Row Occupants Research Articles

Basilar, skull and facial fractures in 2nd row occupants by crash type with a focus on side and rear impacts

Objective Field data was analyzed to assess the risk of basilar, skull and facial fractures in 2nd row occupants by crash type. The study determined the rate of fractures in seriously injured (MAIS 3 + F) occupants to establish priorities for 2nd row occupant safety. Methods Field accident data on seriously injured (MAIS 3+) occupants was determined using 1993-2015 NASS-CDS and 2017-19 CISS by crash type identified with damage area variables for non-ejected occupants in the 2nd row. Occupants with serious head and face injuries (AIS 3+) were subdivided by fractures to the skull, basilar skull and face. Moderate-to serious (AIS 2+) orbit fractures were included. The rate of injury was determined. Individual electronic cases were analyzed for occupants with basilar fracture in rear and side impacts. Results The proportion of 2nd row occupants with AIS 3+ head and face injury was highest at 73.7% in rear impacts followed by side impacts at 54.2% for those with MAIS 3 + F injury. Basilar fractures (AIS 3+) occurred in 53.9% of 2nd row occupants with skull fracture in rear impacts but only 20.3% in side impacts. Overall, basilar fractures occurred in 10.8% of 2nd row occupants with serious injury (MAIS 3 + F) in rear impacts and 2.7% in side impacts. The frequency of AIS 3+ facial fractures was highest in side impacts (40.2%) and lowest (7.6%) in rear impacts. Conclusions While basilar skull fractures are rare in 2nd row occupants, at 0.083% in rear and 0.044% in side impacts, they represent 53.9% of 2nd row occupants with a skull fracture and serious injury in rear impacts and 20.3% in side impacts. The mechanism of injury is different in rear and side impacts, but frequently involves multi-impact crashes, severe impacts, intrusion into the seating area and head impact on hard surfaces.

Injuries Analysis of Rear Row Occupants Exposed to Vehicle’s Frontal Oblique Collision

Injuries Analysis of Rear Row Occupants Exposed to Vehicle’s Frontal Oblique Collision

Rear-seat occupant demographics in rear impacts: Analysis of NASS-CDS

Purpose This study analyzes field accidents to identify rear-occupant exposure and injury by crash types. Occupant demographics and injury were assessed by body region and crash severity to understand rear-occupant injury mechanisms in rear crashes. Methods The exposure and serious-to-fatal injury was determined by crash type for non-ejected second- and third- row occupants in 1994+ MY vehicles using 1994-2015 NASS-CDS. Selected occupant demographics and serious injury distributions were assessed over a range of delta V for rear crashes. Results Rear crashes accounted for 8.7% of exposed and 5.4% of serious-to-fatally injured rear-seat occupants. On average, rear-seat occupants were 14.3 ± 1.5 years old (median 10.3, 90th CI 0.08-29.6), weighed 44.7 ± 2.6 kg (median 44.4, 90th CI 7.9-81.7) and were 130.3 ± 4.1 cm tall (median 141.4, 90th CI 67.3-178.4). With serious injury, the average rear occupant was 18.1 ± 5.8 years old (median 13.1, 90th CI 0.0-47.2), weighed 42.6 ± 10.7 kg (median 31.4, 90th CI 7.0-82.4) and was 120.6 ± 15.4 cm tall (median 145.4, 90th CI 48.8-174.1). More than 72% of rear-seat occupants were in delta V less than 24 km/h. Less than 2% were in delta V 48 km/h or greater. The overall rate of serious-to-fatally injured (MAIS 3 + F) was 0.73% ± 0.37%. For serious-to-fatally injured rear-seat occupants, the average delta V was 37.4 ± 3.1 km/h (median 29.8, 90th CI 28.6-62.1). None were involved in delta Vs less than 24 km/h, about 78% were in a delta V between 24-48 km/h and 22% were in a delta V of 48 km/h or greater. Head and chest were most commonly injured, irrespective of crash severity. Conclusions The height and weight of a 10-year old and 5th Hybrid III ATD are representative of the average rear-seat occupant involved in rear crashes based on NASS-CDS. Crash tests with a delta V of between 30 and 37 km/h represent the typical collision causing serious-to-fatal injury.

The influence of coach interior partitions and seat leaf-tables on occupant injury in a frontal collision

For a typical coach, interior seats and partitions are considered as secondary collision objects in the event of a frontal collision. When a seat back has a deployable leaf-table, the additional effect of the leaf-table should be considered too. To investigate the effect of occupant collision with these objects, a full-scale frontal crash test of a coach was conducted with an impact velocity of 30 km/h. For virtual tests, a coupling model of partition-seat-occupants on a sled was established using the combination of LS-DYNA and MADYMO. It was validated using the full-scale test. The injury severity of the first row occupants was evaluated under different restraint conditions. Results show that occupants who are not belted and those with a lap belt only have the highest injury severity. A comparison of kinematics and injury characteristics between the first row occupants and the non-first row occupants was conducted to provide a comparative analysis.

Study on Rear Row Occupant Injury and Seat Optimization Based on C-NCAP Whiplash Test Method

In the field of whiplash test, there was a lack of regulations for evaluating the protective performance of rear seats. Referring to the C-NCAP front seat whiplash test method, this paper conducted the rear seat whiplash tests of 10 different models. The test results were presented. The reasons for the loss of NIC, Upper Fz and Upper My were analyzed. The optimization methods of the headrest were discussed and Suggestions on the optimization of rear seats were put forward.

Population-based assessment of a vehicle fleet with seat belts providing lower shoulder belt forces than today

Objective: The objective of this study was to quantify the population-based effects of a lower shoulder belt load limit on front row occupants in frontal car crashes.Method: Crashes of modern vehicles from the GIDAS (German In-Depth Accident Study) are corrected for bias and projected to the national level. Injury risk functions are computed for the injury severity levels Maximum Abbreviated Injury Scale (MAIS) 2+, MAIS 3+, and fatal, stratified by 2 age cohorts (16–44 years of age and 45 years or older). To assess the field effectivity of a “softer belt,” the projected crash frequency data are modified separately for the 2 age cohorts such that its risk structure represents the risk of a softer belt. Given those 2 samples, the field effectivity of a softer belt is derived for several shares of the younger age cohort according to the injury severity levels MAIS 2+, MAIS 3+, and fatal.Results: The injury risk distribution of the projected crash frequency data, represented here by the injury risk functions obtained, fits well into the injury risk distribution of other data sets (Sweden, United States, and Japan) given in the literature. The relative effects of a lower belt force are stable over the different ratios of the younger and old age cohorts. At the MAIS 2+ level, a lower belt force can significantly reduce the number of injuries (about 10%). A lower belt force does not significantly affect the number of MAIS 3+ injuries. A lower belt force can, however, more than double the number of fatal injuries.Conclusions: Because the number of fatal injuries rises dramatically due to lower belt force, the reduction in the number of MAIS 2+ injuries comes at a very high cost. Therefore, whether reducing the belt force limit is the right approach is questionable.

Injury severity data for front and second row passengers in frontal crashes.

The data contained here were obtained from the National Highway Transportation Safety Administration׳s National Automotive Sampling System – Crashworthiness Data System (NASS-CDS) for the years 2008–2014. This publically available data set monitors motor vehicle crashes in the United States, using a stratified random sample frame, resulting in information on approximately 5000 crashes each year that can be utilized to create national estimates for crashes. The NASS-CDS data sets document vehicle, crash, and occupant factors. These data can be utilized to examine public health, law enforcement, roadway planning, and vehicle design issues. The data provided in this brief are a subset of crash events and occupants. The crashes provided are exclusively frontal crashes. Within these crashes, only restrained occupants who were seated in the right front seat position or the second row outboard seat positions were included. The front row and second row data sets were utilized to construct occupant pairs crashes where both a right front seat occupant and a second row occupant were available. Both unpaired and paired data sets are provided in this brief.

Paired vehicle occupant analysis indicates age and crash severity moderate likelihood of higher severity injury in second row seated adults in frontal crashes

The majority of advances in occupant protection systems for motor vehicle occupants have focused on occupants seated in the front row of the vehicle. Recent studies suggest that these systems have resulted in lower injury risk for front row occupants as compared to those in the second row. However, these findings are not universal. In addition, some of these findings result from analyses that compare groups of front and second row occupants exposed to dissimilar crash conditions, raising questions regarding whether they might reflect differences in the crash rather than the front and second row restraint systems. The current study examines factors associated with injury risk for pairs of right front seat and second row occupants in frontal crashes in the United States using paired data analysis techniques. These data indicate that the occupant seated in the front row frequently experiences the more severe injury in the pair, however there were no significant differences in the rate of occurrence of these events and events where the more severe injury occurs in the second row occupant of the pair. A logistic regression indicated that the likelihood of the more severe injury occurring in the second row seated occupant of the pair increased as crash severity increased, consistent with data from anatomic test dummy (ATD) tests. It also indicated that the second row occupant was more likely to have the more severe injury in the pair if that occupant was the older occupant of the pair. These findings suggest that occupant protection systems which focus on providing protection specifically for injuries experienced by older occupants in the second row in higher severity crash conditions might provide the greatest benefit.

Rear seat safety: Variation in protection by occupant, crash and vehicle characteristics

ObjectivesCurrent information on the safety of rear row occupants of all ages is needed to inform further advances in rear seat restraint system design and testing. The objectives of this study were to describe characteristics of occupants in the front and rear rows of model year 2000 and newer vehicles involved in crashes and determine the risk of serious injury for restrained crash-involved rear row occupants and the relative risk of fatal injury for restrained rear row vs. front passenger seat occupants by age group, impact direction, and vehicle model year. MethodData from the National Automotive Sampling System Crashworthiness Data System (NASS-CDS) and Fatality Analysis Reporting System (FARS) were queried for all crashes during 2007–2012 involving model year 2000 and newer passenger vehicles. Data from NASS-CDS were used to describe characteristics of occupants in the front and rear rows and to determine the risk of serious injury (AIS 3+) for restrained rear row occupants by occupant age, vehicle model year, and impact direction. Using a combined data set containing data on fatalities from FARS and estimates of the total population of occupants in crashes from NASS-CDS, logistic regression modeling was used to compute the relative risk (RR) of death for restrained occupants in the rear vs. front passenger seat by occupant age, impact direction, and vehicle model year. ResultsAmong all vehicle occupants in tow-away crashes during 2007–2012, 12.3% were in the rear row where the overall risk of serious injury was 1.3%. Among restrained rear row occupants, the risk of serious injury varied by occupant age, with older adults at the highest risk of serious injury (2.9%); by impact direction, with rollover crashes associated with the highest risk (1.5%); and by vehicle model year, with model year 2007 and newer vehicles having the lowest risk of serious injury (0.3%). Relative risk of death was lower for restrained children up to age 8 in the rear compared with passengers in the right front seat (RR=0.27, 95% CI 0.12–0.58 for 0–3 years, RR=0.55, 95% CI 0.30–0.98 for 4–8 years) but was higher for restrained 9–12-year-old children (RR=1.83, 95% CI 1.18–2.84). There was no evidence for a difference in risk of death in the rear vs. front seat for occupants ages 13-54, but there was some evidence for an increased relative risk of death for adults age 55 and older in the rear vs. passengers in the right front seat (RR=1.41, 95% CI 0.94–2.13), though we could not exclude the possibility of no difference. After controlling for occupant age and gender, the relative risk of death for restrained rear row occupants was significantly higher than that of front seat occupants in model year 2007 and newer vehicles and significantly higher in rear and right side impact crashes. ConclusionsResults of this study extend prior research on the relative safety of the rear seat compared with the front by examining a more contemporary fleet of vehicles. The rear row is primarily occupied by children and adolescents, but the variable relative risk of death in the rear compared with the front seat for occupants of different age groups highlights the challenges in providing optimal protection to a wide range of rear seat occupants. Findings of an elevated risk of death for rear row occupants, as compared with front row passengers, in the newest model year vehicles provides further evidence that rear seat safety is not keeping pace with advances in the front seat.

Effect of Cargo Loading on Occupant Injury and Seat Deformation in Motor-Vehicle Crashes

Purpose: NHTSA studied interior loose objects in the 2000-04 NASS-CDS as part of rulemaking on cargo retention testing in FMVSS 208. This study extends the investigation of cargo and loose interior object loading on occupant injury and seat deformation by cargo in motor-vehicles crashes using NASS-CDS data.Methods: 1996-2011 NASS-CDS was used to investigate the effects of loose interior objects and seat responses on occupant injury in motor vehicle crashes. Crashes were grouped by front, side, rear and rollover. Light vehicles were included with model year 1994+. NASS-CDS added new variables for cargo loading as an injury source and cause for seat deformation in 2007. NASS-CDS electronic cases were analyzed for rear occupants with moderate to severe injury (AIS 2+) from loose objects and MAIS 4+F injury with cargo deforming seats in frontal crashes.Results: There were no AIS 2+ injuries due to cargo loading in the 16 years of NASS-CDS, including specific coding from 2007–11 and by case evaluation in earlier years. In frontal crashes, loose or other interior objects accounted for 250 AIS 2+ injuries in drivers, 32 in front passengers and 206 in 2nd row occupants. The overall rate of AIS 2+ injury was 1.000% for 2nd row occupants due to loose or other interior objects. The individual cases of AIS 2+ injury from loose or other interior objects in 2nd row occupants involved 16 occupants with 44 injuries in frontal crashes. Two cases involved police vehicles and one, an ambulance. In two other cases, the loose interior object was a bike placed in the 3rd row of a station wagon and an unsecured fan in the 2nd row. Each year, there were 540 driver seats deformed by cargo, 438 front-passenger seats and 889 in 2nd row seats. Most cargo deformation of front seats occurred in frontal crashes. Annually, there were 462 driver seats deformed by cargo in frontal crashes, 143 front-passenger seats and 660 in 2nd row seats.Conclusions: This analysis supports NHTSA's earlier conclusion that cargo is not a major source of injury in frontal crashes. While anecdotal cases have been presented in the literature, there were no cases in NASS-CDS. NASS-CDS also showed that when untethered cargo deforms rear seats, it was not related to severe injury to 2nd row occupants.

A Study of Occupant Ejection Mitigation During Rollovers for Front Row Occupants

A Study of Occupant Ejection Mitigation During Rollovers for Front Row Occupants

Front Seat Performance in Rear Impacts: Effect on 1stand 2ndRow Occupant Injury

Front Seat Performance in Rear Impacts: Effect on 1^stand 2^ndRow Occupant Injury

Seating Patterns and Corresponding Risk of Injury Among 0- to 3-Year-Old Children in Child Safety Seats

Current guidelines for optimal restraint of children in motor vehicles recommend the center rear seating location for installing a child-restraint system. However, recent research on child occupants in child-restraint system has brought this into question. The objective of this study was to describe seating position patterns among appropriately restrained child occupants aged 0 to 3 years in the rear row of vehicles. In addition, we determined the association between rear row seating location and risk of injury. We studied data collected on child occupants from December 1, 1998, to December 31, 2006, via insurance claim records and a validated telephone survey. The study sample included child occupants aged 0 to 3 years seated in a child-restraint system in the rear row of the vehicle, model year 1990 or newer, involved in a crash in 16 states. Children were classified as injured if a parent or driver reported an injury corresponding with Abbreviated Injury Scale scores of > or = 2. Seating position distribution for child occupants was as follows: left outboard (31%), center (28%), and right outboard (41%). There was an inverse relationship between the center position and increasing child age (39% for occupants < 1 year old versus 18% for occupants 3 years old), independent of the number of additional row occupants. Child occupants seated in the center had an injury risk 43% less than children seated in either of the rear outboard positions. The most common seating position for appropriately restrained child occupants in a child-restraint system is the right rear outboard. The center rear seating position is used less often by children restrained by a child-restraint system as they get older. Children seated in the center rear have a 43% lower risk of injury compared with children in a rear outboard position.

Modelling the effects of an inflatable tubular structure (ITS) on occupant kinematics and injury risk in the rollover of a sports utility vehicle (SUV)

The aims of this study are to investigate the responses of a Hybrid III dummy and a human body model in rollover crashes of an SUV, and to assess the effect of an inflatable tubular structure (ITS) on the unrestrained occupant kinematics in rollover events. A SAEJ2114 rollover test of a 1994 Ford Explorer with an inflatable tubular structure (ITS) is simulated for two front row occupants, and validated in MADYMO. By removing the ITS, the simulation of the Hybrid III dummy occupants without ITS is obtained. By replacing the dummy models with human body models, with and without ITS, two other simulations are also modelled. The kinematics and injury risks of the two occupant models are compared and evaluated. Significant differences exist in the motions, and injury levels of the dummies and human body models with and without ITS. ITS can offer significant protection to the head by cushioning the impact of the head on the roof or side windows, and can mitigate against occupant ejection. The flexibility of the spine and the neck of the human body models significantly affects the kinematics and the severity of the injuries of the occupants modelled, and so would also affect the relevance of the design of countermeasures developed from dummy tests to real-world rollover crashes of human beings.