Beyond distraction: unraveling touchscreen effects on driver takeover performance and visual attention dynamics in Level 3 automated driving

Rapid advances in automated driving technology and the widespread adoption of in-vehicle information systems (IVIS) have led to an increasing prevalence of drivers engaging in non-driving-related tasks (NDRTs) during autonomous operation, thereby introducing potential safety hazards. In this study, we conducted a driving simulator experiment with 30 participants to examine the effects of IVIS NDRTs (i.e., navigation, video, audio, and reading tasks) and takeover time budgets on takeover timing, takeover quality, and visual behavior. Results from linear mixed-effects models indicate that IVIS touchscreen interactions significantly prolonged takeover time and lane change time, increased maximum lateral acceleration, and reduced minimum time-to-collision (TTC), suggesting that drivers adopted aggressive control behaviors during takeovers, which in turn elevated collision risk. Moreover, visual behavior analysis revealed an increased proportion of long glances directed away from the forward roadway and a delayed reallocation of visual attention to key regions (such as mirrors, the road, and the malfunctioning vehicle) following the takeover request. These findings enhance our understanding of human factors in automated driving and provide empirical evidence for optimizing driver-vehicle interaction protocols and improving the safety of riding in conditionally automated driving systems.