Empirical studiesBy Noé Monsaingeon, Loïc Caroux, Sabine Langlois, Yovan Hurgobin, Céline Lemercier
The automated systems of partially automated vehicles can suddenly and frequently deactivate depending on the characteristics of the environment. Manufacturers are considering the possibility of mounting a visual indicator inside the vehicle to inform drivers about the reliability of automated systems. The present study was designed to evaluate the influence of reliability information and environmental conditions on drivers’ judgment to the decision to deactivate the automated systems and take back control of the vehicle in partially automated cars. A total of 199 participants aged 19-67 years were exposed to 16 realistic scenarios describing situations in which a character is driving a partially automated vehicle. They had to rate their judgment of agreement with the character’s decision to deactivate the automation, depending on the color of an indicator of proximity to the limit of automation (green: reliable vs. orange: close to the limit), the weather (very sunny vs. raining heavily), the quality of the road markings (clear vs. blurred), and the curvature of the road (straight vs. bends). The results revealed that all four factors influenced the decision to deactivate the automation. A complementary cluster analysis revealed that the results also needed to be interpreted in relation to the driver’s profile (i.e., gender, trust in automated vehicles, and experience with automated vehicles). These findings suggest that user profiles should be considered when deciding whether to include an indicator of reliability in partially-automated vehicles.