Superblock interventions: the need for policy design and realist evaluations to unpack complexity

Superblock interventions offer considerable potential for transforming urban environments in line with broader agendas for sustainability, climate adaptation, and social equity. They aim to reclaim public space, reduce car dependency, and promote more liveable, inclusive environments. Despite growing interest in these urban interventions worldwide, efforts to evaluate them have remained limited. Recently, more quantitative impact-focused assessments of Barcelona´s Superblocks have been advocated for. However, we argue there is also a pressing need to adopt more comprehensive, theory-informed approaches – such as policy design and realist evaluations – to unpack complexity associated with Superblock interventions, not only in Barcelona but also in other cities worldwide. These evaluations can help assess whether an intervention has been appropriately designed, and understand how and why they work (or not) in a particular urban setting, by identifying the underlying causal mechanisms, key contextual conditions, and implementation dynamics that shape and generated certain outcomes. Such in-depth knowledge is essential to support iterative learning, and self-assessment processes of Superblocks by municipalities as well as provide clearer guidance for future design and implementation in other contexts. Ultimately, expanding evaluation practices of Superblock interventions in various cities will be critical for their successful scaling, contextualisation, and political legitimacy.