Impact of urban tunnel sidewall effect on drivers: Examining visual characteristics and driving behavior across different lanes

Abstract

Urban tunnels have been widely used as special transportation infrastructure. This study investigated the impact of the urban tunnel sidewall effect on drivers, focusing on the drivers’ visual characteristics and driving behavior as the primary research objectives. In this study, numerous real vehicle tests were conducted in the middle section of an urban tunnel, focusing on different lanes. The drivers’ visual characteristics were examined through the distribution of gaze points and fixation duration, and driving behavior was assessed using the vehicles’ lateral offset and acceleration. The drivers’ visual characteristics and driving behavior were analysed together to investigate the impact of the sidewall effect on the relationship between the visual information input and driving behavior output. A questionnaire was administered after the experiment to assess the subjective experiences of each participant. The results indicated significant variations in the impact of the sidewall effect on driver attention distribution and vehicle stability across different lanes. Drivers in the left lane were the most affected and had the highest driving risk, followed by those in the right lane; those in the middle lane had the least driving risk. Meanwhile, when drivers in the left or right lanes focus their gaze on the adjacent sidewall or shortly afterwards, the vehicle experiences a higher lateral acceleration away from the sidewall compared to other areas.