In order for the application to function properly, you must accept access to the device's location, so that the application can calculate when to alert you. You must also have internet access for the app to load the coordinates for the alerts. Warnings will be displayed if the application is open, it is recommended that while driving your phone is on a holder and the volume is turned up, so that you also receive sound warnings. If it is safe, you can contribute to the application yourself, by adding warnings, which you were not warned about, because no one reported the need for a warning before you. Also, if it is safe, you can answer after each warning whether the warning is still current or not, so that there are no redundant warnings, in places where there is no longer a need for it.