When real-time data lies, prefer stability over freshness

Building Transport Tracker, the hardest problem was not ingesting feeds — it was deciding which source to believe when they disagreed, and how to present a number that moves the way a human expects.

A slightly stale but stable number beats a precise one that jitters.

The reconciliation layer keeps a confidence-weighted estimate per vehicle and damps the prediction so it never jumps erratically. Users never see the underlying disagreement; they see one steady countdown that they can plan around.