Under the current lighting standard, a vehicle’s headlamps are not taken into consideration in the visibility evaluation for obstacles on the surface of a road based on the tunnel lighting.
In this paper, we quantitatively evaluate the visibility for obstacles based on the total power revealing properties, while considering a vehicle’s headlamps and the tunnel lighting. As a result, in the case of a symmetric lighting system, the visibility of obstacles on the road based on the headlamps and tunnel lighting decreased at a point in vertical illuminance that was lower for a higher average road surface luminance. In contrast, a pro-beam lighting system showed that the obstacle visibility scarcely changed even if the headlamps were added, and that it is the effective in the terms of coordination of tunnel lighting and headlamps.
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