion in frontal impacts, potentially increasing the chances of head impacts, especially in vehicles with limited clearance between the restraint and the seat in front. The likelihood, and types of, incorrect use that occur in each restraint type, the vehicle occupant space, and the restraint's crash performance under ideal conditions should be considered in recommending restraints for these older children.

Objective: To examine the effect of age on the dynamic performance of child restraint systems in frontal crashes., Methods: A sample of used (3-269 months from manufacture) and newly purchased child restraints were subjected to frontal crash simulations of more than 56 km/h and peak deceleration approximately 33 g on a deceleration sled. Restraints were monitored for evidence of damage before and after each impact. Anthropometric test device (ATD) head and chest responses and peak head excursions were recorded for rearward facing restraints using the Q1 ATD and for forward facing restraints and booster seats using the Q6 ATD. The influence of restraint age on peak 3 ms head acceleration, HIC15, head excursion, peak 3 ms chest acceleration and restraint damage were analyzed., Results: In all impacts, the ATD remained within the restraint and secured to the test bench demonstrating the crash protection offered by the old and used restraints. There was no apparent relationship between ATD responses and restraint age for any restraint type. Older forward facing restraint systems had a very modest increase in forward head excursion (R 2 = 0.59, p = 0.001) of 0.27 mm for each month of age (95% CI, 0.13 mm - 0.42 mm). This equates to a 0.7% increase in the minimum measured excursion per year of restraint age. There was also a small increased likelihood of critical damage to the restraints in the simulated crashes per month of restraint age (OR 1.031, 95% CI 1.010-1.069)., Conclusions: Overall, degradation in restraint dynamic performance in older restraints, including some that are much older than the currently recommended 10-year lifetime, is minimal. However newer restraints may provide better protection due to marginal improvements in restraint design over time. Furthermore, the results of this study confirm previous recommendations that restraints should not be re-used after crash involvement.

Background: Incorrect use of child restraints is a long-standing problem that increases the risk of injury in crashes. We used user-centred design to develop prototype child restraint instructional materials. The objective of this study was to evaluate these materials in terms of comprehension and errors in the use of child restraints. The relationship between comprehension and errors in use was also explored., Methods: We used a parallel-group randomised controlled trial in a laboratory setting. The intervention group (n=22) were provided with prototype materials and the control group (n=22) with existing instructional materials for the same restraint. Participants installed the restraint in a vehicle buck, secured an appropriately sized mannequin in the restraint and underwent a comprehension test. Our primary outcome was overall correct use, and our secondary outcomes were (1) comprehension score and (2) percent errors in the installation trial., Results: There was 27% more overall correct use (p=0.042) and a higher mean comprehension score in the intervention group (mean 17, 95% CI 16 to 18) compared with the control group (mean 12, 95% CI 10 to 14, p<0.001). The mean error percentage in the control group was 23% (95% CI 16% to 31%) compared with 14% in the intervention group (95% CI 8% to 20%, p=0.056). For every one point increase in comprehension, there was an almost 2% (95% CI -2.7% to -1.0%) reduction in errors (y=45.5-1.87x, p value for slope <0.001)., Conclusions: Consumer-driven design of informational materials can increase the correct use of child restraints. Targeting improved comprehension of informational materials may be an effective mechanism for reducing child restraint misuse., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

The incorrect use of child car seats is common, with significant negative effects on crash protection for child passengers. There is currently little evidence for effective, practical countermeasures for incorrect use. The provision of clear and comprehensible materials on correct use supplied with restraints at the point of sale could be highly cost-effective and achieve similar benefits to restraint-fitting services or hands-on training; however, routinely supplied instructions in their current form are frequently difficult to understand. We are conducting a randomised controlled trial of the consumer-driven redesign of instructional materials, consisting of an instruction sheet, swing tags and online training videos. This paper presents the protocol that will be used in an innovate process evaluation that will use the primary outcome of overall serious misuse assessed at six months, together with a survey and semi-structured interviews to determine fidelity, dose and outcomes for all intervention participants. The study will assess intervention delivery and external factors that may impact the effectiveness of the intervention, including experience, health literacy, confidence and attitudes. When it has been conducted, this process evaluation will provide enhanced understanding of the mechanisms through which the intervention works or not, aspects of the implementation process key to success of the intervention and insight into how external factors influence the success of the intervention.

Background: With long-standing and widespread high rates of errors in child restraint use, there is a need to identify effective methods to address this problem. Information supplied with products at the point of sale may be a potentially efficient delivery point for such a countermeasure. The aim of this study is to establish whether product materials developed using a consumer-driven approach reduce errors in restraint use among purchasers of new child restraint systems., Methods: A cluster randomised controlled trial (cRCT) will be conducted. Retail stores (n=22) in the greater Sydney area will be randomised into intervention sites (n=11) and control sites (n=11), stratified by geographical and socioeconomic indicators. Participants (n=836) will enter the study on purchase of a restraint. Outcome measures are errors in installation of the restraint as observed by a trained researcher during a 6-month follow-up home assessment, and adjustment checks made by the parent when the child is placed into the restraint (observed using naturalistic methods). Process evaluation measures will also be collected during the home visit. An intention-to-treat approach will be used for all analyses. Correct use and adjustment checks made by the parent will be compared between control and intervention groups using a logistic regression model. The number of installation errors between groups will be compared using Poisson regression., Discussion: This cRCT will determine the effectiveness of targeted, consumer-driven information on actual error rates in use of restraints. More broadly, it may provide a best practice model for developing safety product information., Trial Registration Number: ACTRN12617001252303p; Pre-results., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2019. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: Cross-chest clips are widely used in North American child restraints but are less common in other countries, partially due to concerns over anterior neck contacts in frontal crashes. They have recently been reported to be associated with lower odds of injury in real-world crashes, but there is a paucity of crash test performance information. This study aimed to compare the dynamic performance of a small child occupant in frontal crash tests with and without cross-chest clips in place. Methods: Frontal sled tests at 49 km/h were conducted to compare 2 cross-chest clip designs to nonuse of a chest clip. Tests using a P3/4 anthropomorphic test device (ATD) to represent the smallest occupant in a forward-facing child restraint were conducted with the chest clips in the recommended position and also in an incorrect lower position and with and without additional harness slack present. Results: Though contacts were observed between the chest clips and the base of the ATD's neck, there was little difference observed in head excursion or ATD sensor loads in the presence of the chest clips. No detectable change in the neck forces or moments was detected at the time of the neck contacts. The position of the clips did not affect the results. Harness slack increased head excursion, as expected, but this effect did not differ between the tests with and without the clips. Conclusions: Cross-chest clips do not appear to greatly influence the dynamic performance of a forward-facing child restraint in a simulated frontal crash. Taken together with recent research suggesting a potential benefit in injury reduction from the clips in the real world, possibly due to maintaining the harness straps in place on a child's shoulders, it may be appropriate to re-evaluate safety standards that prevent their use.

Objective: Traffic crashes have high mortality and morbidity for young children. Though many specialized child restraint systems improve injury outcomes, no large-scale studies have investigated the cross-chest clip's role during a crash, despite concerns in some jurisdictions about the potential for neck contact injuries from the clips. This study aimed to investigate the relationship between cross-chest clip use and injury outcomes in children between 0 and 4 years of age., Methods: Child passengers between 0 and 4 years of age were selected from the NASS-CDS data sets (2003-2014). Multiple regression analysis was used to model injury outcomes while controlling for age, crash severity, crash direction, and restraint type. The primary outcomes were overall Abbreviated Injury Score (AIS) 2+ injury, and the presence of any neck injury., Results: Across all children aged 0-4 years, correct chest clip use was associated with decreased Abbreviated Injury Scale (AIS) 2+ injury (odds ratio [OR] = 0.44, 95% confidence interval [CI], 0.21-0.91) and was not associated with neck injury. However, outcomes varied by age. In children <12 months old, chest clip use was associated with decreased AIS 2+ injury (OR = 0.09, 95% CI, 0.02-0.44). Neck injury (n = 7, all AIS 1) for this age group only occurred with correct cross-chest clip use. For 1- to 4-year-old children, cross-chest clip use had no association with AIS 2+ injury, and correct use significantly decreased the odds of neck injury (OR = 0.49; 95% CI, 0.27-0.87) compared to an incorrectly used or absent cross-chest clip. No serious injuries were directly caused by the chest clips., Conclusions: Correct cross-chest clip use appeared to reduce injury in crashes, and there was no evidence of serious clip-induced injury in children in 5-point harness restraints.

Objective: Misuse of child restraint systems is a widespread and long-standing problem impacting risk of injury and death in car crashes. Discomfort has been suggested as a causative factor for misuse, particularly in errors introduced by children while they use the restraints. However, the relationship between comfort and errors in use has never been studied. In this study we examine the reliability and sensitivity of a newly developed observational method for assessing comfort in children in vehicles. We then use this method to examine the relationship between comfort and errors in use of booster seats., Methods: A novel method was developed for assessing comfort by counting fidgeting and postural adjustment behaviors to derive a Discomfort Avoidance Behavior (DAB) score. The sensitivity of the DAB score was examined by observing children in four different seating conditions designed as "comfortable" and "uncomfortable" (Part 1). Paired-samples t-tests were used to compare differences in DAB between seating conditions. The reliability of the DAB score was assessed by calculating the intraclass correlation coefficient (ICC) between DAB scores recorded by different researchers. The association between comfort and correctness of use was examined by observing children using booster seats (Part 2). The association between DAB score and number of usage errors was tested using linear regression analysis. Participants were children ages 4-8 years. Fourteen children participated in Part 1 and 15 children in Part 2., Results: The DAB score was sensitive to changes in seat condition (p < 0.01), and was repeatable between different researchers (ICC 0.98, 95% confidence interval [CI] 0.954-0.991). Increases in DAB were associated with increases in the number of use errors among children using booster seats (errors in use = 3.89 × DAB - 2.18, p < 0.0001)., Conclusion: The DAB score is a reliable and valid measure of comfort of children in child restraints but could be improved by incorporating a measurement of postural positioning. Comfort, as characterized by fidgeting and postural adjustment behaviors, is associated with correct use of child restraints. The broader implication is that this confirms ergonomic design of child restraints as important for minimizing errors in use. There is a need for further study of the impact of specific restraint design features on comfort experienced by children.

Objectives: We sought to identify the program fidelity factors associated with successful implementation of the Buckle-Up Safely program, targeting correct use of age-appropriate child car restraints., Methods: In 2010, we conducted a cluster randomized controlled trial of 830 families with children attending preschools and long day care centers in South West Sydney, New South Wales, Australia. Families received the Buckle-Up Safely program in the intervention arm of the study (13 services). Independent observers assessed the type of restraint and whether it was used correctly., Results: This detailed process evaluation showed that the multifaceted program was implemented with high fidelity. Program protocols were adhered to and messaging was consistently delivered. Results from multilevel and logistic regression analyses show that age-appropriate restraint use was associated with attendance at a parent information session hosted at the center (adjusted odd ratio [AOR]=3.66; 95% confidence interval [CI]=1.61, 8.29) and adversely affected by the child being aged 2 to 3 years (AOR=0.14; 95% CI=0.07, 0.30) or being from a family with more than 2 children (AOR=0.34; 95% CI=0.17, 0.67)., Conclusions: Findings highlight the importance of parents receiving hands-on education regarding the proper use of age-appropriate child restraints.

Objectives: To examine changes in child car restraint practices in low socioeconomic areas following the introduction of mandatory child car restraint legislation in New South Wales (NSW), Australia., Methods: Data from two cross-sectional studies of child car restraint use at pre-schools, early childhood centres and primary schools before and after the introduction of legislating mandatory age-appropriate car restraint use for children up to the age of seven years was used in this analysis. All included observations were from local government areas with socioeconomic status in the lowest 30% of urban Sydney. Children aged 2-5 years were observed in their vehicles as they arrived at observation sites (107 pre-legislation, 360 post-legislation). Multilevel logistic regression was used to examine changes in observed age-appropriate and correct use of car restraints., Results: Age-appropriate car restraint use was higher post-legislation than pre-legislation. After controlling for child's age, parental income, language spoken at home and adjusting for clustering, the odds of children being appropriately restrained post-legislation were 2.3 times higher than in the pre-legislation sample, and the odds of them being correctly restrained were 1.6 times greater., Conclusions: Results indicate an improvement in car restraint practices among children aged 2-5 in low socioeconomic areas after introduction of child restraint laws. Implications : Despite improvements observed with enhanced legislation, further efforts are required to increase optimal child car restraint use., (© 2013 The Authors. ANZJPH © 2013 Public Health Association of Australia.)

Objectives: To qualitatively explore barriers to optimal child restraint use using the integrative behaviour change model in culturally and linguistically diverse (CALD) communities in New South Wales (NSW), Australia., Methods: A semi-structured discussion was used to conduct 11 language specific focus groups in Arabic, Assyrian, Cantonese, Mandarin, Vietnamese and Turkish. Translated transcriptions were analysed using the major concepts of the integrative behaviour change model., Results: Restraint use intent among CALD community carers is related to perceived safety of their children and complying with the law. While most participants appreciated the safety benefits of correct and appropriate use, a minority did not. Child restraint legislation may positively influence social norms, and enforcement appears to increase parental self-efficacy. However, concerns over child comfort may negatively influence both norms and self-efficacy. There are clear deficits in knowledge that may act as barriers as well as confusion over best practice in safely transporting children. Large family size, vehicle size and cost appear to be real environmental constraints in CALD communities., Conclusion: Determinants of intent and deficits in knowledge in this diverse range of CALD communities in NSW Australia are similar to those reported in other qualitative studies regardless of the population studied. This indicates that key messages should be the same regardless of the target population. However, for CALD communities there is a specific need to ensure access to detailed information through appropriate delivery strategies and languages. Furthermore, practical constraints such as cost of restraints and family size may be particularly important in CALD communities.

Objectives: We evaluated an education, distribution, and fitting program for increasing age-appropriate and correct child restraint use., Methods: We performed a cluster randomized trial involving 28 early childhood education centers in low socioeconomic status areas in Sydney, Australia. The main outcome was optimal restraint use defined as age-appropriate restraints, installed into the vehicle correctly and used correctly., Results: One service withdrew after randomization, so data are presented for 689 child passengers, aged 3 to 5 years, from 27 centers. More children attending intervention centers were optimally restrained (43% vs 31%; P = .01; allowing for clustering). More 3-year-olds were using forward-facing seats rather than booster seats, more 4- to 5-year-olds were using booster seats instead of seat belts alone, and there were fewer errors in use at intervention centers. Among non-English-speaking families, more children attending intervention centers were optimally restrained (43% vs 17%; P = .002; allowing for clustering)., Conclusions: The program increased use of age-appropriate restraints and correct use of restraints, which translates to improved crash injury protection. Multifaceted education, seat distribution, and fitting enhanced legislation effects, and the effect size was larger in non-English-speaking families.

Little is known about child passenger safety practice in China. This study aims to describe child passenger seating and restraint practice in Shanghai. Information on 970 children enrolled in five randomly selected kindergartens in the Songjiang and Pudong districts of Shanghai was collected from a parental survey during 2008-2009. The adjusted rate ratios for optimal (rear-seated alone) versus suboptimal seating position (including front-seated or sitting in adult laps) and restraint use versus non-use of restraints among child passengers were evaluated using multivariate binomial regression. Suboptimal seating position (16.9%) and non-use of restraints (60.8%) was common among child passengers. Younger age (≤4 years) and having parents who are licensed drivers decreased the likelihood of being rear-seated alone; whereas having a tertiary-educated mother increased the likelihood of a child being seated optimally. Compared with unlicensed parents, guardian parents who have a driver's licence were more likely to use restraints for their child passengers. This study suggests restraint non-use and suboptimal seating position are common for child passengers in the Songjiang and Pudong districts of Shanghai, and identifies risk factors influencing restraint use and seating position choice for child passengers. There is an urgent need to improve child passenger safety in China and these findings indicate potential targets for educational interventions in the absence of child restraint laws.

This study evaluated the effectiveness of the NSW Restraint Fitting Station Network in preventing incorrect use of rearward facing and forward facing child restraints. The way children used restraints was observed randomly as they arrived at observation sites during a cross-sectional ecological study across New South Wales, Australia. Trained researchers examined restraint system installation once the child left the vehicle. A structured interview was also conducted with the driver. Logistic regression was used to examine the association between parental report of ever having the restraint checked at a Restraint Fitting Station and whether or not the restraint was used correctly, while controlling for potential confounders and accounting for the complex sample design. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. The results demonstrated that children of respondents who did not use Restraint Fitting Stations were 1.8 times more likely to be incorrectly using their restraints (95% CI 1.1-2.8) than children of Restraint Fitting Station users. Regardless of whether or not a Restraint Fitting Station had been used, there was a trend towards a greater likelihood of incorrect restraint use as the length of restraint ownership increased (OR 1.3 95% CI 1.0-1.7). These results are important for developing strategies aimed at reducing child occupant casualties by reducing the rate of incorrect restraint use, and support programs encouraging the use of Restraint Fitting Stations and similar services as a countermeasure to incorrect use., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Background: The benefits of correctly using size-appropriate restraints for children travelling in cars are well established, and considerable research has focused on the determinants of appropriate restraint choice. There are few studies of the factors associated with incorrect use. Objective To determine predictors of incorrect restraint use by child occupants and how these differ from inappropriate use., Methods: A stratified multistage cluster sample of child occupants aged 0-10 years in New South Wales, Australia was used. Observation of restraint type and inspection of correctness of use was performed on arrival at schools, childcare centres, and child health clinics. An interview was conducted with the driver. Logistic regression was performed to estimate the effects of parental, family, and other characteristics on the likelihood of moderate or serious incorrect restraint use for restraint classes (rear/forward facing, booster, and seatbelt)., Results: Significant factors varied depending on age and restraint class. Older child restraint users (OR per year of age 0.27, 95% CI 0.07 to 0.98) and seatbelt users (OR per year of age 0.54, 95% CI 0.45 to 0.64) were less likely to be incorrectly using their restraints than younger users. Child restraint and booster users from non-English speaking families were more likely to be incorrectly using their restraints. Having more children in the car appeared to reduce incorrect use for booster (OR 0.18, 95% CI 0.06 to 0.57) and seatbelt users (OR 0.39, 95% CI 0.16 to 0.93)., Conclusions: There is a need to reduce incorrect restraint use by both education and improved restraint design. Education aimed at reducing incorrect use may need to be targeted differently to appropriate use programmes, as the predictive factors differ.

Objective: This study aims to investigate the effects of seating posture and seat cushion properties on submarining risk for rear seated children., Methods: An instrumented 6-year-old Hybrid III dummy restrained by an inertial-reel 3-point seat belt was subjected to simulated frontal impacts (Δv=28.8 km/h, peak acceleration=16 g). Dummy motion was captured using high-speed digital video. Head acceleration, neck loads, chest deflection, pelvic rotation, and femur displacement were used to assess submarining. Factors investigated included pre-impact seating posture, seat cushion length, stiffness of the seat cushion foam, and the inclination of the seat cushion., Results: The most severe submarining was observed when the dummy was seated in a slouched posture where pelvic rotation was over 3 times greater than in the upright seating posture. Though the standard seat cushion with the dummy seated in the upright posture recorded the lowest values of pelvic rotation and femur displacement, it is unlikely that a child will sit in such a posture. The shortened seat cushion increased femur displacement by 19 percent compared to the standard test seat, but it offers good pre-impact belt position. Submarining occurred in cases where the front edge of the seat collapsed during interactions with the dummy's buttocks., Conclusions: These data suggest that shortening the rear seat cushion alone will not necessarily prevent submarining, but this does allow improved seated posture of the occupant, thus reducing submarining risk. This study has also shown that the collapse of the front edge of the seat cushion is a critical factor in submarining risk.

Background: Road traffic crashes for car occupants are a leading cause of death and serious injury in children from high and middle income countries globally. Correct use of appropriate child restraints can significantly reduce death and serious injury but there is a need for well powered trials to examine effectiveness of programs to increase optimal child restraint practices. The aim of this trial is to examine the effectiveness of a comprehensive intervention to increase the use of appropriate child restraints, and decrease incorrect use of child restraints in pre-school aged children traveling in cars., Methods and Design: A cluster randomised controlled trial will be conducted, involving 28 pre-school or childcare centres in low income areas of Sydney, Australia, over one calendar year. The intervention is an educational program involving an in-service for centre staff, distribution of educational materials to parents, a parent workshop demonstrating restraint use, subsidised restraints for parents in need, and vouchers for a free restraint checking service. Blinded assessors will observe restraint use at all centres at the end of the calendar year. Data will be analysed on an intention-to-treat basis; the primary analysis will compare the proportion of each of the two outcome measures (use of appropriate restraints, and incorrect use of restraints) at each centre between intervention and control groups. Detailed process evaluation will be conducted, including examination of implementation and utilisation of various elements of the program by both centres and families., Discussion: This assessor blinded cluster randomised trial is powered to provide credible evidence about the efficacy of an education and distribution program in a pre-school setting to increase appropriate use, and decrease incorrect use of child restraints., Trial Registration: Australian New Zealand Clinical Trials Registry ACTRN12609000612213.

This cross-sectional study provides population-referenced data on the restraints used and the extent of incorrect restraint use, among child vehicle passengers aged 0-12 years in NSW, Australia. A multistage stratified cluster sampling plan was used to randomly select vehicles from baby/child health clinics, pre-schools/day care centres, and primary schools across NSW to undergo detailed inspection of restraints used by child occupants within those vehicles. Overall, there were very high restraint usage rates (>99% of sampled children) but fewer than one quarter of children were using the correct size-appropriate restraints. Incorrect use (51.4%) was as common as inappropriate use (51.2%). Incorrect use was highest among users of dedicated child restraint systems (OR 16.0, 95% CI 6.9-36.0), and was more likely among those using size-appropriate restraints than those using inappropriate restraints (OR 1.8 95% CI 1.1-3.2); and among convertible restraints than those designed for a single mode of use (OR 1.5 95% CI 1.2-1.7). As incorrect use substantially reduces the protection from injury that is offered by child restraints, it is important that future strategies to reduce casualties among child occupants target both inappropriate and incorrect use., (2010 Elsevier Ltd. All rights reserved.)

Objective: We hypothesized that parents and caregivers would make better judgments about child restraint fit if shoulder height labeling was used to communicate appropriate child restraint transition times., Methods: Participants were recruited at a shopping center in New South Wales, Australia, and were observed choosing restraints, with and without shoulder height labels indicating appropriate restraint fit, for each of 2 test mannequins (representing a 3-year-old child and a 5-year-old child). Demographic and child restraint use experience data also were collected. Generalized estimating equations were used to examine associations between labeling condition and participant's judgment of restraint appropriateness., Results: Participants (N=86) made significantly fewer errors in judging restraint appropriateness for the test mannequins when the restraints included shoulder height labels (P<.001). Depending on label format, the odds that a participant would always make the correct decision were 5.2 (95% confidence interval: 2.7-9.8) to 3.7 (95% confidence interval: 2.0-6.9) times greater when shoulder height labels were included than when they were not., Conclusion: The use of shoulder height labels on child safety seats and booster seats is an effective means of communicating child restraint fit to parents and caregivers.

Objective: This study aims to provide population estimates of incorrect restraint use among children aged 0-12 traveling in cars in New South Wales (NSW) and describe the errors occurring in different restraint types., Methods: Observations of randomly selected children and restraints were conducted in situ by trained researchers at sites statewide. Observation sites were randomly selected using a multistage stratified sample plan. Restraint use errors were recorded and analyzed by severity of error and restraint type using complex survey analysis techniques., Results: One in two children was incorrectly restrained, and 38 percent in a serious manner. Multiple errors were common (31% of children). Both installation and "securing" errors were common, with installation errors more common in convertible restraints (rearward-facing/forward-facing restraints and forward-facing restraints/booster seats) than single-mode restraints (odds ratio [OR] 4.3; 95% confidence interval [CI] 1.7-10.8). Multiple errors were more common in convertible restraints (OR 3.6; 95% CI 1.9-7.0). The most frequently observed errors were excessive seat belt slack (>25 mm), incorrect belt routing, nonengagement of the seat belt buckle, very loose harness (>25 mm slack), harness off the shoulder, nonuse of belt guides, sash belt worn under the arm, and very twisted harnesses and belts (>2 twists). For rearward- and forward-facing restraints the highest priorities in terms of frequency and degradation in crash protection are errors related to harness use. For booster seat users the most important are those related to correct seat belt and belt guide use. For seat belt users, errors related to correct positioning of the sash belt are key., Conclusions: The results indicate that many errors are currently occurring in the way children are using restraints, as well as problems associated with the way child restraint systems are installed in vehicles. Incorrect use is particularly problematic in convertible restraints (rearward-facing/forward-facing restraints and forward-facing restraints/booster seats). Different priorities, in terms of the frequency and potential degradation in crash protection due to incorrect use for different restraint types, exist and these are important for those designing countermeasures to this problem.

Accessory child safety harnesses are available in some countries as alternative restraints for young children or as an accessory restraint used with booster seats. Their use, in Australia at least, is becoming more common. There have been concerns that the risk of misuse of these restraints outweighs any potential benefit this system might have over a retractable lap-shoulder belt system used with a booster seat. However to date there is no evidence to confirm or deny this. This study used laboratory simulated frontal crash tests to examine the performance of accessory child safety harness systems compared to the lap-shoulder belt when used alone and when used with two common designs of Australian booster seat. The performance of the child safety harness system when misused was also investigated. The results demonstrate that the correctly used child safety harness system performed no better than the lap-shoulder system, and in fact allows for a greater risk of submarining. Furthermore, one common form of child safety harness misuse, where the harness is over-tightened causing the lap belt to be positioned high over the abdomen, allowed extremely undesirable dummy motion. This involved gross submarining and direct contact between the harness system and the dummy's neck. These findings suggest that the risks associated with accessory child safety harness systems most likely outweigh any potential benefits, in frontal impacts at least.