Urban experimentation as a pathway from temporary interventions to long term urban planning

Street experimentation has gained prominence as cities experiment with flexible, low-cost solutions to address evolving spatial and mobility needs rapidly. This paper investigates the factors that differentiate temporary from indefinite street-level interventions using a typological framework derived from interventions performed during the COVID-19 pandemic. Drawing on the Shifting Streets database, which documents street-level interventions implemented during the COVID-19 pandemic, we identify recurring types of street interventions based on their spatial, functional, and regulatory characteristics. The database documents 1,313 policy actions across 524 jurisdictions worldwide; the analysis presented here focuses on a subset of street-level interventions implemented by public authorities that met the analytical criteria adopted in this study. These intervention types are then used to examine whether policies were implemented as explicitly temporary or with no defined end date. In the dataset, anticipated longevity refers to how interventions were officially described by public authorities at the time of implementation, either as temporary or as having no specified end date, reflecting policy intent rather than observed duration. The model revealed that interventions involving substantial reallocations of street space to pedestrians and cyclists, commercial sidewalk activation, and physically intensive transformations were more likely to be temporary. In contrast, lighter, active mobility-first interventions and those involving minimal regulation were more often implemented with indefinite timelines. The model performed with an accuracy of roughly 70%, suggesting that design and functional features carry predictive power for policy longevity. Notably, none of the extracted components captured public participation or community co-creation, raising questions about the equity of these increasingly common interventions. The results support the interpretation of street experimentation as policy experiments, rapidly deployed and easily reversed. These interventions can act as triggers for broader urban transformations. However, when focused on commercial activation and outdoor dining, they may contribute to processes associated with gentrification. Moreover, their agility may come at the cost of procedural justice and long-term inclusion. The study concludes that although street experimentation promotes innovation and flexibility, its formal adoption requires strong safeguards to ensure public accountability, especially when temporary interventions evolve into permanent ones.