Driver Situation Awareness and Cognitive Workload Effects of Novel Interchange Configurations and Associated Signage

Liu, Yunmei; Pyo, Kihyun; Cunningham, Christopher; Chase, Thomas; Kaber, David · 2022 · Crossref

DOI: 10.54941/ahfe1002459

archive: archived pipeline: cataloged verified

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Summary

This study addresses the lack of guidance on safely implementing signage for grade-separated interchanges (GSIs), which are designed to reduce congestion and conflict points but are susceptible to wrong-way driving. Specifically, the research investigates how novel GSI configurations (contraflow and quadrant) and associated signage (lane assignment and decision point signs) affect driver situation awareness (SA) and cognitive workload compared to standard intersections. The study also examines whether these effects vary by driver age or sign placement. The researchers conducted a driving simulation experiment using a high-fidelity, full-motion simulator with 48 licensed participants divided into young (18–24 years) and middle-aged (25–64 years) groups. The experimental design was a 2×2×3×2 mixed model, manipulating lane assignment sign presence (present/absent), decision point sign position (side/overhead), interchange type (standard, contraflow, quadrant), and age group. Participants navigated simulated urban environments, maintaining 45 mph and executing left turns. SA was measured using the Situation Awareness Global Assessment Technique (SAGAT), involving real-time queries paused during driving, while cognitive workload was assessed via the NASA-Task Load Index (NASA-TLX) completed after each trial. Results indicated that interchange configuration significantly impacted both SA and cognitive workload, but sign usage and placement did not. Driver SA was significantly lower in contraflow scenarios (mean 0.57) compared to standard (0.71) and quadrant (0.67) interchanges, with no significant difference between standard and quadrant designs. Similarly, cognitive workload was significantly higher in contraflow (38.86) and quadrant (36.19) configurations than in standard intersections (32.77). No significant differences were found between age groups or between the presence of lane assignment signs and the position of decision point signs. Correlation analysis revealed no significant relationship between SA scores and cognitive workload ratings, suggesting they are complementary, distinct measures of human performance. The findings imply that novel GSI designs, particularly contraflow configurations, degrade driver SA and increase cognitive workload, likely due to unfamiliarity and navigation complexity. While quadrant interchanges did not reduce SA compared to standard intersections, they did increase workload, indicating a need for improved signage to mitigate this load. The study concludes that current lane assignment and overhead decision point signs do not effectively enhance SA or reduce workload in these contexts. Engineers must develop novel signage strategies for contraflow interchanges to offset low SA and high workload, while quadrant designs may serve as feasible alternatives to standard intersections if signage is optimized to reduce cognitive demands.

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StageOutcomeToolModelPromptAttemptsCompleted
discover success Crossref 1 2026-06-07
archive success canonical_url 1 2026-06-09
extract success pdftotext 2 2026-06-09
clean success clean 1 2026-06-09
chunk success chunk 1 2026-06-09
embed success embed Qwen/Qwen3-Embedding-8B 1 2026-06-09
promote success 1 2026-06-07
summarize success llm qwen3.6-27b-prismaquant summ-v5 1 2026-06-09
tag success vector_similarity 8 2026-06-11
verify success 1 2026-06-09

Summary generated by qwen3.6-27b-prismaquant on 2026-06-09; verification: verified.

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