Protective effect of rear-seat restraints during car collisions

Motor Vehicle Crash and Hospital Charges in Front- and Rear-Seated Restrained and Unrestrained Adult Motor Vehicle Occupants

There are reports that historically higher mortality observed for front- compared to rear-seated adult motor vehicle (MV) occupants has narrowed. Vast improvements have been made in strengthening laws and restraint use in front-, but not rear-seated occupants suggesting there may be value in expanding the science on rear-seat safety.

METHODS

A linked 2016-2017 hospital and MV crash data set, the Crash Outcomes Data Evaluation System (CODES), was used to compare characteristics of front-seated (n = 115,939) and rear-seated (n = 5729) adults aged 18 years and older involved in a MV crash in New York State (NYS). A primary enforced seat belt law existed for front-seated, but not rear-seated occupants. Statistical analysis employed SAS 9.4.

RESULTS

Compared to front-seated occupants, those rear-seated were more likely to be unrestrained (21.2% vs. 4.3%, p < 0.0001) and to have more moderate-to-severe injury/death (11.9% vs. 11.3%, p < 0.0001). Compared to restrained rear-seated occupants, unrestrained rear-seated occupants had higher moderate-to-severe injury/death (21.5% vs. 7.5%, p < 0.0001) and 4-fold higher hospitalization. More than 95% of ejections were unrestrained and had 7-fold higher medical charges. Unrestrained occupants' hospital stays were longer, charges and societal financial costs higher.

CONCLUSIONS

These findings extend the science of rear-seat safety in seriously injured rear-seated occupants, document increased medical charges and support the need to educate consumers and policy makers on the health and financial risks of adults riding unrestrained in the rear seat. The lack of restraint use in adult rear-seated motor vehicle occupants consumes scarce health care dollars for treatment of this serious, but largely preventable injury.

Road traffic accidents in children: the 'what', 'how' and 'why'

INTRODUCTION

Road traffic accidents (RTAs) in Singapore involving children were evaluated, with particular focus on the epidemiology, surrounding circumstances and outcomes of these accidents. Key factors associated with worse prognosis were identified. We proposed some measures that may be implemented to reduce the frequency and severity of such accidents.

METHODS

This was a retrospective study of RTAs involving children aged 0-16 years who presented to the Children's Emergency at KK Women's and Children's Hospital, Singapore, from January 2011 to June 2014. Data was obtained from the National Trauma Registry and analysed in tiers based on the Injury Severity Score (ISS).

RESULTS

A total of 1,243 accidents were reviewed. RTA victims included motor vehicle passengers (60.4%), pedestrians (28.5%), cyclists (9.9%) and motorcycle pillion riders (1.2%). The disposition of emergency department (ED) patients was consistent with RTA severity. For serious RTAs, pedestrians accounted for 63.6% and 57.7% of Tier 1 (ISS > 15) and Tier 2 (ISS 9-15) presentations, respectively. Overall use of restraints was worryingly low (36.7%). Not restraining increased the risk of serious RTAs by 8.4 times. Young age, high ISS and low Glasgow Coma Scale score predicted a longer duration of intensive care unit stay.

CONCLUSION

The importance of restraints for motor vehicle passengers or helmets for motorcycle pillion riders and cyclists in reducing morbidity requires emphasis. Suggestions for future prevention and intervention include road safety education, regulation of protective restraints, use of speed enforcement devices and creation of transport policies that minimise kerbside parking.

Factors associated with mortality in rear-seated adult passengers involved in fatal motor vehicle crashes on US roadways

BACKGROUND

Recent efforts to pass rear seat belt laws for adults have been hampered by large gaps in the scientific literature. This study examines driver, vehicle, crash, and passenger characteristics associated with mortality in rear-seated adult passengers.

METHODS

The Fatality Analysis Reporting System (FARS) 2010 to 2011 was used to examine motor vehicle occupant mortality in rear-seated adult passengers 18 years and older. Side crash vehicle safety ratings were assessed in a subset analysis of vehicles struck on the same side as the rear-seated passenger. Multilevel logistic regression models used SAS GLIMMIX.

RESULTS

Of the 7,229 rear-seated adult passengers, 2,091 (28.9%) died. Multivariable predictors of increased mortality were advancing passenger age, younger driver age, excessive speed, ejection, being unbelted, rear impact, and same-side crash. Belt use was associated with a 67.0% reduction in total mortality. Despite this, belt wearing was low (48.1%) and differed by seating position, with less than one third of middle-seated passengers belted. Multivariable analysis showed mortality to be nearly three times higher in same-side crashes than other impact locations (odds ratio (OR) = 2.76, 2.22, 3.44). In a multivariable subpopulation analysis of same-side crashes, right-seated passengers had an increased mortality (52.7% vs. 43.2%, p < 0.01) compared to left-seated passengers (OR = 1.55, 1.02, 2.36). Vehicle side crash safety ratings, available for 27.7% (n = 172) of same-side crashes, were not predictive of mortality.

CONCLUSIONS

Except for same-side crashes, seat belts were associated with significantly lowered mortality. Despite this, seat belt wearing was low and represents one of several areas where further improvements in mortality might be realized.

Fatalities of children 0-7 years old in the second row

OBJECTIVE

The safety of children riding in the second-row of light vehicles remains an important issue. This study investigates fatal accidents of children 0-7 years old by seating position and principal direction of force. It considers the number of fatalities, exposure, and risk.

METHODS

The 1996-2005 FARS was analyzed for occupant fatalities by age (0-7 and >or= 8 years old), seating position (front, second, and third-row, and left, middle and right) and principal direction of force (1-12 o'clock PDOF, rollover, and other/unknown). Light vehicles were included with model year 1990+. The 1996-2005 NASS-CDS was similarly analyzed for occupant exposure. Fatality risk was defined as the number of fatalities in FARS divided by the exposure from NASS-CDS for each seating position and crash direction.

RESULTS

Two thirds (67.8%) of 0-to 7-year-old child fatalities occupied second-row-seats in FARS. A nearly equal number died in rollovers (20.3%), front impacts (20.2%), and side crashes (19.6%). About 354 deaths occur to second-row-seated children annually. A majority (76.6%) of children ride in the second-row based on tow away crashes in NASS-CDS. Most are exposed to front impacts (41.6%), followed by side impacts (16.5%). Rollovers are the lowest frequency (5.0%). However, fatality risk is highest in rollovers (1.37%), followed by right-side (0.47%) and left-side impacts (0.34%). Near-seated children in the second-row have a 3.04% fatality risk for right-side (3 o'clock) impacts. This is nearly twice the 1.53% risk for near-side second-row children in left-side (9 o'clock) impacts. Overall, right-side impacts have a 37% higher fatality risk than left-side impacts, irrespective of second-row seating position. The second-row has a 43.4% lower fatality risk than the front seat (0.30% v 0.53%) and the third-row is 58.5% lower (0.22% v 0.53%) for 0-to 7-year-old children. Overall, children seated behind the driver have an 8.1% lower fatality risk than those seated behind the right-front passenger, although the center second-row-seat has the lowest risk (0.27%). Children in the second-row have a 65-71% lower fatality risk than the driver with the lowest relative risk in the center second-row-seat (0.29) and highest in the second-row right position (0.35).

CONCLUSIONS

Children seated behind the driver have a lower fatality risk than those seated behind the right-front passenger. The higher risk to right second-row children is from near-side impacts at 3-4 o'clock and rollovers. In terms of priorities, rollovers, side impacts, and frontal crashes cause most fatalities. The highest risks for 0-to 7-year-old children in the second-row are in near-side impacts and rollovers.

Effects of seating position and appropriate restraint use on the risk of injury to children in motor vehicle crashes

BACKGROUND

Currently, many states are upgrading their child restraint laws to include provisions for the use of age-appropriate restraints through 6 to 8 years of age, with some also requiring rear seating for children, enabling the laws to be in closer alignment with best-practice recommendations.

OBJECTIVE

To evaluate the relationships of seating position and restraint status to the risk of injury among children in passenger vehicle crashes.

METHODS

This was a cross-sectional study of children <16 years of age who were involved in crashes of insured vehicles in 15 states, with data collected via insurance claims records and a telephone survey. A probability sample of 17980 children in 11506 crashes, representing 229106 children in 146613 crashes, was collected between December 1, 1998, and November 30, 2002. Parent reports were used to define restraint status, seating position, and occurrence of clinically significant injuries, with the use of a previously validated instrument.

RESULTS

Approximately 62% of the children used seat belts, 35% used child restraints, and 3% used no restraint. Nearly 4 of 5 children sat in the rear seat, with one half of all children being restrained appropriately for their age in the rear, although this varied according to the age of the child. Overall, 1.6% of children suffered serious injuries, 13.5% had minor injuries, and 84.9% did not have any injury. Unrestrained children in the front were at the highest risk of injury and appropriately restrained children in the rear were at the lowest risk, for all age groups. Inappropriately restrained children were at nearly twice the risk of injury, compared with appropriately restrained children (odds ratio [OR]: 1.8; 95% confidence interval [CI]: 1.4-2.3), whereas unrestrained children were at >3 times the risk (OR: 3.2; 95% CI: 2.5-4.1). The effect of seating row was smaller than the effect of restraint status; children in the front seat were at 40% greater risk of injury, compared with children in the rear seat (OR: 1.4; 95% CI: 1.2-1.7). Had all children in the study population been appropriately restrained in the rear seat, 1014 serious injuries (95% CI: 675-1353 injuries) would have been prevented (with the assumption that restraint effectiveness does not depend on a variety of other driver-related, child-related, crash-related, vehicle-related, and environmental factors).

CONCLUSIONS

Age-appropriate restraint confers relatively more safety benefit than rear seating, but the 2 work synergistically to provide the best protection for children in crashes. These results support the current focus on age-appropriate restraint in recently upgraded state child restraint laws. However, it is important to note that considerable added benefit would be realized with additional requirements for rear seating.

Risk of injury for occupants of motor vehicle collisions from unbelted occupants

OBJECTIVE

Unbelted occupants may increase the risk of injury for other occupants in a motor vehicle collision (MVC). This study evaluated the association between occupant restraint use and the risk of injury (including death) to other vehicle occupants.

DESIGN

A population based cohort study.

SETTING

United States.

SUBJECTS

MVC occupants (n = 152 191 unweighted, n = 18 426 684 weighted) seated between a belted or unbelted occupant and the line of the principal direction of force in frontal, lateral, and rear MVCs were sampled from the 1991-2002 National Automotive Sampling System General Estimates System. Offset MVCs were not included in the study.

MAIN OUTCOME MEASURE

Risk ratios and 95% confidence intervals for injury (including death) for occupants seated contiguous to unbelted occupants compared to occupants seated contiguous to belted occupants. Risk ratios were adjusted for at risk occupant's sex, age, seating position, vehicle type, collision type, travel speed, crash severity, and at risk occupants' own seat belt use.

RESULTS

Exposure to unbelted occupants was associated with a 40% increased risk of any injury. Belted at risk occupants were at a 90% increased risk of injury but unbelted occupants were not at increased risk. Risks were similar for non-incapacitating and capacitating injuries. There was a 4.8-fold increased risk of death for exposed belted occupants but no increased risk of death for unbelted occupants.

CONCLUSIONS

Belted occupants are at an increased risk of injury and death in the event of a MVC from unbelted occupants.

Factors affecting injury severity to rear-seated occupants in rural motor vehicle crashes

Injury to rear-seat occupants (RSOs) has received little systematic study in the literature. Past studies have focused on patterns of injury presented to the emergency department, various aspects of restraint usage and injury, or specific populations of RSOs. This is the first systematic analysis of injury severity to RSOs. RSOs involved in motor vehicle crashes (MVCs) sustain injuries of equal severity as do front-seated occupants (FSOs) involved in the same crash. The setting was a rural North Carolina emergency department where patients were evaluated at the sole hospital for the county. The design was a 2-year retrospective review of all MVCs with RSOs occurring in Pitt County North Carolina in calendar years 1988 and 1989. The Wilcoxon Rank-Sum Test and Logistic Regression Analysis with Injury Severity Score (ISS) as the dependent variable were performed. Three hundred forty-six crashes involving 367 vehicles with RSOs and 1,273 occupants that sent 222 patients to the hospital. ISS was higher for unrestrained occupants (1.87 versus 0.51), occupants of vehicles driven by legally intoxicated drivers (4.04 versus 0.73), occupants between the ages of 30 and 59 years (1.06 versus 0.65) and FSOs (1.04 versus 0.85) (Wilcoxon Rank-Sum test P <.0002). Logistic regression analysis confirmed these findings with the exception of more severe injuries for the 30 to 59 age range and impact speed. The analysis failed in these 2 cases. Restraint usage offered the greatest protective effect (OR 0.37). Lesser protective effects were noted with rear seat occupancy (OR 0.43) and age < 13 years (OR 0.77). More severe injuries were predicted by driver intoxication (OR 2.5), and age > 60 years (OR 1.25). In our rural population, RSOs sustain less severe injuries than FSOs. Restraint usage and sober drivers provide a greater protective effect however. Seat location does not replace restraint usage or sobriety.

Effect of seating position and restraint use on injuries to children in motor vehicle crashes

OBJECTIVE

To determine the effect of restraint use and seating position on injuries to children in motor vehicle crashes, with stratification by area of impact.

METHODS

Children <15 years old involved in serious automobile crashes in Utah from 1992 through 1996 were identified from statewide motor vehicle crash records. Serious crashes are defined as those resulting in occupant injuries with broken bones or significant bleeding or property damage exceeding $750. Probabilistic methods were used to link these records with hospital records. Analysis used logistic regression controlling for age, restraint use, occupant seating position, and type of crash.

RESULTS

We studied 5751 children and found 53% were rear seat passengers. More than 40% were unrestrained. Sitting in the rear seat offered a significant protective effect (adjusted odds ratio: 1.7; 95% confidence interval: 1.6-2.0), and restraint use enhanced this effect (adjusted odds ratio: 2.7; 95% confidence interval: 2.4-3.1). Mean hospital charges were significantly greater for front seat passengers.

CONCLUSIONS

Rear seat position during a motor vehicle crash provides a significant protective effect, restraint use furthers this effect, and usage rates of restraint devices are low. The rear seat protective effect is in addition to and independent of the protection offered from restraints.

Rate, causes and prevention of deaths from injuries in south-east Scotland

Data on all deaths after injuries in Lothian and Borders regions of south-east Scotland were collected prospectively over 2 years. Post-mortems were performed after all deaths and Injury Severity Scores (ISS) calculated. There were 331 deaths at a rate of 20 per 100,000 per year; of those who died 49 per cent were younger than 40 years and most were male; 37 per cent of deaths were caused by road traffic accidents, 16 per cent by falls and 15 per cent by hangings. Two hundred and forty-eight patients (75 per cent) were either dead when found or died instantly with unsurvivable injuries (ISS = 75). A further five patients died in the first hour after injury and before reaching hospital. Nineteen (7 per cent) died between 1 and 4 h after injury, 59 (17 per cent) died more than 4 h after. These results demonstrate the rate, causes and timing of deaths following injuries in one UK region. The pattern of these deaths differs markedly from that previously described in the US. There is no evidence to support the concept of a trimodal distribution of trauma deaths. The greatest potential to reduce the number of trauma deaths lies with prevention.

Paediatric road accidents in two health districts

For a 1-year period from 1 January 1990 all children seen, as a result of road traffic accidents (RTAs), in two accident and emergency departments (A&E), one in Liverpool and one in Chester were studied. Simple data were collected and injury severity scores (ISS) were used to assess injuries. Progress was monitored at 3 months post-injury by a review of hospital case notes. A total of 710 children fulfilled the study criteria in the year with a male:female ratio of 1.7:1. Only 37% of children were accompanied by an adult at the time of their accident. Overall 29% of children in vehicles were restrained and only three of 75 cyclists wore cycle helmets. Most injuries were minor with ISS of less than 9 in 96% of cases. Two children died after admission as a result of severe head injuries. The results were similar to those from other centres but highlight a need for continuing public education on child supervision, safe driving habits and the need for environmental changes.

Worldwide pattern of mortality from motor vehicle accidents, 1950-1990

Trends in age-specific and age-standardized death certification rates from motor vehicle accidents over the period 1950-1990 were analyzed for 48 countries from four continents (2 from North America, 10 from Latin America, 8 from Asia, 26 from Europe, Australia and New Zealand) on the basis of data produced by the World Health Organization mortality database. In most developed western and Asiatic countries, mortality rates increased until the late 1960's or early 1970's, and declined thereafter to reach values often lower than those of the early 1950's, although the number of circulating vehicles has substantially increased over the same calendar period. The extent of the decline was, however, different in various countries, as well as in the two sexes and in various age groups, thus leading to complex cohort and period patterns. In general, countries (like the U.S.A. or U.K.), where the number of motor vehicles had increased earlier, have now comparatively higher rates at younger than at middle and older age, while the opposite is observed in countries with later spread of motor vehicles. Further, there were a few countries, including Kuwait, Venezuela and several other Latin American countries, Australia and New Zealand, and several southern and eastern European countries, with exceedingly high rates from motor vehicle accidents, and where comprehensive interventions on this important cause of death are therefore a public health priority.

The effect of legislation on injuries sustained by rear seat car passengers

A study of 206 injured rear seat passengers was undertaken over two 4-month periods before and after the introduction of legislation enforcing use of rear seat-belts on 1 July 1991. The proportion of both adults and children using rear seat-belts increased after the law. Those wearing belts were less likely to suffer serious injury. The majority of passengers comply with the law but many rear seat passengers remain unrestrained because cars are not fitted with belts.

Prospective audit of the pattern, severity and circumstances of injury sustained by vehicle occupants as a result of road traffic accidents

The pattern and severity of injuries sustained by 174 vehicle occupants consecutively admitted to the Accident and Emergency Department of the Edinburgh Royal Infirmary were prospectively documented. Drivers (DR) accounted for 66% of the patients, 20% were front seat passengers (FSP) and 14% were rear seat passengers (RSP). Injured patients were more likely to be male, young, intoxicated and not wearing a seat-belt. The position of the patient within the vehicle at the time of the accident and point of impact significantly affected the pattern of injury sustained. The majority of injuries were sustained by the upper body and the pattern of injury is discussed. Most accidents occurred at low speeds and higher speeds were associated with an increased severity of injury. Seat-belts reduced the overall severity of injuries, in particular those to the face and chest, but may increase the risk of neck injury. Head-rests do not appear to influence the incidence of neck injury. Clinically apparent alcohol intoxication was associated with a markedly increased risk of severe injury.