Effects of Different Security Lamps on Pedestrians Subjective Responses of Luminous Environment in a Residential Street

Abstract

Outdated security lights installed in residential district are vulnerable to safety, cause light pollution, and consume excessive energy. To solve these problems, the City of Seoul launched the Luminous Environment Improvement Project that changes a light source of residential security lights from sodium lamps to LED lamps as the Light Pollution Prevention Law Based on Artificial Lighting was enforced. Little study has been devoted to change on luminous environment and perception resulting from replacement of security lights in residential districts. Therefore, the purpose of this research is to analyze change in pedestrian perception and improved LED effects after high pressure sodium lamps were replaced by LED lamps in the existing residential districts. For pedestrian perception, questionnaire assessment was used to assess perceived danger, visual accessibility, perceived natural colour of objects, and perceived light ambience. In addition, illuminance and luminance on roads were physically measured to determine LED effects. Comparative analysis was done between sodium lamps and LED lamps were on lighting environments by measuring road surface horizontal illumination and luminance, elements of which are defined in KS A 3701 Lighting for Roads and KS C 7658 LED Luminaries for Road and Street Lighting (Korean Industrial Standards). The questionnaire assessment was analyzed with SPSS Ver.21 to evaluate internal consistency on the questionnaire and mean difference of each item among survey groups for lighting environment of sodium lamps and LED lamps. As a result, LED lamps, compared with sodium lamps, were more than three times higher in horizontal illumination and more than double the average luminance. Statistically significant difference was also demonstrated in perceived danger, visual accessibility, perceived natural colour of objects, and perceived light ambience. Given the positively improved lighting environment with LED lamps better than existing sodium lamps, revealed from the survey results, it is considered that LED lamps will set up road luminous environment with enhanced safety and visibility for pedestrians in residential areas with high number of pedes