Dark Adaptation in Urban Environments: An Innovative Design Framework for Pedestrian Lighting

Outdoor lighting has mainly been approached as an engineering subject throughout its history. The current urban lighting requirements are established upon factors which mainly refer to motorised traffic dynamics. As a consequence, excessive lighting levels are found in the city environments with a negative impact on the human as well as the environmental sphere. By synthesising scientific knowledge on human visual system and outdoor lighting theories, this research seeks to formulate strong arguments to point at the lack of human scale in the contemporary practice and to question the adequacy of the standard requirements for human vision in nighttime settings. The knowledge gained from scientific studies and ongoing research shows how the nighttime visual experience of pedestrians is still an untapped dimension, unveiling the lack of defined guidelines and methods to approach the design of urban lighting through the lens of this target. With a focus on soft mobility, the aim of the study is to address dark adaptation as a human factor in the design of urban lighting and to provide evidence on the human eye's ability to perform in dim conditions. Important findings from the literature review were used as requirements to formulate a methodology to approach the design of pedestrian lighting in urban environments. Strong conclusions could be drawn on the figure of dark adaptation and important lighting requirements were identified to facilitate this process in the condition of soft mobility. Even though further research and experimentation are required to implement dark adaptation in the design of urban lighting, this paper's goal is to open up new perspectives in the field, shaping the vision for the future of cities with reduced urban illumination.