Speed behaviour and mental workload of small-spacing expressway interchanges based on field driving test

Area of Science:

• Traffic Engineering
• Human Factors Psychology
• Transportation Safety

Background:

• Small-spacing interchanges (SSI) are increasingly common on expressways.
• Understanding driver behavior and workload in SSIs is crucial for safety.

Purpose of the Study:

• To investigate speed and mental workload characteristics in SSIs.
• To determine the influence of speed on driver workload.

Main Methods:

• 37 participants completed field driving tests under four conditions.
• Collected speed data and driver electrocardiogram (ECG) for heart rate increase (HRI) analysis.
• Developed a speed-HRI relationship model.

Main Results:

• Speed variations showed 'decrease-increase' and 'continuous decrease' patterns.
• Driver HRI exhibited 'convex', 'increasing', 'decreasing', and 'concave' patterns.
• Higher HRI observed during ramp-mainline merging, indicating increased driver nervousness.

Conclusions:

• Vehicle weaving significantly impacts driver mental workload within SSIs.
• A positive correlation exists between vehicle speed and driver HRI.
• SSI influenced area length can be determined by speed and HRI patterns.