Editing Openai/691a5ca1-2b1c-8010-8cbd-8797f95aa8d9 (section)

==== 3. Live Activity as the “session HUD” ====

Yep, a Live Activity is a really natural fit here:

What it can show:
* Elapsed driving time (e.g. 3h 12m)
* Time remaining until the 4-h break (e.g. 48m to mandatory break)
* Maybe: - Distance so far - Current speed (rounded / smoothed) - Simple state: “Driving / On break”

Why it’s useful:
* Shows up on the Lock Screen + Dynamic Island while they’re driving
* Gives a persistent “this is running” indicator even if your main app UI is closed
* You can update it locally (no need for push) as long as the app has some runtime (foreground or location-kept in background)

Constraints to keep in mind:
* You don’t want to spam updates every second (battery + ActivityKit limits). - For a driving app, updating every 15–60 seconds is usually enough: - The main important values (elapsed time, time to break) don’t need second-precision.
* Live Activity doesn’t itself keep your app alive forever: - It’s a surface you update while you have background execution (e.g. via location). - It’s perfect as a display + “quick access” to the session, not as the core engine.

So the pattern is:
# User taps Start driving
# You: - Start the session in your own model - Start background location + motion - Start a Live Activity representing that session
# Your engine updates: - Local state (driving time, distance, etc.) - Live Activity state (via ActivityKit)
# When user taps Stop driving: - Finish session in storage - Stop location + motion - End the Live Activity