Ranking and selecting dangerous crash locations: correcting for the number of passengers and Bayesian ranking plots

INTRODUCTION: In this paper a sensitivity analysis is performed to investigate how big the impact would be on the current ranking of crash locations in Flanders (Belgium) when only taking into account the most serious injury per crash instead of all the injured occupants. RESULTS: Results show that this would lead to a different selection of 23.8% of the 800 sites that are currently considered as dangerous. CONCLUSIONS: Considering this impact quantity, the researchers want to sensitize government that giving weight to the severity of the crash can correct for the bias that occurs when the number of occupants of the vehicles are subject to coincidence. Additionally, probability plots are generated to provide policy makers with a scientific instrument with intuitive appeal to select dangerous road locations on a statistically sound basis. Impact on industry Considering the impact quantity of giving weight to the severity of the crash instead of to all the injured occupants of the vehicle on the ranking of crash sites, the authors want to sensitize government to carefully choose the criteria for ranking and selecting crash locations in order to achieve an enduring and successful traffic safety policy. Indeed, giving weight to the severity of the crash can correct for the bias that occurs when the number of occupants of the vehicles are subject to coincidence. However, it is up to the government to decide which priorities should be stressed in the traffic safety policy. Then, the appropriate weighting value combination can be chosen to rank and select the most dangerous crash locations. Additionally, the probability plots proposed in this paper can provide policy makers with a scientific instrument with intuitive appeal to select dangerous road locations on a statistically sound basis. Note that, in practice, one should not only rank the crash locations based on the benefits that can be achieved from tackling these locations. Future research is also needed to incorporate the costs of infrastructure measures and other actions that these crash sites require in order to enhance the safety on these locations. By balancing these costs and benefits against each other, the crash locations can then be ranked according to the order in which they should be prioritized.     

Case-control study of risk factors for fatal and non-fatal injury in crashes of rotary-wing aircraft

INTRODUCTION: There have been few studies of the risk factors for fatal injury in air crashes of rotary-wing aircraft, and none of risk factors for all serious injury (fatal and non-fatal) in these aircraft. The aim of the study was to identify the potentially modifiable risk factors for injury in civil rotary-wing aircraft crashes in New Zealand. METHOD: We analyzed records from all reported civil rotary-wing aircraft crashes in New Zealand between 1988 and 1994. Air crash data from the official databases were merged with nationwide injury records and information obtained from Coroner's files. Crashes where the pilot-in-command was fatally injured were compared with crashes where the pilot-in-command was not fatally injured on 50 variables, covering pilot, aircraft, environmental, and operational characteristics. A second analysis compared crashes where the pilot-in-command was seriously injured (either fatally or non-fatally) with crashes where the pilot-in-command was not hospitalized with an injury. A series of multivariate logistic regression analyses were conducted to estimate the odds associated with each of the factors identified by the univariate analyses. RESULTS: The most significant risk factors for all serious injury were: (a) not obtaining a weather briefing, (b) off-airport location of the crash site, (c) flights carried out for air transport purposes, and (d) non-solo flights. Other risk factors, significant for fatal injury only, included post-crash fire and the nature of the crash terrain. Factors within the control of the pilot, environmental, and flight characteristics are the key determinants of the injury outcome of civil rotary-wing aircraft crashes.     

汽车-护栏系统耐撞性研究的有限元模型

为了建立汽车及公路护栏组成的复杂系统的耐撞性分析模型,基于VPG与LS-DYNA软件平台,应用标准化建模方法,即通过设定建模原则,在充分利用VPG内置的标准模型数据库如悬挂、轮胎、假人、安全带等各种模型的基础上,采用分块建模法,分别建立汽车、护栏、座椅模型,定义好各自内部的接触;并利用VPG的“export”功能,生成各自的DYN文件;再利用生成的DYN文件,就可组合出汽车-护栏系统耐撞性研究的各种中间环节的有限元模型,最终实现“汽车-护栏-乘员-座椅-安全带”系统模型的一体化。仿真分析与试验结果的对比表明,笔者建立的模型具有足够的可信度,适合工程应用,并给出了一个应用示例。     

哈得油田污水循环利用技术的研究应用

针对哈得油田生产过程中存在的注水水量不够和蒸发池负荷过大的问题,哈得油田对蒸发池污水循环利用技术开展了论证和实践。通过对清洁生产技术的应用,哈得油田将外排污水回收循环利用,减少了清水用量,实现了哈得油田作业区污水零排放,为同行业开展污水循环利用提供参考和借鉴。     

飞机驾驶舱人机几何适配性评价指标研究

飞机驾驶舱人机几何适配性评价对于保障人机效能的充分发挥和飞行安全至关重要。针对一些评价指标制定了相关标准和规范,但未形成一套可操作的指标体系。针对该问题,提出采用改进德尔菲法建立飞机驾驶舱人机几何适配性评价指标体系。通过对现有相关标准、规范和技术数据进行分析研究,初步确定出38个评价指标。针对确定的指标,聘请了飞过多种型号飞机的23名现役有经验飞行员作为专家咨询人员进行了两轮咨询,在对咨询结果进行统计处理的基础上,筛选出了21个评价指标,该指标体系的建立为飞机驾驶舱人机几何适配性综合评价奠定了基础,也可为航空工程部门的评价工作提供科学依据,并有一定的指导作用和实用价值。     

The combined benefits of motorcycle antilock braking systems (ABS) in preventing crashes and reducing crash severity

Objective: Several studies have reported the benefits of motorcycle antilock braking systems (ABS) in reducing injury crashes, due to improved stability and braking performance. Both aspects may prevent crashes but may also reduce the crash severity when a collision occurs. However, it is still unknown to what extent the reductions in injury crashes with ABS may be due to a combination of these mechanisms.

Methods: Swedish hospital and police reports (2003–2012) were used. The risk for permanent medical impairment (RPMI) was calculated, showing the risk of at least 1 or 10% permanent medical impairment. In total, 165 crashes involving ABS-equipped motorcycles were compared with 500 crashes with similar motorcycles without ABS.

The analysis was performed in 3 steps. First, the reduction in emergency care visits with ABS was calculated using an induced exposure approach. Secondly, the injury mitigating effects of ABS were investigated. The mean RPMI 1+ and RPMI 10+ were analyzed for different crash types. The distributions of impairing injuries (PMI 1+) and severely impairing injuries (PMI 10+) were also analyzed. In the third step, the total reduction of PMI 1+ and PMI 10+ injured motorcyclists was calculated by combining the reductions found in the previous steps. An additional analysis of combined braking systems (CBS) together with ABS was also performed.

Results: The results showed that emergency care visits were reduced by 47% with ABS. In the second step, it was found that the mean RPMI 1+ and RPMI 10+ with ABS were 15 and 37% lower, respectively. Finally, the third step showed that the total reductions in terms of crash avoidance and mitigation of PMI 1+ and PMI 10+ injured motorcyclists with ABS were 67 and 55%, respectively. However, PMI 1+ and PMI 10+ leg injuries were not reduced by ABS to the same extent. Indications were found suggesting that the benefits of ABS together with CBS may be greater than ABS alone.

Conclusions: This article indicated that motorcycle ABS reduced impairing injuries, mostly due to fewer emergency care visits but also due to a reduction in crash severity. This may seem reasonable as the improved stability and braking performance provided by ABS could prevent some crashes but would also decrease crash severity if a collision still occurs. As suggested by previous studies, however, the lower extremities would be more exposed in a crash with ABS. It is recommended that future research should follow up these results with additional data.     

Small female rib cage fracture in frontal sled tests

Objectives: The 2 objectives of this study are to (1) examine the rib and sternal fractures sustained by small stature elderly females in simulated frontal crashes and (2) determine how the findings are characterized by prior knowledge and field data.

Methods: A test series was conducted to evaluate the response of 5 elderly (average age 76 years) female postmortem human subjects (PMHS), similar in mass and size to a 5th percentile female, in 30 km/h frontal sled tests. The subjects were restrained on a rigid planar seat by bilateral rigid knee bolsters, pelvic blocks, and a custom force-limited 3-point shoulder and lap belt. Posttest subject injury assessment included identifying rib cage fractures by means of a radiologist read of a posttest computed tomography (CT) and an autopsy. The data from a motion capture camera system were processed to provide chest deflection, defined as the movement of the sternum relative to the spine at the level of T8.

?A complementary field data investigation involved querying the NASS-CDS database over the years 1997–2012. The targeted cases involved belted front seat small female passenger vehicle occupants over 40 years old who were injured in 25 to 35 km/h delta-V frontal crashes (11 to 1 o'clock).

Results: Peak upper shoulder belt tension averaged 1,970 N (SD = 140 N) in the sled tests. For all subjects, the peak x-axis deflection was recorded at the sternum with an average of ?44.5 mm or 25% of chest depth. The thoracic injury severity based on the number and distribution of rib fractures yielded 4 subjects coded as Abbreviated Injury Scale (AIS) 3 (serious) and one as AIS 5 (critical). The NASS-CDS field data investigation of small females identified 205 occupants who met the search criteria. Rib fractures were reported for 2.7% of the female occupants.

Conclusions: The small elderly test subjects sustained a higher number of rib cage fractures than expected in what was intended to be a minimally injurious frontal crash test condition. Neither field studies nor prior laboratory frontal sled tests conducted with 50th percentile male PMHS predicted the injury severity observed. Although this was a limited study, the results justify further exploration of the risk of rib cage injury for small elderly female occupants.