Location Always On???

The app was correct the only time Ive used it so I cant really comment on that, but.....,
Why does the app need to know my location in the background? I only want to know about the train when Im taking the train which is when I open the app. I dont need alerts otherwise. There should be a "while in use" option for the location services. Draining my battery for no reason

illini678934567 about ProximiT: MBTA Boston Transit