High Crime Areas (youtube.com)
This is 4 years old, but some cities will make public stats for crimes and the point on a map where they happened. Shootings is the gold standard. Murders is not enough information, since that is a smaller number (maybe 1/100th of the number of shootings).
People can avoid moving their families to those places. People who live there can take special training for handling violence and handling violent people.
Violence can also occur in a corridor or be focused in two points, and there is a line between these two centers, which you can know that's an area you might be walking through. If you're using GoogleMaps or an Uber, the fastest route might go through a high crime area. Do you want to take a safer route? On the other hand, an interstate highway might go right through a dangerous area, but since it's an interstate, you're not going to have a lot of violence on that road (unless there are active protests).