Tiếng Việt
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日本語Speed alerts that drivers won't want to switch off
A 3 km/h buffer, 30/20/12-second pauses between reminders, and one important exception: if you go further over the limit, the app warns you straight away.
A speed-warning app that the driver switches off cannot warn anyone. Getting this right is a genuine design challenge, not just a finishing touch.
Three ways an alert gets itself switched off
- Flickering on and off. Drive at exactly 60 on a 60 road and the GPS reading wobbles by a few km/h, switching the alert on and off.
- Repeating too often. The same sentence spoken every five seconds along a long stretch of road.
- Interrupting music and not bringing it back. If music is cut off and never comes back, that alone is reason enough for many people to uninstall.
A 3 km/h buffer (hysteresis)
The alert switches on at one threshold and only switches off once you are 3 km/h below it. Small wobbles around the limit therefore cannot cause a stream of on-off alerts — to clear the alert, you need to actually slow down.
Pauses between reminders, by severity
After an alert, the same level stays quiet for 30, 20 or 12 seconds, depending on how far over the limit you are. The further over you are, the more often you are reminded, because the risk is higher too.
The exception that matters most
When the overspeed escalates — from slightly over to well over — the alert sounds immediately, regardless of the pause. That is the moment the driver is speeding up, and when a warning is most valuable. A rigid pause would stay silent at exactly the moment it should speak up.
The +5 km/h safety margin
By default, nothing counts as speeding until you exceed the limit by more than 5 km/h. GPS can be off by a few km/h, and most limits are estimated anyway — with no margin, measurement errors would turn into unnecessary warnings. You can adjust this margin in Settings.
When the device has no Vietnamese voice
Many head units come without a vi-VN text-to-speech engine. An app that relied on speech alone would stay silent on those devices, just when a warning matters most. VoiceAlerts checks whether a voice is available and plays a beep instead if it is not. It also requests transient “ducking” audio focus, so your music is turned down briefly and then restored, rather than cut off.