The role of the Digital Participatory Platforms in street experiment processes. Two cases from Italy

• Digital Participatory Platforms (DPPs) play a relevant role in simplifying and expanding citizens' engagement. • The impacts of existing DPPs highlight advantages, drawbacks and limitations. • Five key readings for comparison of DPPs are provided and mobilised. • The effectiveness of the applications of DDPs in tactical experiments is investigated in two test beds. • Several key aspects of the use and utility of DPPs in policy processes are provided. Digital Participatory Platforms (DPPs) play a significant role in expanding citizens' opportunities to engage in public debate through their technical agency and crowdsourcing approach. They enable the collection and sharing of opinions, ideas, direct experiences, and data without the spatial, temporal, financial, and practical limitations of traditional, non-digital participatory processes. In the mobility domain, DPPs have been used to improve knowledge of mobility habits and needs, assess the quality of mobility services, and facilitate interaction among stakeholders involved in planning, managing, and implementing mobility solutions. Despite these advantages, DPPs also present various drawbacks and limitations. These stem both from the inherent challenges of managing any public participation process and from the digital nature of such platforms, which require disruptive changes compared to traditional engagement techniques. This paper examines the processes in which DPPs are embedded, as well as the type, structure, design, and functionality of two platforms (Commonplace and Decidim) tested in Bologna and Milan (Italy). It applies five analytical lenses -objectives, management, participation, technology, and effects - to advance understanding of the role of DPPs in supporting the co-creation and evaluation of tactical urbanism experiments. Key lessons highlight the importance of aligning participation goals with the administrative and resource capacity to manage platforms effectively; ensuring continuous management, promotion, and integration with existing local engagement methods; and adopting complementary offline approaches to guarantee inclusivity.