Is seat belt usage by front seat passengers related to seat belt usage by their drivers?

INTRODUCTION: Unrestrained drivers and passengers are involved in a significant amount of fatalities and injuries in motor-vehicle crashes in the United States. While the literature documents the effectiveness of seat belt usage in reducing crash outcomes, such as fatalities and the severity of injuries, there is a need to evaluate the impact of seat belt usage by drivers and passengers in their respective vehicles. These findings could help develop effective education and enforcement strategies to enhance occupant safety. METHOD: This paper summarizes a study comparing seat belt usage rates of drivers and passengers based on whether or not the driver uses a seat belt. Observational data from 50 sites in the state of Nevada over 3 years are used for analyses. The data are stratified based on the gender of the driver and passengers in the front seat of the vehicle and are based on area type (rural or urban). RESULTS: A comparison of the rates of seat belt usage across for the aggregated data and for various types of disaggregation and statistical analyses to compare the rates of seat belt use among passengers based on the use of seat belts by drivers confirms that when drivers use seat belts, their respective passengers are much more likely to use seat belts. Further, if drivers do not use seat belts, their passengers are not likely to use seat belts. This observation is comparable for male drivers and female drivers, and also for male passengers and female passengers. Further, there are no differences for combinations of the genders of the drivers and passenger (i.e., both male or female, or one male and one female). IMPACT ON INDUSTRY: These results suggest that education and enforcement strategies would benefit most by working toward increasing seat belt usage rates among drivers.     

State-level seat belt use in the United States, 2011–2016: Comparison of self-reported with observed use and use by fatally injured occupants

Introduction: Despite 49 states and the District of Columbia having seat belt laws that permit either primary or secondary enforcement, nearly half of persons who die in passenger vehicle crashes in the United States are unbelted. Monitoring seat belt use is important for measuring the effectiveness of strategies to increase belt use. Objective: Document self-reported seat belt use by state seat belt enforcement type and compare 2016 self-reported belt use with observed use and use among passenger vehicle occupant (PVO) fatalities. Methods: We analyzed the Behavioral Risk Factor Surveillance System (BRFSS) self-reported seat belt use data during 2011–2016. The Pearson correlation coefficient (r) was used to compare the 2016 BRFSS state estimates with observed seat belt use from state-based surveys and with unrestrained PVO fatalities from the Fatality Analysis Reporting System. Results: During 2011–2016, national self-reported seat belt use ranged from 86–88%. In 2016, national self-reported use (87%) lagged observed use (90%) by 3 percentage points. By state, the 2016 self-reported use ranged from 64% in South Dakota to 93% in California, Hawaii, and Oregon. Seat belt use averaged 7 percentage points higher in primary enforcement states (89%) than in secondary states (82%). Self-reported state estimates were strongly positively correlated with state observational estimates (r = 0.80) and strongly negatively correlated with the proportion of unrestrained PVO fatalities (r = −0.77). Conclusion: National self-reported seat belt use remained essentially stable during 2011–2016 at around 87%, but large variations existed across states. Practical Applications: If seat belt use in secondary enforcement states matched use in primary enforcement states for 2016, an additional 3.98 million adults would have been belted. Renewed attention to increasing seat belt use will be needed to reduce motor-vehicle fatalities. Self-reported and observational seat belt data complement one another and can aid in designing targeted and multifaceted interventions.     

Attitudes toward a primary seat belt law among adults in a rural state with a secondary seat belt law

Problem

Enforced primary seatbelt laws can reduce morbidity and mortality associated with motor-vehicle crashes. Constituent support is an important factor associated with legislator voting behavior toward injury prevention laws. Little is known about attitudes toward a primary seat belt law among adults in rural states without a primary seat belt law.

Methods

Data from the Behavioral Risk Factor Surveillance System (BRFSS) survey, a telephone survey of a representative sample of adults in Montana, were used to assess attitudes toward a primary seat belt law.

Results

Sixty-one percent of respondents supported a primary seat belt law. Using multiple logistic regression analyses, women (AOR 1.87; 95% CI 1.49-2.36), persons aged 65 years and older (1.45; 1.06-1.96), American Indians (2.71; 1.55-4.75), those with health insurance (1.51; 1.07-2.14), and those who reported always wearing their seat belt (4.05; 3.14-5.21) were more likely to support a primary seat belt law than respondents without these characteristics.

Conclusions

The majority of adults in a rural state support a primary seat belt law.     

Taxi driver seat belt wearing in Nanjing, China

Objective

To determine and validate patterns of seat belt use and attitudes of taxi drivers on wearing a seat belt following national and provincial seat belt legislation in 2004-2005. Design: Roadside daylight seat belt observation and interview survey methods were used, as well as observations from inside taxis during routine trips and a taxi driver focus group. The setting was Nanjing, Jiangsu Province, PR China in April of 2006 and 2007.

Main outcome measures

Prevalence of seat belt use and attitudes to wearing a seat belt were determined, as were vehicle and driver characteristics, and comparisons with other motor-vehicle driver's seat belt use and attitudes.

Results

Taxi drivers interviewed were predominantly male and aged 30-39 years. They spent more hours per week in their vehicles and had more driving experience than other drivers. Over half (56.2%) of taxi drivers interviewed reported that they always wore seat belts, while observation of taxi drivers showed lower wearing rates (i.e., roadside observation was 43.8%, and observation from inside taxis was 36.2%). Belt tampering was a practice of 12-15% of taxi drivers. “Fine avoidance, safety, high speed and long trips” were given as important reasons for wearing and “feeling trapped and uncomfortable” for not wearing. Seat belt reminder signs in taxis were common (82.6% of taxis), but did not appear to impact on driver seat belt use.

Conclusion

The four research methods found taxi drivers to have consistently low “correct wearing” rates.

Impact on industry

As in several other countries, taxi drivers are particularly resistant to seat belt use. Innovative strategies, including occupational health and safety approaches, may be required to achieve increased levels of seat belt use.     

Occupant responses in conventional and ABTS seats in high-speed rear sled tests

Objective: This study compared biomechanical responses of a normally seated Hybrid III dummy on conventional and all belts to seat (ABTS) seats in 40.2 km/h (25 mph) rear sled tests. It determined the difference in performance with modern (≥2000 MY) seats compared to older (<2000 MY) seats and ABTS seats.

Methods: The seats were fixed in a sled buck subjected to a 40.2 km/h (25 mph) rear sled test. The pulse was a 15 g double-peak acceleration with 150 ms duration. The 50th percentile Hybrid III was lap–shoulder belted in the FMVSS 208 design position. The testing included 11 <2000 MY, 8 ≥2000 MY, and 7 ABTS seats. The dummy was fully instrumented, including head accelerations, upper and lower neck 6-axis load cells, chest acceleration, thoracic and lumbar spine load cells, and pelvis accelerations. The peak responses were normalized by injury assessment reference values (IARVs) to assess injury risks. Statistical analysis was conducted using Student's t test. High-speed video documented occupant kinematics.

Results: Biomechanical responses were lower with modern (≥2000 MY) seats than older (<2000 MY) designs. The lower neck extension moment was 32.5 ± 9.7% of IARV in modern seats compared to 62.8 ± 31.6% in older seats (P =.01). Overall, there was a 34% reduction in the comparable biomechanical responses with modern seats. Biomechanical responses were lower with modern seats than ABTS seats. The lower neck extension moment was 41.4 ± 7.8% with all MY ABTS seats compared to 32.5 ± 9.7% in modern seats (P =.07). Overall, the ABTS seats had 13% higher biomechanical responses than the modern seats.

Conclusions: Modern (≥2000 MY) design seats have lower biomechanical responses in 40.2 km/h rear sled tests than older (<2000 MY) designs and ABTS designs. The improved performance is consistent with an increase in seat strength combined with improved occupant kinematics through pocketing of the occupant into the seatback, higher and more forward head restraint, and other design changes. The methods and data presented here provide a basis for standardized testing of seats. However, a complete understanding of seat safety requires consideration of out-of-position (OOP) occupants in high-speed impacts and consideration of the much more common, low-speed rear impacts.     

The impact of state level behavioral regulations on traffic fatality rates

Introduction

A state by year panel is analyzed to simultaneously explore the statistical correlation between state level traffic fatality rates and state level behavioral regulations regarding teen licensing, seat belt use, and driving under the influence (DUI) in a model that also controls for other correlates.

Method

By including measures of all three of these policies, the estimated policy effects should not be overstated due to underspecification bias. The panel includes the 48 contiguous U.S. states for the time period from 1999 through 2003. State fatality rates are measured as fatalities per million miles traveled. Measures of state policies regarding traffic safety related behavior are based on information gathered by the Insurance Institute for Highway Safety. Estimates are calculated via a time fixed effects model that uses the double-log form to allow for interaction effects between the independent variables.

Results

Least squares estimates indicate that, on average, more restrictive graduated teen licensing and DUI policies significantly reduce traffic fatality rates, while stricter seat belt enforcement policies have a statistically insignificant negative impact on fatality rates.     

秦岭油松林不同坡位土壤CO2、CH4、N2O通量研究

在秦岭南坡火地塘林区天然次生油松林内选取上、中、下3个坡位,采用静态箱-气相色谱法对土壤CO_2、CH_4、N_2O通量进行了1年的监测.结果表明,坡位间土壤质地和水分的差别是引起不同坡位CO_2与N_2O通量差异的主要原因:下坡位土质为壤土,水分适宜,CO_2平均排放量为(156.49±9.72)mg·m~(-2)·h~(-1),CH_4平均吸收量为(77.43±14.27)μg·m~(-2)·h~(-1),都处于3个坡位间最高水平;中坡位土质为粉砂壤土,土壤粒径小,透气性差,CO_2排放量和CH_4吸收量均为3个坡位间的最小值,N_2O平均排放量为(9.57±0.66)μg·m~(-2)·h~(-1),为3个坡位间的最高值,且显著高于上坡位土壤N_2O通量(p0.01);上坡位土质为砂壤土,土壤孔隙度大且地表植被少,N_2O平均排放量为(5.59±0.74)μg·m~(-2)·h~(-1),为3个坡位间的最小值.总体来说,油松林土壤是CO_2、N_2O的排放源,是CH_4的吸收汇.3个坡位CO_2年通量具有明显的季节规律,表现为倒"S"形变化,且与土壤温度显著正相关(p0.01).受冻融循环的影响,N_2O主要在非生长季大量排放;生长季末期,受降雨事件影响,油松林中坡位出现N_2O吸收峰值.生长季上、下坡位CH_4吸收峰值的出现同样伴随着降雨事件的发生,非生长季,中坡位因土壤水分过高而出现短暂的CH_4排放现象.不同坡位土壤温室气体的全球增温潜势(Global Warming Potential,GWP)从大到小依次是上坡位、下坡位和中坡位.     

水热条件对不同坡位兴安落叶松林土壤CH4通量的影响

兴安落叶松林是我国北方最大的针叶林,在我国具有重要的碳汇地位,对我国以及全球的气候变化具有重要影响。由于独特的高寒高湿和多年冻土的特殊生态环境,兴安落叶松林土壤中 CH4的吸收与释放的规律与众不同。因此,开展对土壤 CH4动态及其与环境关系的研究,对揭示兴安落叶松林碳汇能力的形成、碳释放动态以及兴安落叶松林对气候变化的作用具有重要的理论和实践意义。作者于2011年5月到9月间在内蒙古根河国家生态站,在不同坡位的4种典型兴安落叶松林群落中布设样地,采用静态箱-红外气体分析仪收集气体并分析CH4通量的变化,同时测定不同深度的土壤温度,测定土壤含水率。借助SAS方差分析、相关性分析等统计方法,对兴安落叶松林土壤CH4通量的季节变化进行研究,同时分析土壤温度及含水率对 CH4通量的影响。结果表明,CH4的季节动态变化规律：坡顶 CH4通量为春季释放,夏季吸收,秋季释放,吸收大于释放,通量的平均值为-68.12μg·m^-2·h^-1;坡上部CH4通量为春夏秋3季均吸收,通量的平均值为-342.49μg·m^-2·h^-1;坡下部CH4通量为春季释放,夏季吸收,秋季释放,释放大于吸收,通量的平均值为67.8μg·m^-2·h^-1;坡脚CH4通量为春夏秋3季均释放,通量的平均值为263μg·m^-2·h^-1。总的来说,在生长季兴安落叶松林土壤甲烷通量吸收大于释放,说明地处寒温带的大兴安岭是CH4的汇。观测期间CH4通量与温度及土壤含水率均有一定的相关性,二者从不同角度影响CH4通量的变化,而随着坡位的变化土壤水热条件也随之改变,这同样是影响CH4通量的一个重要因素。     

Effects of cross-wise obstacle position on methane–air deflagration characteristics

A vented chamber, with internal dimensions of 150 mm × 150 mm × 500 mm, is constructed in which the premixed methane–air deflagration flame, propagating away from the ignition source, interacts with obstacles along its path. Three obstacle configurations with different cross-wise positions are investigated. The cross-wise obstacle positions are found to have significant effects on deflagration characteristics, such as flame structure, flame front location, flame speed, and overpressure transients. The rate of flame acceleration, as the flame passes over the last obstacle, is the highest at the configuration with three centrally located obstacles, whereas the lowest is observed at the configuration with three obstacles mounted on one side of the chamber. Compared with the side configuration, the magnitude of overpressure generated increases by approximately 80% and 165% for the central and staggered configurations, respectively. Furthermore, flame propagation speeds and generated overpressures for both the central and staggered configurations are greater, which should to be avoided to reduce the risk associated with turbulent premixed deflagrations in practical processes.