While we're on the subject, if you're walking around the neighborhood, keep in mind the fact that some streets are inherently safer than others. When you have a choice, use those with more slower-moving traffic for instance, Spruce rather than Walnut or Chestnut; those with open commercial establishments, people coming and going, and a minimum of places where people can lurk unseen; and house fronts close to the sidewalk rather than set back. Many street corners also have Penn Police call boxes easily spotted because of blue lights above them; in your travels, it won't hurt to take note of where they are and plan your routes accordingly because they can be more effective than 911 calls on your cell phone.
Crime does not run rampant in University City. But there are, indeed, people who occasionally come around with evil on their minds and in their hearts. Miscreants like these generally don't have particular subjects in mind but seek targets of opportunity.