The app notes places where you notice. They are usually traffic jam, roadworks , speed limit, breathalyser, fog, speeding fine or police may stay here to fine the offenser. You can note what ever you want. If you move toward this noticed place on the radius = 500 meters, your phone will vibrate to prompt you to be more carefull. Some function such as find route , calculate distance from this place to your current place ... Don't hesitate to contact to my email firstname.lastname@example.org if there are some thing to ask . Thanks.