Improvement of driver active interventions during automated driving by displaying trajectory pointers—A driving simulator study

Abstract

Objective: The handover of vehicle control from automated to manual operation is a critical aspect of interaction between drivers and automated driving systems (ADS). In some cases, it is possible that the ADS may fail to detect an object. In this event, the driver must be aware of the situation and resume control of the vehicle without assistance from the system. Consequently, the driver must fulfill the following 2 main roles while driving: (1) monitor the vehicle trajectory and surrounding traffic environment and (2) actively take over vehicle control if the driver identifies a potential issue along the trajectory. An effective human–machine interface (HMI) is required that enables the driver to fulfill these roles. This article proposes an HMI that constantly indicates the future position of the vehicle.

Methods: This research used the Toyota Dynamic Driving Simulator to evaluate the effect of the proposed HMI and compares the proposed HMI with an HMI that notifies the driver when the vehicle trajectory changes. A total of 48 test subjects were divided into 2 groups of 24: One group used the HMI that constantly indicated the future position of the vehicle and the other group used the HMI that provided information when the vehicle trajectory changed.

The following instructions were given to the test subjects: (1) to not hold the steering wheel and to allow the vehicle to drive itself, (2) to constantly monitor the surrounding traffic environment because the functions of the ADS are limited, and (3) to take over driving if necessary.

The driving simulator experiments were composed of an initial 10-min acclimatization period and a 10-min evaluation period. Approximately 10?min after the start of the evaluation period, a scenario occurred in which the ADS failed to detect an object on the vehicle trajectory, potentially resulting in a collision if the driver did not actively take over control and manually avoid the object.

Results: The collision avoidance rate of the HMI that constantly indicated the future position of the vehicle was higher than that of the HMI that notified the driver of trajectory changes, χ² = 6.38, P < .05. The steering wheel hands-on and steering override timings were also faster with the proposed HMI (t test; P < .05).

Conclusions: This research confirmed that constantly indicating the position of the vehicle several seconds in the future facilitates active driver intervention when an ADS is in operation.     

基于驾驶模拟的自动驾驶接管行为研究

为探索有条件自动驾驶对非驾驶相关任务的允准边界,基于实车驾驶模拟器,设计自动驾驶接管试验典型场景,招募30名被试者开展驾驶模拟试验;要求驾驶人执行3种分心形式的驾驶次任务,系统发出接管请求提示后,驾驶人接管车辆控制权以避免险情发生,并分析驾驶人接管反应时间、驾驶负荷以及驾驶绩效等相关数据.结果表明:驾驶次任务涉及的分心...     

Test procedure for evaluating the human–machine interface of vehicles with automated driving systems

Abstract

Objective: The human–machine interface (HMI) is a crucial part of every automated driving system (ADS). In the near future, it is likely that—depending on the operational design domain (ODD)—different levels of automation will be available within the same vehicle. The capabilities of a given automation level as well as the operator’s responsibilities must be communicated in an appropriate way. To date, however, there are no agreed-upon evaluation methods that can be used by human factors practitioners as well as researchers to test this.

Methods: We developed an iterative test procedure that can be applied during the product development cycle of ADS. The test procedure is specifically designed to evaluate whether minimum requirements as proposed in NHTSA’s automated vehicle policy are met.

Results: The proposed evaluation protocol includes (a) a method to identify relevant use cases for testing on the basis of all theoretically possible steady states and mode transitions of a given ADS; (b) an expert-based heuristic assessment to evaluate whether the HMI complies with applicable norms, standards, and best practices; and (c) an empirical evaluation of ADS HMIs using a standardized design for user studies and performance metrics.

Conclusions: Each can be used as a stand-alone method or in combination to generate objective, reliable, and valid evaluations of HMIs, focusing on whether they meet minimum requirements. However, we also emphasize that other evaluation aspects such as controllability, misuse, and acceptance are not within the scope of the evaluation protocol.     

Functional decomposition—A contribution to overcome the parameter space explosion during validation of highly automated driving

Abstract

Objective: Particular testing by functional decomposition of the automated driving function can potentially contribute to reducing the effort of validating highly automated driving functions. In this study, the required size of test suites for scenario-based testing and the potential to reduce it by functional decomposition are quantified for the first time.

Methods: The required size of test suites for scenario-based approval of a so-called Autobahn-Chauffeur (SAE Level 3) is analyzed for an exemplary set of scenarios. Based on studies of data from failure analyses in other domains, the possible range for the required test coverage is narrowed down and suitable discretization steps, as well as ranges for the influence parameters, are assumed. Based on those assumptions, the size of the test suites for testing the complete system is quantified. The effects that lead to a reduction in the parameter space for particular testing of the decomposed driving function are analyzed and the potential to reduce the validation effort is estimated by comparing the resulting test suite sizes for both methods.

Results: The combination of all effects leads to a reduction in the test suites’ size by a factor between 20 and 130, depending on the required test coverage. This means that the size of the required test suite can be reduced by 95–99% by particular testing compared to scenario-based testing of the complete system.

Conclusions: The reduction potential is a valuable contribution to overcome the parameter space explosion during the validation of highly automated driving. However, this study is based on assumptions and only a small set of exemplary scenarios. Thus, the findings have to be validated in further studies.     

Effects of mobile phone use on driving performance in a multiresource workload scenario

Objective: This study explores the influence of mobile phone secondary tasks on driving from the perspective of visual, auditory, cognitive, and psychomotor (VACP) multiple resource theory, and it is anticipated to benefit the human-centered design of mobile phone use while driving.

Methods: The present study investigated 6 typical phone use scenarios while driving and analyzed the effects of phone use distractions on driving performance. Thirty-six participants were recruited to participate in this experiment. We abandoned traditional secondary tasks such as conversations or dialing, in which cognitive resources can become interference. Instead, we adopted an arrow secondary task and an n-back delayed digit recall task.

Results: The results show that all mobile phone use scenarios have a significant influence on driving performance, especially on lateral vehicle control. The visual plus psychomotor resource occupation scenario demonstrated the greatest deterioration of driving performance, and there was a significant deterioration of driving speed and steering wheel angle once the psychomotor resource was occupied.

Conclusions: Phone use distraction leads to visual, cognitive, and/or motor resource functional limitations and thus causes lane violations and traffic accidents.     

视觉记忆型次任务对驾驶绩效及安全的影响

为研究视觉记忆型次任务对驾驶绩效及安全的影响,采用对未知内容的记忆任务和对已知内容的再认任务分别表征工作记忆和长时记忆过程,构建多组不同难度的次任务,基于标准换道试验环境LCT进行双任务研究。提取并分析驾驶人执行不同任务时车道保持、换道控制等指标的差异以及次任务绩效,基于主客观数据构建综合评判模型。结果表明:双任务驾驶条件下,车辆平均路径偏差、方向盘平均转向角、车道偏移次数指标增大,正确换道比例减小,感知负荷增大,总绩效下降。困难工作记忆组与简单工作记忆组相比,随着任务难度增大,换道控制绩效下降,感知负荷增大,总绩效下降36.1%;困难再认组与工作记忆组相比,车道保持绩效、换道控制绩效提高,感知负荷下降,总绩效提高50%;简单再认组与工作记忆组相比,总绩效变化不大;困难工作记忆组综合绩效最低。上述结果说明:随着次任务难度增大,总绩效下降,但将对未知内容的工作记忆过程转化为对已知内容的再认过程时,总绩效明显提升,这一特点在任务难度较大时更为显著。     

Structural equation model analysis for the evaluation of overall driving performance: A driving simulator study focusing on driver distraction

Objective: The present research relies on 2 main objectives. The first is to investigate whether latent model analysis through a structural equation model can be implemented on driving simulator data in order to define an unobserved driving performance variable. Subsequently, the second objective is to investigate and quantify the effect of several risk factors including distraction sources, driver characteristics, and road and traffic environment on the overall driving performance and not in independent driving performance measures.

Methods: For the scope of the present research, 95 participants from all age groups were asked to drive under different types of distraction (conversation with passenger, cell phone use) in urban and rural road environments with low and high traffic volume in a driving simulator experiment. Then, in the framework of the statistical analysis, a correlation table is presented investigating any of a broad class of statistical relationships between driving simulator measures and a structural equation model is developed in which overall driving performance is estimated as a latent variable based on several individual driving simulator measures.

Results: Results confirm the suitability of the structural equation model and indicate that the selection of the specific performance measures that define overall performance should be guided by a rule of representativeness between the selected variables. Moreover, results indicate that conversation with the passenger was not found to have a statistically significant effect, indicating that drivers do not change their performance while conversing with a passenger compared to undistracted driving. On the other hand, results support the hypothesis that cell phone use has a negative effect on driving performance. Furthermore, regarding driver characteristics, age, gender, and experience all have a significant effect on driving performance, indicating that driver-related characteristics play the most crucial role in overall driving performance.

Conclusions: The findings of this study allow a new approach to the investigation of driving behavior in driving simulator experiments and in general. By the successful implementation of the structural equation model, driving behavior can be assessed in terms of overall performance and not through individual performance measures, which allows an important scientific step forward from piecemeal analyses to a sound combined analysis of the interrelationship between several risk factors and overall driving performance.     

Effect prediction of time-gaps for adaptive cruise control (ACC) and in-vehicle tasks on bus driver performance

Researchers have devoted a great deal of attention to the effects of driver assist systems on driver performance. This article describes a modeling approach to simulate the effects of time-gaps for adaptive cruise control (ACC) and manual in-vehicle tasks on bus-driver performance. A concept model was built with the knowledge of modularization, parameterization, and parallel processing. By running the model, the predictions for the effects of five levels of time-gaps and two types of in-vehicle tasks were collected in three measures: (1) mean gap, (2) minimum gap, and (3) collision rate. The model performed well in prediction, especially when driving with in-vehicle tasks. Predictions from the model were validated by the experiment with a verified fixed-base bus-driving simulator, used in the authors’ previous studies. Throughout the modeling approach, this research provides a theoretical and accurate way to assess effects of time-gaps and vehicle-equipped interfaces. In follow-up research, the authors will apply this approach to evaluate other driving assist systems (e.g. collision warning systems and navigation systems) to create a customized software kit.     

The effects of minimum legal drinking age 21 laws on alcohol-related driving in the United States

Objective

To examine trends in alcohol consumption and alcohol-related crashes among people younger than 21 in the United States and to review evidence on the effects of minimum legal drinking age (MLDA) laws.

Methods

Trends in alcohol-related crashes and alcohol consumption among young people were examined, and studies on the effects of lowering and raising the drinking age were reviewed.

Results

MLDA laws underwent many changes during the 20th century in the United States. Since July 1988, the MLDA has been 21 in all 50 states and the District of Columbia. Surveys tracking alcohol consumption among high school students and young adults found that drinking declined since the late 1970 s, and most of the decline occurred by the early 1990 s. These were the years when states were establishing, or reinstating, a MLDA-21. Among fatally injured drivers ages 16-20, the percentage with positive BACs declined from 61% in 1982 to 31% in 1995, a bigger decline than for older age groups; declines occurred among the ages directly affected by raising MLDAs (ages 18-20) and among young teenagers not directly affected (ages 16-17). Almost all studies designed specifically to gauge the effects of drinking age changes show MLDAs of 21 reduce drinking, problematic drinking, drinking and driving, and alcohol-related crashes among young people. Yet many underage people still drink, many drink and drive, and alcohol remains an important risk factor in serious crashes of young drivers, especially as they progress through the teenage years. Stepped-up enforcement of MLDA and drinking and driving laws can reduce underage drinking. Recent efforts to lower MLDAs to 18 and issue licenses to drink upon completion of alcohol education have gained local and national media attention. There is no evidence that alcohol education can even partially replace the effect of MLDA-21.

Conclusions

The cause and effect relationship between MLDAs of 21 and reductions in highway crashes is clear. Initiatives to lower the drinking age to 18 ignore the demonstrated public health benefits of MLDAs of 21.

Impact on Industry

Lowering the drinking age to 18 will increase highway crash deaths among young people.     

A review of driving risks and impairments associated with attention-deficit/hyperactivity disorder and the effects of stimulant medication on driving performance

INTRODUCTION: Attention-Deficit/Hyperactivity Disorder (ADHD) may interfere with driving competence, predisposing those with the disorder to impaired driving performance and greater risk for adverse driving outcomes. Effective treatment may minimize the risk in those with ADHD. METHOD: We reviewed the scientific literature on driving risks and impairments associated with ADHD and the effects of stimulants on driving performance. Several lines of evidence were considered, including longitudinal studies and community-derived sample studies. The present review is based on a weekly review (by the first author) of all journals in the behavioral and social sciences indexed in the publication Current Contents spanning the past 15 years, as well as a search of the reference section of all studies found that pertained to driving risks associated with ADHD or to the treatment of ADHD as it relates to driving difficulties. RESULTS: The review of the scientific literature demonstrated well-documented driving risks and impairments associated with ADHD and the positive effects of stimulant medications on driving performance. CONCLUSIONS: Clinicians should educate patients/caregivers about the increased risk of adverse outcomes among untreated individuals with ADHD and the role of medication in potentially improving driving performance. IMPACT ON INDUSTRY: Owing to the significantly higher risk of adverse driving outcomes, the use of stimulant medications to treat people with ADHD who drive may reduce such safety risks.     

矿用耐崩风筒在掘进迎头的性能研究

进行矿用风筒现场应用的实际性能实验,可以全面直观的检验风筒的通风性能和抗炮崩能力,对于风筒产品的质量考核和掘进迎头的通风安全具有重要意义。本文针对新型Kevlar耐崩风筒,研究矿用风筒性能的判定指标和检测方法,并在全岩巷道掘进工作面、半煤岩巷道掘进工作面以及全煤巷道掘进工作面进行Kevlar风筒现场应用实验,与我国目前矿山普遍使用的玻纤布风筒的现场应用进行对比,从物理机械强度、通风性能以及掘进成本等方面分析Kevlar耐崩风筒的实际性能,研究Kevlar风筒替代玻纤布风筒的可行性。经过现场应用的实验和检验,Kevlar风筒比目前国内应用的玻纤布风筒性能优越,具有经济、安全、耐用、便捷的特点。     

Experimental evidence for the effects of task repetitiveness on mental strain and objective work performance

People frequently have to work in high repetitive jobs. Previous research has focused exclusively on the effects of task repetitiveness on well‐being, while neglecting effects on work performance. In the present study, we aimed to fill this void by conducting two workplace simulations with experimental manipulations of task repetitiveness. Participants worked for about 5 hours at either a computer workstation, compiling computer hardware packages according to customer requests (Experiment 1, N = 160), or at an assembly line, piecing together equipment sets for furniture (Experiment 2, N = 213). Both experiments provide consistent evidence that high repetitiveness has a detrimental effect on well‐being, whereas work performance increases under conditions of high repetitiveness. On a practical level, our study hence shows that high task repetitiveness is a double‐edged sword for both employees and organizations. On a conceptual level, our findings emphasize the necessity to account for both mental strain and work performance when examining the effects of task repetitiveness. Copyright © 2014 John Wiley & Sons, Ltd.     

When leaders are forced to stay: The indirect effects of leaders' reluctant staying on subordinates' performance

Leaders who desire to leave the current organization are sometimes forced to stay. The leadership behaviors of these leaders are underexplored in the current literature. Building on proximal withdrawal states theory, this study examines two pathways through which leaders' reluctant staying mindset (i.e., desire but are unable to quit) relates to their subordinates' task performance and organizational citizenship behaviors (OCB). One pathway proposes increased laissez-faire leadership behaviors due to leaders' lower intrinsic motivation; the second pathway proposes increased delegation behaviors due to leaders' higher extrinsic motivation. Using three-wave data collected from 100 leaders and 313 subordinates, we found that leaders' reluctant staying was indirectly and negatively associated with subordinates' task performance and OCB through leaders' lower perceptions of task significance and higher laissez-faire leadership behaviors. At the same time, leaders' reluctant staying increased their bottom-line mentality and delegation behaviors, but the indirect effects on subordinates' performance outcomes were not significant. We discuss the implications of our findings for theory, practices, and future research regarding how to manage leaders who stay reluctantly in the organization.     

特厚煤层沿空掘巷合理留设小煤柱的试验研究

为减少煤柱损失量,改善巷道维护现状和提高煤炭回采率,以庞庞塔煤矿10#特厚煤层为工程背景,采用理论计算、FLAC3D数值模拟和现场观测方法对该矿特厚煤层综放沿空掘巷留设的小煤柱宽度进行了研究。计算表明:小煤柱合理留设宽度为7.7～9 m。以小煤柱理论计算为基础,结合工作面端头侧的应力与煤柱侧向支承压力分布特征,提出了4种小煤柱留宽方案,通过数值模拟对比分析不同留宽煤柱在掘巷和回采阶段的围岩应力和受载变形情况,最终得出小煤柱合理留宽为9 m。工程实践表明:按9 m留设区段煤柱,并采用合理支护设计,巷道顶底板及两帮变形量较小,煤柱稳定性良好,留宽方案满足生产使用要求。     

The interactive effects of conscientiousness,openness to experience,and political skill on job performance in complex jobs: The importance of context

Caveats concerning the ability of personality to predict job performance have been raised because of seemingly modest criterion‐related validity. The goal of the present research was to test whether narrowing the context via the type of job (i.e., jobs with complex task demands) and adding a social skill‐related moderator (i.e., political skill) would improve performance prediction. Further, along with political skill, the broad factor of personality demonstrated in prior research to have the strongest criterion validity (i.e., conscientiousness) was joined with a narrow construct closely related to openness to experience (i.e., learning approach) in a three‐way interactive prediction of supervisor‐rated task performance. With the employee–supervisor dyads among professionals, but not with the control group of non‐professional employees, task performance was predicted by the three‐way interaction, such that those high on all three received the highest performance ratings. Implications, strengths and limitations, and directions for future research are discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

掘进面多级气相压裂卸压抽采防突研究

为解决煤层赋存条件复杂、煤体渗透率低、部分区域突出易发性高等问题,提出运用多级气相压裂的方案在阳泉矿区新元矿31004工作面辅助回风巷与进风巷进行压裂试验,以考察其卸压增透效果;在试验巷道的不同区段实施单孔压裂和双孔压裂,并采用"压裂抽采"和"压后即掘"2种工作循环方式进行试验;基于对多项抽采参数的实测结果,从多角度评...     

Representativity and univocity of traffic signs and their effect on trajectory movement in a driving simulation task: Warning signs

Objective: The effect of traffic signs on the behavior of drivers is not completely understood. Knowing about how humans process the meaning of signs (not just by learning but instinctively) will improve reaction time and decision making when traveling. The economic, social, and psychological consequences of car accidents are well known.

Methods: This study sounds out which traffic signs are more ergonomic for participants, from a cognitive point of view, and determines, at the same time, their effect in participants' movement trajectories in a driving simulation task.

Results: Results point out that the signs least representative of their meaning produce a greater deviation from the center of the road than the most representative ones.

Conclusions: This study encourages both an in-depth analysis of the effect on movement of roadside signs and the study of how this effect can be modified by the context in which these signs are presented (with the aim to move the research closer to and analyze the data in real contexts). The goal is to achieve clarity of meaning and lack of counterproductive effects on the trajectory of representative signs (those that provoke fewer mistakes in the decision task).     

我国涉水旅游安全事故的时空分布及成因研究*

为探究我国涉水旅游安全事故的时空分布特征及事故成因机制,提升旅游目的地安全管理水平。以2010—2018年我国旅行社责任险平台的1 752起涉水旅游安全事故保险案例为数据源,利用社会网络分析方法,并结合Ucinet可视化分析技术构建事故时空分布模型及事故成因模型。结果表明:在时空分布规律上,我国涉水旅游安全事故具有较强的时间导向性和空间异质性;在事故成因规律上,游览环境因素和游客自身因素是导致事故发生的主要原因,同时不同影响因素之间具有较强的关联性。研究结果有助于深化旅游者及安全管理人员对涉水旅游安全风险认知,为相关旅游目的地安全管理工作提供理论依据。     

Modeling the effects of production pressure on safety performance in construction projects using system dynamics

Introduction: Construction incidents occur due to system failures, not due to a single factor such as unsafe behavior or condition. Therefore, construction safety should be investigated using a systematic view capable of illustrating the complex nature of incidents. Construction projects are also often behind their planned schedule and suffer from various pressures caused by contractual deadlines or clients. Previous studies demonstrated that such pressures negatively affect safety performance; however, the process of how production pressure influences safety performance is not fully investigated. Method: The present research aimed to understand the feedback mechanism of how production pressure interactively affects safety performance and safety-related managerial components in a construction project. Ground theory method (GTM) is used to create a conceptual causal loop diagram that shows the relationship between incident rate and other variables such as labor hour, actual and planned progress, safety climate, rework, and safety training. Moreover, a power plant construction project was used as a case study to practically investigate the conceptual model; a case study is employed to build a System Dynamics (SD) model. The simulation model was then validated using behavior reproduction and sensitivity analysis. Results: The results of the inequality statistics show that the simulation model can be used to forecast trends in the incident rate.     

We're all in this together…except for you: The effects of workload,performance feedback,and racial distance on helping behavior in teams

We draw from social categorization theory and the actor–observer hypothesis to extend previous research regarding receiving high levels of help from team members. Specifically, we explore how a team member's performance feedback on how they handled a disproportionately heavy share of the team's workload and how their racial distance from the rest of their teammates affect the amount of helping that person receives from their teammates. Results from a laboratory study in which 79 teams worked on a computerized, decision‐making task demonstrated a three‐way interaction between workload, performance feedback, and the racial distance between the feedback recipient and the rest of their teammates. Racially distant negative feedback recipients who had a disproportionately heavy share of their team's workload received less help from teammates than their racially similar counterparts. Copyright © 2012 John Wiley & Sons, Ltd.