**3. The Missed Opportunity of Promoting the Re-cycling of the City Centres in the City Planning Instruments**

Has the city planning activity considered the underutilisation of the cores? Has it considered it as a problem? The theme is central for the development of Italian cities in this period of urban reuse, when a circular economy and sustainability concepts should be considered. In fact, if the cities' agenda takes on a more rational use of the land through the careful selection of projects which consume land, in particular, affecting the primary sector where there is a concern about food production, and if the regeneration of properties through physical as well as social redevelopment is considered a priority, then the historic centre of Italian cities becomes a fundamental test of adapting a stock of primary cultural, economic and social value to contemporary needs and wishes.

Even though precise numbers for a large sample of cities had not been produced until very recently [10,15,16], the abandonment of the historic centre has been perceivable for several years in Italy. Therefore, it is plausible to hypothesize city planning documents have registered it and proposed to recycle the empty stock, adopting a circular economy approach, which integrates sustainable production as well as better use of resources. To understand the reaction to the phenomenon, the research explored the city planning documents of the cities with the worst condition of not-occupied units in the most valuable part of the city, the ZTLs. The paper claims the city plans are not the main factor which caused the underutilisation, but that it was a mixture of socio-economic causes, see paragraph 4.4 and Conclusions. Therefore, the paper explores how planning activity reacts to the phenomenon where it

is most observable. The selected cases are Treviso, Modena, Udine, Vicenza where, in 2011, the empty units in ZTL reached 41.8%, 38.8%, 37.9%, 37.5% of the total units, respectively, see Table 1.

The documents are available online in the official webpages of the municipalities. The research analyzed if and how the city planning documents react to the underutilisation phenomena, see Table 2:


