Among the most significant impacts related to the spread of settlements and the densification of urban areas, the reduction in the availability of public green spaces plays a central role in the definition of livable cities, in terms of the environment and social cohesion, interaction, and equality. In the framework of target 11.7 of the Sustainable Development Goals (SDG) 11, the United Nations has established the objective of ensuring universal, safe, and inclusive access to public spaces by 2030, for women, children, the elderly, and people with disabilities. This study proposes the evaluation of this objective for the urban area of the 14 Italian metropolitan cities, as defined by EUROSTAT and adopted by the United Nations and the Nature Restoration Law (NRL). A methodology based on open-source data and network analysis tools is tested for the provision of an unprecedented mapping of the availability and accessibility to green urban public spaces, which shows that less than 30% of metropolitan city residents have access to a green space within 300 m on foot, according to OpenStreetMap data (less than one in five for the Urban Atlas data). Furthermore, a critical analysis on the geometric and semantic definition of green urban public spaces adopted by the main European and international tools is carried out, which underlines the strategic role of crowdsourcing but also the need for mapping rules that make the data more consistent with the monitoring objectives set at the institutional level.

The 3-30-300 rule, proposed by Cecil Konijnendijk, is oriented towards the design of greener cities. However, subsequent literature has revealed some application limits due to overly simple definitions (visibility of 3 trees), fixed thresholds (30% tree cover) and theoretical distances (300 m to the park) that do not consider ecological quality, real green area proximity and possible socio-demographic differences. The present research attempts to overcome these limitations through the elaboration of a scalable composite index that, starting from the original rule, integrates ecological, infrastructural and population variables to give a more robust measure of the availability and usability of urban green. The index was tested in the study area of the urban centre of Ferrara (Italy). Three sub-indices were calculated for each building: Indicator 3—Visibility (I3), Indicator 30—Tree cover (I30), and Indicator 300—Green area proximity (I300). Once normalized and weighted, the three indicators were aggregated into a composite index conceived as a scalable and replicable framework adaptable to diverse urban settings. By spatially integrating population data, the methodology explicitly embeds the distributional dimension of climate justice, supporting evidence-based adaptation strategies and equitable urban regeneration policies. Moving beyond the binary logic of the original 3-30-300 rule, the approach provides an operational decision-support tool to detect intra-urban inequalities, to address just green transitions and to monitor urban greening interventions over time.

Mobility plays a fundamental role in modern cities. How citizens experience the urban environment, access city core services, and participate in city life, strongly depends on its mobility organization and efficiency. The challenges that municipalities face are very ambitious: on the one hand, administrators must guarantee their citizens the right to mobility and to easily access local services; on the other hand, they need to minimize the economic, social, and environmental costs of the mobility system. Municipalities are increasingly facing problems of traffic congestion, road safety, energy dependency and air pollution, and therefore encouraging a shift towards sustainable mobility habits based on active mobility is of central importance. Active modes, such as cycling, should be particularly encouraged, especially for local recurrent journeys (e.g., home--to--school, home--to--work). In this context, addressing and mitigating commuter-generated traffic requires engaging public and private stakeholders through innovative and collaborative approaches that focus not only on supply (e.g., roads and vehicles) but also on transportation demand management. In this paper, we present an end-to-end solution, called Play&Go Corporate, for enabling urban cyclability and its concrete exploitation in the realization of a home-to-work sustainable mobility campaign (i.e., Bike2Work) targeting employees of public and private companies. To evaluate the effectiveness of the proposed solution we developed two analyses: the first to carefully analyze the user experience and any behaviour change related to the Bike2Work mobility campaign, and the second to demonstrate how exploiting the collected data we can potentially inform and guide the involved municipality (i.e., Ferrara, a city in Northern Italy) in improving urban cyclability.