The seat significantly contributes to driving safety. Ergonomic seats prevent physical strain and fatigue, so attention and concentration do not drop so quickly, which helps to avoid accidents. The article generally presents the development of seats used in cars and the current areas of use of rotatable seats. Furthermore, it gives an overview of the possible seating positions for fully autonomous vehicles. The article leads the reader through the crash test simulation focusing on the model used. Subsequently, the article presents the research results so far and the possibilities for further development of the driver\'s seat. The article highlights the change in the driver\'s movement kinematics as a crucial observation. This change significantly increases the risk of serious injury. In frontal collisions, the modified seat consistently demonstrates results below the specified limit. It is important to note that there are injury values that increase, but these are not a problem because they remain below the limit. In the case of a side collision, the aim was less to reduce injury values and more to better coordinate the kinematics of the passenger\'s movement during the accident. It can be concluded that this is achievable with the modified seat, as the passenger\'s movements are notably more predictable and coordinated under these circumstances.

Differences in injury risk between females and males are often reported in field data analysis. The aim of this study was to investigate the differences in kinematics and injury risks between average female and male anthropometry in two exemplary use cases. A simulation study comprising the newly introduced VIVA+ human body models (HBM) was performed for two use cases. The first use case relates to whiplash associated disorders sustained in rear impacts and the second to femur fractures in pedestrians impacted by passenger cars as field data indicates that females have higher injury risk compared to males in these scenarios. Detailed seat models and a generic vehicle exterior were used to simulate crash scenarios close to those currently tested in consumer information tests. In the evaluations with one of the vehicle seats and one car shape the injury risks were equal for both models. However, the risk of the average female HBM for whiplash associated disorders was 1.5 times higher compared to the average male HBM for the rear impacts in the other seat and 10 times higher for proximal femur fractures in the pedestrian impacts for one of the two evaluated vehicle shapes.. Further work is needed to fully understand trends observed in the field and to derive appropriate countermeasures, which can be performed with the open source tools introduced in the current study.

In the US, 27% of car occupant fatalities occur in side-impacts. Near-side impacts cause more serious injuries than far-side impacts. Car occupant safety overall has improved, but rear-seat occupant protection lags behind front-seat protection. The current study had two aims: first, to describe crash characteristics and injury outcomes for near-side rear-seated restrained occupants before and after side-impact regulations (FMVSS-214) were mandated; and secondly, to estimate injury risks in near-side impact depending on seating position, delta-v, and other predictors.
The National Automotive Sampling System - Crashworthiness Data System (NASS - CDS) database for 1995 to 2015 was analyzed. The descriptive statistics focused on rear-seated restrained adults, comparing old (<1997) and new (≥1997) vehicles exposed to near-side impacts. Weighted logistic regression models including all front and rear-seat occupants were used to predict the occurrence of at least moderate injury in near-side impacts.
Rear-seated restrained adults in new vehicles were exposed to higher delta-v and intrusion levels compared to old vehicles. Moreover, injuries to rear-seat occupants in new vehicles were more distributed across body regions, compared to old vehicles (mainly thorax and head). The risk of sustaining injuries increased significantly with delta-v and occupant age, when not using a seatbelt, when seated in a passenger car and when hit in the passenger compartment. The risk increased by trend, but not significantly, when seated in a newer vehicle, when seated in the rear-seat and when the crash opponent was an SUV or van.
Trends and risk factors for at least moderate injuries in near-side impacts were identified to guide future directions for occupant protection in side-impacts and its assessments.

OBJECTIVE: Pediatric restraint use has increased over time in the United States, but motor vehicle crashes remain a leading cause of death for children under age 18. Age-appropriate use of safety restraints (safety seats, booster seats, seat belt) and statewide child restraint laws can greatly reduce injury or death in the event of a crash. Surveillance of pediatric restraint use and compliance with policy can inform prevention efforts. This study aims to examine time trends in pediatric restraint use and compliance with pediatric passenger laws in Iowa by rurality and age.
METHODS: Fourteen years of Iowa observational pediatric restraint use data (2006-2019) are included in this cross-sectional study. Proportions of restrained youth by year, age, and rurality (rural, urban) were calculated. Log-linear models were used to compute the Annual Percent Change (APC) by year to explore trends in restraint use over time by rurality and by age group.
RESULTS: A total of 42,007 observed pediatric passengers with complete data from 2006 to 2019 were included in this study. Restraint use increased across all years and all age groups observed, with the largest increases among the older pediatric age groups. However, restraint use was consistently highest among the youngest child passengers. With all study years combined, the odds of being compliantly restrained were 13% lower in rural areas (OR = 0.87, 95% CI = 0.80, 0.95) compared to urban areas.
CONCLUSIONS: Restraint use was lower in rural areas and among older pediatric passengers, suggesting targeted efforts to increase restraint use among these groups may have the greatest impact on overall occupant protection.

The occupant\'s posture can be changeable to an inadvertent or unintentional out-of-seat position (OOSP) depend on their convenience. Understanding for OOSP has been demanded, but it is not sufficient; especially when AEB is activated. The aim of the current study was to characterize the motion responses of an occupant in various OOSPs when AEB is activated and to identify if there were any additional risks of injury or discomfort to the occupant. The normal seat position (NSP) and three OOSPs were defined to compare the difference of human responses, and six healthy males were participated. Particularly, the maximum rotation angles of the neck in OOSP2 and OOSP3 differed significantly around 1.3 ± 0.3 and 1.4 ± 0.2 times higher respectively than from in the NSP (p < 0.05). Occupants assuming OOSP3 exhibited motion characteristics were not restrained effectively and characterized a hovering and falling upper body and a slipping pelvis. This study has identified, for the first time, a potential risk of injury or discomfort when AEB is activated while an occupant is in an OOSP. This study may serve as fundamental data for the development of safety system that can improve restraint and counteract any deterioration in occupant safety.

To evaluate vehicle occupant injury risk, finite element human body models (HBMs) can be used in vehicle crash simulations. HBMs can predict tissue loading levels, and the risk for fracture can be estimated based on a tissue-based risk curve. A probabilistic framework utilizing an age-adjusted rib strain-based risk function was proposed in 2012. However, the risk function was based on tests from only twelve human subjects. Further, the age adjustment was based on previous literature postulating a 5.1% decrease in failure strain for femur bone material per decade of aging. The primary aim of this study was to develop a new strain-based rib fracture risk function using material test data spanning a wide range of ages. A second aim was to update the probabilistic framework with the new risk function and compare the probabilistic risk predictions from HBM simulations to both previous HBM probabilistic risk predictions and to approximate real-world rib fracture outcomes. Tensile test data of human rib cortical bone from 58 individuals spanning 17-99 years of ages was used. Survival analysis with accelerated failure time was used to model the failure strain and age-dependent decrease for the tissue-based risk function. Stochastic HBM simulations with varied impact conditions and restraint system settings were performed and probabilistic rib fracture risks were calculated. In the resulting fracture risk function, sex was not a significant covariate-but a stronger age-dependent decrease than previously assumed for human rib cortical bone was evident, corresponding to a 12% decrease in failure strain per decade of aging. The main effect of this difference is a lowered risk prediction for younger individuals than that predicted in previous risk functions. For the stochastic analysis, the previous risk curve overestimated the approximate real-world rib fracture risk for 30-year-old occupants; the new risk function reduces the overestimation. Moreover, the new function can be used as a direct replacement of the previous one within the 2012 probabilistic framework.

BACKGROUND: Active human body models (AHBM) consider musculoskeletal movement and joint stiffness via active muscle truss elements in the finite element (FE) codes in dynamic application. In the latest models, such as THUMS™ Version 5, nearly all human muscle groups are modeled in form of one-dimensional truss elements connecting each joint. While a lot of work has been done to improve the active and passive behavior of this 1D muscle system in the past, the volumetric muscle system of THUMS was modeled in a much more simplified way based on Post Mortem Human Subject (PMHS) test data. The stiffness changing effect of isometric contraction was hardly considered for the volumetric muscle system of whole human body models so far. While previous works considered this aspect for single muscles, the effect of a change in stiffness due to isometric contraction of volumetric muscles on the AHBM behavior and computation time is yet unknown.
METHODS: In this study, a simplified frontal impact using the THUMS Version 5 AM50 occupant model was simulated. Key parameters to regulate muscle tissue stiffness of solid elements in THUMS were identified for the material model MAT_SIMPLIFIED_FOAM and different stiffness states were predefined for the buttock and thigh.
RESULTS: During frontal crash, changes in muscle stiffness had an effect on the overall AHBM behavior including expected injury outcome. Changes in muscle stiffness for the thigh and pelvis, as well as for the entire human body model and for strain-rate-dependent stiffness definitions based on literature data had no significant effect on the computation time.
CONCLUSIONS: Kinematics, peak impact force and stiffness changes were in general compliance with the literature data. However, different experimental setups had to be considered for comparison, as this topic has not been fully investigated experimentally in automotive applications in the past. Therefore, this study has limitations regarding validation of the frontal impact results.
CONCLUSIONS: Variations of default THUMS material model parameters allow an efficient change in stiffness of volumetric muscles for whole AHBM applications. The computation time is unaffected by altering muscle stiffness using the method suggested in this work. Due to a lack of validation data, the results of this work can only be validated with certain limitations. In future works, the default material models of THUMS could be replaced with recently published models to achieve a possibly more biofidelic muscle behavior, which would even allow a functional dependency of the 1D and 3D muscle systems. However, the effect on calculation time and model stability of these models is yet unknown and should be considered in future studies for efficient AHBM applications.

Guardrails were designed to deter vehicle access to off-road areas and consequently prevent hitting rigid fixed objects alongside the road (e.g. trees, utility poles, traffic barriers, etc.). However, guardrails cause 10 % of deaths in vehicle-to-fixed-object crashes, which recently attracted attention in the highway safety community on the vehicle-based injury criteria used in regulations. The objectives of this study were to investigate both full-body and body-region driver injury probabilities using finite element (FE) simulations, to quantify the influence of pre-impact conditions on injury probabilities, and to analyze the relationship between the vehicle-based crash severity metrics currently used in regulations and the injury probabilities assessed using dummy-based injury criteria. A total of 20 FE impact simulations between a car (Toyota Yaris) with a Hybrid III M50 dummy model in the driver seat and an end terminal model (ET-Plus) were performed in various configurations (e.g. pre-impact velocities, offsets, and angles). The driver\'s risk of serious injuries (AIS 3+) was estimated based on kinematic and kinetic responses of the dummy during the crashes. A non-linear regression approach was used to compare the injury probabilities assessed in this study to the vehicle-based crash severity metrics used in the testing regulations. In particular, the US Manual for Assessing Safety Hardware (MASH) guideline and European procedures (EN1317) were used for the study. All the recorded dummy-based injury criteria values pass the Federal Motor Vehicle Safety Standard (FMVSS) 208 limits which indicated a low driver risk of serious injury. Overall, the pre-impact vehicle velocity showed to have the highest influence in almost all injury probabilities (59 %, 79 %, 62 %, and 44 % in full-body, head, neck, and chest injuries, respectively). The offset between vehicle midline and the guardrail barrier was the most important variable for thigh injuries (56 %). The assessed injury probabilities were compared to vehicle-based severity metrics. The full-body and chest injuries showed the highest correlation with Occupant Impact Velocity (OIV), Acceleration Severity Index (ASI), and Theoretical Head Impact Velocity (THIV) (R2 > 0.6). Lower correlations of thigh injuries were recorded to OIV (R2 = 0.59) and THIV (R2 = 0.46). Meanwhile, weak correlations were observed between all the other regressions which indicated that no vehicle-based criteria could be used to predict head and neck injuries. Car-to-end terminal crash FE simulations involving a dummy model were performed for the first time in this study. The results pointed out the limitations of the standard vehicle-based injury methods in terms of head and neck injury prediction. The dummy-based injury assessment methodology presented in this study could supplement the crash tests for various impact conditions. In addition, the models could be used to design new advanced guardrail end terminals.

There are two parts to the aim of this study. The first part comprised reviewing how men and women are represented in regulatory tests conducted to assess adult occupant safety in vehicles in Europe. This part also contains an overview of some differences between females and males that may influence dynamic responses in a crash. Based on the results of the review an outline for how to better represent the adult population in regulatory tests has been suggested. The second part was to reflect on these issues from a specific critical legal perspective, that is from a Gender Legal Studies point of view, focusing on the European legal framework that governs the tests of adult occupant safety in vehicles in Europe. Since the beginning of the 1970s legal scholars have shown in several areas of law that there is a gap between superior legislation and practice, but also between gender equality as a superior legal principle and subordinate legal rules that govern safety requirements. The same pattern can be discerned in the area of Transportation Law. The results of the review of the ECE regulations shows that the average sized male represents the adult population and that the average sized female has been excluded from regulations assessing the protection of adult vehicle occupants. The fundamental values, on which the Union is founded, including the overarching goals of the Union, seem to be rendered invisible in the laws and critically impact the safety of women in everyday life. According to the gender system theory, the interests and priorities of men are continuing to shape the law. Consequently, the law neglecting the safety of women on roads has implications on the development of society. The lack of legal provisions that demand female crash test dummies representing the female part of the population, means that there is no incentive for car manufacturers, authorities or other stakeholders to develop test methods and female crash test dummies in ways that promote political objectives expressed in legal form, i.e., the legal values expressed in general provisions and principles stated in the Treaty on European Union and the Treaty on the Functioning of the European Union, such as gender equality between women and men as well as non-discrimination This study highlights the undeniable gap between the legal framework and legal requirements with regard to occupant safety for the whole adult population. It would be attainable to bridge this particular gender gap by providing equal representation for the female part of the population with regard to vehicle safety, as that males benefit from.

Although rear-seating children in motor vehicles results in fewer injuries and fatalities in motor vehicle crashes, many children continue to be front-seated. This study seeks to identify parental barriers to rear-seating children in motor vehicles and strategies to increase child rear seat placement. Focus groups were conducted with parents of children 12 or younger to determine barriers to rear seating and strategies to increase child rear seat placement. Barriers to rear seat placement identified include the logistics of transporting multiple children with limited rear seat availability, the potential of children to harm themselves if rear-seated, and peer pressure. Parents felt there should be no option to sit elsewhere within the vehicle to help normalize rear-seating. Successful interventions to increase child rear seat placement should focus on parental barriers to rear-seat their children in vehicles, including normalizing rear seat placement, and determining approaches to make rear-seat placement with multiple children uncomplicated.