A method for generating case-specific vehicle models from a single-view vehicle image for accurate pedestrian injury reconstructions

Developing vehicle finite element (FE) models that match real accident-involved vehicles is challenging. This is related to the intricate variety of geometric features and components. The current study proposes a novel method to efficiently and accurately generate case-specific buck models for car-to-pedestrian simulations. To achieve this, we implemented the vehicle side-view images to detect the horizontal position and roundness of two wheels to rectify distortions and deviations and then extracted the mid-section profiles for comparative calculations against baseline vehicle models to obtain the transformation matrices. Based on the generic buck model which consists of six key components and corresponding matrices, the case-specific buck model was generated semi-automatically based on the transformation metrics. Utilizing this image-based method, a total of 12 vehicle models representing four vehicle categories including family car (FCR), Roadster (RDS), small Sport Utility Vehicle (SUV), and large SUV were generated for car-to-pedestrian collision FE simulations in this study. The pedestrian head trajectories, total contact forces, head injury criterion (HIC), and brain injury criterion (BrIC) were analyzed comparatively. We found that, even within the same vehicle category and initial conditions, the variation in wrap around distance (WAD) spans 84-165 mm, in HIC ranges from 98 to 336, and in BrIC fluctuates between 1.25 and 1.46. These findings highlight the significant influence of vehicle frontal shape and underscore the necessity of using case-specific vehicle models in crash simulations. The proposed method provides a new approach for further vehicle structure optimization aiming at reducing pedestrian head injury and increasing traffic safety.

Comparison of single bicycle crashes and collisions among severely injured cyclists-A 16-year analysis based on the Helsinki Trauma Registry (HTR)

OBJECTIVE

The Finnish national Traffic Safety Strategy 2022-2026 seeks to halve the number of road fatalities and serious injuries from 2020 to 2030. The strategy states that better information on bicycle crashes is needed for safety promotion. The aim of this study was to describe the demographics, injury characteristics, alcohol involvement, and helmet use of severely injured cyclists and to compare single bicycle crashes (falling alone or hitting a fixed object) to collisions.

MATERIAL AND METHODS

We identified all bicycle crashes between 2006 and 2021 from the Helsinki Trauma Registry (HTR). Variables analysed were basic patient demographics, Abbreviated Injury Scale (AIS) codes, AIS 3+ injuries, injured body regions, patient Injury Severity Score (ISS) and New Injury Severity Score (NISS), 30-day in-hospital mortality, ICU length of stay, injury mechanism, alcohol use by the injured cyclists, and helmet use.

RESULTS

Of the 325 severe (NISS >15) cycling injury patients in the HTR, 53.5 % were injured in single crashes and 46.5 % in collisions with a moving object. Most (71.4 %) patients were men and mean age of all patients was 54.1 years (SD 16.7). Alcohol was detected in 23.1 % of cases and more often in single crashes (32.8 %) than in collisions (11.9 %). Less than a third (29.2 %) of all cyclists wore a helmet; those who wore a helmet had fewer serious (AIS 3+) head injuries than those who did not. Cyclists injured in collisions had higher ISS and NISS scores than those injured in single crashes. Serious (AIS 3+) injuries in extremities or in pelvic girdle were more common in collisions than in single crashes.

CONCLUSIONS

Among severely injured cyclists, single bicycle crashes were more common; alcohol was more often detected in single bicycle crashes than in collisions. Overall injury severity was higher in collisions than in single crashes. Helmet users had less AIS 3+ head injuries than non-users. Attention should be focused on preventing alcohol-related cycling injuries, promoting use of bicycle helmets, and more precise and comprehensive documentation of bicycle crashes in health care units.

Bicycle-related accidents in Rome: Investigating clinical patterns, demographics, injury contexts, and health outcomes for enhanced public safety

INTRODUCTION

This study aims to analyze the clinical characteristics, demographic features, and injury circumstances of patients admitted to the Emergency Department (ED) at Fondazione Policlinico Universitario A. Gemelli (IRCCS) in Rome, Italy, due to bicycle accidents.

METHODS

Data on clinical characteristics, accident timing, injury circumstances, and helmet use were collected for ED patients involved in bicycle accidents from January 2019 to December 2022. Subsequently, Abbreviated Injury Scale codes of all diagnoses were recorded and the Injury Severity Score was calculated.

RESULTS

Over the study period, 763 patients were admitted to the ED following bicycle accidents, with a 0.3 % fatality rate and a 30.4 % frequency of multitrauma. Multivariate analysis revealed that collisions with other vehicles increased trauma severity and the risk of ICU admission. Conversely, helmet use was associated with reduced severity of head trauma and a lower likelihood of ICU admission. Notably, toxicological investigations were not conducted for any ED-admitted patients.

CONCLUSIONS

Although a low mortality rate and a low incidence of multi-trauma have been shown in comparison to other nations, it is necessary to adopt prevention strategies like safety devices, more cycle paths, and better infrastructures on the one hand, and stricter laws on the other. It is essential to require toxicological testing in Italy for all accidents involving this means of transport, and to make helmet use compulsory for all ages.

An Assessment of Sikh Turban's Head Protection in Bicycle Incident Scenarios

Due to religious tenets, Sikh population wear turbans and are exempted from wearing helmets in several countries. However, the extent of protection provided by turbans against head injuries during head impacts remains untested. One aim of this study was to provide the first-series data of turbans' protective performance under impact conditions that are representative of real-world bicycle incidents and compare it with the performance of bicycle helmets. Another aim was to suggest potential ways for improving turban's protective performance. We tested five different turbans, distinguished by two wrapping styles and two fabric materials with a size variation in one of the styles. A Hybrid III headform fitted with the turban was dropped onto a 45 degrees anvil at 6.3 m/s and head accelerations were measured. We found large difference in the performance of different turbans, with up to 59% difference in peak translational acceleration, 85% in peak rotational acceleration, and 45% in peak rotational velocity between the best and worst performing turbans. For the same turban, impact on the left and right sides of the head produced very different head kinematics, showing the effects of turban layering. Compared to unprotected head impacts, turbans considerably reduce head injury metrics. However, turbans produced higher values of peak linear and rotational accelerations in front and left impacts than bicycle helmets, except from one turban which produced lower peak head kinematics values in left impacts. In addition, turbans produced peak rotational velocities comparable with bicycle helmets, except from one turban which produced higher values. The impact locations tested here were covered with thick layers of turbans and they were impacted against flat anvils. Turbans may not provide much protection if impacts occur at regions covered with limited amount of fabric or if the impact is against non-flat anvils, which remain untested. Our analysis shows that turbans can be easily compressed and bottom out creating spikes in the headform's translational acceleration. In addition, the high friction between the turban and anvil surface leads to higher tangential force generating more rotational motion. Hence, in addition to improving the coverage of the head, particularly in the crown and rear locations, we propose two directions for turban improvement: (i) adding deformable materials within the turban layers to increase the impact duration and reduce the risk of bottoming out; (ii) reducing the friction between turban layers to reduce the transmission of rotational motion to the head. Overall, the study assessed Turbans' protection in cyclist head collisions, with a vision that the results of this study can guide further necessary improvements for advanced head protection for the Sikh community.

Injury patterns and outcomes in motorcycle driver crashes in the United States: The effect of helmet use

BACKGROUND

Motorcycle crashes pose a persistent public health problem with disproportionate rates of severe injuries and mortality. This study aims to analyze injury patterns and outcomes with regard to helmet use. We hypothesized that helmet use is associated with fewer head injuries and does not increase the risk of cervical spine injuries.

METHODS

The National Trauma Data Bank was queried for all motorcycle driver crashes between 2007-2017. Univariable analysis was used to compare demographics, clinical data, injury patterns using abbreviated injury scale, and outcomes between helmeted motorcycle drivers and non-helmeted motorcycle drivers who were injured in traffic crashes. Independent factors associated with mortality were determined by regression analysis after adjustment for potential confounders.

RESULTS

A total of 315,258 patients were included for analysis, 66 % of these patients were helmeted. The sample was 92.5 % male and the median age was 41 years. Non-helmeted motorcycle drivers were more likely to sustain severe head trauma (head abbreviated injury scale ≥ 3: 28.5 % vs. 13.3 %, p < 0.001), had higher intensive care unit-admission (38 % vs. 30.2 %, p<0.001), mechanical ventilation (20.1 % vs. 13 %, p<0.001) and overall mortality rates (6.2 % vs. 3.9 %, p<0.001). Cervical spine injuries occurred in 10.6 % of non-helmeted motorcycle drivers and in 9.5 % of helmeted motorcycle drivers (p<0.001). Helmet use was identified as an independent factor associated with lower mortality [OR 0.849 (0.809-0.891), p<0.001].

CONCLUSION

Helmet use is protective for severe head injuries and associated with decreased mortality. Helmet use was not associated with increased rates of cervical spine injuries. On the contrary, fewer injuries were observed in helmeted motorcycle drivers. Public health initiatives should be aimed at enforcement of universal helmet laws within the United States and across the world.

Evaluation of an Elastomeric Honeycomb Bicycle Helmet Design to Mitigate Head Kinematics in Oblique Impacts

Head impacts in bicycle accidents are typically oblique to the impact surface and transmit both normal and tangential forces to the head, causing linear and rotational head kinematics, respectively. Traditional expanded polystyrene (EPS) foam bicycle helmets are effective at preventing many head injuries, especially skull fractures and severe traumatic brain injuries (TBIs) (primarily from normal contact forces). However, the incidence of concussion from collisions (primarily from rotational head motion) remains high, indicating need for enhanced protection. An elastomeric honeycomb helmet design is proposed herein as an alternative to EPS foam to improve TBI protection and be potentially reusable for multiple impacts, and tested using a twin-wire drop tower. Small-scale normal and oblique impact tests showed honeycomb had lower oblique strength than EPS foam, beneficial for diffuse TBI protection by permitting greater shear deformation and had the potential to be reusable. Honeycomb helmets were developed based on the geometry of an existing EPS foam helmet, prototypes were three-dimensional-printed with thermoplastic polyurethane and full-scale flat and oblique drop tests were performed. In flat impacts, honeycomb helmets resulted in a 34% higher peak linear acceleration and 7% lower head injury criteria (HIC15) than EPS foam helmets. In oblique tests, honeycomb helmets resulted in a 30% lower HIC15 and 40% lower peak rotational acceleration compared to EPS foam helmets. This new helmet design has the potential to reduce the risk of TBI in a bicycle accident, and as such, reduce its social and economic burden. Also, the honeycomb design showed potential to be effective for repetitive impact events without the need for replacement, offering benefits to consumers.

Evaluating child helmet protection and testing standards: A study using PIPER child head models aged 1.5, 3, 6, and 18 years

The anatomy of children's heads is unique and distinct from adults, with smaller and softer skulls and unfused fontanels and sutures. Despite this, most current helmet testing standards for children use the same peak linear acceleration threshold as for adults. It is unclear whether this is reasonable and otherwise what thresholds should be. To answer these questions, helmet-protected head responses for different ages are needed which is however lacking today. In this study, we apply continuously scalable PIPER child head models of 1.5, 3, and 6 years old (YO), and an upgraded 18YO to study child helmet protection under extensive linear and oblique impacts. The results of this study reveal an age-dependence trend in both global kinematics and tissue response, with younger children experiencing higher levels of acceleration and velocity, as well as increased skull stress and brain strain. These findings indicate the need for better protection for younger children, suggesting that youth helmets should have a lower linear kinematic threshold, with a preliminary value of 150g for 1.5-year-old helmets. However, the results also show a different trend in rotational kinematics, indicating that the threshold of rotational velocity for a 1.5YO is similar to that for adults. The results also support the current use of small-sized adult headforms for testing child helmets before new child headforms are available.

Effect of helmet use on maxillofacial injuries due to bicycle and scooter accidents: a systematic literature review and meta-analysis

Maxillofacial injury is a common injury resulting from bicycle (including e-bike) and scooter accidents. With 80,000 admissions to emergency departments in 2019, bicycle accidents account for more than half of all traffic-related emergency department visits in the Netherlands. The United States reports approximately 130,000 injuries and 1000 fatalities related to cycling annually. This systematic review and meta-analysis was performed to examine the protective effect of helmets against maxillofacial injuries resulting from bicycle and scooter (including e-bike and e-scooter) accidents. After a systematic literature search, 14 studies were found to be eligible for this systematic review. Of these, 11 were included in the meta-analysis. None of the included studies focused on vehicles with motors (e-bikes and e-scooters); all focused only on non-motorized vehicles. All included studies were non-randomized, which could have led to bias in the pooled results. Data from the included studies were tested for heterogeneity using the binary random-effects model (DerSimonian-Laird method), and the odds ratio for the occurrence of maxillofacial injury in cyclists wearing a helmet versus those not wearing a helmet was calculated by random-effects meta-analysis. Patients who had worn a helmet suffered significantly fewer maxillofacial injuries than patients who had not, in bicycle accidents (odds ratio 0.682). In conclusion, wearing a helmet has a significant protective effect against maxillofacial injury, indicating the need for strict helmet legislation.

The Effectiveness of Parenting Programs in Preventing Abusive Head Trauma: A Systematic Review and Meta-Analysis

Parenting programs are the most common intervention for preventing the lethal form of child maltreatment, abusive head trauma (AHT). However, certain results of the effects of these programs have not yet been compared across studies. A systematic review with meta-analysis is warranted to quantitively synthesize the available evidence to identify effective elements and strategies of the programs for preventing AHT. This review aims to estimate AHT preventive parenting programs' pooled effect on the reduction of AHT incidence, the improvement of parental knowledge, and the increased use of safe strategies in response to infants' inconsolable crying. Studies published in English and Mandarin were searched and retained if they were randomized control trials (RCTs) or with a quasi-experimental design, included an AHT preventive parenting program, and provided data that quantified targeted outcomes. Eighteen studies were included in this review. AHT preventive parenting programs had a pooled effect on improving parents' knowledge and increasing the use of safe coping strategies in response to inconsolable crying but not on the incidence of AHT and parents' emotional self-regulation. Subgroup analyses showed that the intervention effects were mostly present across study designs or measurements and emerged in the reduction of AHT incidence compared with historical controls. The findings suggest that AHT preventive parenting programs enhance parenting knowledge and skills to provide safe care for infants. Further efforts to evaluate AHT parenting programs on the reduction of AHT incidence are necessary for decision-making on allocating and disseminating interventions.

Computer vision-based helmet use registration for e-scooter riders - The impact of the mandatory helmet law in Copenhagen

PROBLEM

E-scooters are a new form of mobility used more frequently in urban environments worldwide. As there is evidence of an increased risk of head injuries, helmets are recommended and (less frequently) legislated. Denmark has enacted mandatory e-scooter helmet use legislation from January 1, 2022. So far, it is unclear how this newly implemented law influenced helmet use of e-scooter riders in Denmark immediately after its implementation.

METHOD

In this observational study, we register and compare e-scooter helmet use before the mandatory helmet use legislation (December 2021) and after (February 2022). As observational survey data collection in the field can be highly time-consuming, we conducted a video-based observation survey. We trained and applied a computer vision algorithm to automatically register e-scooter helmet use in the video data.

RESULTS

The trained algorithm produces accurate helmet use data, which does not differ significantly from human-registered helmet use. In applying the algorithm to video data collected in December 2021 and February 2022, we register an overall e-scooter helmet use of 4.4% in n = 1054 riders. Splitting the observation between the time before and after the implementation of the helmet use law reveals a significant increase in helmet use from 1.80% to 5.56%.

DISCUSSION

In this study, we successfully train and apply an object detection algorithm to register accurate helmet use data in videos collected in Copenhagen, Denmark. Using this algorithm, we find a significant impact of a new mandatory e-scooter helmet use law on e-scooter riders' helmet use behavior. Limitations of the study as well as future research needs, are discussed.

PRACTICAL APPLICATIONS

Computer vision algorithms can be used for accurate e-scooter helmet assessments. Implementing a mandatory helmet use law can increase helmet use of e-scooters at specific observation sites.

The forgotten protection factor: A nationwide score-based assessment of motorcycle eye protection legislation

INTRODUCTION

Motorcycle accidents cause millions of deaths and injuries globally. It is estimated that billions of dollars would be saved in the United States alone if safety equipment, such as helmets and eye protection, was ubiquitously worn. Legislation concerning eye protection specifically is understudied and poorly characterized.

METHOD

We reviewed all motorcycle-related safety equipment laws in all 50 states of the United States for information regarding eye protection. We graded the rigor of each statute using our six-category Eye Safety Metric and performed a comparative analysis of statutes across all jurisdictions.

RESULTS

Fourteen states did not have any statutes regarding eye protection. Among states that did, 23 states had weak statutes (0-2 points), 20 states had moderately stringent statutes (3-4 points), and 7 states had strong statutes (5-6 points). States in western United States tended to have less strict eye protection laws. Twenty-six states had eye protection exemptions for windshields, which are a poor form of eye protection. Six states that had universal helmet laws had no laws requiring eye protection.

CONCLUSIONS

We characterized eye protection legislation across the country and found great diversity in the stringency of laws across all jurisdictions. Despite only two states lacking helmet laws, we found that 14 states lacked eye protection laws. These findings from our Eye Safety Metric can be used as a springboard for future research, which can be used to determine the need for and significance of eye safety legislation for motorcyclists and to inform legislative decision-making.

PRACTICAL APPLICATIONS

With this research, we hope to further the understanding of legislation regarding eye protection for motorcyclists and help policymakers identify states that need improved eye safety standards.

Injury Pattern and Outcomes Following All-Terrain Vehicle Accidents in Kentucky Children: A Retrospective Study

PURPOSE

All-terrain vehicles (ATVs) pose a significant risk for morbidity and mortality amongst children. We hypothesize that current vague legislation regarding helmet use impacts injury patterns and outcomes in pediatric ATV accidents.

METHODS

The institutional trauma registry was queried for pediatric patients involved in ATV accidents from 2006 to 2019. Patient demographics and helmet wearing status were identified in addition to patient outcomes, such as injury pattern, injury severity score, mortality, length of stay, and discharge disposition. These elements were analyzed for statistical significance.

RESULTS

720 patients presented during the study period, which were predominantly male (71%, n = 511) and less than 16 years old (76%, n = 543). Most patients were not wearing a helmet (82%, n = 589) at time of injury. Notably, there were 7 fatalities. A lack of helmet use is positively associated with head injury (42% vs 23%, P < .01), intracranial hemorrhage (15% vs 7%, P = .03), and associated with lower Glasgow Coma Scale (13.9 vs 14.4, P < .01). Children 16 years and older were least likely to wear a helmet and most likely to incur injuries. Patients over 16 years had longer lengths of stay, higher mortality, and higher need for rehabilitation.

CONCLUSION

Not wearing a helmet is directly correlated with injury severity and concerning rates of head injury. Children 16 years and older are at greatest risk for injury, but younger children are still at risk. Stricter state laws regarding helmet use are necessary to reduce pediatric ATV-related injury burden.

LEVEL OF EVIDENCE

level III retrospective comparative study.

Two Minutes for Roughing: A National Analysis of Ice Hockey Injuries from American Trauma Centers

BACKGROUND

Hockey is a high-impact sport that carries a risk of injury. No national-level studies defining the burden of injury in this sport have yet been performed. This study sought to analyze patient demographics, injury types and severity, and outcomes after trauma sustained while playing hockey.

METHODS

Retrospective analysis of hockey-related injuries was performed using the National Trauma Data Bank (NTDB) (2007-2018). Patients were identified based on ICD-9 and -10 codes without exclusions. Demographics, clinical/injury data, and outcomes were examined using univariate analysis. Subgroup analysis was performed by patient sex.

RESULTS

Hockey injuries (n = 306) comprised <1% of the NTDB. Median age was 15 years [IQR 13-25] (range 5-71). Most patients (n = 279, 91%) were male. Lower extremities were the most frequently injured body region (n = 88, 29%). Head injuries occurred in 19% (n = 57). Facial injuries occurred in 6% (n = 17). Tooth loss was infrequent (n = 2, 1%). One (<1%) death occurred after a hockey-related brain injury. Clinical/injury data between male and female hockey players were comparable apart from a significantly higher rate of upper extremity fractures among the female cohort (22% vs 4%, P < .001).

CONCLUSION

Perceptions that hockey players may frequently sustain head, face, and tooth injuries from collisions, fighting, or stick/puck impacts were not supported by this national-level study, in which lower extremity fractures were the most common injury. While hockey injury prevention equipment has primarily focused on head/face protection (eg, helmets and mouthguards), this analysis suggests increased focus on extremity protective measures is warranted.

Increased bicycle helmet use in the absence of mandatory bicycle helmet legislation: Prevalence and trends from longitudinal observational studies on the use of bicycle helmets among cyclists in Denmark 2004-2022

INTRODUCTION

Using a bicycle helmet reduces the risk of serious head injuries among cyclists substantially. This makes it highly relevant to increase the use of helmets and to measure the prevalence of bicycle helmet use over time and across different groups.

METHOD

Since 2004, the use of bicycle helmets in Denmark has been measured observationally in two nationwide time series: one among cyclists in city traffic across all age groups, and one among cycling school children (aged 6-16) around schools. The observations have been conducted on a regular basis in different parts of the country following the same methodology over the years.

RESULTS

Bicycle helmet use among cyclists in city traffic in Denmark has increased from 6% in 2004 to 50% in 2022. Among cycling school children, helmet use has increased from 33% in 2004 to 79% in 2022. Throughout the years, helmet wearing rates have been highest among young children and lowest among young adults. Since 2015, female cyclists in city traffic have had a slightly higher helmet use than male cyclists.

DISCUSSION

Several factors might have affected bicycle helmet use in Denmark. One possible factor is a nationwide focus on traffic safety education and behavior change campaigns to encourage helmet wearing. Furthermore, among stakeholders on cycling safety there has been consensus on recommending bicycle helmet use and supporting the promotion of helmets while not recommending or promoting helmet legislation. Finally, more safety-oriented behavior in road traffic in general, and self-reinforcing effects of increased helmet use have plausibly been important factors.

PRACTICAL APPLICATIONS

Increasing bicycle helmet use in a country where cycling is popular is possible in the absence of mandatory bicycle helmet legislation. Persistent behavior change campaigning and education, stakeholder consensus, higher levels of road safety-oriented behaviors, and self-reinforcing processes could potentially be important factors.

Head Flail Corridors From Sled Impact Acceleration Tests for Use in Occupant-Centric Vehicle Design

INTRODUCTION

In aircraft crashes, injuries to the head and upper torso are frequently reported, with head injury reported most frequently of all body regions. Because preventing flail of the head and body is of utmost importance for occupant survival, the Aircraft Crash Survival Design Guide (ACSDG), the guide to crashworthy aircraft design, published flail envelopes. However, the ACSDG flail envelopes are based on a single test with an anthropomorphic test device subjected to a frontal acceleration. In this article, human research volunteer (HRV) response data are used to calculate head flail corridors and evaluate the ACSDG flail envelopes.

MATERIALS AND METHODS

Data from HRV sled tests were obtained from the historical Naval Biodynamics Laboratory collection of the Biodynamics Data Resource. Digitized high-speed film for each test was tracked and processed to represent the head flail response in a format amenable to corridor development. Time-based and position-based head flail corridors were developed for groups of exposure-matched tests and then compared to the ACSDG flail envelopes.

RESULTS

A collection of 714 HRV sled tests conducted in six different impact directions ranging from 3 to 15 g was used to develop time-based and position-based head flail corridors for 39 match groups. The ACSDG vertical limit and anteroposterior limit and curve were not exceeded by the flail corridors, but the lateral limit and curve were exceeded by 4.6 cm to 15.8 cm.

CONCLUSIONS

The flail corridors provide a useful baseline for representing the well-restrained occupant response at lower, non-injurious exposure levels and across multiple impact directions. Under these conditions, the ACSDG lateral limit and curve are not adequate. At higher exposure levels or with modified restraints, seating, or equipment, the ACSDG vertical limit and anteroposterior limit and curves may also be inadequate.

Nationwide Analysis of Motorcycle-Associated Injuries and Fatalities in the United States: Insufficient Prevention Policies or Abandoned Laws?

BACKGROUND

Motorcycle road traffic collisions are a major cause of mortality in the United States. We aimed to analyze the temporal and statewide trends in motorcycle collision fatalities (MCFs) nationwide and their association with state laws regarding motorcycle helmet requirements, lane splitting, speeding, intoxicating driving, and red light cameras.

METHODS

A retrospective review of United States MCF/capita from 2015 to 2019 was performed using the Fatality Analysis Reporting System database. MCF/capita was defined as a motorcyclist death per 100 000 motorcyclist registrations. Independent-samples t-test and ANOVA were used to determine differences, with significance defined as P < .05. Linear regression analysis and Pearson's correlation were used to further determine associations between variables.

RESULTS

The majority of fatalities occurred in males (n = 21 354, 91.0%), ages 25-54 (n = 13 728, 58.5%), and Caucasians (n = 19 195, 81.8%). A total of 24 states and DC exhibited positive trends in MCF/capita from 2015 to 2019. There was no significant difference in MCF/capita between states who had mandatory helmet laws for all, partial requirements, and states with no law (63.4 vs 54.3 vs 33.6, P = .360). Among fatalities involving alcohol, a significantly greater number of MCF/capita were found above the legal limit of .08 compared to the group with a blood alcohol concentration of .01-.07 (17.8 vs 4.5, P < .001).

CONCLUSION

Motorcyclist fatalities continue to pose a public health risk, with 24 states showing an upward trend. Additional interventions and laws are needed to decrease the number of motorcyclist deaths. Further strategy on implementation and enforcement of helmet laws and alcohol consumption may be an essential component.

Electric scooter-related accidents: a possible protective effect of helmet use on the head injury severity

Despite electric scooter use has proliferated in Italy since 2019, actionable data regarding injury incidence and patterns associated with electric scooter accidents are limited. This study aims at analyzing the rate, clinical, and demographic features of electric scooter accidents accessed to the Emergency Department (ED) of Fondazione Policlinico Universitario A. Gemelli IRCSS (Rome, Italy). This retrospective study included all patients older than 18 years riding an electric scooter in the ED from June 2019 to April 2022. Personal data, injury circumstances, helmet use, and health data were collected. Abbreviated Injury Scale (AIS) codes of all diagnoses were recorded, and the Injury Severity Score (ISS) was calculated for each patient. The analysis includes 92 patients admitted to the ED due to an e-scooter accident during the study period, with an increase in years. Thirty-two patients presented bone fractures especially concerning the extremities and the face districts. The median Injury Severity Score in the study cohort was 3, with the highest AIS represented by AIS Pelvic-Extremity and AIS External. Moreover, statistical significance was found between AIS Head-Neck and severity of trauma. E-scooters have become a familiar sight in cities worldwide recently, with many new companies renting them for use. But their arrival has also brought new safety concerns. Although most injuries reported are minor, the meager rate of helmet use is critical. Implementing compulsory helmet use for electric scooters for all ages could be a protective factor for being patient with head trauma on urban streets.

Head Impact in Blind Football During the Tokyo Paralympics: Video-Based Observational Study

ABSTRACT

Head impacts during blind football are common and have high injury rates; however, their characteristics and impact are still underreported. We compared head impact characteristics in blind football players with and without falls on all 18 official blind football match videos from the Tokyo 2020 Paralympic games. The rate of head impacts with falls was significantly higher in the preliminary phase, offense phase, and during dribbling. Significant differences in the region of the head impacted were also observed among the impact subjects/objects. The findings in this study would contribute to the development of injury prevention measures to minimize head injuries from head impact in blind football.

Comparison of the effectiveness of rotating seats in autonomous vehicles and airbags in traditional vehicles to minimize head injuries in frontal crash

We analyzed and compared the effectiveness of the rotating seat of autonomous vehicles and that of an airbag in traditional vehicles as head protection measures in a frontal crash. Driver frontal crash models of traditional and autonomous vehicles and a head finite element model were established. Four evaluation indexes were used for comparison. The airbag proved more effective than seat rotation in terms of injury criteria and brain tissue injury risk under frontal crash conditions with and without brake involvement. A segmented protection measure based on crash acceleration values is proposed to improve crash safety in future autonomous vehicles.

Effectiveness of Wearable Protection Equipment for Seated Pedestrians

This study used finite element models to investigate the efficacy of seated pedestrian protection equipment in vehicle impacts. The selected safety equipment, a lap belt, an airbag vest, and a bicycle helmet, were chosen to mitigate the underlying biomechanical causes of seated pedestrian injuries reported in the literature. The impact conditions were based on the three most dangerous impact scenarios from a previous seated pedestrian impact study. Serious injury (AIS 3+) risks were compared with and without protective equipment. A 50th percentile male occupant model and two generic vehicle models, the family car (FCR) and sports utility vehicle (SUV), were used to simulate vehicle collisions. Three impact conditions were run with every combination of protective equipment (n = 24). The helmet reduced head and brain injury risks from the vehicle-head and ground-head contacts. The airbag reduced the head injury risk in the FCR vehicle-head contact but increased the brain injury risks in the SUV impacts from increased whiplash. The lap belt increased head injury risks for both the FCR and the SUV impacts because it created a stronger FCR vehicle-head contact and SUV ground-head contact. When the belt and airbag were used together the head injury risks dramatically decreased because the pedestrian body impacted the ground arm or leg first and slowly rolled onto the ground which resulted in softer ground-head contacts and in two instances, no ground-head contact. Only the helmet proved effective in all impact conditions. Future testing must be completed before recommending the belt or airbag for seated pedestrians.

Comparison of Head Strike Incidence under K1 Rules of Kickboxing with and without Helmet Protection-A Pilot Study

BACKGROUND

Kickboxing is a combat sport that encompasses various forms of competition. K1 kickboxing is conducted without any restrictions on the force of strikes, and the bout can end prematurely through a knockout. Headgear has been introduced in amateur kickboxing to safeguard the head. However, scientific studies have shown that despite their use, serious head injuries can still occur. The aim of this study was to evaluate the temporal structure of the bout by calculating the number of head strikes in K1 kickboxing bouts with and without headgear.

METHODS

Thirty K1 kickboxing bouts were analyzed, with 30 participants included in the study. The fights were conducted according to the World Association Kickboxing Organization (WAKO) rules. The bouts consisted of three rounds of 2 min each, with a 1 min break between rounds. Sparring pairs were arranged according to weight categories. The first bouts were conducted without headgear, and two weeks later, the fights were repeated with WAKO-approved headgear. The number of head strikes was assessed retrospectively by analyzing video recordings of the bouts, categorizing strikes as hand or foot strikes, and differentiating between strikes that hit the head directly or indirectly.

RESULTS

The results showed statistically significant differences between bouts with and without headgear in terms of the number of strikes to the head (p = 0.002), strikes directly to the head (p < 0.001), all hand strikes to the head (p = 0.001), hand strikes directly to the head (p = 0.003), and foot strikes directly to the head (p = 0.03). Higher values were observed in bouts with headgear.

CONCLUSIONS

Headgear increases the probability of direct strikes to the head. Therefore, it is important to familiarize kickboxers with the use of headgear in their sport to minimize head injuries.

Head-ground impact conditions and helmet performance in E-scooter falls

OBJECTIVE

Head injuries are common injuries in E-scooter accidents which have dramatically increased in recent years. The head impact conditions and helmet performance during E-scooter accidents are barely investigated. This study aims to characterize the head-ground impact biomechanics and evaluate bicycle helmet protection in typical E-scooter falls.

METHOD

The finite element (FE) model of a hybrid III dummy riding an E-scooter was developed and validated. The FE model with and without a bicycle helmet was used to reproduce twenty-seven E-scooter falls caused by the collision with a curb, in which different riding speeds (10, 20, and 30 km/h), curb orientations (30, 60, and 90°), and E-scooter orientations (-15, 0, and 15°) were simulated. Head-ground impact velocities and locations were evaluated for the unhelmeted configurations while the helmet performance was evaluated with the reduction of head injury metrics.

RESULTS

E-scooter falls always resulted in an oblique head-ground impact, with 78 % on the forehead. The mean vertical and tangential head-ground impact velocities were respectively 5.7 ± 1.5 m/s and 3.7 ± 2.0 m/s. The helmet significantly (p < 0.1) reduced the head linear acceleration, angular velocity, HIC_36, and BrIC, but not the angular acceleration. However, even with the helmet, the head injury metrics were mostly above the thresholds of severe head injuries.

CONCLUSION

Typical E-scooter falls might cause severe head injuries. The bicycle helmet was efficient to reduce head injury metrics but not to prevent severe head injuries. Future helmet standard evaluations should involve higher impact energy and the angular acceleration assessment in oblique impacts.

Experimental research of energy absorbing structures within helmet samples made with the additive manufacturing method - preliminary study

PURPOSE

This study aimed to develop an energy-absorbing structure for bicycle helmets to minimize head injuries caused by collisions. The research team explored three geometric structures produced through additive methods and compares their energy absorption properties with a standard bicycle helmet made of Expanded Polystyrene (EPS) foam.

METHODS

The study prepared samples of three geometric structures (a ball, a honeycomb and a conical shape) and a fragment of a bicycle helmet made of EPS foam with the same overall dimensions. Laboratory tests were conducted using a pneumatic hammer, piston compressor, anvil, triaxial accelerometer and data processing systems. Three crash tests were performed for each type of structure, and the anvil's maximum acceleration and stopping distance after the crash were analyzed.

RESULTS

The study found that the energy absorption properties of the Polylactic Acid (PLA) material printed with the incremental method were comparable or better than those of the EPS material used in helmets. The geometric structure of the energy-absorbing material played a crucial role in its effectiveness. The most promising results were obtained for the ball samples.

CONCLUSIONS

The study concluded that further research on energy-absorbing structures made using the Fused Deposition Modeling (FDM) method could be useful in the production of bicycle helmets. The results show that the geometric structure of the energy-absorbing material is a crucial factor in its effectiveness. The findings suggest that the ballshaped structure made with PLA material printed using the incremental method could be a promising design for bicycle helmets to minimize head injuries caused by collisions.

Educational interventions to prevent paediatric abusive head trauma in babies younger than one year old: A systematic review and meta-analyses

BACKGROUND

Paediatric abusive head trauma (AHT) occurs in young children due to violent shaking or blunt impact. Educational and behavioural programmes modifying parent/infant interactions may aid primary prevention. This systematic review aims to assess the effectiveness of such interventions to prevent AHT in infants.

METHODS

We searched Embase, MEDLINE, PsycINFO, The Cochrane library, CINAHL databases and trial registries to September 2021, for studies assessing the effectiveness of educational and behavioural interventions in preventing AHT. Eligible interventions had to include messaging about avoiding or dangers of infant shaking. Randomised controlled trials (RCTs) reporting results for primary (AHT, infant shaking) or secondary outcomes (including parental responses to infant crying, mental wellbeing), and non-randomised studies (NRSs) reporting primary outcomes were included. Evidence from combinable studies was synthesised using random-effects meta-analyses. Certainty of evidence was assessed using GRADE framework. PROSPERO registration CRD42020195644.

FINDINGS

Of 25 identified studies, 16 were included in meta-analyses. Five NRSs reported results for AHT, of which four were meta-analysed (summary odds ratio [OR] 0.95, 95 % confidence intervals [CI] 0.80-1.13). Two studies assessed self-reported shaking (one cluster-RCT, OR 0.11, 95 % CI 0.02-0.53; one cohort study, OR 0.36, 95 % CI 0.20-0.64, not pooled). Meta-analyses of secondary outcomes demonstrated marginal improvements in parental response to inconsolable crying (summary mean difference 1.58, 95 % CI 0.11-3.06, on a 100-point scale) and weak evidence that interventions increased walking away from crying infants (summary incidence rate ratio 1.52, 95 % CI 0.94-2.45). No intervention effects were found in meta-analyses of parental mental wellbeing or other responses to crying.

INTERPRETATION

Low certainty evidence suggests that educational programmes for AHT prevention are not effective in preventing AHT. There is low to moderate certainty evidence that educational interventions have no effect or only marginally improve some parental responses to infant crying.

Prediction of Helmet Use Behavior among Motorcyclists Based on the Theory of Planned Behavior

BACKGROUND

Road traffic injuries (RTIs) are one of the most critical factors that endanger human health. More specifically, head and neck injuries are the main causes of deaths and disabilities among motorcyclists. This study aimed to investigate the predictive factors of helmet use behavior among motorcyclists based on the theory of planned behavior (TPB).

STUDY DESIGN

This study followed the cross-sectional design.

METHODS

This study was conducted on randomly selected 730 motorcyclist employees in Qom, Iran, in 2021. The data collection tool was a self-administered researcher-made questionnaire, including items on demographic characteristics, history of RTIs, and constructs of TPB. Data were analyzed using descriptive summary statistics, analysis of variance, independent samples t test, Pearson correlation coefficient, and structural equation modeling (SEM).

RESULTS

In this study, only 9.8% of the participants reported that they always used a helmet while riding a motorcycle. About 60% reported a history of a motorcycle crash, and 11.5% had a history of head injuries. The direct effect of attitude, subjective norms, and perceived behavioral control on the intention to use a helmet were statistically significant, explaining 59% of the variation in behavioral intention (intention to use a helmet) (R2=0.59). Moreover, perceived behavioral control and behavioral intention had significant effects on helmet use behavior (R2=0.26).

CONCLUSION

The prevalence of helmet use among the studied population was very low. Moreover, TPB was useful in identifying the determinants of behavior and especially behavioral intention of helmet use among motorcyclists.

Traumatic Brain Injury in Underage Motorcycle Drivers: Clinical Outcomes and Sociocultural Attitudes from a Lower-Middle-Income Country

BACKGROUND AND OBJECTIVE

Poor societal attitudes and inadequate law enforcement have greatly contributed to the increase in underage motorcycle driving in Pakistan. This study reports the burden of traumatic brain injury (TBI), clinical characteristics/outcomes, and reason for driving in underage motorcyclists.

MATERIALS AND METHODS

A prospective study was conducted throughout 2021. Demographics, mechanism of injury, helmet use, number of passengers, clinical outcomes, reason for driving and parental awareness/consent status, referral pathway, and transport duration were documented.

RESULTS

Of a total of 1052 motorcyclists with TBI, 112 were underage drivers. The mean age was 14.7 years (range, 10-17 years); 98.2% were male and 17% wore protective helmets. The most common reason for driving was recreational, followed by for domestic chores. In 66 patients, there was parental awareness and 30 of these patients had active parental consent. These patients reported domestic chores as the reason for their journey, whereas recreational purposes were a more prevalent reason in patients without parental awareness/consent (P < 0.001). Most patients were brought by provincial ambulance service (response time 12.8 minutes). Some patients came from peripheral hospitals (26.8%) and private hospitals (14.3%) that lacked neurosurgical cover, and these were associated with severer baseline injuries (P < 0.001). The average stay was 6.5 days, and 75.9% of patients were discharged with a good Glasgow Outcome Scale score.

CONCLUSIONS

Most underage patients with TBI resulting from motorcycle driving are adolescent boys who do not use helmets. Trauma prevention systems and involvement of multiple stakeholders are needed to reduce underage driving. Efficient referral systems must transport patients to appropriate neurosurgical cover, which is lacking outside major cities.

A computational study on the basis for a safe speed limit for bicycles on shared paths considering the severity of pedestrian head injuries in bicyclist-pedestrian collisions

Bicyclists and pedestrians are two large vulnerable groups of road users. Many cities have allowed cyclists to share space with pedestrians on footpaths and off-road paths to reduce conflict with motor vehicles. The risk of bicyclist-pedestrian accidents is also increasing accordingly. Therefore, there is a need to understand the factors that affect the risk of injury in such accidents, especially to pedestrians who are considered more vulnerable. This paper presents a detailed investigation of bicyclist-pedestrian collisions and possible injury outcomes. The study has considered five levels of collision speed ranging from 10 km/h to 30 km/h, three pedestrian profiles (adult, child, and elderly) differentiated by their weight and height, three bicycles with different masses, and five impact directions. The bicyclist-pedestrian collision simulations have been analyzed based on four metrics: throw distance, peak head velocity on impact with the ground, head injury criterion (HIC) value, and the probability of severe head injury. For each simulation, the throw distance and peak head velocity on impact with the ground are extracted. Following that, the HIC and the probability of severe head injury to pedestrians are computed. The results show a significant effect of collision speed (p < 0.05) on all four metrics. The analysis has been further extended to study the effect of height and weight profile, bicycle mass, and impact directions on bicyclist-pedestrian collisions. According to the results, the impact directions largely influence the outcome of bicycle-pedestrian collisions. In general, direct impacts on pedestrian body center have been found to yield higher HIC values and probability of severe head injury to pedestrians than off-center impacts. Also, video analysis of simulated collisions has suggested that the accident mechanism depends on weight and height profiles (correlated with different age groups) and impact directions. Finally, recommendations have been proposed based on the study, including a speed limit of not more than 12 km/h for bicyclists on narrow shared paths and footpaths where risks of collisions with pedestrians are high. The results and analysis presented could be helpful for developing legislation to minimize conflicts between bicyclists and pedestrians on shared paths and to reduce potential injury to pedestrians.

Barriers and factors associated with the use of helmets by Motorcyclists: A scoping review

Road Traffic Injuries (RTIs) have imposed a great global burden on public health. Motorcyclists and pedestrians comprise the most significant proportion of this burden. Several studies have demonstrated a link between helmet wearing and a decline in the impact of RTIs in motorcyclists. In this study, we aimed to review the barriers to helmet utilization by motorcyclists. This scoping review has been conducted in accordance with the guidelines for the systematic review of observational studies and the PRISMA Checklist. The search was conducted by using related keywords in EMBASE, PubMed, Scopus, and Cochrane Library. Four independent reviewers carried out the screening. The main outcomes of interest were barriers to helmet usage among motorcyclists, drawn from the finally included studies. Fifty-three records were selected for data extraction. According to these reports, the barriers and factors associated with helmet usage among motorcyclists were categorized into five entities as: legislations/enforcement strategies, helmet disadvantages (discomfort, visual/auditory blockage, and thermal dysregulation), risky behaviors (riding while drunk or high on drugs), sex and/or age factors, and the location and time of the injury event (rural vs. urban locations, day vs. night riding). From the perspective of policymakers, the findings of this review are of utmost importance and could be used in addressing the challenge of inadequate compliance with helmet use.

A rubberized impact absorbing pavement can reduce the head injury risk in vulnerable road users: A bicycle and a pedestrian accident case study

OBJECTIVE

Vulnerable Road Users (VRU), including pedestrians and cyclists, are generally the least protected road users and are frequently missed in the planning process of preventive measures. Rubberized asphalt mixtures were originally developed as a possible environmentally friendly solution to recycle the End-of-Life Tires while making the pavements more durable. The objective of the current study was to explore the effects of increasing the rubber content of the common rubberized asphalt mixtures in reducing the head injuries risk for VRUs.

METHOD

To achieve this purpose, four different sample series with 0, 14, 28, and 33 weight percent rubber in each were tested. A compressive test without permanent deformation and one with failure were performed on each sample series. The mechanical behavior of each set was modeled using a MAT_SIMPLIFIED_RUBBER material model in LS-Dyna and validated against a standard Head Injury Criterion (HIC) drop test. Ultimately, previously low-speed accident reconstructed cases, a bicycle and a pedestrian one, were used to assess the effect of varying the rubber content on reducing the head injury risk.

RESULTS

In the bicycle accident case, the risk of skull fracture was reduced from 0.99 to 0.29 when comparing the non-rubberized asphalt mixture with the 33% rubber mixture. In the same accident case, the risk of concussion, evaluated using the logistic regression method, was reduced from 0.97 in the non-rubberized mixture to 0.81 in the 33% rubber mixture. The initial conditions, linear and rotational velocities, were lower for the pedestrian case compared to the bicycle case (the bicycle case was more severe compared to the pedestrian case), which led to lower strains in the pedestrian case. In the pedestrian accident case, the risk of skull fracture was reduced from 1.00 in the non-rubberized mixture to 0.63 in the 33% rubber mixture, while the risk of concussion was reduced from 0.64 to 0.07.

CONCLUSION

The rubberized asphalt mixtures could reduce the head injury risk for the studied cases when the rubber content in the asphalt mixture increases.

Skateboard head injuries: Are we making progress?

BACKGROUND

Skateboarding is a popular sport and U.S. trauma centers care for a significant number of skateboard-related injuries (SRIs). However, injury prevention strategies are still underdeveloped. This study was designed to compare the epidemiology, type, and location of skateboard injury as well as the use and influence of protective gear over two time periods.

METHODS

This is a retrospective National Trauma Data Bank study including all patients with SRIs between 2007and 2016. Study groups were divided into two 5-year periods: 2007-2011 and 2012-2016. The incidence and severity of traumatic brain injury (TBI), as well as the compliance and effectiveness of protective gear and skate parks, was assessed in various age groups in the two study periods using univariable and multivariable analyses. Univariable analysis was used to compare the two study periods, logistic regression analysis was performed to identify independent predictors of head injury and severe TBI.

RESULTS

24,903 patients presented with SRIs: 10,594 from 2007 to 2011 and 14,309 from 2012 to 2016. Helmet use was low in both periods (5.7% and 5.4% respectively). The incidence of severe TBI (head AIS≥3) did not change significantly during the two periods (31.6% vs. 30.8%, p = 0.162). In children with severe TBI, there was no significant difference in helmet use across all ages, (10.4% vs. 11.5%, p = 0.467; 6.4% vs. 6.5%, p = 0.753; 4.2% vs. 3.7%, p = 0.201, respectively) with the lowest usage in the older than 16 years age group. On logistic regression, male gender (OR 1.526, 95% CI 1.372-1.698, p<0.001) was associated with increased odds of severe TBI, while helmet use (OR 0.534, 95% CI 0.455-0.627, p<0.001) and injuries at skate parks (OR 0.584, 95% CI 0.541-0.630, p<0.001), near home (OR 0.465, 95% CI 0.418-0.518, p<0.001), and public buildings (OR 0.386, 95% CI 0.440-0.541, p<0.001) were associated with reduced odds of severe TBI.

CONCLUSIONS

Helmet use in patients with SRIs is low in all pediatric age groups. Helmet use and skate parks are protective against severe TBI. Older age children and male gender are at increased risk of severe TBI after skateboard-related injuries, and more targeted preventive education and legislation are needed.

The Protective Performance of Modern Motorcycle Helmets Under Oblique Impacts

Motorcyclists are at high risk of head injuries, including skull fractures, focal brain injuries, intracranial bleeding and diffuse brain injuries. New helmet technologies have been developed to mitigate head injuries in motorcycle collisions, but there is limited information on their performance under commonly occurring oblique impacts. We used an oblique impact method to assess the performance of seven modern motorcycle helmets at five impact locations. Four helmets were fitted with rotational management technologies: a low friction layer (MIPS), three-layer liner system (Flex) and dampers-connected liner system (ODS). Helmets were dropped onto a 45° anvil at 8 m/s at five locations. We determined peak translational and rotational accelerations (PTA and PRA), peak rotational velocity (PRV) and brain injury criteria (BrIC). In addition, we used a human head finite element model to predict strain distribution across the brain and in corpus callosum and sulci. We found that the impact location affected the injury metrics and brain strain, but this effect was not consistent. The rear impact produced lowest PTAs but highest PRAs. This impact produced highest strain in corpus callosum. The front impact produced the highest PRV and BrIC. The side impact produced the lowest PRV, BrIC and strain across the brain, sulci and corpus callosum. Among helmet technologies, MIPS reduced all injury metrics and brain strain compared with conventional helmets. Flex however was effective in reducing PRA only and ODS was not effective in reducing any injury metrics in comparison with conventional helmets. This study shows the importance of using different impact locations and injury metrics when assessing head protection effects of helmets. It also provides new data on the performance of modern motorcycle helmets. These results can help with improving helmet design and standard and rating test methods.

Incorporating neck biomechanics in helmet testing: Evaluation of commercially available WaveCel helmets

BACKGROUND

Cycling helmets often incorporate elements aimed to dissipate rotational energies, which is widely acknowledged to play a key role in concussion mechanics. In this study, we investigated the mechanics of an oblique helmet test protocol that induced helmet rotation while using it to evaluate the effectiveness of three helmet models: two standard expanded polystyrene helmets and a commercially-available helmet equipped with a liner designed to mitigate linear and rotational energies.

METHODS

Helmets equipped with WaveCel were tested against two expanded polystyrene helmet models through guided drops using a Hybrid III (HIII) head-and-neck surrogate. The three helmet models were tested across four impact conditions (n = 5) of different speeds and impact surface angles.

FINDINGS

Across all tests, a similar sequence of head motion was observed - first a flexion phase followed by an extension phase. The extension phase lacked evidence of biofidelity and was likely attributable to the energy stored in the neckform during the flexion phase; it was therefore neglected from analysis. Results showed WaveCel reduced the probability of AIS2 head injury across all tests (3 to 27% reductions in 4.8 m/s impacts; 36 to 37% reductions in 6.2 m/s impacts).

INTERPRETATION

The two-phased response of the HIII suggests that boundary condition selection can influence results and should thus be reported in studies using similar methods. While this protocol involved both axial and tangential impact components and were thus representative of real-world collisions, the efficacy of WaveCel should be further investigated through additional laboratory studies and tracking real-world cycling injury statistics.

Influence of a Passenger Position Seating on Recline Seat on a Head Injury during a Frontal Crash

Presently, most passive safety tests are performed with a precisely specified seat position and carefully seated ATD (anthropomorphic test device) dummies. Facing the development of autonomous vehicles, as well as the need for safety verification during crashes with various seat positions such research is even more urgently needed. Apart from the numerical environment, the existing testing equipment is not validated to perform such an investigation. For example, ATDs are not validated for nonstandard seatback positions, and the most accurate method of such research is volunteer tests. The study presented here was performed on a sled test rig utilizing a 50cc Hybrid III dummy according to a full factorial experiment. In addition, input factors were selected in order to verify a safe test condition for surrogate testing. The measured value was head acceleration, which was used for calculation of a head injury criterion. What was found was an optimal seat angle −117°—at which the head injury criteria had the lowest represented value. Moreover, preliminary body dynamics showed a danger of whiplash occurrence for occupants in a fully-reclined seat.

Computational prediction of head-ground impact kinematics in e-scooter falls

E-scooters are the fastest growing mode of micro-mobility with important environmental benefits. However, there are serious concerns about injuries caused by e-scooter accidents. Falls due to poor road surface conditions are a common cause of injury in e-scooter riders, and head injuries are one of the most common and concerning injuries in e-scooter falls. However, the head-ground impact biomechanics in e-scooter falls and its relationship with e-scooter speed and design, road surface conditions and wearing helmets remain poorly understood. To address some of these key questions, we predicted the head-ground impact force and velocity of e-scooter riders in different falls caused by potholes. We used multi-body dynamics approach to model a commercially available e-scooter and simulate 180 falls using human body models. We modelled different pothole sizes to test whether the pothole width and depth influences the onset of falls and head-ground impact velocity and force. We also tested whether the e-scooter travelling speed has an influence on the head-ground impact velocity and force. The simulations were carried out with three human body models to ensure that the results of the study are inclusive of a wide range of rider sizes. For our 10 in. diameter e-scooter wheels, we found a sudden increase in the occurrence of falls when the pothole depth was increased from 3 cm (no falls) to 6 cm (41 falls out of 60 cases). When the falls occurred, we found a head-ground impact force of 13.2 ± 3.4kN, which is larger than skull fracture thresholds. The head-ground impact speed was 6.3 ± 1.4 m/s, which is the same as the impact speed prescribed in bicycle helmet standards. All e-scooter falls resulted in oblique head impacts, with an impact angle of 65 ± 10° (measured from the ground). Decreasing the e-scooter speed reduced the head impact speed. For instance, reducing the e-scooter speed from 30 km/h to 20 km/h led to a 14% reduction in the mean impact speed and 12% reduction in the mean impact force, as predicted by the models. The models also showed that the median male riders were sustaining higher head-ground impact force and speed compared with the small female and large male riders. The findings of this study can assist authorities and e-scooter hiring companies to take more informed actions about road surface conditions and speed limits. These results can also help define representative impact test conditions for assessing the performance of helmets used by e-scooter riders in order to reduce head and brain injuries in e-scooter falls.

Evaluation of the head protection effectiveness of cyclist helmets using full-scale computational biomechanics modelling of cycling accidents

INTRODUCTION

Cycling is a popular choice for urban transportation. Helmets are important and the most popular means of head protection for cyclists. However, a debate about the effectiveness of helmets in protecting a cyclist's head from injury continues.

METHOD

We employed computational biomechanics methods to analyze the head protection effectiveness of nine off-the-shelf-helmets for two typical impact scenarios that occur in cycling accidents: cyclist's head impacting a kerb (kerb-impact) and cyclist skidding (skidding impact) on the road surface. We conducted drop tests for all nine analyzed helmets, and used the test data for validation of the corresponding helmet finite element (FE) models created in this study. The validated helmet models were then used in the full-scale computer simulations (FE analysis for the skull, brain and helmet, and multibody dynamics for the remaining segments of the cyclist's body) of the cycling accidents for cyclists wearing a helmet and without a helmet.

RESULTS

The results indicate that helmets can reduce both the peak linear acceleration of the cyclist head center of gravity (COG) and the risk of cyclist skull fracture. However, higher rotational acceleration of the head COG was predicted for cyclists wearing helmets. The results obtained using the injury criteria that rely on the brain deformations (maximum shear strain MPS and cumulative strain damage measure CSDM) suggest that helmets may offer protection in all the analyzed cyclist impact scenarios. However, the predicted level of protection varies for different helmets and impact scenarios with appreciable variations in the predictions obtained using different injury criteria. Reduction in the maximum principal strain (MPS_0.98) for helmeted cyclists was predicted for both impact scenarios. In contrast, wearing the helmet reduced the CSDM only for the skidding impact scenario. For the kerb-impact scenario, no clear influence of the helmet on the predicted CSDM was observed.

Helmets Protect Pediatric Bicyclists From Head Injury and Do Not Increase Risk of Cervical Spine Injury

OBJECTIVES

Only 21 states have mandatory helmet laws for pediatric bicyclists. This study sought to determine the incidence of helmeted riders among pediatric bicyclists involved in a collision and hypothesized the risk of a serious head and cervical spine injuries to be higher in nonhelmeted bicyclists (NHBs) compared with helmeted bicyclists (HBs).

METHODS

The Pediatric Trauma Quality Improvement Program (2014-2016) was queried for pediatric (age <16 years) bicyclists involved in a collision. Helmeted bicyclists were compared with NHBs. A serious injury was defined by an abbreviated injury scale grade of greater than 2.

RESULTS

From 3693 bicyclists, 3039 (82.3%) were NHBs. Compared with HBs, NHBs were more often Black (21.6% vs 3.8%, P < 0.001), Hispanic (17.5% vs 9.3%, P < 0.001), without insurance (4.6% vs 2.4%, P = 0.012), and had a higher rate of a serious head injury (24.6% vs 9.3%, P < 0.001). Both groups had similar rates of complications and mortality (P > 0.05). The associated risk of a serious head (odds ratio = 3.17, P < 0.001) and spine injury (odds ratio = 0.41, P = 0.012) were higher and lower respectively in NHBs. Associated risks for cervical spine fracture or cord injury were similar (P > 0.05).

CONCLUSIONS

Pediatric bicyclists involved in a collision infrequently wear helmets, and NHBs was associated with higher risks of serious head injury. However, the associated risk of serious spine injury among NHBs was lower. The associated risks for cervical spine fracture or cervical cord injuries were similar. Nonhelmeted bicyclists were more likely to lack insurance and to be Black or Hispanic. Targeted outreach programs may help decrease the risk of injury, especially in at-risk demographics.

Head Impact Exposure of a Youth Football Team over Eight Consecutive Seasons

PURPOSE

This study examined HIE of middle school football players over multiple seasons.

METHODS

Head impact exposure was evaluated in 103 football players (11-14 yr) who participated in a community-based youth tackle football program, up to 2 yr, with the same coaching staff over eight consecutive seasons (2012-2019). Head impact exposure was assessed using the Head Impact Telemetry System. Median of individual mean head impacts per session (HIPS) and median of individual 50th and 95th percentile head impact magnitudes were compared across seasons.

RESULTS

There were 33,519 head impacts measured throughout the study. Median HIPS for all sessions decreased every year, with a significant reduction from 2012 to 2019 (11.1 vs 2.3 HIPS; P < 0.05). Median game HIPS were significantly reduced in 2019 compared with 2012-14 (5.00 vs 16.30-17.75 HIPS; P < 0.05). Median practice HIPS were reduced by 81.3%, whereas median game HIPS were reduced by 69.3%. Median 50th and 95th percentile linear and rotational acceleration were lower in 2019 compared with some earlier years but remained unchanged during games.

CONCLUSIONS

Head impacts incurred by youth football players decreased substantially over eight seasons, with players in the final year sustaining approximately one fifth the HIPS as players experienced during the first year. The most prominent decline occurred in practices, although players also had much fewer head impacts in games. These results suggest that coaches' and/or players' behavior can be modified to greatly reduce the head impact burden in youth football.

Evaluation of Protective Properties of Commercially Available Medical Helmets: Are Medical Helmets Protective?

OBJECTIVES

The aims of the study were to evaluate and to compare protective properties of commercially available medical helmets for a set of standardized head injury risk measures.

METHODS

Eleven helmet types were evaluated to represent the variety of commercially available medical helmet designs and manufacturers. A test mannequin and sensor apparatus were used to simulate a backward-standing fall. The head/neck size, mass, and "standing" height of the mannequin (5'9″) were representative of a 50th percentile male. A triaxial array was placed at the head center of mass to position 3 linear accelerometers and 3 angular rate sensors. Data were collected for 5 single trials for each helmet, as well as 5 repeated trials. Five trials were also collected with no helmet scenarios. Three head injury risk measures were examined (linear acceleration, angular acceleration, and head injury criterion). Data were analyzed by clinical cutoff thresholds and continuous values.

RESULTS

Helmets varied in their performance across head injury risk measures. All helmets provided higher levels of protection compared with no helmet scenarios. No helmets were protective for subdural hematoma (measured by angular acceleration). All helmets lost protective properties with repeated falls. Results for skull fracture risk were inconsistent between linear acceleration and head injury criterion injury risk measures.

CONCLUSIONS

No helmets were protective across all head injury risk measures. Medical helmets may reduce some fall injury severity but may not prevent all types of head injury. All helmets exhibited worsening of protective properties with repeated falls. We recommend medical helmets be replaced after each fall incident where the helmet impacts another surface.

Effect of pedestrian physique differences on head injury prediction in car-to-pedestrian accidents using deep learning

OBJECTIVE

The aim of this study is to identify the effects of pedestrian physique differences on head injury prediction in car-to-pedestrian accidents via deep learning.

METHODS

A series of parametric studies was carried out using a family car finite element model and MADYMO pedestrian models (AM50, AF05, 6YO). The car model was developed and tuned by 11 impact tests. The initial gaits for the pedestrian models were obtained from volunteer experiments to reproduce 420 pre-crash reactions. Furthermore, by factoring the pedestrian models (3 types), pedestrian directions (2 each), impact positions (3 each), and car velocities (6 levels) with the pre-crash parameters, a total of 45,360 car-to-pedestrian impact simulations were performed. After the simulations, image datasets were created by labeling the pedestrian collision images with head injury criteria of 15 ms (HIC) and dividing the images into training and test data based on model type. Next, deep learning was conducted using the training dataset to obtain trained models. Finally, the effects of pedestrian physique differences on head injury predictions were investigated based on the accuracy of each trained model for test data.

RESULTS

The results indicate that the head impact area and the amount of pedestrian information in the image differ depending on the pedestrian models. In head injury prediction with deep learning, AF05 showed the highest prediction accuracy (93.25%), followed by AM50 (90.61%) and 6YO (88.29%). These results using deep learning show that pedestrian physique differences affect the head injury prediction accuracies by 2.32-4.96 points.

CONCLUSIONS

Based on the prediction results of the trained models that learned the relationships between the pedestrian collision images and HIC from simulations, we demonstrated the desirable performance of deep learning methods in head injury prediction for adult men, women with small physique, and children. Furthermore, our results confirmed the effect of pedestrian physique differences on the injury prediction accuracy.

Differences in outcomes of mandatory motorcycle helmet legislation by country income level: A systematic review and meta-analysis

BACKGROUND

The recent Lancet Commission on Legal Determinants of Global Health argues that governance can provide the framework for achieving sustainable development goals. Even though over 90% of fatal road traffic injuries occur in low- and middle-income countries (LMICs) primarily affecting motorcyclists, the utility of helmet laws outside of high-income settings has not been well characterized. We sought to evaluate the differences in outcomes of mandatory motorcycle helmet legislation and determine whether these varied across country income levels.

METHODS AND FINDINGS

A systematic review and meta-analysis were completed using the PRISMA checklist. A search for relevant articles was conducted using the PubMed, Embase, and Web of Science databases from January 1, 1990 to August 8, 2021. Studies were included if they evaluated helmet usage, mortality from motorcycle crash, or traumatic brain injury (TBI) incidence, with and without enactment of a mandatory helmet law as the intervention. The Newcastle-Ottawa Scale (NOS) was used to rate study quality and funnel plots, and Begg's and Egger's tests were used to assess for small study bias. Pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were stratified by high-income countries (HICs) versus LMICs using the random-effects model. Twenty-five articles were included in the final analysis encompassing a total study population of 31,949,418 people. There were 17 retrospective cohort studies, 2 prospective cohort studies, 1 case-control study, and 5 pre-post design studies. There were 16 studies from HICs and 9 from LMICs. The median NOS score was 6 with a range of 4 to 9. All studies demonstrated higher odds of helmet usage after implementation of helmet law; however, the results were statistically significantly greater in HICs (OR: 53.5; 95% CI: 28.4; 100.7) than in LMICs (OR: 4.82; 95% CI: 3.58; 6.49), p-value comparing both strata < 0.0001. There were significantly lower odds of motorcycle fatalities after enactment of helmet legislation (OR: 0.71; 95% CI: 0.61; 0.83) with no significant difference by income classification, p-value: 0.27. Odds of TBI were statistically significantly lower in HICs (OR: 0.61, 95% CI 0.54 to 0.69) than in LMICs (0.79, 95% CI 0.72 to 0.86) after enactment of law (p-value: 0.0001). Limitations of this study include variability in the methodologies and data sources in the studies included in the meta-analysis as well as the lack of available literature from the lowest income countries or from the African WHO region, in which helmet laws are least commonly present.

CONCLUSIONS

In this study, we observed that mandatory helmet laws had substantial public health benefits in all income contexts, but some outcomes were diminished in LMIC settings where additional measures such as public education and law enforcement might play critical roles.

Period of Purple Crying Program for the Prevention of Abusive Head Trauma/Shaken Baby Syndrome

The Period of PURPLE Crying Program is an educational program delivered to parents of newborn children that aims to reduce the incidence of abusive head trauma/shaken baby syndrome1. The program was developed by a research-based, non-profit organisation and has already been implemented in many countries around the world. It educates parents on what to expect during the first few months of their newborn infant's life, allowing parents to become more informed and better prepared to care for their child. The recent surge in the number of cases of abusive head trauma in children during the COVID-19 pandemic has highlighted the need for greater resources being made available to parents. The Period of PURPLE Crying Program is one such resource that could be implemented in Ireland.

A price-performance analysis of the protective capabilities of wholesale bicycle helmets

OBJECTIVE

Although bicycle helmets are an effective countermeasure against head injury, many cyclists do not wear one. One avenue for facilitating widespread helmet use is through community-driven helmet safety initiatives, which often give away or subsidize wholesale helmet models that are manufactured at a low price point. However, the impact performance of such helmets during real-world accident conditions has yet to be explored. The present study seeks to investigate trends between wholesale bicycle helmet price and protective capabilities.

METHODS

Nine common wholesale helmet models (price range $3.65-$12.95) were evaluated according to the bicycle Summation of Tests for the Analysis of Risk (STAR) methodology, which analyzes helmet performance in 24 oblique impact tests reflecting common cyclist head impact conditions. Resulting head peak linear acceleration (PLA) and peak rotational velocity (PRV) were collected and used to predict risk of concussion. Concussion risks were then combined using the STAR algorithm in order to summarize each model's risks into a single, weighted metric.

RESULTS

Large ranges in kinematic results led to large variations in concussion risks between helmets, and in turn, large variations in STAR values (13.5-26.2). Wholesale helmet price was not significantly associated with STAR, although incorporating 30 previous bicycle helmet STAR results produced a weak negative correlation between price and STAR overall. Nonetheless, the best-performing wholesale helmet produced one of the lowest overall STAR values for a price of $6.45. Helmet style was instead a superior predictor of STAR, with multi-sport style helmets producing significantly higher linear accelerations and resulting STAR values than bike style helmets.

CONCLUSIONS

These results show that the impact performance of wholesale helmets ranges considerably despite their low price-points. Results can also guide helmet safety promotion organizers toward distributing wholesale bicycle helmet models associated with lower overall concussion risks.

Autopsy assessment of pediatric head injury: a proposal for aerosol mitigation during the COVID-19 pandemic

During the Corona Virus Disease-19 (COVID-19) pandemic, there is still a requirement for post-mortems to continue, including those examinations performed in the context of medico-legal investigations. Currently, very little is known about how long this coronavirus can survive in deceased human bodies or whether un-embalmed human cadavers can be contagious to people who handle them. Therefore, it would appear to be prudent to consider implementation of additional safety measures for all necessary post-mortem procedures. During the post-mortem examination of babies and young children, it is important to open the calvarium to enable visualization of the brain and its coverings, particularly in cases where a head injury is likely to have occurred. Since October 2013, the use of neurosurgical equipment to open the calvarium during infant and young child autopsies has become routine practice in our unit. Both the neurosurgical craniotome and a standard oscillating mortuary saw produce particulate matter consisting of bone and body fluids (including blood) which can become aerosolized. Within this paper, we discuss the use of a transparent plastic tent whilst opening the calvarium during pediatric post-mortems, to reduce the spread of aerosols into the mortuary environment.

The effectiveness of different types of motorcycle helmets - A scoping review

BACKGROUND

Protective helmets may reduce the risk of death and head injury in motorcycle collisions. However, there remains a large gap in knowledge regarding the effectiveness of different types of helmets in preventing injuries.

OBJECTIVE

To explore and evaluate the effectiveness of different types of motorcycle helmets; that is the association between different helmet types and the incidence and severity of head, neck, and facial injuries among motorcyclists. Also, to explore the effect of different helmet types on riders.

METHODS

A systematic search of different scientific databases was conducted from 1965 to April 2019. A scoping review was performed on the included articles. Eligible articles were included regarding defined criteria. Study characteristics, helmet types, fixation status, retention system, the prevention of injury or reduction of its severity were extracted.

RESULTS

A total of 137 studies were included. There was very limited evidence for the better protection of full-face helmets from head and facial injury compared to open-face and half-coverage helmets. There was however scarce evidence for the superiority of a certain helmet type over others in terms of protection from neck injury. The retention system and the fixation status of helmets were two important factors affecting the risk of head and brain injury in motorcyclists. Helmets could also affect and limit the riders in terms of vision, hearing, and ventilation. Multiple solutions have been discussed to mitigate these effects.

CONCLUSION

Full-face helmets may protect head and face in motorcycle riders more than open-face and half-coverage helmets, but there is not enough evidence for better neck protection among these three helmet types. Helmets can affect the rider's vision, hearing, and ventilation. When designing a helmet, all of these factors should be taken into account.

Parental knowledge on infant crying and abusive head trauma and relevant shaking behaviors in China

BACKGROUND

This study aims to characterize the knowledge about infant crying and abusive head trauma (AHT), and shaking behaviors in parents of children in China, which are lacking currently.

METHODS

A cross-sectional survey was conducted in 2020. We collected information about the knowledge of the typical patterns of infant crying and AHT, and asked about beliefs of the effects of violent shaking on children's health, and shaking behavior among parents.

RESULTS

A total of 568 parents completed the questionnaire, and only 1.6 % of them answered all nine knowledge questions related to infant crying correctly. Overall, 42.6 % of participants reported they had heard about AHT, but only 17.1 % of the parents reported they knew enough about the dangers of infant shaking. About 45 % of the parents acknowledged that they had shaken their infants at least once. Parents who were from western region of China (OR = 3.860; 95 % CI = 1.871, 7.966; p < 0.001) and have felt very frustrated because of the baby's crying over half of the time (OR = 3.401; 95 % CI = 1.862, 6.211; p < 0.001) had the highest risk of shaking. Majority of the parents reported that they needed further information about infant soothing techniques, knowledge of prevention and treatment about AHT.

CONCLUSIONS

Majority of Chinese parents do not have enough knowledge about normal infant crying, nevertheless, most of them expressing needs in learning more. Community-wide advocating efforts aiming to educate parents on awareness and knowledge about AHT should be a health priority in China.

Potential of Soft-Shelled Rugby Headgear to Reduce Linear Impact Accelerations

The purpose of this study was to examine the potential of soft-shelled rugby headgear to reduce linear impact accelerations. A hybrid III head form instrumented with a 3-axis accelerometer was used to assess headgear performance on a drop test rig. Six headgear units were examined in this study: Canterbury Clothing Company (CCC) Ventilator, Kukri, 2nd Skull, N-Pro, and two Gamebreaker headgear units of different sizes (headgears 1-6, respectively). Drop heights were 238, 300, 610, and 912 mm with 5 orientations at each height (forehead, front boss, rear, rear boss, and side). Impact severity was quantified using peak linear acceleration (PLA) and head injury criterion (HIC). All headgear was tested in comparison to a no headgear condition (for all heights). Compared to the no headgear condition, all headgear significantly reduced PLA and HIC at 238 mm (16.2-45.3% PLA and 29.2-62.7% HIC reduction; P < 0.0005, η p 2 = 0.987-0.991). Headgear impact attenuation lowered significantly as the drop height increased (32.4-5.6% PLA and 50.9-11.7% HIC reduction at 912 mm). There were no significant differences in PLA or HIC reduction between headgear units 1-3. Post hoc testing indicated that headgear units 4-6 significantly outperformed headgear units 1-3 and additionally headgear units 5 and 6 significantly outperformed headgear 4 (P < 0.05). The lowest reduction PLA and HIC was for impacts rear orientation for headgear units 1-4 (3.3 ± 3.6%-11 ± 5.8%). In contrast, headgear units 5 and 6 significantly outperformed all other headgear in this orientation (P < 0.0005, η p 2 = 0.982-0.990). Side impacts showed the greatest reduction in PLA and HIC for all headgear. All headgear units tested demonstrated some degree of reduction in PLA and HIC from a linear impact; however, units 4-6 performed significantly better than headgear units 1-3.

Motorcycle helmet selection and usage for improved safety: A systematic review on the protective effects of helmet type and fastening

OBJECTIVE

Motorcycle helmets are the most common and effective protective device to reduce head injuries and mortality in crashes among powered two-wheeler riders. Even if they are globally recognized as effective, there are still concerns regarding their correct use, which is necessary to achieve maximum head protection. The goal of this systematic review is to assess which characteristics of helmet design and use showed a positive influence on rider safety, in order to provide insights to improve end-user helmet usage.

METHODS

A literature search was carried out combining two sets of keywords, one related with either motorcycle or rider and the other referring to either protective equipment or injuries. After the exclusion of duplicates, 977 papers were screened by reviewers, thus identifying 32 papers that were analyzed in group discussions.

RESULTS

Among the papers included in this study, no strong conflicting conclusions emerged in their results. The studies focusing on the use of different types of helmets highlighted that full-face helmets, compared with other standard helmets, have a positive influence on head injuries and facial injuries. Correct fastening was clearly beneficial for head and facial injuries, induced injuries, and helmet ejection.

CONCLUSIONS

This systematic review provides important insights to improve the usage of helmets by end-users. Correct fastening is a crucial factor to avoid helmet roll-off during a crash. Most studies agreed that full-face helmets provide higher protection in comparison with other standard helmets, especially for facial injuries, and no negative influence with respect to neck and spinal injuries.

Classification of road traffic injury collision characteristics using text mining analysis: Implications for road injury prevention

Road traffic injuries are a leading cause of morbidity and mortality globally. Understanding circumstances leading to road traffic injury is crucial to improve road safety, and implement countermeasures to reduce the incidence and severity of road trauma. We aimed to characterise crash characteristics of road traffic collisions in Victoria, Australia, and to examine the relationship between crash characteristics and fault attribution. Data were extracted from the Victorian State Trauma Registry for motor vehicle drivers, motorcyclists, pedal cyclists and pedestrians with a no-fault compensation claim, aged > = 16 years and injured 2010-2016. People with intentional injury, serious head injury, no compensation claim/missing injury event description or who died < = 12-months post-injury were excluded, resulting in a sample of 2,486. Text mining of the injury event using QDA Miner and Wordstat was used to classify crash circumstances for each road user group. Crashes in which no other was at fault included circumstances involving lost control or avoiding a hazard, mechanical failure or medical conditions. Collisions in which another was predominantly at fault occurred at intersections with another vehicle entering from an adjacent direction, and head-on collisions. Crashes with higher prevalence of unknown fault included multi-vehicle collisions, pedal cyclists injured in rear-end collisions, and pedestrians hit while crossing the road or navigating slow traffic areas. We discuss several methods to promote road safety and to reduce the incidence and severity of road traffic injuries. Our recommendations take into consideration the incidence and impact of road trauma for different types of road users, and include engineering and infrastructure controls through to interventions targeting or accommodating human behaviour.

Evaluation of Rotation Reduction Features in Infant and Extended-Use Convertible Child Restraint Systems during Frontal and Rear Impacts

A correctly used child restraint system (CRS) is associated with a substantial reduction of injury and mortality risks in motor vehicle crashes and epidemiologic data suggests that toddlers are provided greater protection when restrained in a rearward-facing CRS compared to a forward-facing CRS. Some 'extended-use' European CRS models can accommodate children up to six years rearward-facing and have a support (load) leg and/or a pair of lower (Swedish) tethers to reduce rotation during frontal and rear impacts, respectively. Laboratory studies have found that a support leg reduces head and neck injury metrics of anthropomorphic test devices (ATDs) younger than three years in rearward-facing CRS models during frontal impacts. The objectives of the current study were to perform sled tests to: (1) evaluate the effects of using a support leg in rearward-facing infant and extended-use convertible CRS models during frontal impacts, (2) evaluate the effects of using a pair of lower tethers in a rearward-facing extended-use convertible CRS model during rear impacts and (3) compare responses of ATDs in an extendeduse convertible CRS with a support leg and a pair of lower tethers in rearward- and forward-facing configurations during frontal and rear impacts. The presence of a support leg in rearward-facing infant and extended-use convertible CRS models in frontal impacts was associated with reductions in head injury metrics across a range of pediatric ATDs and neck injury metrics were below injury tolerance values. Other strategies in the design of rearward-facing CRS and front row vehicle seatbacks may be available to further reduce head injury metrics. Lower tethers reduced the rearward rotation of an extended-use convertible CRS toward the vehicle seatback in rear impacts and were typically associated with reductions in head and neck injury metrics for the Q6 ATD, but not the Q3 ATD. For frontal impacts, neck injury metrics were typically greater for ATDs in the forward-facing extended-use convertible CRS, whereas head injury metrics were typically greater for the rearward-facing condition (with a support leg and a pair of lower tethers). Interactions of the ATD head and/or the rearward-facing extended-use convertible CRS with the blocker plate in rearward-facing frontal impacts need to be further investigated.