This is a good point, but as I stated previously, current crime hotspots do indeed have predictive value of where future crimes will occur. Moreover, I am not forcing the user to take a specific route, they have a plethora of options to choose based on their preferences for both speed and safety. If you don't believe me you don't have to download the app.

Also your whole comparison of Baltimore to NYC is completely dumbfounded because the user will be choosing between routes that go through the same city, with all route options having being taken a similar number of times. Hence if one route has a significantly greater number of crime hotspots that will almost certainly correlate with the crime:trips attempted ratio. Also as I said previously, the user can choose between multiple options and I am not forcing him to take any specific route.

Edit: brightbehaviorist I totally understand what you're saying that the crime:trips ratio would be a better indicator of the safety than just crimes, and I am working on integrating this into the algo. However, I think it is still very useful to see local crime hotspots along the route you're taking, and I has said before, the user can choose between a plethora of options based on their preferences (like google maps). Thanks for your feedback!