METROPOLITAN URBAN SAFETY. A RISK BASED METHODOLOGY TO SUPPORT METROPOLITAN PLANNING TOOLS

The growing security demand that citizens ask for, made clear by the daily news before the statistical data, imposes a reflection on how this emergency must be faced. What makes the city unsafe is not only the actual risk of being predatory crimes victims but also the perception of insecurity that is felt in certain spaces, closely related to urban decay and social unease, that manifests itself in various forms. Indeed, the security demand is related to a wide range of conditions that influence and alter the perception of urban spaces, making them look like insecure. In this sense, determinants are the physical elements of the urban environment, related to the way cities and spaces are planned, designed, constructed and managed. The goal of making a safer city is not only achievable through actions of control (police, video surveillance) or repressive. An integrated approach to safety is required, which sees socio-economic actions on the built environment work together the physical, functional and managerial ones. In this sense, the urban planning, through the environmental approach to safety, plays a fundamental role. The research addresses the issue through a methodology in which the traditional environmental approach to safety is treated as a territorial risk. The risk related to the occurrence of a criminal event is a function of three factors: hazard (H), namely the probability of criminal event occurrence; vulnerability (V), understood as the tendency of spaces to favour or discourage illicit behaviour and situations that generate insecurity; exposure (E), represented by people and goods. The methodology has been applied to the city of Milan. The application has highlighted some critical issues in the construction of maps related to the availability of data on the hazard factor and the fragmentation of information on the urban environment. A calibration of the model was necessary to make it more responsive to the needs of the case in question. In the application, a multiscale approach was adopted which, starting from the territorial scale, subsequently shifted the attention to a more limited portion of urban space, selected among those that showed the highest levels of vulnerability. In this context, a detailed analysis was carried out that allowed the comparison between scenarios. The application showed the reliability of the proposed model and allowed to detect how the actions for safety are not perfectly in synergy with the canonical aims of urban planning, laying the foundations for a review of the latter in terms of urban safety.