Anometer is very simple.
Swipe left at the start of a zone. This switches the large number to display the average speed since the start of the zone. If you swipe left again the averaging function is reset. Typically you would do this as you pass each camera, because it is the average speed between camera pairs that is monitored for violations. In this mode, the instantaneous speed is shown as a smaller number at the bottom right of the screen.
Swipe right at the end of a zone. This resets the large number to display instantaneous speed.
Zone start and end locations are remembered and shared with other app users via iCloud. There is no personally identifying data associated with these locations.
It is the responsibility of the driver of a vehicle to adhere to all relevant local laws including those relating to speed and use of devices at all times.