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Compatibility of booster seats and vehicles in the US market
Traffic Injury Prevention
Abstract
Objective
Analyze booster and rear vehicle seat dimensions to identify the most frequent compatibility problems.
Methods
Measurements were collected from 40 high-back and backless boosters, and 95 left rear and center rear row seating positions in 50 modern vehicles. Dimensions were compared for 3800 booster/vehicle seat combinations. For validation and estimation of tolerance and correction factors, 72 booster installations were physically completed and compared with measurement-based compatibility predictions. Dimensions were also compared to the International Organization for Standardization (ISO) volumetric envelopes of forward-facing child restraints and boosters.
Results
Seat belt buckles in outboard positions accommodated the width of boosters better than center positions (success rates of 85.4% and 34.7%, respectively). Adequate head restraint clearance occurred in 71.9% to 77.2% of combinations, depending on the booster's head support setting. Booster recline angles aligned properly with vehicle seat cushion angles in 71.5% of combinations. In cases of poor angle alignment, booster angles were more obtuse than the vehicle seat angles 97.7% of the time. Head restraint interference exacerbated angle alignment issues. Data indicate success rates above 90% for boosters being fully supported by the length of the seat cushion and for adequate height clearance with the vehicle roofline. Comparison to ISO envelopes indicates that most boosters on the US market are taller and angled more obtusely than ISO target envelopes.
Conclusions
This study quantifies some of the common interferences between boosters and vehicles which may complicate booster usage. Data are useful for design and to prioritize specific problem areas.
... Based on this concern, the current study qualitatively compared the head excursions of ATDs seated in rearward-facing CRS models during rear impact sled tests to the roof heights of modern vehicles. The maximum ATD head excursions in plane of seatback did not exceed the roof heights for 98% of the vehicles previously measured by Bing et al. (2015Bing et al. ( , 2018. Thus, the risk of head contact against the vehicle roof appears to be low in most cases, which supports the lack of injuries from such a mechanism in the literature. ...
... Bing et al. (2015Bing et al. ( , 2018 previously reported roof height measurements from 128 seating positions across 87 different vehicles. Vehicles included in the analyses were a convenience sample of a variety of size classes from model years 2003-2015. ...
... Roof heights as measured in the plane of the seatback of a range of vehicle types summarized fromBing et al. (2018).Roof height in the plane of the seatback[mm] ...
Objective
The aim of the current study was to quantify the head excursions of pediatric anthropomorphic test devices (ATDs) seated in rearward-facing child restraint system (CRS) models during rear impact sled tests and compare to roof heights of vehicles in the current fleet to assess the possibility of head contact against the vehicle roof.
Methods
Head excursions of ATDs seated in rearward-facing CRS models were analyzed from high-speed video data from 14 rear impact sled tests across two different series. Tests were conducted in rigidized vehicle seats from recent model year vehicles. Rearward-facing infant and convertible CRS models were tested with a variety of pediatric ATDs aged 12 months to 6 years in a variety of installation conditions (e.g., lower anchors or seat belt, anti-rotation features, etc). Maximum ATD head excursions in plane of the seatback were compared to previously measured roof heights of 87 different vehicles.
Results
The roof heights in all sedan seating positions (n = 58) and SUV/CUV/minivan seating positions (n = 60) were greater than the largest maximum ATD head excursions in plane of the seatback (792 mm). Head contact was possible in two of the pickup trucks which had roof heights of 730 and 775 mm. In all, 98% of vehicle seating positions measured in this study would accommodate all of the maximum ATD head excursions in plane of the seatback without contact.
Conclusions
The risk of head contact against the vehicle interior roof appears low as maximum ATD head excursions in plane of the seatback were typically not great enough to reach the rooflines of the vehicles in the sample. Head contact appears possible in pickup trucks, where the window/roofline is directly behind the head restraint.
... The SUV seats used in this study have a length of 49.0 cm, which is longer than most seats on the current market [13,14]. To shorten the usable length of the seats, foam "spacers" were attached to the seat backs ( Figure 1). ...
... The final lengths of the vehicle seats with spacer modifications were 34.0 cm ("short" condition) and 43.5 cm ("long" condition). These lengths correspond to approximately the 2nd and 70th percentiles of vehicle seats on the current market [13,14]. ...
... CRS models with long base lengths were chosen so that the bases would overhang the front edge of the short vehicle seat conditions. Published literature was used as a guide for selecting CRS with long bases [13,14]. The Combi Shuttle (RF infant seat), Safety 1st Alpha Elite 65 (FF convertible mode), and Eddie Bauer Deluxe High Back 65 (high back booster mode) were selected. ...
div class="section abstract"> The objective is to determine whether responses and injury risks for pediatric occupants in child restraint systems (CRS) are affected by vehicle seat cushion stiffness and fore/aft cushion length. Eighteen sled tests were conducted using the Federal Motor Vehicles Safety Standard (FMVSS) 213 frontal pulse (48 km/h). Seats from a recent model year vehicle were customized by the manufacturer with three different levels of cushion stiffness: compliant, mid-range, and stiff. Each stiffness level was quantified using ASTM D 3574-08 and all were within the realistic range of modern production seats. The usable length of each seat cushion was manipulated using foam spacers provided by the manufacturer. Two different seat lengths were examined: short (34.0 cm) and long (43.5 cm). Three different types of CRS were tested with size-appropriate anthropomorphic test devices (ATDs): rear-facing (RF) CRS with 12-month-old CRABI, forward-facing (FF) CRS with Hybrid III 3-year-old, and high-back booster with Hybrid III 6-year-old. Each CRS, vehicle seat (including cushion and frame), seat belt webbing and buckle were replaced after every test. ATD kinematic and kinetic data were compared across seat cushion lengths and cushion stiffness levels to determine which seat configurations were the most beneficial for each type of CRS. For RF CRS, short vehicle seats allowed more y-axis rotation (SAE J211) but reduced several injury metrics including HIC36. For FF CRS, long and short seats resulted in similar injury metrics across matched conditions. For boosters, short seats increased chest resultant acceleration but did not have a noticeable effect on other injury metrics. The range of cushion stiffness examined in this study did not have a consistent or relevant effect on any of the CRS or occupant responses.
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... The results showed that the seat belts absorb the impact energy, so the webbing stiffness directly affects the injury response of the dummy. Bing et al. [13] analyzed the correlation between the seat cushion angle and injury indices, and between the backrest stiffness and injury indices. The results showed that the seat cushion angle can influence a child's sitting posture before the car crash and kinematic posture in the car crash, while the backrest stiffness affects the deformation of the seat, thereby affecting the response of injury indices. ...
... Sci. 2023, 13, 2206 ...
To improve the safety of middle-aged and older child occupants, this paper proposes a framework to effectively design the layout parameters of child booster seats. The layout parameters of the child booster seat include both the three-point seat belt restraint path parameters and the structural design parameters. First, based on a validated frontal collision simulation model with the sled test, a parametric study of child booster seats for different injury indices is performed based on ECE R129 regulations in terms of a Q6 child dummy. To evaluate the effects of each parameter on the overall injury for children, the modified Weighted Injury Criterion (WIC) is proposed. Then, a parameter sensitivity based on the modified WIC is conducted to screen out parameters that have a significant impact on the response of injury indices. The position of the shoulder belt guide and the stiffness of the backrest have dominant effects on the WIC. Finally, a full factorial experiment is conducted for the above selected design variables based on the newly proposed WIC. The identified design position of the shoulder belt guide is 48 mm and its value corresponds to 30 mm of the relevant headrest position, which is explicitly utilized in the design process. The identified stiffness of the backrest is 30,400 Nm/rad. The corresponding WIC is decreased significantly, and the value is reduced by 19.6% compared with the reference model.
... The configuration measures between 15 to 19 in. in most modern vehicles, with some up to 23 in. or wider (Aram and Rockwell 2012;Bing et al. 2018;Klinich et al. 2014a). ...
... The lower anchors protruded through the seat bight and were accessible to users in the rear row ( Figure 2). Lower anchor spacing increments were set at 11, 15, 19, and 23 in., based on data from the modern vehicle fleet (Aram and Rockwell 2012;Bing et al. 2018;Klinich et al. 2014a convertible) were used in the study. These CRSs include a belt path for a single lower connector strap and have bases that comfortably fit between standard 11-in. ...
Objectives: The objective of this study was to determine whether the amount of tension required for proper child restraint system (CRS) installation varies with lower anchor spacing and to determine whether nonexperts can produce adequate tension on wider-than-standard lower anchor configurations.
Methods: CRSs were installed by certified child passenger safety technicians (CPSTs; n = 6 subjects, n = 72 installations) and nonexperts (n = 30 subjects, n = 120 installations) on a mock-up vehicle seat fixture with lower anchors set at 11 (standard), 15, 19, and 23 in. apart from one another. Each CPST installed a rear-facing (RF) infant base, RF convertible, and forward-facing (FF) convertible into each of the 4 spacing configurations in random order. The CPSTs were instructed to tighten the lower connector strap until the tension was exactly at the threshold between passing and failing the 1-in. test. Each nonexpert installed one CRS model into all 4 spacing conditions in random order. Nonexperts were instructed to install the CRS to the best of their ability. The tension produced on the lower connector strap was recorded via load cell in the lower anchor assembly of the vehicle seat. Resultant tension magnitudes were compared across spacing conditions using matched pair t-tests. The CPSTs’ mean 1-in. test threshold values were compared to tensions produced by nonexperts. Installations were visually evaluated for errors and qualitative usability feedback was collected via survey.
Results: CPSTs installed the infant base with higher tensions in the 15-, 19-, and 23-in. configurations compared to the standard 11-in. configuration (P = .034, .032, and .003, respectively). The nonexperts installed the infant base with higher tension in the 15- and 23-in. configurations compared to the 11-in. configuration (P = .004 and .026, respectively). The RF convertible and FF convertible installations showed no significant differences in tension among any of the spacing configurations for either group. Only 19% of the nonexperts’ installations were tight enough to pass CPST thresholds, and the pass rate did not vary with respect to lower anchor spacing. In feedback surveys, the nonexpert group did not show a consistent preference for either standard or wider-than-standard lower anchor configurations.
Conclusions: The amount of tension required to pass the 1-in. rule did not vary with lower anchor spacing configurations for the RF and FF convertible CRS, but the infant base required more tension in wider anchor configurations. Nonexperts tended to produce less than ideal tension in all configurations, although their tension magnitudes increased for the infant base in wider configurations.
... This interaction can create a gap between the back surface of the CRS and the vehicle seat (i.e., "HR interference"). Previous compatibility studies estimate that HR interference occurs in roughly 33% to 50% of FF CRS installations and 28% of high-back booster installations (Hu et al. 2015, Bing et al. 2015, Bing et al. 2018. HR interference can cause the CRS to sit pitched at unintended angles during normal travel and reduce the area of contact between the back surface of the CRS and the vehicle seat back. ...
div class="section abstract"> Forward-facing child restraint systems (FF CRS) and high-back boosters often contact the vehicle seat head restraint (HR) when installed, creating a gap between the back surface of the CRS and the vehicle seat. The effects of HR interference on dynamic CRS performance are not well documented. The objective of this study is to quantify the effects of HR interference for FF CRS and high-back boosters in frontal and far-side impacts. Production vehicle seats with prominent, removeable HRs were attached to a sled buck. One FF CRS and two booster models were tested with the HR in place (causing interference) and with the HR removed (no interference). A variety of installation methods were examined for the FF CRS. A total of twenty-four tests were run. In frontal impacts, HR interference produced small but consistent increases in frontal head excursion and HIC36. Head excursions were more directly related to the more forward initial position rather than kinematic differences caused by HR interference. In far-side impacts, HR interference did not have consistent effects on injury metrics. Overall, these results suggest only slight benefits of removing the HR in frontal impacts specifically. Caregivers should use caution if removing a vehicle HR to ensure that the current child occupant and all future vehicle occupants have adequate head support available in case of a rear impact.
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... For example, the inboard edge of the shoulder belt was positioned more inboard than the suprasternale (SSN) at the level of the SSN on the Q6 ATD, resulting in negative SBS. The placement of the shoulder belt could also be attributed to the difference in vehicle seat geometry which could affect the position of the shoulder belt outlet (Bing et al., 2018), and hence, the SBS. Despite these anthropometric variations, the difference in SBS between the boosters was similar for the Q6 ATD evaluated in this study and the child volunteer data reported previously. ...
Research questions / objective: Test protocols evaluate restraint performance with pediatric ATDs placed in an ideal seating posture. However, real-world evidence suggests that ideal test conditions do not always reflect actual occupant positions. Prior studies have also shown that booster seat designs affect the position of the seatbelt around the child. Occupants in naturalistic seating postures, coupled with potentially unfavorable seatbelt positions, could result in adverse kinematics and kinetics in a crash. Therefore, the aim of this study was to quantify the effect of different naturalistic seating postures on the response of the Q6 ATD restrained on boosters with varying initial static belt fit in a frontal impact.
Methods/data sources: The Q6 ATD was positioned on two booster seats of similar design but varying static belt fit metrics in three seating postures: reference, leaning forward, and leaning inboard. These booster seats were chosen from extensive belt fit studies on human volunteers and ATDs, and were defined as follows:
• Booster A: more inboard shoulder belt position, more inferior lap belt position, larger gap size.
• Booster B: more outboard shoulder belt position, more superior lap belt position, smaller gap size.
The booster-seated ATD was restrained on the simulated Consumer Reports test buck (2010 Ford Flex 2nd row seat) with a front blocker plate using a 3-point lap-shoulder belt with a retractor and pre-tensioner. The sled environment was subjected to the FMVSS 213 frontal impact pulse, and each booster and seating posture was evaluated twice (n = 12 sled tests). Kinematic and kinetic measures were recorded. A linear regression analysis was conducted across postures on each booster. Further, a paired t-test analysis was conducted across booster seats for each seating posture.
Results: Across seating postures, the reference posture exhibited similar or higher kinematic and kinetic metric values compared to the leaning forward and leaning inboard postures on both boosters. However, both leaning forward (Booster A = 279.5 ± 21.6 mm; Booster B = 298.8 ± 1.5 mm) and leaning inboard (Booster A = 308.7 ± 1.1 mm; Booster B = 331.4 ± 8.5 mm) postures generally resulted in greater head excursion than the reference posture (Booster A = 285.0 ± 16.9 mm; Booster B = 288.1 ± 1.5 mm), indicating greater potential for head contact.
Between boosters, Booster A resulted in significantly lower head 3 ms clip acceleration (p = 0.0026), HIC15 (p = 0.0008), upper neck tensile force (F z)(p = 0.0057), chest 3 ms clip acceleration (p = 0.0013), and right abdominal pressure (p = 0.0163), and significantly higher left ASIS force (F x)(p = 0.0150) and left (p = 0.0489) and right (p = 0.0088) ASIS moment (M y) than Booster B. Upper neck tensile forces on Booster B crossed the 20% and 50% thresholds for AIS3 + injury. Lower abdominal pressure and higher ASIS forces and moments on Booster A suggest that the lap belt loaded the ASIS appropriately, and hence, relatively better kinematics than Booster B.
Significance of results: This study shows that booster design affects static belt fit which can have an effect on dynamic crash performance and assessment criteria. By connecting static belt fit to dynamic performance, these effects may have the potential to help guide booster seat design.
... The bottom vehicle seat cushion was modified to allow for three lower anchor locations: baseline, forward, and wide (Table AII, Fig. A1). The seatbelt anchor locations represented the middle and maximum of the range of allowable angles defined by FMVSS 210 [20] and the minimum and maximum anchor widths measured previously for 50, model year 2008-2015 vehicles [21] [22]. The seatbelt outlet location was held constant for all trials (Fig. A2). ...
Shoulder and lap belt scores have been previously quantified for anthropomorphic test devices on belt-positioning booster seats; however, they may not fully discriminate between good vs. poor dynamic outcomes. To determine the influence of initial belt fit and gap on dynamic outcomes, the ability of anthropomorphic test devices to represent realistic child belt fit and gap on belt-positioning booster seats must first be understood. This study compares posture, belt fit, and belt torso contact between the Hybrid III (HIII) 6-year-old, HIII 10-year-old, HIII 5 th percentile Female, and the Large Omni Directional Child 10-year-old anthropomorphic test devices to a cohort of 50 children on ten belt-positioning booster seats and three seatbelt anchor locations. Novel belt fit metrics (e.g., gap size, gap length, and belt torso contact) and conventional shoulder and lap belt scores were quantified using a 3D coordinate measurement system. Overall, the anthropomorphic test devices had more inboard shoulder belt position, overestimated gap size and length, and underestimated belt torso contact compared to children; however, anthropomorphic test device posture, belt fit, and belt gap outcomes were moderately or strongly associated with child outcomes, suggesting that they can be used to represent realistic variation in initial belt fit and gap conditions.
To increase booster seat use among low income parents. Design/methods: A pre-test/post-test design conducted in nine daycare centers with post-test observations four to eight weeks after the intervention.
Parents who participated in an educational training received free seats, educational programs were provided to all daycare staff and children, and signs in parking lots informed parents about child restraints. At seven centers, new policies recommended compliance with state restraint laws. Parents at four centers randomly chosen from the seven received financial incentives if observed using booster seats.
The percent of children aged 4-8 riding in booster seats.
Pre-test observations of 185 4-8 year olds found 56% riding unrestrained and fewer than 3% riding in booster seats. After the intervention, observation of 146 children found the number riding in booster seats increased to 38% and the number observed without restraints decreased to 26%. Most booster seat use occurred with 4 and 5 year olds. No 7 or 8 year olds rode in booster seats. Changing center policies to recommend compliance with state restraint laws and an offer of financial incentives appeared to have no additional impact.
Booster seat usage among low income families can be increased dramatically, though use decreases with age. Providing free seats accompanied by training may be sufficient without the need for additional intervention.
Objective:
Child restraint system (CRS) misuse is common and can have serious consequences to child safety. Physical incompatibilities between CRS and vehicles can complicate the installation process and may worsen CRS misuse rates. This study aims to identify the most common sources of incompatibility between representative groups of CRS and vehicles.
Methods:
Detailed dimensional data were collected from 59 currently marketed CRS and 61 late model vehicles. Key dimensions were compared across all 3,599 theoretical CRS/vehicle combinations and the most common predicted incompatibilities were determined. A subset of 34 physical installations was analyzed to validate the results.
Results:
Only 58.2% of rear-facing (RF) CRS/vehicle combinations were predicted to have proper agreement between the vehicle's seat pan angle and the CRS manufacturers' required base angle. The width of the base of the CRS was predicted to fit snugly between the vehicle's seat pan bolsters in 63.3% of RF CRS/vehicle combinations and 62.2% of forward-facing (FF) CRS/vehicle combinations. FF CRS were predicted to be free of interaction with the vehicle's head restraint in 66.4% of combinations. Roughly 90.0% of RF CRS/vehicle combinations were predicted to have enough horizontal clearance space to set the front seat in the middle its fore/aft slider track. Compatibility rates were above 98% regarding the length of the CRS base compared to the length of the vehicle seat pan and the ability of the top tether to reach the tether anchor. Validation studies revealed that the predictions of RF CRS base angle range vs. seat pan angle compatibility were accurate within 6%, and head restraint interference and front row clearance incompatibilities may be more common than the dimensional analysis approach has predicted.
Conclusions:
The results of this study indicate that RF CRS base angles and front row clearance space, as well as FF CRS head restraint interference, are frequent compatibility concerns. These results enable manufacturers, researchers, and consumers to focus their attention on the most relevant CRS/vehicle incompatibility issues in today's market.
Objectives:
The objectives of this study are to use computer simulation to evaluate the International Organization for Standardization (ISO) 13216-3:2006(E) child restraint system (CRS) envelopes relative to rear seat compartments from vehicles and CRSs in the U.S. market, investigate the potential compatibility issues of U.S. vehicles and CRSs, and demonstrate whether necessary modifications can be made to introduce such a system into compatibility evaluations between U.S. vehicles and CRSs.
Methods:
Three-dimensional geometry models for 26 vehicles and 16 convertible CRS designs developed previously were used. Geometry models of 3 forward-facing and 3 rear-facing CRS envelopes provided by the ISO were built in the current study. The virtual fit process closely followed the physical procedures described in the ISO standards.
Results:
The results showed that the current ISO rear-facing envelopes can provide reasonable classifications for CRSs and vehicles, but the forward-facing envelopes do not represent products currently in the U.S. market. In particular, all of the selected vehicles could accommodate the largest forward-facing CRS envelope at the second-row seat location behind the driver seat. In contrast, half of the selected CRSs could not fit within any of the forward-facing ISO CRS envelopes, mainly due to protrusion at the rear-top corner of the envelope. The results also indicate that the rear seat compartment in U.S. vehicles often cannot accommodate a large portion of convertible CRSs in the rear-facing position. The increased demand for vehicle fuel economy and the recommendation to keep children rear-facing longer may lead to smaller cars and larger CRSs, which may increase the potential for fit problems.
Conclusions:
The virtual classifications indicated that contact between the forward-facing CRSs and the head restraints in the rear seats as well as that between the rear-facing CRSs and the back of the front seats is a main concern regarding the compatibility between the vehicles and the CRSs. Therefore, modification of the current ISO forward-facing CRS envelopes will likely to be necessary to ensure that they are useful for the U.S. market.
The objective of this study was to provide an updated estimate of the effectiveness of belt-positioning booster (BPB) seats compared with seat belts alone in reducing the risk for injury for children aged 4 to 8 years.
Data were collected from a longitudinal study of children who were involved in crashes in 16 states and the District of Columbia from December 1, 1998, to November 30, 2007, with data collected via insurance claims records and a validated telephone survey. The study sample included children who were aged 4 to 8 years, seated in the rear rows of the vehicle, and restrained by either a seat belt or a BPB seat. Multivariable logistic regression was used to determine the odds of injury for those in BPB seats versus those in seat belts. Effects of crash direction and booster seat type were also explored.
Complete interview data were obtained on 7151 children in 6591 crashes representing an estimated 120646 children in 116503 crashes in the study population. The adjusted relative risk for injury to children in BPB seats compared with those in seat belts was 0.55.
This study reconfirms previous reports that BPB seats reduce the risk for injury in children aged 4 through 8 years. On the basis of these analyses, parents, pediatricians, and health educators should continue to recommend as best practice the use of BPB seats once a child outgrows a harness-based child restraint until he or she is at least 8 years of age.
A case-control study examined, primarily, the association between booster seat laws and fatalities among children in frontal collisions and, secondarily, the association between booster seat laws and reported restraint use, and restraint use and child fatalities. Children who died in a crash in the US were cases, and children who survived a fatal crash were controls. Subjects were child passengers (4-8 years old) in the Fatality Analysis Reporting System Database, 1995-2005. In states with a booster seat law, children were less likely to die than in states without a law (OR 0.80; 95% CI 0.66 to 0.98). They were also more likely to be restrained (adjusted OR 1.59; 95% CI 1.21 to 2.09) and were more likely to be correctly restrained (adjusted OR 4.44; 95% CI 3.18 to 6.20). It is concluded that booster seat laws are associated with a decrease in child deaths and an increase in correct restraint use among children involved in a fatal crash in the USA.
Observe and report seat belt use among children transported in belt-positioning booster seats.
We conducted a cross-sectional, observational survey of children transported in motor vehicles between 2006 and 2007. While drivers completed a survey reporting the child's age, weight and gender, and the driver's age, gender, race, income, education, and relationship to the child; a child passenger safety technician recorded vehicle seating location, restraint type, and use of the car safety seat harness or seat belt as appropriate for the child.
Twenty-five fast food restaurants and discount department stores throughout Indiana.
A convenience sample of drivers transporting children younger than 16 years.
Seat belt use among children transported in belt-positioning booster seats.
Seat belt misuse.
Overall, 1446 drivers participated, 2287 children were observed with 564 children in belt-positioning booster seats. At least one seat belt misuse was observed for 64.8% of the children transported. Common misuses were the shoulder belt being placed over the booster seat armrest (35.8%); shoulder belt not at mid-shoulder position (28.5%), seat belt was too loose (24.5%), and the shoulder belt was either behind the child's back (9.1%) or under their arm (10.0%).
There is a high frequency of seat belt misuses among children transported in booster seats. Advice to parents on appropriate car seat selection, and encouragement to parents to supervise seat belt use may decrease misuse.
Many children 4 to 9 years old are inappropriately restrained in vehicles and are at risk for injury in crashes.
This study was undertaken to determine the rate of booster seat use and the reasons for nonuse.
Observations were conducted at a random sample of day care centers, and drivers of unrestrained children 4 to 8 years old were interviewed to determine the reasons for lack of booster seat use.
Observations were conducted on 149 children. Shoulder belt use significantly increased with the age of the child; 28.3% of 4-year-olds and 70.0% of 6- to 8-year-olds used lap-shoulder belts. Overall, 27.7% of children in the target age group used booster seats; only 10% of children 6 to 8 years old were restrained with booster seats. Booster seat use decreased when there were 3 or more passengers in the vehicle. The most common reason for lack of booster seat use was that parents thought the child was large enough to use the regular lap-shoulder belt system, or problems with attempting to use the seat in the vehicle. More than one half of parents who were not using booster seats at the time of the survey reported owning seats.
This study indicates that parental misconceptions about size and safety of regular restraint equipment are the most common reason that children are not appropriately restrained in vehicles. This information can be used to guide community intervention programs.
Children who have outgrown child safety seats and been placed in adult seat belts are at increased risk for injury. Pediatricians and other advocates have been called on to encourage booster seat use in these children. The objective of this study was to identify barriers to booster seat use and strategies to increase their use.
A qualitative study consisting of focus groups and follow-up in-depth discussions were conducted among parents and/or children to elicit barriers and strategies to appropriate/best practice child restraint system use. Phase I focus groups (parents and children) identified barriers to booster seat use along with children's self-reported likes and dislikes about booster seats. Phase II focus groups (parents only) identified additional barriers to booster seat use and suggestions for strategies to increase the use of booster seats. In-depth telephone discussions (parents only) were conducted after each phase of focus groups to identify new themes and to explore further previously emerged topics that were not conducive to probing in focus group settings.
This study demonstrated that although knowledge of the benefits and purpose of booster seats is an important issue in promoting booster seat use, it is not the only issue. In particular, differences in risk perception, awareness/knowledge, and parenting style were noted when comparing parents of children in booster seats with those whose children were in seat belts. Media campaigns, improved laws, parenting education, and extending the use of child restraints to older ages were among the strategies suggested by parents to increase booster seat use.
Anticipatory guidance regarding booster seats may be new for many pediatricians. This article arms pediatricians with insights from parents about their perceptions regarding booster seats and how parents think that the booster seat message can be most effectively delivered. Furthermore, it gives insight into how parents make safety decisions for their children and the important role of children in this decision-making process.
To identify parent driver demographic and socioeconomic characteristics associated with the use of sub-optimal restraints for child passengers under nine years.
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.
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 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.
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.
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.
The 2015 National Survey of the Use of Booster Seats
- H R Li
- T M Pickrell
- K C Shova
Instrumentation for Impact Test-Part 1-Electonic Instrumentation J211/1. Warrendale, PA: Author
- Sae International