Simulation experiments on counter beam lighting in highway tunnel

Counter beam lighting was introduced as well as transverse symmetrical lighting and longitudinal symmetrical lighting. Simulation experiments were carried out by using DIAlux lighting software for the above three lighting methods. The results show that counter beam lighting is more reasonable to be adopted in the tunnel entrance zone because its threshold increment of disability glare is greater. Counter beam lighting can improve the background luminance of the obstacles and lighting efficiency compared with transverse symmetrical lighting and longitudinal symmetrical lighting. Therefore, tunnel lighting energy-saving can be achieved by reducing the road luminance demands and luminaries power. Longitudinal symmetrical lighting is conducive to the large luminaries spacing in the tunnel internal zone; so power consumption can be reduced by decreasing the number of luminaries used. Tunnel walls are unsuitable to pave with smooth or bright material. Installation height of the luminaries has less effect on counter beam lighting.