Design of Counter Beam Lights for Road Tunnels Lighting with CIE Regulations

In order to enhance driving safety, a counter beam light is proposed to achieve CIE regulations for tunnels lighting. Through appropriate arrangements of the counter beam light with conventional fluorescent lights on the ceiling of tunnel, it is demonstrated that road tunnel lighting with CIE 88:2004 regulations can be accomplished, which yields the average road surface brightness 130 nits > 105 nits (minimum regulation level), the brightness uniformity 0.89 > 0.4 (minimum regulation level ), the longitudinal brightness uniformity 0.99 > 0.6 (minimum regulation level), the glare factor 5.5% <; 15% (maximum level) and the contrast display factor 1.24 > 0.6 (minimum level) in the threshold zone.