Mode Errors and Intentional Violations in Visual Monitoring of Level 2 Driving Automation

Due to technical advancements, the driving task is changing from a manual task to system supervision. Research suggests that drivers do not always comply with safety requirements and neglect their monitoring task. On one hand, neglections in system monitoring could originate from mode confusion, with the driver assuming that the system is in a different mode than it actually is. In this case, insufficient system monitoring is the result of an unintentional mode error. On the other hand, drivers might deliberately omit system monitoring while knowing that the system is operating in a mode that requires constant surveillance. Such behaviour is considered an intentional violation. This study (30 participants) investigates the nature of neglections in visual system monitoring during a 60-minute simulator drive using eye-tracking data. The results reveal a substantial decline in system monitoring during Level 2, which further deteriorates with increasing time during which the system operates reliably. A systematic post-experiment interview reveals that more than half of the participants were aware of the system's mode (Level 2), and knew that the system actually required monitoring but still neglected their monitoring task.