Speaker
Description
Introduction and Research Problem
Temporary urban interventions have become an increasingly common way of testing changes in public space before committing to longer-term forms of urban transformation. Their appeal lies partly in their reversibility: a proposed spatial arrangement can be introduced, observed in use, discussed with local actors, and modified before a more permanent decision is made. Recent research has consequently considered temporary interventions not only as short-term spatial projects but also as forms of urban experimentation through which experience and feedback can inform subsequent planning decisions (Nogueira et al., 2026; Stevens et al., 2024).
The growing literature on temporary urbanism, however, also points to different possible trajectories after an intervention. Some interventions become permanent, while others are modified, removed, repeated elsewhere, or maintained through social and organizational arrangements. Research on temporary open-space projects has shown how temporary interventions can function as tests or proofs of concept for permanent projects (Stevens et al., 2024). Other studies have examined experimentation as a means of influencing longer-term planning and have drawn attention to learning, adaptation, and changes in planning practice (Nogueira et al., 2026; Schreiber, 2025).
These developments raise an important analytical problem. A change that persists after an intervention is not necessarily evidence that the planning system has learned from it. Physical permanence may reflect public demand, political priorities, technical feasibility, funding, or administrative decisions. Likewise, the adoption of an idea or method in a later project may indicate that experience has been transferred, but it does not necessarily demonstrate a durable change in the way a planning system observes, evaluates, decides, or acts.
This issue is particularly relevant to Milan’s Piazze Aperte programme. The programme has attracted considerable attention as an approach that combines temporary spatial interventions with experimentation, civic collaboration, and subsequent permanent transformations. Bruzzese (2026) has examined the programme in terms of governance transformation, collaboration, administrative adaptation, and the institutionalization of experimental planning practices. The purpose of the present study is therefore not to establish whether Piazze Aperte generated institutional or organizational effects. Rather, it asks a more specific question about how such effects should be interpreted as evidence of learning.
The study focuses on the period after the initial intervention and asks: After temporary urban interventions, what forms of change persist, how is experience transferred beyond the initial project, and under what conditions can these changes be interpreted as evidence of planning-system learning?
Conceptual and Theoretical Framework
The analysis distinguishes three concepts that are often brought together in discussions of temporary urbanism: continuity, transfer, and planning-system learning.
Continuity refers to what remains after a temporary intervention. It may be spatial, social, organizational, or programmatic. Spatial continuity concerns the persistence of physical elements or spatial configurations. Social continuity concerns continued use, activity, appropriation, or participation. Organizational continuity refers to relationships, roles, management arrangements, or collaborative practices that continue after the intervention. Programmatic continuity concerns the retention of methods or procedures within a wider programme.
Transfer is different. It occurs when an experience, idea, knowledge, or method moves beyond the initial project and is subsequently used in another project, programme, or context. A project can therefore have continuity without transfer, and experience can be transferred without the original intervention itself becoming permanent.
Planning-system learning represents a further step in the analysis. It refers to a relatively durable change in how the planning system observes, evaluates, decides, or acts that can be meaningfully connected to experience generated through the intervention. This definition is deliberately narrower than the broader notion of learning. A project team may learn from an intervention by changing its design in response to monitoring or public feedback. Such a change is evidence of learning within the project, but it does not by itself demonstrate learning at the level of the planning system.
The framework therefore does not assume a fixed progression from temporary intervention to permanence, transfer, institutionalization, and learning. Different interventions may follow different paths. Institutionalization can provide particularly strong evidence of system-level learning when an experimental approach becomes embedded in procedures, organizational arrangements, evaluation practices, or formal planning mechanisms. It is not, however, treated as a necessary stage of every learning process.
The central proposition is that spatial permanence is neither a sufficient nor a necessary condition for inferring planning-system learning. Permanence is not learning, continuity is not transfer, and transfer is not automatically system learning. Conversely, the absence of physical permanence does not establish that learning did not occur.
The framework is consequently diagnostic rather than confirmatory. It traces possible relationships between intervention, experience, feedback, adaptation, continuity, transfer, and durable change in planning practice. None of these relationships is assumed to be automatic. Each requires evidence. In particular, the farther an inference moves from the intervention itself, the stronger the evidence required to attribute the observed change to the experience generated by that intervention.
Methods
The study uses a qualitative comparative design and process tracing to examine post-intervention trajectories. The unit of analysis is the trajectory following the intervention rather than the public space considered in isolation. This makes it possible to examine both what remains within the original project and what, if anything, moves beyond it.
Four interventions from Milan’s Piazze Aperte programme were selected: Piazza Dergano, Piazza Angilberto II, Piazza Belloveso, and Piazzale Bacone. The four cases were purposively selected to capture variation in post-intervention trajectories, including differences in spatial permanence, social and organizational continuity, adaptation, and programme-level development. Case selection was not based on evidence of planning-system learning.
For each case, the analysis traces the available evidence from the experimental intervention to subsequent developments. Particular attention is given to evidence of testing and experience, monitoring or feedback, modification of the intervention or its final design, continuity after implementation, transfer to other projects or programme practices, and changes that may indicate a more durable transformation in planning practice.
The analysis distinguishes different levels of evidentiary strength. Strong evidence is based on an explicit connection between the experience of the intervention and a subsequent change. Moderate evidence is supported by several temporally ordered sources that indicate a process but do not establish direct attribution. Weak evidence rests mainly on sequence, similarity, or coincidence. Where the evidence does not adequately support a relationship, the relationship is treated as unestablished.
The analysis also considers alternative explanations for subsequent changes, including policy priorities, funding, technical feasibility, public demand, political pressures, organizational capacity, and regulatory or administrative changes. This is essential when assessing whether a permanent transformation or later planning decision can reasonably be attributed to learning generated by a temporary intervention.
Results
The four cases reveal different post-intervention trajectories.
In Dergano, the temporary intervention was explicitly treated as an experimental phase. Monitoring of its effects was used to identify corrective and complementary measures for the definitive configuration. The evidence therefore provides a strong basis for identifying learning within the project: experience generated through the intervention informed subsequent modification. The case also shows strong spatial continuity and contributes to evidence of the wider development of the Piazze Aperte approach. However, the available evidence does not allow the learning demonstrated in Dergano to be attributed directly to a transformation of the planning system as a whole.
Angilberto II presents a similar relationship between experimentation, feedback, and subsequent permanent intervention. Observations and feedback associated with the temporary configuration informed improvements to the definitive project. This provides strong evidence of learning within the project and of spatial continuity. Evidence that the experience of this individual intervention was subsequently transferred in a way that can be clearly distinguished from broader programme development is more limited.
Belloveso offers another clear experimental trajectory. The temporary intervention preceded permanent redevelopment and served to test a new spatial configuration before the definitive project was implemented. The subsequent transformation therefore provides strong evidence that experimentation informed the development of the project. Spatial continuity is particularly clear in this case, as is the connection between the temporary intervention and the later permanent arrangement. The evidence does not, however, establish that Belloveso alone produced a durable change in planning practice beyond the project.
Bacone follows a different trajectory. The case provides evidence of continued social and organizational activity after the intervention, including collaboration, care, and community involvement. It therefore demonstrates a form of continuity that cannot be captured by physical permanence alone. At the same time, the evidence concerning the longer-term realization of the full structural redevelopment requires caution. Bacone consequently illustrates the analytical importance of separating physical permanence from social and organizational continuity.
Taken together, the cases provide stronger evidence for learning within individual projects and for transfer at the programme level than for planning-system learning attributable to any particular intervention. The broader Piazze Aperte programme demonstrates the continuation and expansion of an experimental approach, but the contribution of an individual intervention to system-level change cannot be isolated with sufficient confidence from the available evidence.
Discussion and Conclusion
The comparison suggests that the long-term significance of temporary urban interventions cannot be assessed simply by asking whether the temporary arrangement became permanent. In Dergano, Angilberto II, and Belloveso, the strongest evidence concerns the use of experience and feedback to modify or consolidate the same project. Bacone, by contrast, draws attention to social and organizational forms of continuity that may persist independently of complete physical permanence.
These differences matter for how learning is inferred. Physical persistence is evidence of continuity, but not by itself of learning. The use of experience beyond the original project can provide evidence of transfer, but transfer alone does not demonstrate a durable change in planning-system practice. Institutional or organizational change may constitute stronger evidence of system-level learning, but only where a credible connection to the earlier intervention experience can be established.
The contribution of the study lies in making this inferential problem explicit. Rather than assuming that permanence, repetition, transfer, or institutional change demonstrates learning, the analysis asks what evidence connects an intervention to a subsequent change and how far that evidence permits the inference to extend. The farther the inference moves from the intervention itself, the stronger the evidence required for attribution.
This perspective shifts attention from the simple question of whether temporary interventions endure to the broader trajectories that follow them. What remains may be spatial, social, organizational, or programmatic. What moves beyond the initial project constitutes transfer. What changes durably in the ways a planning system observes, evaluates, decides, or acts may constitute system learning. These should not be treated as interchangeable outcomes.
The study therefore offers a diagnostic framework for assessing claims about planning-system learning after temporary urban interventions. Its main implication is methodological as well as theoretical: learning should be inferred from a documented pathway linking experience, feedback, change, transfer, and durable transformation in planning practice, rather than from the final physical outcome alone. Further longitudinal comparative research could extend this approach by following experimental interventions over longer periods and across different planning systems, allowing the conditions under which project-level experience becomes broader planning-system change to be examined more closely.
Keywords
Temporary Urban Interventions; Urban Experimentation; Continuity; Planning-System Learning; Process Tracing
References
Bruzzese, A. (2026). Reclaiming public space through governance transformation: The case of Piazze Aperte, Milan. Urban Planning, 11, Article 11032. https://doi.org/10.17645/up.11032 
Nogueira, F., Morais de Sá, A., & Moura, F. (2026). Urban experimentation as a pathway from temporary interventions to long term urban planning. Discover Cities, 3, Article 23. https://doi.org/10.1007/s44327-026-00202-6 
Schreiber, F. (2025). The long road from urban experimentation to the transformation of urban planning practice: The case of tactical urbanism in the city of Barcelona. Journal of Urban Mobility, 7, Article 100100. https://doi.org/10.1016/j.urbmob.2025.100100 
Stevens, Q., Leorke, D., Dovey, K., Awepuga, F., & Morley, M. (2024). From ‘pop-up’ to permanent: Temporary urbanism as an emerging mode of strategic open-space planning. Cities, 154, Article 105376. https://doi.org/10.1016/j.cities.2024.105376