**Table 2.** Table comparing the city plans.

The reading focused on some key terms: Underutilization, heritage, centre, conservation, sustainability, sustainable development.

The research analyzed the spatial planning documents because they are the manifesto of the public and the official position assumed by the local governments in recent years: The research produced an exegesis of the texts and maps which compose the city plans as a critical assessment able to decipher urban planning stories and their coherence with the current reality.

The analysis shows the planning documents in force only recently started to acknowledge the problem and only a few policies were proposed to actively revitalize the centre. The research assumes it as evidence that the concept, tools and procedures of planning and regulatory practice—matured over the course of decades of economic and demographic growth—should be updated to be able to react to the structural changes in Italian society and economics and to the new—however, not really new–urban dynamics and mega-trends.

### *3.1. City of Treviso, Acknowledgement of the Phenomenon in the Bigger Picture but Late and Limited Action*

Treviso, Veneto Region, has 81,000 inhabitants and 1600 inhabitants in the 24 ha of the ZTL in the the heart of the city centre [25]. Treviso has a strategic plan, approved in 2015 (Piano di Assetto del Territorio—PAT) and an action plan, adopted in 2018 (Piano degli Interventi—PI) [28,29].

PAT registers some cases of underutilized or unutilized building stock, but does not acknowledge the phenomena of abandonment of the historic centre, which was already evident when the drafting of the plan started. The document which defines how much the city can grow in relation to what already exists classifies only the un-let units as the unutilized stock, assessing it to be 8.5% of the total availability, and declares it is non-recoverable and, therefore, not relevant to answer the present and future demand [30,31].

Despite the general goals stated—intensified requalification of the existing stock and historic and cultural identities as strategic assets for economic growth—and despite the population decrease by 2.16% in the municipality and by 11% in the city centre between 1991 and 2011, PAT foresees an increase in population of 14,500 units, almost 17% of the existing population, and urbanizes new areas to accommodate this increase.

In the strategic actions for sustainable urban regeneration (ambiti dei programmi complessi) the historic centre is not included, even though its requalification would require minor urbanization investments compared to the targeted abandoned large areas, twentieth-century complexes in peripheral areas that no longer respond to any use; these are very evident to the inhabitants and represent a problem for the local governments, while the centre clearly does not.

More attention to the city centre is given in the action plan—PI adopted in 2018, see Figure 2. It claims the need for actions for containing land consumption and revitalizing the city centre, allowing more flexible uses, multistory parking in dismissed structures, public-private use of parking. PI almost halves the amount of new residential developments and pursues the return of inhabitants to within the perimeter of the historic centre, and in considering the centre as an asset, PI also mentions the tool for temporary reuse introduced by the regional legislation for the containment of land consumption: To activate a process of regeneration of the abandoned or unused building stock with tactical interventions, waiting for a more substantial and definitive restructuring operation [32,33]. PI is a step forward because it clearly identifies the problems associated with the city centre. However, this action is late and limited considering the significance of the issue.

### *3.2. City of Udine, neither Acknowledgement nor Action*

Udine, Friuli Venezia Giulia Region, has 98,000 inhabitants and 1700 inhabitants in the 38 ha restricted traffic zone [25]. The city planning documents approved in 2012 (Piano Strutturale—PS and Piano Regolatore Generale Comunale—PRGC) do not acknowledge the abandonment of the city centre and, therefore, do not give it a role in the actions for future sustainable development; generally, the plans give a representation of a city without severe problems [34].

Considering the slow demographic trends, PRGC reasonably defines the population in 2025 as 101,666 inhabitants and defines the normal un-let units in the city at 8.8%. Nevertheless, to answer the diverse housing needs, the plan adds 12,270 units to the existing ones, corresponding to a total population of 117,050 inhabitants (+17%). To answer this future demand, the Piano Regolatore Generale Comunale does not specifically plan the requalification of the stock in the centre [35,36].

**Figure 2.** Excerpt from the Piano degli Interventi—PI of the city of Treviso, 2018; zoning and regulations of the historic centre.

PRGC mentions the goal of enhancing livability and re-qualifying the most valuable heritage to increase its attractiveness, but proposes some remarks that are unconnected to specific actions. The main idea, which shows some worries about the centre, is to consider the centre as a "natural shopping mall" in order to compete with the extremely successful shopping malls in the periphery, which have been massively draining customers and visitors since the 1990s. This idea proposes to reinforce the core without exploiting its identity, but adopting a model produced for different urban contexts. For this goal, PRGC proposes to enhance the public open spaces for pedestrians, mostly with projects of connections in the centre itself. This strategy seems to be out of focus, as the historic centre of Udine was designed and has always been a place for pedestrians and these connections are already there; in contradiction to this direction, the new local government in 2018 has approved to reintroduce car traffic in the ZTL.

The structural plan confirms the traditional interpretation of the territory around the Udine as a polycentric structure where the city is the most relevant core for its history and extraordinary urban quality; the plan also confirms Udine's historic centre as the centre of this territory, when in reality, it is in a crisis of representation and vitality with a rate of 39% of underutilized housing units in 2011, a 70% reduction in local units of public institutions, and an 8.30% decrease in inhabitants.

### *3.3. City of Modena, Early Acknowledgement of the Phenomenon and Recent Attempt to Promote Actions*

Modena, Emilia Romagna Region, has 179,000 inhabitants and 8900 inhabitants in the 72 ha restricted traffic zone [25]. The structural plan, approved in 2013 (Piano Strutturale Comunale—PSC), reacts to the underutilisation phenomena impacting the historic centre, a problem studied since 2006 [37,38].

PSC describes the constant transformation of the centre and focuses on two groups of actions, the first related to accessibility, rest areas, garages—declared as very relevant—and the second, to re-generation. For the first, the plan refers to further studies. For the second, it proposes to promote cultural and recreational activities, as well as commercial ones, and also refers to further studies for understanding the residents' needs. The plan connects the requalification of some areas with reduced land consumption, referring to further specific policies [39].

The action plan approved in 2014 (Piano Operativo Comunale–POC and the related Regolamento Urbanistico Edilizio–RUE) fails to go one step further, that is to say, it neither specifies actions nor adds studies but adopts the usual and well-established practice for conservation: Almost every building in the city centre is subject to restrictive regulations (i.e., the Italian law defining the types of intervention: law 456/1978, art. 31), see Figure 3. In addition to these usual restrictions of transformation, increasing the dimensions of the buildings is always prohibited, as well as the change in use from shops, bars and laboratories into garages [40].

**Figure 3.** Excerpt from the Regolamento urbanistico edilizio—RUE of the city of Modena, 2013; zoning and regulations of the historic centre.

PSC gives a definition of the historic centre corresponding to the traditional idea of its values: The centre is a reference for the development of the local community, mostly for its public spaces and services which allow the inhabitants to be a community. According to this definition, the plan acts contradictorily: On one hand, it does not claim the recently diminished role, on the other, it includes the centre in the areas where public services are lacking, a new element to remark upon because the centre has traditionally been the place where services are concentrated.

Even if the plans in force do not propose an innovative approach to deal with the problems of the city centre, the revitalization of the historic centre with active policies has been discussed at a higher political level since the first months of 2018 and a new POC was adopted at the end of 2018: Facilities for the residents, improved accessibility and parking areas, economic support and touristic promotion are the solutions proposed.

### *3.4. City of Vicenza, Some Acknowledgement and Some Action Limited in Purpose*

Vicenza, Veneto Region, has 111,500 inhabitants and 3019 inhabitants in the 50 ha restricted traffic zone [25]. The strategic city plan for Vicenza, approved in 2010 (Piano di Assetto del Territorio–PAT), declares a "crisis of identity" of the city centre for some of the reasons explained by the present research based on the interpretation of the Census Data: New, poor immigrants, weak public services, poor commercial supply and inadequate recreational areas [41,42]. To cope with this crisis, PAT suggests to improve cultural, recreational and shopping attractions and tourism and considers the city centre as an "open-air museum". The 'museumification' of the historic space is coherent with the age of the plan

for the city centre in force (Piano particolareggiato per il Centro Storico—PCS), which dates back to 1979 (but was drafted in 1969, see Figure 4), even though it was partially updated in 1988 [43].

**Figure 4.** Excerpt from the Master plan of the city of Vicenza, 1969; zoning and regulations of the historic centre.

Similarly, PAT declares that the city centre must again become the place of high-quality residences, because the migrant and mobile population, that is increasingly occupying it, will cause its decay. PAT does not recognize in the new inhabitants a possible way to revitalize the centre, nor does it interpret the city centre as one of the "eco-neighbourhoods" which it defines their high-density and potential for regeneration: The main concern about the centre remains the conservation of its beauty and characteristics.

PAT promotes sustainability as a principle for a general urban re-structuring, and it stresses dwelling units must be obtained by re-using and re-qualifying the existing stock. However, the action plan approved in 2013 (Piano degli Interventi—PI) plans to accommodate only 600 of the future foreseen 14,269 new inhabitants in the city centre, while the present research found 2097 empty units potentially available [44].

Vicenza can be considered a paradigmatic example of the well-established approach to conservation in planning—resulting from an extensive technical, as well as conceptual theoretical reflection and definition of practices which goes back to the beginning of the XX century [7,8,45,46]—consciously applied to deal with new conditions without updates or reframed regulations.
