How to Set a Speed Limit Alert You Will Actually Obey

A speed alert solves a specific problem: reading a number requires looking at it, and looking at it is exactly what you should not be doing. A threshold you set once turns a continuous monitoring task into an occasional notification.

The app does not know the road

This matters enough to state plainly. Speedometer does not hold a database of posted limits and does not read signs. The limit is your number, set in the profile tab, and the alert fires when your GPS speed passes it. Knowing the legal limit for the road you are on remains your job.

That sounds like a weakness, and for a navigation app it would be. For a speed alert it is mostly an advantage: sign databases are frequently out of date, wrong for the lane you are in, and silent about temporary roadworks limits. A number you chose deliberately does not quietly go stale.

Choosing the number

Two facts shape a sensible threshold.

Your dashboard reads high. Regulation permits it, and manufacturers use the allowance; most cars indicate 3 to 7 percent above true speed. So if you drive "at the limit" on the dashboard, your true speed is already a little below it.

GPS measures true speed. A GPS threshold set exactly at the posted limit therefore fires later than your dashboard would suggest — at the point where you are genuinely at the limit.

Practical approach: set the threshold at the posted limit, not below it. You will get a small genuine margin for free, because your dashboard will already be showing a higher number by the time the alert sounds. If you want a real cushion, set it 5 km/h under.

Setting it

1. Open the profile tab.
2. Tap Speed Limit. The default is 0, which disables the alert entirely — this is the single most common reason an alert never fires.
3. Enter your threshold in the unit you have selected. If you are in KMH the number is km/h; switch the unit first if you think in mph.
4. Check that the phone is not silenced if you expect an audible warning.

Using it well

• Set it for the trip, not the moment. Changing the threshold while driving defeats the purpose. Pick it before you pull away.
• One number per road type. City, main road, motorway. Most drivers need three values and use two of them.
• Treat a repeated alert as information. If it fires constantly on a stretch you thought you were driving calmly, that is the app doing exactly its job.
• Do not set it above the limit to silence the nagging. An alert you have configured to never fire is worse than no alert, because it feels like protection.

While the alert is armed, the rest of the app keeps working normally: the live speed on whichever face you prefer, and if you started a session, the distance, average and maximum speed that get filed in your trip history when you stop.