Following Distance – Vung Lai

Vững Lái (Vung Lai) is a following-distance and tailgating alert app from DanAI. Mount your phone on the windshield: the rear camera and AI running on the phone itself spot the vehicle ahead in your lane, estimate the distance, and warn you when you follow too closely for your current speed.

THE 2-SECOND AND 3-SECOND RULE, MEASURED FOR YOU
• Canada: the 2-second rule by default, in km/h and metres.
• United States: the 3-second rule by default, in mph and feet.
• Vietnam: Circular 38/2024/TT-BGTVT for dry roads (35 m at 60 km/h; 55 m up to 80 km/h; 70 m up to 100 km/h; 100 m up to 120 km/h), with a 1-second reminder from 20 km/h below those speeds.
• The region is guessed from your phone and can be changed in Settings. You can also pick any time-gap rule or set your own distance table.
• Speed comes from the phone's GPS.

ALERTS YOU DON'T HAVE TO LOOK AT
• Under the safe following distance: shown in amber, and spoken once it lasts a few seconds. Really close (under 3/4 of the safe distance, held for a full second): red, sounded at once.
• Tones, vibration and voice prompts in English or Vietnamese (follows the app language).
• Voice styles: standard, friendly, cheerful, or your own custom lines.
• Forward collision warning when the gap closes quickly.
• Lane departure warning.
• Speed-limit sign reminder (in Vietnam).
• Three sensitivity levels: Calm (warns later and less), Balanced, Sensitive (earlier and more).

DRIVER ASSISTANCE (ADAS) ON THE PHONE YOU ALREADY HAVE
• No extra hardware: a windshield phone mount is all you need.
• Mount assistant to place the phone at the right spot and angle; a level and a faint hood outline help put it back where it was.
• Automatic camera calibration while you drive.
• Floating window (picture-in-picture) to use alongside your navigation app.
• Day and night themes, plus a HUD mirror mode.
• Trip history; GPS route saving if you turn it on (off by default).
• The phone's temperature shows in a corner of the screen; when it gets hot, the app scales back its processing to keep running smoothly.

PRIVACY
• Camera images and location are processed on the phone and never uploaded.
• The app goes online only to download the signed distance table (with none of your data) and for tips through Google Play.
• No account, no sign-in, no ads, no tracking.
• Settings and trip history stay on your phone; clearing the app's data removes everything.
• Location is used only while the app is open.

FREE
Every feature is free. If you like, you can support the developer through Google Play; tips are voluntary and unlock nothing extra.

SAFETY NOTICE
Vững Lái is an assistance tool only. It is not a certified measuring device, it does not control your vehicle, and its estimates can be wrong, especially at night, in rain or fog, against the sun, or with a dirty windshield. The driver is always responsible for watching the road, keeping a safe distance and obeying traffic law. Set the app up before you drive, mount the phone where it does not block your view, and do not operate the phone while moving. Intended for licensed drivers.

Requires Android 8.0 or later with a rear camera and GPS. Performance depends on your phone.

Support: [email protected]