Injury patterns of rear seat occupants in frontal impact: an in-depth crash investigation study

Incidence and Epidemiology of Thoracolumbar Spine Fractures: WFNS Spine Committee Recommendations

This review aims to search the epidemiology and incidence rates of thoracolumbar spine fractures. A systematic review of the literature of the last 10 years gave 586 results with “incidence,” and 387 results with “epidemiology,” of which 39 papers were analyzed. The review results were discussed and voted in 2 consensus meetings of the WFNS (World Federation of Neurosurgical Societies) Spine Committee. Out of 39 studies, 15 studies have focused on thoracolumbar trauma, remaining 24 studies have looked at all spine trauma. Most were retrospective in nature; few were prospective and multicenter. Some studies have focused on specific injuries. The annual incidence of TL fractures is about 30/100,000 inhabitants including osteoporotic fractures. There is a trend to increase the fractures in elderly population especially in developed countries, while an increase of motor vehicle accidents in developing countries. The mortality rate among male elderly patients is relatively high. The incidence of thoracolumbar spine fractures is increasing because of low-velocity falls in the elderly population. The main reasons are falls and traffic accidents. Learning the regional differences and some special forms of trauma such as extreme sports, war, and gunshot injuries will help the prevention of the thoracolumbar spine fractures.

U.S. vehicle occupancy trends relevant to future automated vehicles and mobility services

OBJECTIVE

Identifying current occupant travel patterns can inform decision making regarding the design, regulation, and occupant protection systems helpful for automated vehicle systems and mobility services.

METHODS

Two travel data sets were analyzed to quantify travel patterns: the 2017 National Household Travel Survey (NHTS), which provides data on household trips logged for a 24-h period, and the 2011-2015 National Automotive Sampling System-General Estimates System (NASS-GES), which contains data sampled from police-reported crashes. Analysis identified trends with driver age and gender, occupant age and gender, time of day, day of week, trip purpose, trip duration, vehicle type, as well as occupant role as solo driver, driver of others, single passenger, or multiple passengers.

RESULTS

In NHTS, the median trip duration is 15 min; only 10% of trips last longer than 40 min. Trip duration does not vary with occupant role or vehicle type. Variations with trip time of day and day of week show a unimodal pattern for weekends, as well as weekday trips for those aged 55 years and older and non-solo occupants aged 18 to 29 years. Other occupant groups have a bimodal weekday travel pattern with peak trips corresponding to morning and evening rush hours.In GES, approximately half of occupants are solo drivers. Female drivers aged 55 and older travel alone 60% of the time, and drivers under age 18 and female drivers aged 30 to 54 drive alone on less than 45% of trips. Approximately 13% of occupants are single passengers, and 16% travel with a driver and at least 1 other passenger. About 16% of occupants are front seat passengers.

CONCLUSIONS

This analysis of vehicle occupancy provides insights on what ridership of future automated vehicles and expanded ride-hailing services may look like. Because half of occupants are solo drivers, only 16% are multiple passengers, and median trip length is just 15 min, proposed alternative seating arrangements intended to promote comfort and passenger interaction may not represent the typical future vehicle use case in the United States. Knowledge of current occupancy patterns can help automated vehicle designers and regulators develop safe seating scenarios that meet customer needs.

Rear seating position is associated with a higher risk of mortality in motor vehicle crashes: analysis of Japanese Trauma Data Bank

Aim

The study examined the association of vehicle seating positions with the risk of death in serious motor vehicle crashes (MVCs) in Japan.

Methods

Data from the Japan Trauma Data Bank between 2004 and 2015 were analyzed. All MVC drivers with the legal age for driving and all copassengers were enrolled (n = 23,040). The cases were divided into three groups based on their seating position during the crash: the driver seat, front passenger seat, and rear passenger seats. The primary outcome variable was in‐hospital mortality. Multivariable logistic regression analysis was used to assess the association between the seating position and in‐hospital mortality. Potential factors associated with each seating position and in‐hospital mortality were also assessed.

Results

The odds ratios (ORs) for deaths were estimated for front and rear passengers compared to those for the driver in MVCs. The adjusted ORs (95% confidence interval [CI]) for death were 0.96 (0.84–1.11) and 1.22 (1.04–1.42) for front and rear passengers, respectively. Factors significantly associated with MVC deaths were age over 71 years (OR = 3.38; 95% CI, 2.58–4.41), male gender (OR = 1.54; 95% CI, 1.39–1.71), and night driving (OR = 1.17; 95% CI, 1.06–1.29).

Conclusions

This hospital‐based study suggested that rear seating increased the risk of MVC‐related death. Further studies are needed in order to find mechanisms of the increase in mortality by the seating position.

Factors contributing to serious and fatal injuries in belted rear seat occupants in frontal crashes

Objectives: Earlier research has shown that the rear row is safer for occupants in crashes than the front row, but there is evidence that improvements in front seat occupant protection in more recent vehicle model years have reduced the safety advantage of the rear seat versus the front seat. The study objective was to identify factors that contribute to serious and fatal injuries in belted rear seat occupants in frontal crashes in newer model year vehicles. Methods: A case series review of belted rear seat occupants who were seriously injured or killed in frontal crashes was conducted. Occupants in frontal crashes were eligible for inclusion if they were 6 years old or older and belted in the rear of a 2000 or newer model year passenger vehicle within 10 model years of the crash year. Crashes were identified using the 2004-2015 National Automotive Sampling System Crashworthiness Data System (NASS-CDS) and included all eligible occupants with at least one Abbreviated Injury Scale (AIS) 3 or greater injury. Using these same inclusion criteria but split into younger (6 to 12 years) and older (55+ years) cohorts, fatal crashes were identified in the 2014-2015 Fatality Analysis Reporting System (FARS) and then local police jurisdictions were contacted for complete crash records. Results: Detailed case series review was completed for 117 rear seat occupants: 36 with Maximum Abbreviated Injury Scale (MAIS) 3+ injuries in NASS-CDS and 81 fatalities identified in FARS. More than half of the injured and killed rear occupants were more severely injured than front seat occupants in the same crash. Serious chest injury, primarily caused by seat belt loading, was present in 22 of the injured occupants and 17 of the 37 fatalities with documented injuries. Nine injured occupants and 18 fatalities sustained serious head injury, primarily from contact with the vehicle interior or severe intrusion. For fatal cases, 12 crashes were considered unsurvivable due to a complete loss of occupant space. For cases considered survivable, intrusion was not a large contributor to fatality. Discussion: Rear seat occupants sustained serious and fatal injuries due to belt loading in crashes in which front seat occupants survived, suggesting a discrepancy in restraint performance between the front and rear rows. Restraint strategies that reduce loading to the chest should be considered, but there may be potential tradeoffs with increased head excursion, particularly in the absence of rear seat airbags. Any new restraint designs should consider the unique needs of the rear seat environment.