Effects of Automation Reliability on Driver Vigilance

Partially automated vehicles rely on drivers to monitor for automation errors and environmental hazards to which the automation may not respond. However, driver vigilance declines over time, leading to potential safety risks associated with detection failure. This study measured driver trust, workload, stress, and ability to detect automation errors. Automation reliability was manipulated (high vs. low). Findings revealed no significant differences in performance, workload, or trust between high and low reliability conditions. The lack of reliability differences for performance, workload, and trust suggests more severe reliability variations may be needed to produce observable effects. However, the low reliability condition experienced heightened distress and worry emphasizing the effect of reliability on emotional state. All drivers became less responsive as a function of time (i.e., conservative bias shift). Drivers also reported decreased engagement and increased distress. This underscores the need for automation improvements that enhance engagement without increasing negative emotion states.