Feasibility Study of Airbag Concept Applicable to Motorcycles Without Sufficient Reaction Structure

Objectives: An airbag system for motorcycle applications was developed and marketed in 2006 followed by many research projects on the system. In the airbag system, the bag should be supported during the kinetic energy–absorbing period of a rider in a collision. The previously developed system employed a configuration in which motorcycle structures support the airbag, such as a gauge unit and/or a steering structure. The supporting structure functions to receive the reaction force to hold the airbag during a crash to properly absorb the rider's kinetic energy. However, the previous system requires a larger area for this reaction structure and is applicable only to the motorcycles that can provide that area. To overcome this limitation, we propose an airbag system employing another concept. In this concept, the airbag does not use its vehicle structures as a reaction structure but uses the structures of an opposing vehicle, such as doors and/or pillars of an opposing vehicle. In this project, we aim to verify the effectiveness of the proposed system when installed in a motorcycle that cannot provide a larger area for the reaction structure.

Methods: In the system with this concept, it is assumed that the occupant protection performance is largely affected depending on impact configurations. Accordingly, full-scale motorcycle-to-car crash tests using 125 cm³ scooter-type models with and without the proposed system were conducted in various impact configurations. The 7 impact configurations specified in ISO 13232 were selected as the test configurations. Injury variables and injury indices of head, neck, chest, and abdomen were evaluated with the motorcyclist dummy.

Results: Injury variables and indices obtained from the crash tests with the airbag were compared to those of the baseline tests. In 2 impact configurations, the airbags were supported by the side structures of the opposing vehicle and performed to reduce the injury variable of head and/or chest compared to that of the baseline test.

Conclusion: Through the crash tests, beneficial protection effects of the airbag system were confirmed in particular impact configurations. No significant risk for the occupant due to the airbag was observed in the conducted crash tests. It was concluded that the proposed airbag system has feasibility to reduce rider injury in a collision of a motorcycle without sufficient reaction structure.     

校车儿童安全气囊安全性仿真分析

为提高校车乘员约束系统在正面碰撞中对儿童乘员的保护效果,提出一种新型主动式校车儿童安全气囊。运用多刚体动力学分析软件MADYMO建立包括地板、前后排座椅、安全带与第5百分位女性假人在内的校车乘员正面碰撞仿真模型,通过台车试验结果验证模型的准确性。在此基础上,建立主动式安全气囊模型,研究其对12岁和6岁乘员的保护效果。用正交试验方法,分析气囊设计参数,针对12岁乘员进行气囊优化。结果表明:头部气囊的厚度及排气孔大小对乘员伤害影响最大。与原始约束系统相比,经优化后的气囊使12岁乘员的头部、胸部和颈部伤害分别下降84.5%,19%和84.3%,同时加装气囊对6岁儿童也有一定的保护效果。     

战场电磁兼容预测中的接收机建模研究

目的建立战场电磁兼容预测分析的接收机数学模型,包括接收机频率选择性模型、敏感度门限模型、互调模型及与接收机有关的修正系数计算模型等。方法在分析接收机干扰类型的基础上,建立上述数学模型,并探讨模型中的参数获取方法。结果给出了频率选择性模型分段折线斜率常数的获取方法,并对相关的互调系数、保护比等重要参数的实验测量方法进行了分析。结论建模结果可支持战场电磁接收装备仿真,为战场电磁兼容预测分析奠定基础。     

A conceptual framework to understand the role of built environment on traffic safety

IntroductionMany U.S. cities have adopted the Vision Zero strategy with the specific goal of eliminating traffic-related deaths and injuries. To achieve this ambitious goal, safety professionals have increasingly called for the development of a safe systems approach to traffic safety. This approach calls for examining the macrolevel risk factors that may lead road users to engage in errors that result in crashes. This study explores the relationship between built environment variables and crash frequency, paying specific attention to the environmental mediating factors, such as traffic exposure, traffic conflicts, and network-level speed characteristics. Methods: Three years (2011–2013) of crash data from Mecklenburg County, North Carolina, were used to model crash frequency on surface streets as a function of built environment variables at the census block group level. Separate models were developed for total and KAB crashes (i.e., crashes resulting in fatalities (K), incapacitating injuries (A), or non-incapacitating injuries (B)) using the conditional autoregressive modeling approach to account for unobserved heterogeneity and spatial autocorrelation present in data. Results: Built environment variables that are found to have positive associations with both total and KAB crash frequencies include population, vehicle miles traveled, big box stores, intersections, and bus stops. On the other hand, the number of total and KAB crashes tend to be lower in census block groups with a higher proportion of two-lane roads and a higher proportion of roads with posted speed limits of 35 mph or less. Conclusions: This study demonstrates the plausible mechanism of how the built environment influences traffic safety. The variables found to be significant are all policy-relevant variables that can be manipulated to improve traffic safety. Practical Applications: The study findings will shape transportation planning and policy level decisions in designing the built environment for safer travels.     

Alcohol policy and fatal alcohol-related crashes in Finland 2000–2016

Objective: The purpose of this study was to explore the relationship between annual alcohol consumption per capita/alcohol price index and the number of alcohol-related fatal motor vehicle accidents (AFMVAs). We were particularly interested in whether a tax reduction in 2004 increased the number of alcohol-related accidents.

Method: The data consisted of all fatal motor vehicle accidents (FMVAs) during the years 2000–2016 obtained from a database maintained by the Finnish Crash Data Institute (OTI). The data included all fatally injured drivers. We compared the OTI data to official statistics on annual alcohol consumption and the alcohol price index.

Results: There were 3,447 fatally injured drivers, of which 25% (n = 869) were intoxicated (blood alcohol concentration [BAC] ≥ 0.05%). After the reduction of the alcohol tax in 2004, the alcohol consumption rose 12.4% from 2003 to 2005 and AFMVAs rose 38%. There was a strong correlation (r = 0.7000, P < .018) between the recorded consumption of alcohol and the number of AFMVAs. There was a strong negative correlation between AFMVAs and the combined (retail + restaurant sales) alcohol price index (r = ?0.7863, P = .0005). A linear mixed-effects model showed that a 1-L increase in total alcohol consumption per capita per year increases AFMVAs by 10.6 and a one-unit increase in the price index decreases AFMVAs by 1.8 per year.

Conclusions: The correlation between alcohol consumption and alcohol-related crashes should be considered when making political decisions regarding alcohol price and availability. Any further liberalization of the alcohol policy would likely lead to an increase in alcohol-related fatal motor vehicle accidents. Similar consequences are likely to occur with drugs. Alcohol price policy is an effective way to improve road safety, but other measures taken to prevent FMVAs also seem to reduce the prevalence of AFMVAs.     

Development of injury risk models to guide CT evaluation in the emergency department after motor vehicle collisions

Abstract

Objective: The clinical evaluation of motor vehicle collision (MVC) victims is challenging and commonly relies on computed tomography (CT) to detect internal injuries. CT scans are financially expensive and each scan exposes the patient to additional ionizing radiation with an associated, albeit low, risk of cancer. Injury risk prediction based on regression modeling has been to be shown to be successful in estimating Injury Severity Scores (ISSs). The objective of this study was to (1) create risk models for internal injuries of occupants involved in MVCs based on CT body regions (head, neck, chest, abdomen/pelvis, cervical spine, thoracic spine, and lumbar spine) and (2) evaluate the performance of these risk prediction models to predict internal injury.

Methods: All Abbreviated Injury Scale (AIS) 2008 injury codes were classified based on which CT body region would be necessary to scan in order to make the diagnosis. Cases were identified from the NASS-CDS. The NASS-CDS data set was queried for cases of adult occupants who sought medical care and for which key crash characteristics were all present. Forward stepwise logistic regression was performed on data from 2010–2014 to create models predicting risk of internal injury for each CT body region. Injury risk for each region was grouped into 5 levels: very low (<2%), low (2–5%), medium (5–10%), high (10–20%), and very high (20%). The models were then tested using weighted data from 2015 in order to determine whether injury rates fell within the predicted risk level.

Results: The inclusion and exclusion criteria identified 5,477 cases in the NASS-CDS database. Cases from 2010–2014 were used for risk modeling (n?=?4,826). Seven internal injury risk models were created based on the CT body regions using data from 2010–2014. These models were tested against data from 2015 (n?=?651). In all CT body regions, the majority of occupants fell in the very low or low predicted injury rate groups, except for the head. On average, 57% of patients were classified as very low risk and 15% as low risk for each body region. In most cases the actual rate of injury was within the predicted injury risk range. The 95% confidence interval overlapped with predicting injury risk range in all cases.

Conclusion: This study successfully demonstrated the ability for internal injury risk models to accurately identify occupants at low risk for internal injury in individual body regions. This represents a step towards incorporating telemetry data into a clinical tool to guide physicians in the use of CT for the evaluation of MVC victims.     

Fatal crash between a car operating with automated control systems and a tractor-semitrailer truck

Abstract

Objective: The objective of this investigation was to evaluate the interaction between an SAE level 2 automated vehicle and the driver, including the limitations imposed by the vehicle on the driver.

Methods: A case study of the first fatal crash involving a vehicle operating with an automated control system was performed using scene evidence, vehicle damage, and recorded data available from the vehicle, and information from both drivers, including experience, phone records, computer systems, and medical information, was reviewed.

Results: System performance data downloaded from the car indicated that the driver was operating it using the Traffic-Aware Cruise Control and Autosteer lane-keeping systems, which are automated vehicle control systems within Tesla’s Autopilot suite. As the car crested the hill, a tractor trailer began its left turn onto a crossing roadway. Although reconstruction of the crash determined that there was sufficient sight distance for both drivers to see each other and take action, neither responded to the circumstances leading to the collision. Further, based on the speeds of the vehicles and simulations of the truck’s path, the car driver had at least 10.4?s to detect the truck and take evasive action. Neither the car driver nor the Autopilot system changed the vehicle’s velocity.

?At the time of the crash, the system performance data indicated that the last driver interaction with the system was 1?min 51?s prior when the cruise control speed was set to 74?mph. The driver was operating the vehicle using the Autopilot system for 37 of the 41?min in the last trip. During this period, the vehicle detected the driver’s hands on the steering wheel for a total of 25?s; each time his hands were detected on the wheel was preceded by a visual alert or auditory warning.

Conclusions: The National Transportation Safety Board (NTSB) determined that the probable cause of the Williston, Florida, crash was the truck driver’s failure to yield the right of way to the car, combined with the car driver’s inattention due to overreliance on vehicle automation, which resulted in the car driver’s lack of reaction to the presence of the truck. Contributing to the car driver’s overreliance on the vehicle automation was the car’s operational design, which permitted the driver’s prolonged disengagement from the driving task and his use of the automation in ways inconsistent with guidance and warnings from the manufacturer.     

Motor Vehicle Crashes on Bridges and Countermeasure Opportunities

There are approximately 600,000 highway bridges in the United States. These structures differ from surface streets and highways in terms of their physical properties and operational characteristics, which in turn, affect the risk of motor-vehicle crashes and the kinds of crashes that occur. The purpose of this study was to identify motor-vehicle crash patterns and contributing factors to bridge crashes and related countermeasure opportunities on four urban bridges in the New York metropolitan area. A crash typology was developed using the narratives and diagrams in police crash reports in addition to standard police classifications of crashes. The final dataset contained records of 1,381 police-reported crashes. The four bridges studied had higher crash rates than their respective approach roads. Four major crash types accounted for approximately 90% of the bridge crashes. Primary collision factors are reviewed, and potential countermeasures are discussed.     

航空机载产品磁影响测量分析

介绍了航空机载产品磁影响测量标准的技术要求和测量方法,深入剖析了磁影响测量的原理,澄清了标准中容易混淆的磁影响限值的确定原则,详细解释了磁强计测量磁影响的方法,经过实践检验,这种磁强计测量航空机载产品磁影响的方法准确可靠。     

油田污水去除成垢离子处理技术研究

在高效气浮除油、多种新型过滤分离技术的基础上,利用特种阴离子交换树脂去除油田污水中成垢离子的方法,解决了油田在注水开发中管线、设备及地层存在的结垢问题,处理后水质达到油田回注要求。同时在污水处理过程中,对"三废"的有效处置和循环使用,也达到了绿色环保的要求,为油田企业做进一步的实验和推广,起到一定作用。