Evaluation of Risky Driving Performance in Lighting Transition Zones Near Tunnel Portals

Driving behavior is affected by rapidly varying lighting conditions that frequently occur in transition zones near tunnel portals. When entering a tunnel in daytime, car drivers might encounter various difficulties in keeping high performance for safety concerns: (1) Physiological issues caused by high-level glare—the adaptation of the eye requires recovery time, during which time there will be impaired vision and reduced visibility of on-road objects; (2) Psychological issues caused by visual discomfort and distraction—limited resources for performing information processing are shared by the distracting and disturbing sensation; (3) Behavioral issues caused by driving patterns of the driver and other road users—many drivers reduce their speeds when entering the tunnel; thus a car driver must react to the sudden speed change. This study investigated the records of traffic accidents on Zurich highways in tunnel areas and conducted experiments using a driving simulator. The analysis of accident records shows that the frequency of accidents increases near tunnel portals. Experimental results show that discomfort glare impairs both peripheral visual attention and motion discrimination in simulated driving tasks. In conclusion, we suggest considering tunnel portals as a key factor causing elevated risk in traffic safety. Lighting designs and road layout near tunnel portal areas should be carefully defined.