Assessing injury risks of reclined occupants in a frontal crash preceded by braking with varied seatbelt designs using the SAFER Human Body Model.

OBJECTIVE: This study investigated the effects of different seatbelt geometries and load-limiting levels on the kinematics and injury risks of a reclined occupant during a whole-sequence frontal crash scenario, using simulations with the Active SAFER Human Body Model (Active SHBM). METHODS: The Active SHBM was positioned in a reclined position (50°) on a semi-rigid seat model. A whole-sequence frontal crash scenario, an 11 m/s2 Automated Emergency Braking (AEB) phase followed by a frontal crash at 50 km/h, was simulated. The seatbelt geometry was varied using either a B-pillar-integrated (BPI) or Belt-in-seat (BIS) design. The shoulder belt load-limiting level of the BPI seatbelt was also varied to achieve either similar shoulder belt forces (BPI_Lower_LL) or comparable upper body displacements (BPI_Higher_LL) to the BIS seatbelt. Kinematics of different body regions and seatbelt forces were compared. The risks of sustaining a mild traumatic brain injury (mTBI), two or more fractured ribs (NFR2+), and lumbar spine vertebral fractures were also compared. RESULTS: During the pre-crash phase, head, first thoracic vertebra, and first lumbar vertebra displacements were greater with the BPI seatbelt than with the BIS, mainly due to the lack of initial contact between the torso and the seatbelt. Pelvis pre-crash displacements, however, remained consistent across seatbelt types. In the in-crash phase, variations in shoulder belt forces were directly influenced by the different load-limiting levels of the shoulder belt. The mTBI (around 20%) and NFR2+ (around 70-100%) risks were amplified with BPI seatbelts, especially at higher load-limiting force. However, the BPI design demonstrated reduced lumbar spine fracture risks (from 30% to 1%). CONCLUSIONS: The BIS seatbelt appears promising, as seen with the reduced mTBI and NFR2+ risks, for ensuring the protection of reclined occupants in frontal crashes. However, additional solutions, such as lap belt load limiting, should be considered to reduce lumbar spine loading.

The influence of seated postures and anthropometry on lap belt fit in vehicle occupants: A 3D computed tomography study.

OBJECTIVE: In vehicle frontal collisions, it is crucial that the lap belt is designed to engage with the anterior superior iliac spine (ASIS) of occupants for a reliable restraint. This study aims to understand the influence of different seated postures on the geometrical relationship of the seat belt and the pelvis for various occupants using 3D upright and supine computed tomography (CT) systems. METHODS: The 3D shapes of bones and soft tissues around the pelvis were acquired through a CT scan for 30 participants. They were seated in a rigid seat equipped with a lap belt simulating the front seat of a small car, and wore a lap belt in three seated postures: upright, slouched and reclined. Parameters related to the likelihood of submarining occurrences, such as belt-ASIS overlap (an index for assessing the potential engagement of the lap belt with the ASIS) and the belt-pelvis angle (the difference between the belt angle and the normal direction of the anterior edge of the ilium) were compared. RESULTS: It was observed that the pelvis angle tilted rearward as the hip point was positioned forward and seatback angle increased. This can be seen in the slouched and reclined posture. The belt-pelvis angle was comparable between the slouched and the reclined postures, and was closer to zero (indicating that the lap belt path is closer to perpendicular to the anterior edge of the ilium) compared to the upright posture. In contrast, the belt-ASIS overlap increased with an increasing flesh margin of the ASIS and shallower belt angle. This suggests that the belt-pelvis angle is influenced by the seated posture whereas the belt-ASIS overlap is dependent more on an individual's anthropometry. The plot of belt-pelvis angle and belt-ASIS overlap exhibited significant variability among participants. CONCLUSIONS: The belt-pelvis angle and the belt-ASIS overlap of individuals will provide valuable information for understanding the current belt-fit location and predicting submarining occurrences for individuals in various postures when designing restraint systems.

Investigating the severity of single-vehicle truck crashes under different crash types using mixed logit models.

INTRODUCTION: Almost 90% of fatal road crashes occur in developing countries. Among these countries, Iran has a noticeable fatal crash rate of 21.47 deaths per 100,000 persons. Improving the safety of trucks is of particular importance in Iran where road freight is used to transport almost 90% of the commodities. Researchers have suggested dichotomizing crashes into single- and multi-vehicle categories and found that when this is performed vast differences can be identified between the mechanisms behind these categories of crashes, particularly when investigating truck crashes. METHOD: This study investigated single-vehicle truck crashes in Khorasan Razavi province in Iran from 2013 to 2021. Likelihood ratio tests were employed to show that separate models are statistically valid for different crash types. Subsequently, three mixed logit crash-type models were developed to investigate 5,703 single-vehicle truck crashes. RESULTS: Four significant variables were exclusive to collisions with an object (brake failure, ABS, primary roads, and rainy or snowy weather), five significant variables were associated with run-off-road crashes (driving a loaded truck, speed limit (>60 km/h), paved shoulders, driving uphill, and inability to control the truck), and three significant variables were associated with overturn crashes (overloaded truck, curved roads, and changing direction suddenly). In all crash types, both fastening the seatbelt and speeding were found to be significant factors. CONCLUSION: The research highlights the need to analyze single-vehicle truck crashes using distinct crash type models and highlights the unique contributing factors of three common single-vehicle crash types. PRACTICAL APPLICATIONS: The study presents recommendations for policy to address key crash risks for trucks in Iran, including education and training to improve driver experience, compliance with seat belt usage, enforcement of speeding, and vehicle technologies to monitor drivers.

Ocular injuries associated with motor vehicle accidents: long term effects on quality of life.

PURPOSE: To describe the prevalence and outcome of motor vehicle accidents-associated ocular injuries. METHODS: A survey of patients who presented to the emergency room at a level 1 trauma center with motor vehicle accidents-associated ocular injuries. A patient questionnaire and review of clinical notes were conducted for all patients. RESULTS: Of 274 motor vehicle accident victims with ocular injuries who presented to the emergency room, 40 (15%) responded to the survey. Over half of them were driving a vehicle, and most reported wearing a seat belt or a helmet. Most ocular injuries were mild. The most common injuries were bone fractures, subconjunctival hemorrhage, eyelid involvement and corneal injury. Most respondents had no change in vision and perceived their ocular involvement as a minor part of their injury. Most respondents returned to work and to driving within a year. CONCLUSION: Our study sheds light on the details and extent of ocular involvement and the visual ability to perform daily activities following motor vehicle accidents.

Frontal NCAP crash tests with rear-seat occupant.

OBJECTIVES: The initial frontal NCAP tests in 1979 included lap-shoulder belted driver and right-front passenger and lap belted 6-year-old (yo) in the rear. The 35 mph barrier tests were reviewed and analyzed for the restraint performance of the front occupants and child in the rear. METHODS: The initial 100 crash tests (#1-#100) in the NHTSA database were searched for frontal barrier impacts. Fifteen tests met the criteria. There were three tests with the 1980 Chevrolet Citation at 35, 40 and 48 mph. There were 12 other tests with different passenger vehicles at 35 mph into the rigid barrier. The tests included a lap-shoulder belted Hybrid II (Part 572) dummy in the driver and right-front passenger seat and a lap belted 6 yo child dummy (Alderson VIP 6 C) in the center or right rear seat. Vehicle dynamics and occupant kinematics were analyzed, and dummy responses were compared. RESULTS: Vehicle deformation was progressive with impact speed for the Citation tests, leading NHTSA to settle on a 35 mph NCAP speed. The thirteen 35 mph NCAP tests had an average driver HIC of 1099 ± 381 (95th CI 207) and 3 ms chest acceleration of 55.7 ± 16.1 g (95th CI 8.8) with 7 of 13 vehicles failing FMVSS 208 injury criteria. The average right-front passenger HIC was 1179 ± 555 (95th CI 302) and 3 ms chest acceleration was 47.2 ± 14.6 g (95th CI 7.9) with 7 of 13 failing injury criteria. Only four tests (30.8%) passed driver and right-front passenger injury criteria.The responses in the rear seat were significantly worse. The average HIC was 2711 ± 1111 (95th CI 604) and 3 ms chest acceleration was 62.8 ± 10.6 g (95th CI 5.8). The films showed the child's upper body moved forward and rotated downward around the lap belt resulting in severe head impacts on the front seatback, floor, dummy legs or interior. All vehicles failed injury criteria by large margins. Submarining the lap belt was noted in 6 tests. HIC for the rear child was 2.47-times greater than the driver (t = 4.72, p < 0.001) and 2.30-times greater than the right-front passenger (t = 3.64, p < 0.005). CONCLUSIONS: In the 1979 NCAP tests, the child dummy experienced inadequate restraint by the lap belt in the rear seat. The child jackknifed around the lap belt, often submarined, with a severe head impact. No publication of the results has been found. NHTSA did not advise the public of the extremely poor restraint performance, even during the public discussions on the 1986 NTSB recommendation that U.S. vehicle manufacturers install lap-shoulder belts in rear outboard seats. None of the subsequent NCAP tests included a child or adult in the rear until nearly 25 years later.

History of airbag safety benefits and risks.

OBJECTIVE: The history of airbags was reviewed for benefits and risks as they became a supplement to lap-shoulder belts. Sled and crash tests were evaluated and field data was analyzed for airbag effectiveness. Field data on airbag deaths and studies on mechanisms of deployment injury were analyzed. The history was reviewed as airbags evolved from the early 1970s to today. METHODS: Airbag benefits were determined from NHTSA crash tests with unbelted and belted dummies in 40, 48, and 56 km/h (25, 30, and 35 mph) frontal impacts with and without airbags. The literature was reviewed for testing of passive restraints with and without airbags. Recent NCAP tests were compared with earlier tests to determine the change in occupant responses with seatbelts and supplemental airbags in modern vehicles. 1994-2015 NASS-CDS field data was analyzed for MAIS 4 + F injury. Risks were compared for belted and unbelted occupants in frontal impacts by delta V. Airbag risks were identified from field deployments and research. The 1973-76 GM fleet had two deaths due to the occupant being out-of-position (OOP). The mechanisms of injury were determined. From 1989-2003, NHTSA investigated 93 driver, 184 child passenger, and 13 adult passenger airbag deaths. The data was reviewed for injury mechanisms. Second generation airbags essentially eliminated OOP airbag deaths. More recently, three suppliers were linked to airbag rupture deaths. The circumstances for ruptures were reviewed. RESULTS: The risk for serious head injury was 5.495% in drivers and 4.435% passengers in 40-48 km/h (25-30 mph) frontal crash tests without belts or airbags. It was 80.5% lower at 1.073% in drivers and 82.0% at 0.797% in passengers with belts and airbags in 35 mph NCAP crash tests of 2012-20 MY vehicles. NASS-CDS field data showed a 15.45% risk for severe injury (MAIS 4 + F) to unbelted occupants and 4.68% with belted occupants in 30-35 mph frontal crash delta V with airbags, as deployed. The reduction in risk was 69.7% with belt use and airbags deploying in 96.1% of crashes. There were benefits over the range of delta V. Two airbag deaths were studied from the 1970s GM fleet of airbags. The unbelted driver death was caused by punchout force with the airbag cover blocked by the occupant and membrane forces as the airbag wrapped around the head, neck or chest with the occupant close to the inflating airbag. The unbelted child death was from airbag inflation forces from pre-impact braking causing the child to slide forward into the deploying airbag. Research showed that unrestrained children may have 13 different positions near the passenger airbag at deployment. NHTSA investigation of first generation airbag deaths found most driver deaths were females (75.3%) sitting forward on the seat track, close to the driver airbag. Seatbelt use was only 30%. Most child deaths (138, 75.4%) involved no or improper use of the lap-shoulder belts. Of these, 115 deaths involved pre-impact braking. Only 37 (20.2%) children were in child seats with 29 in rear-facing and 8 in forward-facing child seats. Eight child deaths (4.4%) occurred with lap-shoulder belt use. Airbag designs changed. More recently, Takata airbags were related to at least 24 deaths by airbag rupture prompting a recall; the successor company Joyson had an airbag recall. ARC airbags have experienced a chunk of the inflator propelled into the driver during deployment with several deaths leading to a recall. CONCLUSIONS: Airbags are effective in preventing death and injury in crashes. They provide the greatest protection in combination with seatbelt use. NHTSA estimated airbags saved 28,244 lives through 1-1-09 while causing at least 320 deployment deaths, which has prompted improved designs, testing, and recalls.

Frontal NCAP performance and field injury over 40 years.

OBJECTIVES: Vehicle and occupant responses in 35 mph NCAP tests were determined for small-midsize passenger cars grouped around model year (MY) 1980, 1990, 2000, 2010 and 2020. A baseline was established with 1980 vehicles not designed for NCAP. The results of four decades of vehicles designed for NCAP were compared to the baseline. The study also determined the risk for serious injury (MAIS 3 + F) by vehicle model year (MY) using 1989-2015 NASS and 2017-2020 CISS. It explored safety trends in frontal crashes over 50 MYs of vehicles. METHODS: The 1980 baseline group was established with 10 1979-1983 MY passenger cars weighing <1,500 kg. Four decades of vehicle crash tests from five manufacturers established trends in vehicle dynamics and dummy responses over four decades of vehicles designed for NCAP. Triaxial acceleration of the head and chest were reanalyzed for each test to have a consistent set of responses over five decades. The risk for serious injury (MAIS 3 + F) to the driver and front passenger was determined by vehicle MY using 1989-2015 NASS and 2017-2020 CISS with belted and unbelted drivers and right-front passengers. The data was sorted in four MY groups 1961-1989 MY, 1990-1999 MY, 2000-2009 MY and 2010 MY-2021 MY. The risk for MAIS 3 + F injury was determined with standard errors using weighted data. RESULTS: The 1980 NCAP tests brought about changes in vehicle structures and occupant restraints by 1990; however, HIC15 and 3 ms chest acceleration have not changed much the past 20 years since the use of advanced airbags and seatbelts with pretensioner and load-limiters. For the driver, HIC15 dropped 40 ± 19% from the 1980 to 1990 NCAP tests and dropped further to 76 ± 32% in 2020. The percentage drops after 1990 were not statistically significant. The driver 3 ms chest acceleration dropped 18 ± 5% from 1980 to 1990 and plateaued with 22 ± 6% in 2020. For the front passenger, HIC15 dropped 68 ± 52% from the 1980 to 1990 NCAP tests and plateaued at 71 ± 49% in 2020. The passenger 3 ms chest acceleration dropped 13 ± 5% from 1980 to 1990 and has fluctuated with minimal change. Injury risks based on responses show the same initial drop in 1990 and have remained essentially constant. Nothing meaningful has changed in dummy responses in the past 20 years of NCAP testing. The field data found the belted driver MAIS 3 + F risk was 1.66 ± 0.37% in 1961-1989 MY vehicles and 1.39 ± 0.33% in 2010-2021 MY vehicles. For belted right-front passengers, the risk was 1.52 ± 0.39% in 1961-1989 MY vehicles and 1.42 ± 0.46% in 2010-2021 MY vehicles. The field data shows no meaningful change in injury risk in 50 MYs of vehicles. NCAP involves 35-40 mph delta-V, which represents a small fraction, 0.33%, of belted occupant exposure and only 8.6% of severe injury based on 1994-2015 NASS. CONCLUSIONS: The NCAP test lacks field relevance. Manufacturers are merely "tuning" the restraint systems for star ratings without meaningful changes in field injury risks the past 20 years. There are disbenefits of "tuning" safety for a single, high-severity crash when most of the severe injury occurs in lower severity crashes. NHTSA should reevaluate plans to change the dummy to Thor and add BrIC injury criteria to assess NCAP responses. These changes would cause manufacturers to further "tune" structures, restraints and interiors without meaningful effects in real-world crashes.

Surveillance methods and interventions implemented in American Indian and Alaska Native communities to increase child restraint device and seat belt use in motor vehicles: a systematic review.

BACKGROUND: American Indian/Alaska Native (AI/AN) children are disproportionately affected by injuries and deaths related to motor vehicle crashes. We aimed to synthesise published evidence on surveillance methods and interventions implemented in AI/AN communities and analyse characteristics that make them successful in increasing child restraint devices and seat belt use. METHODS: Studies were collected from the PubMed, Scopus, and TRID databases and the CDC Tribal Road Safety website, Community Guide, and Indian Health Service registers. Included studies collected primary data on AI/AN children (0-17) and reported morbidity/mortality outcomes related to child restraint devices or seat belt use. Studies with poor methodological quality, published before 2002, whose data were collected outside of the USA, or were non-English, were excluded. Checklists from the Joanna Briggs Institute were used to assess the risk of bias. In the synthesis of results, studies were grouped by whether a surveillance method or intervention was employed. RESULTS: The final review included 9 studies covering 72 381 participants. Studies conducted surveillance methods, interventions involving law enforcement only and multipronged interventions. Multipronged approaches were most effective by using the distribution of child restraint devices combined with at least some of the following components: educational programmes, media campaigns, enactment/enforcement of child passenger restraint laws, incentive programmes and surveillance. DISCUSSION: Although this review was limited by the number and quality of included studies, available resources suggest that we need multipronged, culturally tailored and sustainable interventions fostered by mutually beneficial and trusting partnerships. Continued investment in AI/AN road safety initiatives is necessary.

Female vs. male relative fatality risk in fatal motor vehicle crashes in the US, 1975-2020.

Motor vehicle accidents are the leading cause of death for young adults 18-29 years old worldwide, resulting in nearly 1 million years of life lost annually in the United States. Despite improvements in vehicle safety technologies, young women are at higher risk of dying in car crashes compared with men in matched scenarios. Vehicle crash testing primarily revolves around test dummies representative of the 50th percentile adult male, potentially resulting in these differences in fatality risk for female occupants compared to males. Vehicle occupants involved in fatal car crashes were matched using seating location, vehicle type, airbag deployment, seatbelt usage, and age. The relative risk for fatality (R) between males and females was calculated using a Double Pair Comparison. Young women (20s-40s) are at approximately 20% higher risk of dying in car crashes compared with men of the same age in matched scenarios. In passenger cars, 25-year-old female occupants in passenger car crashes from 1975-2020 exhibit R = 1.201 (95% CI 1.160-1.250) compared to 25-year-old males, and R-1.117 (95% CI 1.040-1.207) for passenger car crashes from 2010-2020. This trend persists across vehicle type, airbag deployment, seatbelt use, and number of vehicles involved in a crash. Known sex-based differences do not explain this large risk differential, suggesting a need for expanded test methodologies and research strategies to address as-yet unexplored sex differences in crash fatalities. These differences should be further investigated to ensure equitable crash protection.

Education, incentive, and engineering-based interventions to promote the use of seat belts.

BACKGROUND: Over 1.3 million people die each year as a result of traffic collisions and hundreds of thousands of others are permanently and seriously injured. Most of these deaths occur in low- and middle-income countries, where mortality rates can be up to 10 times higher than those of some high-income countries. Seat belts are designed to accomplish two key functions - to prevent the occupant from being ejected from the vehicle by the force of impact, and to extend the time that the decelerating force is applied to a person. Seat belts also spread the area of impact both to larger and less vulnerable parts of the body. Since the 1950s, seat belts have been factory-fitted to most vehicles, and today around 90% of high-income countries have adopted seat belt legislation that makes it mandatory for some, if not all, vehicle occupants to wear seat belts. However, the simple passing of laws is not sufficient to ensure seat belt use, and, while the enforcement of seat belt laws does increase seat belt use, other interventions have been developed to encourage voluntary - and hence sustainable - behaviour change. OBJECTIVES: To evaluate the benefits of behavioural-change interventions (educational-based, incentive-based, engineering-based, or a combination, but not enforcement-based) that promote the use of seat belts, and to determine which types of interventions are most effective. SEARCH METHODS: On 9 August 2022, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), OvidSP Embase, OvidSP MEDLINE, 14 other databases, and clinical trials registers. We also screened reference lists and conference proceedings, searched websites of relevant organisations, and contacted road safety experts. The search was performed with no restrictions in terms of language and date of publication. SELECTION CRITERIA: We included randomised controlled trials (RCTs), both individually randomised and cluster-randomised, that evaluated education, engineering, incentive-based interventions (or combinations) that promoted seat belt use. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the eligibility of RCTs, evaluated the risk of bias, and extracted data. We performed a narrative synthesis based on effect direction due to the heterogeneity observed between RCTs and reported the synthesis in accordance with reporting guidelines for systematic reviews without meta-analysis, as appropriate. We assessed the certainty of the evidence using the GRADE approach. We analysed data on the primary outcome, frequency of wearing a seat belt. None of the included RCTs reported the other primary outcome, crash-related injury rate or the secondary outcome, crash-related mortality rates of interest in this review. MAIN RESULTS: We included 15 completed RCTs (12 individual, parallel-group, and three cluster) that enroled 12,081 participants, published between 1990 and 2022. Four trials were published between 2019 and 2022, and the remaining trials were published 10 or more years ago. We also identified four ongoing RCTs. Thirteen RCTs were conducted in the USA. Trials recruited participants from various sites (worksites, schools, emergency departments, a residential retirement community, and primary care settings) and different age groups (adults, late adolescents, early adolescents, and dyads). Thirteen trials investigated educational interventions, one of which used education in addition to incentives (one of the intervention arms) measured through participant self-reports (12) and observation (one), and two trials investigated engineering-based interventions measured through in-vehicle data monitor systems at various follow-up periods (six weeks to 36 months). We grouped RCTs according to types of education-based interventions: behavioural education-based, health risk appraisal (HRA), and other education-based interventions. The evidence suggests that behavioural education-based (four trials) interventions may promote seat belt use and HRA interventions (one trial) likely promote seat belt use in the short term (six weeks to nine months). Four of the six trials that investigated behavioural education-based interventions found that the intervention compared to no or another intervention may promote seat belt use. These effects were measured through participant self-report and at various time points (six-week to 12-month follow-up) (low-certainty evidence). One of the three trials investigating HRA only or with additional intervention versus no or another intervention showed observed effects likely to promote seat belt use (moderate-certainty evidence). The evidence suggests that engineering-based interventions using vehicle monitoring systems (with in-vehicle alerts and with or without notifications/feedback) may promote the use of seat belts. One trial showed that engineering interventions (in-vehicle alerts and feedback) may promote seat belt use while the other showed unclear effects in two of the three intervention groups (low-certainty evidence). Both trials had small sample sizes and high baseline seat belt use. AUTHORS' CONCLUSIONS: The evidence suggests that behavioural education-based interventions may promote seat belt use and HRA (including incentives) with or without additional interventions likely promote seat belt use. Likewise, for engineering-based interventions using in-vehicle data monitor systems with in-vehicle alerts, with or without notifications/feedback the evidence suggests the interventions may promote the use of seat belts. Well-designed RCTs are needed to further investigate the effectiveness of education and engineering-based interventions. High-quality trials that examine the potential benefits of incentives to promote seat belt use, either alone or in combination with other interventions, as well as trials to investigate other types of interventions (such as technology, media/publicity, enforcement, insurance schemes, employer programmes, etc.) to promote the use of seat belts, are needed. Evidence from low- and middle-income economies is required to improve the generalisability of the data. In addition, research focused on determining which interventions or types of interventions are most effective in different population groups is needed.

The Influence of a Booster Seat on the Motion of the Reclined Small Female Anthropomorphic Test Device in Low-Acceleration Far-Side Lateral Oblique Impacts.

Belt-positioning booster (BPB) seats may prevent submarining in reclined child occupants in frontal impacts. BPB-seated child volunteers showed reduced lateral displacement in reclined seating in low-acceleration lateral-oblique impacts. As submarining was particularly evident in reclined small adult female occupants, we examined if a booster seat could provide similar effects on the kinematics of the small female occupant to the ones found on the reclined child volunteers in low-acceleration far-side lateral oblique impacts. The THOR-AV-5F was seated on a vehicle seat on a sled simulating a far-side lateral-oblique impact (80 deg from frontal, maximum acceleration ∼2 g, duration ∼170 ms). Lateral and forward head and trunk displacements, trunk rotation, knee-head distance, seatbelt loads, and head acceleration were recorded. Three seatback angles (25 deg, 45 deg, 60 deg) and two booster conditions were examined. Lateral peak head and trunk displacements decreased in more severe reclined seatback angles (25-36 mm decrease compared to nominal). Forward peak head, trunk displacements, and knee-head distance were greater with the seatback reclined and no BPB. Knee-head distance increased in the severe reclined angle also with the booster seat (>40 mm compared to nominal). Seat belt peak loads increased with increased recline angle with the booster, but not without the booster seat. Booster-like solutions may be beneficial for reclined small female adult occupants to reduce head and trunk displacements in far-side lateral-oblique impacts, and knee-head distance and motion variability in severe reclined seatback angles.

Are crash causation studies the best way to understand system failures - Who can we blame?

The search for common and serious single causes of road crashes naturally leads to a concentration on the road user. This is supported by a legal framework in the search for the main cause and the suspect for this cause. In prevention, we havefor decades been more inclined to look for systematic improvements of all elements of the road transport system, and we direct the recommendations for actions towards system designers, organizations, products and services. In this paper the discussion about causation and prevention is broadened in the light of Vision Zero and its approach to prevention of serious and fatal injuries. We also discuss the Swedish judicial system and why the prevention approach has not been legislated or even generally accepted. Occupational health and safety legislation and road rules are compared, as well as how sustainability practices and reporting are tools to apply prevention where organizations have a natural sphere of influence that could mitigate deaths and serious injuries within value chains. It is recommended that we stop using the term causation as it is only directing actions in one direction. There is a risk that the focus on causation, in particular single causes, will deviate actions away from robust prevention countermeasures such as increased seat belt use, relevant speed limits, and well functioning roundabouts and median barriers. Furthermore, there is also a risk that important preventative actions from organizations are overlooked.

Predictive modeling of submarining risk in car occupants based on pelvis angle and lap belt positioning.

OBJECTIVE: The engagement of the lap belt with the pelvis is critical for occupant safety during vehicle frontal crashes to prevent occupant submarining. This study aims to develop a predictive model for submarining risk based on anthropometric parameters and lap belt positioning using finite element (FE) analyses. METHODS: FE analyses were conducted using human body models representing various body shapes (a 50th percentile male, low and high BMI males, and a 5th percentile female) in three seated postures (standard, reclined, and slouched). The lap belt-ASIS overlap and the belt-pelvis angle were used as key parameters for predicting submarining risk. A logistic regression analysis was utilized to correlate submarining occurrence with the initial values of these two parameters at the beginning of impact. Subsequently, this submarining prediction model was applied to computer tomography (CT) measurements of human subjects in different seated postures (upright, reclined, and slouched), and submarining risks were calculated based on the developed model. RESULTS: FE simulations indicated that submarining was more likely to occur as the initial belt-pelvis angle approached zero and there was a smaller initial belt-ASIS overlap. The logistic regression analysis demonstrated that the initial belt-pelvis angle and belt-ASIS overlap were statistically significant for predicting submarining risk. The derived model effectively distinguished submarining occurrence based on the initial values of these two parameters. The application of the submarining model to CT measurements of human subjects showed that submarining risk was lower in the order of upright, slouched, and reclined postures. In the reclined posture, the high submarining risk was attributed to a small belt-ASIS overlap and a rearward-tilted pelvis angle; whereas in the slouched posture, the risk was mostly associated with a rearward-tilted pelvis angle. CONCLUSIONS: The submarining prediction model was developed based on the belt-pelvis angle and the belt-ASIS overlap. This predictive model may help to design restraint systems for various body types and seated postures of occupants.

Injury comparisons between paired drivers and front-seat passengers in frontal collisions using publicly available crash and injury data.

Forensic engineers and crash safety researchers sometimes use the injuries of a seatbelted occupant to infer the injury risk of an unbelted occupant in the same crash, had they instead been wearing a seatbelt. It is unclear, however, whether this inference is valid or how often two occupants in the same collision have similar injuries. Here, we sought to compare the injury outcomes between drivers and front-seat passengers in frontal collisions using real-world collision data. We compared the injury severity, quantified using the Abbreviated Injury Scale (AIS), of 22 injury categories between front-seat occupants with matching seatbelt use and airbag deployment in single-event frontal collisions recorded in the publicly available National Automotive Sampling System, Crashworthiness Data System (years 1993-2015) database to assess whether they had similar severity injuries. We analyzed the four combinations of seatbelt use and airbag deployment and all seatbelt/airbag conditions combined. In only 3 of 88 combinations of injuries and seatbelt/airbag conditions did more than 50% of occupant pairs have the same AIS score, although the related confidence intervals showed these proportions were not significantly greater than 50%. In contrast, we found 19 combinations of injuries and seatbelt/airbag conditions where one occupant was consistently injured more severely than the other. Our findings show that injury outcome is not similar for both front-seat occupants in the same frontal collision with similar seatbelt and airbag conditions; however, one may be able to predict that one occupant would be more severely injured than their fellow occupant.

Prevalence of intra-abdominal injury among patients with seatbelt signs, a systematic review and meta-analysis.

INTRODUCTION: The advancement of seat belts have been essential to reducing morbidity and mortality related to motor vehicle collisions (MVCs). The "seat belt sign" (SBS) is an important physical exam finding that has guided management for decades. This study, comprising a systematic review and random-effects meta-analysis, asses the current literature for the likelihood of the SBS relating to intra-abdominal injury and surgical intervention. METHODS: PubMed and Scopus databases were searched from their beginnings through August 4, 2023 for eligible studies. Outcomes included the prevalence of intra-abdominal injury and need for surgical intervention. Cochrane's Risk of Bias (RoB) tool and the Newcastle-Ottawa Scale (NOS) were applied to assess risk of bias and study quality; Q-statistics and I2 values were used to assess for heterogeneity. RESULTS: The search yielded nine observational studies involving 3050 patients, 1937 (63.5%) of which had a positive SBS. The pooled prevalence of any intra-abdominal injury was 0.42, (95% CI 0.28-0.58, I2 = 96%) The presence of a SBS was significantly associated with increased odds of intra-abdominal injury (OR 3.62, 95% CI 1.12-11.6, P = 0.03; I2 = 89%), and an increased likelihood of surgical intervention (OR 7.34, 95% CI 2.03-26.54, P < 0.001; I2 = 29%). The measurement for any intra-abdominal injury was associated with high heterogeneity, I2 = 89%. CONCLUSION: This meta-analysis suggests that the presence of a SBS was associated with a statistically significant higher likelihood of intra-abdominal injury and need for surgical intervention. The study had high heterogeneity, likely due to the technological advancements over the course of this study, including seat belt design and diagnostic imaging sensitivity. Further studies with more recent data are needed to confirm these results.

Wildlife-vehicle collisions: The disproportionate risk of injury faced by motorcyclists.

We applied a generalized linear mixed-effects model to determine the factors leading to injuries from wildlife-vehicle collisions (WVCs). We used the Police database representing WVCs which took place on the Czech road network between 2009 and 2022. The majority of WVCs in Czechia are with roe deer, followed by wild boar, i.e., both relatively small ungulates. Less than 2 % of these encounters ends with an injury to the motor vehicle occupants. We found that the probability of sustaining injury was systematically higher for motorcyclists than for car occupants. The odds of sustaining an injury during WVC were roughly 1600 times higher for motorcyclists than for car occupants. When applying an evading manoeuvre, the odds of sustaining an injury were approximately 68 times higher for car occupants while only 2.3 times higher for motorcyclists compared to a direct hit to an animal. The lack of helmets (for motorcyclists) and missing seat belts (for car occupants) were additional factors which made the outcomes worse for WVCs. While the acceptance of a direct hit (preceded by braking) seems to be a reasonable strategy for car drivers, WVC awareness (including maintaining a lower speed during critical times and places) should be raised among motorcyclists as both manoeuvres are almost comparably dangerous for them.

Massive haemothorax and haemorrhagic shock due to cervical vascular injury caused by a seat belt.

A woman in her 50s was transported to our hospital after experiencing a road traffic crash that led to a massive haemothorax and haemorrhagic shock due to a cervical vascular injury caused by the seat belt. Contrast-enhanced CT of the chest showed extravascular leakage of the contrast medium from the vicinity of the right subclavicular area and fluid accumulation in the thoracic cavity. The patient was intubated, and a thoracic drainage catheter was placed. She underwent angiography and embolisation of the right costocervical trunk, right thyrocervical trunk and right suprascapular artery using a gelatine sponge and 25% N-butylcyanoacrylate-Lipiodol. She was extubated on the second day after stabilisation of the respiratory and circulatory status. In cases where the bleeding vessel is known and an emergency thoracotomy can serve as a backup, embolisation by interventional radiology should be considered the initial treatment approach.

Study of AEB and active seat belt on driver injury in vehicle-vehicle frontal oblique crash.

The safety of vehicle occupants in oblique collision scenarios continues to pose challenges, even with the implementation of Automatic Emergency Braking (AEB) systems. While AEB reduces collision risks, studies indicate it may heighten injury risks for out-of-position (OOP) occupants. To counteract this issue, the integration of active seat belts in vehicles equipped with AEB systems is recommended. Firstly, this study established an oblique angle collision scenario post-AEB activation using data from the Chinese National Automobile Accident In-depth Investigation System (NAIS) database, analyzed through Prescan software. The dynamic response of the vehicle was examined. Following this, finite element (FE) models were validated to assess the effects of collision overlap rate, AEB braking strategy, and active seat belt pre-tensioning on occupant injuries and kinematics. Under specific collision conditions, the impact of the timing and amount of seat belt pre-tensioning, as well as airbag deployment timing on occupant injuries, was also explored. Findings revealed that a 75% collision overlap rate significantly increases driver injury risk. Active seat belts effectively mitigate injuries caused by OOP statuses during AEB interventions, with the lowest Weighted Injury Criterion (WIC) observed at a pre-tensioning time of 200 ms for active seat belts. The study further suggests that optimal results in reducing occupant injuries are achieved when active pre-tensioning seat belts are complemented by appropriately timed airbag deployment.

Seat belt syndrome with caecal perforation and Chance fracture in an adolescent.

Seat belt syndrome describes a combination of injuries a person restrained by a seat belt may have after a high-velocity motor vehicle crash. A seat belt-shaped bruise may be present across the torso. A Chance fracture is a horizontal vertebral fracture, resulting from spinal hyperflexion, and in disruption of the three columns of the vertebral bodies. Its association with intra-abdominal injury is rare in children. A male, in early adolescence, was involved in a high-energy car crash. A total-body CT scan highlighted lacerations of the anterolateral abdominal wall and an acute L4 Chance fracture. Another CT scan performed because of clinical deterioration, showed cecal perforation, caused by a mesenteric tear and non-displaced fracture of the left sacral ala. He underwent a right hemicolectomy with ileocolic anastomosis and protective ileostomy and was immobilised in a body jacket orthosis for 3 months. The ileostomy was closed 3 months later. At 2-year follow-up, he is well.