How does drivers' attention change when using a two-stage warning system? Effects of expectation and cognitive load

Area of Science:

• Human-Computer Interaction
• Automotive Engineering
• Cognitive Psychology

Background:

• Two-stage warning systems are crucial for safe transitions in Level 3 automated driving systems.
• Driver expectations and cognitive load significantly influence performance during automated driving.
• Understanding attention allocation is key to optimizing driver interaction with automated systems.

Purpose of the Study:

• To investigate the impact of driver expectations and cognitive load on attention and takeover performance with two-stage warnings.
• To analyze how drivers' perceptions of automated driving capabilities affect their response to warnings.
• To determine the relationship between cognitive load and attention strategies during automated driving transitions.

Main Methods:

• A driving simulation study involving 32 participants using a Level 3 automated driving system.
• Manipulation of driver expectations (high vs. low) regarding system capabilities.
• Assessment of cognitive load and its effect on drivers' visual attention and takeover performance.

Main Results:

• High cognitive load led to increased road fixation, indicating a cautious attention strategy.
• Drivers with high expectations of automated systems exhibited less road gazing and poorer takeover performance (increased lateral deviation, acceleration).
• Attention allocation in high-expectation drivers was less sensitive to warning stages but more affected by cognitive load.

Conclusions:

• Two-stage warning systems require careful design to effectively guide driver attention, especially under varying cognitive loads and expectations.
• Driver expectations play a critical role in attention allocation and takeover performance, necessitating calibration of these expectations.
• Future designs should consider individual differences in cognitive load and system expectation to enhance safety in automated driving.