Are situation awareness and decision-making in driving totally conscious processes? Results of a hazard prediction task

Detecting danger in the driving environment is an indispensable task to guarantee safety which depends on the driver’s ability to predict upcoming hazards. But does correct prediction lead to an appropriate response? This study advances hazard perception research by investigating the link between successful prediction and response selection. Three groups of drivers (learners, novices and experienced drivers) were recruited, with novice and experienced drivers further split into offender and non-offender groups. Specifically, this works aims to develop an improved Spanish Hazard Prediction Test and to explore the differences in Situation Awareness, (SA: perception, comprehension and prediction) and Decision-Making (DM) among learners, younger inexperienced and experienced drivers and between driving offenders and non-offenders. The contribution of the current work is not only theoretical; the Hazard Prediction Test is also a valid way to test Hazard Perception. The test, as well as being useful as part of the test for a driving license, could also serve a purpose in the renewal of licenses after a ban or as a way of training drivers. A sample of 121 participants watched a series of driving video clips that ended with a sudden occlusion prior to a hazard. They then answered questions to assess their SA (“What is the hazard?” “Where is it located?” “What happens next?”) and DM (“What would you do in this situation?”). This alternative to the Hazard Perception Test demonstrates a satisfactory internal consistency (Alpha = 0.750), with eleven videos achieving discrimination indices above 0.30. Learners performed significantly worse than experienced drivers when required to identify and locate the hazard. Interestingly, drivers were more accurate in answering the DM question than questions regarding SA, suggesting that drivers can choose an appropriate response manoeuvre without a totally conscious knowledge of the exact hazard.     

危险类型对公交驾驶员危险知觉的影响

结合反应时方法和多维度驾驶风格量表,以140名公交驾驶员为研究对象,采用2（危险类型：隐藏危险、明显危险）×2（驾驶员分组：有无交通违规/事故记录）的混合实验设计考察危险类型对危险知觉的影响。结果发现：驾驶员对明显危险的反应时比隐藏危险短,无交通违规/事故记录驾驶员对明显和隐藏危险的反应时均比有交通违规/事故记录驾驶员短。控制驾驶风格后,危险类型主效应不再显著。结果表明,公交驾驶员危险知觉的特点随着危险类型不同而变化。     

The contribution of memory to differences in situation awareness in expert and non-expert drivers

Situation awareness (SA) is knowing what is going on in the environment: identifying objects, understanding how they interact and predicting future events. It is important in the context of driving as it is related to hazard perception. Driving-related SA may help explain expert drivers’ superior driving skill, but it is important to understand whether this is because expert drivers have better memory for driving-related tasks, whether superior memory performance is task specific, and the degree to which any effect is attributable to experience vs. expertise. On-road paramedics were compared with non-expert drivers. The participants engaged in an SA driving task where they were required to describe a vide taped driving situation after the screen cut to black. We measured their SA, memory and demographic driving variables. The starting SA of World, Action and Schema was re-developed to better reflect driving SA, into World, Action, Other-Agent Action, Projection, and Rationale. Driving expertise predicted each category of SA, except the Action category, independently of other experience variables. Similarly, expertise also predicted SA categories independently of any of the memory tasks. We concluded that expert drivers have better driving-SA than non-expert drivers and this is not due to better memory for driving tasks, or ‘time-on-road’. This finding is important in driver training because if we can harness the SA skills that expert drivers demonstrate, we could potentially implement them in better driver training programs.     

驾驶经验和危险类型对驾驶员危险检测的影响

结合反应时和信号检测方法,考察不同危险类型下驾驶员危险检测的特点。35名新手和35名有经验驾驶员依次完成一个反应时测试和一个信号检测任务。结果发现：新手对明显和隐藏危险的反应时间比有经验驾驶员长。与隐藏危险相比,驾驶员对明显危险的敏感性高、判断标准低。驾驶员对两类危险的反应时间长是因为他们的判断标准严格。研究结果表明,驾驶员危险检测的特点随着危险类型不同而变化。     

驾驶经验和危险类型对驾驶员危险检测的影响

结合反应时和信号检测方法,考察不同危险类型下驾驶员危险检测的特点。35名新手和35名有经验驾驶员依次完成一个反应时测试和一个信号检测任务。结果发现：新手对明显和隐藏危险的反应时间比有经验驾驶员长。与隐藏危险相比,驾驶员对明显危险的敏感性高、判断标准低。驾驶员对两类危险的反应时间长是因为他们的判断标准严格。研究结果表明,驾驶员危险检测的特点随着危险类型不同而变化。     

The relationship between cognitive function and hazard perception in younger drivers

Driving is a complex task; with research suggesting cognitive function plays a significant role in driver behaviour. Recent studies have investigated the role of cognitive function in younger drivers who are experiencing brain maturation and are over-represented in crash statistics. Emerging evidence suggests poor cognitive functioning is one explanation for this high crash risk. For younger drivers, the relationship between cognitive function and driving ability has been consistently shown for speeding and lane deviations. However, the driving skill most consistently linked to crash involvement is hazard perception, which is the ability to anticipate and respond to potentially dangerous traffic situations. The aim of this study was to investigate the cognitive correlates of hazard perception in younger drivers. Seventy-nine undergraduate students completed a hazard perception test and a battery of cognitive tests that have previously demonstrated a relationship with safe driving. The newly created hazard perception test measured accuracy of hazard identification, response times when anticipating the hazard, and response times when taking action to avoid the hazard. Hazard perception accuracy was significantly related to visuo-spatial skills, executive functioning and global cognitive status. Anticipation response times were significantly related to inhibitory control, with no significant relationship found between cognitive function and action response times. These findings are discussed in line with limitations in the study. Future research into the role of specific cognitive domains could lead to the enhancement of hazard perception testing for licensing with cognitive training and assessment, with the potential to reduce the crash risk of vulnerable younger drivers.     

自我评估的能力与驾驶经验对危险知觉的影响

结合反应时和眼动研究方法,采用驾驶经验2（新手,有经验）×自我评估的能力2（高,低）×危险类型2（明显,隐藏）的混合实验设计,探索驾驶员驾驶能力的自我评估和驾驶经验对危险知觉及视觉注意的影响。采用驾驶能力量表和基于动态交通视频的危险知觉任务对86名驾驶员测试,并使用Tobbi T120记录眼动数据。结果发现,新手和有经验驾驶员自我评估的能力与危险知觉反应时间之间相关不显著,这说明两组驾驶员对自己驾驶能力的认识和评估不准确。有经验驾驶员对两类危险的反应比新手快。新手自我评估的能力过高,他们对两类危险的反应比同龄驾驶员和有经验驾驶员慢。然而,有经验驾驶员自我评估的能力与危险知觉反应时间之间不存在显著差异。此外,与新手相比,有经验驾驶员对两类危险的首次注视较快,总注视时间更长。与同龄驾驶员相比,新手自我评估的能力过高,他们对危险的首次注视较慢,对危险的总注视时间更少。这些研究结果表明,新手自我评估的能力过高,可能会提高他们的风险接受阈限,由此降低了他们对危险的反应速度。未来驾驶训练应当采取措施减少新手对驾驶能力的自我评估偏见,改善他们的视觉搜索模式以降低事故风险。     

Effects of hazard exposure and roadway complexity on young and older driver situation awareness and performance

Few previous studies of driver situation awareness (SA) have focused on behavior in hazard negotiation. The objective of this research was to assess the effect of hazard exposure on driver SA and interactions with age and roadway complexity. Ten young (18–25 yrs) and ten older (65–81 yrs) participants drove in a simulator under two levels of environment complexity (simple – rural vs. complex – city) with two types of hazard exposure (static vs. dynamic). Situation awareness was measured using real-time probes posed by a confederate passenger. Driving performance was assessed in terms of lane maintenance and speed control. Results revealed hazards to cause degradations in high level of driver SA and speed control or to trigger adaptation, and vulnerability to hazard type was dependent on driver age. Older drivers exhibited greater speed reduction in response to dynamic hazards; whereas, young driver maintained higher speed, as compared to normal driving, when confronted with static hazards. In addition, increased roadway environment complexity compounded decrements in performance caused by hazard exposure. These findings are applicable to modeling driver behavior and SA under hazardous conditions and may support the design of new in-vehicle assistive technologies for hazard avoidance.     

A method to improve the hazard perception of young novice drivers based on Bandura’s observational learning theory: Supplement to expert commentary training

Compared with experienced drivers, young novice drivers are more likely to have traffic accidents. The main reasons are that they lack experience, their hazard perception is weak, and their visual search strategy is underdeveloped. Research shows that hazard perception training can improve the visual search strategy of young novice drivers and enhance their hazard perception ability. We propose that a driver's visual search behaviour, like any other action, can be developed by observing the behaviour of a role model. In an experiment based on a driving simulator, we clustered the visual search paths of 20 experienced drivers, selected the drivers with the best visual search behaviour, and obtained visual search path video footage to produce hazard perception training videos. Using these videos, we applied Bandura’s observation learning theory to train 20 young novice drivers. We call this approach “training based on experienced drivers' performance”. To determine the effects of training based on experienced drivers' performance, 20 young novice drivers were given the usual expert commentary training, and 20 young drivers were given no training. The results showed that training based on experienced drivers' performance and expert commentary training had positive effects on the average speed of young novice drivers through hazard sections. Compared with untrained young novice drivers, trained young novice drivers decreased their speed in response to dangerous road sections. Compared with young novice drivers who received expert commentary training and those who did not receive training, young novice drivers who received training based on experienced drivers' performance showed significant improvements in visual search. These results suggest that training based on experienced drivers' performance can help young novice drivers improve their hazard perception, especially in visual aspects. This training method can complement existing training methods for young novice drivers.     

Take over! A video-clip study measuring attention,situation awareness,and decision-making in the face of an impending hazard

In highly automated driving, drivers occasionally need to take over control of the car due to limitations of the automated driving system. Research has shown that visually distracted drivers need about 7 s to regain situation awareness (SA). However, it is unknown whether the presence of a hazard affects SA. In the present experiment, 32 participants watched animated video clips from a driver’s perspective while their eyes were recorded using eye-tracking equipment. The videos had lengths between 1 and 20 s and contained either no hazard or an impending crash in the form of a stationary car in the ego lane. After each video, participants had to (1) decide (no need to take over, evade left, evade right, brake only), (2) rate the danger of the situation, (3) rebuild the situation from a top-down perspective, and (4) rate the difficulty of the rebuilding task. The results showed that the hazard situations were experienced as more dangerous than the non-hazard situations, as inferred from self-reported danger and pupil diameter. However, there were no major differences in SA: hazard and non-hazard situations yielded equivalent speed and distance errors in the rebuilding task and equivalent self-reported difficulty scores. An exception occurred for the shortest time budget (1 s) videos, where participants showed impaired SA in the hazard condition, presumably because the threat inhibited participants from looking into the rear-view mirror. Correlations between measures of SA and decision-making accuracy were low to moderate. It is concluded that hazards do not substantially affect the global awareness of the traffic situation, except for short time budgets.     

Training interventions are only effective on careful drivers,not careless drivers

Drivers aged 16–24 are overrepresented in fatal crashes compared to middle-aged, more experienced drivers. This age-related difference in crash rates partly arises from younger drivers’ poorer performance on three cognitive skills known to be related to crash involvement: hazard anticipation, hazard mitigation and attention maintenance. Training programs have been shown effective at improving these skills within a short period of time. However, young drivers are not homogenous and they have different driving styles. The driving styles can interact with driving skills by influencing both their acquisition and, once acquired, their execution. A study was undertaken on a driving simulator to determine whether the effectiveness of an already existing training program aimed at improving the three above mentioned skills is moderated by driving style. In particular, drivers were classified as either careful or careless drivers based both on their scores on measures designed to evaluate two general traits relevant to discriminating between careful and careless drivers (sensation seeking and aggressiveness) as well as on their scores designed to evaluate driving specific behaviors that discriminate between careful and careless drivers (aggressive driving behaviors and driving violations and errors). It was found that training improved the hazard anticipation and attention maintenance performance of only the careful drivers, not the careless drivers.     

An online hazard perception training course reduces heavy braking,speeding, and over-revving rates during everyday driving

In essence, driver training involves learning the skills required to drive safely and avoid dangerous events. However, in traditional on-road driver instruction, drivers virtually never accrue experience of the most significant types of events that they are learning to avoid: crashes. One means of providing this experience safely is to present novice drivers with video clips of real crashes, as part of structured learning exercises. A six-week automated online hazard perception training course for drivers, incorporating evidence-based training methods and over a hundred crash clips, was previously found to improve novice drivers’ hazard perception skill, which is known to be an important attribute for avoiding crashes. However, since hazard perception was measured using computer-based methods, the possibility remained that the training effect might not transfer to actual driving. We report a randomized control trial in which novice drivers were recruited to assess everyday driving behaviour objectively, using g-force triggered dashcams and GPS trackers installed in their vehicles. On-road data were collected for a one-month baseline period, and for a further two months after half of the sample completed the hazard perception training course. Drivers who completed the course significantly reduced their rate of heavy-braking events, their speeding behaviour, and their rate of over-revving events. These findings support the proposal that a relatively inexpensive and highly scalable hazard perception training intervention can improve on-road driving behaviour, with the clear potential to impact real-world driver safety.     

Scores on a new hazard prediction test are associated with both driver experience and crash involvement

Hazard perception skill has been found to be associated with drivers’ crash risk. This skill has typically been measured using computer-based response-time hazard perception tests, in which drivers indicate the earliest point that they detect a potential hazard in video clips of traffic filmed from a driver’s perspective. In recent years, researchers have suggested an alternative type of measure, known as a “hazard prediction test”, in which each test item is a traffic clip that stops (typically cutting to black) just before a hazardous incident unfolds. Drivers taking the test have to predict what happens next in the clip. Measures of this kind have been found to distinguish between high risk (novice) and lower risk (experienced) driver groups, and have been argued to offer several advantages over traditional response-time hazard perception tests. However, a key strength of the response-time hazard perception test is that assessments using this format have been found to predict crash involvement. The same has not yet been demonstrated for hazard prediction tests, raising questions about their validity. In the present research, we created a new hazard prediction test using Australian traffic scenes. In our version of the test, drivers’ scores were based on how many plausible predictions they were able to generate for each traffic clip. We established validity evidence for the test scores in two studies with separate samples, using two different versions of the test (long vs. short) with different response modes (verbal vs. written). As well as distinguishing between novice and experienced driver groups, test scores were also associated with self-reported crash involvement in both studies. We also found a significant correlation between hazard prediction test scores and scores in an established response-time hazard perception test. These findings support the proposal that scores on the hazard prediction test are a valid measure of hazard perception skill.     

The differences in hazard response time and driving styles of violation-involved and violation-free taxi drivers

The present study aimed to investigate the relationships between taxi drivers’ traffic violations in past driving and two domains: driving skill (hazard perception skill) and driving style. Five hundred and fifty taxi drivers aged 25 – 59 were recruited to finish a video-based hazard perception test and the Chinese version of the Multidimensional Driving Style Inventory (MDSI). The relationships between hazard response time, driving style and traffic violations were examined, and the differences in hazard response times and driving styles of violation-involved drivers (n = 220) and violation-free drivers (n = 330) were compared. The results showed that taxi drivers’ traffic violations are closely related to their driving styles and hazard response time. Violation-involved drivers scored significantly higher in hazard response time and maladaptive driving styles (i.e., anxious, risky and angry styles) and lower in careful driving style than violation-free drivers. More importantly, drivers’ hazard response time and driving styles can effectively predict their violation involvement in the last 12 months with an overall classification accuracy of 66.4%. The findings provide evidence for the usefulness of video-based hazard perception tests and the MDSI in taxi driver testing and training.     

Distraction while driving: The case of older drivers

As the impairment of older drivers is especially found in perception and attention, one could assume that they are especially prone to distraction effects of secondary tasks performed while driving. The aim of the study was to examine the effect of age on driving performance as well as the compensation strategies of older drivers under distraction. 10 middle-aged and 10 older drivers drove in a simulator with and without a secondary task. To assess driving performance the Lane Change Task (Mattes, 2003) was used. This method aims at estimating driver demand while a secondary task is being performed, by measuring performance degradation on a primary driving-like task in a standardized manner. The secondary task – a self-developed computer-based version of “d2 Test of Attention” was presented both with and without time pressure. The results show that older participants’ overall driving performance (mean deviation from an ideal path) was worse in all conditions as compared to the younger ones. With regard to lane change reaction time both age groups were influenced by distraction in a comparable manner. However, when the lane keeping performance (standard deviation of the lateral position) was examined, the older participants were more affected than the younger ones. This pattern could be explained by compensation strategies of the older drivers. They focused on the most relevant part of the driving task, the lane change manoeuvres and were able to maintain their performance level in a similar way as did younger drivers. The driving performance of the older participants was not additionally impaired when the secondary task imposed time pressure. Overall, subjective rating of driving performance, perceived workload and perceived distraction was found to be similar for both age groups. The observed trends and patterns associated with distraction while driving should contribute to the further research or practical work regarding in-vehicle technologies and older drivers.     

Self-perception of driving abilities in older age: A systematic review

Older adults have become the fastest growing age group worldwide and will continue to make up a more significant portion of the driving population. Given the increased potential for age-related perceptual, cognitive, and physical declines, it is important to understand the perception that older drivers have regarding their own driving abilities. This awareness often motivates their driving behavior and patterns.A systematic review was conducted to synthesize the literature regarding the self-perception of driving abilities in older age. The PRISMA method was used and 10 databases (SCOPUS, TRID, PsycINFO, AgeLine, Web of Science, Abstracts in Social Gerontology, Inspec, Compendex, PubMed, and Medline) were searched to identify relevant articles. A total of 25 articles met the search criteria and were included in the qualitative synthesis.Overall, methods used to assess self-perception of driving abilities in older adults vary considerably. Some studies employ only subjective questionnaires, while others administer questionnaires in addition to on-road driving or simulated evaluations. Nonetheless, the studies overwhelmingly report that older drivers tend to rate highly, and often overestimate, their driving abilities. They perceive their driving abilities to be better than themselves at a younger age, their cohorts, and all other drivers. However, more work is needed to develop improved subjective assessments that guide drivers in more accurately estimating their true driving abilities, as well as to compare subjective ratings to objective performance-based measures of driving abilities.This review may assist researchers in better understanding the characteristics that influence driving self-perception and may inform the development of interventional strategies that help older drivers to better calibrate how they perceive their driving.     

Young drivers’ perception of hazards: Variation with experience and day versus night

Young novice drivers have a relatively high crash risk for several years following initial licensing, and while all drivers are at greater risk at night, the night-time increase is greater for inexperienced drivers. Poor hazard perception has been identified as an important contributor to inexperienced drivers’ risk, but research on day-night differences in hazard perception for drivers varying in experience is lacking. This exploratory study investigated the nature of hazards reported by young inexperienced drivers versus more experienced and slightly older drivers. Hazards were not pre-identified by researchers; participants were simply provided with a general definition of ‘hazard’. Analysis focused on how experience level affected qualitative differences in the kinds of hazards reported, with particular focus on day-night differences.The 53 participants ranged in driving experience from learners through to 5+years post licensing, and in age from 16 to 30 years. They viewed 14 day- and night-time video clips of a diverse range of driving situations, pausing the video whenever they identified a hazard and then explaining why they had paused it at that point. Their responses were recorded. Content analysis of responses showed that more experienced drivers reported visibility-related hazards significantly more often than inexperienced ones, and significantly more so at night. They also commented significantly more on hazards related to tight bends in the road and significantly less on hazards concerning compliance with rules. Comments tended to be fewer with higher vehicle speeds, particularly for the least experienced drivers.Results are discussed in terms of how experience-related differences in drivers’ cognitive schemata and mental models are likely to affect hazard perception and crash risk, particularly at night. Some implications for driver training and license testing are suggested.     

影响驾驶安全的驾驶员危险知觉研究述评

危险知觉是指驾驶员对交通情境中的潜在危险进行识别并做出反应的一种能力。目前,驾驶员危险知觉测量主要使用反应时、眼动或主观评定三种测量方法。在测量中,这三种方法各有优缺点,并出现相互结合的研究趋势。为了提高我国交通安全性,结合国外在提高驾驶员危险预期能力和改善视觉搜索模式两个方面的应用研究,未来国内研究可以在探索危险知觉的认知加工特点、影响因素及加快测量技术的商品化应用等方面加以深入。     

Risk perception in novice drivers: the relationship between questionnaire measures and response latency

The extent to which questionnaire based measures of driving risk, driving ability and accident likelihood are associated with response latency based measures obtained on a hazard perception test was examined. In Experiment 1 questionnaire evaluations of driving in general were obtained and correlated with hazard perception performance. In Experiment 2 questionnaire evaluations and hazard perception performance were obtained when drivers viewed the same driving scenes. In neither experiment did questionnaire responses correlate significantly with hazard perception performance. Additionally while in both experiments no difference in hazard perception performance arose between males and females, females rated driving as more risky and their ability to be lower than males. The results indicate independence between questionnaire and response latency measures of hazard perception. However the possibility that both approaches should be adopted within a single framework is raised.     

The perception of team engagement reduces stress induced situation awareness overconfidence and risk-taking

Much research has examined how stress restricts objective Situation Awareness (SA). Little research, however, has focused on SA overconfidence, the notion that an individual may grasp a situation when in fact they do not. Even less SA research has examined the motivational and emotional states of individuals operating in teams in stressful environments. Expanding on recent data suggesting that stress creates SA overconfidence, not simply SA loss, the present experiment manipulated stress levels and the perception of team engagement, which is thought to be a positive motivational state of task-related well-being. Teams of Soldiers were tested in a virtual combat scenario testing shared risk-taking, objective (i.e., collaborative ability to answer SA probes), and subjective SA. Results indicated that the mere perception of above average team engagement reduced stress induced SA overconfidence and risk-taking of teams. These results suggest simple, virtually costless strategies for improving elements of SA that may impact the behavior of teams and potentially improve their decision-making.