A medical doctor wrote about violence upon innocent black men, sometimes standing at a bus stop in a book called Wrong Place, Wrong Time by John A. Rich, an MD with an MPH. Click here: http://www.amazon.com/Wrong-Place-Time-Trauma-Violence/dp/1421403986/ref=sr_1_2?s=books&ie=UTF8&qid=1406426730&sr=1-2&keywords=Wrong+place%2C+wrong+time
Another study has recently been published with intervention for clients of violence has been found supportive. Intervention (click) has recently been studied. PTSD is helped with the client support.
Meanwhile, to prevent a good bit of violence we can use the Buddy System as often as possible. We can also consider putting a pink "Buddy System" sticker on our bumper or wherever will reach the most people.