A data-driven allocation tool for in-kind resources distributed by a state health department

Objective: The objective of this study was to leverage a state health department's operational data to allocate in-kind resources (children's car seats) to counties, with the proposition that need-based allocation could ultimately improve public health outcomes.

Methods: This study used a retrospective analysis of administrative data on car seats distributed to counties statewide by the Georgia Department of Public Health and development of a need-based allocation tool (presented as interactive supplemental digital content, adaptable to other types of in-kind public health resources) that relies on current county-level injury and sociodemographic data.

Results: Car seat allocation using public health data and a need-based formula resulted in substantially different recommended allocations to individual counties compared to historic distribution.

Conclusions: Results indicate that making an in-kind public health resource like car seats universally available results in a less equitable distribution of that resource compared to deliberate allocation according to public health need. Public health agencies can use local data to allocate in-kind resources consistent with health objectives; that is, in a manner offering the greatest potential health impact. Future analysis can determine whether the change to a more equitable allocation of resources is also more efficient, resulting in measurably improved public health outcomes.     

Standardized error severity score (ESS) ratings to quantify risk associated with child restraint system (CRS) and booster seat misuse

Objective: Although numerous research studies have reported high levels of error and misuse of child restraint systems (CRS) and booster seats in experimental and real-world scenarios, conclusions are limited because they provide little information regarding which installation issues pose the highest risk and thus should be targeted for change. Beneficial to legislating bodies and researchers alike would be a standardized, globally relevant assessment of the potential injury risk associated with more common forms of CRS and booster seat misuse, which could be applied with observed error frequency—for example, in car seat clinics or during prototype user testing—to better identify and characterize the installation issues of greatest risk to safety.

Methods: A group of 8 leading world experts in CRS and injury biomechanics, who were members of an international child safety project, estimated the potential injury severity associated with common forms of CRS and booster seat misuse. These injury risk error severity score (ESS) ratings were compiled and compared to scores from previous research that had used a similar procedure but with fewer respondents. To illustrate their application, and as part of a larger study examining CRS and booster seat labeling requirements, the new standardized ESS ratings were applied to objective installation performance data from 26 adult participants who installed a convertible (rear- vs. forward-facing) CRS and booster seat in a vehicle, and a child test dummy in the CRS and booster seat, using labels that only just met minimal regulatory requirements. The outcome measure, the risk priority number (RPN), represented the composite scores of injury risk and observed installation error frequency.

Results: Variability within the sample of ESS ratings in the present study was smaller than that generated in previous studies, indicating better agreement among experts on what constituted injury risk. Application of the new standardized ESS ratings to installation performance data revealed several areas of misuse of the CRS/booster seat associated with high potential injury risk.

Conclusions: Collectively, findings indicate that standardized ESS ratings are useful for estimating injury risk potential associated with real-world CRS and booster seat installation errors.     

Parental awareness and perception for correct use of child restraint systems and airbags in Brazil

Objective: The objective of this study was to obtain information about the current knowledge and habits of parents who transport children in cars in Brazil.

Methods: A cross-sectional survey was conducted using specifically designed self-report questionnaires to parents of children attending a private pediatric office in a town in southwest Brazil. Data were collected regarding children's age, gender, height, and weight and possession of an automobile child restraint system (CRS), its type, frequency and adequacy of use, and reasons for not possessing or not using the devices. Parents were asked whether their cars were equipped with airbags and about the use of the restraints in seats with airbags.

Results: We interviewed parents of 293 children transported in cars who met the criteria for use of a CRS. Children were younger than 1 year in 15.3% of the cases, between 1 and 4 years in 38.6%, and older than 4 in 46.1%. Cars were equipped with CRS in 78.5% of the cases, but in only 58% of the cases was the device proper for child's age and adequately installed in the seat. Among owners of the devices, 84.3% reported that they always used it. Reasons for infrequency were forgetting the device at home or in another car (6.4%), the child disliking the device (3.2%), or the false impression that the child was grown enough not to use it (3.2%)l 87.1% did not justify why they did not always use the CRS. Considering type of CRS, correct installation of the seat, and frequency of use, only 44.4% of children under 1 year, 69.9% of those 1 to 4 years, and 52.6% over age 4 were protected. Only 28.6% of the parents knew that children should never be positioned in a seat with active airbags.

Conclusion: Considering appropriateness for age, correctness of installation (in the back seat in the correct orientation), and frequency of use, only 50.85% (149/293) of the children were reported as always protected with a CRS. Children between 1 and 4 years were more likely to always use a CRS in this Brazilian survey. We were also able to identify an important gap in the knowledge about airbags among parents. Further efforts are needed to correct those distortions.     

Seat strength in rear body block tests

Purpose: This study collected and analyzed available testing of motor vehicle seat strength in rearward loading by a body block simulating the torso of an occupant. The data were grouped by single recliner, dual recliner, and all belts to seat (ABTS) seats.

Methods: The strength of seats to rearward loading has been evaluated with body block testing from 1964 to 2008. The database of available tests includes 217 single recliner, 65 dual recliner, and 18 ABTS seats. The trends in seat strength were determined by linear regression and differences between seat types were evaluated by Student's t-test. The average peak moment and force supported by the seat was determined by decade of vehicle model year (MY).

Results: Single recliner seats were used in motor vehicles in the 1960s to 1970s. The average strength was 918 ± 224 Nm (n = 26) in the 1960s and 1,069 ± 293 Nm (n = 65) in the 1980s. There has been a gradual increase in strength over time. Dual recliner seats started to phase into vehicles in the late 1980s. By the 2000s, the average strength of single recliner seats increased to 1,501 ± 335 Nm (n = 14) and dual recliner seats to 2,302 ± 699 Nm (n = 26). Dual recliner seats are significantly stronger than single recliner seats for each decade of comparison (P < .001). The average strength of ABTS seats was 4,395 ± 1,185 in-lb for 1989–2004 MY seats (n = 18). ABTS seats are significantly stronger than single or dual recliner seats (P < .001). The trend in ABTS strength is decreasing with time and converging toward that of dual recliner seats.

Conclusions: Body block testing is an quantitative means of evaluating the strength of seats for occupant loading in rear impacts. There has been an increase in conventional seat strength over the past 50 years. By the 2000s, most seats are 1,700–3,400 Nm moment strength. However, the safety of a seat is more complex than its strength and depends on many other factors.     

An observational study of child safety seat use in an international safe community: Tehran,Iran

Objective: Despite strong evidence of the effectiveness of child safety seats in reducing injuries, the use of these devices in some communities is still rare. The purpose of this study was to determine the prevalence of child safety seat use and the factors influencing its use in the safe community of Tehran.

Methods: This roadside observational study was conducted in 2015 and 2,178 personal cars with a child under 12 years aboard were observed on Tehran's streets in regard to use of child safety seats. Other variables such as the gender of the driver, driver's age group, type of street, region of municipality, time of day, and day of the week were also collected.

Results: Prevalence of child safety seat use was 4.3% and was significantly higher among women drivers, on freeways, and in municipal regions 1, 4, and 7.

Conclusions: The prevalence of child safety seat use in Tehran as a most populous member of the international safe community was very low and most children commuted in insecure situations in the vehicle. Therefore, it is proposed that plans should be made to increase the use of child safety seats in international safe communities.     

Occupant responses in conventional and ABTS seats in high-speed rear sled tests

Objective: This study compared biomechanical responses of a normally seated Hybrid III dummy on conventional and all belts to seat (ABTS) seats in 40.2 km/h (25 mph) rear sled tests. It determined the difference in performance with modern (≥2000 MY) seats compared to older (<2000 MY) seats and ABTS seats.

Methods: The seats were fixed in a sled buck subjected to a 40.2 km/h (25 mph) rear sled test. The pulse was a 15 g double-peak acceleration with 150 ms duration. The 50th percentile Hybrid III was lap–shoulder belted in the FMVSS 208 design position. The testing included 11 <2000 MY, 8 ≥2000 MY, and 7 ABTS seats. The dummy was fully instrumented, including head accelerations, upper and lower neck 6-axis load cells, chest acceleration, thoracic and lumbar spine load cells, and pelvis accelerations. The peak responses were normalized by injury assessment reference values (IARVs) to assess injury risks. Statistical analysis was conducted using Student's t test. High-speed video documented occupant kinematics.

Results: Biomechanical responses were lower with modern (≥2000 MY) seats than older (<2000 MY) designs. The lower neck extension moment was 32.5 ± 9.7% of IARV in modern seats compared to 62.8 ± 31.6% in older seats (P =.01). Overall, there was a 34% reduction in the comparable biomechanical responses with modern seats. Biomechanical responses were lower with modern seats than ABTS seats. The lower neck extension moment was 41.4 ± 7.8% with all MY ABTS seats compared to 32.5 ± 9.7% in modern seats (P =.07). Overall, the ABTS seats had 13% higher biomechanical responses than the modern seats.

Conclusions: Modern (≥2000 MY) design seats have lower biomechanical responses in 40.2 km/h rear sled tests than older (<2000 MY) designs and ABTS designs. The improved performance is consistent with an increase in seat strength combined with improved occupant kinematics through pocketing of the occupant into the seatback, higher and more forward head restraint, and other design changes. The methods and data presented here provide a basis for standardized testing of seats. However, a complete understanding of seat safety requires consideration of out-of-position (OOP) occupants in high-speed impacts and consideration of the much more common, low-speed rear impacts.     

IIHS head restraint ratings and insurance injury claim rates

Objectives: The Insurance Institute for Highway Safety (IIHS) rates front seat/head restraint designs using a combination of static and dynamic measurements following RCAR-IIWPG procedures. The purpose of this study was to determine whether vehicles with better IIHS-rated seats/head restraints had lower injury risk in rear-end collisions and how the effect of better rated seats interacted with driver gender and age.

Methods: The presence of an associated insurance injury claim was determined for rear-impact crashes using 2001–2014 model year cars and SUVs. Logistic regression was used to compare injury risk for vehicles with good, acceptable, and marginal IIHS-rated seats/head restraints with poor-rated seats/head restraints. Analyses were run by gender and driver age and also by the rate of more severe injury claims.

Results: Injury rates were 11.2% lower for vehicles with seats/head restraints rated good compared to vehicles with seats/head restraints rated poor. The percentage reduction for good- versus poor-rated seats was greater for females (12.7%) than males (8.9%). Comparing good- with poor-rated seats, driver ages 15–24 had the largest reduction at 19.8%, followed by 10.7% for driver ages 45–64 and 10.4% for driver ages 25–44.

Conclusions: Seats/head restraints with better IIHS ratings are associated with lower injury rates in rear-impact collisions than seats rated poor. The reductions in injury rates were strongest for females and for young-to–middle-age drivers. The strong reductions in injury rates for these groups are encouraging given their high initial injury rates.     

Differences in the kinematics of booster-seated pediatric occupants using two different car seats

Objective: The objective of this article is to compare the performance of forward-facing child restraint systems (CRS) mounted on 2 different seats.

Methods: Two different anthropomorphic test device (ATD) sizes (P3 and P6), using the same child restraint system (a non-ISOFIX high-back booster seat), were exposed to the ECE R44 regulatory deceleration pulse in a deceleration sled. Two different seats (seat A, seat B) were used. Three repetitions per ATD and mounting seat were done, resulting in a total of 12 sled crashes. Dummy sensors measured the head tri-axial acceleration and angular rate and the thorax tri-axial acceleration, all acquired at 10,000 Hz. A high-speed video camera recorded the impact at 1,000 frames per second. The 3D kinematics of the head and torso of the ATDs were captured using a high-speed motion capture system (1,000 Hz). A pair-matched statistical analysis compared the outcomes of the tests using the 2 different seats.

Results: Statistically significant differences in the kinematic response of the ATDs associated with the type of seat were observed. The maximum 3 ms peak of the resultant head acceleration was higher on seat A for the P3 dummy (54.5 ± 1.9 g vs. 44.2 ± 0.5 g; P =.012) and for the P6 dummy (56.0 ± 0.8 g vs. 51.7 ± 1.2 g; P =.015). The peak belt force was higher on seat A than on seat B for the P3 dummy (5,488.0 ± 198.0 N vs. 4,160.6 ± 63.6 N; P =.008) and for the P6 dummy (7,014.0 ± 271.0 N vs. 5,719.3 ± 37.4 N; P =.015). The trajectory of the ATD head was different between the 2 seats in the sagittal, transverse, and frontal planes.

Conclusion: The results suggest that the overall response of the booster-seated occupant exposed to the same impact conditions was different depending on the seat used regardless of the size of the ATD. The differences observed in the response of the occupants between the 2 seats can be attributed to the differences in cushion stiffness, seat pan geometry, and belt geometry. However, these results were obtained for 2 particular seat models and a specific CRS and therefore cannot be directly extrapolated to the generality of vehicle seats and CRS.     

Restraint use in the Eastern Province of the Kingdom of Saudi Arabia

Objectives: This study set out to examine seat belt and child restraint use in the Dammam Municipality of the Kingdom of Saudi Arabia, based on the premise that an increase in seat belt use would significantly reduce personal injury in traffic crashes. It was expected that local data would help identify intervention strategies necessary to improve seat belt use in the region.

Methods: The research involved 2 methodologies. First, 1,389 face-to-face interviews were conducted with male and female adults in regional shopping plazas regarding their own and their children's restraint use in their vehicles and reasons for these attitudes and beliefs. Second, 2 on-road observation studies of adult and child restraint use were conducted by trained observers. Occupants of approximately 5,000 passenger vehicles were observed while stopped at representative signalized traffic intersections.

Results: The findings showed front seat belt use rates of between 43 and 47% for drivers and 26 to 30% for front seat passengers; rear seat belt use rates were lower. While there seemed to be some knowledge about the purpose and reasons for restraining both adults and children in suitable restraints, this failed to be confirmed in the on-road observations.

Conclusions: Reasons for these rates and findings are discussed fully, and recommendations for improving seat belt use in the Dammam Municipality are included.     

High-risk behaviors while driving: A population-based study from Iran

Objective: Traffic injuries are becoming one of the most important challenges of public health systems. Because these injuries are mostly preventable, the aim of this study is to evaluate the four main high-risk behaviors while driving.

Methods: This cross-sectional study was conducted on a random sample from the population of Mashhad, Iran, in 2014. A checklist and a previously validated questionnaire for the transtheoretical stages of change model (TTM) were used for data collection. Statistical analyses were performed using SPSS 11.5 software with P <.05 statistically significant.

Results: Totally 431 individuals were included with a mean age of 30 ± 11.3 years. Forty-three percent (183) were male. The TTM model revealed that participants were mostly in pre-actional phases regarding not using a cell phone while driving (80%), fastening the driver's seat belt (66%), front seat belt (68%), and rear seat belt (85%) The penalty was a protective factor only for using cellphone (odd ratio [OR] = 0.82, 95% confidence interval [CI], 0.68–0.98). Lower education (OR = 0.12, 95% CI, 0.01–0.94) and male gender (OR = 0.35, 95% CI, 0.14–0.83) were indicative of lower rates of fastening the front and rear seat belts.

Conclusion: The stages of change model among study participants is a proper reflection of the effectiveness of the current policies. More serious actions regarding these high-risk behaviors should be considered in legislation.     

Underutilization of occupant restraint systems in motor vehicle injury crashes: A quantitative analysis from Qatar

Introduction: Restraint systems (seat belts and airbags) are important tools that improve vehicle occupant safety during motor vehicle crashes (MVCs). We aimed to identify the pattern and impact of the utilization of passenger restraint systems on the outcomes of MVC victims in Qatar.

Methods: A retrospective study was conducted for all admitted patients who sustained MVC-related injuries between March 2011 and March 2014 inclusive.

Results: Out of 2,730 road traffic injury cases, 1,830 (67%) sustained MVC-related injuries, of whom 88% were young males, 70% were expatriates, and 53% were drivers. The use of seat belts and airbags was documented in 26 and 2.5% of cases, respectively. Unrestrained passengers had greater injury severity scores, longer hospital stays, and higher rates of pneumonia and mortality compared to restrained passengers (P = .001 for all). There were 311 (17%) ejected cases. Seat belt use was significantly lower and the mortality rate was 3-fold higher in the ejected group compared to the nonejected group (P = .001). The overall mortality was 8.3%. On multivariate regression analysis, predictors of not using a seat belt were being a front seat passenger, driver, or Qatari national and young age. Unrestrained males had a 3-fold increase in mortality in comparison to unrestrained females. The risk of severe injury (relative risk [RR] = 1.82, 95% confidence interval [CI], 1.49–2.26, P = .001) and death (RR = 4.13, 95% CI, 2.31–7.38, P = .001) was significantly greater among unrestrained passengers.

Conclusion: The nonuse of seat belts is associated with worse outcomes during MVCs in Qatar. Our study highlights the lower rate of seat belt compliance in young car occupants that results in more severe injuries, longer hospital stays, and higher mortality rates. Therefore, we recommend more effective seat belt awareness and education campaigns, the enforcement of current seat belt laws, their extension to all vehicle occupants, and the adoption of proven interventions that will assure sustained behavioral changes toward improvements in seat belt use in Qatar.     

Drink driving and risky behavior among university students in southwestern Nigeria—Implications for policy development

Background: Drink driving contributes significantly to road traffic injuries. Little is known about the relationship between drink driving and other high-risk behaviors in non-Western countries. The study aimed to assess the relationship between drink driving and other risky behaviors including making phone calls, sending text messages, nonuse of protective gear, and driving against traffic.

Methods: A cross-sectional survey of risky behavior among undergraduates was conducted. A stratified random sampling method was used to identify young undergraduates who had driven a motorized vehicle in the past year. The Alcohol Use Disorder Identification Test (AUDIT) and other tools developed by researchers were used to identify the risky behaviors.

Results: Of 431 respondents, 10.7% had engaged in drink driving in the past 12 months. The most common risky behavior was making phone calls (63.7%), followed by nonuse of helmets (54.7%), driving against traffic (49.2%), nonuse of seat belts (46.8%), and sending text messages (26.1%). Alcohol use was significantly associated with making phone calls (U = 1.148; P < .0001), sending text messages (U = 1.598; P = .021), nonuse of helmets (U = 1.147; P < .0001), driving against traffic (U = 1.234; P < .0001), and nonuse of seat belts (U = 3.233; P = .001). Drink driving was associated with all risky behaviors except nonuse of seat belts (U = 1.842; P = .065).

Conclusion: Alcohol use and drink driving were associated with multiple risky driving behaviors. This provides useful insight for policy development and presents additional challenges for traffic injury prevention.     

An energy-absorbing sliding seat for reducing neck injury risks in rear impact—analysis for prototype built

Objective: This study investigated overall performance of an energy-absorbing sliding seat concept for whiplash neck injury prevention. The sliding seat allows its seat pan to slide backward for some distance under certain restraint force to absorb crash energy in rear impacts.

Methods: A numerical model that consisted of vehicle interior, seat, seat belt, and BioRID II dummy was built in MADYMO to evaluate whiplash neck injury in rear impact. A parametric study of the effects of sliding seat parameters, including position and cushion stiffness of head restraint, seatback cushion stiffness, recliner characteristics, and especially sliding energy-absorbing (EA) restraint force, on neck injury criteria was conducted in order to compare the effectiveness of the sliding seat concept with that of other existing anti-whiplash mechanisms. Optimal sliding seat design configurations in rear crashes of different severities were obtained. A sliding seat prototype with bending of a steel strip as an EA mechanism was fabricated and tested in a sled test environment to validate the concept. The performance of the sliding seat under frontal and rollover impacts was checked to make sure the sliding mechanism did not result in any negative effects.

Results: The protective effect of the sliding seat with EA restraint force is comparable to that of head restraint–based and recliner stiffness–based anti-whiplash mechanisms. EA restraint force levels of 3 kN in rear impacts of low and medium severities and 6 kN in impacts of high severity were obtained from optimization. In frontal collision and rollover, compared to the nonsliding seat, the sliding seat does not result in any negative effects on occupant protection. The sled test results of the sliding seat prototype have shown the effectiveness of the concept for reducing neck injury risks.

Conclusion: As a countermeasure, the sliding seat with appropriate restraint forces can significantly reduce whiplash neck injury risk in rear impacts of low, medium, and high severities with no negative effects on other crash load cases.     

Rating child passenger safety laws relative to best practice recommendations for occupant protection

Background: State laws regarding child passenger protection vary substantially.

Objectives: The objective of this study was to develop a scoring system to rate child passenger safety laws relative to best practice recommendations for each age of child.

Methods: State child passenger safety and seat belt laws were retrieved from the LexisNexis database for the years 2002–2015. Text of the laws was reviewed and compared to current best practice recommendations for child occupant protection for each age of child.

Results: A 0–4 scale was developed to rate the strength of the state law relative to current best practice recommendations. A rating of 3 corresponds to a law that requires a restraint that is sufficient to meet best practice, and a rating of 4 is given to a law that specifies several options that would meet best practice. Scores of 0, 1, or 2 are given to laws requiring less than best practice to different degrees. The same scale is used for each age of child despite different restraint recommendations for each age. Legislation that receives a score of 3 requires rear-facing child restraints for children under age 2, forward-facing harnessed child restraints for children aged 2 to 4, booster seats for children 5 to 10, and primary enforcement of seat belt use in all positions for children aged 11–13. Legislation requiring use of a “child restraint system according to instructions” would receive a score of 1 for children under age 2 and a 2 for children aged 2–4 because it would allow premature use of a booster for children weighing more than 13.6 kg (30 lb).

Conclusions: The scoring system developed in this study can be used in mathematical models to predict how child passenger safety legislation affects child restraint practices.     

Evaluation of give kids a boost: A school-based program to increase booster seat use among urban children in economically disadvantaged areas

Objective: This study evaluated the effectiveness of a series of 1-year multifaceted school-based programs aimed at increasing booster seat use among urban children 4–7 years of age in economically disadvantaged areas.

Methods: During 4 consecutive school years, 2011–2015, the Give Kids a Boost (GKB) program was implemented in a total of 8 schools with similar demographics in Dallas County. Observational surveys were conducted at project schools before project implementation (P₀), 1–4 weeks after the completion of project implementation (P₁), and 4–5 months later (P₂). Changes in booster seat use for the 3 time periods were compared for the 8 project and 14 comparison schools that received no intervention using a nonrandomized trial process.

The intervention included (1) train-the-trainer sessions with teachers and parents; (2) presentations about booster seat safety; (3) tailored communication to parents; (4) distribution of fact sheets/resources; (5) walk-around education; and (6) booster seat inspections.

The association between the GKB intervention and proper booster seat use was determined initially using univariate analysis. The association was also estimated using a generalized linear mixed model predicting a binomial outcome (booster seat use) for those aged 4 to 7 years, adjusted for child-level variables (age, sex, race/ethnicity) and car-level variables (vehicle type). The model incorporated the effects of clustering by site and by collection date to account for the possibility of repeated sampling.

Results: In the 8 project schools, booster seat use for children 4–7 years of age increased an average of 20.9 percentage points between P₀ and P₁ (P₀ = 4.8%, P₁ = 25.7%; odds ratio [OR] = 6.9; 95% confidence interval [CI], 5.5, 8.7; P < .001) and remained at that level in the P₂ time period (P₂ = 25.7%; P < .001, for P₀ vs. P₂) in the univariate analysis. The 14 comparison schools had minimal change in booster seat use. The multivariable model showed that children at the project schools were significantly more likely to be properly restrained in a booster seat after the intervention (OR = 2.7; 95% CI, 2.2, 3.3) compared to the P₀ time period and compared to the comparison schools.

Conclusion: Despite study limitations, the GKB program was positively associated with an increase in proper booster seat use for children 4–7 years of age in school settings among diverse populations in economically disadvantaged areas. These increases persisted into the following school year in a majority of the project schools. The GKB model may be a replicable strategy to increase booster seat use among school-age children in similar urban settings.     

Predicting vehicle belt fit for children ages 6–12

Objective: To predict shoulder belt fit and lap belt fit as a function of child age, vehicle seat characteristics, and belt geometry.

Methods: In a previous study, the lap belt and shoulder belt fit of 44 children aged 5–12 were measured in a simulated vehicle seat while varying cushion length, cushion angle, seatback angle, and belt anchorage geometry. A regression model was developed to predict lap belt fit and shoulder belt fit as a function of vehicle parameters and child stature. These regression models were applied to the stature distribution of 6- to 12-year-olds using a range of vehicle geometry data to predict the proportion of children expected to achieve good belt fit in the second-row, outboard seating positions of 46 vehicles when not using belt-positioning boosters.

Results: Across the ranges observed in vehicles, lap belt angle had the strongest effect on lap belt fit, although vehicle cushion length also contributed. Shoulder belt fit was most strongly affected by D-ring location. Vehicles with the geometric conditions most suitable for children are estimated to provide good lap belt fit for 25% of children aged 6 to 12. In 20% of vehicles, the shoulder belt is too far inboard for the target child population; 20% of vehicles are estimated to have shoulder belt fit too far outboard for children ages 6 to 12.

Conclusions: Based on this geometric analysis, the rear seats of most vehicles are unlikely to provide good lap belt fit for up to 75% of children ages 6–12. Shoulder belt fit is outside the target range for 40% of children. Consequently, children under 12 years of age are likely to experience markedly poorer belt fit when transitioning out of a booster seat.     

Evaluation of the effectiveness of toe board energy-absorbing material for foot,ankle, and lower leg injury reduction

Objective: Since 2000, numerous improvements have been made to the National Association for Stock Car Auto Racing, Incorporated (NASCAR®) driver restraint system, resulting in improved crash protection for motorsports drivers. Advancements have included seats, head and neck restraints (HNRs), seat belt restraint systems, driver helmets, and others. These enhancements have increased protection for drivers from severe crash loading. Extending protection to the driver's extremities remains challenging. Though the drivers’ legs are well contained for lateral and vertical crashes, they remain largely unrestrained in frontal and frontal oblique crashes.

Method: Sled testing was conducted for the evaluation of an energy-absorbing (EA) toe board material to be used as a countermeasure for leg and foot injuries. Testing included baseline rigid toe boards, tests with EA material–covered toe boards, and pretest positioning of the 50th percentile male frontal Hybrid III anthropomorphic test device (ATD) lower extremities. ATD leg and foot instrumentation included foot acceleration and tibia forces and moments.

Results: The sled test data were evaluated using established injury criteria for tibial plateau fractures, leg shaft fractures, and calcaneus, talus, ankle, and midfoot fractures.

Conclusion: A polyurethane EA foam was found to be effective in limiting axial tibia force and foot accelerations when subjected to frontal impacts using the NASCAR motorsport restraint system.     

Self-regulation of driving speed among distracted drivers: An application of driver behavioral adaptation theory

Objective: The adaptive behavior of mobile phone–distracted drivers has been a topic of much discussion in the recent literature. Both simulator and naturalistic studies suggest that distracted drivers generally select lower driving speeds; however, speed adaptation is not observed among all drivers, and the mechanisms of speed selection are not well understood. The aim of this research was to apply a driver behavioral adaptation model to investigate the speed adaptation of mobile phone–distracted drivers.

Methods: The speed selection behavior of drivers was observed in 3 phone conditions including baseline (no conversation) and hands-free and handheld phone conversations in a high-fidelity driving simulator. Speed adaptation in each phone condition was modeled as a function of secondary task demand and self-reported personal/psychological characteristics with a system of seemingly unrelated equations (SURE) accounting for potential correlations due to repeated measures experiment design.

Results: Speed adaptation is similar between hands-free and handheld phone conditions, but the predictors of speed adaptation vary across the phone conditions. Though perceived workload of secondary task demand, self-efficacy, attitude toward safety, and driver demographics were significant predictors of speed adaptation in the handheld condition, drivers' familiarity with the hands-free interface, attitude toward safety, and sensation seeking were significant predictors in the hands-free condition. Drivers who reported more positive safety attitudes selected lower driving speeds while using phones.

Conclusion: This research confirmed that behavioral adaptation models are suitable for explaining speed adaptation of mobile phone distracted drivers, and future research could be focused on further theoretical refinement.     

Calling,texting, and searching for information while riding a motorcycle: A study of university students in Vietnam

Objective: The objective of this study was to investigate the prevalence of calling, texting, and searching for information while riding a motorcycle among university students and the influences of sociodemographic characteristics, social norms, and risk perceptions on these behaviors.

Methods: Students at 2 university campuses in Hanoi and Ho Chi Minh City, the 2 largest cities in Vietnam, were invited to participate in an anonymous online survey. Data collection was conducted during March and May 2016.

Results: There were 741 respondents, of whom nearly 90% of students (665) were motorcycle riders. Overall prevalence of mobile phone use while riding is 80.9% (95% confidence interval [CI], 77.9–83.9%) with calling having a higher level of prevalence than texting or searching for information while riding: 74% (95% CI, 70.7–77.3%) vs. 51.7% (95% CI, 47.9–55.5%) and 49.9% (95% CI, 46.1–53.7%), respectively. Random parameter ordered probit modeling results indicate that mobile phone use while riding is associated with gender, motorcycle license duration, perceived crash risk, perceived risk of mobile phone snatching, and perceptions of friends' mobile phone use while riding.

Conclusions: Mobile phone use while riding a motorcycle is highly prevalent among university students. Educational programs should focus on the crash and economic risk of all types of mobile phone use while riding, including calling, texting, and searching for information. In addition, they should consider targeting the influence of social norms and peers on mobile phone use while riding.