Neighbors did some research trying to identify what impact trails have on crime but in general came up empty. There just did not appear to be any significant literature or studies that could provide evidence one way or the other. The question has remained unanswered all these months.
Oftentimes, how you frame the question is critical to whether it can be answered. We had been looking for information about trails and crime. Right thought but not quite the right formulation. It turns out that there is in fact a good deal of information about crime in neighborhoods but it is cast along different vectors. What we really want to know is whether having more non-residential traffic in the neighborhoods is likely to lead to an increase in crime (whether that increase arises from increased foot-traffic on the trails or vehicle traffic to trailheads).
When you ask that question, you discover that there is quite a bit of research. The research falls into three categories: 1) the effect of volume of vehicle traffic on neighborhood crime, 2) the effect of neighborhood permeability (access) on crime, and 3) the effect of mixed-use activities (commerce, trails or any other feature that increases use of a neighborhood by non-residents) on crime. In all three cases the evidence is clear that increased vehicle traffic is associated with increased crime, that increased permeability is associated with increased crime and that increased non-residential use (up to a certain density) increases residential neighborhood crime.
In light of this evidence, we have a much clearer answer to the question which SFC was unable to answer – Yes, increased connected trails through the neighborhood is likely to lead to an increase in crime in the neighborhood.
SFC was heavily criticized during the Visioning process public meetings for being unable to answer two other critical questions which were 1) Who will pay for and maintain the trails and bridges once they are completed and 2) Who will pay for and conduct security along the new trails. SFC had no plans to deal with either maintenance or security. Indeed, leading up to the public meetings, SFC denied that there were any existing Quality-of-Life issues or crime associated with the existing greenspaces; a position they maintained until Park Pride employees actually visited one of the existing parks and discovered the extent of the existing QOL/crime problems.
The upshot of this is that it is now clear that despite SFC’s hypothesis that increased trail traffic might control crime in the neighborhood, empirical data establishes that increased vehicular traffic, increased neighborhood permeability, and increased non-residential use are individually and together likely to lead to increased crime in the neighborhood and SFC has no plans in place to deal with that increased crime.
I think the discovery of this empirical information is important. It is now clear that there are very material costs to the SFC plan (aside from the financial costs of building the trails and bridges) and virtually no benefits. We now have the research and documentation that answers the questions which SFC was unwilling or unable to address. Connected trails will reduce conservation (wildlife and habitat). Connected trails will reduce property values. Connected trails will reduce Quality-of-Life. Connected trails will reduce neighborhood security and safety.
Sources of information regarding the links between vehicular traffic and crime, neighborhood permeability and crime, and non-residential use and crime are:
Neighborhood Permeability and Burglary Rates by Garland F. White
“Permeability is a significant influence on neighborhood burglary rates when neighborhood economic factors, instability, and structural density are controlled.”
Permeability, Access Opportunities and Crime by Stephen Brown (UK)
“Current national and local planning guidance places a significant emphasis on sustainable forms of transport with the aim of encouraging walking, cycling and public transport as alternatives to the private car. However, the Government also now recognizes that crime free communities are a crucial component of sustainability. Research and Crime Pattern Analysis shows a direct link between access opportunities and crime. In other words, the way and extent to which people can move around an area has a very significant influence on its likely level of crime.”
Defensible Space: Deterring Crime and Building Community from Department of Housing and Urban Development
“In Atlanta, Georgia, and Richmond, Virginia, neighborhoods that are harder to drive through (narrow streets, one way streets, few straight thoroughfares) have significantly less crime than those that are more permeable. In St. Louis, Missouri, private streets have much lower levels of criminal activity than adjacent blocks with similar housing types.”
Mixed-Use Neighborhoods Reduce Some Violent Crimes, Study Says by Christopher Browning. The headline is misleading as to the actual findings of the research. Key finding with emphasis added.
"The researchers found that the number of homicides and aggravated assaults increased in low-density mixed-use neighborhoods as the density increased, but then began to decline after a threshold of density was met. However, robbery levels continued to increase right along with commercial-residential density."
Traffic Calming and Crime Prevention by Kate Wright
“Although few studies of the relationship between traffic calming and crime prevention exist, there’s growing evidence that residents in neighborhoods with slower streets are more likely to take ownership of those streets and in so doing increase the surveillance that is key to deterring crime.”
The People Paradox by Nicole Stelle Garnett
“All of these studies cast serious doubt on Jacobs’s (and the new urbanists’) core claims about the benefits of mixed-land-use neighborhoods. Commercial land uses [i.e. increased non-residential use] appear to generate, rather than suppress, crime and disorder. And, at least insofar as neighborhood-level social capital is reflected in resident surveys about neighborhood social cohesion and trust, they also appear to suppress, rather than generate, social capital.”
