Optimizing Intersection Design: Insights From Older Drivers’ Physiological Responses and Gap Acceptance Behavior at Signalized Left Turns

Abstract

Aging populations pose significant challenges for transportation safety at complex intersections. This study investigated gap acceptance behavior of older drivers at left-turn signalized permissive intersections using a driving simulator with 40 participants (20 older, mean age $77.95~\pm ~5.79$ years; 20 younger, mean age $25.95~\pm ~1.66$ years). Participants experienced varying traffic volume levels, queue length, and pedestrian presence. Physiological responses, such as electrodermal activity (EDA) and heart rate variability (HRV), provided insights into drivers’ internal states during decision-making. The results showed that older drivers required longer gap acceptance times compared to younger drivers. Experimental factors like higher traffic volumes, longer queues, and pedestrian presence significantly impacted gap acceptance and led to more conservative decisions. Additionally, higher EDA levels correlated with longer gaps, indicating stress during decision-making. HRV showed a modest yet significant correlation with gap acceptance in older drivers. This suggests that changes in HRV affected their decision-making process, though the influence was weaker than EDA. Significant interactions between traffic volume and queue length and a three-way interaction with pedestrian presence emphasized the complexity of these decisions. Motion sickness susceptibility was also significantly correlated with gap acceptance. These findings contribute to improving road design and driver assistance systems, promoting safer intersections for older drivers.

Keywords

• Gap acceptance behavior
• aging
• driving simulator
• traffic dynamics
• permissive left-turns
• physiological responses