# Indicators as Mediators for Environmental Decision Making: The Case Study of Alessandria
## 1 Introduction  
The United Nations (UN) Sustainable Development Goals (SDG) includes the enhancement of inclusiveness, safety, resiliency, and sustainability of cities and human settlements (SDG-11), with a specific target placed on the accessibility of green and public spaces (Target 11.7) [1]. To monitor actions, threats, and achievements related to this goal, UN-Habitat has developed a Global Public Space Program (GPSP), which stands on an inclusive definition of public space as <<all places publicly owned or of public use, accessible and enjoyable by all for free and without a profit motive>> (_Charter of public space_, Art. 1.6) [2]. Starting from this general statement, the GPSP guidelines recognize that the streets are the typology of space which most fulfils these criteria [3] (p. 27), defining the \"character of a city\", and generating a \"connective matrix>> that <<forms the skeleton of the city upon which all else rests\" [1] (p. 3). Streets are defined as the kind of public spaces that guarantee the essential urban function of mobility by breaking the physical limit of buildings. In this broad sense, this category includes avenues and boulevards along with squares and plazas [3] (p. 27). In addition to their connective function, the streets play a fundamental social role, being aggregation places both in everyday life and for extraordinary events. Consequently, their aesthetic/environmental quality has a strong impact on the general _healthiness_ ofpeople [4; 5; 6]. Furthermore, *they can be defined as multi-use public spaces*[3] (p. 27) with high transformative potential. In 2020, in a note related to the COVID-19 pandemic, the UN-Habitat stressed the key role of public spaces, *whether to limit the spread of the virus or to provide ways for people to relax or carry out their livelihood*[7], emphasizing their multi-functionality and adaptability. The design of public spaces is also a core part of *sustainable urban development*[8] (p. 24). Adapting to the changing climatic conditions links the maintenance of the usability of public spaces to the optimization of their bioclimatic performances. For example, the growing temperatures increase the phenomenon of Urban Heat Islands (UHI), with documented consequences on human health [9; 10; 11]. Thus, public spaces' management, maintenance, and design have to deal with their complex nature, involving the built, social, and natural environment, and considering tangible and intangible layers, physical components, temporary uses, and symbolic and identarian meanings. Consequently, it requires adequate multidisciplinary and systemic approaches and methods to integrate contributions from different fields of study, providing decision-makers with holistic and synthetic development scenarios. This need for mediating between decision making and the complex nature of the urban environment dates back to the foundation of urban planning as a discipline; however, ways of realizing this link have changed due to technological evolution and epistemological paradigm shifts. In the first half of the 20 th Century (except for some pioneering earlier studies), the language of mathematics started to be more systematically used for describing the city. At the intersection between economy, geography, and social sciences, in the framework of location theory, several models have been developed to analyze the relationship between economic activities and their spatial position, providing strategies to select locations for maximizing profits [12] (p. 4). This quantitative approach, along with the positivist idea of the urban space as a measurable object, has been progressively criticized and revised in the second half of the 20 th century, in a qualitative revolution grounded in the Structuralist cultural context. The city appeared in its complexity [13], leaving behind the Renaissance and Modernist illusion of an ordered system.