Methods to Reduce Flicker and Light Pollution of Low-Mounting-Height Luminaires in Urban Road Lighting

Abstract

Current low-mounting-height luminaires (LMHLs) have low effective luminous flux, high surface brightness, and many stray lights, resulting in high energy consumption and light interference, and the flicker effect may threaten driver safety. Currently, the flicker effect in LMHL lighting has been relatively poorly studied. However, in prior research, a Flicker Index (FI) quantification model was developed. In this study, we have modified the FI model to incorporate visual persistence, visual masking, and driving speed of the driver, and proposed a dynamic energy ratio model for quantifying flicker effects. The notion of effective luminous flux in road lighting was introduced, revealing that the reasons for high energy consumption, severe light pollution, and strong flicker effects in regular LMHLs were low effective luminous flux and high surface brightness. We recommend a low-mounting-height lighting technique that functions in both forward and reverse directions, which can significantly enhance the effective luminous flux of lighting fixtures, reducing stray light. The lighting fixtures created were tested on a road. The findings suggest that the energy consumption of both forward and reverse lighting fixtures is only 40% of the international standard requirements, resulting in 81% more energy savings than in existing LMHLs. The surface brightness of forward and reverse lighting fixtures is only 1.18 cd/m2, which is equivalent to 0.001% of the surface brightness of existing lighting fixtures. This indicates that 99.89% less invalid light is projected into the environment, indirectly reducing light pollution. Additionally, the flicker index of these fixtures is only 2% of that of existing lighting fixtures, reducing the impact of the flicker effect on drivers. This study provides insights into quantifying and mitigating the flicker effect in LMHLs, as well as presenting novel approaches and strategies for enhancing the efficiency and reducing light pollution of streetlamps.