Speaker
Description
The urgency of the climate crisis demands a transformation of urban mobility, and reallocating street space from traffic to people plays a key role in this. Yet such reallocations are often met with political resistance, financial constraints, and regulatory obstacles. In response, there has been a turn towards experimental approaches: In the last decade, street experiments such as tactical urbanism interventions or pop-up measures have spread globally (Bertolini, 2020). What began as bottom-up tactical urbanism (Lydon et al., 2015) has been increasingly adopted by city governments, accelerated by the COVID-19 pandemic (Zhao et al., 2024), spread from pioneering global cities to a wide range of smaller municipalities, and evolved from individual projects to city-wide programmes (such as the Piazze Aperte in Milano, see Bruzzese, 2026).
At the heart of this turn is the expectation that short-term interventions can serve as levers for long-term, fundamental change. But the evidence is ambivalent: While many studies highlight beneficial impacts (for an overview see Bertolini, 2020) and elaborate conceptually on the transformative capacity of street experiments (Kinigadner et al., 2024; VanHoose et al., 2022), others point to conflicts, failures, and rollbacks (De Boeck et al., 2026; Günay, 2024; Villani & Talamini, 2023). Thus, there is a need to clarify how, to what extent, and under what conditions street experiments can contribute to transformation.
In a systematic review of the literature, I identified four underlying theories of change through which street experiments are expected to foster transformation: paving the way for permanent implementation, building niches that scale up to challenge the mobility regime, shifting attitudes and everyday practices, or opening arenas of conflict from which radical alternatives can emerge (Grandel & Berger, 2025). While there are many empirical articles contributing fruitful case studies that shed light on central assumptions of those pathways, the literature at this stage still offers only scattered insights into specific contexts. A more systematic understanding requires further research, especially outside well-studied forerunner cities such as Barcelona.
Therefore, there has been the call in the community for more cross-city and cross-country comparisons to better understand how “institutional frameworks and planning cultures shape the policy agendas, governance modes, co-production approaches, and political dynamics and tensions of place-specific experimentation” (Smeds et al., 2025). Another under-researched aspect in this regard are the political contexts and planning situations, from which street experiments emerge: While in-depth case studies demonstrate their importance (such as Vitale Brovarone et al., 2023), their influence on objectives, implementation, and long-term impact of street experiments have not yet been systematically analysed.
In our contribution, we would like to address these gaps by investigating what role street experiments play within wider public space redesign processes, and how their contribution differs across spatial, political, and institutional contexts. As case studies, we analyse seven pilot projects from an Austrian R&I flagship project on the transformation of traffic spaces, from which in five street experiments have been conducted. The case studies are located in very different municipalities, ranging from the capital, Vienna, to small rural towns. The research questions are:
RQ1: What are the contexts, key actors, and rationales for (not) conducting street experiments in the context of the public space redesign pilots?
RQ2: What kind of street experiments are implemented and how?
RQ3: What influence do the street experiments have on the planning processes and institutional contexts in which they are embedded?
Conceptual framework
Conceptually, our analysis builds on the scholarship on street experiments and their relation to urban transformation. Rather than treating street experiments as isolated interventions, we view them as embedded in longer planning trajectories—as "parts of longer and uneven trajectories, where cracks have been openings through which alternative futures may begin to take shape" (Mukhtar-Landgren et al., 2026, 3). This perspective shifts attention from asking whether street experiments "work" in general to understanding how they are shaped by and interact with specific institutional, political, and spatial conditions.
To capture the influence of street experiments on the traffic space redesign projects and the institutional settings in which they were embedded, we developed an analytical framework distinguishing three dimensions of influence: effects on planning processes (e.g., political and administrative decision-making), planning products (e.g., tactical implementation, permanent implementation, further plans, strategies, policy documents), and institutional contexts (e.g., knowledge, skills, routines, conventions, instruments).
To interpret our empirical findings, we use the four pathways identified by Grandel & Berger (2025) as an analytical lens.
Material and methods
The study draws on a comparative case analysis of seven pilot projects from a four-year Austrian research and innovation flagship project on the redesign of traffic spaces. The programme brought together municipalities, planning consultancies, research institutions, and public-sector intermediaries. Over the course of the programme, street experiments were conducted in five of the seven pilots. The cases represent a maximum variation selection within the same overarching governance system: they range from Austria's capital Vienna to small rural towns, capturing very different municipal resources, political dynamics, regional cultures, and types of redesign projects.
Our empirical material comes from an extensive process evaluation conducted throughout the programme. Data sources include: continuous activity logbooks maintained by pilot teams; regular structured reflections on lessons learned; concluding collections of key moments, learning outcomes, drivers, and barriers; and in-depth group discussions, focus groups, and semi-structured expert interviews with politicians, public servants, planning consultants, and local stakeholders and citizens. Accompanying the pilots over four years gave us strong contextual knowledge and built trust, enabling open, multi-perspective accounts of both successes and difficulties.
Analysis proceeded in two stages. First, we examined all seven pilots to understand why street experiments were carried out in some cases but not others, focusing on context, key actors, and rationales. Second, we conducted detailed actor and process analyses of the five pilots that implemented street experiments, comparing cases within similar groups (large cities, middle-sized, small towns with similar pilot challenges in each group) and across groups.
Expected results
Preliminary analysis reveals a strong contrast in how and why street experiments are used across different municipal contexts. In the large cities—Vienna and Graz—street experiments were integrated into existing or emerging tactical urbanism programmes. Here, experimentation served primarily as a communication and participation tool to prepare the ground for already-envisaged permanent redesigns, and as a learning step for rolling out city-wide programmes. Regarding influence, in Vienna the temporary character lowered the political threshold for the first Superblock implementation and allowed practical questions to be resolved internally before permanent construction. The experiment confirmed the strategic direction, strengthening ambition and catalysed a discursive shift: Tactical Urbanism entered strategic documents, the mayor publicly committed, and other districts demanded similar projects. However, administrative routines remained unchanged and the transfer to permanent solutions left maintenance questions open. In Graz, the provisional pedestrian zone enabled iterative fine-tuning of furniture and loading zones, generating practical learnings for the final design without redirecting the overall vision.
In the small towns—Deutschkreutz, Langenlois, and St. Gallenkirch—the logic was fundamentally different. Street experiments emerged as a response to blocked or sluggish planning processes: after conventional planning approaches had hit institutional or political dead ends, project actors pushed for temporary interventions as a way to create momentum, demonstrate possibilities, and keep the process alive. Rather than a strategic tool in a predefined programme, experimentation here functioned as a pragmatic, often improvised workaround—a "plan B" when other doors had closed.
In the two pilots where no street experiment was conducted (St. Pölten and Salzburg), the reasons were similar: one was at too early a planning stage for temporary interventions to be meaningful, while in the other the political conditions were not yet ripe.
These findings suggest that street experiments are not a universal blueprint that can be scaled and transferred arbitrarily. Instead, they take fundamentally different forms depending on the context: as a planned, programmatic instrument in resource-rich cities with established experimentation cultures, or as a reactive, opportunity-driven tactic in smaller municipalities where the capacity for strategic experimentation is limited. This difference in rationale has direct implications for the type of experiment implemented (scope, duration, participatory design), the actors driving it, and the kind of impact it can realistically achieve.
Relevance and implications
This study contributes to the ongoing debate on whether experimentation can catalyse deeper transformations or remains limited to incremental, piecemeal action. Our preliminary findings suggest that the answer depends both on the experiment itself and on the context in which it is embedded. In the large cities with strong institutional capacity, street experiments are part of a managed transition—they accelerate and legitimize pathways that are already being pursued. In the small towns, they might break open deadlocked situations and create new possibilities, yet their institutional footprint remained fragile.
This has implications for both research and practice. For planning scholarship, our findings underscore the need to move beyond decontextualized assessments of whether street experiments "work" and toward a more nuanced understanding of how they interact with different institutional and political settings. For practitioners and policymakers, the message is that street experiments should be designed and evaluated with a clear understanding of their strategic purpose within the specific planning context—as a means, not an end in themselves. When planning conceptually for street experiments, it is crucial to think through how they are expected to produce longer-term institutional effects, and to build in evaluation mechanisms that can track and adjust these effects over time.
The contribution will conclude by reflecting on which of the four transformation pathways are activated in different contexts, and what this means for the potential of street experiments to contribute to a genuine transformation of urban mobility—not just a managed incremental shift within the existing regime.
References
Bertolini, L. (2020). From “streets for traffic” to “streets for people”: can street experiments transform urban mobility? Transport Reviews, 40(6), 734–753. https://doi.org/10.1080/01441647.2020.1761907
Bruzzese, A. (2026). Reclaiming Public Space Through Governance Transformation: The Case of Piazze Aperte, Milan. Urban Planning, 11, 11032. https://doi.org/10.17645/up.11032
De Boeck, S., Honey-Rosés, J., Van Acker, M., & Vanoutrive, T. (2026). Barcelona’s Superblocks: An unfinished urban planning policy paradigm shift. Cities, 171, 106710. https://doi.org/10.1016/j.cities.2025.106710
Grandel, G., & Berger, M. (2025). Pathways from street experiments to transformation: a systematic review of theories of change. Transport Reviews, 45(6), 924–947. https://doi.org/10.1080/01441647.2025.2523282
Günay, M. (2024). ‘Doing’ conflict in traffic experiments. In M. Grubbauer, A. Manganelli, & L. Volont, Conflicts in Urban Future-Making. Governance, Institutions, and Transformative Change. TRANSCRIPT VERLAG.
Kinigadner, J., Büttner, B., Rivas De Gante, A., & Aumann, S. (2024). How to transform urban spaces and mobility: a framework for analysing street experiments. Journal of Urban Design, 1–21. https://doi.org/10.1080/13574809.2024.2320918
Lydon, M., Garcia, A., & Duany, A. (2015). Tactical urbanism: short-term action for long-term change. Island Press.
Mukhtar-Landgren, D., Von Wirth, T., Bertolini, L., & Torrens, J. (2026). Urban living labs as cracks, not doors: Reimagining experimentation in transport (and beyond). Journal of Transport Geography, 132, 104598. https://doi.org/10.1016/j.jtrangeo.2026.104598
Smeds, E., Mukhtar-Landgren, D., & Oldbury, K. (2025). Urban Experimentation. Varieties of urban experimentation: institutional drivers and planning cultures [World Planning Schools Congress, Special Session 28].
VanHoose, K., de Gante, A. R., Bertolini, L., Kinigadner, J., & Büttner, B. (2022). From temporary arrangements to permanent change: Assessing the transitional capacity of city street experiments. Journal of Urban Mobility, 2, 100015. https://doi.org/10.1016/j.urbmob.2022.100015
Villani, C., & Talamini, G. (2023). Failed pedestrian street experiments in high-density urban Asia: A matter of policies? Journal of Urban Mobility, 4, 100069. https://doi.org/10.1016/j.urbmob.2023.100069
Vitale Brovarone, E., Staricco, L., & Verlinghieri, E. (2023). Whose is this street? Actors and conflicts in the governance of pedestrianisation processes. Journal of Transport Geography, 107, 103528. https://doi.org/10.1016/j.jtrangeo.2022.103528
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