Evaluating the safety of freeway tunnels based on the driving behavior and physiological responses: a route familiarity perspective

Long freeway tunnels are vital for sustainable transportation, reducing travel distances and environmental impact. Ensuring their operational safety is key to achieving these sustainability goals. While driver behavior and physiological responses heavily influence tunnel safety, the impact of route familiarity, especially on sustainable safety measures, remains under-explored. This study evaluates how driver route familiarity affects driving behavior and physiological responses in China’s Yanzidong tunnel to optimize sustainable and safe operations. A field experiment with 32 familiar and un-familiar drivers collected data on driving behavior (average speed, acceleration) and physiological responses (heart rate, skin conductance) across entrance, median, and exit tunnel sections. Principal Component Analysis (PCA) developed a quantitative risk score for each section, reflecting driver safety and comfort. Key findings revealed familiar drivers exhibited stable acceleration and heart rates but drove at higher speeds with generally elevated heart rates. Unfamiliar drivers displayed greater fluctuations in acceleration and heart rate, alongside lower average speeds and heart rates. Risk analysis showed familiar drivers faced higher risks in the median section, linked to over-confidence and speed, while unfamiliar drivers experienced higher risks at entrances and exits due to higher cognitive load in an unfamiliar environment. These insights are crucial for developing targeted management strategies that address the distinct challenges of varying driver familiarity. Such strategies will significantly enhance tunnel safety and comfort, thereby improving the overall sustainability and effectiveness of these critical transportation infrastructures.