Solar accessibility in high latitudes urban environments: A methodological approach for street prioritization
Matteo Formolli, Peter Schön, Tommy Kleiven, Gabriele Lobaccaro
Abstract
Streets are the fundamental public space where people move and socialize within cities. Their attractiveness depends on a wide variety of factors, with solar accessibility emerging as crucial in cold climates to guarantee thermal comfort and stimulate the presence of people. This article presents a methodological approach to evaluate and prioritize streets based on solar accessibility in high latitude urban environments (Trondheim, Norway). For this purpose, two novel solar indices, based on hours of direct sunlight and solar irradiation metrics, are introduced, while a calibrated pedestrian model is applied to prioritize streets for solar accessibility based on high predicted pedestrian flows. The results highlight generally favorable solar accessibility in the summer and over the entire year, especially for streets with high predicted pedestrian flows. Urban morphology variables (i.e., street width and building height) impact solar accessibility during mid-season, whereas tree coverage has a significant effect during summer. The presented approach provides public authorities and urban planners with a descriptive and prescriptive planning instrument to prioritize streets for adequate solar accessibility. Moreover, the findings of this study can support the development of urban regulations, policies, and strategies (e.g., street profile changes, management of trees, demolitions, and use of reflective materials) aiming at conserving and restoring solar accessibility in outdoor public spaces over extensive urban areas.