Pedestrian visibility at night: The effect of solid state streetlights

Abstract

This study examines the effect of different types of lamps on pedestrian night time visibility. Detection distance was used as a measure of visibility. The detection distance was measured in the presence and in the absence of on-coming car headlamps in an unlit street. Subsequently, the street was lit using metal halide, high-pressure sodium or LED luminaires. A pedestrian who changed his clothing colour randomly was used as a target. The results showed that the detection distance on the unlit road was 52% shorter in the presence of on coming car headlamps than when the oncoming car headlamps were off. A person wearing black clothing was harder to see and their mean detection distance was 60% less than when the observer was not dazzled by the oncoming car headlights. When the street was lit, the detection distance was doubled. The mean detection distance using LED lamps was statistically similar to that obtained using metal halide lamps, both of which were better than the detection distance obtained under high pressure sodium lighting.