Analysis of a driver's visual behaviour and its relationship with the smart road context

The authors, within the Samothrace project, proposed a complete characterization of the road driver through the knowledge of appropriate subjective, physiological and performance variables. In this paper, the role of the variation in pupil diameter and the blink rate, which belong to the class of physiological variables, will be further investigated, with the aim of recognising possible correlations between complex manoeuvres and an increased mental workload of the user. To this end, an experiment was carried out in a simulated environment where drivers wore an eye tracker capable of returning the diameter of the pupil in mm and the blink rate in the time domain. In the subsequent post processing phase these signals were related to the vehicle trajectory, steering angle, steering speed and speed. The results are quite promising, as both the blink rate and the variations in pupil size proved to be sensitive to two examined manoeuvres (a passing and a lane change due to a work zone), highlighting a good correlation with the trajectory of the vehicle. This information, if inserted within an overall architecture such as the one prepared by the authors as part of the Samothrace project, can profitably direct the design of appropriate driving assistant systems tools and improve road safety.