# Situational Awareness Assessment of Drivers Boosted by Eye-Tracking Metrics: A Literature Review
###### Abstract  
The conceptual framework for assessing the situational awareness (SA) of drivers consists of three hierarchical levels: perception of the elements of the environment, comprehension of the elements, and decision-making in the near future. A common challenge in evaluating SA is the determination of the available subjective and objective techniques and their selection and integration into methodologies. Among the objective techniques, eye tracking is commonly used, considering the influence of gaze behavior on driving. This review is presented as an innovative approach to the subject matter, introducing physiological metrics based on eye tracking and investigating their application in assessing the SA of drivers. In addition, experiments and methodologies that revealed patterns at the three levels of SA were identified. For this purpose, databases were searched, and 38 papers were considered. Articles were clustered according to prevalent themes such as eye-tracking metrics, eye-tracking devices, experiment design, and the relationship between SA and eye-tracking. This review summarizes the main metrics and key findings for each article and reveals a wide relationship between the eye-tracking metrics and SA. The influence of appropriately calibrated equipment, refined data collection protocols, and adequate selection of the eye-tracking metrics was examined. Further reviews are needed to systematically collect more evidence. situational awareness; eye tracking; driving; gaze behavior; naturalistic driving; simulation-based experiments +
Footnote †: journal: _Sci. In the latter type, freeze-probe methods are commonly used. In this latter approach, participants are prompted to respond to a series of queries at a specific juncture during task execution; the task is then momentarily suspended, with or without prior notification, and the provided responses are juxtaposed with the prevailing circumstances; an example of a freeze-probe method is the situational awareness global assessment technique. Eye tracking is another objective technique that is conducive to real-time participant analysis and involves physiological measurements. Eye tracking has been extensively employed for quantifying human performance and behavior. It presents a promising and viable alternative for appraising SA, and it can overcome the constraints associated with alternate approaches. This technique offers the distinct advantage of facilitating real-time measurements or assessments within simulated contexts while minimizing disruptions [7]. It mitigates problems such as participants resorting to long-term memory utilization, which is encountered in freeze-probe methods, to elucidate subtasks or elaborate on task-specific details [8]. Eye tracking is one of the most commonly used techniques in SA research [9]. In HFE, operational difficulties can occur during an activity when SA is lost or when mental breakdowns occur during complex tasks [3]. SA assumes a pivotal role in the examination of performance in intricate tasks. It is characterized by the swift assimilation of stimuli and environmental information, coupled with the demand for long-term memory utilization. Thus, SA plays a particularly salient role in scenarios marked by persistent disruptions that originate from shifting surroundings and necessitate a discerning decision-making process about impending events. An important example of such multifaceted tasks is the act of driving [5; 10; 11; 12]. SA has received immense attention over the past years in different fields of study, particularly in the field of driving [5; 13]. The cognitive functioning and measurement of the SA is a key field of study of the performance and behavior of drivers. For instance, a previous study reported that 87.5% of drivers identified distracted driving as a greater concern compared to the past, while 87.9% perceived drowsiness as a safety threat [14]. The utilization of an eye-tracking device is a prevalent and extensively employed methodology for quantifying user performance and behavior.