Driver gaze monitoring for combatting distracted driving: A comparison of duration thresholds of eyes-off-road warnings and their effects on hazard detection

Ginnie Wee¹, Jiali Song¹, Benjamin Wolfe¹; ¹University of Toronto Mississauga

Safe driving requires timely responses to hazards. Visual distraction, such as texting, slows response time and increases the incidence of errors. These include looked-but-failed-to-see (LBFTS) errors, where drivers miss hazards despite having looked at them, and didn’t-look-and-didn’t-see (DLDS) errors, where gaze is not proximate to the hazard and it is missed. Distracted drivers tend to have longer eyes-off-road (EOR) durations, and some vehicles provide warnings when EOR durations exceed a threshold (which varies by jurisdiction; 2s in North America, 3s in the EU). However, even under distraction, EOR glances are typically below these thresholds. Consequently, warnings may not be provided to drivers, limiting their utility. We investigated if shorter EOR warning thresholds of 1s and 1.5s reduced LBFTS and DLDS errors. Twenty licensed drivers (mean age = 19.4, SD = 2.5) located hazards in 320 dashcam videos while simultaneously performing a secondary visual task. Eye movements were monitored and visual warnings were deployed whenever gaze lingered outside of the video boundaries for longer than the threshold duration. All drivers completed warning absent and present blocks, with block order counterbalanced. EOR warnings decreased the incidence of missed hazards but did not increase the frequency of looking at hazards, indicating that EOR-based visual warnings facilitate awareness even if they do not guide gaze to hazards. EOR warnings also decreased the incidence of DLDS errors, indicating that warnings help drivers return their attention to the road. However, they failed to decrease the incidence of LBFTS errors, suggesting that they did not improve hazard recognition when attention is already on the road but is impaired by distraction. These results suggest that while lowering EOR thresholds may help reduce the impact of distraction, it cannot solve the problem of visual distraction behind the wheel.

Acknowledgements: This work was funded by Transport Canada Enhanced Road Safety Transfer Payment Program.