How Urban Planners Can Encourage ‘Vibrancy’ — and Create Safer Cities


Wharton's Shane Jensen discusses his research on promoting vibrancy in cities.
There is plenty of debate about what makes one neighborhood safe, while others experience high incidences of crime. Recent Wharton research looks at the role that urban planners have to play, analyzing high resolution data about cities, such as population density or zoning, to help evaluate how efficient their built environment is in promoting “vibrancy,” and to potentially guide future urban development.
“I’m obsessed with this idea of vibrancy,” says Wharton statistics professor Shane T. Jensen, explaining that contemporary urban hypotheses suggest that positive, healthy activity or energy in a neighborhood helps discourage crime. Jensen is co-author of the paper, which uses Philadelphia as a case example. Among his research specialties is urban analytics, where he gleans insights from publicly available data regarding zoning, construction activity, Census demographics and mapping technologies.
According to Jensen, one his co-authors — architect Rachel Thurston from Stantec — found that much of urban development tends not to be based on empirical findings, but more on anecdotal assumptions. Jensen hopes that research and evaluation of those practices could lead to better urban planning, more vibrancy in neighborhoods and hopefully reduced crime. He discussed the chief insights of the research, which was also co-authored by Wharton statistics professor Dylan Small and Wharton doctoral student Colman Humphrey, on the Dollars and Change show on Wharton Business Radio on SiriusXM channel 111. (Listen to the podcast at the top of this page.)
Below are key highlights from the discussion:
Could vibrancy help reduce urban crime? In any urban setting, “certain neighborhoods or street corners are very vibrant, and there is a lot of human activity at all hours of the day,” says Jensen. How best to quantify such vibrancy in a particular neighborhood or street is one of the primary objectives of his research. “After quantifying it, can we evaluate whether or not it helps reduce crime? Those are the overarching goals of my research.”
Jensen’s hope is to be able to appraise current procedures for how neighborhoods are zoned or laid out and use the learning from that “in an intervention sense.” For example, the researchers might discover that mixing commercial and residential development is critical to promoting vibrancy, and planners could then zone accordingly.
In their studies of small neighborhood units in Philadelphia, the researchers compared business vibrancy and the location of businesses with crime data to see which locations are high-crime or low-crime. They found that in particular neighborhoods, more crimes occur near businesses, like theft and burglary. But they also found that businesses that are open for longer hours, like cafes, tend to have less crime than others. “That’s an intervenable thing,” says Jensen, who wants to be able to bring to the development planning process more data and hypothesis testing with his research.
A focus on local, organic development:According to Jensen, the old model of urban planning supported large scale renewal projects in the 1950s and 1960s where cities were built “around the automobile.” As an example, he pointed to public works projects like the Benjamin Franklin Parkway in Philadelphia. “The pushback against those types of projects came from people like [urban renewal activist] Jane Jacobs in the 1960s, who said that the way to develop a city is to focus on the small-scale, develop neighborhoods organically, and focus on the mixing of commercial and residential,” says Jensen. “The idea is to have local initiatives and small-scale [activities] that are intended to encourage people on the street, milling about at all hours of the day and [generating] a lot of pedestrian traffic.”
“The idea is to have local initiatives and small-scale [activities] that are intended to encourage people on the street, milling about at all hours of the day and [generating] a lot of pedestrian traffic.”
Jensen pointed to the work done by Janette Sadik-Khan, former commissioner of the New York City Department of Transportation, who is best known for creating bike lanes and pedestrian plazas in the city. He said in formerly blighted neighborhoods like Times Square, the effort was to close off streets and “encourage more hanging out.”
Counter-intuitive findings: Jensen’s research found that Philadelphia neighborhoods with a lot of vacant land tended to have high crime rates. He says the finding was not surprising, since “we’ve always associated a lot of vacancy with poor health of the neighborhood.” However, when the researchers looked more closely at where exactly the crimes occur, it turned out that people don’t actually go to vacant lots to commit crimes. “At the aggregate level, vacancy is a sign of poor neighborhood health, but if you want to predict where crimes are occurring within unhealthy neighborhoods, they tend not to be occurring near those vacant lots,” he said.
Jensen pointed to other studies at Penn including one that conducted a controlled experiment on greening some vacant lots with parks or other such “nice spaces,” while leaving others vacant. That study found that the crime rates didn’t differ dramatically between those areas that were greened and those that were left vacant. However, there was a huge difference in the perceptions of crime between residents of areas where vacant lots were greened, and those in other neighborhoods that didn’t see such improvements.
Jensen saw a cohesive narrative emerging when the findings of those Penn studies and those of his recent research are combined.
“Grand, urban renewal projects like slamming an entire highway through a city center displace a ton of people and obviously change the entire fabric of neighborhoods.”
Making sounder development decisions: Jensen noted that there is value in providing the urban planning community with empirical findings upon which to base development decisions. “People weren’t doing a lot of experimentation or testing or even evaluation quantitatively about where crime was occurring, [whether the] zoning was mixed or not mixed, and the consequences of putting in these cookie cutter-type developments versus something more organic in the neighborhood,” Jensen said. “They seemed to say, ‘The giant building with the Applebee’s on the street corner; that’s worked for us in the past. We will just keep doing that until it stops working.’” He added that continued “studies of cities at a high-resolution level will help to illustrate that cities really do change, evolve and function at a very local level.”
The findings from such studies will also prevent huge errors, noted Jensen. “Grand, urban renewal projects like slamming an entire highway through a city center displace a ton of people and obviously change the entire fabric of neighborhoods. We should be very cautious about doing something like that, because so much of city life and vibrancy happens at a very local level.”
Jensen encouraged city planners to take a simple approach: Evaluate their options based on those aspects in a neighborhood they really like and find to be vibrant, even if that vibrancy may be defined in various ways. Integrating business data into information on the number of vacant lots and those that have been greened in a particular neighborhood could lead to even more insights, he said. If vacant lots were greened in areas where some businesses already existed, that could have a better effect either on the perception of crime, or the real crime rate, he added.

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