Using head-on collisions to compare risk of driver death by frontal air bag generation: a matched-pair cohort study

US air bag regulations were changed in 1997 to allow tests of unbelted male dummies in vehicles mounted and accelerated on sleds, resulting in longer crash pulses than rigid-barrier crashes. This change facilitated depowering of frontal air bags and was intended to reduce air bag-induced deaths. Controversy ensued as to whether sled-certified air bags could increase adult fatality risk. A matched-pair cohort study of two-vehicle, head-on, fatal collisions between drivers involving first-generation versus sled-certified air bags during 1998-2005 was conducted by using Fatality Analysis Reporting System data. Sled certification was ascertained from public information and a survey of automakers. Conditional Poisson regression for matched-pair cohorts was used to estimate risk ratios adjusted for age, seat belt status, vehicle type, passenger car size, and model year for driver deaths in vehicles with sled-certified air bags versus first-generation air bags. For all passenger-vehicle pairs, the adjusted risk ratio was 0.87 (95% confidence interval: 0.77, 0.98). In head-on collisions involving only passenger cars, the adjusted risk ratio was 1.04 (95% confidence interval: 0.85, 1.29). Increased fatality risk for drivers with sled-certified air bags was not observed. A borderline significant interaction between vehicle type and air bag generation suggested that sled-certified air bags may have reduced the risk of dying in head-on collisions among drivers of pickup trucks.     

Seat belt use in cars with air bags.

Seat belt use was observed in 1,628 cars with air bags and manual belts and 34,223 cars with manual seat belts only. Sixty-six percent of drivers in cars with air bags wore seat belts compared to 63 percent of drivers in cars with manual belts only. The study found no evidence for the speculation that drivers with air bags will reduce their seat belt use because they believe an air bag alone provides sufficient protection.     

Automobile driver fatalities in frontal impacts: air bags compared with manual belts.

OBJECTIVES. The effectiveness of air bags was estimated in this study by comparing driver fatalities in frontal crashes with driver fatalities in nonfrontal crashes, for cars with air bags and manual belts and cars with manual belts only. METHODS. Fatal Accident Reporting System data for drivers fatally injured during 1985 to 1991 in 1985 to 1991 model year cars that were equipped with air bags in or before model year 1991 were analyzed. RESULTS. Driver fatalities in frontal crashes in air bag cars were 28% lower than those in comparable cars with manual belts only. This percentage was used for estimating the overall fatality reduction in air bag cars. The reduction was greater in large cars (50%) than in midsize cars (19%) or in small cars (14%). Air bags reduced driver fatalities in frontal crashes involving ejection by about 9%. Fatalities in frontal crashes among drivers who were reportedly using manual belts at the time of the crash were reduced by about 15%. The comparable reduction among drivers who were reportedly not using manual belts was 31%. CONCLUSION. It was estimated that air bags reduced the total number of all driver fatalities by about 19%.     

Efficacy of side air bags in reducing driver deaths in driver-side collisions

Side air bags, a relatively new technology designed to protect the head and/or torso in side-impact collisions, are becoming increasingly common in automobiles. Their efficacy in preventing US driver deaths among cars struck on the near (driver's) side was examined using data from the Fatality Analysis Reporting System and the General Estimates System. Risk ratios for driver death per nearside collision during 1999-2001 were computed for head/torso and torso-only side air bags in cars from model years 1997-2002, relative to cars without side air bags. Confounding was addressed by adjusting nearside risk ratios for front- and rear-impact mortality, which is unaffected by side air bags. Risk ratios were 0.55 (95% confidence interval: 0.43, 0.71) for head/torso air bags and 0.89 (95% confidence interval: 0.79, 1.01) for torso-only air bags. Risk was reduced when cars with head/torso air bags were struck by cars/minivans (significant) or pickup trucks/sport utility vehicles (nonsignificant). Risk was reduced in two-vehicle collisions and among male drivers and drivers aged 16-64 years. Protective effects associated with torso-only air bags were observed in single-vehicle crashes and among male and 16- to 64-year-old drivers. Head/torso side air bags appear to be very effective in reducing nearside driver deaths, whereas torso-only air bags appear less protective.     

Restraint use among northwest American Indian children traveling in motor vehicles

OBJECTIVES: We sought to estimate motor vehicle passenger restraint use among Northwest American Indian children 8 years old or younger and to determine factors associated with using proper (i.e., age and weight appropriate) passenger restraint systems. METHODS: We surveyed vehicles driven by members of 6 tribes in Idaho, Oregon, and Washington. Associations between proper restraint and child, driver, and vehicle characteristics were analyzed using logistic regression for clustered data. RESULTS: We observed 775 children traveling in 574 vehicles; 41% were unrestrained. Proper restraint ranged from 63% among infant seat-eligible children to 11% among booster seat-eligible children and was associated with younger child's age (odds ratio (OR) per year = 0.60; 95% confidence interval (CI) = 0.48, 0.75), seating location (OR front vs rear=0.27; 95% CI=0.16, 0.44), driver seat belt use (OR=2.39; 95% CI=1.51, 3.80), and relationship (OR for nonparent vs parent=0.28; 95% CI=0.14, 0.58). More than half of drivers felt children could use an adult seat belt earlier than recommended guidelines, and 63% did not correctly identify whether their tribe had child safety seat laws. CONCLUSIONS: Children in these communities are inadequately restrained. Restraint use was exceedingly low among booster-eligible children and children riding with unrestrained adults. Interventions emphasizing appropriate restraint use and enforcement of passenger safety laws could reduce the risk of injury or death in motor vehicle accidents.     

Air bags and passenger fatality according to passenger age and restraint use

BACKGROUND: Some children have been killed by air bags, leading to advice that young children should not sit in front of an active air bag. METHODS: We conducted a case-control study to estimate the association of passenger air bag presence with death, according to passenger age and seat belt use. We used data from crashes on U.S. public roads in 1992 through 1998. Cases (N = 20,987) were front seat passengers who died, and controls (N = 69,277) were a sample of survivors. RESULTS: Among restrained passengers, the adjusted relative risk of death for those with a passenger air bag was 0.79 (95% confidence interval [CI] = 0.66-0.94); for children 12 years or younger, the adjusted relative risk was 1.04 (0.65-1.67) [corrected], and for adults 20 years or older it was 0.75 (0.62-0.91) [corrected]. Among unrestrained passengers, the adjusted relative risk was 1.03 (CI = 0.81-1.30); for children 12 years or younger the adjusted relative risk was 1.37 (0.84-2.21) [corrected], and for adults 20 years or older it was 0.96 (0.75-1.24). CONCLUSIONS: Passenger air bags may be a hazard to unrestrained children and of little benefit to unrestrained adults. Our results support the advice that children younger than 13 years should not sit in front of an active air bag.     

Association of first- and second-generation air bags with front occupant death in car crashes: a matched cohort study

First-generation air bags entail a decreased risk of death for most front seat occupants in car crashes but an increased risk for children. Second-generation air bags were developed to reduce the risks for children, despite the possibility of decreasing protection for others. Using a matched cohort design, the authors estimated risk ratios for death for use of each generation of air bag versus no air bag, adjusted for seat position, restraint use, sex, age, and all vehicle and crash characteristics, among 128,208 automobile occupants involved in fatal crashes on US roadways during 1990-2002. The authors then compared adjusted risk ratios (aRRs) between the two generations of air bags. Among front seat occupants, the aRR for death with a first-generation air bag was 0.90 (95% confidence interval (CI): 0.86, 0.94); the aRR with a second-generation air bag was 0.89 (95% CI: 0.79, 1.00) (p = 0.83 for comparison of aRRs). Among children under age 6 years, the aRR with a first-generation air bag was 1.66 (95% CI: 1.20, 2.30), while the aRR with a second-generation air bag was 1.10 (95% CI: 0.63, 1.93) (p = 0.20 for comparison of aRRs). The differences in aRRs between first- and second-generation air bags among other subgroups were small and not statistically significant.     

The driver's role in fatal two-car crashes: a paired "case-control" study.

This population-based study examines drivers' characteristics associated with driving errors that resulted in fatal motor vehicle crashes. Routinely collected data from the Fatal Accident Reporting System were used to assess whether a driver initiated the crash (case) or was passively involved (control) in 6,506 two-car collisions (81% of 7,993 eligible events). A paired comparison of cases and controls avoided confounding by environmental factors, exposure to traffic, and differences in case fatality. The strongest predictor of crash initiation is alcohol (odds ratio (OR) = 11.5; 95% confidence interval (CI) 9.57-13.9). Odds ratios are elevated even at the lowest blood alcohol concentration levels and increase dramatically as alcohol levels rise. Drivers aged 40-49 years are least likely to initiate crashes; odds ratios rise in a U-shaped manner to 3.35 in teenagers (95% CI 2.72-4.13) and to 22.1 in drivers over 80 years (95% CI 14.2-34.5). Other risk factors for initiating a fatal crash are the following: not wearing a seat belt (OR = 1.54; 95% CI 1.35-1.75), driving without a valid driver's license (OR = 2.16; 95% CI 1.72-2.73), and having had a crash within the last year (OR = 1.21; 95% CI 1.07-1.38). Driving errors leading to fatal crashes do not occur at random, but are associated with specific driver characteristics. The risk factors for crash initiation among crash-involved drivers are similar to risk factors for crash involvement found in other studies. These findings suggest that driving errors often explain high rates of crash involvement, invite further use of crash initiation in traffic injury research, and underscore the value of population-based registries for analytic epidemiology.     

Causal influence of car mass and size on driver fatality risk

OBJECTIVES: This study estimated how adding mass, in the form of a passenger, to a car crashing head-on into another car affects fatality risks to both drivers. The study distinguished the causal roles of mass and size. METHODS: Head-on crashes between 2 cars, one with a right-front passenger and the other with only a driver, were examined with Fatality Analysis Reporting System data. RESULTS: Adding a passenger to a car led to a 14.5% reduction in driver risk ratio (risk to one driver divided by risk to the other). To divide this effect between the individual drivers, the author developed equations that express each driver's risk as a function of causal contributions from the mass and size of both involved cars. Adding a passenger reduced a driver's frontal crash fatality risk by 7.5% but increased the risk to the other driver by 8.1%. CONCLUSIONS: The presence of a passenger reduces a driver's frontal crash fatality risk but increases the risk to the driver of the other car. The findings are applicable to some single-car crashes, in which the driver risk decrease is not offset by any increase in harm to others. When all cars carry the same additional cargo, total population risk is reduced.     

Predictors of seat-belt use among school-aged children in two low-income Hispanic communities

OBJECTIVES: To examine the prevalence of seat belt use among school-aged children in low-income Hispanic communities. METHODS: We conducted unobtrusive observations of school-aged children (aged 5 to 12 years) traveling to and from nine elementary schools in two communities. We documented vehicle type, and belted status and seating position of children, driver, and other passengers. Results are presented as percentages with 95% confidence intervals (CIs). RESULTS: We observed 3651 children, of which restraint use could be determined for 2741. Overall, 29% of children were using seat belts. By seating location, 58% were in the front seat with 40% belted, and 42% were in the back seat with 14% belted. Children were most likely to be restrained when traveling in the front seat (40.0%, CI=37.6-42.5); traveling with a belted driver (42.4%, CI=40.0-44.8); or traveling without additional passengers (40.3%, CI=37.0-43.7) CONCLUSIONS: Seat belt use among children from this study population was below the national average and was alarmingly low among children in the back seat. While traveling, being belted in the back seat provides the most protection in a collision. Prevention efforts need to be based on an understanding of the barriers to restraint use for children traveling in the back seat.     

宜兴市2010年机动车驾乘人员安全带佩戴现况及态度调查

目的 了解宜兴市驾乘人员安全带佩戴现况及态度.方法 在市区内选取4个观察点,在不同的时间段对出租车、小轿车、面包车和“皮卡”4种车型的司机和前排乘车人安全带的佩戴情况进行观察.同一时期对驾驶人员进行有关安全带佩戴态度问卷调查.结果 共观察12 473辆车辆和司机以及4 182名前排乘车人.其中司机安全带佩戴率为19.9％;乘车人安全带佩戴率为3.5％.问卷调查了1 073名驾乘人员,选择经常佩戴的51.7％,有时佩戴的25.4％,不佩戴22.9％;不佩戴的原因最多的是感到束缚、感到不舒服.认为最有效的措施是重金处罚、交通事故报道佩戴安全带者幸免于难.在调整了性别、车型等因素后,司机不佩戴安全带会增加前排乘车人不佩戴的风险(OR=8.26,P＜0.001).结论 目前该市驾乘人员司机和前排乘车人安全带的佩戴意识达到一定水平,但实际佩戴率还比较低,亟需加强管理.     

宜兴市2009年机动车驾乘人员安全带佩戴情况调查

目的调查道路安全法规或条例出台5年后的2009年宜兴市机动车驾乘人员安全带佩戴情况及态度。方法在市区内选取4个观察点,在不同的时间段对出租车、小轿车、面包车和"皮卡"4种车型的司机和前排乘车人安全带的佩戴情况进行观察。结果 2009年共观察1816辆车辆和司机,以及661名前排乘车人。其中司机安全带佩戴率为31.1%,不佩戴率为68.9%;乘车人安全带佩戴率为6.1%,不佩戴率为93.9%。在调整了性别、车型等因素后,司机不佩戴安全带会增加前排乘车人不佩戴的风险(OR=2.19,P0.05)。调查了866名驾乘人员的认知态度,选择经常佩戴的占83.4%,有时佩戴的占10.5%,不佩戴的占6.2%;不佩戴的原因最多的是感到不舒服。认为最有效的措施是重金处罚和加强佩戴安全带者幸免于难的交通事故报道。结论目前该市驾乘人员司机和前排乘车人安全带的佩戴意识达到一定水平,但实际佩戴率还比较低,亟需加强管理。     

The use of seat belts on British motorways.

Evidence demonstrating the advantages of seat belts in improving safety of road travel is overwhelming and has resulted in government legislation. This study was performed to investigate compliance with this legislation by fast-moving traffic on British motorways, for which no previous data exists. Analysis of seat belt use by 2564 travellers in 1526 cars in October 1992 revealed the following rates of use: drivers 98%; front passengers 96%; rear seat passengers with available belts 53%. The overall low rate of rear seat restraint use was seen in all age groups except babies. When the study was repeated 8 months later, the rates of restraint amongst 3910 travellers in 1881 cars had not increased. In view of the continuing heavy death toll on British motorways and roads, there is an obvious need for measures to improve rear seat belt use. This would be most appropriately achieved by both enforcing and publicizing the current legislation.     

Agreement between two observers in the measurement of smoking and use of safety belt and cell phones in vehicles

The aim of this study was to assess the feasibility of direct observations of smoking and use of seat belts and cell phones in drivers in the city of Barcelona, and to analyze the agreement between two observers. We performed 315 pairs of observations. The simple percentage inter-observer agreement between driver and passenger smoking was 100% with a Kappa coefficient=1.0. There was high inter-observer agreement in measurement of cell phone use and the number of passengers aged less than 14 years old. The variable with the lowest agreement was the driver's age. In conclusion, direct observation studies are a good resource for monitoring smoking and use of seat belts and cell phones in the drivers of motor vehicles.     

Characteristics of Crashes With Farm Equipment That Increase Potential for Injury

CONTEXT: Crash fatality and injury rates are higher on rural roadways than other roadway types. Although slow-moving farm vehicles and equipment are risk factors on rural roads, little is known about the characteristics of crashes with farm vehicles/equipment. PURPOSE: To describe crashes and injuries for the drivers of farm vehicles/equipment and non-farm vehicles involved in an injury crash. Passengers are not included in this analysis. METHODS: Injury crashes were included that involved a farm vehicle/equipment and at least one non-farm vehicle reported in Iowa Department of Transportation crash data from 1995 to 2004. Odds ratios were calculated through logistic regression to identify increased odds for injury among drivers of non-farm vehicles and farm vehicles/equipment. We examined frequently occurring crash characteristics to identify crash scenarios leading to the highest odds for injury. FINDINGS: Non-farm vehicle drivers were 5.23 times more likely to be injured than farm vehicle/equipment drivers (95% CI = 4.12-6.46). The absence of restraint use was a significant predictor of injury for both farm vehicle/equipment drivers (OR = 2.85; 95% CI = 1.14-7.13) and non-farm vehicle drivers (OR = 2.53; 95% CI = 1.54-4.15). Crash characteristics increasing the odds of injury for non-farm vehicle drivers included speeding, passing the farm vehicle/equipment, driving on a county road, having a frontal impact collision, and crashing in darkness. Ejection was the strongest predictor of injury for the farm vehicle/equipment driver. CONCLUSION: Non-farm vehicle drivers were much more likely to be injured than farm vehicle/equipment drivers, suggesting that farm vehicle/equipment crash prevention should be a priority for all rural road users. Prevention strategies that reduce motor vehicle speed, assist in safe passing, increase seat belt use, and increase conspicuousness of the farm vehicle/equipment are suggested.     

Prevalence of mobile phone use while driving vehicles

OBJECTIVE: To estimate the prevalence of mobile telephone use while driving vehicles in the city of Lleida (Spain). METHODS: A random sample of 1536 cars passing through six intersections regulated by traffic lights in Lleida were selected (three with urban traffic and three with interurban traffic). Cyclists, motorcyclists and driving school cars were excluded. The variables studied were mobile telephone use, age, (18-40; 41-60; >61), sex, the presence of passengers, type of intersection (urban traffic/interurban traffic), day of the week (working day/weekend or holiday) and hour of the day (rush hour/non-rush hour). The prevalence of mobile telephone use was calculated in percentages with a 95% CI. The relationship among the dependent variable (mobile telephone use) and the other independent variables was studied using odds radios (OR) and 95% CI. RESULTS: A total of 1536 direct observations were made and mobile telephone use was detected in 50 drivers. The prevalence was 3.3 (95% CI, 2.4-4.3). The prevalence was higher in men (OR = 2.2; 95% CI, 1.0-5.7), in drivers aged more than 60 years old (OR = 2.2; 95% CI, 0.5-8,4) and in those aged 18-40 years old (OR =1.5; 95% CI, 0.8-3.0), in unaccompanied drivers (OR = 3.0; 95% CI, 1.5-6.3), in urban intersections (OR = 2.7; 95% CI, 1.2-5.9), on workdays (OR = 2.0; 95% CI, 0.9-4.4) and at the rush hour (OR =1.4; 95% CI, 0.8-2.4). CONCLUSIONS: The prevalence of mobile telephone use while driving vehicles can be considered high, because of the increase in car accidents. The profile of drivers using mobile telephones corresponds to men aged 18-40 years or more than 61 years, in urban intersections, without passengers, during workdays and at the rush hour. We recommend the implementation of measures to decrease the use of mobile telephones while driving.     

南京市2005-2007年机动车驾乘人员安全带佩戴情况调查

目的 调查道路安全法或条例出台3年后南京市机动车驾乘人员安全佩戴情况.方法 在市区内选取4个观察点,在不同时间段对出租车、小轿车(8座以内)、厢式小货车和"皮卡"4种车型的司机和前排乘车人安全带的佩戴情况进行观察.结果 2005-2007年共观察35 256辆车辆和司机,以及15 772名前排乘车人.其中司机安全带佩戴率为49.9%,不佩戴率和假戴率分别为44.1%和4.6%;乘车人安全带佩戴率为9.1%,不佩戴率90.9%.在调整了性别、车型等因素后,3年来无论是司机还是前排乘车人安全带佩戴率均呈现下降趋势(P<0.01),司机不佩戴安全带会增加前排乘车人不佩戴的风险(OR=8.10,P<0.01).结论 现有法律或条例在司机和乘牟人佩戴安全带方面并无具体的规定,妨碍了法律或条例的有效执行.     

Seat belt use among drinking drivers in Minnesota.

OBJECTIVES. Among the reasons cited for recent declines in alcohol-related traffic fatalities is the enactment of seat belt use laws by most states. It is suspected that drinking drivers are less likely to comply with such laws, although evidence on the relationship between belt use and drinking by drivers is sparse and conflicting. The purpose of this study was to examine the relationship of drinking to driver seat belt use. METHODS. Observational, self-report, and chemical breath test data were collected on nighttime drivers in 16 Minnesota communities during September, 1990. RESULTS. Drivers with an illegal blood alcohol concentration (> or = 100 mg/dL) were substantially less likely to be wearing a seat belt (odds ratio [OR] = 2.17). Belt use was also more common among females (OR = 2.02) and before midnight (OR = 1.47). Males who had been drinking were less likely to be belted. Belt use was related to drinking before, but not after, midnight. Belt use was not related to drinking status among college graduates, but it was strongly related to drinking status among those with less education. CONCLUSIONS. The present findings provide further argument for rapid implementation of passive countermeasures (airbags) and for development of creative, carefully focused interventions to target high-risk populations.     

Driver air bag effectiveness by severity of the crash

OBJECTIVES: This analysis provided effectiveness estimates of the driver-side air bag while controlling for severity of the crash and other potential confounders. METHODS: Data were from the National Automotive Sampling System (1993-1996). Injury severity was described on the basis of the Abbreviated Injury Scale, Injury Severity Score, Functional Capacity Index, and survival. Ordinal, linear, and logistic multivariate regression methods were used. RESULTS: Air bag deployment in frontal or near-frontal crashes decreases the probability of having severe and fatal injuries (e.g., Abbreviated Injury Scale score of 4-6), including those causing a long-lasting high degree of functional limitation. However, air bag deployment in low-severity crashes increases the probability that a driver (particularly a woman) will sustain injuries of Abbreviated Injury Scale level 1 to 3. Air bag deployment exerts a net injurious effect in low-severity crashes and a net protective effect in high-severity crashes. The level of crash severity at which air bags are protective is higher for female than for male drivers. CONCLUSIONS: Air bag improvement should minimize the injuries induced by their deployment. One possibility is to raise their deployment level so that they deploy only in more severe crashes.     

Effectiveness of a comprehensive multisector campaign to increase seat belt use in the greater Athens area, Greece. Hellenic Road Traffic Police Department

OBJECTIVES: This study assessed the effectiveness of a comprehensive campaign to increase seat belt use in Athens. METHODS: In 1996 a survey focusing on seat belt use was undertaken among occupants of 1400 passenger cars. From October 1997 to June 1998 the campaign was implemented; during the campaign, seat belt law enforcement was not intensified. In 1998 another inspection survey of 2250 cars was undertaken. RESULTS: The program brought only a 6% increase in compliance, but there was an estimated gain of about 50 averted deaths and 1500 averted injuries. CONCLUSIONS: An intensive campaign to increase seat belt use, conducted in the absence of increased law enforcement, resulted in moderate gains.