Embedding sustainability into the design of street lighting

Abstract Light pollution is an increasing problem and Artificial Light at Night (ALAN) affects nature in many ways. The Norwegian Road Authorities (SVV) initiated a collaboration with the Norwegian Institute for Bioeconomy (NIBIO) and the University of South-Eastern Norway (USN) to find measures that can help reduce the negative impacts of road lighting on the environment and nature. While USN has looked more generally at sustainable lighting design and ways to reduce the negative effects of road lighting, NIBIO has focused on how road lighting affects insects. We study how the light from roads contributes to light pollution, with the final aim to know more about what measures most effectively reduce the negative effects of road lighting. In this pilot study of light levels in two transects beside a road, the results show that the light levels decreased relatively fast as the distance to the light source increased. Thus, the direct light from the road lighting might not be the most prominent addition to the light pollution in the open landscape. On the other hand, the measurements showed some light influence from the road up to around 160 meters from the road, although the levels were low. While the light was below the detection limit, the light source was visible as a point source at a very large distance. This observation addresses the question of whether organisms are influenced by the average light energy per area, or the intensity of a source as observed from a distance (irradiance vs. radiance). Additional sources of light pollution may affect the result, such as unshielded private light sources and sky glow. This project aims to find measures that can help reduce the negative impacts of road lighting on the environment and nature. We study how the light from roads contributes to different components of light pollution, like skyglow, light trespass and luminance from the light source.