Pop-up interventions to foster sustainable urban accessibility: top-down or bottom-up?

Sustainable urban accessibility has become a central concern for cities and decision-makers in the last few years. Cities across the globe have increasingly adopted pop-up urbanism principles, implementing pop-up interventions for space reallocation as a means to foster sustainable urban accessibility. However, current practices seem to overlook the needs of all users, especially those of vulnerable groups who face additional barriers to using public space and moving around cities. There is little research on how users are included in the design of pop-up interventions. To address this knowledge gap, this study identifies how mobility-related pop-up interventions can incorporate the needs of all users.
This research investigates two case studies, a top-down and a bottom-up project in Brussels, through a mixed methods approach. Ten experts involved in the implementation of the pop-up interventions were interviewed to identify how they considered the needs of users regarding four main elements: citizen involvement, physical accessibility, positive impact on the mobility of users, and perceived safety. These four elements were also investigated by surveying 43 users of the pop-up interventions and studying how they perceived the implemented solutions.
The research concludes that the needs of users, and especially those of vulnerable ones, were not specifically considered during the design process in the top-down intervention. The experts repeatedly cite time constraints as a reason for not involving the users in the design process. In the top-down case, the needs of vulnerable users were only considered after the implementation of the pop-up intervention, once this is turned into a permanent one. On the other hand, the bottom-up intervention was more in line with the needs of the local communities and took the needs of some vulnerable users better into account. In this regard, the cooperation with local organisations that work with the targeted groups was crucial, facilitating the design and implementation process while enabling the identification of the needs of citizens. Overall, a majority of participants stated that pop-up interventions would meet their needs if they were physically accessible and provided safety and comfort.
Experts who aim to take into account the needs of all users should find ways to include them at an earlier stage of the design process. The impact of the intervention on the mobility of users, as well as the perceptions of safety must be considered thoroughly since they may prevent people from using pop-up interventions. Paradoxically, designers and decision-makers are also highly concerned about the impacts of pop-up interventions on people that do not use the interventions directly, such as car drivers. Their needs receive more attention than the needs of vulnerable users. This might harm the progress towards increased sustainable urban accessibility.