Applicability study of tunnel light source based on driving visual demand

Tunnel sections are usually traffic bottleneck sections and accident-prone locations. As a vehicle runs through a tunnel, the change of light environment will have a significant impact on the driver's physiological and psychological states, which will influence the driver’s control behavior and have a negative effect on traffic safety. At present, studies have been conducted for the improvement of tunnel lighting environment, and design methods have been proposed. With light-emitting diodes (LEDs) widely used as the light sources in tunnels, some problems appear and remain to be solved, such as the relationship between the lighting environment characteristics and visual demand of drivers. Considering the visual demand of driving, this study analyzes the applicability of tunnel light using static small target recognition studies and dynamic driving recognition studies. LEDs with different color temperatures are compared based on the experimental data of obstacle recognition distance, color rendering, degree of comfort, etc. The fit curves of the obstacle recognition distance and the color temperature in the experiments are constructed by experimental data. The experimental results show that the LED light sources with a color temperature of 4000 K~4500 K can provide a comfortable visual environment to the driver while satisfying the visual demand of driving. The conclusions are significant to enhance the tunnel lighting quality, improve the visual environment and driving safety, and reduce the energy consumption and operating costs in tunnels.