Tactical urbanism experiences in building public spaces: lessons learned in Italy

Urban planning has changed its paradigm following the evolution of the development approach from unlimited growth to sustainable development (Daly 2014; OECD 2020). The need to save natural resources (particularly the soil), to fight climate change, to favor local economic development, have brought about a paradigm shift also in urban planning that has moved the focus of disciplinary interest from the indefinite expansion of urban suburbs to the regeneration of the existing city both in its physical spaces and in its society (Van der Zwet and Ferry 2019; EC 2020; Beer and Clower 2019; Medeiros and van der Zwet 2020). In urban regeneration processes, the degraded spaces and the residual voids of previous expansion cycles have become the privileged spaces for new projects (Magnaghi 2005). Social reasons for changes in urban planning have been added to the environmental ones, linked to the contemporary demographic dynamics of most Western nations experiencing a phase of demographic contraction. The shrinking cities phenomenon and its consequences have been explored in a large international literature (Oswalt and Rieniets 2006; Pallagst et al. 2009; Audirac and Alejandre 2010; Camarda et al. 2015). After reductions in mortality, fertility not only decreased but reached values lower than those of generational replacement (which corresponds to approximately two children per woman). The European continent, as a whole, has collapsed below this threshold since the second half of the 1970s. The current European Union figure is just over 1.5. The United States managed to remain close to the replacement value for longer, but in the last decade it has suffered a significant reduction (United Nations 2022). Naturally, demographic dynamics are very different for nations like China or India. Even more than in the past, growth rates between areas of the world and between generations have never been so divergent. Such processes of ecological and demographic transition have forced development models to change with obvious and decisive consequences also in urban planning. Urban regeneration of existing cities is the main objective of urban planning and the main tool of urban design. But how should urban regeneration processes be carried out? There are project tools that allow “planning by doing” as Campos Venuti (1978) elaborated in another historical context, anticipating and verifying the possible consequences of design choices and allowing the inhabitants to realize this directly by experimenting with the solutions without having to read difficult three-dimensional models or to be anxious about spending a lot of public money without being able to go back on the choices made. There have been multiple ways of defining possible answers to these questions which have taken on different names often indicating very similar interventions such as: “do-it-yourself” (DIY), “pop-up”, “guerilla”, and “tactical urbanism”. All these practices (many of them already discussed by Lydon 2011; Lydon and Garcia 2015; and Bishop and Williams 2012) were informal and temporary urban design governance actions, very often related to bottom-up processes of community empowerment (a panorama of these European informal urban design governance practices has been made by the Urban Maestro organization,1 summarized and discussed by Carmona et al. 2023), and used as urban regeneration catalysts (Oswalt et al. 2014). With the spread of these experiences throughout the world, institutions have also begun to realize that these types of interventions, especially if placed within broader urban regeneration strategies, might no longer be promoted only by inhabitants or autonomous groups of interests (often to counteract the inertia of institutions in tackling the degradation of some places), but also directly by the institutions themselves. In this new institutional context, tactical urbanism (TU) has come to be regarded as a regeneration tool capable of providing innovative answers to pressing problems in cities and urban areas.