Grandparents and child passenger safety

Purpose

This study compares child passenger safety (CPS) practices of grandparents versus parents and determines grandparents’ opinions on car safety seats (CSS), barriers to use, and ways to transport grandchildren safely.

Methods

Observational surveys were conducted on a convenience sample of drivers transporting children younger than sixteen years at 25 locations by certified child passenger safety technicians observing children in motor vehicles and recorded use of child passenger restraints. The drivers were surveyed on their knowledge, attitudes, beliefs, and practices regarding CPS. Data from drivers identifying themselves as grandparents were analyzed; also, three grandparent focus groups provided opinions on CPS practices.

Results

During the study 1758 parents transporting 2713 children and 284 grandparents transporting 391 grandchildren were included. While most drivers were restrained and used child occupant restraints, almost 25% of parents and grandparents chose the incorrect seat to transport the child, and greater than 68% had at least one harness error. Grandparents were more likely to have looser lower anchor straps or seat belts and have children younger than thirteen years in the front seat.The focus group-grandparents had a favorable attitude toward CSS. Grandparents acknowledged the need for CSS but opined that CSS were difficult to use. Physical barriers included arthritis, back pain, mobility, decreased strength, and vision problems.

Conclusions

Grandparents and parents were equally likely to use CSS and choose correct seats. Compared to parents, grandparents were more likely to travel with their grandchildren with CSS installed with looser harnesses or an installed CSS with looser seat belt or lower anchors. Additionally, grandparents were more likely to have a child younger than thirteen years in the front seat. The use of community resources such as permanent fitting stations could help grandparents improve a grandchild's travel safety.     

Evaluation of a child passenger safety class in increasing parental knowledge

Background

Child passenger restraint systems have been found to greatly reduce the risk of injury and death among child passengers. However, nearly half of the children who died in 2009 as a result of motor vehicle crashes were completely unrestrained. Our global hypothesis is that parents and other caregivers failed to restrain children due to a lack of child passenger seat education and practice. In this report, we postulate that a car seat class will improve the basic understanding of child passenger safety. The objective of the study was to evaluate the effectiveness of a car seat class in increasing parental knowledge about child passenger safety.

Methods

Car seat classes were held at a Level 1 pediatric trauma center every other Tuesday for ten months. The curriculum consisted of: child passenger safety laws discussion, a 21-min video on the use of child safety seats followed by a 15-min discussion about the video, 15 min of discussing the different types of car seats, and hands-on training on how to properly install and use child restraints. Free car seats were provided to eligible parents. The pre-test was administered at the beginning of class and the post-test at the end of the class. McNemar's test and a paired t-test were used to compare pre- and post-test scores. Test scores were also stratified by language spoken.

Results

Forty-four classes were held and a total of 491 parents/caregivers attended the classes. An increase in knowledge was found for all survey questions. Mean knowledge score for the post-test was 3.10 points higher compared to the mean knowledge score from the pre-test. Mean difference in knowledge scores for English-speaking participants were higher than Spanish-speaking participants.

Conclusion

Lack of knowledge and low risk perception have frequently been cited as barriers for the use of child passenger restraints. Our intervention attempted to eliminate these barriers. We found that this intervention was effective at increasing parental knowledge about child passenger safety. The results of this study may be used to design and implement future interventions in multicultural settings.     

The child support seat—A new type of protection system for the older child passenger

A protection system for the older child passenger consisting of a specially designed cushion has been allocated to 50 families. The parents completed a questionnaire and were interviewed following 3 months' and one year's use of the seats concerning their safety, comfort and handling qualities. These results are discussed as well as suggestions to manufacturers concerning the improvement of the system.     

Modelling of safety glass for crash simulation

In this paper, we present a numerical technique to simulate the crash behaviour of laminated safety glass via finite elements. As the main aspect of this work, we consider two coincided elements: a shell element for glass and a membrane element for the hyperelastic PVB-interlayer. We give an overview of hyperelastic models, which are used in crash simulations and investigate the material laws by Blatz–Ko, Mooney–Rivlin and Ogden. The obtained stress–strain curves are fitted by experimental results of the interlayer. For a comparison, we use an one-material-model with piecewise linear plasticity and a laminated glass model assigning material properties to the integration points. As practical applications, we simulate an impact of a sphere into a glass plate and investigate the behaviour of a windscreen during a roof crash.     

Examining the relative effectiveness of different message framing strategies for child passenger safety: Recommendations for increased comprehension and compliance

Background

Age-appropriate child restraints and rear seating dramatically reduce injury in vehicle crashes. Yet parents and caregivers struggle to comply with child passenger safety (CPS) recommendations, and frequently make mistakes when choosing and installing restraints. The purpose of this research was to evaluate various methods of framing CPS recommendations, and to examine the relative effectiveness on parents’ knowledge, attitudes, and behavioral intentions related to best practices and proper use of child restraints. Emphasis framing is a persuasion technique that involves placing focus on specific aspects of the content in order to encourage or discourage certain interpretations of the content.

Method

A 5 (flyer group) X 2 (time) randomized experiment was conducted in which 300 parent participants answered a pre-survey, viewed one of four flyer versions or a no-education control version, and completed a post-survey. Surveys measured CPS knowledge, attitudes, perceptions of efficacy and risk, and behavioral intentions. The four flyers compared in this study all communicated the same CPS recommendations, but several versions were tested which each employed a different emphasis frame: (1) recommendations organized by the natural progression of seat types; (2) recommendations which focused on avoiding premature graduation; (3) recommendations which explained the risk-reduction rationale behind the information given; or (4) recommendations which were organized by age. In a fifth no-education (control) condition, participants viewed marketing materials.

Results

Analyses of covariance and pairwise comparisons indicated the risk-reduction rationale flyer outperformed other flyers for many subscales, and significantly differed from no-education control for the most subscales, including restraint selection, back seat knowledge, rear-facing knowledge and attitudes, total efficacy, overall attitudes, and stated intentions.

Conclusions

This research provides insight for increasing caregiver understanding and compliance with CPS information. Recommendations for the field include communicating the rationale behind the information given, using behavior-based directives in headers, avoiding age-based headers, and incorporating back-seat positioning directives throughout.     

乘用车-载货汽车追尾碰撞相容性结构优化设计

对一种已获得专利的新型货车后防护结构进行碰撞相容性优化设计,建立了该结构的乘用车-货车追尾碰撞有限元模型,并通过实车碰撞试验验证了模型有效性。为提高碰撞相容性,制定了防护架最大的吸能和乘用车前部最小的变形量两个优化目标函数,并设计了优化设计参数变量及其变化范围,采用正交化试验方法对16组参数进行了有限元仿真,并对优化目标的影响因素进行了显著性分析,最后,对得到最优的设计方案进行了实车碰撞试验     

Sample-size guidelines for recalibrating crash prediction models: Recommendations for the highway safety manual

The Highway Safety Manual (HSM) prediction models are fitted and validated based on crash data collected from a selected number of states in the United States. Therefore, for a jurisdiction to be able to fully benefit from applying these models, it is necessary to calibrate or recalibrate them to local conditions. The first edition of the HSM recommends calibrating the models using a one-size-fits-all sample-size of 30–50 locations with total of at least 100 crashes per year. However, the HSM recommendation is not fully supported by documented studies. The objectives of this paper are consequently: (1) to examine the required sample size based on the characteristics of the data that will be used for the calibration or recalibration process; and, (2) propose revised guidelines. The objectives were accomplished using simulation runs for different scenarios that characterized the sample mean and variance of the data. The simulation results indicate that as the ratio of the standard deviation to the mean (i.e., coefficient of variation) of the crash data increases, a larger sample-size is warranted to fulfill certain levels of accuracy. Taking this observation into account, sample-size guidelines were prepared based on the coefficient of variation of the crash data that are needed for the calibration process. The guidelines were then successfully applied to the two observed datasets. The proposed guidelines can be used for all facility types and both for segment and intersection prediction models.     

Driver seat belt use indicates decreased risk for child passengers in a motor vehicle crash

Study objective

We examined the association between driver restraint use and child emergency department (ED) evaluation following a motor vehicle crash (MVC).

Methods

This cohort study included child passengers aged 0-12 years riding with an adult driver aged 21 years or older involved in a MVC in Utah from 1999 to 2004. The 6 years of Utah MVC records were probabilistically linked to statewide Utah ED records. We estimated the relative risk of ED evaluation following a MVC for children riding with restrained versus unrestrained drivers. Generalized estimating equations were used to calculate relative risks adjusted for child, driver, and crash characteristics.

Results

Six percent (6%) of children riding with restrained adult drivers were evaluated in the ED compared to twenty-two percent (22%) of children riding with unrestrained adult drivers following a MVC (relative risk 0.29, 95% confidence interval 0.26-0.32). After adjusting for child, vehicle, and crash characteristics, the relative risk of child ED evaluation associated with driver restraint remained significant (relative risk 0.82, 95% confidence interval 0.72-0.94). Driver restraint use was associated with child restraint use, less alcohol/drug involvement, and lower relative risk of severe collision types (head-on, rollover).

Conclusions

Driver seat belt use is associated with decreased risk of ED evaluation for child passengers in the event of a MVC.     

Simulation of crash tests for high containment levels of road safety barriers

This paper presents the results of computer simulations of road safety barrier behaviour under vehicle crash conditions for high containment levels as mandated by the European standard EN 1317. Simulations were performed with the explicit finite element code LS-DYNA, running on a multiprocessor computational platform. A very good agreement of simulation and real crash tests results was observed, which in turn justifies the use of computer simulations in the process of development and certification of road safety barriers.     

Differences in passenger car and large truck involved crash frequencies at urban signalized intersections: An exploratory analysis

The influence of intersection features on safety has been examined extensively because intersections experience a relatively large proportion of motor vehicle conflicts and crashes. Although there are distinct differences between passenger cars and large trucks-size, operating characteristics, dimensions, and weight-modeling crash counts across vehicle types is rarely addressed. This paper develops and presents a multivariate regression model of crash frequencies by collision vehicle type using crash data for urban signalized intersections in Tennessee. In addition, the performance of univariate Poisson-lognormal (UVPLN), multivariate Poisson (MVP), and multivariate Poisson-lognormal (MVPLN) regression models in establishing the relationship between crashes, traffic factors, and geometric design of roadway intersections is investigated. Bayesian methods are used to estimate the unknown parameters of these models. The evaluation results suggest that the MVPLN model possesses most of the desirable statistical properties in developing the relationships. Compared to the UVPLN and MVP models, the MVPLN model better identifies significant factors and predicts crash frequencies. The findings suggest that traffic volume, truck percentage, lighting condition, and intersection angle significantly affect intersection safety. Important differences in car, car–truck, and truck crash frequencies with respect to various risk factors were found to exist between models. The paper provides some new or more comprehensive observations that have not been covered in previous studies.     

Finite mixture modeling approach for developing crash modification factors in highway safety analysis

This study aimed to investigate the relative performance of two models (negative binomial (NB) model and two-component finite mixture of negative binomial models (FMNB-2)) in terms of developing crash modification factors (CMFs). Crash data on rural multilane divided highways in California and Texas were modeled with the two models, and crash modification functions (CMFunctions) were derived. The resultant CMFunction estimated from the FMNB-2 model showed several good properties over that from the NB model. First, the safety effect of a covariate was better reflected by the CMFunction developed using the FMNB-2 model, since the model takes into account the differential responsiveness of crash frequency to the covariate. Second, the CMFunction derived from the FMNB-2 model is able to capture nonlinear relationships between covariate and safety. Finally, following the same concept as those for NB models, the combined CMFs of multiple treatments were estimated using the FMNB-2 model. The results indicated that they are not the simple multiplicative of single ones (i.e., their safety effects are not independent under FMNB-2 models). Adjustment Factors (AFs) were then developed. It is revealed that current Highway Safety Manual’s method could over- or under-estimate the combined CMFs under particular combination of covariates. Safety analysts are encouraged to consider using the FMNB-2 models for developing CMFs and AFs.     

铁路列车真空厕所系统设计

针对我国目前使用的铁路直接排放式厕所不雅观不文明、污染环境、浪费水等问题,设计了真空厕所系统.真空厕所基于真空运输理论,利用真空泵抽取真空室、纳污罐和输送管道内的空气,降低其中的大气压力,一般在0.03MPa～0.05MPa范围内,接入便器,利用界面阀控制便器与管道通断,将粪便吸入至纳污罐,实现了粪便污物的抽吸.由于其冲洗水少,不易堵塞管路,整套系统密封,有效控制臭气外漏,不易污染环境,故其是新一代环保产品.研究了铁路列车真空厕所系统工作原理和工作过程,设计了其控制电路.     

Rear seat safety: Variation in protection by occupant,crash and vehicle characteristics

Objectives

Current information on the safety of rear row occupants of all ages is needed to inform further advances in rear seat restraint system design and testing. The objectives of this study were to describe characteristics of occupants in the front and rear rows of model year 2000 and newer vehicles involved in crashes and determine the risk of serious injury for restrained crash-involved rear row occupants and the relative risk of fatal injury for restrained rear row vs. front passenger seat occupants by age group, impact direction, and vehicle model year.

Method

Data from the National Automotive Sampling System Crashworthiness Data System (NASS-CDS) and Fatality Analysis Reporting System (FARS) were queried for all crashes during 2007–2012 involving model year 2000 and newer passenger vehicles. Data from NASS-CDS were used to describe characteristics of occupants in the front and rear rows and to determine the risk of serious injury (AIS 3+) for restrained rear row occupants by occupant age, vehicle model year, and impact direction. Using a combined data set containing data on fatalities from FARS and estimates of the total population of occupants in crashes from NASS-CDS, logistic regression modeling was used to compute the relative risk (RR) of death for restrained occupants in the rear vs. front passenger seat by occupant age, impact direction, and vehicle model year.

Results

Among all vehicle occupants in tow-away crashes during 2007–2012, 12.3% were in the rear row where the overall risk of serious injury was 1.3%. Among restrained rear row occupants, the risk of serious injury varied by occupant age, with older adults at the highest risk of serious injury (2.9%); by impact direction, with rollover crashes associated with the highest risk (1.5%); and by vehicle model year, with model year 2007 and newer vehicles having the lowest risk of serious injury (0.3%). Relative risk of death was lower for restrained children up to age 8 in the rear compared with passengers in the right front seat (RR = 0.27, 95% CI 0.12–0.58 for 0–3 years, RR = 0.55, 95% CI 0.30–0.98 for 4–8 years) but was higher for restrained 9–12-year-old children (RR = 1.83, 95% CI 1.18–2.84). There was no evidence for a difference in risk of death in the rear vs. front seat for occupants ages 13-54, but there was some evidence for an increased relative risk of death for adults age 55 and older in the rear vs. passengers in the right front seat (RR = 1.41, 95% CI 0.94–2.13), though we could not exclude the possibility of no difference. After controlling for occupant age and gender, the relative risk of death for restrained rear row occupants was significantly higher than that of front seat occupants in model year 2007 and newer vehicles and significantly higher in rear and right side impact crashes.

Conclusions

Results of this study extend prior research on the relative safety of the rear seat compared with the front by examining a more contemporary fleet of vehicles. The rear row is primarily occupied by children and adolescents, but the variable relative risk of death in the rear compared with the front seat for occupants of different age groups highlights the challenges in providing optimal protection to a wide range of rear seat occupants. Findings of an elevated risk of death for rear row occupants, as compared with front row passengers, in the newest model year vehicles provides further evidence that rear seat safety is not keeping pace with advances in the front seat.     

The crash reduction effectiveness of a network-wide traffic police deployment system

Random Road Watch (RRW) is a traffic policing program in operation in Queensland, Australia. It differs from conventional traffic policing in that an explicit resource management technique is used which randomly schedules low levels of police enforcement in a manner intended to provide long-term, widespread coverage of a road network and hence maximise road safety benefits. Implementation of the program studied in Queensland covered 55% of total crashes within the state. This study aimed to measure the crash effects of the RRW program in Queensland. A quasi-experimental study design was used for the evaluation incorporating Poisson regression statistical analysis techniques. Analysis of the effects of the Queensland RRW program on crash frequency has shown the program to be effective overall. Estimated program effects were largest on fatal crashes, with an estimated reduction of 31%. Estimated aggregate program crash effects reduced with crash severity and increased with time after program introduction. Crash reductions in the third year after program introduction translated into savings, at state level, of some 12% of the state's crashes of all severities and some 15% of the state's fatal road crashes. Overall, the program produced a significant 11% reduction in total crashes in areas outside of metropolitan Brisbane. The opportunity-cost benefit/cost ratio for the program was estimated to be 55:1.     

Validating crash locations for quantitative spatial analysis: a GIS-based approach

In this paper, the spatial variables of the crash database in Hong Kong from 1993 to 2004 are validated. The proposed spatial data validation system makes use of three databases (the crash, road network and district board databases) and relies on GIS to carry out most of the validation steps so that the human resource required for manually checking the accuracy of the spatial data can be enormously reduced. With the GIS-based spatial data validation system, it was found that about 65-80% of the police crash records from 1993 to 2004 had correct road names and district board information. In 2004, the police crash database contained about 12.7% mistakes for road names and 9.7% mistakes for district boards. The situation was broadly comparable to the United Kingdom. However, the results also suggest that safety researchers should carefully validate spatial data in the crash database before scientific analysis.     

MChip: a tool for influenza surveillance

The design and characterization of a low-density microarray for subtyping influenza A is presented. The microarray consisted of 15 distinct oligonucleotides designed to target only the matrix gene segment of influenza A. An artificial neural network was utilized to automate microarray image interpretation. The neural network was trained to recognize fluorescence image patterns for 68 known influenza viruses and subsequently used to identify 53 unknowns in a blind study that included 39 human patient samples and 14 negative control samples. The assay exhibited a clinical sensitivity of 95% and clinical specificity of 92%.     

Cabin safety and emergency evacuation: passenger experience of flight CI-120 accident

Aircraft evacuation effectiveness is a critical but challenging issue in the civil aviation industry. This paper explores the cabin safety perceptions of passengers from their emergency evacuation experiences in an actual aviation accident. A questionnaire survey and in-depth interviews were conducted with China Airlines flight CI-120 passengers. The qualitative and quantitative results provide insights into passengers’ views of cabin safety. The in-depth interview results show that passenger safety education requires more instructions about the use of emergency equipment. The data from the passenger perception questionnaire were analyzed using the factor analysis method; the findings indicate that crew assistance and emergency procedures are the most important factors. The results are likely to be of value to the aviation industry when taking into account passenger perceptions in implementing safety programs.     

Robust design of an interior hard trim to improve occupant safety in a vehicle crash

Head injury ranks among the top contributors in automobile accidents. Consequently, although styling is treated important, safety of occupants in a crash receives preemptive priority in the design of automotive interior components. Additionally, the Federal Motor Vehicle Safety Standard (FMVSS) 201 has laid down certain requirements to be fulfilled by automobile manufacturers for producing a safe vehicle. One of the requirements stipulate dummy equivalent of the Head Injury Criteria, i.e. HIC(d) value for the interior components of a vehicle to be below 1000 under certain stated conditions. In this paper, we provide a robust design approach to achieve the requirements for one such interior component, viz. an interior hard trim that covers the pillar closest to the driver's head on the left-hand side of the vehicle.     

Coupling analysis of passenger and train flows for a large-scale urban rail transit system

Coupling analysis of passenger and train flows is an important approach in evaluating and optimizing the operation efficiency of large-scale urban rail transit (URT) systems. This study proposes a passenger–train interaction simulation approach to determine the coupling relationship between passenger and train flows. On the bases of time-varying origin–destination demand, train timetable, and network topology, the proposed approach can restore passenger behaviors in URT systems. Upstream priority, queuing process with first-in-first-serve principle, and capacity constraints are considered in the proposed simulation mechanism. This approach can also obtain each passenger’s complete travel chain, which can be used to analyze (including but not limited to) various indicators discussed in this research to effectively support train schedule optimization and capacity evaluation for urban rail managers. Lastly, the proposed model and its potential application are demonstrated via numerical experiments using real-world data from the Beijing URT system (i.e., rail network with the world’s highest passenger ridership).