Comparing 2-level and 3-level graded collision warning systems under distracted driving conditions

Abstract

This study delves into a comprehensive exploration of driver performance by comparing the effects of a 3-level graded collision warning system with those of a 2-level graded system. Employing a within-between-subject design, the experiment seeks to unravel the impact of graded warning levels (2-stage and 3-stage) on driving performance in both normal and critical driving conditions. Forty participants were recruited to undergo precise testing within a controlled driving simulator environment. The experimental setup involves dividing participants into two groups, each exposed to distinct collision warning paradigms. The first group experiences a two-level graded warning system, while the second group encounters a three-level graded warning system, structured based on Time to Collision (TTC) metrics. Each participant drove eight scenarios, including four normal and four critical scenarios. This strategic design allows for a comprehensive evaluation of the influence of warning system intricacies on various facets of driving behavior. The study encompasses an array of dependent variables, including eye-tracking data, wristband-derived physiological metrics, driver response times, and the incidence of collisions. This multifaceted approach ensures a holistic understanding of the drivers’ reactions under different collision warning paradigms. Results indicated that the 3-level graded system significantly reduced response times and collision frequencies compared to the 2-level system across both normal and critical driving conditions. Additionally, the 3-level system demonstrated better mitigation of driver distraction. While driving conditions did not significantly affect eye-tracking data, the warning level had a significant impact, with the 3-level system showing superior results. However, neither warning level nor driving condition significantly affected physiological data, including Electrodermal Activity (EDA), Heart Rate (HR) and Heart Rate Variability (HRV). Subjective evaluations highlighted the impact of collision warnings on driver performance, particularly in high-speed scenarios. Moreover, auditory warning modalities were preferred by a majority of participants. These findings provide valuable insights for the development of advanced collision warning systems, emphasizing the importance of multi-level warnings and preferred warning modalities in enhancing driver safety and reducing collision risks in diverse driving environments.