Validation of an Eye-Tracking System for Use in Driving Simulator Research

Eye-tracking has been widely used for decades in vision research, language, and usability. In the area of road engineering, the eye-tracking system has been used both for on-field and in driving simulation studies. The overall advantage of using an eye-tracker is that different parameters regarding eye-movement towards visible stimuli in the environment can be measured, such as eye-fixations and saccades. Several studies have been developed by combining the benefits of the eye-tracking system with driving simulators to simultaneously investigate driving behaviour and the potential source of distraction. However, little effort has been spent in terms of eye-tracking validation in the driving simulator environment. To fill this gap, both a field survey and a driving simulation experiment have been developed for a case study located in Rome, Italy. The selected road sections and events have been reproduced on the fixed-based driving simulator system at the Department of Engineering of Roma Tre University. A Tobii glasses eye-tracking system has been used to record the eye movements both on board of a real vehicle and on the simulator. The eye movements of 14 participants in the field survey and 18 participants in the driving simulation tests, as well as their driving performances (speeds, accelerations, trajectories), have been investigated while approaching an urban intersection and in relation to two specific road events, both static and dynamic: i) the presence of a speed limit sign and ii) the presence of a crossing pedestrian. Eye tracker parameters and driving performances were compared between the real driving tests and driving simulator experiments in order to validate the eye-tracking system. Specifically, the eye-tracking system has been validated for both the events in terms of duration and distance of the eye fixation. Therefore, the results demonstrate that the eye-tracking system stands as an effective tool for studies and applications in a virtual reality environment.