The purpose of this study was to assess severe abdominal injury in child passengers of different ages of motor vehicle accidents and analyze the concomitant pattern of injury regarding injury severity, trauma management and outcome. Data acquisition from Trauma Register DGU® (TR-DGU) in a 10-years period (2010–2020) of seriously injured children (max. AIS 2+ / intensive care) 0–15 years of age, as motor vehicle passengers (cMVP) (n = 1,035). Primarily treated in or transferred to a German Trauma Center. Matched pairs analysis with adult severely injured motor vehicle passengers (aMVP) (age 20–50 years, n = 26,218), matching 1:4 (child: adult), was performed to identify causes of mortality. The study group (cMVP) included 1,035 children. The mean age was 9.5 years, 50.5

Crash severity may vary across roads because crashes on the same road share contextual characteristics not fully represented by observed variables. This study examined road-level heterogeneity using 19,956 police-reported crashes from 100 rural two-lane highways in Iran during 2021-2024. Single-level logistic regression was compared with random-intercept and random-coefficient multilevel logistic models. A regression-based mixed-effects random forest (MERF) was also used for an exploratory assessment of nonlinear predictive relationships and road-level patterns. The null multilevel model produced an intraclass correlation coefficient of 20.3 percent, indicating meaningful latent between-road variation in crash severity. Pavement condition had the largest estimated random-slope variance, followed by lighting condition, driver education, and driver age. Logistic road-level random intercepts ranged from -2.87 to +1.51 on the log-odds scale. In a comparison excluding road-specific information, the ten-variable MERF random-forest component achieved an AUC of 0.701, compared with 0.638 for single-level logistic regression. Retaining MERF road-level corrections for roads represented during training increased AUC to 0.763. MERF road-level corrections were strongly associated with logistic random intercepts (Pearson r = 0.892; Spearman rho = 0.931), indicating similar relative road patterns, although the estimates are not numerically equivalent. The findings support complementary use of multilevel and nonlinear models. Road-level estimates may help prioritize further investigation, but they do not measure crash frequency, total road risk, or causal effects.

Objective: This study aims to make the comparison of the kinematics and possible injury values of the occupant in the highly reclined seating position in two cases: the first case is without the braking maneuver prior to the frontal crash, and the second case is considering the braking maneuver prior to the impact. Methods: This study used the MADYMO human body model 50th percentile mid-size male seated on the front passenger seat model with the seatback reclined rearward 53 degrees (fully reclined seatback) to simulate the occupant biomechanics and behavior during a frontal collision. To achieve the study aim, two simulation models were created. The first model is called the non-precrash model (VaAM-O). It was set to simulate the occupant kinematics in the fully reclined initial seating posture in the 200ms of a crash without the braking maneuver before the crash. The second model, called the precrash model (VaAM-I), identified the occupant's initial position after the car model performed a 1s deceleration of a braking maneuver. VaAM-I has then also simulated the occupant kinematics in 200ms of a crash. Results: This study showed a significant difference in the occupant's posture at the beginning of the crash phase in the two cases. The upper torso of VaAM-I rotated up and moved forward earlier than VaAM-O prior to the crash phase due to the influence of the braking maneuver, and at the 50 ms, when the airbag deployed completely, the head had no contact with the airbag, and the head in VaAM-I forwarded to the airbag closer than VaAM-O about 24% of the distance to the airbag. Conclusions: This study supplements the value data for the study of the out-of-position OOP of the occupant in the frontal crash. The contact force and position contact between the head and the airbag could attract the audience's attention. On the other hand, a comparison of the seatbelt force and the seatbelt contacts the body between the conventional seatbelt as in this study, and the seat-integrated seatbelt system in the case wherein the occupant seats on the front seat with a highly reclined seatback should be performed.

The purpose of this study was to evaluate whether prolonged re-boarding of restraint children in motor vehicle accidents is sufficient to prevent severe injury. Data acquisition was performed using the Trauma Register DGU® (TR-DGU) in the time period from 2010 to 2019 of seriously injured children (AIS 2 +) aged 0–5 years as motor vehicle passengers (MVP). Primarily treated and transferred patients where included. The study group included 727 of 2030 (35.8%) children, who were severely injured (AIS 2 +) in road traffic accidents, among them 268 (13.2%) as MVPs in the age groups: 0–1 years (42.5%), 2–3 years (26.1%) and 4–5 years (31.3%). The pattern of severe injury was head/brain (56.0%), thoracic (42.2%), abdominal (13.1%), fractures (extremities and pelvis, 52.6%) and spine/severe whiplash (19.8%). The 0–1-year-old MVPs showed the significantly highest proportion of brain injuries with Glasgow Coma Score (GCS) < 8 and severe injury to the spine. The 2–3-year-olds showed the significantly highest proportion of fractures especially the lower extremity and highest proportion of cervical spine injuries of all spine injuries, while the 4–5-year-olds, the significantly highest proportion of abdominal injury and second highest proportion of cervical spine injury of all spine injuries. MVPs of the 0–1-year-old and 2–3-year-old groups showed a higher median Injury Severity Score (ISS) of 21.5 and 22.1 points than the older children (17.0 points). They also suffered an AIS-6-injury significantly more often (9 of 21) of spine (p = 0.001). Especially the cervical spine was significantly more often involved. Passengers at the age of 0–1 years were treated with cardiopulmonary resuscitation (CPR) three times as often as older children in the prehospital setting and twice as often at admission in the Trauma Resuscitation Unit (TRU). Their survival rate was 7 out of 8 (0–1 years), 1 out of 6 (2–3 years) and 1 out of 4 (4–5 years). Although the younger MVPs are restraint in a re-boarding position, severe injury to the spine and head occurred more often, while older children as front-faced positioned MVPs suffered from significantly higher rates of abdominal and more often severe facial injury. Our data show, that it is more important to properly restrain children in their adequate car seats (i-size-Norm) and additionally consider the age-related physiological and anatomical specific risks of injury as well as co-factors in road traffic accidents, than only prolonging the re-boarding position over the age of 15 months as a single method.

Dummies are applied to validate the restraint system and indicate injury risk, but it is not sufficient for alternative postures, for example, the highly reclined seatback posture in a driverless function and a long journey. Computer simulation provides valuable information and might overcome the disadvantages of the physical dummy and simulate the occupant response better than the dummy in alternative postures. HBMs were used to investigate the occupant kinematics in a frontal crash with a highly reclined seatback, but the kinematics of the occupant in the pre-crash was not considered in such simulation models. The postures of the occupant prior to a crash impact the injury severity. It was assumed that the occupant seats on the front seat with the seatback reclining fully, and a braking maneuver is expected in about 0.5 to 1 s before an accident in the autonomous driving mode. At this moment, the occupant's posture is totally different from the initial time. The occupant kinematics in the successive crash should be calculated and derived from this point. This study addressed the occupant's posture and kinematics in the pre-crash in the case wherein the seatback reclined rearward partly or fully. The study used the MADYMO human body model to simulate the occupant posture and a dataset of the volunteer test to validate the model. It may be used sensitively to investigate the kinematics of the occupant posture in a frontal crash with the reclined seatback, and in some other studies of the occupant response during autonomous driving.