Investigation of Habituation Effects of Visual Variations of Cues to the Fallback-Driver for Automated Level 3 Vehicles

In L3 conditional automated driving, the fallback driver may disengage from the driving task but must remain ready to resume control when requested.A major challenge is maintaining this readiness without compromising user experience.Most systems lack ongoing proactive cues to sustain engagement, and existing ones are often so monotonous they quickly become habituating.This video paper examines whether varying the visual design of periodic engagement cues can reduce habituation and sustain driver readiness.In a within-subjects experiment (N=5), participants experienced a Wizard-of-Oz video driving simulation with head-up display messages presented every three minutes, using either (a) a fixed or (b) a variable alert design.Results from a 3-point Likert scale and post-test semi-structured interviews suggest that variation reduces perceived repetition, supports engagement, and is not perceived as annoying.Our findings indicate that subtle, varied visual cues may be a promising approach to maintain fallback readiness.