Policy makers, urban planners, architects, sociologists, and economists are interested in creating urban areas that are both lively and safe. But are the safety and liveliness of neighborhoods independent characteristics? Or are they just two sides of the same coin? In a world where people avoid unsafe looking places, neighborhoods that look unsafe will be less lively, and will fail to harness the natural surveillance of human activity. But in a world where the preference for safe looking neighborhoods is small, the connection between the perception of safety and liveliness will be either weak or nonexistent. In this paper we explore the connection between the levels of activity and the perception of safety of neighborhoods in two major Italian cities by combining mobile phone data (as a proxy for activity or liveliness) with scores of perceived safety estimated using a Convolutional Neural Network trained on a dataset of Google Street View images scored using a crowdsourced visual perception survey. We find that: (i) safer looking neighborhoods are more active than what is expected from their population density, employee density, and distance to the city centre; and (ii) that the correlation between appearance of safety and activity is positive, strong, and significant, for females and people over 50, but negative for people under 30, suggesting that the behavioral impact of perception depends on the demographic of the population. Finally, we use occlusion techniques to identify the urban features that contribute to the appearance of safety, finding that greenery and street facing windows contribute to a positive appearance of safety (in agreement with Oscar Newman's defensible space theory). These results suggest that urban appearance modulates levels of human activity and, consequently, a neighborhood's rate of natural surveillance.
Evidence in favor of the broken windows theory has been presented by Kelling and Coles @cite_3 , who looked at data and stories from New York to Seattle to argue that community policing is an effective way to deter more serious forms of crime. Kelling and Sousa @cite_45 provide additional evidence by using an extensive dataset on crime, demographics, and economic data from New York City. More recently, Corman and Mocan @cite_6 used New York City data on the policing of misdemeanors (as a proxy for broken windows policing), and on robbery, car theft, and grand larceny, to provide evidence in support of broken windows policing.
@cite_45 @cite_6 @cite_3
2129784614 1599035031 2163587156 2271514814
Abstract This paper investigates the effect of economic conditions (carrots) and sanctions (sticks) on murder, assault, robbery, burglary, motor vehicle theft, grand larceny, and rape in New York City, using monthly time‐series data spanning 1974–99. Carrots are measured by the unemployment rate and the real minimum wage; sticks are measured by the number of felony arrests, size of the police force, and number of New York City residents in prison. In addition, the paper tests the validity of the “broken windows” hypothesis. Consistent with its implementation by the New York Police Department, we use misdemeanor arrests as a measure of broken‐windows policing. The broken‐windows hypothesis has validity in the case of robbery, motor vehicle theft, and grand larceny. While both economic and deterrence variables are important in explaining the decline in crime, the contribution of deterrence measures is larger than those of economic variables. Based on a groundbreaking theory of crime prevention, this practical and empowering book shows how citizens, business owners, and police can work together to ensure the safety of their communities. George Kelling, one of America s leading criminologists, has proven the success of his method across the country, from the New York City subways to the public parks of Seattle. Here, Kelling and urban anthropologist and lawyer Catherine Coles demonstrate that by controlling disorderly behavior in public spaces, we can create an environment where serious crime cannot flourish, and they explain how to adapt these effective methods for use in our own homes and communities." Imagine that the neighborhood you are living in is covered with graffiti, litter, and unreturned shopping carts. Would this reality cause you to litter more, trespass, or even steal? A thesis known as the broken windows theory suggests that signs of disorderly and petty criminal behavior trigger more disorderly and petty criminal behavior, thus causing the behavior to spread. This may cause neighborhoods to decay and the quality of life of its inhabitants to deteriorate. For a city government, this may be a vital policy issue. But does disorder really spread in neighborhoods? So far there has not been strong empirical support, and it is not clear what constitutes disorder and what may make it spread. We generated hypotheses about the spread of disorder and tested them in six field experiments. We found that, when people observe that others violated a certain social norm or legitimate rule, they are more likely to violate other norms or rules, which causes disorder to spread. Recent studies have examined racial disparities in stop-and-frisk, a widely employed but controversial policing tactic. The statistical evidence, however, has been limited and contradictory. We investigate by analyzing three million stops in New York City over five years, focusing on cases where officers suspected the stopped individual of criminal possession of a weapon (CPW). For each CPW stop, we estimate the ex ante probability that the detained suspect has a weapon. We find that in more than 40 of cases, the likelihood of finding a weapon (typically a knife) was less than 1 , raising concerns that the legal requirement of “reasonable suspicion” was often not met. We further find that blacks and Hispanics were disproportionately stopped in these low hit rate contexts, a phenomenon that we trace to two factors: (1) lower thresholds for stopping individuals — regardless of race — in high-crime, predominately minority areas, particularly public housing; and (2) lower thresholds for stopping minorities relative to similarly situated whites. Finally, we demonstrate that by conducting only the 6 of stops that are statistically most likely to result in weapons seizure, one can both recover the majority of weapons and mitigate racial disparities in who is stopped. We show that this statistically informed stopping strategy can be approximated by simple, easily implemented heuristics with little loss in efficiency.