“No tracking. No cookies. Your vibration data is your own damn business!”
Transit counts subway stops from your phone’s motion sensors. A moving train shakes at about 5 Hz and a walking rider at about 2 Hz, and a model trained on a week of NYC rides gets the position right 90% of the time. Both models run on the phone and send nothing to Transit’s servers. A small transit app just showed every ad-funded giant that location features work fine without hoarding location data.