*3.1. Data Gathering*

In order to collect sustainable urbanization and land-use practices from all around Europe, four main methodological steps were identified:


Throughout the project, the database underwent a number of quality control steps, performed by both the consortium partners and the Project Support Team, so it was subject to incremental fine-tuning. The online survey provided the highest number of results, generating over 160 responses. It was completed by national experts covering all the EU countries, as well as the EU candidate countries (i.e., Albania, North Macedonia, Montenegro, Serbia and Turkey) and the remaining countries of the Western Balkans (i.e., Bosnia and Herzegovina and Kosovo). The experts were selected on the basis of a variety of different profiles: academic and scientific (e.g., universities, research centers) and more administrative roles (e.g., national, subnational, local agencies). The survey was then disseminated to the ESPON national contact points and members of the monitoring committee, as well as to the members of various academic and professional associations, such as the Association of the European Schools of Planning (AESOP), the European Council of Spatial Planners (ECTP-CEU) and the International Society of City and Regional Planners (ISOCARP). At a later stage, it was also circulated to experts through the use of social media (ResearchGate, as well as the AESOP and ESPON newsletters).

The survey focused on the current state of urbanization processes in the various countries. To facilitate the experts, it started with the following definition of sustainable urbanization and land use: "Sustainable land use means using and managing land assets in a way that does not compromise the livelihood of future generations. It implies a balanced consideration of social, economic, and environmental goods and services provided by the land uses in a certain region. It also implies a careful consideration of long-term attributes of resilience and robustness of the underlying ecosystem." [31] (p. 3). After that, it required the respondents to answer a short set of questions concerning the level of sustainability of urbanization and land-use in their country, the main impediments to the latter, and some examples of interventions affecting the sustainability of urbanization and land use in the practice (Table 1). Importantly, each expert was required to identify up to three interventions responsible for influencing the overall sustainability of urbanization and land use and, for each intervention, to point out the degree of success in terms of sustainable land use.

**Table 1.** Questions composing the SUPER online survey (source: author's own on the basis of [31] (p. 3)).


#### *3.2. Data Analysis and Intervention Assessment*

After the data were collected, the intervention database was compiled and the collected interventions were further analyzed by reviewing available online documentation. The knowledge and the different skills of the consortium partners, as well as a careful analysis of the literature, helped to fill missing information and data. The interventions were then classified according to various categories and a number of analytical fields (see Table 2).

**Table 2.** Fields adopted in the analysis of the interventions (source: author's own elaboration on the basis of [31] (p. 4)).


Particularly relevant in the context of this paper is the categorization in relation to the scope and objectives of the interventions and the instruments that they adopted in order to achieve these objectives. More in detail, according to their scope and objectives, the collected interventions were subdivided as aiming either at promoting *densification* (e.g., up-zoning, infill development), fostering the *regeneration* of unused and/or problematic sites (e.g., land redevelopment, urban renewal), the *containment* of urbanization processes (e.g., green belts, urban growth boundaries), the introduction of specific *governance* models and mechanisms (e.g., cross-sectoral integration, integrated plans) or the achievement of specific *sectoral policies* (e.g., related to transport, environment or rural development). At the same time, the collected interventions were also subdivided in relation to the different types of instrument that were employed in each case in order to achieve the identified objectives, as for instance through the joint development of *visions and strategies* (e.g., strategic plans, guidance documents, etc.), *rules and legal devices* (e.g., national and regional laws), *land use regulations* (e.g., zoning, local plans), *programs* (e.g., economic incentives and other types of funds) and *projects* (e.g., single spatial transformation actions and initiatives).As shown in Table 2, the success of the interventions gathered through the above steps was then assessed in relation to both their explicit goals as well as to their ability to come to terms with the different dimensions that characterize sustainable urbanization and land-use—i.e., temporal, thematic and institutional sustainability. This assessment has contributed to develop an understanding of the factors that determine the success of an intervention or the possible reasons behind its failure, in so doing providing interesting evidence upon which to develop guidance for decision and policymakers aiming at promoting sustainable urbanization and land-use.

#### **4. Results and Discussion**

Through the described methodology, it was possible to collect and analyze as many as 235 practical examples of how, in the various European countries, actors active at the different territorial levels try to achieve a more sustainable urbanization and land-use (Figure 3). First of all, it is important to highlight that the collected sample is representative but certainly not exhaustive in describing the ongoing urbanization processes and the interventions put in place to address and steer the latter throughout Europe. In particular, whereas the database includes interventions from as many as 39 European countries, the number of interventions collected for the various countries is rather uneven and, whereas this may depend on the differential attention devoted in the various contexts to the issues at stake, it is also influenced by the localization of the consortium partners and of the respondents—with Germany, Italy and the Netherlands featuring a higher number of interventions. For the countries that were less represented in the sample, specific members of the ESPON Monitoring Committee and Contact Point were contacted multiple times in order to indicate additional potential respondents, who were then contacted and engaged, thus contributing to partially rebalancing the database. Overall, even though certain countries are better represented than others, the collected interventions provide a rich and rather comprehensive overview of the recent efforts put in place to promote sustainable urbanization in Europe.

**Figure 3.** The localization of the SUPER intervention throughout Europe (source: [25] (p. 35)).

As mentioned, each intervention was qualitatively assessed in relation to its success in promoting a more sustainable use of land. This assessment phase was based on the responses of the country experts to the online survey and further verified through desk research (e.g., analysis of scientific articles and reports retrieved through the web). By crossing the level of success with the other variables, it was possible to reflect on which goals and which types of instrument have been more successful, and to further explore the reason behind the success [3] (p. 4). In particular, as shown in Table 3, for each category of the chosen variable, the interventions show varying degrees of success in relation to their ability to achieve a more sustainable urbanization.


**Table 3.** Degree of success of the analyzed interventions in relation to their scope and goals and to the type of instrument they adopted (source: authors' own elaboration).

The degree of success is related to the interventions' ability to promote sustainable urbanization and land-use (1 = unsuccessful; 2 = scarcely successful; 3 = mixed success, 4 = almost successful; 5 = successful).

> As regards their scope and goals, the interventions that promote regeneration seem to be the most successful: in fact, the majority of interventions (62%) are graded four and five, and 28% are graded three. On the contrary, interventions that promote containment seem often scarcely successful: 14% of the interventions are graded one and two. As far as the types of instruments are concerned, programs seem to be the most effective: a high number of interventions (70%) are graded four and five, and 13% are graded three. On the contrary, projects often produce outcomes which are scarcely successful: in fact, 26% of the interventions are graded one and two.

> Starting from these first results, the next section carries out an in-depth exploration of the causes that might influence the level of success of the interventions that adopt: (i) different scopes and objectives, and (ii) different types of instruments. The results provide interesting reflections and insights for all those stakeholders who are appointed to take decisions and who are involved in the technical drafting of policies aiming at a more sustainable urbanization.

#### *4.1. Scope and Objectives of the Analysed Interventions*

This subsection looks at a number of interventions that seem to promote sustainable land use, as well as limiting land take effects. The interventions are presented in relation to their scope and objective (densification, regeneration, containment, governance and sectoral policies) and, for each of them, the effectiveness and the level of success is discussed. As pointed out in the methodology section, the majority of the examples are based on the experts' responses to the online survey. In some cases, additional sources were investigated in order to verify the information and gather further knowledge.
