The impact of nighttime car body lighting on pedestrians' distraction: A virtual reality simulation based on bottom-up attention mechanism

Car body lighting (CBL) is increasingly being used to enhance brand recognition and consumer appeal. However, due to the finite attentional capacity of individuals, such salient stimuli may distract people from safety-related tasks, potentially leading to traffic crashes. While existing research on external lighting of vehicles predominantly examines how external human-machine interfaces (eHMI) characteristics affect communication efficiency, there are few studies exploring the relationship between decorative lighting parameters and distraction. This study aims to investigate the impact of bottom-up factors of car body lighting, including location, color, and brightness, on top-down attention of pedestrians within traffic environments to ensure traffic safety. Eighteen participants were recruited to complete a detection-response task in a virtual reality environment, where vehicles with car body lighting approached on a two-way road under nighttime conditions. The study compared the effects of CBL at six different locations (ranging from the roof to the grille), two colors (cyan and white), and two brightness levels (assessed by contrast), on pedestrians' subjective evaluations, visual behaviors, and response time. The results revealed that area-type CBL positioned at the grille and lighting around the windshield were perceived as significantly more distractive compared to other locations. Moreover, the effects of the color were found to be dynamic, influencing subjective ratings and eye movements depending on the location and brightness of the CBL. Finally, an increase in brightness leads to a significant increase in perceived distraction and response time. These findings provide new supplements on how dynamic stimulus outside the focus of attention can disrupt the top-down attention processes. This study offers new insights for assessing the impact of additional lamps, and establishes a foundation for developing relevant standards.