The effect of inconsistent steering guidance during transitions from Highly Automated Driving

Area of Science:

• Human-Computer Interaction
• Automotive Engineering
• Cognitive Psychology

Background:

• Highly Automated Driving (HAD) systems require seamless transitions between automation and human control.
• Understanding driver engagement during these transitions is crucial for safety and system acceptance.
• Inconsistent steering guidance may pose challenges for drivers regaining control.

Purpose of the Study:

• To investigate the impact of inconsistent steering guidance on driver engagement during system and user-initiated transitions from HAD.
• To determine if steering conflicts accelerate driver steering engagement.
• To analyze the influence of transition initiation on steering behavior and control.

Main Methods:

• A driving simulator study was conducted to assess driver responses.
• Inconsistent steering guidance was implemented by toggling guidance on/off at frequencies of 0.1, 0.2, and 0.3 Hz.
• Driver steering inputs, Time To Lane Crossing (TTLC), and engagement timing were measured during system- and user-initiated transitions.

Main Results:

• Driver engagement was primarily influenced by the initiation of the transition, not the quality of guidance.
• Drivers showed stronger steering inputs and maintained higher TTLC values in user-initiated transitions.
• In system-initiated transitions, drivers began actively steering after 5 seconds, achieving user-initiated transition behavior by 10 seconds.

Conclusions:

• The initiation of a transition (user vs. system) is a key factor in driver steering engagement.
• User-initiated transitions result in more immediate and effective driver control compared to system-initiated ones.
• System design should consider the timing and nature of transition initiation to optimize driver engagement and safety.