Hazard perception performance and visual scanning behaviours: The effect of sleepiness

Driver sleepiness accounts for a substantial proportion of crashes in Australia and Worldwide. Young adults are overrepresented in sleep-related crashes and are more susceptible to sleepiness, resulting in impaired attention and driving performance. Visual scanning behaviour can affect the role between attention and information acquisition from the driver's environment. Thus, if attention is impaired, visual scanning behaviours are likely to show decrements as well. Overall, 32 young adults aged between 20 and 25 years completed a 60-minute hazard perception task to examine the effect of sleepiness and time-on-task on hazard perception performance, visual scanning behaviours, subjective sleepiness scores, and psychomotor vigilance test performance. The main outcomes include decrements in hazard perception performance and a restriction in horizontal and vertical eye scanning ranges across the 60-minute session, but with a more pronounced effect when sleep-restricted. These outcomes were consistent with increases in subjective sleepiness and behavioural metrics of sleepiness assessed via the PVT. Reductions in scanning range could limit opportunities to attend to hazards and other critical safety events. The current study outcomes provide an important contribution regarding the risks associated with sleepy driving performance.     

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.     

驾驶经验和危险类型对年轻驾驶员危险知觉的影响

结合反应时和眼动测量方法,采用驾驶经验分组2（年轻新手驾驶员,年轻有经验驾驶员）× 危险类型2（明显危险,隐藏危险）的混合实验设计,探索年轻驾驶员危险知觉的经验优势是否随着危险类型的不同而变化。使用一个基于真实交通情境视频的驾驶员危险知觉任务,对27名年轻新手驾驶员和22名年轻有经验驾驶员进行测试,并使用Tobbi T120记录眼动数据。结果发现,总体上,年轻新手驾驶员对潜在道路危险的反应次数比年轻有经验驾驶员更少,反应时间也更慢。两组驾驶员反应时间的差异,随着危险类型的不同而来源于不同的加工阶段。具体来说：一方面,年轻新手驾驶员对明显危险的反应时间慢,是因为他们对该类危险的评估时间长。另一方面,年轻新手驾驶员对隐藏危险的反应时间慢,是因为他们对该类危险的识别时间长。两组驾驶员对危险的平均注视时间受测试中危险类型的影响但不受驾驶经验的影响。这些研究结果表明,在对年轻新手驾驶员进行危险知觉训练或测试时,应重视危险类型对他们危险知觉的影响。     

The role of ecological validity in hazard perception assessment

Hazard perception is one of the few quantifiable components of driving competency that can explain the high crash risk of novice drivers (see Horswill & McKenna, 2004). Some studies focused on investigating the stimulus part of hazard perception items by comparing several design features of the displayed traffic scenarios (e.g. Malone et al., 2012; Scialfa et al., 2013). Other empirical studies have been conducted to address the reaction part of hazard perception items (e.g. Vlakveld, 2014). Among others, existing hazard perception tests differ with respect to the ecological validity – the similarity to real-world demands – of the task that has to be completed by the participants (simple reaction, hazard localization, simulated driving, etc.). Based on the findings of general expertise research (see Glaser & Chi, 1988), the hypothesis of the present experiment was that an increased ecological validity of a hazard perception task has a positive effect on the magnitude of performance differences between more and less experienced drivers. 104 learner drivers and 51 experienced drivers were randomly assigned either to a less ecological valid version (multiple choice task) or a higher ecological valid version (reaction task) of a hazard perception test. In both conditions, the same 20 animated hazardous or non-hazardous traffic scenarios were presented. Overall, the experienced drivers outperformed the learner drivers. Principally, both of the applied versions of the test provided a criterion valid measure of driving expertise. However, increasing the ecological validity of the test by using a reaction task was especially beneficial for certain types of scenarios, leading to higher expertise-related differences. In addition, the reaction task provides response time measure as a further valid performance indicator. This allows the identification of those participants who are indeed able to detect a hazard in a certain scenario, but still have deficits in response time, compared to more experienced drivers. According to the present study, it is recommended to choose the reaction task over the multiple choice task to test hazard perception. Whether a further increase in ecological validity of the task would be useful, should be tested empirically in future research.     

Situation Awareness: Its proficiency amongst older and younger drivers,and its usefulness for perceiving hazards

The two studies reported here sought to measure and compare the Situation Awareness (SA) of younger and older driver groups whilst driving (Study 1), and watching video footage of actual car journeys (Study 2). In both studies this was achieved by recording a participant’s commentary on what s/he felt was of relevance to the driving task. The narratives produced were analysed by computer software that could abstract main concepts and calculate scores indicative of Situation Awareness. In Study 2, these scores were related to others for hazard perception proficiency (also derived from participant commentaries). It was found that the older drivers matched and often exceeded the younger drivers when their SA scores were compared individually, but not when assessed as a group. However, the younger drivers out-performed their older counterparts in hazard perception ability, and this was shown to be related to their Situation Awareness score. When the results from participants who undertook both studies were compared, it was found that Situation Awareness performance was significantly higher when commenting on video footage (Study 2) than whilst actually driving (Study 1).     

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.     

The impact of Primacy/Recency Effects and Hazard Monitoring on attributions of other drivers

The present study examined the impact of Primacy/Recency Effects and Hazard Monitoring on driver attributions. Participants viewed a simulated near collision from the perspective of a trailing motorist. The amount of error free driving prior to the near collision varied between two groups, where the near incident occurred either early or later in their viewing experience. They were then given the opportunity to provide judgments of the offending driver based on how safe, dangerous, risky, and skilled the driver was in general, and to evaluate their overall performance. Results showed a Primacy Effect dominance in that judgments of the driver were most negative in the early group, but this was moderated by high Hazard Monitoring for ratings of “dangerous” and “safe”. This suggests that judgments of other drivers are likely to be quick and based on early information, but are impacted by personal factors such as a tendency to monitor for hazards.     

Driving simulator validation with hazard perception

How should we assess the comparability of driving on a road and “driving” in a simulator? If similar patterns of behaviour are observed, with similar differences between individuals, then we can conclude that driving in the simulator will deliver representative results and the advantages of simulators (controlled environments, hazardous situations) can be appreciated. To evaluate a driving simulator here we compare hazard detection while driving on roads, while watching short film clips recorded from a vehicle moving through traffic, and while driving through a simulated city in a fully instrumented fixed-base simulator with a 90 degree forward view (plus mirrors) that is under the speed/direction control of the driver. In all three situations we find increased scanning by more experienced and especially professional drivers, and earlier eye fixations on hazardous objects for experienced drivers. This comparability encourages the use of simulators in drivers training and testing.     

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.