Urban Design, Space Syntax and Crime. An evidence-based approach to evaluate urban crime geographical displacement and surveillance efficiency

Spatial configuration analysis plays an important role in understanding the materials and intangible factors within built environments. Space Syntax is an important instrument in that aspect, as the decomposition of space in Isovists, Road-Centre Lines, or Visibility Graphs emulate tendencies of human natural movement in urban contexts. From the early ‘90s, Space Syntax methods have been applied to crime science, to unveil connections between urban design, citizen behaviour, and where crime occurrences happen; in fact, the urban space features are assumed in the literature as key factors to crime prevention. Several studies investigated relations between crime distribution and street-networks' spatial configuration identifying important correlations between movement, natural surveillance, and crime occurrences. Hence, the possibility to investigate the relationship between the crime distribution and the visual fields (VGA) in the urban scenario from the perspective of natural control emerges and represents an intriguing aspect, yet to be explored and integrated with other analyses. With this in consideration, this paper contributes to these discussions, as it evaluates the geographic distribution of crime occurrences regarding drug dealing and car break-ins offences in the historic centre of Pisa (Italy) and their possible correlation with street networks’ configurational properties. Starting from the Isovist concept, the spatial features of visual control and controllability measures (VGA) are investigated, as they represent useful tools to interpret the rational offender logic in deciding the suitable locations and opportunities to commit a crime and, as a consequence, to indicate a direction to lead crime prevention interventions. Further in-depth studies are finally proposed.