Invalid Laps: How Detection Works, and How to Override It

Not every lap you drive is a fair comparison. A spin, a red flag, or a lap that started mid-corner shouldn't count toward your best lap or your session average — so LapperSnapper checks every lap automatically and flags the ones that don't look like a clean, representative run. You can always see why a lap was flagged, and you can override the decision at any time — including invalidating a lap by hand.

How automatic detection works

Each time you open a session, LapperSnapper compares every lap against the others in that session — lap distance, sector data, and lap time — and sorts anything unusual into one of five categories. Two of them are serious enough that the lap is excluded from your stats automatically; the other three are just flagged with a badge so you can take a closer look, but they still count.

Excluded automatically:

• Incomplete lap — the lap covered noticeably less distance than your other laps, its sector data is broken, or (without GPS) its time is far too short to be real.
• Unusually slow — the lap took noticeably longer than your other laps: a spin, traffic, or a warm-up/cool-down lap.

Flagged, but still counted:

• Unusually short — the lap covers the full distance but is faster than seems plausible next to your other laps. We flag it rather than hide it, since it might be a genuine fast lap.
• Out / in lap — the first or last lap of the session, which is often a partial-pace lap in or out of the pits.
• GPS dropout at a lap boundary — your GPS signal briefly dropped right where this lap starts or ends, so the lap time may be slightly off.

A couple of things worth knowing:

• Nothing is ever deleted. An excluded lap is left out of your best lap, average lap, ultimate lap and coaching — you can still see it, review it, and re-include it.
• Detection needs a full picture. The slow/short/out-in-lap comparisons only run once a session has at least 4 timed laps to compare against. In shorter sessions, only the checks that don't need a comparison apply: broken sector data (incomplete lap) and a GPS dropout at a lap boundary.
• It re-evaluates every time, based on your current set of laps — it isn't a one-time judgment baked in when you drove the lap.

How to invalidate a lap by hand (or restore one)

If LapperSnapper gets it wrong — or you want to invalidate a lap it didn't flag — you can override any lap in your own sessions:

1. Open the session and go to the Laps tab.
2. Long-press the lap you want to change.
3. The lap immediately flips between valid and invalid. You'll see a confirmation (for example "Lap 4 marked invalid") with an Undo option if you change your mind right away.

Look for these indicators on each lap row:

• A greyed-out row with a solid block icon means the lap is currently excluded from your stats.
• An outlined block icon means the lap was flagged as possibly invalid but is still counted — worth a look, but not excluded.

To see why a lap was flagged, press and hold the icon itself on a phone (or hover over it in the web app) — its label names the reason.

Your manual choice is saved on this device and sticks until you change it again. If you flip a lap back to match what automatic detection would have chosen anyway, your override is cleared and the lap goes back to being decided automatically. Overrides aren't restored when you open the same session on another phone or in the web app — there, automatic detection decides again until you override it there too.