Epsilon Archive for Student Projects

Abstract

Artificial light at night (ALAN) is currently posing a significant challenge to ecology and biodiversity in urban environments. The effects of ALAN, from mainly street lighting, are disruption of natural light patterns for species, contribution to light pollution, and leads to loss of dark habitats which contributes to effects on an individual- and population level and physiological changes in species. Studies have found that ALAN is expanding at a rate of 6% across Earth’s surface and affects approximately 80% of the global population on a nightly basis. While artificial light has benefits that primarily serves to improve security, perception of safety, navigation, and aesthetics for pedestrians, it frequently leads to ecological disruption. Furthermore, street lighting design has prioritized motoric traffic over pedestrian usage which has still led to excessive, uneven, and poorly optimized illumination for pedestrians. Despite ALANs increasing expansion and prevalence, research is still relatively undeveloped and there is a lack of practices and effective measures to prevent negative side effects.

This thesis addresses the need to mitigate the adverse effects of ALAN by finding the optimized design of street lighting components at different types of locations to benefit humans and biodiversity. Components have been identified as correlated colour temperature (CCT), light sources (LED, MH, HPS), illuminance levels, uniformity of light, scheduling with motion sensors, direction, and shielding. A transect walk was conducted to reveal perception of light for humans and create site analyses. The components are customized to mitigate the adverse effects on biodiversity while improving the benefits for pedestrians, specifically perception of safety, navigation, and visibility. To find a middle ground between humans and ecology, a trade-off was conducted and analysed. After trade-offs are analysed and conducted, a framework of ecological and human trade-offs in street lighting is suggested based on three different locations.