Objective: The service status of tunnel lighting has an important impact on driving safety. Existing research mainly discussed the impact of a single evaluation indicator of lighting service status on driving safety and paid less attention to the impact of multiple evaluation indicators on driving safety.
Methods: In this research, field tests of tunnels in three speed scenarios and 52 service scenarios are completed. DIALux software was selected to simulate more intensive illuminance, which could be used to calculate U0, U1, qc, and C. Using U0, U1, qc, and C as explanatory variables, and applying the normalized visual recognition results as explained variables, ordinary least squares regression (OLS) was performed to calculate the influence weight of each explanatory variable on driving safety.
Results: The results show that the four independent variables occupied different weights under different working conditions. However, on the whole, U0 and U1 occupied a greater weight. The weight of C lies between qc and U0, and U1 and qc occupied the smallest weight in all scenarios. Locally, U0 was greater than U1, with the exception when the illumination attenuation value was 70%.
Conclusions: The influence of the total uniformity of the road surface luminance and longitudinal uniformity of the road centerline luminance on driving safety was significantly greater than the influence of the contrast revealing coefficient and luminance contrast C on driving safety. When the luminous flux was attenuated to 70% or less and when the number of failed lamps was at least four, the lighting quality would be significantly reduced, which would substantially affect driving safety.
Keywords: Tunnel lighting; driving safety factor; safe driving; service status.