Evaluating the Effects of Secondary Tasks on Driver Gaze Duration: A Duration Modeling Approach

In simulating drivers’ engagement in secondary tasks in a driving simulator, the objective of this study was to investigate drivers’ gaze duration when performing the tasks, reflecting the time away from the driving scene (commonly referred to as total eyes off road time [TEORT]). Eighty-five participants engaged in the secondary tasks on a driving simulator at University of Kansas, KS. TEORT values were extracted using an eye-tracker for secondary tasks, which were then modeled using a duration modeling approach. Specifically, a correlated grouped random parameters accelerated failure time Weibull duration model with heterogeneity in the mean was developed, capturing the repeated nature of observations and allowing drivers’ gaze durations to be heterogeneous. The random parameter for Age Group 1 suggested that most young drivers (54%) took a shorter time to complete the secondary task, whereas the random parameter for Age Group 3 indicated that about 58% of older drivers took a shorter time to complete the secondary task. These results showed significant heterogeneity in TEORT and mixed effects on safety, whereby drivers’ longer gaze duration indicated risky behavior. The findings of this study confirmed that not only was the driving behavior of one specific age group (Age Group 1) riskier than the others but that the risk within each group was not uniform—individual drivers within an age group exhibited significantly different TEORT, suggesting the need for more nuanced, intragroup analysis. The study highlights how analyzing gaze behavior can aid in designing advanced driving assistance systems to minimize distraction.