Anne - There have been posts on how how what we see (effect of light) and hear (soothing soundscapes. Ivy inspired me from her comment below yours to look into maybe how smell could have alter behaviors in spaces as well so I posted my research about the calming effects of orange scent in Dutch jail here:
http://openideo.com/challenge/womens-safety/research/common-scents-aromas-that-calm-soothe
Let's attack this problem from all five senses!

Ivy - There's quite a bit of research actually from some quick searches I found. You're right there is a lot of research on scents affecting shopping habits (orange is the way to go)
http://www.psmag.com/navigation/business-economics/how-scent-marketing-changes-shopping-behavior-50247/
Here's an even more relevant article about scent's where a jail in the Netherlands pumped orange aromas throughout the ventilation systems for a four week study and reduced aggression and fighting in the cells.
http://openideo.com/challenge/womens-safety/research/common-scents-aromas-that-calm-soothe
All our senses really affect safety, how can we use all five to the advantage of urban safety? Excited to see what ideas come up in the next phase!

Jason - Thanks so much for this interview about neighborhood watch programs. I found this presentation that reviewed the effectiveness of neighborhood watch programs across the U.S. that you may find interesting.
http://www.cops.usdoj.gov/Publications/e040825133-res-review3.pdf
A key thing I missed when thinking about neighborhood watch programs was how they need to regularly communicate with existing law enforcement to really nurture community safety. Audree F. wrote a great write-up about improving relations with local police below:
http://openideo.com/challenge/womens-safety/research/improving-relations-between-the-police-and-local-communities
Excited to see how we can pull these insights into the Idea phase. Thanks again Jason for the interview.